Control method for coke oven gas system without gas holder buffering

Abstract

The invention belongs to the technical field of coking production process control, and provides a control method for a coke oven gas system without gas holder buffering, which comprises the following steps of: adjusting the load of a pressurizing machine as a measure for balancing the coke oven gas system, increasing the load when gas is excessive, and reducing the load when the gas is in shortage; coke oven gas pressure is stabilized for users by means of releasing coke oven gas and supplementing natural gas to coke oven gas, normal production of coking and coke oven gas rear users is ensured, efficient utilization of self-produced coke oven gas during simultaneous exit of two coke oven gas cabinets is realized, and natural gas is prevented from being added and introduced. And valuable technical experience is provided for stable operation of gas systems in the same industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of coking production process control, relates to the stable operation control of the coke oven gas system, and specifically is a control method for the coke oven gas system without the buffer of a gas holder. Background Art

[0002] Generally, a gas holder is provided in the coke oven gas system to play a role in peak shaving and voltage stabilization. When all gas holders are taken out for maintenance or fail to operate due to faults, without the buffer of the gas holder, the excess or shortage of coke oven gas will cause abnormal system pressure, which will have a great impact on the company's production.

[0003] Through analysis and research, in the case of no gas holder participating in buffering, the load of the booster can be adjusted as a measure to balance the system. Increase the load when there is excess gas, and reduce the load when there is a shortage of gas. And the pressure of the coke oven gas supplied to users is stabilized by discharging coke oven gas and supplementing coke oven gas with natural gas, ensuring the normal production of the coking and the users at the rear of the coke oven gas. Summary of the Invention

[0004] The purpose of the present invention is to provide a control method for the coke oven gas system without the buffer of a gas holder, to solve the problem of ensuring the stability of the outlet pressure of the coking blower and the pressure of high-pressure coke oven gas users, and not affecting the normal production of the rear users when the coke oven gas system has no gas holder for peak shaving or voltage stabilization.

[0005] The technical solution adopted by the present invention to achieve the above purpose is as follows:

[0006] A control method for the coke oven gas system without the buffer of a gas holder, including: S1. Upgrade the low-pressure coke oven booster to a coke oven high-pressure machine, and add a pressure transmitter to the inlet pipeline of the coke oven high-pressure machine. Interlock the inlet guide vane and the inlet pressure of the coke oven high-pressure machine, and set it to automatically adjust by tracking the inlet pressure. Stabilize the outlet pressure of the coking plant blower through the automatic adjustment of the load of the coke oven high-pressure machine; S2. Connect the high-pressure coke oven gas pipeline to the main body of the blast furnace gas flare tower for igniting and discharging coke oven gas. At the same time, add a high-pressure coke oven gas pressure transmitter, interlock the coke oven gas discharge regulating valve and the high-pressure coke oven gas pressure, and set it to automatically adjust by tracking the high-pressure coke oven gas pressure. Adjust the pressure of the high-pressure coke oven gas network through the automatic discharge of coke oven gas; S3. Connect the natural gas pipeline and the natural gas distribution valve group of the mixing system to the coke oven gas pipeline of the hot strip mill mixing system. Through the control system, interlock the gas and natural gas regulating valves of the mixing system with the high-pressure coke oven gas pressure, and set it to automatically adjust by tracking the high-pressure coke oven gas pressure. Automatically supplement natural gas through the mixing system.

[0007] Furthermore, the coke oven high-pressure machine adopts a single-suction double-supported centrifugal blower with a boosting capacity of 13.5 - 14.5 Kpa, a maximum gas flow rate of 30,000 m3 / h, and is equipped with an explosion-proof variable-frequency motor. The pressure is regulated by combining frequency conversion with imported guide vanes.

[0008] Furthermore, the imported guide vanes of the coke oven high-pressure machine are interlocked with the imported pressure. The automatic regulation of tracking the imported pressure adopts PID control. According to the dynamic and steady-state performance of the system, the PID control parameters are adjusted to the optimal state through experiments and debugging.

[0009] Furthermore, the coke oven gas discharge regulating valve adopts a zero-leakage electric-sealed butterfly valve.

[0010] Furthermore, the control system unifies the coke oven gas high-pressure machine and the gas mixing system into a DCS intensive control mode, which has a remote control function. Important signals such as the imported pressure of the high-pressure machine, the outlet pressure of the blower, the pressure of the high-pressure coke oven gas, the pressure and flow rate of the coke oven gas in the hot strip mill mixing system, the flow rate of natural gas, the calorific value of the gas, the opening degree of the imported guide vane regulating valve of the coke oven high-pressure machine, the opening degree of the coke oven gas discharge regulating valve, and the opening degree of the regulating valves of the coke oven gas and natural gas in the mixing system are sent into the control system. The opening degree of the butterfly valve can be automatically adjusted by the microcomputer according to the change of pressure or calorific value to control the gas flow rate.

[0011] The beneficial effects of the present invention are as follows: Without the peak shaving and pressure stabilizing functions of the gas holder, it can ensure the stability of the outlet pressure of the coking blower and the pressure of the high-pressure coke oven gas users, ensure the effective utilization of the self-produced coke oven gas in the coking plant, avoid the discharge of coke oven gas, reduce the additional introduction of natural gas for production guarantee, and at the same time meet the normal production of the coking plant and the coke oven gas users, creating conditions for ensuring the safe, stable and smooth operation of the enterprise, and providing technical experience for the stable operation of the gas system in the same industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic diagram of the transformation scheme of the embodiment of the present invention; In the figure: 1. Coke oven high-pressure machine; 2. Coke oven gas high-low pressure connection door; 3. Gas holder; 4. Blast furnace No. 3 gas discharge tower; 5. Blast furnace No. 5 gas discharge tower; 6. Coke oven gas discharge regulating valve; 7. Gas mixing system; 8. Natural gas regulating valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] The following further describes the present invention in conjunction with the drawings and embodiments: A control method for a coke oven gas system without a gas holder buffer includes: S1. Upgrade the low-pressure coke oven blower to a high-pressure coke oven blower, and add a pressure transmitter to the inlet pipeline of the high-pressure coke oven blower. The high-pressure coke oven blower adopts a single-suction double-support centrifugal blower with a pressure boosting capacity of 13.5 - 14.5 Kpa and a maximum gas flow rate of 30,000 m³ / h, equipped with an explosion-proof variable-frequency motor. The pressure is adjusted by combining frequency conversion with an inlet guide vane. Interlock the inlet guide vane and the inlet pressure of the high-pressure coke oven blower, set it to automatically adjust by tracking the inlet pressure, and stabilize the outlet pressure of the coking plant blower by automatically adjusting the load of the high-pressure coke oven blower. The automatic adjustment by tracking the inlet pressure adopts PID control. According to the dynamic and steady-state performance of the system, adjust the PID control parameters to the optimal state through experiments and debugging. When there is surplus coke oven gas, the high-pressure coke oven blower supplies the surplus coke oven gas to the high-pressure coke oven gas pipeline network. When there is a shortage of coke oven gas, the high-pressure coke oven blower reduces the amount of high-pressure coke oven gas supplied externally; S2. Connect a high-pressure coke oven gas pipeline to the main body of the blast furnace gas relief tower for igniting and discharging coke oven gas. At the same time, add a pressure transmitter for high-pressure coke oven gas, interlock the coke oven gas discharge regulating valve and the high-pressure coke oven gas pressure, set it to automatically adjust by tracking the high-pressure coke oven gas pressure, and adjust the pressure of the high-pressure coke oven gas pipeline network by automatically discharging coke oven gas to solve the problem of high pressure in the high-pressure coke oven gas pipeline network. The coke oven gas discharge regulating valve adopts a zero-leakage electric-sealed butterfly valve. When there is surplus coke oven gas, the pressure of the high-pressure coke oven gas pipeline network rises. After exceeding the set value, the blast furnace gas relief tower discharges the surplus coke oven gas. After the pressure returns to normal, the discharge is closed; S3. Connect a natural gas pipeline and a natural gas distribution valve group for the mixed system in the hot strip mill mixed system coke oven gas pipeline. Through the control system, interlock the gas and natural gas regulating valves in the mixed system and the high-pressure coke oven gas pressure, set it to automatically adjust by tracking the high-pressure coke oven gas pressure, automatically supplement natural gas through the mixed system to solve the problem of low pressure in the high-pressure coke oven gas pipeline network, and at the same time achieve the control of the calorific value of the mixed gas. When there is a shortage of coke oven gas, the pressure of the high-pressure coke oven gas pipeline network drops. After falling below the set value, the hot strip mill mixed system automatically increases the amount of natural gas blended, and at the same time the consumption of coke oven gas decreases accordingly. After the pressure returns to normal, the mixed system reduces the amount of natural gas blended. The control system unifies the high-pressure coke oven gas blower and the gas mixing system into a DCS intensive control mode, with remote control function. Send important signals such as the inlet pressure of the high-pressure blower, the outlet pressure of the blower, the high-pressure coke oven gas pressure, the coke oven gas pressure and flow rate in the hot strip mill mixed system, the natural gas flow rate, the gas calorific value, the opening degree of the inlet guide vane regulating valve of the high-pressure coke oven blower, the opening degree of the coke oven gas discharge regulating valve, and the opening degrees of the coke oven gas and natural gas regulating valves in the mixed system into the control system. The opening degree of the butterfly valve can be automatically adjusted by the microcomputer according to the change of pressure or calorific value to control the gas flow rate. Example

[0014] The Energy Department of the company applies the control method of the coke oven gas system without gas holder buffer in the present invention to actual production, such asFigure 1 As shown below: S1. Upgrading and transformation of coke oven gas booster (1) Three coke oven gas boosters are transformed from coke oven low-pressure machines with a pressure boost of 10 KPa to coke oven high-pressure machines with a pressure boost of 15 KPa. The maximum gas transportation capacity of each coke oven high-pressure machine 1 is 30,000 m³ / h. The coke oven high-pressure machine 1 adopts a single-suction double-supported centrifugal blower, with a supporting explosion-proof variable-frequency motor power of 250 Kw, IP54, F-class insulation, explosion-proof grade dⅡBT4, motor voltage: 380V, and motor speed: 2980 rpm. The high-pressure coke oven gas systems of the whole company are interconnected through the high-low pressure connection gate 2 of coke oven gas, creating conditions for the automatic control and adjustment of the system after all gas holders 3 are withdrawn;

[0015] (2) A pressure transmitter is added to the inlet pipeline of the coke oven high-pressure machine 1 to interlock the inlet guide vane and inlet pressure of the coke oven high-pressure machine 1, and the PID parameters are adjusted to the optimal state.

[0016] S2. Upgrading and transformation of coke oven gas ignition and blow-off (1) The main bodies of the blow-off towers 4 of the No. 3 blast furnace and the blow-off tower 5 of the No. 5 blast furnace are respectively connected to the high-pressure coke oven gas pipeline, and a regulating valve 6 is installed on the high-pressure coke oven gas pipeline, which has the functions of igniting and blowing off coke oven gas and adjusting the blow-off volume, with a coke oven gas blow-off capacity of 60,000 m³ / h;

[0017] (2) A high-pressure coke oven gas pressure transmitter and a flowmeter are added to the coke oven gas pipeline at the blow-off tower to interlock the coke oven gas blow-off regulating valve and the high-pressure coke oven gas pressure.

[0018] S3. Developing an intelligent control system for the calorific value of mixed gas The coke oven gas pipeline in the hot strip mill mixing system 7 is connected to the natural gas pipeline, which has the function of replacing coke oven gas with natural gas. The natural gas blending capacity is 18,000 m³ / h, and it can supplement the maximum coke oven gas gap of 36,000 m³ / h.

[0019] A pressure transmitter is added to the coke oven gas pipeline in the hot strip mill mixing system to interlock the natural gas regulating valve 8 in the mixing system 7 and the high-pressure coke oven gas pressure, and to interlock the coke oven gas regulating valve, the natural gas regulating valve 8 in the mixing system 7 and the calorific value of the mixed gas.

[0020] When the gas holder 3 is taken out of operation, after applying the above technical transformation plan, the inlet pressure of the coke oven high-pressure machine 1 is in the range of 4.5 - 5.5 KPa, and the outlet pressure of the coke oven high-pressure machine 1 is in the range of 13 - 16 KPa, meeting the normal production of the coking plant and coke oven gas users, creating conditions for ensuring the stable and smooth operation of safe production, and at the same time avoiding a large amount of self-produced coke oven gas being blown off and increasing the additional introduction of natural gas for production protection.

Claims

1. A control method for a coke oven gas system without gas cabinet buffering, characterized in that: include: S1. Upgrade the low-pressure coke oven pressurizer to a coke oven high-pressure machine, add a pressure transmitter to the inlet pipeline of the coke oven high-pressure machine, interlock the inlet guide vane of the coke oven high-pressure machine with the inlet pressure, set it to track the automatic adjustment of the inlet pressure, and stabilize the outlet pressure of the coking plant blower through the automatic load adjustment of the coke oven high-pressure machine; S2. Connect a high-pressure coke oven gas pipeline to the blast furnace discharge tower body for igniting and discharging coke oven gas. At the same time, add a high-pressure coke oven gas pressure transmitter, interlock the coke oven gas discharge regulating valve and the high-pressure coke oven gas pressure, set it to track the high-pressure coke oven gas pressure and automatically adjust it, and adjust the high-pressure coke oven pipe network pressure by automatically discharging the coke oven gas; S3. Connect the natural gas pipeline and the natural gas distribution valve group of the hot rolling mixing system coke oven gas pipeline, interlock the mixing system gas and natural gas regulating valves and the high-pressure coke oven gas pressure through the control system, set it to automatically adjust the tracking high-pressure coke oven gas pressure, and automatically replenish natural gas through the mixing system.

2. The control method of a coke oven gas system without gas cabinet buffering according to claim 1 is characterized in that: The coke oven high pressure machine adopts a single-suction double-support centrifugal blower with a boost capacity of 13.5-14.5Kpa and a maximum gas flow rate of 30,000m3 / h. It is equipped with an explosion-proof variable frequency motor and pressure is adjusted by frequency conversion combined with inlet guide vanes.

3. The control method of a coke oven gas system without gas cabinet buffering according to claim 1 is characterized in that: The inlet guide vane of the coke oven high pressure machine is interlocked with the inlet pressure, and the automatic adjustment of tracking the inlet pressure adopts PID control. According to the dynamic performance and steady-state performance of the system, the PID control parameters are adjusted to the optimal state through experiments and debugging.

4. The control method of a coke oven gas system without gas cabinet buffering according to claim 1 is characterized in that: The coke oven gas release regulating valve adopts a zero-leakage electric sealing butterfly valve.

5. The control method of a coke oven gas system without gas cabinet buffering according to claim 1, characterized in that: The control system unifies the coke oven gas high pressure machine and the gas mixing system into a DCS intensive control mode, and has a remote control function. The high pressure machine inlet pressure, blower outlet pressure, high pressure coke oven gas pressure, hot rolling mixing system coke oven gas pressure and flow, natural gas flow, gas calorific value, coke oven high pressure machine inlet guide vane regulating valve opening, coke oven gas release regulating valve opening, mixing system coke oven gas and natural gas regulating valve opening signals are sent to the control system. The microcomputer can automatically adjust the butterfly valve opening according to the pressure or calorific value changes to control the gas flow.

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