RD 34.20.591-97 "Guidelines for the conservation of thermal power equipment

Russian Joint Stock Company for Energy and Electrification "UES of Russia"

Department of Science and Technology

METHODOLOGICAL INSTRUCTIONS FOR THE PRESERVATION OF HEAT AND POWER EQUIPMENT

RD 34.20.591-97

Expiry date set

from 01.07.97 until 01.07.2002

UDC 621.311.22:621.1.002.5

Developed firm for adjustment, improvement of technology and operation of power plants and networks "ORGRES" and JSC VTI

Performers IN AND. Startsev (JSC Firma ORGRES), E.Yu. Kostrikina, T.D. Modestov (JSC VTI)

Approved Department of Science and Technology of RAO "UES of Russia" 14.02.97

Head A.P. BERSENEV

These Guidelines apply to power and hot water boilers, as well as turbine plants of thermal power plants.

The guidelines define the main technological parameters of various conservation methods, establish criteria for choosing methods or a combination (combination) of methods, the technology for their implementation on boilers and turbine plants when put into reserve or repair, taking into account a sharp increase in both the number of shutdowns and the duration of equipment downtime at power plants.

With the introduction of these Guidelines, the "Guidelines for the conservation of thermal power equipment: RD 34.20-591-87" (M .: Rotaprint VTI, 1990) become invalid.

1. GENERAL PROVISIONS

1.1. Preservation of boilers and turbine plants is carried out to prevent corrosion of the metal of internal surfaces both during operational shutdowns (putting into reserve for a certain and indefinite period, putting into current, medium and major repairs, emergency shutdown), and during shutdowns into a long-term reserve or repair (reconstruction) for more than 6 months.

1.2. On the basis of the Guidelines, each power plant should develop and approve a technical solution for the organization of conservation of specific equipment, which determines the methods of conservation for various types of shutdowns and downtime, the process flow diagram and auxiliary conservation equipment. When developing a technical solution, it is advisable to involve a specialized organization.

1.3. Preservation methods not provided for by the Guidelines are allowed to be used with the permission of the Department of Science and Technology of RAO "UES of Russia".

1.4. When developing a technological scheme for conservation, it is advisable to use as much as possible standard installations for corrective treatment of feed and boiler water, installations for chemical cleaning of equipment, and tank facilities of a power plant.

The technological scheme of conservation should be as stationary as possible, reliably disconnected from the working sections of the thermal scheme.

It is necessary to provide for the neutralization or neutralization of waste water, as well as the possibility of reusing preservative solutions.

1.5. In accordance with the adopted technical decision, an instruction for equipment conservation is drawn up and approved with instructions on preparatory operations, conservation and de-preservation technology, as well as safety measures during conservation.

1.6. When preparing and carrying out work on conservation and re-preservation, it is necessary to comply with the requirements of the Safety Regulations for the operation of thermal mechanical equipment of power plants and heating networks. Also, if necessary, additional safety measures related to the properties of the chemicals used should be taken.

1.7. Neutralization of spent preservative solutions of chemical reagents should be carried out in accordance with the instructions "Typical operating instructions for installations for the treatment of industrial wastewater from thermal power plants: TI 34-70-043-85 (M.: SPO Soyuztekhenergo, 1985).

2. METHODS FOR PRESERVATION OF DRUM BOILERS

2.1. Dry shutdown of the boiler

2.1.1. Draining the boiler at a pressure above atmospheric pressure allows, after emptying, due to the heat accumulated by the metal, lining and insulation, to keep the temperature of the metal in the boiler above the saturation temperature at atmospheric pressure. In this case, the internal surfaces of the drum, collectors and pipes are dried.

2.1.2. Dry shutdown (CO) is used for boilers for any pressure in the absence of rolling joints of pipes with a drum in them.

2.1.3. Dry shutdown of the boiler is carried out during a planned shutdown for reserve or repair for a period of up to 30 days, as well as during an emergency shutdown.

2.1.4. To prevent moisture from entering the boiler during downtime, it is necessary to provide for its reliable disconnection from water and steam pipelines under pressure by tightly closing the shut-off valves, installing plugs, revision valves.

2.1.5. After the boiler is stopped in the process of its natural cooling or cooling down, drainage is started at a pressure of 0.8-1.0 MPa.

The intermediate superheater is devaporated onto the condenser. After draining and drying, all valves and valves of the steam-water circuit of the boiler, manholes and dampers of the furnace and flue are closed, revision valves are opened, and plugs are installed if necessary.

2.1.6. During the conservation period after complete cooling, periodic monitoring of the ingress of water or steam into the boiler is carried out by probing the areas of their possible ingress in the area of shut-off valves, short-term opening of drains of the lower points of collectors and pipelines, valves of sampling points.

If water ingress into the boiler is detected, measures should be taken to eliminate this ingress. After that, the boiler is melted, the pressure in it is raised to 1.5-2.0 MPa, this pressure is maintained for several hours, and then CO is produced again.

If it is impossible to eliminate the causes of moisture ingress or to kindle the boiler, conservation is carried out by maintaining excess pressure in the boiler (see clause 2.2).

2.1.7. If, during the downtime of the boiler, repair work was carried out on the heating surfaces and it became necessary to pressure test, then after pressure testing, conservation is continued by maintaining excess pressure in the boiler (see clause 2.2).

2.1.8. When the boiler is removed from the CO, the installed plugs are removed and the firing operations are started in accordance with the instructions for starting the boiler.

2.2.1. Maintaining a pressure above atmospheric pressure in the boiler prevents the access of atmospheric oxygen to it.

2.2.2. Overpressure (IP) is maintained when deaerated water flows through the boiler.

2.2.3. Preservation while maintaining ID is used for boilers of any type and for any pressure.

2.2.4. The ID method is carried out when the boiler is put into reserve or repair, not related to work on the heating surfaces, for a period of up to 10 days.

On boilers with rolling joints of pipes with a drum, the ID method can be used for up to 30 days.

2.2.5. Feed or make-up water can be used to maintain the ID in the boiler.

The use of make-up water is possible provided that the pH value of this water is not lower than 9.0, and the oxygen content in it is not more than the oxygen content in the feed water of the mothballed boiler.

2.2.6. At block power plants, to supply feed or make-up water to the boiler for the period of conservation, it is necessary to install a collector and pipelines to it from each deaerator at a pressure of 0.6 MPa or a collector from the pressure side of the make-up water transfer pumps, as well as pipelines from the collector to the pressure pipeline of feed pumps each block.

2.2.7. At power plants with cross connections, the feed water supply to the boiler can be carried out through an existing or specially installed bypass of the feed unit with a diameter of 20-50 mm (with a throttling washer).

To use make-up water from transfer pumps, jumpers are installed from the boiler filling pipeline to the feed pipelines in front of the economizer (E).

At power plants where there is a special conservation pump (Fig. 1), this pump can be used to supply feed water to the boiler. When implementing this scheme, water is supplied to the inlet to the water economizer and to the outlet collectors of the superheater.

2.2.8. The discharge of conservation water from the boiler is carried out through the drains of the outlet sections of the superheater into drainage tanks or when implementing the scheme shown in fig. 1, through the lower points of the boiler into the deaerator or lower tanks.

Rice. 1. Scheme of conservation of drum boilers for maintenance, protection, PV:

1 - tank for the preparation of chemical reagents with a capacity of 2-10 m 3; 2 - preservation pump with a supply of 30-100 m 3 /h and a pressure of 0.5-0.8 MPa; 3 - reagents; 4 - make-up water;

5 - into the deaerator (drainage tank, make-up water tank); 6 - from other boilers;

7 - into the bubbler; 8 - feed water to the boiler; 9 - screens; 10 - feed water deaerator; 11 - on the suction side of the PEN; 12 - to other boilers;

Conservation pipelines

The water discharged from the boiler must be used in the steam-water cycle of the power plant, for which it is necessary to provide for the pumping of this water to neighboring blocks at block power plants.

2.2.9. On pipelines for supplying and discharging conservation water to disconnect them from the boiler during its operation, it is necessary to provide for the installation of shut-off valves, inspection valves or plugs.

2.2.10. After stopping the boiler and reducing the pressure to atmospheric, water is drained from it, after which the boiler is filled with conservation water and its flow through the boiler is organized.

The filling of the boiler is controlled by air vents, and the pressure and water flow are regulated using valves on the inlet and outlet pipelines. At block power plants, if possible, they include HPH in the duct scheme.

2.2.11. During the conservation period, the boiler maintains a pressure of 0.5-1.5 MPa and a water flow at a rate of 10-30 m 3 /h. Every shift, water samples are taken from the clean and salt compartments of the superheater to determine the oxygen content.

When the pressure value goes beyond the specified limits, it is regulated by inlet and outlet valves.

During conservation according to the scheme of Fig. 1 conservation pump can be used to maintain the ID on several boilers at the same time.

2.2.12. Upon completion of conservation, the boiler is drained to the kindling level and start kindling in accordance with the instructions for starting the boiler.

2.3.1. Under the influence of an aqueous solution containing hydrazine, a protective oxide film is formed on the metal surface at high temperatures. A relatively small part of the iron oxides located on the metal surface participate in the formation of the film. Part of the available iron and copper oxides, due to reduction to ferrous and metallic forms, as well as the formation of complex compounds, loses its strong bond with the metal and is removed from the heating surfaces.

During the HE process of the economizer and screens, the heating surfaces of the superheater are filled with steam containing ammonia, which ensures passivation of these surfaces as well and protects the superheater during steam condensation after the boiler cools down.

The concentration of hydrazine during processing significantly exceeds the operating norm and depends on the temperature of the medium and the duration of processing. The greatest efficiency is achieved at the highest possible ambient temperatures.

2.3.2. When treating the boiler with hydrazine at operating parameters (HF), depending on the expected downtime, the content of hydrazine in the feed water is 0.3-3.0 mg/kg, and the duration of treatment is from 1-2 to 24 hours.

2.3.3. The hydraulic fracturing method is used on those boilers where corrective treatment of feed water with hydrazine is carried out.

2.3.4. Hydrazine treatment at operating parameters is carried out before a planned shutdown of the boiler for reserve or repair for up to 30 days.

This treatment followed by a dry shutdown (fracturing + CO) can be carried out before a planned shutdown of the boiler in reserve for a period of up to 60 days, as well as before a shutdown for medium or major repairs.

2.3.5. At block power plants, it is advisable to do the hydrazine dosing using a standard hydrazine unit on the suction side of the feed pumps.

2.3.6. In cross-linked power plants, hydrazine is dosed into the feed water before E.

For dosing hydrazine with an individual-group scheme of phosphating, standard phosphate dosing pumps should be used. Schematic diagram of hydrazine dosing (Fig. 2): hydrazine hopper tank with a capacity of 1-2 m 3 - hydrazine solution collector on the suction side of phosphate pumps - phosphate dosing pump - phosphate line - jumper from the phosphate line to the boiler feed unit.

With an individual phosphating scheme and the location of phosphate units at a considerable distance from each other, it is advisable to mount a separate unit for all or a group of boilers, including a hydrazine hopper tank and two dosing pumps (phosphate type) for supplying hydrazine to the feed unit of each boiler.

The hydrazine piping may cut into any feeder bypass or drain piping.

2.3.7. A supply of a strong hydrazine solution from the hydrazine facility and make-up water should be provided for the measuring tank.

In this tank, immediately before treatment, a solution of the required concentration is prepared, taking into account the performance of the dosing pump, the required content of hydrazine in the feed water and the expected load of the boiler.

Rice. 2. Scheme of preservation of drum boilers for hydraulic fracturing, GRO, GV, TO, ZShch, FV:

1 - tank for the preparation of chemical reagents with a capacity equal to the water volume of the boiler with a superheater; 2 - pump for filling the boiler with a solution of chemical reagents with a supply of 50-100 m 3 / h, a pressure of 0.5-0.8 MPa; 3 - hydrazine measuring tank with a capacity of 1-2 m 3;

4 - standard phosphate dosing pumps; 5 - tank of working solution of phosphate;

6 - hydrazine; 7 - ammonia; 8 - make-up water; 9 - to boiler No. 2; 10 - to phosphate pumps of other boilers; 11 - to the neutralization unit; 12 - to the drainage collectors of other boilers; 13 - make-up water; 14 - chemical reagents; 15 - feed water to the boiler;

16 - screens; 17 - into the bubbler;

Conservation pipeline;

G - hydrazine pipeline for conservation;

F - regular line of phosphating

2.3.8. Hydrazine treatment is carried out immediately before the planned shutdown of the boiler. 1-2 hours before the start of treatment, the dosing of phosphates into the boiler is stopped. Depending on the downtime of the boiler, the approximate duration of treatment and the content of hydrazine in the feed water before the boiler are:

At the end of the predetermined treatment time, the boiler is stopped. When shutting down to standby for up to 10 days, the boiler may not be drained. In case of a longer downtime, a SA should be performed after the hydraulic fracturing.

2.3.9. In case of emergency pressure testing of the boiler during downtime, it is allowed to fill the boiler with water for a period of not more than 1 day, followed by drainage of water.

2.4.1. Treatment of heating surfaces with hydrazine with ammonia in boiler shutdown mode

2.4.1.1. The formation of a protective film on the metal surface is carried out under the influence of an aqueous solution of hydrazine. Under conditions of lower temperatures compared to hydraulic fracturing, for a stronger bonding of the protective oxide film with the metal, the pH value of the preservative solution increases due to ammonia.

2.4.1.2. Processing is carried out on a boiler disconnected from the turbine at a pressure of not more than 10 MPa. The pH value of the preservative solution is 10.5-11, and the content of hydrazine in the clean compartment of the drum is 10-60 mg/kg, depending on the idle time. The duration of treatment should be at least 3 hours.

2.4.1.3. Shutdown Ammonia Hydrazine Treatment (SHT) is used on boilers using hydrazine for feedwater correction treatment.

2.4.1.4. GRW treatment is carried out when the boiler is put into reserve for a period of up to 60 days or when it is put into medium or major repairs. It is advisable to carry out this treatment also when the boiler is taken into reserve or repaired for up to 30 days, if the boiler had a long non-stop campaign (more than 3-4 months) in the previous period or serious violations of the feed water quality standards for iron.

Hydrazine treatment in the shutdown mode can be carried out both directly during the shutdown process, and after a special kindling of a previously stopped boiler.

2.4.1.5. At block power plants, dosing of hydrazine and ammonia is carried out jointly by standard phosphate dosing pumps into the drum. The working solution of reagents is prepared either in a phosphate measuring tank, or in a specially installed measuring tank, where it is necessary to bring hydrazine and ammonia pipelines from the respective farms and make-up water.

2.4.1.6. In cross-linked power plants, hydrazine and ammonia are metered together into a drum. The dosing scheme is organized in accordance with paragraphs. 2.3.6 and 2.3.7.

2.4.1.7. The working solution of reagents is prepared in a measuring tank at the rate of one treatment with a certain margin. To provide the required concentrations of reagents in the boiler as quickly as possible, taking into account the water volume of the boiler and the productivity of dosing pumps, the concentration of hydrazine in the working solution should be 5-20%, and ammonia 1-5%.

2.4.1.8. The need for 20% hydrazine for one treatment depends on the contamination of the heating surfaces of the boiler, the frequency of treatment and usually does not exceed 1 liter of hydrazine per 1 m 3 of water volume of the boiler (without superheater). The need for 25% ammonia does not exceed 0.5 l per 1 m 3 of the water volume of the boiler.

2.4.1.9. To discharge the used preservative solution after treatment, a pipeline must be provided from the lower drainage collector of the boiler to the reagent tank (see Fig. 2) or some kind of drainage tank, a tank for draining from the boiler, a tank of low points, a pit for subsequent pumping to the neutralization unit .

2.4.1.10. To carry out processing on a block with a drum boiler, the block is unloaded to the minimum allowable load and, in parallel, the temperature of the superheated steam is reduced. The boiler is switched to ignition fuel consumption. When the fuel consumption is not higher than 30% of the nominal one, the BROU (PSBU) opens and the turbine is turned off, and the intermediate superheater is deevaporated to the condenser.

By reducing the fuel consumption, the temperature of the live steam is lowered to 350-400°C, after which the steam is gradually released into the atmosphere from the main steam pipelines or from the pipeline downstream of the ROU and the BROU (PSBU) is closed, maintaining a pressure of about 10 MPa in the boiler.

The boiler is fed with water to a level of +100 mm above the upper allowable level, the continuous purge is closed, and the dosing of reagents into the drum is started. The boiler water recirculation line is switched on from the drum to the E inlet. The recirculation line is turned off only for the period of feeding the boiler with water.

Processing starts when the clean compartment reaches a pH value of ³ 10.5 and a hydrazine content depending on the downtime:

Simple, days	Hydrazine content, mg/kg
Up to 15	10-30
Up to 45	30-50
Up to 60	40-60

If the concentration of hydrazine in the first hour of treatment decreases by 25-30% compared to the initial one, then it is necessary to introduce an additional amount of reagents into the boiler.

Processing ends with a decrease in the content of hydrazine in the water of the salt compartment by 1.5-3 times compared with the original. The total duration of treatment should be at least 3 hours.

In the process of processing control pH, the content of hydrazine in clean and salt compartments.

2.4.1.11. At power plants with cross-links, the boiler is unloaded to the minimum load for processing, the shut-off valves are opened on the steam discharge line to the atmosphere and the valves on the steam pipelines to the general station main are closed. The boiler is switched to starting fuel, the flow rate of which must provide a superheated steam temperature of 350-400 ° C at an operating pressure behind the boiler (but not higher than 10 MPa). The boiler is fed with water to a level of +100 mm above the upper allowable level, the continuous purge is closed, and the dosing of reagents into the drum is started. The boiler water recirculation line is switched on from the drum to the E inlet. The recirculation line is turned off only for the period of feeding the boiler with water.

The pH value, the content of hydrazine in the clean and salt compartments, the duration of treatment, the amount of chemical control, as well as the operations after the end of the treatment must comply with clause 2.4.1.10.

2.4.1.12. To carry out treatment on a previously stopped boiler, it is necessary to melt it in accordance with the operating instructions, raise the parameters and perform treatment, and then put the boiler into reserve or repair in accordance with paragraphs. 2.4.1.10 or 2.4.1.11.

2.4.1.13. In case of emergency pressure testing of the boiler during the idle period, it is allowed to fill the boiler with water for a period of not more than 1 day, followed by drainage of water.

2.4.1.14. Before kindling the boiler, special water washes of heating surfaces are not carried out.

2.4.2. Hydrazine "cooking" of boiler heating surfaces

2.4.2.1. During hydrazine "boiling" (HW), a protective film is formed on the metal surface under conditions of a lower ambient temperature compared to GRW.

2.4.2.2. Hydrazine "cooking" is carried out at a pressure in the boiler of about 1.5 MPa and maintaining the content of 150-200 mg/kg of hydrazine in the clean compartment of the drum and a pH value of more than 10.5 (due to the dosing of ammonia). The duration of the mode is 20-24 hours.

2.4.2.3. Hydrazine "cooking" is used on boilers using hydrazine for corrective treatment of feed water, instead of GDS, if the noise from the discharge of steam into the atmosphere during the GDS disturbs the surrounding population.

2.4.2.4. Hydrazine "cooking" is carried out in the cases specified in clause 2.4.1.4, and can also be carried out both directly during the shutdown process and during special kindling of the mothballed boiler.

2.4.2.5. The scheme for the preparation and dosing of hydrazine and ammonia is carried out in accordance with paragraphs. 2.4.1.5-2.4.1.7, and the discharge of the solution after treatment - item 2.4.1.9.

2.4.2.6. The need for 20% hydrazine usually does not exceed 1.5 l of hydrazine, and 25% ammonia 0.5 l per 1 m 3 of water volume of the boiler (without a superheater).

2.4.2.7. At block power plants, after stopping the unit, the pressure in the boiler is reduced at an acceptable rate by dumping steam through the BROU (PSBU) into the condenser. The superheater is devaporated on the condenser.

After reducing the pressure in the boiler to 1.5 MPa, 2-3 nozzles are turned on, the valve is opened on the steam discharge line to the atmosphere and the BROU (PSBU) is closed. The pressure in the boiler is maintained within 1.5-2.0 MPa, for this it is allowed to periodically open the shut-off valves on the steam discharge line to the atmosphere.

The concentration of hydrazine in the clean compartment of the drum should be at least 150-200 mg/kg, pH value > 10.5. The duration of the regime is 20-24 hours.

During processing, the pH value and the content of hydrazine in the clean compartment are controlled.

At the end of the treatment, the boiler is stopped and, when it is taken out for repair, after the pressure is reduced to atmospheric pressure, it is emptied, directing the solution to neutralization.

When the boiler is taken into reserve, the preservative solution can be drained before starting the boiler firing.

2.4.2.8. At power plants with cross connections, after stopping the boiler and disconnecting it from the general station line, shutoff valves are opened on the steam discharge line to the atmosphere.

After reducing the pressure in the boiler to 1.5 MPa, 2-3 nozzles are turned on, maintaining a pressure of 1.5-2.0 MPa, periodically opening the valve on the steam discharge line to the atmosphere.

The boiler is fed with water to a level of +100 mm above the upper allowable level, the continuous purge is closed, and the dosing of reagents into the drum is started. The boiler water recirculation line is switched on at the input E, turning it off only for the period of feeding the boiler with water.

The pH value, the content of hydrazine in the clean compartment, the duration of treatment, the amount of chemical control, as well as the operations after the end of the treatment must comply with clause 2.4.2.7.

2.4.2.9. To carry out treatment on a previously stopped boiler, it must be melted in accordance with the operating instructions, raise the parameters and perform treatment in accordance with paragraphs. 2.4.2.7 or 2.4.2.8, and then take the boiler into reserve or repair.

2.4.2.10. In case of emergency pressure testing of the boiler during the idle period, it is allowed to fill the boiler with water for a period of not more than 1 day, followed by drainage of water.

2.4.2.11. Before kindling the boiler, special water washes of heating surfaces are not carried out.

2.5.1. Passivation of heating surfaces with Trilon B solution is based on the thermal decomposition of preformed iron complexonates.

At the first stage of processing at an ambient temperature of about 150°C, the heating surfaces of the E and screens are prepared for the creation of a protective film on them due to the complexing of iron from deposits and its transfer into solution. At the second stage, at an ambient temperature of more than 250°C, thermolysis of a part of the iron complexonates occurs with the formation of a protective film on the metal surface.

During the decomposition of iron complexonates, gaseous products are released, including hydrogen and ammonia, which are removed with steam and passivate the superheater.

The technology of trilon treatment (TO) is regulated by RD 34.37.514-91 "Guidelines for the complex treatment of water in drum boilers with a pressure of 3.9-9.8 MPa" (M.: SPO ORGRES, 1993).

2.5.2. Passivation of heating surfaces with triton B is combined with the kindling of the boiler.

The estimated concentration of Trilon B in the water filling the boiler before kindling should be 300-500 mg/kg.

At the first stage of processing, the pressure of 0.5-1.0 MPa is maintained in the boiler for 1.5-2 hours, and the second stage is carried out in the process of further kindling according to the operating instructions.

2.5.3. Treatment with Trilon B is used for all types of drum boilers with a pressure above 3.9 MPa, regardless of the modes of corrective treatment of feed water (hydrazine-ammonia or ammonia) and boiler water (phosphate or complexone).

2.5.4. On boilers where corrective treatment of feed water with hydrazine is provided, maintenance is carried out after chemical treatment (pre-commissioning and operational), before overhaul and after it, trilon treatment can also be carried out before putting the boiler into reserve or repair for up to 60 days. In these cases, TO replaces GRO, GV, HF.

At power plants where the use of hydrazine is prohibited by sanitary standards for the supply of steam to consumers, maintenance is carried out, in addition to the indicated cases, at least once a year, for example, after the autumn-winter maximum.

For maintenance before putting it into reserve or repair, it is necessary to provide for a special kindling of the boiler with access to operating parameters no earlier than one or two weeks before the shutdown.

If maintenance is carried out immediately before the boiler is taken into reserve or repair, it is advisable to perform CO during shutdown.

2.5.5. To carry out maintenance, it is necessary to provide a tank for preparing the working solution of Trilon B, a pump for supplying the solution to the boilers and pipelines for filling the boilers through the lower points of the screens and drains E (see Fig. 2). It is necessary to bring the make-up water pipeline to the tank. The capacity of the tank must not be less than the water volume of the largest boiler.

To prepare the working solution of Trilon B, acid washing tanks and pumps and pipelines for filling boilers with water can be used.

2.5.6. Estimated need for Trilon B for one treatment of the boiler is 0.5-1.0 kg of marketable product per 1 m 3 of water volume (without superheater) of the boiler.

2.5.7. A solution of Trilon B with a concentration of 300-500 mg/kg is prepared in an amount sufficient to fill the boiler to the kindling level. If the capacity of the tank is insufficient for this, then the concentration of the solution is increased, taking into account that, after feeding the boiler to the kindling level, the concentration of Trilon B in the boiler water is within the specified limits.

The commercial product is poured into the tank in portions through a mesh basket, washing off the reagent with water from a hose, with water recirculation according to the "tank - pump - tank" scheme.

2.5.8. After filling through the lower points of the screens and drains, they start firing up the boiler.

For the entire period of kindling, the continuous blowdown of the boiler must be closed. The boiler water recirculation line to the E inlet is closed only for the period of feeding the boiler with water.

Upon reaching a pressure of 0.5-1.0 MPa in the boiler, an exposure is made for 1.5-2.0 hours. During the exposure, water samples of clean and salt compartments are taken every 20-30 minutes to determine the concentrations of free trilon. If the water samples are turbid and contain a suspension or the content of free trilon is less than 30 mg/kg, the kindling is stopped, the solution is drained from the boiler. Then the boiler is refilled with a fresh solution of Trilon B with a concentration of more than 30 mg/kg and start kindling.

After the end of exposure at a pressure of 0.5-1.0 MPa or after filling the boiler with fresh solution, kindling is carried out according to the operating instructions for connecting the boiler to the turbine.

2.6.1. Phosphate-ammonia "boiling" (PH) with increased phosphate content in boiler water compared to operating pressure and pressure in the boiler of 0.8-1.0 MPa contributes to phosphate passivation of the metal of the inner heating surfaces of the screens and the removal of part of the loose deposits.

In this case, the superheater is filled with steam containing ammonia, which contributes to the passivation of the metal of the superheater and protects it during steam condensation after the boiler is stopped.

2.6.2. Phosphate-ammonia "cooking" is carried out in the boiler firing mode at a pressure of about 1.0 MPa, the initial concentration of phosphates in the boiler water is 400-500 mg/kg and ammonia is about 1 g/kg. Processing time is about 8 hours.

2.6.3. Phosphate-ammonia "cooking" is used on boilers with a pressure of 3.9 and 9.8 MPa, fed with softened water.

2.6.4. Phosphate-ammonia "cooking" is carried out when the boiler is put into reserve for a period of up to 60 days or when it is put into medium or major repairs.

2.6.5. For the preparation of solutions, their supply to the boiler, as well as the collection of waste solutions with subsequent pumping to the neutralization unit, it is necessary to provide a scheme in accordance with Fig. 1 or 2.

2.6.6. Estimated need for one treatment - 1-1.5 kg of commercial trisodium phosphate and 3-3.5 liters of 25% ammonia per 1 m 3 of water volume of the boiler.

2.6.7. A solution of reagents with a concentration of phosphates of about 500 mg/kg and ammonia with a concentration of about 1 g/kg is prepared in a tank (see Fig. 1 and 2) in an amount sufficient to fill the boiler to the kindling level. If the capacity of the tank is insufficient for this, then the concentration of the solution is increased, taking into account that after feeding the boiler to the ignition level, the concentration of phosphate and ammonia in the boiler water reaches the indicated ones.

Backfilling of trisodium phosphate is carried out in accordance with clause 2.5.7.

2.6.8. After filling through the lower points, they begin to kindle the boiler. For the entire period of processing, continuous blowing is closed, the boiler is maintained at a pressure of 1.0 MPa, EF is maintained for 8 hours. Every 1-2 hours, the lower points of the screens are blown, starting from the panels of the salt compartments. The duration of the opening of the intermittent blowdown valves is 30 s.

At the end of the PV, the boiler is stopped and, after the pressure is reduced to atmospheric pressure, it is emptied, directing the solution to neutralization.

2.6.9. Before putting the boiler into operation, special water washing of heating surfaces is not carried out.

2.7.1. When the heating surfaces of the boiler are filled with a protective alkaline (PS) solution, the stability of the protective film previously formed on the metal surfaces is ensured for a long time even if oxygen enters the boiler.

As alkaline solutions, ammonia solution or sodium hydroxide solution with trisodium phosphate can be used.

2.7.2. When implementing this method, the boiler is completely (except for the intermediate superheater) filled with an alkaline solution for the entire shutdown period.

When using an ammonia solution, its pH value should be 10.5-11 (ammonia content 0.5-1.0 g / kg), and the phosphate-alkaline solution should contain 0.3-1 g / kg sodium hydroxide and 0.1 -0.2 g/kg trisodium phosphate.

During the conservation period, it must be possible to pump the solution in case of leakage of part of it from the boiler.

2.7.3. Filling with ammonia solution is used for boilers of any pressure.

A solution of caustic soda with trisodium phosphate is used for boilers fed with softened water, and also provided that all heating surfaces of the superheater can be completely drained.

2.7.4. Filling with an alkaline solution is carried out when the boiler is put into reserve for up to 4 months.

If, before filling with an alkaline solution, the HE (GRW or HW) or HT (GRW+ZShch; TS+ZShch) is treated, then the boiler can be put into reserve for up to 6 months.

2.7.5. In the case of using a sodium hydroxide solution with trisodium phosphate, it is necessary to provide for the possibility of washing the superheater from the preservative solution (see Fig. 1). The use of such a scheme allows, in addition, to organize the recirculation of the solution in the boiler, which is necessary with a relatively small capacity of the tank for preparing the solution.

When using the scheme shown in fig. 2, it should be noted that the capacity of the tank must not be less than the water volume of the largest boiler (with a superheater).

Conservation schemes should also provide for the collection of waste solutions with their subsequent pumping to the neutralization plant.

2.7.6. The approximate need for reagents to fill the boiler per 1 m 3 of water volume is: no more than 4 liters of 25% ammonia when preparing an ammonia solution, and when using sodium hydroxide with trisodium phosphate, no more than 2 liters of 40% alkali and 1 kg of commercial trisodium phosphate.

2.7.7. When using the scheme shown in fig. 2, prepare a solution of the required concentration in a volume sufficient to fill the boiler.

When using the scheme shown in fig. 1, the concentration of reagents is increased in such a way that after feeding the boiler with water and mixing the solution by recirculation ("tank - boiler - tank"), the concentration reaches the required one.

The preparation of solutions is carried in accordance with clause 2.5.7.

2.7.8. The boiler put into reserve and emptied is filled with a preservative solution through the lower points of the screens and drains E. The filling of the boiler is controlled using air vents.

If the mixing of the solution in the boiler is carried out by recirculation (see Fig. 1), then its completion is determined by equalizing the concentration of the solution at the sampling points along the steam-water path.

After filling the boiler, close all the shut-off valves of the steam-water path.

2.7.9. During the period of conservation of the boiler, the tightness of the closure of valves and valves is regularly checked, leaks and leaks in the glands are promptly eliminated.

With partial emptying, the boiler is fed with a fresh solution of reagents.

2.7.10. At the end of conservation, the solution from the boiler is drained into the reagent tank, using, if necessary, to fill another preserved boiler or directing it to the neutralization unit.

If the boiler was preserved with a solution of caustic soda with trisodium phosphate, before kindling, the superheater is washed with water for 30-60 minutes with the discharge of water through the lower points of the boiler. The superheater flushing line must be reliably disconnected from the operating boiler.

2.8.1. Filling the internal heating surfaces with chemically inert nitrogen, followed by maintaining its excess pressure in the boiler, prevents the access of oxygen, which ensures the stability of the previously formed protective film on the metal for a long time.

2.8.2. Filling the boiler with nitrogen is carried out at excess pressure in the heating surfaces. During the conservation process, the nitrogen flow must provide a slight overpressure in the boiler.

2.8.3. Preservation with nitrogen is used on boilers of any pressure at power plants that have nitrogen from their own oxygen plants. In this case, the use of nitrogen at its concentration not lower than 99% is allowed.

2.8.4. Filling with nitrogen is carried out when the boiler is taken into reserve for a period of up to one year.

2.8.5. The conservation scheme should provide for the supply of nitrogen to the outlet manifolds of the superheaters and to the drum through the air vents.

The supply to the air vents is carried out by means of tie-in pipes with high-pressure fittings. The outlets from the air vents should be combined into a common manifold, which is connected to the nitrogen supply pipeline. The collector connecting the outlets from the air vents must be reliably disconnected from the nitrogen pipeline by installing high pressure fittings. On this collector it is necessary to have an inspection valve open during the operation of the boiler.

A specific nitrogen piping scheme is developed taking into account the capabilities of the oxygen plant and the types of boilers installed.

2.8.6. When the boiler is stopped for up to 10 days, conservation is carried out without draining water from the heating surfaces.

After the boiler is stopped and the pressure in the drum is reduced to 0.2-0.5 MPa, the valves are opened on the nitrogen supply lines to the superheater and to the drum and, if necessary, the boiler is drained, after which the drains are closed.

During conservation, the gas pressure in the boiler is maintained at 5-10 kPa.

2.8.7. During the conservation period, measures are taken to identify possible gas leaks and eliminate them.

2.8.8. If it is necessary to carry out minor repairs, a short-term interruption of the gas supply to the boiler is possible.

2.9.1. Contact inhibitor M-1 is a salt of cyclohexylamine and synthetic fatty acids.

In the form of an aqueous solution, a contact inhibitor (CI) protects cast iron and steel of various grades from corrosion. Its protective properties are due to the presence of amino groups in the hydrophobic part of the molecule in the inhibitor. Upon contact with the metal surface, the inhibitor is adsorbed on the amino group, leaving the hydrophobic part of the molecule in the environment. This structure of the adsorption layer prevents the penetration of moisture or electrolyte to the metal. An additional obstacle is the overlying layers of inhibitor molecules, which enhance the adsorption layer. Molecules of water and gases (SO 2 , CO 2 et al.) penetrating deep into this layer lead to the hydrolysis of part of the inhibitor molecule. This releases cyclohexylamines and fatty acids. Cyclohexylamines bind acid gases, and acids, being adsorbed, maintain the hydrophobicity of the metal surface.

The contact inhibitor creates a protective film on the metal, which remains even after draining the preservative solution.

2.9.2. To preserve the heating surfaces, the boiler is filled with an aqueous solution of an inhibitor with a concentration of 0.5-1.5%, depending on the downtime, composition and amount of deposits on the heating surfaces. The specific concentration of the inhibitor solution is established after a chemical analysis of the sediment composition.

2.9.3. CI conservation is used for any types of boilers, regardless of the applied modes of corrective treatment of feed and boiler water.

2.9.4. Conservation with M-1 inhibitor is carried out when the boiler is taken into reserve or repaired for a period of 1 month. up to 2 years.

2.9.5. For the implementation of conservation, a special separate scheme for preparing an aqueous solution of the inhibitor and feeding it into the boiler should be provided (Fig. 3). The scheme includes a tank for storing and preparing a solution with a capacity of at least the full water volume of the boiler and a pump for mixing the solution and supplying it to the boiler. The tank must be provided with a supply of condensate or demineralized water.

Filling the boiler with the inhibitor solution is carried out through the pipeline from the pressure side of the pump to the lower drainage collector of the boiler. Through the same pipeline, the preservative solution from the boiler is discharged into the storage tank during depreservation.

2.9.6. To prepare a working solution, flasks with a commercial inhibitor are preheated by immersing them in a bath of water heated to 70°C. Approximate warm-up time - 8-10 hours.

The heated commercial inhibitor is poured into the preservative solution tank with water recirculation according to the "tank-pump-tank" scheme. The temperature of the circulating water should be around 60°C. The circulation time of the solution is 1 hour. The concentration of the inhibitor in the working solution is determined in accordance with the method of Appendix 1.

Rice. 3. Scheme of conservation of power boilers KI:

1 - inhibitor preparation tank with a capacity equal to the water volume of the boiler with a superheater; 2 - pump for filling the boiler with an inhibitor solution; 3 - drum boiler; 4 - feed water to the boiler; 5 - screens; 6 - make-up water; 7 - inhibitor;

8 - drainage tank pump; 9 - drainage tank; 10 - boiler drains, feed tract; 11 - deaerator: 12 - heating surface up to E; 13 - once-through boiler; 14 - from PND

Conservation pipelines

2.9.7. The previously emptied boiler is filled with the prepared inhibitor solution at a drum temperature not exceeding 60°C. Filling is carried out through the drains of the lower points of the screens and E with open air vents of the boiler.

The boiler drum is filled completely, through it the superheater. The air vents along the boiler path are closed as it is filled after the appearance of a continuous stream of solution.

When taking out for repair, in order to form a protective film on the metal, the preservative solution must be in the boiler for at least 24 hours, after which the solution is poured into the storage tank. If necessary, in the process of repairing the cutting of pipes of the non-draining stage of the superheater, the solution is first drained from other stages, from where the solution can enter the specified non-draining stage.

When cutting non-draining stage pipes, it is necessary to collect the drained solution and take the precautions for working with toxic substances.

2.9.8. During the downtime for conservation, water or steam must not be allowed to enter the boiler.

2.9.9. To depreserve the boiler after a downtime in the reserve, the inhibitor solution is drained from the boiler into the solution storage tank.

Since the inhibitor decomposes when the temperature rises, without giving potentially acidic products, the boiler is not specially washed, and kindling is carried out in accordance with the instructions for starting the boiler.

2.9.10. Contact inhibitor M-1 of repeated action, therefore, the solution drained from the boiler should be used for subsequent preservation of the boilers. It is only necessary to check the concentration of the solution and, if necessary, add some commercial inhibitor.

3. METHODS OF PRESERVATION OF DIRECT-FLOW BOILERS

3.1. Dry shutdown of the boiler

3.1.1. Dry shutdown is used on all once-through boilers, regardless of the adopted water chemistry.

3.1.2. Dry shutdown of the boiler is carried out during any scheduled and emergency shutdowns of the boiler for up to 30 days.

3.1.3. After the furnace is extinguished and the boiler is disconnected from the turbine, the shut-off valves on the supply pipelines are closed.

Steam from the boiler is partially discharged through the BROU (PSBU) into the condenser so that within 20-30 minutes the pressure in the boiler drops to 3-4 MPa, while the air intake remains open.

Open the drains of the inlet manifolds NRCH and E to displace water from the boiler with their own steam, while the SSBU (BROU) is closed.

After the pressure in the boiler is reduced to zero for 30 min, vacuum drying of the heating surfaces is carried out, for which purpose the SBU (BROU) is opened again. Then close the valves on the steam pipelines and on all lines connecting the boiler to the condenser.

The intermediate superheater is deevaporated to the condenser by opening the shut-off valves on the discharge lines from the hot steam pipelines. The vacuum in the system is maintained for at least 15 minutes.

When put into reserve, the ventilation of the gas-air path is carried out in accordance with the PTE, and during a shutdown for repairs - until the heating surfaces cool down.

3.2.1. Under the influence of a medium containing hydrazine, a protective oxide film is formed on the metal surface at high temperatures, which reliably protects the metal from corrosion for a long time.

The concentration of hydrazine during processing significantly exceeds the operational norm and depends on the duration of processing.

3.2.2. When treated with hydrazine at operating parameters, depending on the downtime, the content of hydrazine in the feed water is 0.3-3 mg/kg, and the duration of treatment is from 1-2 to 24 hours.

3.2.3. Hydrazine treatment is used on boilers in the hydrazine-ammonia or hydrazine mode.

3.2.4. The treatment is carried out in combination with CO when the boiler is taken into reserve for up to 3 months. or withdrawal to medium or major repairs.

During the processing period, the boiler operates in normal mode and carries the required load.

3.2.5. Dosing of hydrazine is carried out using a standard hydrazine unit on the suction side of the feed pumps or into the main condensate after the BOU.

Immediately before treatment in the measuring tank of the installation, a solution of the required concentration is prepared, taking into account the performance of the dosing pump and the expected load of the boiler.

3.2.6. Hydrazine treatment is carried out immediately before a planned shutdown. Depending on the downtime of the boiler, the approximate duration of treatment and the content of hydrazine in the feed water are:

During treatment, the hydrazine content is monitored by taking water samples from a sampling point on the feed water line upstream of the boiler.

At the end of the GO, SO is performed.

3.2.7. During the subsequent start-up of the boiler, it is also necessary to maintain a hydrazine content of 1-3 mg/kg in the feed water for 24 hours until the quality of the feed water stabilizes at a normalized level.

3.3.1. Processing is carried out to restore damaged protective films due to increased oxygen dosages compared to operational dosages. The oxygen content in the feed water increases to 1-2 mg/kg a few hours before the boiler shuts down.

3.3.2. Oxygen treatment is used on boilers for various modifications of the oxygen water regime.

3.3.3. The treatment is carried out in combination with CO when the boiler is taken into reserve for up to 3 months. or withdrawal to medium or major repairs.

During the processing period, the boiler operates in normal mode and carries the required load.

3.3.4. Processing is carried out using standard oxygen or air dosing units.

3.3.5. During the treatment period before the planned shutdown of the boiler, the oxygen content in the feed water increases to 1-2 mg/kg 8-10 hours before the shutdown.

During treatment, the oxygen content in the feed water before the boiler is controlled.

At the end of the specified time, CO is performed.

3.3.6. When starting up the boiler, it is also necessary to maintain an oxygen content of 1 mg/kg in the feed water for 30-40 hours until the quality of the feed water stabilizes at the normalized value.

3.4.1. Filling the boiler with nitrogen is carried out at excess pressure in the heating surfaces. During the conservation process, the nitrogen flow must provide a slight overpressure in the boiler.

3.4.2. Preservation with nitrogen is used on boilers of any pressure at power plants that have nitrogen from their own oxygen plants. In this case, the use of nitrogen at its concentration not lower than 99% is allowed.

3.4.3. Filling with nitrogen is carried out when the boiler is taken into reserve for a period of up to one year.

3.4.4. It is advisable to provide for the supply of nitrogen to the steam outlet pipeline from the expander at a pressure of 2.0 MPa and to the cold reheat lines.

The scheme for supplying nitrogen to the boiler must be made in accordance with clause 2.8.5.

3.4.5. After shutting down the boiler and reducing the pressure in it to 0.2-0.5 MPa, open the valves on the nitrogen supply lines to the expander.

Before filling with nitrogen, vacuum drying of the intermediate superheater is performed.

After cooling down the boiler, the pressure in it is maintained at the level of 5-10 kPa.

If an intermediate superheater is not switched off, it is constantly purged with nitrogen at an hourly flow rate equal to 10% of the volume of the purged circuit.

3.4.6. During the conservation period, measures are taken to identify possible gas leaks and eliminate them.

3.4.7. If it is necessary to carry out minor repairs, a short-term interruption of the gas supply to the boiler is possible.

3.5.1. Contact inhibitor M-1 creates a protective film on the metal, which remains even after draining the preservative solution (see clause 2.9.1).

3.5.2. To preserve the heating surfaces, the boiler is filled with an aqueous solution of an inhibitor with a concentration of 0.5-1.5%, depending on the downtime, composition and amount of deposits on the heating surfaces. The specific concentration of the inhibitor solution is established after a chemical analysis of the sediment composition.

3.5.3. Preservation of CI is used for any types of boilers, regardless of the applied water-chemical regime.

3.5.4. Conservation with M-1 inhibitor is carried out when the boiler is taken into reserve or repaired for a period of 1 month. up to 2 years.

3.5.5. The preparation of the preservative solution is carried out in accordance with paragraphs. 2.9.5 and 2.9.6.

The inhibitor solution from the preparation tank is fed into the deaerator.

It is also necessary to provide for the draining of the solution from the feed lines and the boiler after conservation into the storage tank using drainage tanks for this purpose.

3.5.6. Before conservation, the deaerator, feed pipelines, HPH on the water side and the boiler itself are drained.

The filling of the boiler, feed lines and HPH is carried out with a booster pump, controlling the filling with the help of air vents. When a continuous jet appears from the air vents along the medium, they are closed.

When idle in reserve, the boiler is left filled with a preservative solution, tightly closing all the shut-off valves on the boiler.

3.5.7. To depreserve the boiler, the preservative solution after being idle in the reserve is drained from the feed lines, HPH and the boiler into a storage tank for later use.

Special water washes from the preservative solution during kindling are not performed.

4. SELECTION OF METHODS OF PRESERVATION OF POWER BOILERS DEPENDING ON THE TYPE AND DURATION OF DOWNTIME

4.1. Methods for preservation of drum boilers are selected in accordance with the table below.

For shorter periods of downtime, it is allowed to use the methods offered for any longer period.

Each boiler must be provided not only with a method or methods that protect the previously formed protective film on the metal surface during conservation (CO, ID, ZShch, KI, A), but also a method or methods that form and restore this film (GRO or GV, TO. FV).

It is advisable to carry out hydrazine treatment at operating parameters not only before shutdown, but also in accordance with the PTE at any start-up of the boiler, if maintenance is not expected.

Duration

View

Preservation methods

shutdown

Boilers for pressure 3.9

Boilers for pressure 9.8 MPa

Boilers for pressure 13.8 MPa

MPa

Without feed water treatment with hydrazine

Feed water treatment with hydrazine

Recommended method

Possible replacement

Recommended method

Possible replacement

Recommended method

Possible replacement

Recommended method

Possible replacement

Recommended way

Possible replacement

Scheduled shutdown

Up to 10 days

Reserve

hydraulic fracturing

CO, ID

hydraulic fracturing

CO, ID

Repair

SO

-

SO

-

hydraulic fracturing

SO

-

hydraulic fracturing

SO

Up to 30 days

Reserve

DEF

SO

DEF

SO

Hydraulic fracturing + SO, GO

hydraulic fracturing, SO

DEF

SO

Hydraulic fracturing + SO, GO

hydraulic fracturing, SO

Repair

SO

-

SO

-

Hydraulic fracturing + SO, GO

hydraulic fracturing, SO

SO

-

Hydraulic fracturing + SO, GO

hydraulic fracturing, SO

Up to 60 days

Reserve

ZShch, KI, A

FV

ZShch, KI, A

THEN

GO, KI, A

Hydraulic fracturing + CO, maintenance, protection

ZShch, KI, A

THEN

GO, KI, A

Hydraulic fracturing + CO, maintenance, protection

Repair

FV, KI

-

TO, KI

FV

GO, KI

Fracturing + CO, TO

TO, KI

-

GO, KI

Fracturing + CO, TO

Up to 4 months

Reserve

KI, A

DEF

KI, A

DEF

KI, A

DEF

KI, A

DEF

KI, A

DEF

Repair

CI

FV

before - TO + KI, after - TO

MOT before and after

before - TO + KI, after - TO

MOT before and after

before - TO + KI, after - TO

MOT before and after; before - GO, hydraulic fracturing + CO, after - maintenance

Up to 6 months

Reserve

KI, A

FV+ZShch

KI, A

TO+ZSHCH

KI, A

TO+ZSHCH, GO+ZSHCH

KI, A

TO+ZSHCH

KI, A

THAT + SHCH GO + SHCH

Repair

CI

-

before - TO + KI, after - TO

MOT before and after

before - TO, after - KI+TO

MOT before and after

before - TO, after - KI+TO

MOT before and after

to - TO + KI, after - maintenance

MOT before and after

Over 6 months

Reserve

KI, A

-

KI, A

-

KI, A

-

KI, A

-

KI, A

-

Repair

CI

-

before - TO + KI, after - TO

-

before - TO + KI, after - TO

-

to - TO + KI, after - maintenance

-

before - TO + KI, after - TO

-

Emergency Stop

SO

-

SO

-

SO

-

SO

-

SO

-

CO - the first stage, further conservation depends on the subsequent repair period, reserve

Notes: 1. On boilers with a pressure of 9.8 and 13.8 MPa without treatment of feed water with hydrazine, maintenance should be carried out at least once a year.

2. A - filling the heating surfaces of the boiler with nitrogen.

3. Hydraulic fracturing + CO - hydrazine treatment at the operating parameters of the boiler, followed by a dry shutdown; GO+ZShch, TO+ZShch, FV+ZShch - filling the boiler with an alkaline solution with the previous reagent treatment;

4. TO + KI - conservation with a contact inhibitor with a previous trilon treatment;

5. "Before", "after" - before and after repair.

Hydrazine or oxygen treatment in combination with CO is performed when the boiler is placed on standby for up to 3 months. or repair for up to 5-6 months.

In the case of longer periods of reserve or repair, CI or nitrogen (A) should be used for conservation of the boilers.

When a once-through boiler is taken into reserve or repaired for a period of more than 1 month. it is advisable, if possible, to fill the condensate path and the deaerator with an ammonia solution, for which ammonia is dosed into the condensate downstream of the BOU by a standard pump 0.5-1 hour before shutdown to achieve a pH value downstream of the deaerator of at least 9.2.

4.3. In conditions of a sharp increase in the number and duration of downtime of power equipment in order to maintain all systems of the boiler (power unit), and not just heating surfaces, in working order, it is necessary to organize the operation of the power plant in such a way that the downtime of each boiler (power unit) in reserve does not exceed 3 months. , and upon reaching this period or earlier, depending on the specific situation, the boiler (energy unit) was put into operation and stopped in reserve by another.

4.4. When putting the boiler into standby for an indefinite period, the conservation method should be chosen, focusing on the maximum standby period typical for the practice of this power plant.

The concept of "indefinite period" implies a stop in the reserve for some, often short, period, followed by, possibly multiple, extension of the period.

4.5. When the boiler is put into reserve or repair (reconstruction) for a period of more than 5-6 months. it is necessary to develop a special technical solution taking into account specific conditions (boiler type, type and duration of downtime, available conservation equipment, contamination of internal heating surfaces), and also consider the feasibility of chemical cleaning of the boiler before conservation.

5. METHODS FOR PRESERVATION OF WATER BOILERS

5.1.1. The method is based on highly effective inhibitory abilities of Ca(OH) 2 calcium hydroxide solution.

The protective concentration of calcium hydroxide is 0.7 g/kg and above.

Upon contact with the metal of calcium hydroxide solution, a stable protective film is formed within 3-4 weeks.

When emptying the boiler from the solution after contact for 3-4 weeks. or more protective effect of the films is maintained for 2-3 months.

This method is regulated by "Guidelines for the use of calcium hydroxide for the conservation of heat and power and other industrial equipment at the facilities of the Ministry of Energy: RD 34.20.593-89" (M.: SPO Soyuztekhenergo, 1989).

5.1.2. When implementing this method, the boiler is completely filled with a solution. If repair work is required, the solution after exposure in the boiler for 3-4 weeks. can be drained.

5.1.3. Calcium hydroxide is used for the preservation of hot water boilers of all types at power plants with lime-based water treatment plants.

5.1.4. Conservation with calcium hydroxide is carried out when the boiler is taken into reserve for up to 6 months. or withdrawal for repair for up to 3 months.

5.1.5. The calcium hydroxide solution is prepared in wet lime storage cells with a floating suction device (Fig. 4). After pouring lime (fluff, building lime, calcium carbide slaking waste) into the cells and stirring, the milk of lime is allowed to settle for 10-12 hours until the solution is completely clarified. Due to the low solubility of calcium hydroxide at a temperature of 10-25°C, its concentration in solution will not exceed 1.4 g/kg.

When pumping the solution out of the cell, it is necessary to monitor the position of the floating suction device, avoiding the capture of sediments at the bottom of the cell.

5.1.6. To fill the boilers with a solution, it is advisable to use the scheme of acid washing of hot water boilers, shown in fig. 4. A tank with a pump for conservation of energy boilers can also be used (see Fig. 2).

Rice. 4. Scheme of preservation of hot water boilers:

1 - tank for the preparation of chemical reagents; 2 - pump for filling the boiler with a solution of chemical reagents; 3 - make-up water; 4 - chemical reagents; 5 - milk of lime in pretreatment mixers; 6 - cells of lime milk; 7 - hot water boilers;

8 - to other hot water boilers; 9 - from other hot water boilers;

Conservation pipelines

5.1.7. Before filling the boiler with a preservative solution, the water from it is drained.

Calcium hydroxide solution from lime cells is pumped into the reagent preparation tank. Before pumping, the pipeline is flushed with water to prevent lime milk supplied through this pipeline for pre-treatment of the water treatment plant from entering the tank.

It is advisable to fill the boiler when the solution is recirculated along the circuit "tank - pump - solution supply pipeline - boiler - solution discharge pipeline - tank". In this case, the amount of lime mortar prepared must be sufficient to fill the mothballed boiler and the recirculation circuit, including the tank.

If the boiler is filled with a pump from the tank without recirculation through the boiler, then the volume of prepared milk of lime depends on the water volume of the boiler.

The water volume of the boilers PTVM-50, PTVM-100, PTVM-180 is 16, 35 and 60 m 3 respectively.

5.1.8. When put into reserve, the boiler is left filled with solution for the entire downtime.

5.1.9. If it is necessary to carry out repair work, the drainage of the solution is carried out after exposure in the boiler for at least 3-4 weeks. in such a way that after the repair is completed, the boiler is put into operation. It is desirable that the duration of the repair does not exceed 3 months.

5.1.10. If the boiler is left with a preservative solution during the downtime, then it is necessary to check the pH value of the solution at least once every two weeks. To do this, organize the recirculation of the solution through the boiler, take samples from the air vents. If the pH value is ³ 8.3, the solution from the entire circuit is drained and filled with fresh calcium hydroxide solution.

5.1.11. Drainage of the preservative solution from the boiler is carried out at a low flow rate, diluting it with water to a pH value< 8,5.

5.1.12. Before start-up, the boiler is washed with network water to the hardness of the washing water, having previously drained it if it was filled with a solution.

5.2.1. Sodium silicate (liquid sodium glass) forms a strong, dense protective film on the metal surface in the form of Fe 3 O 4 × FeSiO 3 compounds. This film shields the metal from the effects of corrosive agents (CO 2 and O 2).

5.2.2. When implementing this method, the boiler is completely filled with a solution of sodium silicate with a concentration of SiO 2 in the preservative solution of at least 1.5 g/kg.

The formation of a protective film occurs when the preservative solution is kept in the boiler for several days or when the solution circulates through the boiler for several hours.

5.2.3. Sodium silicate is used for conservation of all types of hot water boilers.

5.2.4. Preservation with sodium silicate is carried out when the boiler is taken into reserve for up to 6 months. or taking the boiler out for repair for up to 2 months.

5.2.5. To prepare and fill the boiler with a sodium silicate solution, it is advisable to use the scheme of acid washing of hot water boilers (see Fig. 4). A tank with a pump for mothballing power boilers can also be used (see Fig. 2).

5.2.6. The sodium silicate solution is prepared with softened water, since the use of water with a hardness above 3 meq/kg can lead to sodium silicate flakes falling out of the solution.

A preservative solution of sodium silicate is prepared in a tank with water circulating according to the "tank-pump-tank" scheme. Liquid glass is poured into the tank through the hatch.

5.2.7. The approximate consumption of liquid commercial sodium silicate is not more than 6 liters per 1 m 3 of the volume of the preservative solution.

5.2.8. Before filling the boiler with a preservative solution, the water from it is drained.

The working concentration of SiO 2 in the preservative solution should be 1.5-2 g/kg.

It is advisable to fill the boiler when the solution is recirculated along the circuit "tank - pump - solution supply pipeline - boiler - solution discharge pipeline - tank". In this case, the required amount of sodium silicate is calculated taking into account the volume of the entire circuit, including the tank and pipelines, and not just the volume of the boiler.

If the boiler is filled without organization of recirculation, then the volume of the prepared solution depends on the volume of the boiler (see paragraph 5.1.7).

5.2.9. When put into reserve, the boiler is left filled with preservative solution for the entire downtime.

5.2.10. If it is necessary to carry out repair work, the drainage of the solution is carried out after exposure in the boiler for at least 4-6 days in such a way that after the completion of the repair, the boiler is put into operation.

The solution can be drained from the boiler for repair after circulation of the solution through the boiler for 8-10 hours at a speed of 0.5-1m/s.

The duration of the repair should not exceed 2 months.

5.2.11. If the boiler is left with a preservative solution during downtime, an excess pressure of 0.01-0.02 MPa is maintained in it with network water by opening the valve on the bypass at the boiler inlet. During the conservation period, samples are taken from the air vents once a week to control the concentration of SiO 2 in solution. When the concentration of SiO 2 is less than 1.5 g/kg, the required amount of liquid sodium silicate is added to the tank and the solution is recirculated through the boiler until the required concentration is reached.

5.2.12. The depreservation of the hot water boiler is carried out before it is kindled by displacing the preservative solution into the network water pipelines in small portions (by partially opening the valve at the outlet of the boiler) 5 m 3 / h for 5-6 hours for the PTVM-100 boiler and 10-12 hours for the boiler PTVM-180.

With open heat supply systems, the preservative solution must be expelled from the boiler without exceeding the MPC - 40 mg / kg SiO 2 in network water.

6. METHODS FOR PRESERVATION OF TURBO PLANTS

6.1.1. Purging the turbine plant with hot air prevents moist air from entering the internal cavities and the occurrence of corrosion processes. Especially dangerous is the ingress of moisture on the surface of the flow part of the turbine in the presence of deposits of sodium compounds on them.

6.1.2. Preservation of a turbine plant with heated air is carried out when it is put into reserve for a period of 7 days or more.

Preservation is carried out in accordance with the guidelines "Guidelines for the conservation of steam turbine equipment of thermal power plants and nuclear power plants with heated air: MU-34-70-078-84" (M.: SPO Soyuztekhenergo, 1984).

6.1.3. If the power plant does not currently have a conservation unit, it is necessary to use mobile fans with a heater to supply heated air to the turbine plant. Air can be supplied both to the entire turbine plant, and at least to its individual parts (LPC, LPC, boilers, to the upper or lower part of the condenser or to the middle part of the turbine).

To connect a mobile fan, it is necessary to provide for the installation of an inlet valve.

Recommendations MU 34-70-078-84 can be used to calculate the fan and intake valve.

When using mobile fans, drainage and vacuum drying measures specified in MU 34-70-078 should be carried out.

6.2. Preservation with nitrogen

6.2.1. When filling the internal cavities of the turbine plant with nitrogen and subsequently maintaining a small excess pressure, the ingress of moist air is prevented.

6.2.2. Filling is carried out when the turbine plant is taken into reserve for 7 days or more at those power plants where there are oxygen plants that produce nitrogen with a concentration of at least 99%.

6.2.3. For conservation, it is necessary to have a gas supply to the same points as air.

It should be taken into account the difficulties of sealing the flow part of the turbine and the need to ensure the nitrogen pressure at the level of 5-10 kPa.

6.2.4. The supply of nitrogen to the turbine is started after the turbine is stopped and the vacuum drying of the intermediate superheater is completed.

6.2.5. Preservation with nitrogen can also be applied to the steam spaces of boilers and heaters.

6.3.1. Volatile corrosion inhibitors of the IFKhAN type protect steel, copper, brass by being adsorbed on the metal surface. This adsorbed layer significantly reduces the rate of electrochemical reactions that cause the corrosion process.

6.3.2. To preserve the turbine plant, air saturated with the inhibitor is sucked through the turbine. Air is sucked through the turbine plant by means of a seal ejector or a starting ejector. Air is saturated with an inhibitor when it comes into contact with silica gel impregnated with an inhibitor, the so-called linasil. Linasil is impregnated at the factory. To absorb excess inhibitor at the outlet of the turbine, the air passes through pure silica gel.

Conservation with a volatile inhibitor is carried out when placed in reserve for a period of more than 7 days.

6.3.3. To fill the turbine with inhibited air, at its inlet, for example, to the pipeline for supplying steam to the front seal of the HPC, a cartridge with linasil is connected (Fig. 5). To absorb the inhibitor excess, cartridges with pure silica gel are installed at the outlet of the equipment, the volume of which is 2 times greater than the volume of linasil at the inlet. In the future, this silica gel can be additionally impregnated with an inhibitor and, during the next conservation, installed at the inlet to the equipment.

Rice. 5. Preservation of turbines with a volatile inhibitor:

1 - main steam valve; 2 - high pressure stop valve;

3 - high pressure control valve; 4 - protective valve of medium pressure;

5 - medium pressure control valve; 6 - chambers for suction of the steam-air mixture from the end seals of the cylinders; 7 - sealing steam chamber; 8 - sealing steam pipeline; 9 - existing valves; 10 - collector of steam-air mixture for seals; 11 - steam-air mixture suction manifold; 12 - inhibitor supply pipeline; 13 - cartridge with linasil; 14 - newly mounted gate valves; 15 - seal ejector; 16 - exhaust into the atmosphere; 17 - pure silica gel cartridges for inhibitor absorption; 18 - pipeline for suction of the steam-air mixture from the chambers; 19 - intermediate superheater; 20 - air sampling; 21 - flange; 22 - valve

To fill the turbine with inhibited air, standard equipment is used - a seal ejector or a starting ejector.

For conservation of 1 m 3 volume, at least 300 g of linasil is required, the protective concentration of the inhibitor in the air is 0.015 g/dm 3 .

Linasil is placed in cartridges, which are pipe sections, to both ends of which flanges are welded. Both ends of the pipe with flanges are tightened with a mesh with a mesh size that does not allow spillage of linasil, but does not interfere with the passage of air. The length and diameter of the pipes is determined by the amount of linasil required for conservation.

Linasil is loaded into cartridges with a spatula or gloved hands.

6.3.4. Before the start of conservation, to exclude possible accumulation of condensate in the turbine, pipelines and valves, they are drained, the turbine and its auxiliary equipment are devaporated, disconnected from all pipelines (drains, steam extractions, steam supply to seals, etc.).

To remove possible accumulation of condensate in non-drained areas, the turbine is dried with air. To do this, a cartridge with calcined silica gel is installed at the inlet and air is sucked in by an ejector along the circuit "cartridge - HPC - CSD - LPC - manifold for suction of the vapor-air mixture from the seals - ejector - atmosphere".

After the turbine metal has cooled to approximately 50°C, it is sealed with asbestos packing impregnated with sealant at the air inlet from the turbine hall to the suction chamber of the vapor-air mixture of the end seals.

After drying the turbine, cartridges with linasil are installed at the inlet, and cartridges with pure silica gel are installed at the outlet, the ejector is switched on and air is sucked in along the circuit "cartridge-pipeline for supplying steam to the seal - HPC - vapor-air mixture suction manifold - cartridges with silica gel - ejector - atmosphere". Upon reaching a protective inhibitor concentration equal to 0.015 g/dm 3 , conservation is terminated, for which the ejector is turned off, a plug is installed at the air inlet into the cartridge with linasil and at the inlet of inhibited air into the cartridges with silica gel.

6.3.5. During the period when the turbine is in reserve, the concentration of the inhibitor in it is determined monthly (Appendix 2).

When the concentration falls below 0.01 g/DM 3 carry out re-preservation with fresh linasil.

6.3.6. To depreserve the turbine, the cartridges with linasil are removed, the plug at the inlet of the inhibited air into the cartridge with silica gel, the ejector is turned on, and the inhibited air is drawn through the silica gel to absorb the remaining inhibitor for the same time that it took to preserve the turbine.

Since the conservation is carried out in a closed circuit, there are no effluents or emissions into the atmosphere.

Brief characteristics of the chemicals used are given in Appendix 3.

Attachment 1

METHOD FOR DETERMINING THE CONCENTRATION OF CONTACT INHIBITORS IN WORKING SOLUTION

When the inhibitor is dissolved in a pure condensate, the alkalinity of the solution will be due only to cyclohexylamine. Minor amounts of ammonia, often present in condensates, can be ignored, since the ammonia content usually does not exceed 0.5-0.8 mg/kg (alkalinity from 0.003 to 0.047 meq/kg). As a consequence, the alkalinity can simply be titrated in the presence of methyl red.

A measured portion of a solution of 100 cm 3 in a conical flask is titrated with 3-5 drops of an indicator with a solution of sulfuric acid with a molar concentration of the equivalent of 0.1 mol/dm 3 until the color of the liquid changes from yellow to red.

FROM 1 = BUT × to× 0.0099 × 10,

where BUT- acid consumption for titration, cm 3;

to- correction factor of acid to exactly decinormal concentration;

0.0099 - cyclohexylamine conversion factor;

10 - recalculation of the concentration of hexylamine in dm 3.

where 0.32 is the content of cyclohexylamine in the inhibitor (according to passport data);

0.1 - conversion of grams in decimeter to mass percent.

Annex 2

DETERMINATION OF THE CONCENTRATION OF A FLYING INHIBITOR IN THE AIR

1. Used reagents:

hydrochloric acid, chemically pure concentration 0.01 mol/kg;

sodium hydroxide, chemically pure concentration 0.01 mol/kg;

mixed indicator.

2. Determination of concentration

Through a bottle containing 0.1 kg of a solution of hydrochloric acid with a concentration of 0.01 mol/kg, using an aspirator, 5 kg of air containing an inhibitor is slowly passed; which is absorbed by the acid solution, after which 10 cm 3 of the acid solution are taken and titrated with sodium hydroxide with a mixed indicator.

where V- volume of passed air, dm 3 ;

k 1 , k 2 - respectively, correction factors for solutions of acid and alkali, having a molar concentration of equivalents of exactly 0.01 mol/dm 3 ;

but- consumption of an alkali solution with a molar concentration equivalent of 0.01 mol / dm 3 for titration of the remaining acid, cm 3

M- molecular (equivalent) weight of the inhibitor, equal to IFKhAN-1 - 157; IFKHAN-100 - 172.

Appendix 3

SUMMARY OF CHEMICALS USED AND PRECAUTIONS FOR THEIR HANDLING

Toxicity (hazard class) used for the preservation of reagents:

hydrazine - 1;

caustic soda MSDA and IFKhAN-1 - 2;

M-1, IFKHAN-100 - 3;

ammonia - 4.

1. An aqueous solution of hydrazine hydrate N 2 H 4 × H 2 O

A solution of hydrazine hydrate is a colorless liquid that easily absorbs water, carbon dioxide and oxygen from the air. Hydrazine hydrate is a strong reducing agent.

Aqueous solutions of hydrazine with a concentration of up to 30% are non-flammable; they can be transported and stored in carbon steel vessels.

When working with solutions of hydrazine hydrate, it is necessary to exclude the ingress of porous substances and organic compounds into them.

Hoses should be connected to the places of preparation and storage of hydrazine solutions to flush the spilled solution from the floor and equipment with water. For neutralization and neutralization, bleach must be prepared.

If repairs are required on equipment used for the preparation and dosing of hydrazine, it should be thoroughly rinsed with water.

The solution of hydrazine that has fallen on the floor should be covered with bleach and washed off with plenty of water.

Aqueous solutions of hydrazine can cause skin dermatitis, its vapors irritate the respiratory tract and eyes. Hydrazine compounds, entering the body, cause changes in the liver and blood.

When working with hydrazine solutions, it is necessary to use goggles, rubber gloves, a rubber apron and a KD brand gas mask.

Drops of hydrazine solution that come into contact with the skin and eyes should be washed off with plenty of water.

2. An aqueous solution of ammonia NH 4 (OH)

An aqueous solution of ammonia (ammonia water) is a colorless liquid with a sharp specific odor. At room temperature, and especially when heated, ammonia is abundantly released. The maximum permissible concentration of ammonia in the air is 0.02 mg/dm 3 . Ammonia solution is alkaline.

Ammonia solution should be stored in a tank with a sealed lid.

Spilled ammonia solution should be washed off with plenty of water.

If repairs are required on equipment used for the preparation and dosing of ammonia, it should be thoroughly rinsed with water.

Aqueous solution and ammonia vapor cause irritation of the eyes, respiratory tract, nausea and headache. It is especially dangerous to get ammonia in the eyes.

Protective goggles must be worn when working with ammonia solution.

Ammonia that has come into contact with the skin and eyes must be washed off with plenty of water.

3. Trilon B

Commercial Trilon B is a white powdery substance.

Trilon solution is stable, does not decompose during prolonged boiling. The solubility of Trilon B at a temperature of 20-40°C is 108-137 g/kg. The pH value of these solutions is about 5.5.

Commodity Trilon B is supplied in paper bags with a polyethylene liner. The reagent must be stored in a closed, dry place.

Trilon B does not have a noticeable physiological effect on the human body.

When working with commodity Trilon, it is necessary to use a respirator, gloves and goggles.

4. Trisodium phosphate Na 3 PO 4 × 12 H 2 O

Trisodium phosphate is a white crystalline substance, highly soluble in water.

In a crystalline form, it does not have a specific effect on the body.

In a dusty state, getting into the respiratory tract or eyes, irritate the mucous membranes.

Hot phosphate solutions are dangerous if splashed into the eyes.

When carrying out work accompanied by dusting, it is necessary to use a respirator and goggles. Use goggles when working with hot phosphate solution.

In case of contact with skin or eyes, rinse with plenty of water.

5. Caustic soda NaOH

Caustic soda is a white, solid, very hygroscopic substance, highly soluble in water (at a temperature of 20 ° C, 1070 g / kg dissolves).

Caustic soda solution is a colorless liquid heavier than water. The freezing point of a 6% solution is minus 5 ° C, 41.8% - 0 ° C.

Caustic soda in solid crystalline form is transported and stored in steel drums, and liquid alkali - in steel containers.

Caustic soda (crystalline or liquid) that has fallen on the floor should be washed off with water.

If it is necessary to repair the equipment used for the preparation and dosing of alkali, it should be washed with water.

Solid caustic soda and its solutions cause severe burns, especially if it comes into contact with the eyes.

When working with caustic soda, it is necessary to provide a first aid kit containing cotton wool, a 3% solution of acetic acid and a 2% solution of boric acid.

Personal protective equipment when working with caustic soda: cotton suit, goggles, rubberized apron, rubber boots, rubber gloves.

If alkali gets on the skin, it must be removed with cotton wool, rinse the affected area with acetic acid. If alkali gets into the eyes, rinse them with a stream of water, and then with a solution of boric acid and contact the first-aid post.

6. Sodium silicate (liquid glass sodium)

Commodity liquid glass is a thick solution of yellow or gray color, the content of SiO 2 is 31-33%.

Comes in steel barrels or tanks. Liquid glass should be stored in dry enclosed spaces at a temperature not lower than plus 5°C.

Sodium silicate is an alkaline product, readily soluble in water at a temperature of 20-40°C.

If a liquid glass solution comes into contact with the skin, it should be washed off with water.

7. Calcium hydroxide (lime mortar) Ca (OH) 2

Lime mortar is a clear, colorless and odorless liquid, non-toxic and slightly alkaline.

A solution of calcium hydroxide is obtained by settling milk of lime. The solubility of calcium hydroxide is low - no more than 1.4 g/kg at 25°C.

When working with lime mortar, people with sensitive skin are advised to wear rubber gloves.

If the solution gets on the knife or in the eyes, wash it off with water.

8. Contact inhibitor

Inhibitor M-1 is a salt of cyclohexylamine (TU 113-03-13-10-86) and synthetic fatty acids of fraction C 10-13 (GOST 23279-78). In its commercial form, it is a pasty or solid substance from dark yellow to brown. The melting point of the inhibitor is above 30°C; mass fraction of cyclohexylamine - 31-34%, pH of an alcohol-water solution with a mass fraction of the main substance of 1% - 7.5-8.5; the density of an aqueous solution of 3% at a temperature of 20 ° C is 0.995-0.996 g / cm 3.

Inhibitor M-1 is supplied in steel drums, metal flasks, steel barrels. Each package must be marked with the following data: name of the manufacturer, name of the inhibitor, batch number, date of manufacture, net weight, gross weight.

Commercial inhibitor refers to combustible substances and must be stored in a warehouse in accordance with the rules for the storage of combustible substances. An aqueous solution of the inhibitor is not flammable.

The inhibitor solution that has fallen on the floor must be washed off with plenty of water.

If it is necessary to repair the equipment used to store and prepare the inhibitor solution, it should be thoroughly rinsed with water.

The M-1 inhibitor belongs to the third class (moderately hazardous substances). MPC in the air of the working area for the inhibitor - 10 mg/m 3 .

The inhibitor is chemically stable, does not form toxic compounds in the air and wastewater in the presence of other substances or industrial factors.

Persons involved in work with an inhibitor must have a cotton suit or dressing gown, gloves, and a headgear.

Wash your hands with warm water and soap after finishing work with the inhibitor.

9. Volatile inhibitors

9.1. Volatile atmospheric corrosion inhibitor IFKhAN-1 (1-diethylamino-2-methylbutanone-3) is a transparent yellowish liquid with a sharp specific odor.

Liquid inhibitor IFKhAN-1 refers to highly hazardous substances according to the degree of exposure, MPC of inhibitor vapors in the air of the working area is 0.1 mg/m 3 . Inhibitor IFKhAN-1 in high doses causes excitation of the central nervous system, irritating effect on the mucous membranes of the eyes, upper respiratory tract. Prolonged exposure of the inhibitor to unprotected skin may cause dermatitis.

The IFKhAN-1 inhibitor is chemically stable and does not form toxic compounds in the air and wastewater in the presence of other substances.

Liquid inhibitor IFKhAN-1 refers to flammable liquids. The ignition temperature of the liquid inhibitor is 47°C, the autoignition temperature is 315°C. In case of fire, fire extinguishing agents are used: felt mat, foam fire extinguishers, OS fire extinguishers.

Cleaning of premises should be carried out in a wet way.

When working with the IFKhAN-1 inhibitor, it is necessary to use personal protective equipment - a suit made of cotton fabric (robe), rubber gloves.

9.2. The inhibitor IFKhAN-100, which is also a derivative of amines, is less toxic. Relatively safe exposure level - 10 mg/m 3 , ignition temperature - 114°С, self-ignition - 241°С.

Safety measures when working with the IFKhAN-100 inhibitor are the same as when working with the IFKhAN-1 inhibitor.

It is forbidden to carry out work inside the equipment until it is depreserved.

At high concentrations of the inhibitor in the air or if it is necessary to work inside the equipment after its depreservation, a grade A gas mask with a grade A filter box (GOST 12.4.121-83 and GOST 12.4.122-83) should be used. The equipment must be ventilated beforehand. Work inside the equipment after depreservation should be carried out by a team of two people.

After finishing work with the inhibitor, wash your hands with soap and water.

In case of contact with the liquid inhibitor on the skin, wash it off with soap and water, in case of contact with the eyes, rinse them with a plentiful stream of water.

1. General Provisions

2. Methods for preservation of drum boilers

2.1. Dry shutdown of the boiler

2.2. Maintaining excess pressure in the boiler

2.3. Hydrazine treatment of heating surfaces at operating parameters of the boiler

2.4. Hydrazine treatment (HT) of heating surfaces at reduced boiler parameters

2.5. Trilon treatment of boiler heating surfaces

2.6. Phosphate-ammonia "boil-out"

2.7. Filling the heating surfaces of the boiler with protective alkaline solutions

2.8. Filling the heating surfaces of the boiler with nitrogen

2.9. Preservation of the boiler with a contact inhibitor

3. Methods of conservation once-through boilers

3.1. Dry shutdown of the boiler

3.2. Hydrazine treatment of heating surfaces at operating parameters of the boiler

3.3. Oxygen treatment of heating surfaces at boiler operating parameters

3.4. Filling the heating surfaces of the boiler with nitrogen

3.5. Preservation of the boiler with a contact inhibitor

4. Choice of conservation methods for energy boilers depending on the type and duration of downtime

5. Methods of preservation of hot water boilers

5.1. Preservation with calcium hydroxide solution

5.2. Preservation with sodium silicate solution

6. Methods for conservation of turbine plants

6.1. Preservation with heated air

6.2. Preservation with nitrogen

6.3. Preservation with volatile corrosion inhibitors

Annex 1. Method for determining the concentration of contact inhibitors in the working solution

Annex 2. Determination of the concentration of a volatile inhibitor in the air

Annex 3. Brief characteristics of the chemicals used and precautions when working with them