RU170935U1 - THREE-STEP SPEED JET EJECTOR - Google Patents

Abstract

The utility model relates to the field of power engineering and can be used to increase the efficiency of the operation of condensing units as part of steam turbines and increase the reliability of the equipment of condensing units. The useful model is a three-stage steam jet ejector, including nozzles located in each stage sequentially along the movement of the working steam receiving chambers, mixing chambers, diffusers, adapter pipes and coolers. The nozzles are axially movable relative to the diffuser. Reducers are located below the diffusers. Ejector coolers are made vertical and remote using U-shaped tubes. The coolers are arranged triangularly relative to each other, made with the same body diameters. The claimed technical solution is aimed at increasing the efficiency and reliability of the ejectors of condensing units of steam turbines by creating the possibility of changing the distance between the nozzle and the diffuser for various initial operating parameters, reducing corrosion and erosion wear of the adapter pipes the ejector associated with the presence of a stagnant condensate zone, eliminating the flow of vapor-air mixture into zones with higher pressure due to leaks in the structure, increased durability of the cooler tubes.

Description

The utility model relates to the field of power engineering and can be used to improve the performance of condensing units in steam turbines and increase their reliability.

Steam-jet three-stage ejectors of various manufacturers are known (Leningrad Metal Plant, Ural Turbine Plant, Kharkov Turbine Generator Plant, Kaluga Turbine Plant), such as EP-3-700, EP-3-3, EP-3-25 / 75 and others, consisting of three stages, each of which contains a nozzle, a receiving chamber, a diffuser and a cooler (RD 34.30.302-87 Guidelines for setting up and operating steam-jet ejectors of condensing units of turbines of thermal power plants and AS / Belevich AI // M .: Ministry of Energy of the USSR , 1990.34 s.). Most of the well-known steam jet three-stage ejectors are made with coolers "with built-in tube bundle." One of the main disadvantages of this design is the overflow of the vapor-air mixture from areas with high pressure to areas with less pressure, which reduces the efficiency of the ejector.

Closest to the technical nature of the claimed utility model is the well-known steam-jet ejector EPO-3-135, developed by the Ural Turbine Works, made with coolers of the type "with remote tube bundle". (Barinberg G.D. Steam Turbines and Turbine Units of the Ural Turbine Plant / G.D. Sakhnin Yu.A. Yekaterinburg: Aprio, 2007. 460 p.). In the EPO-3-135 ejector, portable coolers are used, which eliminates the flow of the vapor-air mixture into areas with lower pressure. Coolers of this ejector are made inclined at an angle of 15 ° to the horizontal. Between the diffusers and coolers are made adapter pipes through which the vapor-air mixture moves.

The disadvantage of this solution is that, due to the inclined design of the coolers, the transition pipes have zones where condensate stagnates, which is why there is a high risk of increased corrosion and erosion wear. This defect can lead to the appearance of places of air suction in the ejector. In addition, the disadvantage of the EPO-3-135 ejector is that straight tubes are used in ejector coolers that accumulate thermal stresses when operating in high temperature environments (2 and 3 stages). The EPO-3-135 ejector cannot be reconfigured if external factors that determine the functioning of the air removal system and the condensation unit as a whole change, such as, for example, the temperature of the cooling water at the inlet to the condenser.

The objective of the claimed technical solution is to protect the transition nozzles of the ejector from corrosion-erosion wear associated with the presence of a stagnant condensate zone, to increase the durability of the cooler tubes associated with the accumulation of thermal stresses, to exclude the flow of the vapor-air mixture into areas with lower pressure associated with non-tight design and to improve reliability of work by changing the axial distance between the nozzle and the diffuser.

This problem is solved by the fact that the nozzles are made with the possibility of axial movement, the transition pipes are rotary, and the coolers are remote, vertical, with U-shaped tubes. Ejector coolers are located relative to each other in the form of a triangle and are made with the same diameters.

The utility model is illustrated by the drawing (Fig. 1), which shows the ejector design, where 1 is the nozzle, 2 is the receiving chamber, 3 is the diffuser, 4 is the adapter pipe, 5 is the cooler, 6 is the U-shaped tube.

The device operates as follows. Working steam with an absolute pressure of 0.5 MPa enters the steam jet devices of the steps through the steam line. Passing through the nozzle, the flow of working steam increases its speed, while the pressure in the steam flow is significantly reduced. Behind the nozzle of the first stage, the flow of working steam enters the mixing chamber of the first stage, captures the vapor-air mixture (PVA) coming from the condenser of the steam turbine and carries it along with it into the diffuser, where both flows are mixed, and the speed of the mixed stream decreases significantly, and the pressure increases . Behind the diffuser of the first stage is a vapor-air mixture cooler. The stage cooler is a shell-and-tube heat exchanger, in which steam from PVA is condensed on the cooling tubes. Air and residues of non-condensing vapor are sucked into the mixing chamber of the second stage. In the second stage, a similar process occurs, then the flow is sucked into the mixing chamber of the third stage. After the flow of the PVA through the tube bundle of the cooler of the third stage, the air and the rest of the non-condensed vapor are removed into the environment.

The ejector consists of steam-jet devices of the first, second and third stages located vertically (working steam and the sucked in air-vapor mixture move from top to bottom) next to the cooler bodies of each stage, respectively. The working steam is supplied to the steam jet apparatus from above through the steam line. Coolers of the first, second and third stages are also located vertically. Stage coolers are mounted on a block of water chambers, which, in turn, is mounted on a support frame. Condensed working steam is discharged from the cooler tube plate through the nozzle. A flange connection is made between the cooler body and the water chamber, in which the cooler tube board is clamped.

The proposed design allows to achieve the following results:

1. The coolers of the ejector stages are made remote and vertical, in separate buildings. Steam-jet devices are installed next to the housings and are connected to them by adapter pipes. This eliminates the possibility of corrosion-erosion wear. Also, this design ensures the tightness of each stage, eliminating the possibility of overflow of the steam-air mixture in the zone of low pressure.

2. U-shaped tubes are used in ejector coolers, which eliminates the possibility of thermal stress accumulation due to thermal expansion of the pipes.

3. Swivel adapter pipe provides minimal gas-dynamic resistance, reliability and durability of the structure, eliminates the accumulation of condensate and erosive wear of the pipe.

4. In the steam-jet apparatus, a design is used that allows you to change the axial distance between the nozzle and the diffuser by moving the nozzle by installing spacer rings. Such a device is necessary for adjusting the operation of the ejector during its operation, which will improve the characteristics of the ejector. To change the position of the nozzle, the working steam supply pipe is disconnected from the steam-jet apparatus, the cover is removed, under which there is a nozzle sandwiched between the spacer rings. By moving the spacer rings up or down, you can change the position of the nozzle on the axis. The nozzle fixing structure is shown in Appendix 1 of FIG. 2. The design of the nozzle extraction device is shown in Appendix 2 of FIG. 3.

5. The location of the ejector coolers in the shape of a triangle allows to reduce the space required for the ejector of the space of the industrial premises and to reduce, accordingly, the costs of the construction of thermal power plants. The layout of the ejector is shown in Appendix 3 of FIG. four.

6. The same diameters of the coolers provide the unification of parts, which increases the maintainability of the ejector.

The technical result of the utility model is an increase in the reliability and overall performance of a three-stage steam-jet ejector, in particular:

increase in working efficiency due to the possibility of setting the operating mode of the ejector depending on the conditions of its operation;

increased reliability of the ejector due to the design of the adapter pipes, eliminating erosion-corrosion wear;

increasing the efficiency and reliability of ejector coolers through the use of U-shaped tubes.

Claims (3)

1. Steam three-stage ejector, including, located in each stage sequentially in the direction of movement of the working steam, nozzles, receiving chambers, mixing chambers, diffusers, transition pipes and coolers, characterized in that the nozzles are made with the possibility of axial movement relative to the mixing chambers, transition pipes located below the diffusers, and the coolers are made remote, vertical with U-shaped tubes. 2. A three-stage steam jet ejector according to claim 1, characterized in that the ejector coolers are arranged triangularly relative to each other. 3. Steam three-stage ejector according to claim 1, characterized in that the diameters of the bodies of the ejector coolers are made the same.

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