Gas medium leakage monitoring system for variable volume clearance cavity of reciprocating compressor

Abstract

The invention relates to a gas medium leakage monitoring system for a variable-volume clearance cavity of a reciprocating compressor, and belongs to the technical field of reciprocating compressors. The leakage monitoring system comprises a leakage monitoring pipeline and a gas detector arranged on the leakage monitoring pipeline and used for analyzing the content of target gas, one end of the leakage monitoring pipeline is used for being connected with a leakage monitoring cavity of a variable-volume clearance cavity, and the other end of the leakage monitoring pipeline is connected with a negative pressure suction inlet of a negative pressure pump; the leakage monitoring pipeline is connected with a one-way air suction structure used for sucking air. And the one-way air suction structure is arranged at the upstream of the gas detector. The monitoring system disclosed by the invention is helpful for timely and reliably finding out toxic and corrosive gas medium leakage caused by untight clearance packing sealing of the medium reciprocating compressor, and prevents personnel poisoning and equipment damage by sucking air and timely sucking out the leaked gas medium from a clearance cavity.

Description

Technical Field

[0001] The invention relates to a gas medium leakage monitoring system for a variable-volume clearance cavity of a reciprocating compressor, belonging to the technical field of reciprocating compressors. Background Art

[0002] A reciprocating compressor is a type of positive displacement compressor that uses the reciprocating motion of a piston or diaphragm within the cylinder to periodically change the cylinder volume, thereby pressurizing and transporting gas. The displacement of a reciprocating gas compressor is typically selected based on the required flow rate of the device, with a certain margin generally set. If changes in inlet conditions (inlet pressure, temperature, etc.), process flow, or demand from gas-consuming equipment cause the gas consumption to fall below the compressor's displacement, the compressor needs to be regulated to adapt the compressor's displacement to the required gas consumption and maintain pipeline pressure. To meet the requirements of compressor structure, manufacturing, assembly, and operation, certain spaces or gaps are left in certain areas of the cylinder. This space or gap is called clearance volume.

[0003] Clearance adjustment is the process of changing the distance between certain parts within the machine, such as by narrowing or widening the distance between parts, to alter the internal pressure of the compressor, thereby adjusting the compressor's operating performance. This can benefit the compressor's power consumption, the thermodynamic process of the working fluid within the cylinder, exhaust temperature, machine vibration, and the forces acting on key components. A variable volume clearance cavity (VVCP) changes the clearance cavity at the cylinder head end. The clearance amount depends on the position of the piston within the clearance cavity. Turning the variable clearance piston rod counterclockwise increases the clearance, while turning it clockwise decreases it. By varying the clearance volume, the displacement of the reciprocating compressor can be adjusted.

[0004] During the pressurized extraction of natural gas, special medium components such as hydrogen sulfide, carbon dioxide, chlorine, and hydrogen chloride are present in the gas. The variable volume clearance cavity of the compressor is sealed with a V-shaped sealing packing. When the compressor is operating normally or adjusting the volume of the clearance cavity, due to alternating forces or packing wear, some gas may always leak into the adapter cavity through the gap between the packing and the variable volume clearance piston rod, and then enter the environment through the adapter vent. During the pressurized extraction of natural gas with high hydrogen sulfide content, the above situation may cause environmental pollution or personal injury.

[0005] In the prior art, a Chinese invention patent application with application publication number CN105781957A, filed on July 20, 2016, discloses a multi-action leakage monitoring system for an actuator in a compressor clearance gas volume control system. The system includes a leakage monitoring branch line connected to the leakage monitoring cavity of each actuator, with a branch line valve provided on each leakage monitoring branch line. Each leakage monitoring branch line is connected to one end of a leakage monitoring main line, the other end of which is connected to a buffer tank valve of a public gas main network buffer tank via a main control valve. Two main line valves are spaced apart on the leakage monitoring main line, and an on-site display meter, a gas detector, and a first check valve that allows gas to pass from the leakage monitoring cavity to the public gas main network buffer tank are provided on the leakage monitoring main line between the two main line valves. However, due to the complex process and the large number of equipment, on-site layout and operation are inconvenient. Moreover, the generated toxic and corrosive gases cannot be discharged in a timely manner and tend to accumulate in the clearance cavity, which is prone to corrosion of equipment components. Summary of the Invention

[0006] The purpose of the present invention is to provide a reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system to solve the problem that the reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system has a complicated process and cannot discharge toxic and corrosive gases from the clearance cavity in time.

[0007] In order to achieve the above objectives, the technical solution adopted by the present invention is:

[0008] A reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system includes a leakage monitoring pipeline and a gas detector arranged on the leakage monitoring pipeline for analyzing the target gas content. One end of the leakage monitoring pipeline is used to be connected to the leakage monitoring cavity body of the variable volume clearance cavity, and the other end of the leakage monitoring pipeline is connected to the negative pressure suction port of a negative pressure pump; a one-way suction structure for inhaling air is connected to the leakage monitoring pipeline; the one-way suction structure is arranged upstream of the gas detector.

[0009] Furthermore, the reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system also includes a programmable controller, the gas detector is electrically connected to the programmable controller, and the programmable controller is equipped with an audible and visual alarm that issues an alarm when the content of the target gas in the leakage monitoring pipeline exceeds a set value.

[0010] Furthermore, the outlet of the negative pressure pump is connected to the venting structure.

[0011] Furthermore, the venting structure includes a venting pipeline and a target gas absorption device connected to the venting pipeline.

[0012] Furthermore, the negative pressure pump is a Venturi ejector; the inlet of the Venturi ejector is connected to a power gas source pipeline.

[0013] Furthermore, the one-way air suction structure is a one-way valve.

[0014] Furthermore, a filter is provided on the leakage detection pipeline, and the filter is located upstream of the gas detector.

[0015] The present invention provides a reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system, which improves the existing technology. A one-way suction structure for inhaling air is provided in the leakage monitoring pipeline. Under the action of a negative pressure pump, air continuously enters the leakage detection pipeline and enters the gas detector through the one-way suction structure. During this process, the gas detector monitors the concentration of the target gas in the leakage monitoring pipeline in real time online, which helps to timely and reliably detect the leakage of toxic and corrosive gas media caused by the loose sealing of the clearance packing of the medium reciprocating compressor, and uses the inhaled air to suck the leaked gas medium out of the clearance cavity in time to avoid poisoning of personnel and damage to equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a gas medium leakage monitoring system for a variable volume clearance cavity of a reciprocating compressor according to Example 1 of the present invention;

[0017] Among them, 1-leakage monitoring pipeline, 2-filter, 3-gas detector, 4-branch pipeline, 5-tee connector, 6-first one-way valve, 7-first ball valve, 8-Venturi ejector, 9-vent pipeline, 10-second one-way valve, 11-second ball valve, 12-power gas source pipeline, 13-third ball valve, 14-pressure regulating valve, 15-first flow meter, 16-third one-way valve, 17-safety valve, 18-compressor programmable controller, 19-human-machine interface, 20-fourth ball valve, 21-micro-negative pressure gauge, 22-second flow meter, 23-three-way valve, 24-closed local discharge valve, 25-collection tank, 26-instrument calibration pipeline, 27-fourth one-way valve, 28-leakage detection chamber. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described below in conjunction with specific implementation methods.

[0019] Example

[0020] The reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system of this embodiment is as follows: Figure 1As shown, it includes a leakage monitoring pipeline 1 and a filter 2 and a gas detector 3 arranged in series on the leakage monitoring pipeline 1; the leakage monitoring pipeline 1 is also provided with a branch pipeline 4, which is connected to the leakage monitoring pipeline 1 through a three-way joint 5, and the three-way joint 5 is located upstream of the filter 2 and the gas detector 3. The end of the branch pipeline 4 is provided with a first one-way valve 6 as an air intake valve, and the first one-way valve 6 can only allow external air to freely enter the leakage monitoring pipeline 1. The branch pipeline 4 is also provided with a first ball valve 7; one end of the leakage monitoring pipeline 1 is connected to the leakage monitoring cavity 28 of the variable volume clearance cavity, and the other end is connected to the negative pressure suction port of the Venturi ejector 8; the Venturi ejector The outlet is connected to one end of the vent line 9, and the vent line 9 is provided with a second one-way valve 10 and a second ball valve 11. The second ball valve 11 is located downstream of the second one-way valve 10. The second ball valve 11 is normally open to ensure that there is air circulation during the injection process of the Venturi ejector 8 when no leakage occurs; since the monitored target gases are mostly toxic and harmful gases, such as hydrogen sulfide gas, in order to reduce the harm of toxic and harmful gases to the human body and the environment, the other end of the vent line 9 can be directly connected to the vent system so that the gas enters the vent system for treatment and then vented, or the other end of the vent line can be connected to the air inlet of the target gas absorption pool to absorb the harmful gas and then vent it.

[0021] The inlet of the venturi ejector 8 is connected to one end of a power gas source pipeline 12, the other end of which is connected to a power gas source. The power gas source can be air. Air enters the venturi ejector 8 through the power gas source pipeline 12, is ejected from the nozzle of the venturi ejector 8, and is fully mixed with the gas in the leakage monitoring pipeline 1 before entering the venting pipeline 9. During this process, the air further dilutes toxic and harmful gases, reducing the harm of toxic and harmful gases to the human body and the environment. The power gas source pipeline 12 is equipped with a third ball valve 13, a pressure regulating valve 14, a first flowmeter 15, and a third check valve 16. The third ball valve 13, the pressure regulating valve 14, the first flowmeter 15, and the third check valve 16 are arranged in sequence in the direction of the power gas flow. The first flowmeter 15 can be used to monitor the normal operation of the venturi ejector 8 in real time. The venturi ejector 8 is also equipped with a safety valve 17 to prevent overpressure of the power gas source in the power gas source pipeline 12. In other embodiments of the reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system of the present invention, the Venturi ejector may be replaced by a commonly used negative pressure pump such as a Roots blower.

[0022] The gas detector 3, which is installed in series on the leakage monitoring pipeline 1, can analyze the content of the target gas in the leakage monitoring pipeline 1 in real time online. Depending on the type of target gas to be analyzed, the gas detector 3 can select a single component analysis sensor or a multi-component analysis sensor to perform real-time analysis of the content of the gas medium to be analyzed. Of course, to improve the reliability of the analysis, different types of sensors can also be selected for a single component and used in combination. The gas detector 3 is electrically connected to the control cabinet, which is equipped with a programmable controller (PLC) 18 and an audible and visual alarm that is matched with the programmable controller 18. The programmable controller 18 is electrically connected to the human-machine interface 19 of the central control room. The gas detector 3 is electrically connected to the programmable controller 18 in the control cabinet, and transmits the analyzed target gas content data in the leakage monitoring pipeline to the programmable controller 18 in the control cabinet in real time, and at the same time remotely sends the detection information to the human-machine interface 19. When the programmable controller 18 detects that the content of the target gas exceeds the set threshold, it triggers the audible and visual alarm to sound an alarm.

[0023] The filter 2 is located upstream of the gas detector 3 and can filter out particles and lubricating oil in the gas to prevent the particles and lubricating oil from affecting the sensitivity of the gas detector 3; in other embodiments of the reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system of the present invention, the filter 2 can also be omitted.

[0024] The leakage monitoring pipeline 1 also has an on-site discharge branch pipeline, a fourth ball valve 20, a micro-negative pressure gauge 21, a second flow meter 22 and a three-way valve 23 arranged in sequence in the direction of gas flow, wherein the on-site discharge branch pipeline and the fourth ball valve 20 are located upstream of the filter 3, and the on-site discharge branch pipeline can be used for emergency discharge in the event of liquid accumulation and large-scale leakage in the variable clearance cavity. A normally closed on-site discharge valve 24 is provided on the on-site discharge branch pipeline, and a collection tank 25 is provided below the normally closed on-site discharge valve 24. The collection tank 25 is filled with neutralizing liquid to collect and process the on-site discharged liquid; the micro-negative pressure gauge 21, the second flow meter 22 and the three-way valve 23 are located downstream of the filter 2. The micro-negative pressure gauge 21 and the second flow meter 22 can be used to monitor in real time whether the system is working normally. The two connecting ports of the three-way valve 13 are connected to the leakage monitoring pipeline 1, and the other connecting port is connected to one end of the instrument calibration pipeline 26 for calibrating the gas detector; the other end of the instrument calibration pipeline 26 is connected to the calibration gas source. A fourth one-way valve 27 is further provided on the leakage monitoring pipeline 1 and is located downstream of the gas detector 3 .

[0025] When the reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system of this embodiment is used, one end of the leakage monitoring pipeline is connected to the leakage monitoring cavity 28, and the valves on the leakage monitoring pipeline 1, the valves on the power gas source pipeline 12, and the valves on the venting pipeline 9 are opened. Then, the venturi ejector 8 is opened, and the pressure regulating valve 14 is adjusted to make the readings of the first flow meter 15, the micro-negative pressure gauge 21, and the second flow meter 22 stable, and then the alarm threshold is set; the first one-way valve 6 is an air suction one-way valve. When there is no leakage in the variable volume clearance cavity, the system is under negative pressure, and the first one-way valve 6 is opened through the ejection effect of the power gas source. The air forms an internal and external circulation between the system and the atmosphere; when a leak occurs, the leaked gas enters the leakage monitoring pipeline 1 under the induced action of the power gas source, so that the air flow of the first one-way valve 6 entering the leakage detection pipeline is reduced or even the first one-way valve 6 is closed. The leaked gas is filtered, detected, diluted, and finally enters the vent pipeline 9. If the gas detector 3 detects that the content of the target gas exceeds the set threshold, the data is transmitted to the programmable controller 18 of the control cabinet in the form of an electrical signal, triggering the sound and light alarm to alarm, and at the same time transmitting the data to the human-machine interface 19 of the central control room so that the staff can take emergency measures in time.

Claims

1. A reciprocating compressor variable volume clearance chamber gas medium leakage monitoring system, comprising a leakage monitoring pipeline and a gas detector disposed on the leakage monitoring pipeline for analyzing the target gas content, wherein one end of the leakage monitoring pipeline is connected to the leakage monitoring cavity of the variable volume clearance chamber, and characterized in that: The other end of the leakage monitoring pipeline is connected to the negative pressure suction port of the negative pressure pump; the leakage monitoring pipeline is connected to a one-way suction structure for inhaling air; the one-way suction structure is arranged upstream of the gas detector.

2. The reciprocating compressor variable volume clearance chamber gas medium leakage monitoring system according to claim 1, characterized in that: It also includes a programmable controller, the gas detector is electrically connected to the programmable controller, and the programmable controller is equipped with an audible and visual alarm that issues an alarm when the content of the target gas in the leakage monitoring pipeline exceeds a set value.

3. The reciprocating compressor variable volume clearance chamber gas medium leakage monitoring system according to claim 2, characterized in that: The outlet of the negative pressure pump is connected to the venting structure.

4. The reciprocating compressor variable volume clearance chamber gas medium leakage monitoring system according to claim 3, characterized in that: The venting structure includes a venting pipeline and a target gas absorption device connected to the venting pipeline.

5. The reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system according to any one of claims 1 to 3, characterized in that: The negative pressure pump is a Venturi ejector; the inlet of the Venturi ejector is connected to the power gas source pipeline.

6. The reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system according to any one of claims 1 to 3, characterized in that: The one-way air suction structure is a one-way valve.

7. The reciprocating compressor variable volume clearance cavity gas medium leakage monitoring system according to any one of claims 1 to 3, characterized in that: A filter is provided on the leakage detection pipeline, and the filter is located upstream of the gas detector.

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