High-low power vacuum pump replacement working system for generator set

Abstract

The invention discloses a high-low power vacuum pump replacement working system for a generator set, and belongs to the field of generator equipment, the high-low power vacuum pump replacement working system comprises two condensers, two main vacuum pumps and two low-power vacuum pump sets, the two condensers are respectively communicated with the two main vacuum pumps through vacuum mother pipes, and a communicating pipe is connected between the two vacuum mother pipes; the two low-power vacuum pump sets are communicated with the communicating pipe, and a water ring vacuum pump is arranged in each low-power vacuum pump set. The condensers of the two generator sets are vacuumized through respective main vacuum pumps before operation, and after the vacuum degree in the condensers meets the requirement, the condensers are switched into low-power vacuum pump sets to maintain vacuum, so that the purpose of reducing energy consumption is achieved. The unit system is provided with two sets of low-power vacuum pump sets, one set of low-power vacuum pump sets conducts daily vacuumizing work, and the other set of low-power vacuum pump sets serves as a standby to deal with the situation that the low-power vacuum pump set at the front stage is damaged or conducts daily maintenance.

Description

Technical Field

[0001] The invention belongs to the field of generator equipment, in particular to a high- and low-power vacuum pump replacement working system for a generator set. Background Art

[0002] As a key component in the auxiliary system of the generator set, the vacuum system is responsible for maintaining the vacuum environment in the unit condenser, thereby ensuring the normal operation of the turbine and condenser. The vacuum pump consumes a lot of electrical energy in the process of establishing and maintaining vacuum, and the operation mode of the traditional vacuum system usually has certain energy consumption problems.

[0003] At present, the vacuum system of the generator set mostly uses a constant power vacuum pump to operate continuously at a set pressure value. On the one hand, these vacuum pumps have a large power and continue to operate at high power after the vacuum environment reaches a stable state; on the other hand, after the vacuum degree of the unit reaches the required operating standard, it is not necessary to continue to operate at high power, resulting in a large amount of waste of electricity.

[0004] In some improvements to the vacuum system, a low-power vacuum pump is used in parallel with the main vacuum pump. When the main vacuum pump establishes vacuum for the unit, the high-power main vacuum pump is turned off and the vacuum is maintained by the low-power vacuum pump. For example, the vacuum pump model of the 135MW generator set is YM355MI-10, with a power of 90KW and an average daily power consumption of 3900kw / h. The installed low-power water ring vacuum pump has a power of only 37KW and an average daily power consumption of only about 700kw / h. At the same time, the vacuum can be maintained while ensuring the safety of the unit, ensuring full load operation.

[0005] However, there are some problems in the operation after installing a low-power water ring vacuum pump. When the air pressure in the condenser increases sharply, the load of the water ring vacuum pump increases, and it takes a certain amount of time for the main vacuum pump to start, and it is unable to handle the sudden increase in steam in time; and when the air pressure in the condenser drops sharply, the air inlet pressure of the water ring vacuum pump is too low, and the increase in water temperature and vacuum degree will cause the working water in the vacuum pump to vaporize. The process of bubble formation and bubble rupture will cause cavitation on the impeller, resulting in a reduction in the life of the equipment. Among them, the influence of steam temperature on the water ring vacuum pump is difficult to ignore and exists in the entire operation cycle of the water ring vacuum pump. Summary of the invention

[0006] The object of the present invention is to provide a high- and low-power vacuum pump replacement working system for a generator set to solve the problems raised in the above-mentioned prior art.

[0007] A high-low power vacuum pump replacement working system for a generator set is provided, comprising:

[0008] Two condensers, two main vacuum pumps and two low-power vacuum pump groups, the two condensers are connected to the two main vacuum pumps through vacuum mother pipes, a connecting pipe is connected between the two vacuum mother pipes, the two low-power vacuum pump groups are connected to the connecting pipes, and each of the two low-power vacuum pump groups is provided with a water ring vacuum pump.

[0009] As a further embodiment of the present invention: the low-power vacuum pump group also includes a Roots pump and a heat exchanger, and the Roots pump, the heat exchanger and the water ring vacuum pump are arranged in sequence along the gas flow direction.

[0010] As a further embodiment of the present invention: the air outlet end of the Roots pump is connected to the inner cavity of the heat exchanger, a reflux pipe is connected to the side wall of the heat exchanger and the reflux pipe is connected to the Roots pump, and a pressure valve is arranged on the reflux pipe.

[0011] As a further embodiment of the present invention: a cooling water coil is arranged inside the heat exchanger, and the cooling water coil includes a spiral coil near the air inlet end of the heat exchanger and a dense coil near the air outlet end of the heat exchanger. The spiral coil is a spiral coil rising in the vertical direction, and the dense coil is a layered coil formed by winding on a horizontal plane.

[0012] As a further embodiment of the present invention: a regulating valve is provided at the air outlet end of the heat exchanger.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The condensers of the two generator sets are evacuated by their respective main vacuum pumps before operation. When the vacuum degree in the condenser reaches the requirement, it is switched to a low-power vacuum pump set to maintain the vacuum, so as to reduce energy consumption. The unit system is equipped with two sets of low-power vacuum pump sets, one of which is used for daily vacuuming work, and the other is used as a backup to deal with the damage of the low-power vacuum pump set at the front desk or for daily maintenance.

[0015] 2. When the gas pressure of the two condensers increases sharply, in addition to the low-power vacuum pump group in daily operation, another low-power vacuum pump group can be started to run synchronously. The startup speed is faster than the main vacuum pump and can basically meet the requirements of vacuum pumping. When the gas pressure and vacuum degree of the two condensers are both at a low state, only one low-power vacuum pump group is used for vacuum pumping, and the gas-steam mixture of the two condensers can be superimposed to reduce the vaporization of working water caused by the low gas pressure at the inlet end of the water ring vacuum pump, thereby reducing the cavitation caused by vaporization. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0017] Figure 1 It is a schematic diagram of the overall structure of the high and low power vacuum pump replacement working system for the generator set;

[0018] Figure 2 This is a schematic structural diagram of the heat exchanger provided by the present invention.

[0019] In the figure: 1. Condenser; 2. Main vacuum pump; 3. Low-power vacuum pump group; 31. Water ring vacuum pump; 32. Roots pump; 33. Heat exchanger; 331. Spiral coil; 332. Dense coil; 34. Reflux pipe; 341. Pressure valve; 35. Regulating valve; 4. Vacuum main pipe; 5. Connecting pipe. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0021] Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0022] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0023] See also Figure 1-2 As shown, the generator set in the embodiment of the present invention uses a high- and low-power vacuum pump replacement working system, including two condensers 1, two main vacuum pumps 2 and two low-power vacuum pump groups 3. The two condensers 1 are respectively connected to the two main vacuum pumps 2 through a vacuum mother pipe 4, a connecting pipe 5 is connected between the two vacuum mother pipes 4, and the two low-power vacuum pump groups 3 are respectively connected to the connecting pipe 5. A water ring vacuum pump 31 is provided in each of the two low-power vacuum pump groups 3.

[0024] In one embodiment, a single condenser 1 with a rated exhaust flow rate of 289t / h is selected, and a single 45KW water ring vacuum pump 31 is selected. The vacuum main pipes 4 of the condensers 1 of the two units are connected through a connecting pipe 5. At the same time, a connecting valve is installed on the connecting pipe 5 to connect with the two water ring vacuum pumps 31, and a drain pipe is installed at the bottom of the vacuum main pipe 4 to the drain. After the main vacuum pump 2 establishes the vacuum environment of the corresponding condenser 1, the single water ring vacuum pump 31 can meet the ability to simultaneously draw vacuum from the condensers 1 of the two units. During the startup of the unit, the connecting valve on the connecting pipe 5 is closed, and the vacuum is established by the main vacuum pumps 2 of the two units respectively. After the vacuum is established, the connecting valve is opened, and the low-power water ring vacuum pump 31 is started after the grid is connected, and then the high-power main vacuum pumps 2 of the two units are stopped respectively to observe the vacuum change trend. There is almost no obvious change in the vacuum before and after the comparison, which means that a single water ring vacuum pump 31 can meet the normal load requirements of the two condensers 1. On the contrary, if a single water ring vacuum pump 31 cannot meet the vacuum maintenance requirements, another water ring vacuum pump 31 is turned on for synchronous operation.

[0025] Since the gas-steam mixture in the condenser 1 still has a relatively high temperature, the working water temperature in the pump will be significantly increased when the water ring vacuum pump 31 extracts steam. In addition, the heat generated by the operation of the pump itself will eventually increase the cavitation of the working water, and the limit vacuum and suction capacity will decrease. Therefore, a Roots pump 32 and a heat exchanger 33 are provided in the low-power vacuum pump group 3, and the Roots pump 32, the heat exchanger 33 and the water ring vacuum pump 31 are arranged in sequence along the gas flow direction.

[0026] The Roots pump 32 squeezes air through two rotors to form a large pressure difference area at both ends of the pump body. The Roots pump 32 actively extracts steam into the heat exchanger 33. After condensation and cooling in the heat exchanger 33, the gas establishes a high-pressure area at the inlet of the water ring vacuum pump 31. By lowering the gas temperature and increasing the inlet pressure, the vaporization of the working water inside the water ring vacuum pump 31 can be reduced, thereby reducing the cavitation effect of the working water on the blades inside the pump.

[0027] Furthermore, the gas outlet end of the Roots pump 32 is connected to the inner cavity of the heat exchanger 33, and a return pipe 34 is connected to the side wall of the heat exchanger 33, and the return pipe 34 is connected to the Roots pump 32, and a pressure valve 341 is provided on the return pipe 34. The pressure valve 341 can be opened after the gas in the return pipe 34 reaches the rated gas pressure. When the temperature of the gas-gas mixture is high, the heat exchanger 33 may not be able to completely cool the gas, resulting in high-temperature gas flowing into the water ring vacuum pump 31. The purpose of setting the return pipe 34 is that the gas enters the heat exchanger 33 after being pressurized by the Roots pump 32. Since the gas temperature is high and it is impossible to cool down in time, the gas pressure in the heat exchanger 33 increases, and the high-pressure gas rushes through the pressure valve 341 to re-enter the Roots pump 32 for pressurization and then enters the heat exchanger 33 for secondary cooling. The gas after secondary cooling is then transported to the water ring vacuum pump 31 to reduce the impact of the high-temperature gas on the water ring vacuum pump 31.

[0028] In order to control the flow rate of high-temperature gas between the end of the return pipe 34 and the outlet end of the heat exchanger 33, a regulating valve 35 is provided at the outlet end of the heat exchanger 33. The regulating valve 35 can adjust the rate of gas delivery to the water ring vacuum pump 31. When the gas temperature in the heat exchanger 33 is too high and the gas cannot be cooled in time, the gas outlet rate of the regulating valve 35 is reduced to increase the flow rate of the gas from the end of the return pipe 34, and then the reflux ratio of the gas is increased, so that more gas participates in the cooling process and improves the condensation effect of steam. In addition, when the gas-steam mixture of the two condensers 1 is small, even if the Roots pump 32 is pressurized, the gas will still lose some pressure after entering the heat exchanger 33. At this time, the regulating valve 35 can be adjusted to reduce the valve, so that the gas pressure in the heat exchanger 33 increases to a certain extent before opening the regulating valve 35 to ensure that the gas flowing to the water ring vacuum pump 31 is always in a high-pressure state.

[0029] The heat exchanger 33 is provided with a cooling water coil inside, and the cooling water coil includes a spiral coil 331 near the air inlet end of the heat exchanger 33 and a dense coil 332 near the air outlet end of the heat exchanger 33. The spiral coil 331 is a spiral coil that rises in the vertical direction to increase the contact area with the gas in the vertical direction and improve the heat exchange efficiency. The dense coil 332 is a layered coil formed by winding on a horizontal plane. The continuous pipes are arranged closely in sequence on a single horizontal plane. Multiple layers of coils can be set to increase the contact area with the gas. In addition, it is used to form a partial seal at the air outlet end of the heat exchanger 33, increase the internal air pressure of the heat exchanger 33, and drive the gas from the return pipe 34 to re-enter the Roots pump 32 and flow into the heat exchanger 33 for secondary cooling when the gas is at a high temperature.

[0030] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A high and low power vacuum pump replacement working system for a generator set, characterized in that: include: Two condensers (1), two main vacuum pumps (2) and two low-power vacuum pump groups (3); the two condensers (1) are respectively connected to the two main vacuum pumps (2) via a vacuum mother pipe (4); a connecting pipe (5) is connected between the two vacuum mother pipes (4); the two low-power vacuum pump groups (3) are respectively connected to the connecting pipe (5); and a water ring vacuum pump (31) is provided in each of the two low-power vacuum pump groups (3).

2. A high and low power vacuum pump replacement working system for a generator set according to claim 1, characterized in that: The low-power vacuum pump group (3) further comprises a Roots pump (32) and a heat exchanger (33), wherein the Roots pump (32), the heat exchanger (33) and the water ring vacuum pump (31) are arranged in sequence along the gas flow direction.

3. A high and low power vacuum pump replacement working system for a generator set according to claim 2, characterized in that: The air outlet end of the Roots pump (32) is in communication with the inner cavity of the heat exchanger (33), a return pipe (34) is in communication with the side wall of the heat exchanger (33), and the return pipe (34) is in communication with the Roots pump (32), and a pressure valve (341) is provided on the return pipe (34).

4. A high and low power vacuum pump replacement working system for a generator set according to claim 3, characterized in that: A cooling water coil is arranged inside the heat exchanger (33), and the cooling water coil includes a spiral coil (331) near the air inlet end of the heat exchanger (33) and a dense coil (332) near the air outlet end of the heat exchanger (33), wherein the spiral coil (331) is a spiral coil rising in the vertical direction, and the dense coil (332) is a layered coil formed by winding on a horizontal plane.

5. A high and low power vacuum pump replacement working system for a generator set according to claim 3, characterized in that: The air outlet end of the heat exchanger (33) is provided with a regulating valve (35).

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