Boiler rooms: System of planned preventive maintenance of equipment. Repair of boiler equipment

Stopping equipment for repair is carried out strictly according to plan. This system is called planning preventive maintenance(PPR). The purpose of the PPR is to restore the boiler equipment to its working condition, reduce the time and improve the quality of repairs, as well as lengthen the life of the equipment between repairs.

The basis for determining the planned timing and volume repair work a detailed technical nomenclature of work for all types of repairs for each type of equipment should serve.

The good quality of the repair is ensured by its timely and thorough preparation, with the preparation defective statement and a repair schedule indicating the full scope of work, the arrangement of workers by type of work, the preparation of spare parts, materials and equipment, measuring instruments, tools, fixtures and rigging devices.

Based on the PPR, the type and frequency of repairs are established.

Maintenance- carried out in order to ensure the normal operation of the boiler house at rated power. It consists of partial disassembly, inspection and determination of the condition of equipment and individual components, drawing up a preliminary list of defects, repair or replacement of worn parts and components, inspection and testing of repaired parts.

Refurbishment- carried out during the elimination of damage to boilers caused by an explosion, fire or their prolonged inactivity.

Overhaul– is carried out to bring the technical indicators of the boiler and auxiliary equipment to design and calculated values, simultaneously with work on improving equipment. The scope of the overhaul includes a complete inspection with a check of the condition and determination of the degree of wear of equipment, fittings, etc. At the same time, replacement and restoration of worn components and parts, external and internal cleaning are carried out. The overhaul also includes the replacement and reconstruction of heating surfaces, the transfer of boilers to work on other types of fuel, the inspection and elimination of defects in welded joints.

Repair Frequency- set depending on the allowable wear separate parts and duration of uninterrupted operation.

The need for unscheduled emergency repairs occurs as a result of accidents accompanied by damage to individual components, as well as due to improper operation, equipment overload, etc. Depending on the volume, emergency repairs can be classified as current or capital. In the event of an emergency failure of the boiler equipment, an act is drawn up in which the causes of the accident and the scope of work are indicated.

In addition to these types of repairs during the operation of boiler equipment, overhaul maintenance, which includes maintenance of equipment (lubrication, wiping, cleaning, regular external inspection, etc.) and minor repairs of equipment (correction of minor defects). Overhaul maintenance is not planned and is performed during the operation of the boiler equipment.

⇒ See also: ⇓

1. List of equipment maintenance and repair services - daily maintenance, operation and current repair of thermal mechanical equipment and boiler room safety automation. Modes of operation of boiler houses during the inter-heating period ....
2. Service maintenance boiler rooms and current repairs of all equipment within the boiler room (electrical, heat engineering, chemical water treatment systems, instrumentation, automation and alarm systems of the boiler room), ensuring the operation of the boiler room. Technical Acts are being drawn up....
3. Maintenance and operation of boiler houses - the list and volumes of rendered services: - Operation of the main and auxiliary boiler equipment; - Maintenance and repair of main and auxiliary boiler equipment....
4. Preparing the boiler room and heating system for the next heating period- how to do it? Measures to prepare boiler rooms for operation are carried out after completion heating season. During the inter-heating period, necessary repairs and...

Technical examination of the boiler is carried out in order to establish the boiler's serviceability and suitability for further work. It consists of external, internal inspections and hydraulic testing.

Each boiler must be subjected to a technical examination before being put into operation, periodically during operation and in necessary cases- extraordinary inspection. Technical certification is carried out by a specialized organization.

Inspections of the boiler are carried out in order to check the correct installation and equipment of the boiler in accordance with the registration documents and for the absence of damage (initial survey) or its suitability for further operation (periodic or extraordinary surveys). During inspections, attention is drawn to the presence of cracks, tears, bulges, bulges, corrosion damage, traces of steaming and gaps in welded and rolling joints, as well as damage to the lining, which can cause a danger of overheating of the metal of the boiler elements.

Daily inspection is carried out at the reception of the shift for approximately 20-30 minutes;

Monthly inspection is carried out within 2-3 days;

Semi-annual inspections are carried out within 7-8 days;

The current repair of boilers of the DKVR, DE, PTVM, MZK, etc. types is carried out once a year;

Overhaul of the same boilers is carried out once every 3.5 - 4 years.

In more detail, the terms for the overhaul of boilers, depending on the method of fuel combustion, the power of the boiler, as well as the terms for the overhaul of assembly units of boilers are given in GOST 24005-80 "Stationary steam boilers with natural circulation. General technical requirements".

For other equipment, repairs are carried out at different times. For example, for pumps, maintenance is recommended to be carried out once every 6 months, and overhaul once every 6 years.

Preparation of equipment for repair.

Preparation of equipment for repair is carried out in accordance with the requirements of RD-69-94 "Typical specifications for the repair of steam and hot water boilers for industrial energy".

The scope of repair work is determined by the owner of the boiler based on the results technical certification and diagnosis. Before the start of work repair organization develops technological documentation for repairs, including preparation of a repair site for welding or surfacing. Responsibility for the completeness and quality of the work performed lies with the organization or person who carried out the repair.

Repair of the boiler is carried out by a specialized organization licensed by Gosgortekhnadzor to carry out this type of work. Certified welders, certified non-destructive testing specialists and locksmiths with a rank of at least 4, who have practical skills in boiler repair, are allowed to perform work.

Prior to the start of repairs, the following documentation is drawn up for each boiler:

Who technical condition boiler before repair;

Work organization project and technological instructions for welding;

Specification for equipment, spare parts, tools, equipment, rigging devices.

Detailed description repair work should be recorded in the repair log. In particular, the journal records information about the amount of work performed on cleaning and replacing boiler elements, as well as information about the methods and sizes of samples of unacceptable defects (corrosion damage, cracks, etc.), materials and electrodes used, welding technology and information about welders, about the methods and results of control.

The organization that performed the repair draws up and submits to the customer in a bound form the following technical documentation:

Repair forms;

Certificates for welding of control welded joints or for cutting production welded joints;

Protocols of mechanical tests and metallographic studies of samples from control welded joints;

Certificates for welding consumables, pipes, sheet, fittings, flanges, fittings, fittings, fasteners;

Protocol for running a ball through pipes;

Copies of welder's certificates.

When repairing boiler drums using welding, the following technical documentation is additionally drawn up:

Boiler inspection reports before and after repair;

Repair log of the drum (it provides a development of the drum, on which the location and numbers of pipe holes and fittings are applied; the location and numbers of the drum seams, defects and samples found, etc. In addition, a table on welding is given)

Repair log of pipe holes and fittings;

Technology for the repair;

Act for the replacement of fittings;

Conclusions on the results of ultrasonic, magnetic particle testing and transillumination for the absence of defects after repair;

Conclusions on the results of the control of the deposited areas, performed by the ultrasonic method after a hydraulic test;

The act of checking the technological properties of the electrodes.

The admission of people to carry out repairs inside the boiler should be made only with written permission, called an order - admission.

Basic technological processes of repair of boilers.

Repair of boilers is preceded by cleaning them from external and internal pollution.

External cleaning boilers from pollution consists in removing accumulated deposits of ash, soot, slag, residues of unburned fuel, as well as rust and scale from the heating surfaces, furnace walls and gas ducts. For cleaning, cutters, steel brooms, brushes, banniki, scrapers and other tools are used, as well as blowing compressed air. In some cases, washing of pipes with a jet of water is used, followed by obligatory drying.

Internal cleaning boiler is directed to removal from internal surfaces drums, pipes, collectors, pipes of deposits of a scum, slime and salts. Initially, part of the deposits is removed by a jet hot water, which partially dissolves and washes them. The remaining deposits are removed mechanically or chemically.

Mechanical cleaning is carried out with the help of special tools, such as metal brushes, ruffs, banniks, cone heads (cone cutters), etc.

Rollers are widely used for cleaning boiler pipes, which are driven by an electric motor with flexible hose. The cone has the shape of a gear, which removes scale with its teeth. Typically, five to fifteen cutters (gears) are used, arranged symmetrically in a circle in the head of the cleaning device and connected to the axis of the head.

When the axis rotates, the cutters under the action of centrifugal forces are pressed against the surface of the scale and clean it off. After applying the cutters, each pipe is cleaned with a wad of tow or rags and blown with compressed air. To make sure that the pipe is passable, a calibrated steel ball on a cable is passed through it.

To facilitate mechanical cleaning, before its implementation, partial dissolution is carried out, and mainly scale softening by alkalizing the boiler. When alkalizing, they introduce into the boiler water sodium hydroxide NaOH, soda ash Na 2 CO 3 or trisodium phosphate Na 3 PO 4. Depending on the composition of the scale and its thickness, the reagents are introduced, approximately, in the following quantity: soda - 10-20 kg, sodium hydroxide and trisodium phosphate - 3-6 kg per 1 m 3 of the water volume of the boiler.

During alkalization, the water in the boiler is heated by steam from other boilers or by weak fire heating without increasing pressure or with increasing steam pressure. The duration of alkalization is 30-60 hours. After alkalization, the solution is drained from the boiler, and the boiler is thoroughly washed hot water. After that, immediately proceed to mechanical cleaning. Alkalinization is usually carried out in strict accordance with the instructions for alkalizing the boiler, which is developed by the boiler manufacturer. Alkalinization is also used to clean the boiler from rust and oils after its installation.

Acidic flushing of boilers allows you to completely dissolve the scale and remove it from the boiler. The acid solution is able to penetrate those contaminated heating surfaces that are usually inaccessible to mechanical cleaning.

Most often, hydrochloric acid is used to dissolve scale, the salts of which have a high solubility in water. Flushing is carried out with a 4-7% acid solution heated to 50-65 0 C. The boiler is completely filled with the solution. With the help of a washing tank and a pump, the circulation of the solution through the boiler is organized for 6-18 hours. To prevent corrosion of the metal, corrosion inhibitors are introduced into the acid solution, for example, grades PB - 5, urotropine, etc. After washing is completed, the boiler is alkalized to neutralize acid residues.

Instead of hydrochloric acid, chemical cleaning of the boiler can be carried out with less aggressive organic acids and complexing agents.

Of the organic acids (citric, formic, adipic), the most widely used lemon acid. The concentration of acid in the solution should be within 1-3% (pH not more than 4.5), the circulation rate of the solution in the boiler should be from 0.5 to 1.8 m/s, and the temperature of the solution should be 95-105 0 C. Duration of dry cleaning is 3-4 hours. The spent solution is forced out of the boiler with hot water.

Of the complexones, Trilon-B is the most widely used, which is the sodium salt of ethylenediaminetetraacetic acid (EDTA). At a solution concentration of 0.5-1% and a circulation speed of 0.5-1 m / s, the duration of cleaning is 4-8 hours. The temperature of the solution is 100 0 C.

The possibility of using reagents for dry cleaning is established by the boiler manufacturer.

Repair of heating surfaces of boilers.

Minor corrosion and mechanical damage to drums, manifolds, boiler bodies, flame tubes and fittings are eliminated by surfacing or welding, and significant defective areas are cut out and replaced with new ones.

Pits in drums up to 2-3 mm deep after cutting are filled with cement mortar with crushed glass. Damages longer than 3 cm and with a depth of more than 2-3 mm are filled with metal using electric arc welding. However, surfacing is possible only if, after cutting the damage, the wall thickness at the sampling site is more than 3 mm.

Cracks up to 1/3 of the drum wall thickness are repaired as surface cracks, and deeper cracks are repaired as through cracks. The boundaries of cracks are determined by magnetic or color flaw detection and fixed by punching. To prevent the development of cracks in length at a distance of 10-30 mm from the intended boundaries, drillings with a diameter of at least 4-5 mm are made.

Cracks with a depth of more than 1/3 of the wall thickness are cut through. The edges of the crack are cut with a chisel in the form of a cup-shaped groove, after which the holes and grooves are melted by electric welding. Surfacing should extend beyond the groove area by 5-8 mm on each side with a reinforcement (increase in thickness) of at least 2 mm. The reinforcement is removed by grinding flush with the base metal.

Deeper corrosion on a large surface is eliminated by cutting out defective areas and welding patches, replacing shells, fittings or other elements. The patch holes must be larger than the zone damaged area 20-50 mm in both directions and be carried out by gas or flame welding. The shape of the cutout for the patch must be oval or rectangular with a smooth rounding of the corners with a radius of at least 100mm. The desired curvature of the patch is given by rolling.

Defective sections of pipes or the pipes themselves are removed by gas, flame and mechanical cutting. Rolled pipes may be removed from the drum by knocking out, while saving the sockets from damage.

Warped screen and boiler pipes are subjected to bending or straightening if their curvature or displacement is beyond the tolerance limits

Leaks in welded pipe joints are eliminated by cutting defective sections to healthy metal, followed by welding. Sample form in cross section should have a cup-shaped shape with a bevel angle of 12-15 0, and the width of the groove should be 1-1.5 mm more than the width of the seam. Before repairing joints with cracks, drillings with a diameter of 2-3 mm are performed at the ends of the crack, and the defective metal is removed.

Defective flaring joints are eliminated by replacing the defective end of the pipe with a new one or the entire pipe, followed by flaring. Pipe ends prepared for rolling should be cleaned to a metallic sheen to a length of 50-80 mm.

During emergency repairs, defective pipes are removed, and instead of them, plugs are installed at the attachment points. When the economizer cast-iron pipes break, they are replaced with new ones or switched off by rearranging the rolls. Can be installed inside cast iron pipe steel pipe with disassembly of its ends and clamping them with rolls.

Section content

Equipment during operation is subject to wear and tear and loses its original performance. By following the rules of operation, you can reduce the wear of parts. By holding quality repair restore the equipment to work. Maintenance technological equipment is assigned to the operating personnel, who are obliged to withstand the operating modes, lubricate the mechanisms and take other measures to ensure its uninterrupted operation.

The elimination of minor equipment defects (wear of gland packings, gaskets, replacement of bolts, etc.) is carried out at the end of the production operation, when the equipment is not in operation. At the same time, inspections of assemblies and parts are carried out to identify their consistency and develop measures for the upcoming repair of equipment. In case of continuity of production processes, stopping the equipment for inspection and current repair produce in without fail at least once a month.

More complex repairs with the replacement of worn parts are carried out according to the schedule established and agreed upon at the enterprise. Random, emergency and unforeseen repairs disrupt the operation of equipment and disrupt the planned production. Therefore, measures to prevent equipment downtime caused by breakdowns and malfunctions of individual components and parts should occupy a central place in the work of operating personnel.

For everyone industrial enterprises there is a system of preventive maintenance of equipment, which is a set of organizational and technical measures carried out in a planned manner for the care, supervision, maintenance and repair of equipment.

The system of scheduled preventive maintenance (PPR) aims to ensure the prevention of premature wear of equipment parts and possible breakdowns or accidents by performing preventive work on schedule. Timely execution of repairs should ensure high reliability and equipment performance throughout the entire operational period. The PPR system provides for repairs regardless of the condition and degree of wear of the equipment, which eliminates accidental repairs and forced downtime, increases production discipline in compliance with the rules for operating process equipment.

For the successful implementation of the system PPR equipment a number of preparatory work, including:

Full accounting of machines, devices and communications to be covered by the PPR system;

Preparation of technical passports for equipment and their systematic maintenance;

Preparation of anti-corrosion maps for equipment and pipelines operating in an aggressive environment;

Development specifications for the repair of equipment;

Drawing up specifications, albums, drawings and specifications for the manufacture of spare parts, replaceable units and assemblies, indicating normative term service and stock standards;

Development of consumption rates auxiliary materials, rolled products, pipes, sheet metal and purchased products necessary for the repair of equipment;

Development of annual and monthly PPR plans, as well as a system for organizing and monitoring their implementation;

Development of instructions for carrying out repair work related to conducting hot and gas hazardous work inside vessels and apparatuses in which explosive and toxic substances are processed;

Development of organizational and technical measures aimed at the successful implementation of all types of repairs, cost reduction and reduction of repair time.