A full-process automatic control method for a gas system

Abstract

The present invention discloses a method for automatic control of the entire process of a gas system. The gas system includes the following parts: blast furnace gas and coke oven gas are mixed through a gas mixing station; the mixed gas is pressurized by a gas compressor; the pressurized mixed gas is purified by a gas purification system; the purified mixed gas enters a gas cabinet for storage and is delivered to a heat treatment furnace for use in real time. On the basis of realizing automatic gas mixing and automatic "gas cabinet-blower", the process flow of the system is opened up, and by decomposing the specific valve operations of the entire process of "gas mixing-gas pressurization-gas purification-gas storage and distribution", the relevant valve actions are added to the automatic operation model, and the valve actions of the entire system are guided by key indicators, ultimately achieving automatic control of the entire system. "Zero" operation of the gas system is achieved, the stability and safety of the system are improved, the efficiency of post personnel is greatly improved, and the manual participation time of the system is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal gas mixing, and in particular relates to a full-process automatic control method for a coal gas system. Background Art

[0002] Under the background of promoting smart energy, the applicant has also made great breakthroughs in the intelligent centralized control of the gas system, and successfully realized regional unmanned operation and intelligent centralized control in September 2022. It is of great significance to realize the automatic control of each gas area of ​​the gas plant. Therefore, the technical personnel of the gas plant continue to tackle the problems of the automated operation of the gas system, and convert manual operations into computer voice for automated and intelligent operations.

[0003] On the other hand, according to the applicant's overall plan for plate production, to maximize the output and benefits of heat-treated plate, medium plate heat-treatment furnaces place higher demands on the calorific value of the mixed gas used. To ensure the stability of the calorific value of the mixed gas used in medium plate heat treatment, the gas plant needs to automate the operation of the gas system supporting the heat-treatment furnace to achieve a stable supply of mixed gas calorific value. Summary of the Invention

[0004] Purpose of the invention: The purpose of the present invention is to disclose a full-process automatic control method for a gas system.

[0005] Technical solution: The present invention discloses a method for automatic control of the entire process of a gas system, wherein the gas system comprises the following parts:

[0006] In the first part, blast furnace gas and coke oven gas are mixed through a gas mixing station;

[0007] The second part is to increase the pressure of the mixed gas through a gas compressor;

[0008] In the third part, the pressurized mixed gas is purified by the gas purification system;

[0009] In the fourth part, the purified mixed gas enters the gas tank for storage and is delivered to the heat treatment furnace for use in real time;

[0010] The full-process automatic control method includes:

[0011] In the first part, the gas mixing station is composed of a blast furnace gas pipeline and a coke oven gas pipeline merged into a mixed gas pipeline, a blast furnace gas pressure regulating butterfly valve and a blast furnace gas flow regulating butterfly valve are provided on the blast furnace gas pipeline, and a coke oven gas flow regulating butterfly valve is provided on the coke oven gas pipeline. The blast furnace gas pressure regulating butterfly valve is used to regulate the mixed gas pressure to maintain it at a target value, so that the mixed gas pressure is stable and does not cause negative pressure. The calorific value of the mixed gas is controlled by the blast furnace gas flow regulating butterfly valve and the coke oven gas flow regulating butterfly valve to ensure that the flow is automatically proportioned according to the set calorific value;

[0012] In the second part, the saturation pressure value is determined based on the gas tank capacity, and the automatic control logic of the gas compressor is adjusted: when the gas tank capacity reaches a high level, the gas compressor automatically sets the outlet pressure to a value lower than the saturation pressure value and stops supplying gas to the gas tank. When the gas tank capacity drops to a low level, the gas compressor automatically sets the outlet pressure to a value higher than the saturation pressure value and starts supplying gas to the gas tank.

[0013] In the third part, an inlet valve and a bypass valve are set between the gas compressor and the gas purification system. The inlet valve is connected to the gas purification system. When the gas compressor delivers gas to the gas tank, the inlet valve is opened and the bypass valve is closed. When the gas compressor stops delivering gas to the gas tank, the bypass valve is opened and the inlet valve is closed to ensure the stability of the calorific value of the mixed gas.

[0014] In the fourth part, the gas that has been mixed, pressurized, and purified enters the gas tank intermittently through the automatic frequency conversion setting of the gas compressor. The gas tank triggers the closing and opening of the gas tank inlet valve according to the upper and lower limits of the gas tank capacity, thereby realizing automatic control of the gas tank.

[0015] Furthermore, in the first part, the blast furnace gas flow rate and the coke oven gas flow rate are set according to the following:

[0016] Blast furnace gas flow rate = [(coke oven gas calorific value - high coke mixed gas calorific value) / (coke oven gas calorific value - blast furnace gas calorific value)] × high coke mixed gas volume;

[0017] Coke oven gas flow rate = [(calorific value of high-coke mixed gas - calorific value of blast furnace gas) / (calorific value of coke oven gas - calorific value of blast furnace gas)] × high-coke mixed gas volume.

[0018] Furthermore, in the second part, when the outlet pressure of the gas compressor is set to be greater than the saturation pressure value, the blast furnace gas flow regulating butterfly valve is automatically opened and automatic mixing adjustment begins; when the outlet pressure of the gas compressor is set to be less than the saturation pressure value, the blast furnace gas flow regulating butterfly valve is automatically closed and mixing adjustment stops.

[0019] Furthermore, in the second part, the gas tank adopts 20,000m 3 The saturated pressure value of the gas tank is 12kPa. When the gas tank capacity reaches a high level, the gas compressor automatically sets the outlet pressure to 11kPa. When the gas tank capacity drops to a low level, the gas compressor automatically sets the outlet pressure to 13kPa.

[0020] Furthermore, in the third part, the bypass valve is connected to the regeneration system.

[0021] Furthermore, in the third part, the coal gas purification system includes a desulfurization tower and a naphthalene removal tower.

[0022] Beneficial effects: Compared with the prior art, the present invention:

[0023] 1. Achieve "zero" operation of the gas system, improve the stability and safety of the system, greatly improve the efficiency of post personnel, and significantly reduce the manual participation time of the system;

[0024] 2. After the system achieved fully automated control, the calorific value of the mixed gas was significantly reduced from the previous fluctuation range of 1600-3200 kcal to within ±100 of the target calorific value. Furthermore, the combustion efficiency of the heat treatment furnace has increased by over 90% (steel processing time has been reduced from 8.5 minutes to less than 5.5 minutes), improving energy efficiency while increasing steel production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the automatic control of the gas system of the present invention;

[0026] Figure 2 Schematic diagram of the gas system flow of the present invention. Implementation Method

[0027] The present invention will be further described below with reference to the embodiments.

[0028] like Figure 1 The full-process automatic control method of the gas system shown in FIG.

[0029] The gas system includes Figure 2 The following sections are shown:

[0030] In the first part, blast furnace gas and coke oven gas are mixed through a gas mixing station; the gas mixing station is composed of a blast furnace gas pipeline and a coke oven gas pipeline merged into a mixed gas pipeline, a blast furnace gas pressure regulating butterfly valve and a blast furnace gas flow regulating butterfly valve are provided on the blast furnace gas pipeline, and a coke oven gas flow regulating butterfly valve is provided on the coke oven gas pipeline. The blast furnace gas pressure regulating butterfly valve is used to regulate the pressure of the mixed gas to maintain it at a target value, so that the pressure of the mixed gas is stable and does not cause negative pressure. The calorific value of the mixed gas is controlled by the blast furnace gas flow regulating butterfly valve and the coke oven gas flow regulating butterfly valve to ensure that the flow is automatically proportioned according to the set calorific value;

[0031] The blast furnace gas flow rate and coke oven gas flow rate are set according to the following:

[0032] Blast furnace gas flow rate = [(coke oven gas calorific value - high coke mixed gas calorific value) / (coke oven gas calorific value - blast furnace gas calorific value)] × high coke mixed gas volume;

[0033] Coke oven gas flow rate = [(calorific value of high-coke mixed gas - calorific value of blast furnace gas) / (calorific value of coke oven gas - calorific value of blast furnace gas)] × high-coke mixed gas volume.

[0034] The second part is to increase the pressure of the mixed gas through a gas compressor (centrifugal fan);

[0035] The saturation pressure value is determined based on the gas tank capacity, and the automatic control logic of the gas compressor is adjusted: when the gas tank capacity reaches a high level, the gas compressor automatically sets the outlet pressure to a value lower than the saturation pressure value and stops supplying gas to the gas tank. When the gas tank capacity drops to a low level, the gas compressor automatically sets the outlet pressure to a value higher than the saturation pressure value and starts supplying gas to the gas tank.

[0036] When the outlet pressure of the gas compressor is set to be greater than the saturation pressure value, the blast furnace gas flow regulating butterfly valve is automatically opened and automatic mixing adjustment begins; when the outlet pressure of the gas compressor is set to be less than the saturation pressure value, the blast furnace gas flow regulating butterfly valve is automatically closed and mixing adjustment stops.

[0037] The gas tank adopts 20,000m 3 The saturation pressure of a gas tank is 12kPa. When the inlet pressure exceeds 12kPa, the tank is storing gas. When the inlet pressure drops below 12kPa, the tank stops storing gas (consistently providing a stable supply of gas to users). Therefore, the system's automatic control logic is that when the tank reaches a high capacity, the gas compressor automatically sets the outlet pressure to 11kPa, stopping gas supply to the tank and maintaining a low flow rate for the regeneration system. When the tank reaches a low capacity, the gas compressor automatically sets the outlet pressure to 13kPa and begins supplying gas to the tank.

[0038] In the third part, the pressurized mixed gas is purified by a gas purification system, which includes a desulfurization tower and a naphthalene removal tower;

[0039] An inlet valve and a bypass valve are provided between the gas compressor and the gas purification system, wherein the inlet valve is connected to the gas purification system, and the bypass valve is connected to the regeneration system.

[0040] When the gas compressor supplies gas to the gas tank, the inlet valve is opened and the bypass valve is closed at the same time, so that the mixed gas with stable calorific value passes through the purification system and is sent to the gas tank; when the gas compressor stops supplying gas to the gas tank, the bypass valve is opened and the inlet valve is closed at the same time, so that the small flow of blast furnace gas with unstable calorific value goes to the regeneration system through the bypass pipeline. The automatic valve setting this time can effectively ensure the stability of the calorific value of the mixed gas.

[0041] In the fourth part, the purified mixed gas enters the gas tank for storage and is delivered to the heat treatment furnace for use in real time;

[0042] The gas after gas mixing, pressurization and purification is intermittently fed into the gas tank through the automatic frequency conversion setting of the gas compressor. The gas tank triggers the closing and opening of the inlet valve of the gas tank according to the upper and lower limits of the gas tank capacity, thereby realizing automatic control of the gas tank.

[0043] In this embodiment, by realizing the automatic control of the above units and finally connecting them in series through the control idea of ​​the whole process, the automatic control of the whole system can be realized.

[0044] (1) When the outlet pressure of the gas compressor is set to >12kPa, the blast furnace gas flow regulating butterfly valve will automatically open and start automatic mixing adjustment; when the outlet pressure of the gas compressor is set to <12kPa, the blast furnace gas flow regulating butterfly valve will automatically close and stop mixing adjustment;

[0045] (2) When the outlet pressure of the gas compressor is greater than 12kPa, the bypass valve of the purification system is automatically closed, and the gas starts to be purified and sent to the gas tank; when the outlet pressure of the gas compressor is less than 12kPa, the bypass valve of the purification system is automatically opened and the inlet valve of the purification system is closed, and the gas stops being purified and sent to the regeneration system;

[0046] (3) When the gas tank capacity reaches the upper limit, a signal to stop the gas tank from upgrading is automatically sent to the centrifugal fan, and the fan automatically reduces the frequency to the outlet pressure of 11kPa; when the gas tank capacity drops to the lower limit, a signal to start the gas tank from upgrading is automatically sent to the centrifugal fan, and the fan automatically increases the frequency to the outlet pressure of 13kPa.

[0047] The implementation of this control method first requires checking and ensuring that the centrifugal fan frequency conversion device and pressure instrument system have reliable interlocking functions; and checking and debugging the valves of the gas mixing system, purification system, and storage system to meet the remote automation requirements.

[0048] First, based on the calorific value requirements of the medium plate heat treatment furnace for the mixed gas (2200-3000 kcal / m³), the gas plant first inspected the valve electric devices of the gas mixing station to ensure that the valve electric devices fully matched the PLC program. The model was then established based on the actual situation of intermittent cabinet upgrades of 20,000 cabinets.

[0049] Secondly, on the basis of realizing the automatic proportioning operation of the mixing station, the upgrading requirement of the 20,000 gas tank is linked with the automatic variable load setting of the gas compressor. The upper and lower limits of the gas tank capacity are used to trigger the gas compressor station to change the pressure setting, thereby realizing the automatic interlocking function of "gas tank and gas compressor".

[0050] Finally, on the basis of realizing automatic gas mixing and "gas cabinet-blower" automation, the process flow of the system is opened up. By decomposing the specific valve operations of the entire process of "gas mixing-gas pressurization-gas purification-gas storage and distribution", the relevant valve actions are added to the automatic operation model, and key indicators are used to guide the valve actions of the entire system, ultimately achieving automatic control of the entire system.

Claims

1. A method for automatic control of the entire process of a gas system, characterized by: The gas system includes the following parts: In the first part, blast furnace gas and coke oven gas are mixed through a gas mixing station; The second part is to increase the pressure of the mixed gas through a gas compressor; In the third part, the pressurized mixed gas is purified by the gas purification system; In the fourth part, the purified mixed gas enters the gas tank for storage and is delivered to the heat treatment furnace for use in real time; The full-process automatic control method includes: In the first part, the gas mixing station is composed of a blast furnace gas pipeline and a coke oven gas pipeline merged into a mixed gas pipeline, a blast furnace gas pressure regulating butterfly valve and a blast furnace gas flow regulating butterfly valve are provided on the blast furnace gas pipeline, and a coke oven gas flow regulating butterfly valve is provided on the coke oven gas pipeline. The blast furnace gas pressure regulating butterfly valve is used to regulate the mixed gas pressure to maintain it at a target value, so that the mixed gas pressure is stable and does not cause negative pressure. The calorific value of the mixed gas is controlled by the blast furnace gas flow regulating butterfly valve and the coke oven gas flow regulating butterfly valve to ensure that the flow is automatically proportioned according to the set calorific value; In the second part, the saturation pressure value is determined based on the gas tank capacity, and the automatic control logic of the gas compressor is adjusted: when the gas tank capacity reaches a high level, the gas compressor automatically sets the outlet pressure to a value lower than the saturation pressure value and stops supplying gas to the gas tank. When the gas tank capacity drops to a low level, the gas compressor automatically sets the outlet pressure to a value higher than the saturation pressure value and starts supplying gas to the gas tank. In the third part, an inlet valve and a bypass valve are set between the gas compressor and the gas purification system. The inlet valve is connected to the gas purification system. When the gas compressor delivers gas to the gas tank, the inlet valve is opened and the bypass valve is closed. When the gas compressor stops delivering gas to the gas tank, the bypass valve is opened and the inlet valve is closed to ensure the stability of the calorific value of the mixed gas. In the fourth part, the gas that has been mixed, pressurized, and purified enters the gas tank intermittently through the automatic frequency conversion setting of the gas compressor. The gas tank triggers the closing and opening of the gas tank inlet valve according to the upper and lower limits of the gas tank capacity, thereby realizing automatic control of the gas tank.

2. The method for full-process automatic control of a gas system according to claim 1, characterized in that: In the first part, the blast furnace gas flow rate and coke oven gas flow rate are set according to the following: Blast furnace gas flow rate = [(coke oven gas calorific value - high coke mixed gas calorific value) / (coke oven gas calorific value - blast furnace gas calorific value)] × high coke mixed gas volume; Coke oven gas flow rate = [(calorific value of high-coke mixed gas - calorific value of blast furnace gas) / (calorific value of coke oven gas - calorific value of blast furnace gas)] × high-coke mixed gas volume.

3. The method for full-process automatic control of a gas system according to claim 1, characterized in that: In the second part, when the outlet pressure of the gas compressor is set to be greater than the saturation pressure value, the blast furnace gas flow regulating butterfly valve is automatically opened and automatic mixing adjustment begins; when the outlet pressure of the gas compressor is set to be less than the saturation pressure value, the blast furnace gas flow regulating butterfly valve is automatically closed and mixing adjustment stops.

4. The method for full-process automatic control of a gas system according to claim 1, characterized in that: In the second part, the gas tank adopts 20,000m 3 The saturated pressure value of the gas tank is 12kPa. When the gas tank capacity reaches a high level, the gas compressor automatically sets the outlet pressure to 11kPa. When the gas tank capacity drops to a low level, the gas compressor automatically sets the outlet pressure to 13kPa.

5. The method for full-process automatic control of a gas system according to claim 1, characterized in that: In the third part, the bypass valve is connected to the regeneration system.

6. The method for full-process automatic control of a gas system according to claim 1, characterized in that: In the third part, the coal gas purification system includes a desulfurization tower and a naphthalene removal tower.

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