An equipment conservation act is a document drawn up by the commission in a free form, which confirms that all the objects listed in it are subject to suspension of operation for a certain period with the possibility of its resumption in the future.

FILES

Main reasons for conservation

There are three reasons why equipment is mothballed:

1. Temporary cessation of commercial and non-commercial activities.
2. Production volume began to decline.
3. Inappropriate use of equipment.

Reasons for equipment conservation

Equipment conservation is carried out due to the following circumstances:

• man-made accidents, natural and man-made disasters that caused the cessation of equipment operation;
• non-use of equipment for more than three months in a row;
• the inability to repurpose equipment due to its specific features;
• equipment cannot be rented out;
• equipment used seasonally in commercial and non-commercial activities.

Who decides to mothball equipment?

The fundamental decision to “freeze” rests with the director of the company. He also confirms with his signature the order of further actions. To create a list of equipment that is subject to conservation, you need to go through an inventory. For this purpose, the director, by order, appoints a commission responsible for the long-term preservation of the equipment. Then he issues a direct order on conservation.

Information that must be present in the document

The act must contain the following information:

• date of transfer of equipment for conservation;
• list of equipment that needs to be transferred;
• initial cost of equipment;
• reason for transfer;
• actions that were performed for the transfer;
• the amount of upcoming expenses;
• residual value if conservation is planned for more than three months;
• the amount of expenses already incurred;
• preservation period.

During the inventory count, equipment that is intended for canning is allocated by the commission to a separate group. To account for it, the subaccount “Objects transferred for conservation” is used. Such equipment is registered in the act, indicating the manufacturer, model name and inventory number.

Who signs and why is the equipment conservation act needed?

The act is signed by all members of the commission and approved by the director of the organization. It is necessary for the director in order to:

• pay less income tax;
• suspend depreciation charges on equipment placed in storage for more than three months;
• exercise control over the outflow of financial assets during the conservation period.

Preservation period

By law, the minimum period for equipment preservation is three months, and the maximum is three years. Calculation begins from the date of approval of the document. If there is a need to extend the period, then the proposal for extension must be put forward no later than a month before the expiration of the conservation period. As for the re-preservation of equipment, the proposal is made no earlier than five months after re-preservation (resumption of operation of previously mothballed equipment).

Typical mistakes when filling out a document

Since the document does not have a single form, it is drawn up in any form. True, the practice of tax and audit audits shows that accountants, when filling out documents, systematically make mistakes. Here are the most basic ones:

• errors in writing words and numbers (in calculations);
• adding text;
• notes made in pencil;
• different ink colors;
• unspecified date of document preparation;
• the name of the organization is incorrectly indicated;
• the fact of economic or production activity has not been deciphered;
• signing a document by a person acting on someone else’s behalf without authority or in excess of the authority granted;
• conspicuous mechanical impact on the document (artificial aging, masking part of the text);
• the act was drawn up on sheets of varying quality.

Of course, all of the above errors cannot indicate the invalidity of the document. It is quite possible that such filling was due to objective reasons.

Important! The Federal Tax Service Inspectorate will always show interest in such documents, as it will consider them to be improperly executed. This means that the tax service will refuse to reimburse the organization for VAT and reduce the taxable base of the direct tax levied on the organization’s profits.

Error correction

If an accounting specialist notices an error in the act, he has the right to correct it. For example, if an amount was entered incorrectly in a document, it can be edited by crossing it out and indicating the correct value. However, do not forget that corrections in the document must be certified correctly. For this it is enough:

• put in the act the date when the correction was made;
• write “Corrected Believe”;
• sign the employee who is responsible for the correction;
• decipher this signature.

When filling out a document, it is unacceptable to use line corrections, blots, corrections and erasures.

Conclusion

So, today many firms, companies, enterprises are forced to suspend their work for various reasons and introduce conservation of equipment that is little used or not used at all. Firstly, this procedure allows you to ensure the best safety of the equipment, and secondly, the company will greatly save money associated with the transfer of tax fees. A properly drafted conservation act can help those firms, companies, and enterprises that do not plan to complete the current financial year with a profit.

Water heating boilers KVR.

1. INTRODUCTION

The technical description is a guide for the installation, operation and transportation of the ASK Group of Companies water heating boiler. Contains information about the boiler design.

2 . PURPOSE

A hot water boiler with a heating capacity of 0.688 Gcal/hour is designed to heat water up to 95 0 C, intended for heating systems in residential, industrial and warehouse premises with a total area of ​​up to 8000 m 2 . Simultaneously with the boiler, a heater can be used to produce hot water used for domestic and industrial purposes to be discharged.

The water-tube boiler creates natural circulation of water in the heating system, in which you need to have an open expansion tank at the top point. When using a circulation pump creating a pressure of up to 6.0 kg/cm 2 , the heating system is made closed using a safety valve at the outlet of the boiler.

The boiler is designed for layer combustion of any type of solid fuel (wood, coal, peat). AtWhen installing the boiler in a specially equipped room, using additional devices, combustion of liquid and gaseous fuels (clarified kerosene, diesel fuel, diesel oil, natural or liquefied gas) is allowed.

The high degree of softness of the water used creates conditions for long-term operation of the boiler and heating system. From the outside, the boiler pipe system is thermally insulated with mineral wool and sheathed with a casing made of 2 mm thick steel sheet.

Installation of the hot water boiler and heating system should be carried out in accordance with the heating scheme of the building. To ensure normal circulation in horizontal areas, it is necessary to create a slope of at least 0.01 0 hot water pipelines from the highest point, with a decrease to the heating elements, and the slope of the return water pipeline with a decrease to the boiler.

3. TECHNICAL DATA

Basic technical data and parameters of the hot water boiler.

4. PRODUCT COMPOSITION

The product includes an all-welded design of the boiler pipe system block. The boiler is thermally insulated with mineral wool, covered with a casing, and equipped with three doors: firebox, ash pan and ash pan. Pressure gauges and thermometers, five grate bars, safety valves.

Installation, lining and adjustment work can be carried out at the request of the customer, by a visiting team of the enterprise, at the boiler installation site.

By agreement with the customer, the boiler can be equipped with furnace tools and auxiliary equipment

5. STRUCTURE AND OPERATION OF THE BOILER

5.1 Boiler design

The boiler is a transportable, non-dismountable block in the form of a firebox and a convective part, installed on an ash pan block (Fig. 1). At the bottom of the boiler there is a belt of collectors (longitudinal Ø159x5, transverse Ø133x5 mm), to which water cooled in the heating system is supplied through a DN 100 supply pipe. 5 grates measuring 900x220 mm are placed inside the lower belt of the collectors.

The boiler firebox is a closed volume, shielded by walls made of pipes Ø51x2.5mm.

In the front part of the firebox there is a door measuring 400x400 mm. Under the firebox, in the ash pan block, there is an ash pan with a door measuring 400x400mm and a blow air input window measuring 250x250mm.

The convective part of the boiler is made in the form of downward and upward flue ducts, each of which has 12 sections. Riser pipes Ø83x4 mm, convection pipes Ø51x2.5mm.

The flue ducts of the convective part are separated from the firebox and betweenconsisting of two-light gas-tight walls (4x30mm strip). Under the convective block, in the block, there is an ash pan, which has a door measuring 400x400 mm on the left or right side. In the upper part of the boiler there is an upper belt of collectors made of pipes (longitudinal Ø159x5, transverse Ø133x5) with 4 sling eyes. The boiler ceiling is shielded with pipes Ø83x4mm, embedded in a collecting manifold Ø133x5mm from which hot water is discharged through a DN100 pipe, and then into the heating system of the building.

On the outside, a 4x30 mm strip is welded between the pipes. The entire pipe system of the boiler is lined with heat-insulating mats made of basalt wool and sheathed with a casing made of 2 mm sheet.

Water flows through the shielding walls and elements of the boiler in accordance with the circulation scheme.

5.2 Operation of the hot water boiler

5.2.1. The flue gases, having reached the top of the firebox, turn 180 O and through the convective part are directed into the flue, from where they enter the chimney of the boiler room.

5.2.2. Water enters the boiler through the inlet pipeline. It is possible to install a mixing water pump, which is installed between the direct and return water supply. With the help of a mixing pump, the temperature of the return water entering the boiler rises to 60°C.Water is discharged from the boiler through the outlet pipeline.

5.2.3. Construction and operation of instrumentation and automation according to the documentation supplied with the kit.

6. CONTROL AND MEASURING INSTRUMENTS

An indicating pressure gauge and thermometer are installed on the return water pipe.

A pressure gauge is installed on the direct water inlet pipe.

7. PLACEMENT AND INSTALLATION

7.1. The boiler must be installed in separate rooms that meet the requirements of SNiP 2.01.02-85

7.2 Installation of the boiler must be carried out in accordance with the “Rules for the design and safe operation of steam boilers with a steam pressure of no more than 0.7 kgf/cm 2 : hot water boilers and water heaters with water heating temperature not exceeding 115 °C” and according to the boiler room design.

7.3 During installation, care should be taken to ensure that the boiler is installed strictly horizontally to the boiler room floor level.

8. TRANSPORTATION AND STORAGE

8.1. Boilers can be transported by any type of transport in compliance with measures to ensure their safety.

8.2. The boiler may only be lifted using the lifting eyes installed for this purpose. When lifting and installing, special care must be taken to avoid dropping or shaking the boiler so as not to damage the lining or insulation of the boiler.

The conditions for transportation and storage of boilers must comply with the requirements of group 5 of GOST 15150-69.

8.3. Storing boilers for 1 to 3 months is considered short-term. Over 3 months - long-term.

8.4. Short-term storage is allowed under enclosing structures that protect the boiler from precipitation.

8.5. Long-term storage should be carried out in special premises that must meet the following requirements:

the premises must be dry, ventilated, and protect the boiler from precipitation;

positive temperatures are maintained in the premises in winter;

The dimensions of the room ensure free placement of the boilers.

8.6. During storage, the outer surfaces of boilers must be cleaned of dirt, washed and dried.

8.7. Clean boiler flues from contamination. Drain the water completely. After draining the water, dry the inside of the boiler.

9. STARTING AND STOPPING THE BOILER

At the same time, in order to avoid the formation of condensation in the heat exchange elements, the initial start-up of the boiler and its transition from a cold to a hot state must occur slowly. The recommended heating rate of water in the boiler should not exceed 1+1.5 °C/min.

When starting the boiler after a short period of inactivity, the boiler load and water heating temperature can be increased somewhat faster, but not more than 2 °C/min.

If these requirements are violated during the initial start-up of the boiler, condensation may form in the heat exchange elements.

9.1. Stopping the boiler in all cases, with the exception of an emergency stop, must be carried out only with a written order from the administration.

When stopping the boiler you must:

Stop fuel supply to the firebox;

Disconnect the boiler from the pipeline after combustion in the furnace stops. If, after disconnecting the boiler from the pipeline, the pressure in the boiler increases, replenish the boiler and purge;

Cool down the boiler and drain water from it;

Ventilate the firebox and flue for 10-15 minutes, turn off the pump and vent;

De-energize the voltage shield;

It is prohibited to drain water from the boiler without the order of the person responsible for the good condition and safe operation of the boiler room. The drainage of water should be carried out slowly; the pipe part should communicate with the atmosphere using an air collector and a three-way pressure gauge valve.

The procedure for preserving a stopped boiler must comply with the instructions in these instructions.

To stop the boiler for a short time, there is no need to interrupt the water circulation.

Despite the fact that the necessary technological equipment is installed in the boiler room, and all the necessary measures for the preparation of boiler water have been carried out, however, during long-term operation, due to the lack of proper control on the part of the operating organizations over the operation of the water treatment equipment, solids are formed on the internal walls of the boiler heat exchange elements deposits in the form of scale. To remove scale, boilers are chemically cleaned. Chemical cleaning of boilers is carried out using alkalis or acids (trisodium phosphateNa 3 P.O. 4. sodium hydroxide NaOH, hydrochloric acidHCL).

Cleaning with trisodium phosphate is carried out in the following sequence:
The boiler is disconnected from the heating network, the water pressure in the boiler is reduced to 0.5 Atm and chemicals are introduced into the boiler from a special tank. reagents trisodium phosphate at the rate of 1.5 kg per 1 m 3 boiler water, turn on the mixing pump. After 2 hours, part of the boiler water is drained into the drainage and additional trisodium phosphate is introduced at the rate of 0.75 kg per 1 m 3 boiler water. The mixing pump is turned on again to circulate water in the boiler and the boiler is “boiled down” for 5-6 hours, while it is necessary to monitor the temperature and pressure of the water in the boiler, after which the boiler is cooled, the water is drained, the boiler is washed and filled with chemically purified water.

Acid cleaning of boilers is most effective in removing scale, compared to alkaline cleaning. But since acid washing is classified as a hazardous type of work, its implementation can only be entrusted to organizations licensed for this type of activity.

9.2 Emergency stop of the boiler

9.2.1. The boiler must be immediately stopped and disabled by protection or personnel in the following cases:

Safety valve malfunction detection;

If cracks, bulges, or gaps in welds are found in the main elements of the boiler;

Reducing water flow through the boiler below the minimum permissible value;

Reducing the water pressure in the hydraulic circuit of the boiler below the permissible level;

The pressure has risen above the permitted limit by 10% and continues to rise, despite the cessation of fuel supply and increased water supply to the boiler;

The feed pump has stopped working;

The power supply has been interrupted, and the boiler elements have been damaged, creating a danger for operating personnel or the threat of destruction of the boiler;

Malfunctions of automatic safety or alarm systems, including loss of voltage in these areas;

A fire occurs in the boiler room that threatens personnel or the boiler.

9.2.2. The procedure for emergency shutdown of the boiler must be specified in the production instructions. The reasons for the emergency shutdown of the boiler must be recorded in the shift log.

10. OPERATION AND MAINTENANCE

10.1 Operating procedure

After installing the boiler and connecting it to the space heating system, it is necessary to fill the system and boiler with water and carry out an inspection. The grate bars are installed after hydraulic testing and inspection.

When lighting the boiler, perform the following work:

1. open the chimney damper, firebox and ash door;

2. remove slag and ash from the firebox and from the ash pit;

3. put the required amount of firewood into the firebox on the grates;

4. Place lump coal on the firewood;

5. light firewood in the firebox;

6. close the firebox door and adjust the supply of the blower fan or the opening of the blower door according to combustion;

7. When burning wood and coal is stable, add the required amount of coal evenly throughout the firebox.

10.2 Maintenance

10.2.1 Maintenance consists of periodic inspections, blowing, cleaning of the boiler and its repair.

10.2.2 List of maintenance activities.

In order to ensure reliable operation of the hot water boiler, it is recommended to carry out the following measures:

Visual inspection of leaks;

Checking the drainage pipe;

Checking flange connections;

Blowing;

Complete cleaning, checking heating surfaces.

10.3 Blowing and cleaning the boiler

10.3.1. In order to ensure flawless and more economical operation of the boiler, blowing should be done quite often. When the flue gas temperature increases by 30-40 O With a higher gas temperature of a clean boiler at the same load, the boiler should be blown. Blowing the boiler should also be carried out if the resistance of the boiler gas path increases significantly.

10.3.2. The boiler is cleaned from soot through the doors of the firebox and ash pan. Cleaning can be done either manually or with a mechanized brush (brush). When cleaning with a power brush, care must be taken to avoid damaging the pipes.

10.3.3. Internal inspection and cleaning of the firebox is carried out during the summer shutdown of the boiler. All accumulated soot and dirt are removed from the walls of the firebox and convective part using a steel brush.

10.3.4. Internal inspection, flushing and cleaning of the water path should be carried out annually during the summer period of boiler downtime. Inspect the boiler through the firebox and ash pan doors.

The boiler is cleaned of boiler stone and sludge using a chemical method. Chemical cleaning is carried out with a 5% solution of hydrochloric acid, inhibited by a mixture of PB-5 - 0.1% with hexamine - 0.5%; or a mixture of PB-5 with urotropine and OP-10 at a temperature of 60-65°C. The circulation time of the solution is from 6 to 8 hours at a speed along the path of 1-1.5 m/sec.

After cleaning, flush the boiler by removing all deposits of dissolved scale and sludge from it through the lower drain pipe. After which it is necessary to fill the boiler with treated water as quickly as possible. If such a composition is not available, the boiler should be heated to operating temperature and aerated effectively.

10.4 Boiler repair

Repairs to the boiler during the warranty period can only be carried out with the written permission of the manufacturer.

After the warranty period, boiler repairs can only be carried out by a company that has the technical means necessary to perform the work efficiently.

10.5 Safety precautions

10.5.1. Strict adherence to safety precautions is required during maintenance. Repair work must be carried out in strict accordance with the norms and rules for the production of repair work.

10.5.2. Repairs, cleaning and inspection of the boiler may only be carried out after appropriate instruction at the workplace.

10.5.3. Work inside the boiler can only be carried out when the boiler is sufficiently cooled. Before starting work, the boiler must be ventilated.

10.5.4. It is prohibited to work in the firebox and convective part with a temperature above 60°C.

10.5.6. Boiler repairs should be carried out with water and air turned off, and power removed from the automation system.

10.5.7. Inspection, lubrication and repair of component equipment is carried out in accordance with the operating instructions for the relevant products.

10.5.8. Do not allow burning coal to fall onto the floor. The distance from the boiler to combustible structures must be at least 2000 mm.

10.5.9. It is unacceptable to leave firewood, coal, flammable objects or dry clothes near a lit boiler.

10.5.11. It is prohibited to use flammable fuel or explosive substances (gasoline, kerosene, acetone, etc.) to light the boiler.

10.5.12. When the boiler is running, the water temperature must not rise above 100 0 C, when the temperature rises, it is necessary to reduce fuel combustion by closing the blower fan gate or the blower door and reducing the draft or increasing the water flow.

11. PRESERVATION OF THE WATER BOILER

The procedure for preserving the boiler for long-term storage must comply with these instructions.

Preservation of the boiler for a period of up to one month should be carried out using the wet method, for this it is necessary:

Stop the boiler according to the instructions;

Disconnect the boiler pipeline from the general lines;

Fill the internal volume of the boiler with a protective solution: sodium hydroxide 1000 mg/l, phosphoric anhydride 100 ml/l and sodium sulfate 200 mg/l;

Before starting a boiler that has undergone wet conservation, open the system, release the alkaline solution and rinse with clean water;

If the boiler is stopped for a long time (more than one month), preservation must be done using a dry method, for this it is necessary:

Stop the boiler according to the instructions;

When the pressure in the boiler is equal to half the working pressure, purge the boiler according to the instructions;

After the temperature drops to 50-60ºС, drain the water from the boiler;

Clean the heating surface from scale and sludge;

Dry the inside of the boiler by blowing with compressed air;

Place previously prepared baking trays filled with quicklime into the collector (1 kg in each collector, or anhydrous calcium chloride, 0.5 kg each in each collector).

Before putting a dry-preserved boiler into operation, it is necessary to remove the trays with lime (calcium chloride) from the collectors.

Preservation and re-preservation of devices, protection, control and auxiliary equipment in accordance with the installation and operation instructions of the manufacturers of these devices and equipment.

Power supply to a boiler undergoing conservation must be excluded.

12. GENERAL INSTRUCTIONS

12.1. Major and current repairs of hot water boilers must be carried out in accordance with specially developed schedules. Minor defects discovered during operation must be eliminated as soon as possible with the boiler running (if operating rules allow) or whenhis stop.

12.2. Safety measures during operation, preparation for work, operating procedure, measurement of parameters, adjustment and tuning, checking the technical condition during operation, characteristic malfunctions and methods for eliminating them, and maintenance must be carried out in accordance with the relevant sections of the technical description of the boiler.

REGULATORY DOCUMENTS FOR THERMAL POWER PLANTS AND BOILER HOUSES

METHODOLOGICAL INSTRUCTIONS FOR
PRESERVATION OF THERMAL MECHANICAL
EQUIPMENT WITH APPLICATION
FILM FORMING AMINES

RD 34.20.596-97

INDUSTRY GUIDANCE DOCUMENT

This Industry Guidance Document:

Developed in accordance with the requirements of the Rules for the technical operation of power plants and networks of the Russian Federation (RD 34.20.501-95);

Applies to the main thermomechanical equipment of thermal power plants and establishes the method of conservation and the sequence of operations for its implementation during various types of shutdowns (planned and emergency shutdowns, shutdowns for current, medium and major repairs, shutdowns in reserve for a definite and indefinite period);

Intended for operating personnel of thermal power plants, hot water boiler houses, personnel of commissioning plants, power equipment manufacturing plants, design and research organizations.

1. GENERAL PROVISIONS

1.1. Preservation of thermal power equipment (boilers, turbines, heaters) using amine-containing compounds is carried out to protect steam-water paths from atmospheric corrosion in the following cases:

Short-term planned or emergency shutdowns;

Shutdowns for routine, medium or major repairs:

Putting equipment into reserve;

When taking equipment out of service for a long period of time.

1.2. The protective effect is ensured by creating a molecular adsorption film of a preservative on the internal surfaces of the equipment, which protects the metal from the effects of oxygen, carbon dioxide, and other corrosive impurities and significantly reduces the rate of corrosion processes.

1.3. The selection of conservation process parameters (time characteristics, preservative concentrations, etc.) is carried out on the basis of a preliminary analysis of the state of the power unit equipment (specific surface contamination, sediment composition, water chemical regime, etc.).

1.4. During conservation, concomitant partial washing of the steam-water paths of the equipment is carried out from iron- and copper-containing deposits and corrosive impurities.

1.5. The quality of preservation is assessed by the specific sorption of the preservative on the surface of the equipment, which should not be lower than 0.3 μg/cm 2 . If possible, gravimetric studies of witness samples are carried out and electrochemical tests of cut samples are performed.

1.6. The advantages of this conservation technology are as follows:

Reliable protection of equipment and pipelines is ensured, including in hard-to-reach places and stagnant zones, from standing corrosion for a long period of time (for a period of at least 1 year);

Equipment startup time is significantly reduced. exploitation;

It is possible to protect against corrosion not only specific equipment individually, but also the entire set of this equipment, i.e. the energy block as a whole;

The corrosion-protective effect remains after drainage and opening of the equipment, as well as under a layer of water;

No special measures for re-preservation are required, rapid re-commissioning of both individual elements and all mothballed equipment as a whole is ensured;

Allows you to carry out repair and maintenance work with opening of equipment;

Conservation is carried out without significant time labor costs, heat and water consumption;

Environmental safety is ensured;

The use of toxic preservatives is excluded.

1.7. Based on these guidelines, each power plant must draw up and approve work instructions for the conservation of equipment with a detailed indication of measures to ensure strict implementation of the conservation technology and the safety of the work being carried out.

2. INFORMATION ABOUT THE PRESERVATIVE

2.1. For preservation, the preservative flotamine (octadecylamine stearic technical), produced by the domestic industry, is used, which is one of the highest film-forming aliphatic amines. This is a white waxy substance, the main properties of which are given in TU-6-36-1044808-361-89 dated 04/20/90 (instead of GOST 23717-79). Along with the domestic preservative, a foreign analogue of ODACON (ODA condensation) with an increased degree of purification can be used, complying with the European standard DIN EN ISO 9001:1994 with the following main parameters:

2.2. Preservative sampling and acceptance rules must be carried out in accordance with GOST 6732 (organic dyes, intermediate products for dyes, textile auxiliary substances). The indicators of technical requirements provided for in the technical specifications correspond to the world level and consumer requirements.

2.3. The maximum permissible concentration of flotamine in the air of the working area should not exceed 1 mg/m 3 (GOST 12.1.005-88).

RD 34.20.593-89

METHODOLOGICAL INSTRUCTIONS
ON THE USE OF CALCIUM HYDROXIDE FOR PRESERVATION
THERMAL POWER AND OTHER INDUSTRIAL EQUIPMENT
AT THE FACILITIES OF THE USSR MINISTRY OF ENERGY

Valid from 01/01/89
until 01.01.99*
__________________
* See the Notes label for expiration date. -
Database manufacturer's note.

WORKED BY the All-Union Interindustry Research Institute for the Protection of Metals from Corrosion, REU "Mosenergo", 1st Moscow Order of Lenin and Order of the Red Banner of Labor Medical Institute named after. I.M.Sechenova

PERFORMERS A.P.AKOLZIN (All-Union Interindustry Research Institute for the Protection of Metals from Corrosion), G.A.SHCHAVELEVA (REU "Mosenergo"), Y.Y.KHARITONOV (1st MMI)

APPROVED by the Main Scientific and Technical Directorate of Energy and Electrification on December 30, 1988.

Deputy Head A.P. BERSENEV


These Guidelines outline a method for protecting thermal power equipment from standstill corrosion when putting it into reserve, as well as during emergency and planned shutdowns.

Preservation with a calcium hydroxide solution is used for any hot water boilers and for steam drum boilers with a pressure of up to 4.0 MPa that do not have superheaters, as well as for steam boilers with superheaters, but the superheaters themselves are not preserved.

The guidelines apply to stationary power plants, heating boiler houses, enterprises with hot water and steam power boilers with a pressure of up to 4.0 MPa, and must be taken into account by design organizations.

Based on these Guidelines, enterprises draw up local working instructions for conservation.

When preserving equipment, it is necessary to comply with the current “Safety Rules for the Operation of Thermal Mechanical Equipment of Power Plants and Heating Networks” (Moscow: Energoizdat, 1985), as well as the precautionary measures set out in Section 4.

1. CHARACTERISTICS OF THE METHOD FOR PRESERVATION OF THERMAL POWER EQUIPMENT WITH CALCIUM HYDROXIDE

1. CHARACTERISTICS OF THE PRESERVATION METHOD
THERMAL POWER EQUIPMENT WITH CALCIUM HYDROXIDE

1.1. The method of protection against parking corrosion (preservation) of thermal power equipment, based on the use of inhibitory solutions of calcium hydroxide, is highly effective.

1.2. Calcium hydroxide (see background appendix) is a non-funded local product, making it widely available. It is also a waste product from a number of industries (for example, welding). Calcium hydroxide solutions are harmless to humans and the environment. When discharging waste solutions, it is necessary to dilute them with water to pH<8,5. Вследствие малой растворимости (около 1,4 г/л при 25 °С) создать концентрации раствора гидроксида кальция, опасные для жизни и здоровья человека, практически невозможно. Кроме того, в естественных условиях (водоемах, почвах) происходит быстрая нейтрализация гидроксида кальция путем его взаимодействия с углекислым газом атмосферы, в результате чего образуется карбонат кальция (мел), также безопасный для здоровья человека.

1.3. The effectiveness of the protective action of calcium hydroxide solutions against the metal of thermal power equipment is, in all respects, significantly higher than that of a number of other inhibitors.

For example, the corrosion rate of steel in the presence of calcium hydroxide (protective concentration, see clause 1.4) in environments containing up to 3 g/l chlorides is 1.5-2.2 times lower than in sodium silicate solutions, and 10 -12 times lower than in sodium hydroxide solutions at the same equivalent concentrations of inhibitors. The corrosion rate was determined gravimetrically and by the polarization resistance method.

1.4. The protective concentration of calcium hydroxide solutions for equipment made of carbon steel is 0.7 g/l or higher.

Overdose is not possible due to its limited solubility.

1.5. During long-term preservation (more than a month) in conditions of contact of the preservative solution with air, its concentration gradually decreases due to the absorption of acidic components of the air. A decrease in pH to a value less than 8.3 is unacceptable, since it indicates the appearance of carbonates, bicarbonates and hydrosulfites in the preservative solution, i.e. products of interaction of calcium hydroxide with air components. The result of this interaction is a decrease in the protective effect. The preservative solution is monitored by sampling at least once a week. If the pH of the solution decreases below the permissible level (disappearance of phenolphthalein color), the preservative solution should be renewed.

In the absence of contact with air, the protective properties of the solution are not limited by time.

1.6. The presence of corrosion activators (chlorides in concentrations up to 0.365 g/l and sulfates up to 0.440 g/l) in a solution of calcium hydroxide with a concentration of 0.7 g/l and higher practically does not reduce the protective properties of preservative solutions. This is explained by the fact that in solutions of calcium hydroxide, a phase protective film with a thickness of 12-21 microns is formed on the surface of carbon steel, consisting of insoluble hydroxo- and aqua-complexes of iron and calcium, which also includes other compounds and ions.

1.7. If bicarbonates are present in the aqueous preservative solution (when preparing the solution with river water), the protective properties of the films formed on the steel are increased due to the additional formation of layers of calcium carbonate (chalk).

1.8. The preservative solution is prepared in water with a temperature below 40 ° C, since with increasing temperature the solubility of calcium hydroxide in water decreases and the protective properties of the solution decrease.

2. CONSERVATION TECHNOLOGY

2.1. Preservative solutions of calcium hydroxide are prepared from milk of lime. At a water treatment facility with pre-treatment, you can use a lime solution prepared for clarifiers.

2.2. To prepare lime milk, almost any slaked lime can be used, including building lime, with preliminary removal of the remaining lime; fluff lime; calcium carbide slaking waste from acetylene production. Slaked lime and lime milk should not contain sand, clay and other contaminants that are insoluble in water (see paragraphs 2.5, 2.6, 2.8).

2.3. Preservative solutions are prepared using condensate or chemically purified water. Sea and boiler water is not suitable for preparing preservative solutions.

2.4. The preservation solution is prepared in a separate supply tank with a volume of 20-70 m3. It is more convenient when the volume of the supply tank exceeds the volume of the equipment being preserved. The amount of slaked lime supplied to the supply tank for preparing the preservative solution is 1-1.5 kg per 1 m of water in the tank. The lime is first mixed with water to a liquid consistency, then the mixture is poured into the tank through a mesh with cells no larger than 1 mm to retain solid impurities.

2.5. The preservative solution sits in the tank for 10-12 hours until the reagent is completely clarified and dissolved.

2.6. The preservative solution can be supplied by gravity from the supply tank to the boiler. To do this, the tank is installed above the boiler. If the supply tank is located at the bottom, the boiler is filled using pumps.

2.7. The selection of preservative solutions is carried out not from the bottom point of the supply tank, but from a level of 40-50 cm from the bottom of the tank in order to avoid the entry of solid insoluble particles into the boiler. For the same purpose, before being fed into the boiler, preservative solutions are passed through any mechanical filter.

2.8. The preservative solution is fed into a completely drained and cooled boiler. Preservation can be carried out either on a boiler that has been cleaned chemically or mechanically, or on a boiler that has internal deposits. The solution is supplied through the lower collectors of the boiler.

2.9. The preservative solution fills the entire internal volume of the hot water boiler. If the water heating boiler has a closed circulation circuit, then the entire circuit, including pipelines and heat exchangers, is filled with a preservative solution. In drum boilers, water economizers, guard and downcomer pipes and the boiler drum are filled.

2.10. If the amount of solution prepared in the supply tank is not enough to fill the entire boiler, the next portion of the preservative solution is prepared in the supply tank in accordance with paragraphs 2.4-2.8.

2.11. For hot water boilers, it is advisable to provide stationary systems for preparing preservative solutions and feeding them into the boiler. Possible schemes for preparing and supplying preservative solutions are presented in Fig. 1, 2. In Fig. 1, the scheme has a saturator tank for preparing solutions. There is also a filter (for example, a type of salt solvent for water treatment). Figure 2 shows another conservation option, which involves supplying a preservative solution using an acid washing scheme for hot water boilers.

Fig.1. Scheme for introducing calcium hydroxide into preserved equipment

Fig.1. Scheme for introducing calcium hydroxide into the equipment being preserved:

1 - filling funnel; 2 - lime milk preparation tank; 3 - preservative preparation tank
calcium hydroxide solution; 4 - filter; 5 - supply tank; 6 - ejector; 7 - feed pump; I - condensate;
II - chemically purified water; III - steam; IV - sampling before adding calcium hydroxide; V - sampling after
injection of calcium hydroxide; VI - from nutrient tanks; VII - for boilers

Fig.2. Preservation scheme for hot water boilers with Ca(OH)(2) solution using acid washing scheme

Fig.2. Scheme for preserving water heating boilers with a solution using an acid washing scheme: If the payment procedure on the payment system website was not completed, monetary
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