Automatic humidifying system of centrifugal compressor

Abstract

The invention discloses an automatic humidifying system of a centrifugal compressor, which comprises a constant-temperature water tank arranged at a high position and forming a height difference with an impeller of the compressor to provide a pressure water source, and a water tank drain valve mounted at the bottom of the constant-temperature water tank; the automatic make-up pump is connected to the constant-temperature water tank and used for keeping the liquid level of the water tank constant; and the water tank heater is arranged in the constant-temperature water tank and used for adjusting the water temperature to a target range of + / -10 DEG C. According to the automatic humidification system of the centrifugal compressor, the optimal pressure set value can be determined through system debugging, the humidification flow is dynamically matched with the operation working condition of the compressor, and compared with traditional PID control, the system structure is simplified. The self-operated pressure regulating valve is used, the humidifying flow is controlled through a pure mechanical structure, and the system is simple and reliable. The water collecting chamber is arranged in front of the atomizing nozzle so as to ensure the stability of the pressure in front of the atomizing nozzle, and the pressure tapping port of the self-operated pressure regulating valve is arranged in the water collecting chamber, so that the influence of flow velocity fluctuation on pressure regulation due to pressure tapping on a pipeline is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pumps, and particularly to an automatic humidification system for a centrifugal compressor. Background Art

[0002] A centrifugal compressor is one of the power machines in the industrial field and is widely used in fields such as refrigeration, energy storage, and heat pumps, mainly for air compression, steam compression, and compression of other working fluids. When not using a cooling method, heat cannot be dissipated in time, so this process is close to an isentropic process. As the pressure increases, the temperature of the working fluid also increases, which also causes an increase in power consumption. For a compression process with the same pressure ratio, the power consumption of isothermal compression is the lowest. Therefore, reducing the exhaust temperature is an effective means to improve compression efficiency and reduce compression power consumption. On the other hand, reducing the exhaust temperature is beneficial to the mechanical strength of the impeller, bearing lubrication, etc. Especially in the heat pump field, the industry is committed to developing high-temperature heat pumps with an exhaust temperature above 100°C. To solve the over-temperature problem caused by too high an exhaust temperature, it is very necessary to cool the compression process.

[0003] The current humidification methods are usually inlet humidification and inter-stage humidification of the compressor. The humidification processes used are usually manual valve control or closed-loop control using a controller, etc. With the development of technology, various humidification methods such as hub humidification and flow passage humidification have gradually emerged, making humidification cooling more refined, and the corresponding humidification processes also need to be adjusted and optimized. Summary of the Invention

[0004] The purpose of the present invention is to provide an automatic humidification system for a centrifugal compressor to solve the problems such as the humidification process usually being manual valve control or closed-loop control using a controller as proposed in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: An automatic humidification system for a centrifugal compressor, comprising:

[0006] A constant temperature water tank, arranged at a high position, forming a height difference with the compressor impeller to provide a pressurized water source, and a water discharge valve is installed at the bottom of the constant temperature water tank;

[0007] An automatic make-up water pump, connected to the constant temperature water tank, for maintaining the constant water level in the tank;

[0008] A water tank heater, arranged in the constant temperature water tank, for adjusting the water temperature to the target range of ±10°C;

[0009] A low-pressure humidification pipeline, including a manual valve before the self-acting regulating valve, a self-acting pressure regulating valve for the low-pressure humidification pipeline, a manual valve after the regulating valve, a check valve, a steam trap, a low-pressure humidification pipeline water collecting chamber, and atomizing holes connected in sequence;

[0010] The high-pressure humidification pipeline includes a manual valve before the self-acting regulating valve, a self-acting pressure regulating valve for the high-pressure humidification pipeline, a manual valve after the regulating valve, a check valve, a steam trap, a water collecting chamber of the high-pressure humidification pipeline, and atomizing holes, which are connected in sequence.

[0011] The pressure signal acquisition unit includes a pressure tapping pipe for the self-acting pressure regulating valve of the low-pressure humidification pipeline and a pressure tapping pipe for the self-acting pressure regulating valve of the high-pressure humidification pipeline, which collect static pressure signals from the water collecting chamber of the low-pressure humidification pipeline and the water collecting chamber of the high-pressure humidification pipeline respectively, and feedback them to the self-acting pressure regulating valve of the low-pressure humidification pipeline and the self-acting pressure regulating valve of the high-pressure humidification pipeline.

[0012] The compressor impeller is provided with low-pressure humidification atomizing holes and high-pressure humidification atomizing holes in its flow passage.

[0013] The thermocouple at the compressor outlet is used to monitor the temperature of the working medium at the outlet and assist in judging the operating state of the humidification system.

[0014] Preferably, the self-acting pressure regulating valves for the low-pressure humidification pipeline and the high-pressure humidification pipeline are of the type that regulates the pressure after the valve, and their target pressure values (P21, P22) are determined through debugging. Specifically:

[0015] The initial setting value is the theoretical pressure (P21, P22) calculated according to the flow rate of the atomizing nozzle.

[0016] By adjustment, the actual flow rate of the atomizing nozzle reaches the optimal value, and the corresponding pressure value at this time is the final setting value (P21, P22).

[0017] Preferably, the water collecting chamber of the low-pressure humidification pipeline and the water collecting chamber of the high-pressure humidification pipeline are annular cavities. The water collecting chamber (11) of the low-pressure humidification pipeline is integrated at the end of the rotor at the inlet of the flow passage, and low-pressure humidification atomizing holes are arranged circumferentially on the inner wall surface of the rotor to uniformly spray water mist into the flow passage; the water collecting chamber (20) of the high-pressure humidification pipeline is integrated outside the compressor wheel cover, and high-pressure humidification atomizing holes (25) are arranged circumferentially at the wheel cover to uniformly spray water mist into the flow passage.

[0018] Preferably, the bypass valves of the self-acting regulating valves for the low-pressure humidification pipeline and the high-pressure humidification pipeline are used to switch to bypass operation when the self-acting regulating valves fail.

[0019] Preferably, the height difference design of the constant temperature water tank meets the requirements of the inlet pressure of the self-acting regulating valve, and the water level fluctuation range is controlled within the design range by an automatic makeup water pump.

[0020] Preferably, the check valves for the low-pressure humidification pipeline and the high-pressure humidification pipeline are used to prevent the working medium from flowing back to the water supply pipeline when the pressures in the water collecting chamber of the low-pressure humidification pipeline and the water collecting chamber of the high-pressure humidification pipeline rise abnormally.

[0021] Preferably, the low-pressure humidification pipeline steam trap and the high-pressure humidification pipeline steam trap are opened during system maintenance to drain the accumulated water in the pipeline and are in a closed state during normal operation.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] The automatic humidification system of the centrifugal compressor adopts a self-acting pressure regulating valve to achieve a pure mechanical closed-loop control. A stable static pressure signal is obtained through the water collection chamber to avoid the interference of pipeline flow velocity fluctuations on pressure regulation and ensure the accurate constancy of the pressure before the atomizing nozzle. The optimal pressure setting value can be determined through system debugging to dynamically match the humidification flow rate with the operating conditions of the compressor, simplifying the system structure compared with the traditional PID control. By using a self-acting pressure regulating valve, the pure mechanical structure controls the humidification flow rate, and the system is simple and reliable. A water collection chamber is arranged in front of the atomizing nozzle to ensure the stability of the pressure before the atomizing nozzle. The pressure tapping port of the self-acting pressure regulating valve is set in the water collection chamber to avoid the influence on pressure regulation caused by flow velocity fluctuations when tapping pressure on the pipeline. Description of the Drawings

[0024] Figure 1 It is the wet compression process diagram of the centrifugal compressor of the present invention;

[0025] Figure 2 It is the schematic diagram of the impeller cover structure of the centrifugal compressor of the present invention.

[0026] In the figure: 1, constant temperature water tank; 2, water tank heater; 3, water tank drain valve; 4, automatic makeup water pump; 5, manual valve before the self-acting regulating valve of the low-pressure humidification pipeline; 6, self-acting pressure regulating valve of the low-pressure humidification pipeline; 7, manual valve after the self-acting regulating valve of the low-pressure humidification pipeline; 8, check valve of the low-pressure humidification pipeline; 9, bypass valve of the self-acting regulating valve of the low-pressure humidification pipeline; 10, steam trap of the low-pressure humidification pipeline; 11, water collection chamber of the low-pressure humidification pipeline; 12, low-pressure humidification pipeline; 13, pressure tapping pipe of the self-acting pressure regulating valve of the low-pressure humidification pipeline; 14, manual valve before the self-acting regulating valve of the high-pressure humidification pipeline; 15, self-acting pressure regulating valve of the high-pressure humidification pipeline; 16, manual valve after the self-acting regulating valve of the high-pressure humidification pipeline; 17, check valve of the high-pressure humidification pipeline; 18, bypass valve of the self-acting regulating valve of the high-pressure humidification pipeline; 19, steam trap of the high-pressure humidification pipeline; 20, water collection chamber of the high-pressure humidification pipeline; 21, high-pressure humidification pipeline; 22, pressure tapping pipe of the self-acting pressure regulating valve of the high-pressure humidification pipeline; 23, compressor impeller; 24, low-pressure humidification atomizing holes; 25, high-pressure humidification atomizing holes; 26, thermocouple at the compressor outlet. Detailed Embodiments

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Please refer to Figure 1-2 , the present invention provides a technical solution: an automatic humidification system for a centrifugal compressor, including:

[0029] A constant temperature water tank 1, arranged at a high position, forms a height difference with the compressor impeller 23 to provide a pressurized water source. The specific height difference depends on the type selection of the self-acting regulating valve to ensure that the inlet pressure requirement of the self-acting regulating valve is met; and the water level fluctuation range of the constant temperature water tank 1 is controlled within the design range by the automatic makeup water pump 4. A water tank drain valve 3 is installed at the bottom of the constant temperature water tank 1. The normal working valve position of the water tank drain valve 3 is the closed position, and this valve is opened when the water tank needs to be drained, usually used during system maintenance or when cleaning the water tank;

[0030] An automatic makeup water pump 4, which automatically makes up water after the liquid level drops, is connected to the constant temperature water tank 1 and is used to maintain the constant water level of the water tank. By automatically making up water, the water level in the water tank is ensured to be within the design range to ensure that the water level difference is fixed, so that the pressure in front of the self-acting regulating valve is constantly P1;

[0031] A water tank heater 2, arranged in the constant temperature water tank 1, and the heater automatically adjusts according to the detected water tank temperature. According to the simulation results of CFD, the influence of the droplet temperature on the humidification effect is very small. Therefore, very precise temperature control of the water tank is not required, and there is no obvious influence on the humidification effect within ±10°C of the target water level range;

[0032] A low-pressure humidification pipeline 12, including a manual valve 5 in front of the self-acting regulating valve of the low-pressure humidification pipeline, a self-acting pressure regulating valve 6 of the low-pressure humidification pipeline, a manual valve 7 behind the self-acting regulating valve of the low-pressure humidification pipeline, a check valve 8 of the low-pressure humidification pipeline, a steam trap 10 of the low-pressure humidification pipeline, a water collecting chamber 11 of the low-pressure humidification pipeline, and a low-pressure humidification atomizing hole 24, which are connected in sequence. The water collecting chamber 11 of the low-pressure humidification pipeline and the water collecting chamber 20 of the high-pressure humidification pipeline are arranged in front of the atomizing nozzle and are cavities for storing liquid water. This cavity is externally connected to a water supply pipeline and simultaneously provides a pressure signal for the self-acting regulating valve. Obtaining a static pressure signal in the cavity is more accurate and stable than taking a pressure at an opening in the pipeline and is not easily affected by the flow rate;

[0033] The high-pressure humidification pipeline 21 includes a manual valve 14 before the self-acting regulating valve of the high-pressure humidification pipeline, a self-acting pressure regulating valve 15 of the high-pressure humidification pipeline, a manual valve 16 after the self-acting regulating valve of the high-pressure humidification pipeline, a check valve 17 of the high-pressure humidification pipeline, a steam trap 19 of the high-pressure humidification pipeline, a water collecting chamber 20 of the high-pressure humidification pipeline, and high-pressure humidification atomizing holes 25, which are connected in sequence.

[0034] Before and after the self-acting regulating valve, there are a manual valve 5 before the self-acting regulating valve of the low-pressure humidification pipeline, a manual valve 14 before the self-acting regulating valve of the high-pressure humidification pipeline, a manual valve 7 after the self-acting regulating valve of the low-pressure humidification pipeline, and a manual valve 16 after the self-acting regulating valve of the high-pressure humidification pipeline. The valves can cut off the working medium and isolate the self-acting regulating valves. The normal valve position is the open position.

[0035] The pressure signal acquisition unit includes a pressure tapping pipe 13 of the self-acting pressure regulating valve of the low-pressure humidification pipeline and a pressure tapping pipe 22 of the self-acting pressure regulating valve of the high-pressure humidification pipeline, which respectively collect static pressure signals from the water collecting chamber 11 of the low-pressure humidification pipeline and the water collecting chamber 20 of the high-pressure humidification pipeline and feedback them to the self-acting pressure regulating valve 6 of the low-pressure humidification pipeline and the self-acting pressure regulating valve 15 of the high-pressure humidification pipeline. The self-acting pressure regulating valve 6 of the low-pressure humidification pipeline and the self-acting pressure regulating valve 15 of the high-pressure humidification pipeline are of the type of regulating the pressure after the valve. Their target pressure values P21 and P22 are determined through debugging. Specifically, the initial setting values are the theoretical pressures P21 and P22 calculated according to the flow rate of the atomizing nozzle. By adjustment, the actual flow rate of the atomizing nozzle reaches the optimal value, and the corresponding pressure values at this time are the final setting values P21 and P22. The water collecting chamber 11 of the low-pressure humidification pipeline and the water collecting chamber 20 of the high-pressure humidification pipeline are annular cavities and are integrated in the compressor wheel cover.

[0036] Both the low-pressure humidification pipeline and the high-pressure humidification pipeline are provided with a bypass valve 9 of the self-acting regulating valve of the low-pressure humidification pipeline and a bypass valve 18 of the self-acting regulating valve of the high-pressure humidification pipeline, which are used to switch to bypass operation when the self-acting regulating valve fails.

[0037] The bypass valve 9 of the self-acting regulating valve of the low-pressure humidification pipeline and the bypass valve 18 of the self-acting regulating valve of the high-pressure humidification pipeline function to bypass the self-acting regulating valve. The normal state is the closed position. If the self-acting regulating valve gets stuck or has other failures during use, open this valve, close the manual valves before and after the self-acting regulating valve, and put it into short-term bypass operation. After the failure of the self-acting regulating valve is eliminated, close this valve.

[0038] The compressor impeller 23 has low-pressure humidification atomizing holes 24 and high-pressure humidification atomizing holes 25 arranged in its flow path. The check valve 8 of the low-pressure humidification pipeline and the check valve 17 of the high-pressure humidification pipeline are used to prevent the working medium from flowing back to the water supply pipeline when the pressure in the water collecting chamber 11 of the low-pressure humidification pipeline and the check valve 17 of the high-pressure humidification pipeline rises abnormally.

[0039] Water in the low-pressure humidification pipeline water collecting chamber 11 is sprayed into the flow channel through the low-pressure humidification atomizing holes 24, and the low-pressure humidification atomizing holes 24 can be arranged circumferentially in multiple places; water in the high-pressure humidification pipeline water collecting chamber 20 is sprayed into the flow channel through the high-pressure humidification atomizing holes 25, and the high-pressure humidification atomizing holes 25 can be arranged circumferentially in multiple places. The water collecting chamber is annular and integrated with the wheel cover, and is used to evenly spray water mist into the flow channel.

[0040] The compressor outlet thermocouple 26 is used to monitor the temperature of the outlet working medium and plays a role in assisting in monitoring the operating state of the humidification system. When the temperature deviates from the outlet temperature under normal operating conditions, it is necessary to check whether the humidification system has a fault.

[0041] The low-pressure humidification pipeline drain valve 10 and the high-pressure humidification pipeline drain valve 19 are opened during system maintenance to drain the accumulated water in the pipeline and are in a closed state during normal operation.

[0042] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An automatic humidification system for a centrifugal compressor, characterized in that, Including: A constant temperature water tank (1), arranged at a high position, forming a height difference with the compressor impeller (23) to provide a pressurized water source, and a water discharge valve (3) is installed at the bottom of the constant temperature water tank (1); An automatic makeup water pump (4), connected to the constant temperature water tank (1), for maintaining a constant water level in the tank; A water tank heater (2), arranged inside the constant temperature water tank (1), for adjusting the water temperature to the target range of ±10°C; A low-pressure humidification pipeline (12), including a manual valve (5) before the self-acting regulating valve, a self-acting pressure regulating valve (6) for the low-pressure humidification pipeline, a manual valve (7) after the regulating valve, a check valve (8), a steam trap (10), a low-pressure humidification pipeline water collecting chamber (11) and atomizing holes (24) connected in sequence; A high-pressure humidification pipeline (21), including a manual valve (14) before the self-acting regulating valve, a self-acting pressure regulating valve (15) for the high-pressure humidification pipeline, a manual valve (16) after the regulating valve, a check valve (17), a steam trap (19), a high-pressure humidification pipeline water collecting chamber (20) and atomizing holes (25) connected in sequence; A pressure signal acquisition unit, including a pressure tapping pipe (13) for the self-acting pressure regulating valve of the low-pressure humidification pipeline and a pressure tapping pipe (22) for the self-acting pressure regulating valve of the high-pressure humidification pipeline, which respectively collect static pressure signals from the low-pressure humidification pipeline water collecting chamber (11) and the high-pressure humidification pipeline water collecting chamber (20) and feedback them to the self-acting pressure regulating valve (6) of the low-pressure humidification pipeline and the self-acting pressure regulating valve (15) of the high-pressure humidification pipeline; A compressor impeller (23), with low-pressure humidification atomizing holes (24) and high-pressure humidification atomizing holes (25) arranged in its flow channel; A compressor outlet thermocouple (26), used for monitoring the outlet working medium temperature to assist in judging the operation state of the humidification system.

2. The automatic humidification system of a centrifugal compressor according to claim 1, characterized in that, The self-acting pressure regulating valve (6) of the low-pressure humidification pipeline and the self-acting pressure regulating valve (15) of the high-pressure humidification pipeline are of the type of regulating the pressure behind the valve, and their target pressure values (P21, P22) are determined through debugging. Specifically: The initial setting value is the theoretical pressure (P21, P22) calculated according to the flow rate of the atomizing nozzle; By adjustment, the actual flow rate of the atomizing nozzle reaches the optimal value, and the corresponding pressure value at this time is the final setting value (P21, P22).

3. The automatic humidification system for a centrifugal compressor according to claim 1, characterized in that, The low-pressure humidification pipeline water collecting chamber (11) and the high-pressure humidification pipeline water collecting chamber (20) are annular cavities. The low-pressure humidification pipeline water collecting chamber (11) is integrated at the rotor inlet end of the flow channel inlet, and low-pressure humidification atomizing holes are arranged circumferentially on the inner wall surface of the rotor to uniformly spray water mist into the flow channel; the high-pressure humidification pipeline water collecting chamber (20) is integrated outside the compressor wheel cover, and high-pressure humidification atomizing holes (25) are arranged circumferentially at the wheel cover for uniformly spraying water mist into the flow channel.

4. The system according to claim 1, wherein The bypass valve (9) of the self-acting regulating valve of the low-pressure humidification pipeline and the bypass valve (18) of the self-acting regulating valve of the high-pressure humidification pipeline are used to switch to bypass operation when the self-acting regulating valve fails.

5. The system according to claim 1, wherein The height difference design of the constant temperature water tank (1) meets the inlet pressure requirements of the self-acting regulating valve, and its water level fluctuation range is controlled within the design range by the automatic makeup water pump (4).

6. The system according to claim 1, wherein The check valves (8) of the low-pressure humidification pipeline and the check valves (17) of the high-pressure humidification pipeline are used to prevent the working medium from flowing back to the water supply pipeline when the pressures of the low-pressure humidification pipeline water collection chamber (11) and the high-pressure humidification pipeline water collection chamber (20) rise abnormally.

7. The system according to claim 1, wherein The drain valves (10) of the low-pressure humidification pipeline and the drain valves (19) of the high-pressure humidification pipeline are opened during system maintenance to drain the accumulated water in the pipeline, and are in the closed state during normal operation.

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