Efficient energy-saving vacuum unit for condenser of thermal power plant

Abstract

The high-efficiency energy-saving vacuum unit comprises a main roots pump and a middle roots pump, an outlet of the main roots pump is connected with an inlet of the middle roots pump through a pipeline, an outlet of the middle roots pump is connected with an interstage cooler through a pipeline, the interstage cooler is connected with a two-stage liquid ring pump through a pipeline, and the two-stage liquid ring pump is connected with a vacuum pump through a pipeline. The two-stage liquid ring pump is connected with the gas-liquid separator through a pipeline; the main roots pump, the middle roots pump and the two-stage liquid ring pump are connected with a control cabinet through wires; and the main roots pump and the middle roots pump are also connected with a cold water inlet pipe and a cold water outlet pipe through pipelines. According to the structure provided by the embodiment of the invention, the two-stage liquid ring pump runs under the normal working condition, the compression stroke is carried out in two steps through the two-stage impeller in the two-stage liquid ring pump, the probability of small bubble blasting is greatly reduced, and cavitation can be effectively reduced; the two-stage liquid ring pump transfers compression heat to the working liquid in two times, so that the temperature rise of the working liquid of the two-stage liquid ring pump is small.

Description

Technical Field

[0001] The present application relates to the technical field of vacuum units, and in particular to a high-efficiency and energy-saving vacuum unit for a condenser in a thermal power plant. Background Art

[0002] Power plants, also known as power stations, are facilities that convert various primary energy sources found in nature into electrical energy (secondary energy). With the growing demand for electricity, the idea of ​​establishing power production centers has emerged. Advances in motor manufacturing technology, the expansion of electrical energy applications, and the rapid growth in demand for electricity have necessitated the emergence of power plants. Power plants utilize a variety of power generation methods: thermal power plants, hydropower plants, and others that rely on solar (photovoltaic) power, wind power, and tidal power.

[0003] Because the traditional vacuum equipment in power plants is liquid ring vacuum pumps, some power plants only use a combination of single-stage Roots and single-stage liquid ring vacuum pumps for energy saving. The vacuum pump rotor of the single-stage liquid ring vacuum pump is prone to cavitation and the vacuum degree is relatively low, which makes the pumping speed of the liquid ring vacuum pump decay more in the high vacuum range. Therefore, we proposed a high-efficiency and energy-saving vacuum unit for the condenser of thermal power plants. Utility Model Content

[0004] The present application provides a high-efficiency and energy-saving vacuum unit for a condenser of a thermal power plant to solve the above-mentioned problems.

[0005] The present application provides a high-efficiency and energy-saving vacuum unit for a condenser in a thermal power plant, comprising:

[0006] A main Roots pump and an intermediate Roots pump, wherein the outlet of the main Roots pump is connected to the inlet of the intermediate Roots pump via a pipeline, the outlet of the intermediate Roots pump is connected to an interstage cooler via a pipeline, the interstage cooler is connected to a two-stage liquid ring pump via a pipeline, and the two-stage liquid ring pump is connected to a gas-liquid separator via a pipeline;

[0007] The main Roots pump, the intermediate Roots pump and the two-stage liquid ring pump are all connected to the control cabinet through wires;

[0008] The main Roots pump and the intermediate Roots pump are also connected to a cold water inlet pipe and a cold water outlet pipe through pipelines;

[0009] The cold water inlet pipe is also provided with a cooling water booster pump, which is connected to a working fluid cooler through a pipeline. The working fluid cooler is connected to a cold water outlet pipe, and the working fluid cooler is also connected to a two-stage liquid ring pump and a gas-liquid separator.

[0010] Preferably, the inlet of the main Roots pump is connected to the air intake pipe, and the air intake pipe is provided with a pressure transmitter and a pneumatic butterfly valve, and the pressure transmitter and the pneumatic butterfly valve are both connected to the control cabinet through wires.

[0011] Preferably, a control valve is provided at the water inlet end of the cold water inlet pipe, and the control valve is connected to the control cabinet via a wire.

[0012] Preferably, the cooling water boost pump wires are connected to a control cabinet.

[0013] Preferably, the sewage outlets of the two-stage liquid ring pump, the interstage cooler and the gas-liquid separator are connected to the sewage pipeline through pipelines.

[0014] Preferably, a magnetic flap level gauge and a water supply pipe are provided on the outside of the gas-liquid separator, and a water supply valve is also provided on the water supply pipe. The magnetic flap level gauge and the water supply valve are connected to the control cabinet through wires.

[0015] Preferably, the interstage cooler is connected to a cold water inlet pipe and a cold water outlet pipe.

[0016] Preferably, the upper end of the gas-liquid separator is also connected to an exhaust pipe.

[0017] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0018] The structure provided in the embodiment of the present application is that the two-stage liquid ring pump operates under normal working conditions with a suction pressure of 3.4 KPa (a) and is discharged at an absolute pressure of 101.3 KPa (a). The two-stage liquid ring pump divides this compression stroke into two steps. The first stage compresses the gas to about 20.4 KPa (a), and the second stage compresses the gas to about 101.3 KPa (a) and discharges it. In this way, the compression ratio of the gas in the two-stage liquid ring pump is only 1:6 and 1:5. Therefore, the probability of small bubble bursting is greatly reduced, and the two-stage liquid ring pump can effectively resist cavitation.

[0019] The two-stage liquid ring pump completes the compression of the gas in two steps, with a small compression ratio, and the heat generated by the gas compression is very small. At the same time, the two-stage liquid ring pump transfers the compression heat to the working fluid in two steps, so the temperature rise of the working fluid of the two-stage liquid ring pump is small. Therefore, for the same working environment, the working fluid temperature inside the two-stage liquid ring pump is relatively low, so the two-stage liquid ring pump can achieve a higher vacuum degree. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0022] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0023] In the figure: 1. Main Roots pump; 2. Intermediate Roots pump; 3. Two-stage liquid ring pump; 4. Gas-liquid separator; 5. Interstage cooler; 6. Working fluid cooler; 7. Cooling water booster pump. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0025] The various embodiments of the present application may be presented in the form of a range. It should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the present application. Therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, regardless of the range. In addition, whenever a numerical range is indicated in this application, it is intended to include any quoted number (fraction or integer) within the indicated range. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in this application are all commercially available or can be prepared using existing equipment.

[0026] In this application, unless otherwise specified, the directional words used, such as "upper" and "lower", specifically refer to the directions of the drawings in the accompanying drawings. In addition, in this application, the terms "including", "comprising", etc. mean "including but not limited to". In this application, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. In this application, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this application, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c" or "at least one of a, b and c" can both mean: a, b, c, ab, i.e. a and b, ac, bc or abc, where a, b, c can be single or multiple.

[0027] like Figure 1 As shown, the embodiment of the present application provides a high-efficiency and energy-saving vacuum unit for a condenser of a thermal power plant, comprising:

[0028] A main Roots pump 1 and an intermediate Roots pump 2, wherein the outlet of the main Roots pump 1 is connected to the inlet of the intermediate Roots pump 2 via a pipeline, the outlet of the intermediate Roots pump 2 is connected to an interstage cooler 5 via a pipeline, the interstage cooler 5 is connected to a two-stage liquid ring pump 3 via a pipeline, and the two-stage liquid ring pump 3 is connected to a gas-liquid separator 4 via a pipeline;

[0029] The main Roots pump 1, the intermediate Roots pump 2 and the two-stage liquid ring pump 3 are all connected to the control cabinet through wires. The control cabinet adopts the existing control cabinet on the market, which is the existing technology, and the various control devices inside it adopt the existing control devices on the market, which are the existing technology, to control the operation of the entire set of equipment;

[0030] The main Roots pump 1 and the intermediate Roots pump 2 are also connected to a cold water inlet pipe and a cold water outlet pipe through a pipeline;

[0031] The cold water inlet pipe is also provided with a cooling water booster pump 7, and the cooling water booster pump 7 is connected to the working fluid cooler 6 through a pipeline. The working fluid cooler 6 is connected to the cold water outlet pipe, and the working fluid cooler 6 is also connected to the two-stage liquid ring pump 3 and the gas-liquid separator 4.

[0032] Specifically: When the working fluid of the water ring absorbs compression heat and its temperature rises, the closer it is to the temperature of the saturated air being pumped, the higher the probability of cavitation. In order to prevent the compression heat from being absorbed by the working fluid and causing a large temperature rise, the two-stage liquid ring pump 3 divides the gas compression into two stages. In this way, the compression heat is transferred to the sealing liquid twice, effectively controlling the temperature rise of the sealing water.

[0033] And the two-stage liquid ring pump 3 reduces the compression ratio of the pumped gas, which is the key to solving the cavitation problem of the two-stage liquid ring pump 3. Under high vacuum, a large amount of water vaporizes to form small bubbles. These small bubbles adhere to the surface of the impeller of the two-stage liquid ring pump 3. When the two-stage liquid ring pump 3 is in the compression stroke, the surface tension of the small bubbles cannot withstand the external pressure and explodes. Over the years, a large number of needle-shaped holes are formed on the surface of the impeller, which is what we call cavitation. If the two-stage liquid ring pump 3 operates under normal working conditions, the suction pressure is 3.4Kpa (a), and it is emptied at an absolute pressure of 101.3Kpa (a). The two-stage liquid ring pump 3 bipolar divides this compression stroke into two steps. The first stage compresses the gas to about 20.4Kpa (a), and the second stage compresses the gas to about 101.3Kpa (a) and discharges it. In this way, the compression ratio of the gas in the two-stage liquid ring pump 3 is only about 1:6 and 1:5. Therefore, the probability of small bubble bursting is greatly reduced, so the two-stage liquid ring pump 3 can effectively reduce cavitation.

[0034] Under normal circumstances, the ultimate vacuum of a single-stage Roots vacuum pump plus a water ring vacuum pump is 250 Pa, while the ultimate vacuum of a two-stage Roots vacuum pump plus a water ring pump is 25 Pa. However, the vacuum degree that a two-stage liquid ring pump can achieve depends on the temperature of the working fluid. Therefore, the temperature rise of the working fluid must be effectively reduced to enable the two-stage liquid ring pump 3 to achieve a higher vacuum, so that the compression ratio of the intermediate Roots pump can be smaller. The temperature rise of the working fluid is mainly caused by the heat released by steam condensation, the heat generated by mechanical rotation, and the heat generated by gas compression. Among them, the heat generated by gas compression accounts for the vast majority. The two-stage liquid ring pump 3 completes the compression of the gas in two steps, with a small compression ratio and very little heat generated by gas compression. At the same time, the two-stage liquid ring pump 3 transfers the compression heat to the working fluid in two steps. Therefore, the temperature rise of the working fluid in the two-stage liquid ring pump 3 is small. Therefore, for the same working environment, the working fluid temperature inside the two-stage liquid ring pump 3 is relatively low, so the two-stage liquid ring pump 3 can achieve a higher vacuum degree.

[0035] Specifically, two-stage Roots plus two-stage water ring vacuum units and single-stage water ring vacuum units are designed and developed for different operating conditions. Performance shows that single-stage water ring vacuum units experience severe pumping speed degradation within the higher vacuum range (less than 20 kPa), reaching less than 30% of the maximum pumping speed at 5 to 10 kPa. Under these operating conditions, efficiency is extremely low and power consumption is high. However, their greatest advantage is demonstrated under rough vacuum conditions. Two-stage Roots plus two-stage water ring vacuum units, on the other hand, can achieve even greater pumping speeds within a higher vacuum range, or maintain a high vacuum within a wide range of pumping speeds. Under higher vacuum conditions, efficiency is 35% to 40% higher than that of single-stage water ring pumps, and energy consumption is correspondingly reduced.

[0036] like Figure 1 As shown: the inlet of the main Roots pump 1 is connected to the suction pipe, and the suction pipe is provided with a pressure transmitter and a pneumatic butterfly valve. The pressure transmitter and the pneumatic butterfly valve are connected to the control cabinet through wires, and the cooling water booster pump 7 is connected to the control cabinet through wires.

[0037] Specifically, a power supply and various controllers are installed inside the control cabinet to control the working status of the pressure transmitter, pneumatic butterfly valve, main Roots pump 1, intermediate Roots pump 2, and cooling water booster pump 7.

[0038] As shown in Figure 1: a control valve is provided at the water inlet end of the cold water inlet pipe, and the control valve is connected to the control cabinet via a wire.

[0039] Specifically: the switch status of the control valve is controlled inside the control cabinet.

[0040] like Figure 1 As shown: the sewage outlets of the two-stage liquid ring pump 3, the interstage cooler 5 and the gas-liquid separator 4 are connected to the sewage pipeline through pipelines.

[0041] Specifically, waste from the two-stage liquid ring pump 3, the interstage cooler 5 and the gas-liquid separator 4 is discharged into the sewage pipe.

[0042] like Figure 1 As shown: a magnetic flap level gauge and a water supply pipe are provided on the outside of the gas-liquid separator 4, and a water supply valve is also provided on the water supply pipe. The magnetic flap level gauge and the water supply valve are connected to the control cabinet through wires.

[0043] Specifically: the magnetic flap level gauge and water supply valve are controlled by the control cabinet.

[0044] like Figure 1 As shown: the interstage cooler 5 is connected to the cold water inlet pipe and the cold water outlet pipe; the upper end of the gas-liquid separator 4 is also connected to the exhaust pipe.

[0045] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but rather is intended to conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A high-efficiency and energy-saving vacuum unit for a condenser in a thermal power plant, characterized in that: include: A main Roots pump (1) and an intermediate Roots pump (2), wherein the outlet of the main Roots pump (1) is connected to the inlet of the intermediate Roots pump (2) via a pipeline, the outlet of the intermediate Roots pump (2) is connected to an interstage cooler (5) via a pipeline, the interstage cooler (5) is connected to a two-stage liquid ring pump (3) via a pipeline, and the two-stage liquid ring pump (3) is connected to a gas-liquid separator (4) via a pipeline; The main Roots pump (1), the intermediate Roots pump (2) and the two-stage liquid ring pump (3) are all connected to the control cabinet via wires; The main Roots pump (1) and the intermediate Roots pump (2) are also connected to a cold water inlet pipe and a cold water outlet pipe via a pipeline; The cold water inlet pipe is also provided with a cooling water booster pump (7), the cooling water booster pump (7) is connected to a working fluid cooler (6) via a pipeline, the working fluid cooler (6) is connected to a cold water outlet pipe, and the working fluid cooler (6) is also connected to a two-stage liquid ring pump (3) and a gas-liquid separator (4).

2. The high-efficiency energy-saving vacuum unit for a condenser in a thermal power plant according to claim 1, characterized in that: The inlet of the main Roots pump (1) is connected to an air intake pipe, and a pressure transmitter and a pneumatic butterfly valve are provided on the air intake pipe. The pressure transmitter and the pneumatic butterfly valve are both connected to a control cabinet via wires.

3. The high-efficiency energy-saving vacuum unit for a condenser in a thermal power plant according to claim 1, characterized in that: A control valve is provided at the water inlet end of the cold water inlet pipe, and the control valve is connected to the control cabinet through a wire.

4. The high-efficiency energy-saving vacuum unit for a condenser in a thermal power plant according to claim 1, characterized in that: The cooling water booster pump (7) is connected to the control cabinet through a wire.

5. The high-efficiency energy-saving vacuum unit for a condenser in a thermal power plant according to claim 1, characterized in that: The sewage outlets of the two-stage liquid ring pump (3), the interstage cooler (5) and the gas-liquid separator (4) are connected to the sewage pipeline through pipelines.

6. The high-efficiency energy-saving vacuum unit for a condenser in a thermal power plant according to claim 1, characterized in that: A magnetic flap level gauge and a water supply pipe are provided on the outside of the gas-liquid separator (4), and a water supply valve is also provided on the water supply pipe. The magnetic flap level gauge and the water supply valve are both connected to the control cabinet via wires.

7. The high-efficiency energy-saving vacuum unit for a condenser in a thermal power plant according to claim 1, characterized in that: The interstage cooler (5) is connected to a cold water inlet pipe and a cold water outlet pipe.

8. The high-efficiency energy-saving vacuum unit for a condenser in a thermal power plant according to claim 1, characterized in that: The upper end of the gas-liquid separator (4) is also connected to an exhaust pipe.

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