An improved process for the setting of an inlet buffer tank of a compressor unit

Abstract

The present invention discloses an improved process for setting an inlet buffer tank of a compressor unit, characterized in that: a mixing tank is provided at the inlet of the compressor unit, a by-pass buffer tank is provided after the cooler at the outlet of the compressor unit, the inlet of the by-pass buffer tank is connected after the cooler at the outlet of the compressor unit, the outlet of the by-pass buffer tank is connected to the mixing tank at the inlet of the compressor unit, and a regulating valve 1 is provided at the inlet of the by-pass buffer tank; when the pressure difference between the by-pass buffer tank and the inlet of the compressor unit is lower than 40% of the pressure difference between the inlet and outlet of the compressor unit, the regulating valve 1 is opened to send the gas at the outlet of the compressor unit into the buffer tank; the outlet of the by-pass buffer tank is connected to the mixing tank through a regulating valve 2. When the pressure in the mixing tank is lower than the designed pressure at the inlet of the compressor, the regulating valve 2 is opened to send the gas in the by-pass buffer tank into the mixing tank to keep the pressure in the mixing tank within the designed pressure range at the inlet of the compressor. Thus, when the flow rate of the external supply fluctuates, the compressor unit can output a stable flow rate, and at the same time, when the external supply flow rate is cut off, there is at least 6 to 18 minutes to ensure the safe shutdown of the system.

Description

Technical Field

[0001] The present invention relates to the fields of chemical engineering and energy conservation, and is an improved process for setting an inlet buffer tank of a compressor unit. Background Art

[0002] A gas holder is a common container device for storing and buffering gases. For a wet gas holder, there are problems such as large floor area, large water consumption, high humidity of stored gas, and equipment corrosion; while a dry gas holder, although solving problems such as water consumption and corrosion, also has problems such as large floor area, the sealing rubber is easily soiled by dust, and aging and leakage. In addition, China has relatively strict design and management requirements for gas holders, which results in high construction, use, and maintenance costs of gas holders. For small enterprises, the capital investment in setting up gas holders is large and the management difficulty is high. However, the buffer function of gas holders is urgently needed in the compression production process. Therefore, a compressor buffering method to replace the traditional gas holder is very necessary.

[0003] CN112610875 discloses a single-stage rubber-sealed membrane gas holder, including a base, a cabinet body, a gas transmission mechanism, an exhaust mechanism, a top cover, a guardrail, a ladder, and a gas leveling mechanism. The device provided by the present invention sets a cleaning component in the expansion mechanism. As the gas pushing component pulls the outer membrane to slide up and down, and at this time the cleaning component is relatively fixed, the oil scale accumulated on the inner wall of the outer membrane will be squeezed onto the guide plate through the scraping action of the scraper, and then through the slope of the guide plate itself, the oil scale will slide into the collection box for collection. The method for dealing with the situation where the paste-like contaminants affected by the surrounding environment of the gas holder adhere to the rubber sealing outer membrane can avoid the accumulation of paste-like contaminants on the rubber sealing outer membrane, prevent its accelerated aging, improve its service life, and can also reduce the self-weight of the rubber sealing outer membrane in real time, avoid the situation where it is difficult to unfold due to folding, and relatively reduce the resistance received when gas is input, making the movement of the piston smooth.

[0004] This method belongs to the traditional dry gas holder. Although it can reduce problems such as the aging of the sealing rubber and the hindrance of movement, for the buffering effect of the raw gas compression process, it is still realized by the traditional gas holder method, and there are still problems such as large floor area, high equipment investment, and complex design and maintenance.

[0005] CN114427523 discloses a reciprocating compressor exhaust buffer tank device, which relates to the technical field of compressors and includes a housing. At least two air chamber partitions are arranged inside the housing, and the air chamber partitions divide the interior of the housing into at least three air chambers. The housing is provided with the same number of air inlets as the number of air chamber partitions, and each air inlet is communicated with the interior of the corresponding air chamber. The housing is provided with an exhaust port communicated with the last air chamber. Each air inlet extends into the corresponding air chamber and is bent to form a 90° elbow, and the air outlet direction of the 90° elbow is opposite to the gas flow direction in the air chamber. At least two filter pipes are arranged inside the housing, and both ends of each filter pipe are in the shape of a bell mouth; by changing the gas flow direction, route and waveform, the suppression of air flow pulsation is achieved, and the safety and stability of the compressor unit are ensured.

[0006] CN 107429681 discloses a liquid-cooled compressor, which reduces the vibration of the piping and the noise from the device connected to the piping by means of a simple structure. The oil-cooled screw compressor (1) has a compressor main body (11), a liquid supply flow path (14), and a gas buffer part (20). The compressor main body (11) compresses gas. The liquid supply flow path (14) is communicated with a liquid supply hole (37), and the liquid supply hole (37) supplies a coolant into a gas compression space (33) formed in the compressor main body. The gas buffer part (20) has a gas accumulation part (28), and the gas accumulation part (28) accumulates gas that receives the pressure of the coolant flowing in the liquid supply flow path.

[0007] Although the above inventions can effectively buffer the pulsation of the compressor for gas, they cannot buffer the instability of the compressor outlet flow caused by the flow fluctuation of the gas source itself, and at the same time, they cannot provide enough emergency buffer time for the short-term interruption of the raw material gas supply or the influx of a large amount of raw material gas. Therefore, the present application makes the following inventions in view of the above problems. Summary of the Invention

[0008] An improved process for setting an inlet buffer tank of a compressor unit, characterized in that a mixing tank is provided at the inlet of the compressor unit, and the buffer volume of the mixing tank is 2-3% of the hourly flow rate under the inlet conditions of the compressor unit; a bypass buffer tank is provided after the cooler at the outlet of the compressor unit, and the buffer volume of the bypass buffer tank is 10-30% of the hourly flow rate under the outlet conditions of the compressor unit. The inlet of the buffer tank is connected after the cooler at the outlet of the compressor unit, the outlet of the bypass buffer tank is connected to the mixing tank at the inlet of the compressor unit, and a regulating valve 1 is provided at the inlet of the bypass buffer tank; when the pressure difference between the bypass buffer tank and the inlet of the compressor unit is lower than 40% of the pressure difference between the inlet and outlet of the compressor unit, the regulating valve 1 is opened to send the outlet gas of the compressor unit into the bypass buffer tank; the outlet of the bypass buffer tank is connected to the mixing tank through a regulating valve 2. When the pressure of the mixing tank is lower than the designed inlet pressure of the compressor, the regulating valve 2 is opened to send the gas in the bypass buffer tank into the mixing tank to keep the pressure of the mixing tank within the range of the designed inlet pressure of the compressor. Thus, when the external incoming flow rate fluctuates, the compressor unit can output a stable flow rate, and at the same time, when the external incoming flow rate is cut off, there is at least 6-18 minutes to ensure the safe shutdown of the system.

[0009] Preferably, when used to prevent a sudden decrease in the supply of raw material gas: when the raw material gas is supplied stably and normally under the designed conditions, when the pressure difference between the bypass buffer tank and the inlet of the compressor unit is higher than 70%-100% of the pressure difference between the inlet and outlet of the compressor unit, the regulating valve 1 is closed; when the pressure of the mixing tank is lower than 40-60% of the normal operating pressure, the regulating valve 2 is opened to send the high-pressure raw material gas in the bypass buffer tank to the mixing tank to supplement the gas volume at the inlet of the compressor unit, avoiding negative pressure at the inlet of the compressor unit caused by a decrease or sudden cut-off of the raw material gas, damaging the equipment, or causing air to leak into the inlet valve, affecting the quality of the raw material gas, or mixing with oxygen components to generate an explosion risk, and at the same time ensuring the stable flow rate of the compressed raw material gas.

[0010] Preferably, when used to prevent an excessive influx of raw material gas: when the raw material gas is supplied stably and normally under the designed conditions, when the pressure difference between the bypass buffer tank and the inlet of the compressor unit is higher than 40-50% of the pressure difference between the inlet and outlet of the compressor unit, the regulating valve 1 is closed; when the supply of the raw material gas suddenly increases and the pressure of the mixing tank exceeds 10-30% of the normal operating pressure, the regulating valve 1 is opened, and the opening degree of the regulating valve 1 is controlled by the outlet flow rate of the compressor unit, so that part of the compressed gas is sent into the bypass buffer tank to achieve the effect of stabilizing the main line flow rate.

[0011] Preferably, when it is necessary to stabilize the outlet flow of the compressor unit due to long-term fluctuations in the raw material gas source, both the regulating valve 1 and the regulating valve 2 are opened simultaneously. The opening of the regulating valve 2 is controlled by the pressure of the mixing tank, and the opening of the regulating valve 1 is interlocked and controlled by the pressure of the bypass buffer tank and the inlet and outlet flows of the compressor unit. The bypass buffer tank is continuously filled, and the pressure difference between the bypass buffer tank and the inlet of the compressor unit is maintained at 40-80% of the pressure difference between the inlet and outlet of the compressor unit. When the supply flow of the raw material gas is lower than the design condition, the opening of the regulating valve 2 is increased, and the high-pressure raw material gas in the bypass buffer tank is sent to the mixing tank to supplement the inlet gas volume of the compressor unit. When the supply of the raw material gas exceeds the designed gas volume, the opening of the regulating valve 1 is increased and the opening of the regulating valve 2 is decreased, so that more compressed raw material gas at the outlet of the compressor unit is sent into the bypass buffer tank to achieve the effect of stabilizing the main line flow.

[0012] Advantages of the present invention:

[0013] 1. The present invention replaces the gas holder to play a buffering role for the raw material gas and ensures the stability of the outlet flow of the compressor unit. Under extreme conditions, that is, when the raw material gas suddenly cuts off or the raw material gas doubles and surges in, a buffering time of 6-18 minutes can also be provided to wait for the raw material gas to return to normal, ensuring stable and continuous gas supply and avoiding direct shutdown.

[0014] 2. The equipment of the present invention has a much smaller floor area, lower construction cost and lower operation complexity than the gas holder. Moreover, because there is no need for water seal and rubber seal sliding device, the power consumption and water consumption are also greatly reduced, the leakage problem is avoided, and the buffering effect of the gas holder is basically achieved. It can be used as an affordable alternative to the gas holder for occasions where the area or safety distance does not meet the requirements for placing the gas holder and the gas holder cannot be installed, and can also greatly reduce the construction cost of enterprises. Specific embodiments

[0015] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0016] Example 1: A 10000 Nm 3 / h ammonia synthesis gas compression unit, the synthesis gas raw material gas is 0.3 MPa and needs to be compressed to 1.2 MPa. A mixing tank with a volume of 300 Nm 3 is set at the inlet of the compressor unit, and a bypass is set at the outlet of the compressor unit and sent to the bypass buffer tank. The gas volume of the bypass buffer tank is 2000 Nm 3A regulating valve 1 is installed on the bypass line from the outlet of the compressor unit to the bypass buffer tank. The opening of regulating valve 1 is controlled by the interlock of the pressure of the bypass buffer tank and the flow rate at the outlet of the compressor unit. The bypass buffer tank is connected to the mixing tank, and a regulating valve 2 is installed. The opening of regulating valve 2 is controlled by the pressure of the mixing tank.

[0017] When the raw material gas is supplied stably and normally under the design conditions, it is set that regulating valve 2 is closed after the pressure of the mixing tank reaches 0.3 MPa; it is set that regulating valve 2 is opened after the pressure of the bypass buffer tank is lower than 0.66 MPa or the flow rate at the outlet of the compressor unit is higher than 10500 Nm 3 / h, and regulating valve 2 is closed when the pressure of the bypass buffer tank reaches 1.1 MPa or the flow rate at the outlet of the compressor unit is lower than 9500 Nm 3 / h.

[0018] When the flow rate of the raw material gas suddenly drops to 5000 Nm 3 / h, regulating valve 2 is opened to send the high-pressure raw material gas in the bypass buffer tank to the mixing tank to supplement the gas volume at the inlet of the compressor unit to 0.3 MPa. A buffer time of 9 - 21 minutes can be provided to resume normal gas supply, to prevent the negative pressure at the inlet of the compressor unit caused by the reduction or sudden interruption of the raw material gas, which may damage the equipment, or to prevent air from leaking into the inlet valve, affecting the quality of the raw material gas and mixing with oxygen components to generate an explosion risk. At the same time, the flow rate of the compressed raw material gas can be ensured to be stable.

[0019] Example 2: An ammonia synthesis gas compression device with a capacity of 10000 Nm 3 / h in a certain plant area. The raw material gas of the synthesis gas is 0.3 MPa and needs to be compressed to 1.2 MPa. A mixing tank with a volume of 300 Nm 3 is installed at the inlet of the compressor unit. A bypass line is set at the outlet of the compressor unit and sent to the bypass buffer tank. The gas volume of the bypass buffer tank is 1200 Nm 3 ; A regulating valve 1 is installed on the bypass line from the outlet of the compressor unit to the bypass buffer tank. The opening of regulating valve 1 is controlled by the interlock of the pressure of the bypass buffer tank and the flow rate at the outlet of the compressor unit. The bypass buffer tank is connected to the mixing tank, and a regulating valve 2 is installed. The opening of regulating valve 2 is controlled by the pressure of the mixing tank.

[0020] When the raw material gas is supplied stably and normally under the design conditions, it is set that regulating valve 2 is closed after the pressure of the mixing tank reaches 0.3 MPa; it is set that regulating valve 2 is opened after the pressure of the bypass buffer tank is lower than 0.66 MPa or the flow rate at the outlet of the compressor unit is higher than 10500 Nm 3 / h, and regulating valve 2 is closed when the pressure of the bypass buffer tank reaches 0.75 MPa or the flow rate at the outlet of the compressor unit is lower than 9500 Nm 3 / h.

[0021] When the flow rate of the raw material gas is higher than 12000 Nm 3When the flow rate is [X] m³ / h, open the regulating valve 1 and control the opening degree of the regulating valve 1 through the outlet flow rate of the compressor unit, so that part of the compressed gas is sent into the bypass buffer tank until the bypass buffer tank is completely filled, so as to achieve the effect of stabilizing the main line flow rate. A buffer time of 18 - 21.6 minutes can be provided for restoring normal gas supply.

[0022] Example 3: A 10000 Nm³ / h ammonia synthesis gas compression unit in a certain plant area. The raw material gas of the synthesis gas is 0.3 MPa and needs to be compressed to 1.2 MPa. The mixing tank with a volume of 300 Nm³ is set at the inlet of the compressor unit. 3 / h ammonia synthesis gas compression unit, the raw material gas of the synthesis gas is 0.3 MPa and needs to be compressed to 1.2 MPa. The mixing tank with a volume of 300 Nm³ is set at the inlet of the compressor unit. 3 A bypass is set at the outlet of the compressor unit and sent into the bypass buffer tank. The gas volume of the bypass buffer tank is 2500 Nm³. 3 A regulating valve 1 is set on the bypass from the outlet of the compressor unit to the bypass buffer tank, and the opening degree of the regulating valve 1 is controlled by the interlock of the pressure of the bypass buffer tank and the inlet and outlet flow rates of the compressor unit; the bypass buffer tank is connected to the mixing tank, and a regulating valve 2 is set, and the opening degree of the regulating valve 2 is controlled by the pressure of the mixing tank.

[0023] When the raw material gas supplies gas stably and normally under the design conditions, it is set to close the regulating valve 2 after the pressure of the mixing tank reaches 0.3 MPa; it is set to open the regulating valve 2 when the pressure of the bypass buffer tank is lower than 0.7 MPa or the outlet flow rate of the compressor unit is higher than 10500 Nm³ / h, and close the regulating valve 2 when the pressure of the bypass buffer tank reaches 1.0 MPa or the outlet flow rate of the compressor unit is lower than 9500 Nm³ / h. 3 / h, and close the regulating valve 2 when the pressure of the bypass buffer tank reaches 1.0 MPa or the outlet flow rate of the compressor unit is lower than 9500 Nm³ / h. 3 / h.

[0024] When the flow rate of the fed raw material gas fluctuates greatly, open the regulating valve 1 and the regulating valve 2 at the same time. Control the opening degree of the regulating valve 2 through the pressure of the mixing tank; control the opening degree of the regulating valve 1 through the interlock of the pressure of the bypass buffer tank and the inlet and outlet flow rates of the compressor unit, so that the bypass buffer tank is continuously filled and the pressure is always maintained at 0.7 - 1.0 MPa. When the supply flow rate of the raw material gas is lower than 9500 Nm³ / h, increase the opening degree of the regulating valve 2, and send the high-pressure raw material gas in the bypass buffer tank to the mixing tank to supplement the gas volume at the inlet of the compressor unit; when the supply of the raw material gas exceeds 10500 Nm³ / h, increase the opening degree of the regulating valve 1 and decrease the opening degree of the regulating valve 2, so that more compressed gas is sent into the bypass buffer tank to achieve the effect of continuously and stably maintaining the main line flow rate for a long time. 3 / h, increase the opening degree of the regulating valve 2, and send the high-pressure raw material gas in the bypass buffer tank to the mixing tank to supplement the gas volume at the inlet of the compressor unit; when the supply of the raw material gas exceeds 10500 Nm³ / h 3 / h, increase the opening degree of the regulating valve 1 and decrease the opening degree of the regulating valve 2, so that more compressed gas is sent into the bypass buffer tank to achieve the effect of continuously and stably maintaining the main line flow rate for a long time.

Claims

1. A method for buffering the gas of a compressor unit, characterized in that A mixing tank is set at the inlet of the compressor unit. The buffer volume of the mixing tank is 2 - 3% of the hourly flow rate at the inlet state of the compressor unit. A bypass buffer tank is set after the cooler at the outlet of the compressor unit. The buffer volume of the bypass buffer tank is 10 - 30% of the hourly flow rate at the outlet state of the compressor unit. The inlet of the bypass buffer tank is connected after the cooler at the outlet of the compressor unit, and the outlet of the bypass buffer tank is connected to the mixing tank at the inlet of the compressor unit. A regulating valve 1 is set at the inlet of the bypass buffer tank; when the pressure difference between the bypass buffer tank and the inlet of the compressor unit is lower than 40% of the pressure difference between the inlet and outlet of the compressor unit, open the regulating valve 1 to send the gas at the outlet of the compressor unit into the buffer tank; the outlet of the bypass buffer tank is connected to the mixing tank through a regulating valve 2. When the pressure of the mixing tank is lower than the designed inlet pressure of the compressor, open the regulating valve 2 to send the gas in the bypass buffer tank into the mixing tank to keep the pressure of the mixing tank within the designed inlet pressure range of the compressor, thereby achieving stable flow output of the compressor unit when the flow rate of the raw material gas fed from the outside fluctuates or there is a short-term supply interruption.