Automatic adjusting method for inlet guide vane of oxygen compressor

Abstract

The invention belongs to the technical field of steel mill oxygen supply, and particularly relates to an automatic adjusting method for an inlet guide vane of an oxygen compressor. Comprising the following steps: (1) air supply adjustment: taking oxygen output flow Q of each air supply system as a tracking object, respectively setting control parameters B and F of a grid-connected valve and an emptying valve in each air supply system, taking B as a target value to adjust the opening degree of the grid-connected valve, enabling Q to approach B, and taking B-F as a threshold value to control opening and closing of the emptying valve; and (2) gas consumption regulation: respectively setting control parameters D and H of a guide vane valve and a return valve of each compressor user by taking the inlet oxygen pressure P of each compressor user as a tracking object, and regulating the opening degree of the guide vane valve by taking P as a target value. The oxygen supply end and the oxygen demand end are timely, accurately and in-place regulated and controlled through the flow and the pressure respectively, an emptying valve and a grid-connected valve of the air supply system are automatically controlled, the abnormal change of the oxygen yield caused by the fluctuation of the oxygen consumption is prevented, and the stability of oxygen production and use is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of oxygen supply in steel plants, and in particular relates to an automatic adjustment method for an inlet guide vane of an oxygen compressor. Background Art

[0002] As steel mills continue to carry out technical research on energy conservation and consumption reduction, the application of pre-machine oxygen enrichment technology has made the external supply process of oxygen products more diversified. The oxygen produced by the air separation unit in the steel plant's external compression process has a room temperature and a pressure of 10-20kpa. The current users are compressor users and pre-machine oxygen enrichment users. After entering the oxygen compressor user, the pressure is further increased to about 2.5MPa or 0.8MPa to supply oxygen medium to steelmaking and ironmaking users respectively, that is, the compressor users are further divided into medium-pressure users and low-pressure users according to the oxygen pressure. Among them, the oxygen compressor inlet guide vane valve is the key valve to control the gas supply flow and the main valve for compressor load adjustment. It needs to be adjusted according to the production load of the air separation unit.

[0003] At present, the whole oxygen supply system of the steel plant has the following deficiencies during use: the oxygen-enriched users in front of the machine are not stable during the oxygen use process, and the amount of oxygen used will suddenly increase or decrease sharply, which causes the instability of the gas supply network, and the oxygen turbine compressor needs to maintain a certain pressure, otherwise there will be "surge" phenomenon, threatening the equipment and personal safety. For this reason, the return valve is manually opened to put the compressor in a small amount of cycle compression state to avoid the abnormal "surge" condition of the unit. The fluctuation of oxygen consumption also affects the gas supply system, and there will be insufficient oxygen supply or waste of oxygen release. For this reason, the vent valve needs to be manually adjusted, otherwise it will cause abnormal changes in oxygen production, destroy the balance of oxygen supply materials, and reduce the purity of the product. The vent valve and the reflux valve cannot be regulated in a timely, accurate, and appropriate manner through manual control, which takes up a lot of personnel energy. Once misoperated, it will affect the production organization of the steel plant. Summary of the invention

[0004] The object of the present invention is to provide an automatic adjustment method for an inlet guide vane of an oxygen compressor to solve the problems existing in the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is: an automatic adjustment method for the inlet guide vanes of an oxygen compressor, comprising the following steps:

[0006] (1) Gas supply regulation: The oxygen output flow rate Q of each gas supply system is tracked, and the control parameters B and F of the grid-connected valve and the vent valve in each gas supply system are set respectively. B is used as the target value to adjust the opening of the grid-connected valve so that Q approaches B, and BF is used as the threshold value to control the opening and closing of the vent valve;

[0007] (2) Gas regulation: Taking the inlet oxygen pressure P of each compressor user as the tracking object, the control parameters D and H of the guide vane valve and the reflux valve of each compressor user are set respectively. Using P as the target value to adjust the opening of the guide vane valve to make P approach D, and using D - H as the threshold to control the opening and closing of the reflux valve.

[0008] Furthermore, the gas supply system includes an air separation unit, a vent valve, a grid connection valve, and a flow meter. The air separation unit is sequentially connected to the grid connection valve and the flow meter through a gas supply pipeline. A vent valve is connected in parallel on the gas supply pipeline between the air separation unit and the grid connection valve. The oxygen output flow Q is the instantaneous oxygen flow at the output end of the gas supply system measured by the flow meter.

[0009] Furthermore, the compressor user includes a pressure gauge, a guide vane valve, an oxygen compressor, and a reflux valve. The pressure gauge is sequentially connected to the guide vane valve and the turbine compressor through a gas-using pipeline. The guide vane valve and the turbine compressor are jointly connected in parallel with the reflux valve. One end of the flow meter of the gas supply system and one end of the pressure gauge of the compressor user are both connected to the oxygen pipeline network. The inlet oxygen pressure P is the instantaneous oxygen pressure at the input end of the compressor user detected by the pressure gauge.

[0010] Furthermore, the specific method of gas supply regulation is as follows:

[0011] When Q > B, the grid connection valve is adjusted to a smaller opening;

[0012] When Q < B, the grid connection valve is adjusted to a larger opening;

[0013] When Q = B, the opening of the grid connection valve remains unchanged;

[0014] When Q ≥ B - F, the vent valve opens;

[0015] When Q < B - F, the vent valve closes.

[0016] Furthermore, the specific method of gas-using regulation is as follows:

[0017] When P > D, the guide vane valve is adjusted to a larger opening;

[0018] When P < D, the guide vane valve is adjusted to a smaller opening;

[0019] When P = D, the opening of the guide vane valve remains unchanged;

[0020] When P ≥ D - H, the reflux valve closes;

[0021] When P < D - H, the reflux valve opens.

[0022] The present invention has the following beneficial effects:

[0023] 1. The present invention automatically controls the vent valve and grid-connected valve of the gas supply system through flow rate, thereby preventing abnormal changes in oxygen production caused by fluctuations in oxygen consumption, avoiding damage to the oxygen supply material balance and reduction in product purity, thereby enabling the air separation unit to operate stably.

[0024] 2. The present invention automatically controls the guide vane valve and return valve of the compressor user through pressure to prevent the instability of the gas supply network caused by a sudden increase or decrease in oxygen consumption, thereby avoiding the "surge" phenomenon of the oxygen compressor.

[0025] 3. Automatic control replaces manual control, and can timely, accurately and appropriately adjust the oxygen consumption when it changes, without occupying too much energy of the staff and reducing misoperation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the structure of the present invention.

[0027] Among them: 1. Gas supply system; 2. Air separation unit; 3. Vent valve; 4. Grid connection valve; 5. Flow meter; 6. Gas supply pipeline; 7. Compressor user; 8. Pressure gauge; 9. Guide vane valve; 10. Oxygen compressor; 11. Return valve; 12. Gas pipeline; 13. Oxygen pipeline network; 14. Pre-machine oxygen enrichment user. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and drawings.

[0029] Embodiment 1: This embodiment provides a method for automatically adjusting the inlet guide vanes of an oxygen compressor 10, especially a method for the air supply adjustment step.

[0030] like Figure 1 As shown, oxygen is produced through two sets of gas supply systems 1, the gas supply system 1 includes an air separation unit 2, a vent valve 3, a grid valve 4, and a flow meter 5. The air separation unit 2 is connected to the grid valve 4 and the flow meter 5 in sequence through a gas supply pipeline 6. The vent valve 3 is connected in parallel on the gas supply pipeline 6 between the air separation unit and the grid valve 4. The oxygen output flow rate Q is the instantaneous flow rate of oxygen at the output end of the gas supply system 1 measured by the flow meter 5.

[0031] There are two sets of compressor users 7, and the compressor user 7 includes a pressure gauge 8, a guide vane valve 9, an oxygen compressor 10, and a reflux valve 11. The pressure gauge 8 is connected to the guide vane valve 9 and the turbine compressor in sequence through a gas pipeline 12. The guide vane valve 9 and the turbine compressor are connected in parallel with the reflux valve 11. One end of the flowmeter 5 of the gas supply system 1 and one end of the pressure gauge 8 of the compressor user 7 are both connected to the oxygen pipeline network 13. The inlet oxygen pressure P is the instantaneous oxygen pressure at the input end of the compressor user 7 detected by the pressure gauge 8. The oxygen-rich user 14 in front of the machine is connected to the oxygen pipeline network 13.

[0032] Install a flowmeter 5 at the output end of each gas supply system 1 to detect the oxygen output flow Q. Install a PID control module on the grid connection valve 4 and the vent valve 3, and set the control parameter B of the grid connection valve 4. Taking the oxygen output flow Q as the tracking object, compare Q and B, and control the opening degree of the grid connection valve 4 to make Q approach B; set the control parameter F of the vent valve 3. The vent valve 3 takes the control parameter B of the grid connection valve 4 and the oxygen output flow Q as the tracking object. The vent valve 3 first automatically collects the current control parameter B, performs the logical operation B - F, and then compares the operation result with Q as the threshold to control the opening and closing of the vent valve 3.

[0033] The control parameters B and F are determined according to the actual production needs. In this embodiment, there are two sets of gas supply systems 1, and the maximum output of each set is 10000 m 3 / h. During normal production, the total oxygen demand is 18000 m 3 / h. That is to say, the flow output of each gas supply system 1 is 9000 m 3 / h. Set B = 9000 m 3 / h, F = 500 m 3 / h. During normal production, the grid connection valve 4 and the vent valve 3 maintain a certain opening degree to make Q = B. At this time, the supply and demand of oxygen reach balance;

[0034] When the oxygen demand increases (for example, the oxygen-rich user 14 in front of the machine needs to supply 1200 m 3 / h of oxygen), change the parameter B to 9600 m 3 / h. At this time, Q < B, and the grid connection valve 4 is adjusted to a larger opening until Q = B. During this process, at the beginning, Q = 9000 m 3 / h < 9600 - 500 m 3 / h. Therefore, the vent valve 3 is closed. When Q continues to increase to 9100 m 3 / h, it approaches the target value of 9600 m 3 / h, and the vent valve 3 opens to prevent the air separation machine from being blocked due to a rapid increase in Q;

[0035] When the oxygen demand decreases (for example, the oxygen supply demand of the oxygen-rich user 14 in front of the machine decreases by 1200 m 3 / h), change parameter B to 9000 m 3 / h. At this time, Q > B, and the grid connection valve 4 is adjusted to a smaller opening until Q = B. During this process, initially Q = 9600 m 3 / h > 9000 - 500 m 3 / h. Therefore, the vent valve 3 is opened. When an abnormal situation occurs and the oxygen production decreases abnormally, in order to prevent waste of oxygen product discharge, Q continues to decrease to below 8500 m 3 / h, and then the vent valve 3 is closed.

[0036] It should be noted that the adjustment of the opening degrees of the grid connection valve 4 and the vent valve 3 is a prior art. The specific principle is as follows: taking the grid connection valve 4 as an example, when the grid connection valve 4 executes the opening action, it does not open fully at once, but opens 10% each time (the specific amount of opening each time can be set by oneself), and thus gradually opens. That is, it first opens 10%, and then compares Q and B. If Q < B, the grid connection valve 4 continues to open 10% until Q = B. Similarly, the opening and closing of the vent valve 3 is also a process of gradually opening or closing.

[0037] Embodiment 2: This embodiment provides a method for automatically adjusting the inlet guide vane of an oxygen compressor 10, especially a method for the gas usage adjustment step. The connection structure of the gas supply system 1, the compressor user 7, and the pre-compressor oxygen-rich user 14 in this embodiment is the same as that in Embodiment 1.

[0038] Install a pressure gauge 8 at the input end of each compressor user 7 to detect the inlet oxygen pressure P. Set the control parameters D of the guide vane valve 9 and the reflux valve 11. Taking the inlet oxygen pressure P as the tracking object, compare D and P, and control the opening degree of the guide vane valve 9 to make P approach D; set the control parameter H of the reflux valve 11. The reflux valve 11 takes the control parameter D of the guide vane valve 9 and the oxygen output flow P as the tracking objects. The reflux valve 11 first automatically collects the current control parameter D, performs the logical operation D - H, and then compares the operation result with P as a threshold to control the opening and closing of the reflux valve 11.

[0039] The control parameters D and H are determined according to actual production needs. In this embodiment, the inlet pressure requirement of the compressor user 7 is 15 KPa. Set the parameter D to 15 KPa and H to 7 KPa. During normal production, the reflux valve 11 is closed, and the guide vane valve 9 automatically adjusts the opening degree to make P = D. When the oxygen demand of the pre-compressor oxygen-rich user 14 increases, resulting in P dropping to 13 KPa, the PID control module of the guide vane valve 9 compares D and P. Since P < D, the guide vane valve 9 adopts a control strategy of gradually closing to reduce the intake of the oxygen compressor 10. At this time, the pipeline network pressure will rise. When it rises to 15 kPa, the inlet guide vane valve 9 stops operating;

[0040] The oxygen demand of the oxygen-enriched user 14 in front of the machine decreases, causing P to rise to 17KPa. The PID control module of the guide vane valve 9 compares D and P. P>D, and the guide vane valve 9 adopts a control strategy of gradually opening to increase the suction volume of the oxygen compressor 10. At this time, the pipeline network pressure will drop. When it drops to 15kpa, the inlet guide vane valve 9 stops operating.

[0041] The function of the return valve 11 is mainly to provide security. The control threshold of the return valve 11 is 15-7KPa=8KPa. The control process of the guide vane valve 9 is relatively slow. If the pipe network pressure changes suddenly and the guide vane valve 9 fails to adjust in place, it will affect the inlet pressure of the oxygen compressor 10, resulting in the suction pressure of the oxygen compressor 10 being too low during operation, causing the danger of "surge". When the suction port pressure of the oxygen compressor 10 drops excessively to 8kpa, the return valve 11 automatically controls the PID module to automatically intervene. Through the comparison operation of the module, the return valve 11 automatically opens gradually. At this time, the high-pressure oxygen in the compressor outlet pipe passes through the throttling of the return valve 11 and returns to the suction port of the compressor to meet the safe suction volume of the compressor.

[0042] It should be noted that the control principles of the guide vane valve 9 and the return valve 11 are substantially the same as those of the grid-connected valve 4 .

[0043] The above-described embodiments are merely descriptions of preferred implementations of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made by ordinary persons in the art to the technical solution of the present invention should all fall within the scope of protection of the present invention.

[0044] The techniques, shapes, and structural parts not described in detail in the present invention are all well-known techniques.

Claims

1. A method for automatically adjusting the inlet guide vanes of an oxygen compressor, characterized in that: It includes the following steps: (1) Air supply regulation: Taking the oxygen output flow rate Q of each air supply system as the tracking object, respectively set the control parameters B and F of the grid connection valve and the vent valve in each air supply system. Use B as the target value to adjust the opening of the grid connection valve to make Q approach B, and use B - F as the threshold to control the opening and closing of the vent valve; (2) Gas consumption regulation: Taking the inlet oxygen pressure P of each compressor user as the tracking object, respectively set the control parameters D and H of the guide vane valve and the reflux valve of each compressor user. Use P as the target value to adjust the opening of the guide vane valve to make P approach D, and use D - H as the threshold to control the opening and closing of the reflux valve.

2. The oxygen compressor inlet guide vane automatic adjustment method according to claim 1, characterized in that: The air supply system includes an air separation unit, a vent valve, a grid connection valve, and a flow meter. The air separation unit is sequentially connected to the grid connection valve and the flow meter through an air supply pipeline. A vent valve is connected in parallel on the air supply pipeline between the air separation unit and the grid connection valve. The oxygen output flow rate Q is the instantaneous oxygen flow rate at the output end of the air supply system measured by the flow meter.

3. The oxygen compressor inlet guide vane automatic adjustment method according to claim 2, characterized in that: The compressor user includes a pressure gauge, a guide vane valve, an oxygen compressor, and a reflux valve. The pressure gauge is sequentially connected to the guide vane valve and the turbine compressor through a gas consumption pipeline. The guide vane valve and the turbine compressor are jointly connected in parallel with the reflux valve. One end of the flow meter of the air supply system and one end of the pressure gauge of the compressor user are both connected to the oxygen pipeline network. The inlet oxygen pressure P is the instantaneous oxygen pressure at the input end of the compressor user detected by the pressure gauge.

4. The oxygen compressor inlet guide vane automatic adjustment method according to claim 3, characterized in that: The specific method of the air supply regulation is as follows: When Q > B, the grid connection valve is adjusted to a smaller opening; When Q < B, the grid connection valve is adjusted to a larger opening; When Q = B, the opening of the grid connection valve remains unchanged; When Q ≥ B - F, the vent valve opens; When Q < B - F, the vent valve closes.

5. The oxygen compressor inlet guide vane automatic adjustment method according to claim 4, characterized in that: The specific method of the gas consumption regulation is as follows: When P > D, the guide vane valve is adjusted to a larger opening; When P < D, the guide vane valve is adjusted to a smaller opening; When P = D, the opening of the guide vane valve remains unchanged; When P ≥ D - H, the reflux valve closes; When P < D - H, the reflux valve opens.

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