RU2101608C1 - Method of preservation of hollow metal members of heat power equipment and system for realization of this method - Google Patents

Abstract

FIELD: preservation of heat power equipment. SUBSTANCE: to protect equipment against corrosion during idle period, dehumidifier air fed to it at temperature corresponding to temperature of surrounding medium. Air is first compressed to pressure of 3 to 15 kgf/sq.cm, cooled down to required temperature at simultaneous dehumidification, throttled to pressure of 0.5 - 1.5 kgf/sq. cm and distributed among items of equipment to be preserved. EFFECT: enhanced efficiency. 3 cl, 2 dwg

Description

 The invention relates to the field of power engineering and can be used for preservation of steam turbines, boilers, steam pipelines, generators, heat exchange auxiliary equipment, pipelines of network and make-up water, and can be used when shutting down power equipment in reserve for various periods of time, for repair.

 With prolonged downtime of equipment at TPPs and gas stations, it becomes necessary to protect parts of power equipment from corrosion.

 A known method of preservation of the steam-water tract using an inert gas of nitrogen while maintaining excess pressure in the path during the entire time of conservation.

 The disadvantage of this method is the organic field of application. It is impossible, for example, to use the indicated method for preservation of a turbine due to large nitrogen leaks through leaks and end seals, which means that the power unit as a whole cannot be preserved by nitrogen. It is impossible to preserve nitrogen and one boiler, because in the block scheme there are no shutoff valves on the side of the superheater, which will lead to a large nitrogen leak. In addition, preservation with nitrogen cannot be combined with the simultaneous repair of conserved surfaces.

A known method of preserving a drum boiler with an economizer by maintaining the circulation of boiler water with a temperature of at least 250 ^o C while simultaneously supplying ammonia solution to the boiler circuit through its drum, which is introduced into the drum immediately after the boiler stops, at the same time, aqueous ammonia is fed into the water economizer and periodically purging the boiler.

 The disadvantages of this method are the high cost of the reagents, the complex technology of their storage, preparation and disposal, environmental problems.

 A known method of preserving boilers and turbines by creating on the inner surface of the equipment an inhibitor layer deposited on the metal when the equipment is purged with hot air or dosing ODACON'B steam.

 The disadvantage of this method is the high cost of chemicals, the risk of an inhibitor entering the atmosphere, the formation of non-ventilated surfaces during conservation and the uneven distribution of the inhibitor over the metal, which leads to increased local corrosion, a limited scope due to the harmful oxidizing effect of the inhibitor on copper and its alloys.

 A known method of preservation of the internal cavities of the steam generator of thermal power plants, in which a vacuum is created in the steam generator and when the incoming air expands, it is "dried".

 The disadvantage of this method is the inability to repair equipment during conservation, in addition, at a low temperature inside the steam generator, condensation of water vapor begins from the outside of the condensed object, dew drops and corrosion of the external surfaces occurs.

 The closest technical solution is the method of preservation of turbine equipment, which includes the constant injection of dry atmospheric air into the cavity of the equipment to be preserved, the supply of which is carried out in the canned object in one direction with constant ventilation of the canned object. Before being transferred to the object, the air is heated in a special air heater, which provides air drying to the required value.

 The specified method of preservation of turbine units with heated hot air has the following disadvantages.

 For individual conserved surfaces, the method is ineffective due to air cooling in poorly ventilated volumes to ambient temperature, resulting in increased humidity and increased local corrosion.

 In addition, heated air has the ability to absorb moisture. And if the air on the way through the turbine or boiler is additionally moistened with water from the dead ends, then with subsequent cooling its humidity increases sharply. Thus, there is always the danger of moisture moving from the warm part of the equipment to the cold. It is almost impossible to obtain a uniform field of dry air in this case.

It requires high energy costs to maintain conserved equipment in a warmed up to about 60 ^o C; in addition, significant annual energy consumption for the conservation of one unit
This method requires the installation of additional equipment: ventilation and air heater; complex layout of the heater coil, etc. In some cases, the installation of electrostatic precipitators is required to heat the air.

 The conservation method can only be used for turbines, it is not suitable for the conservation of the entire power unit, including the boiler, pipelines and various auxiliary equipment due to the practical impossibility of preventing air cooling and moisture condensation in the branched pipe system of the boiler. Using this method on a turbine also does not provide reliable preservation of all elements and components of the turbine. Some components of the turbine will cool below the initial temperature of the heated air, its humidity in these places will increase and conditions will be created for local corrosion.

 A known scheme for preservation of turbine equipment, comprising an air supply pipe with an air blower installed on it, a heater, a conserved object with an air discharge line with shut-off valves.

 The disadvantages of this scheme are as follows.

 A large amount of air is required to be emitted from the conserved object to ensure constant ventilation in the object, which requires the installation of a fan over high-capacity air.

Large energy costs associated with maintaining the air temperature in the volume of about 60 ^o C at high costs.

 In non-ventilated spaces, air is cooled to ambient temperature with an increase in its humidity to the initial (possibly higher), which causes local corrosion.

 Limited scope (turbine only).

 It is impossible to repair heat power equipment at the same time as conservation.

 The scheme does not provide for regulation and distribution of air, as equipped with shutoff valves.

 The technical problem solved by the proposed technical solution is to increase the reliability of conserved equipment by significantly reducing parking corrosion by increasing the efficiency of conservation.

To solve this problem by a known method of preservation of hollow metal elements of heat power equipment, which is carried out by supplying a dry object to a conserved object; dry air is supplied at a temperature corresponding to (equal to) the temperature of the surrounding air object, for this the air is compressed to 3-15 kgf / cm ² before being fed to the conserved object, and then it is cooled to the temperature of the air surrounding the object, the formed moisture is removed and throttled to pressure 0.5-1.5 kgf / cm ² , regulate the air flow in the facility and its distribution throughout the facility, as well as the flow of water to the air cooler, while conservation begins after the moisture has been removed from the facility.

 To solve the problem in the well-known scheme for the conservation of hollow metal elements of heat power equipment containing an air supply pipe with an air blower, a conserved object and an air discharge line with locking elements; on the air supply pipe in front of the conserved object, a surface cooler, a separator with a water separating device and a throttle valve that controls the pressure in the object are additionally installed in series, and air outlets with throttle valves from each separate part of its internal volume are installed on the conserved object.

 The proposed conservation method is implemented using the circuit shown in FIG. one.

 The proposed scheme for the conservation of hollow metal elements of heat power equipment includes an air supply pipe 1, on which are located a sequentially installed air blower 2, a surface cooler 3, a separator 4 with a moisture separating device, a throttle valve 5 installed in front of the conserved object 6, for regulating the pressure in the latter. At the same time, on the conserved object 6, air exhaust lines 7 with throttle valves are installed, which provide control of the flow and distribution of air to the conserved object.

As an air blower 2 can be used compressors, exhauster, blowers, providing a pressure of at least 3-15 kgf / cm ² .

Air intake is produced inside or outside the room where the canned equipment is located. Air using a blower 2 compresses up to 3-15 kgf / cm ² (depending on the type of blower), while its temperature rises. Compressed air enters the cooler 3, where its temperature drops to the temperature of the surrounding air equipment and moisture condenses from the cooled air, followed by its removal in the separator 4. After removing moisture, the dry air is throttled with a pressure reducer to a pressure of 0.5-1.5 kgf / cm ² . In the process of throttling, the air is additionally dried. Before supplying air to a conserved object, moisture is removed from the latter. The distribution of air over the object and its flow rate are carried out using throttle valves 7, which cut into various places of the conserved object.

 The supply of dry air at a temperature corresponding to the temperature of the surrounding air equipment, avoids the loss of moisture (dew) on the outer and inner surfaces of the object.

 The air drying process is illustrated by the diagram shown in FIG. 2.

When the air is compressed, its initial state is characterized by point 1 (atmospheric pressure, temperature 3 ^o C, humidity conditionally maximum φ 100% d 20 g / kg rv). Using a supercharger, air is compressed to a pressure of P _n , point 2 (P _n 5 kgf / cm ² ). With subsequent cooling of the air, the relative humidity initially rises to 100% (in the 2-A process). Next, the process of extracting water from the air begins (process A-3). If under the operating conditions of the CHP it is possible to cool the air to t ₃ below the initial temperature t ₁ point 3 (t ₃ 25 ^o C), the moisture content of the air will be up to d ₂ (d ₂ 4 g / cm rv).

выше первоначальной t₁ (t₃ 35^oC) точка 3', влагосодержание воздуха станет

7,2 г/кг с.в.).If, under the conditions of operation of the CHPP, it is possible to cool the air only

above the initial t ₁ (t ₃ 35 ^o C) point 3 ', the moisture content of air will become

7.2 g / kg d.v.).

After separation, the air is throttled to the required pressure P _about (P _about 1.2 kgf / cm ² ) point -4 and 4 '. On the id "diagram, points 3 and 4 coincide, because the moisture content and air temperature do not change during the throttling process. At points 3 and 3 ', the air humidity is 100% at points 4 and 4' φ _p - 24%
Thus, thermodynamic drying of air provides with a considerable margin the necessary air humidity, which practically prevents parking corrosion (relative humidity below 50%). The indicated moisture value is corrosion-safe.

Claims (2)

1. A method of preserving hollow metal elements of heat power equipment by supplying dry air to a conserved object, characterized in that dry air is supplied at a temperature corresponding to the temperature of the air surrounding the object, for this purpose, before being fed into the conserved object, the air is subsequently compressed to 3 15 kgf / cm ² when it is subsequently cooled to the temperature of the air surrounding the object, the formed moisture is removed and throttled to a pressure of 0.5 1.5 kg / cm ² , the flow rate and distribution are regulated spirit in the object, the flow of water to the air cooler, while conservation begins after removal of moisture from the object.  2. Scheme for implementing the method of preservation of hollow metal elements of thermal power equipment, comprising an air supply pipe with an air blower installed on it, a conserved object and an air discharge line with shut-off bodies, characterized in that the surface-mounted air cooler is additionally equipped with a series-connected surface air cooler in front of the conserved object , a separator with a dehumidifier and regulating the pressure in the facility, a butterfly valve, and on On a serviced object, air outlets with throttle valves from each separate part of its internal volume are installed.

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