A mixed gas system for carbon baking

Abstract

The utility model relates to a gas application technical field, concretely is a kind of mixed coal gas system of carbon baking, including electric furnace coal gas delivery pipeline, natural gas delivery pipeline and natural gas mixed gas path, electric furnace coal gas delivery pipeline has primary pressurizing pipeline and secondary pressurizing pipeline, electric furnace coal gas delivery pipeline is mixed with natural gas delivery pipeline and forms natural gas mixed gas path, primary pressurizing pipeline is equipped with pressure constant value control loop, safety interlock loop is equipped between primary pressurizing pipeline and secondary pressurizing pipeline, secondary pressurizing pipeline has flow ratio control loop, the utility model is based on natural gas mixed gas system of single closed loop flow ratio control loop, through preset K value dynamic regulation electric proportional regulating valve opening, make mixed coal gas calorific value stable control in set range, compared with traditional mixed gas mode calorific value precision significantly improves, the utility model integrates the double-channel feedback mechanism of coal gas flowmeter and natural gas flowmeter, makes carbon baking process improve stability, high security.

Description

Technical Field

[0001] This utility model relates to the field of gas application technology, specifically to a mixed gas system for carbon roasting. Background Technology

[0002] In existing technologies, the mixed gas systems used in carbon roasting processes generally suffer from technical defects such as insufficient gas supply stability, weak safety protection measures, and low precision in mixing ratio control. Traditional low-heat gas supply systems typically rely on a single gas source (such as electric furnace gas or low-heat self-produced gas). When the buffer gas holder is under maintenance, gas supply can only be maintained through a single gas source, making production highly susceptible to interruptions due to fluctuations in gas source pressure. In particular, when the electric furnace gas inlet pressure is below a critical value, the lack of an effective interlocking protection mechanism may lead to overload or shutdown risks for pressurization equipment.

[0003] Furthermore, existing mixed gas systems often employ open-loop control or simple PID regulation for pressure regulation, which struggles to adapt to dynamic demands under complex operating conditions. This results in significant fluctuations in outlet pressure, impacting subsequent combustion efficiency. In the natural gas mixing stage, traditional methods rely on fixed valve openings or manual ratio adjustments, making it difficult to achieve real-time, precise proportions of natural gas and electric furnace gas. This leads to fluctuations in the calorific value of the mixed gas exceeding the process allowable range, thereby reducing product roasting quality. Particularly in scenarios involving the mixing of high-calorific-value natural gas and low-calorific-value coal gas, proportional control errors can cause calorific value deviations exceeding ±5%, severely restricting the standardization and automation of the production process.

[0004] Therefore, there is an urgent need to develop a mixed gas system to solve the above problems. Utility Model Content

[0005] This invention relates to a mixed gas system. The system features a pressure setpoint control loop in the primary pressurization pipeline, a safety interlock loop between the primary and secondary pressurization pipelines, and a flow ratio control loop in the secondary pressurization pipeline. These features improve the safety and production efficiency of the mixed gas system and effectively solve the aforementioned technical problems.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a mixed gas system for carbon roasting, comprising: an electric furnace gas transmission pipeline, a natural gas transmission pipeline, and a natural gas mixing pipeline. The electric furnace gas transmission pipeline has a primary pressurization pipeline and a secondary pressurization pipeline. The electric furnace gas transmission pipeline and the natural gas transmission pipeline are mixed to form a natural gas mixing pipeline. The primary pressurization pipeline is equipped with a pressure setpoint control loop. A safety interlocking loop is provided between the primary pressurization pipeline and the secondary pressurization pipeline. The secondary pressurization pipeline has a flow ratio control loop.

[0007] Preferably, the electric furnace gas transmission pipeline further includes a primary low-heat gas supply pipeline, an industrial tail gas supply pipeline, and a buffer gas holder. The primary low-heat gas supply pipeline is pressurized by a primary pressurization pipeline and then connected to the industrial tail gas supply pipeline. The inlet end of the primary low-heat gas supply pipeline is equipped with a pressure electric regulating valve. A buffer gas holder is provided on one side of the primary low-heat gas supply pipeline, and a butterfly valve is provided between the primary low-heat gas supply pipeline and the buffer gas holder.

[0008] Preferably, the primary pressurization pipeline includes a frequency converter for the exhaust fan, a pressure setpoint PID regulator, a check valve, a pressure gauge, and a pressure gauge. The pressure gauge is connected in parallel with the check valve, and a gate valve is provided between the pressure gauge and the check valve. The pressure gauge is located at the outlet end of the primary pressurization pipeline. The pressure setpoint PID regulator is electrically connected to the pressure electric regulating valve, the exhaust fan frequency converter, and the pressure gauge.

[0009] Preferably, the pressure setpoint control loop includes a second pressure electric regulating valve and a second pressure setpoint PID controller. The second pressure electric regulating valve is located at the inlet end after the primary low-heat gas supply pipeline and the industrial tail gas supply pipeline are mixed. A third pressure gauge is provided at the front end of the secondary pressurization pipeline. The second pressure setpoint PID controller is electrically connected to the third pressure gauge, and the second pressure electric regulating valve is electrically connected to the second pressure setpoint PID controller.

[0010] Preferably, after the primary low-heat coal gas supply pipeline mixes with the industrial tail gas supply pipeline, the gas enters the secondary pressurization pipeline. The secondary pressurization pipeline includes a secondary pressurization inlet valve, a secondary pressurizer, a secondary pressurization outlet electric pressure valve, a pressure gauge, and a coal gas flow meter.

[0011] Preferably, the safety interlock circuit is equipped with a pressure safety interlock controller, one side of the safety interlock circuit is electrically connected to the pressure gauge, and the other side of the safety interlock circuit is electrically connected to the secondary pressurization outlet pneumatic electric valve.

[0012] Preferably, when the pressure detected by the safety interlock circuit is lower than the set safety threshold, the secondary pressurization outlet air pressure electric valve is closed and the secondary pressurizer is stopped.

[0013] Preferably, the natural gas transmission pipeline includes a natural gas flow meter, an electric proportional regulating valve, and a ball valve.

[0014] Preferably, the flow ratio control loop has a single closed-loop flow ratio controller, which is electrically connected to a gas flow meter, a natural gas flow meter, and an electric proportional regulating valve.

[0015] Preferably, the flow ratio controller is configured to maintain a constant ratio between the natural gas flow rate and the electric furnace gas flow rate by controlling the opening of the second electric regulating valve according to a preset ratio coefficient K.

[0016] Beneficial effects

[0017] This utility model provides a mixed gas system, which has the following advantages compared with the existing technology:

[0018] This invention significantly improves the safety and operating efficiency of the carbon roasting mixed gas system through a graded pressurization architecture and an intelligent control system.

[0019] This utility model adopts a two-stage pressurization design with a primary pressurization pipeline and a secondary pressurization pipeline. With the coordinated control of the pressure setpoint PID controller one, the pressure setpoint PID controller two and the pressure electric regulating valve two, the inlet pressure of the electric furnace gas can be stably maintained at 300 mmH2O, which reduces the pressure fluctuation amplitude compared with the traditional system.

[0020] In this invention, when the pressure gauge reading is below 1 kPa, the safety interlock circuit can immediately trigger the secondary pressurizer shutdown protection, effectively preventing equipment no-load losses and safety accidents.

[0021] During maintenance, this invention can ensure the minimum gas supply load through the direct gas supply mode of the electric furnace. Combined with the interlocking configuration of the check valve and the blind valve, it can achieve seamless switching between the two gas sources and improve the reliability of the gas supply.

[0022] This utility model is a natural gas mixing system based on a single closed-loop flow ratio control loop. By dynamically adjusting the opening of the electric proportional regulating valve through a preset K value, the calorific value of the mixed gas is stably controlled within the set range, which significantly improves the calorific value accuracy compared with the traditional mixing method.

[0023] This utility model also integrates a dual-channel feedback mechanism of coal gas flow meter and natural gas flow meter, and with the help of pressure safety interlock controller, it can complete the pressure abnormality response in a short time, reduce overall energy consumption, and provide a gas supply solution with high stability, high safety and high controllability for carbon roasting process. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the planar structure of this utility model;

[0026] Figure 2 This is a schematic diagram of the planar structure of the electric furnace gas transmission pipeline of this utility model;

[0027] Figure 3 This is a schematic diagram of the planar structure of the natural gas transmission pipeline and natural gas mixing pipeline of this utility model;

[0028] Figure 4 This is a trend chart showing the data changes after mixing natural gas and electric furnace gas under CNC control according to this utility model;

[0029] In the picture:

[0030] 1. Primary pressurization pipeline; 2. Secondary pressurization pipeline; 3. Pressure setpoint control loop; 4. Safety interlock loop; 5. Flow ratio control loop; 6. Buffer gas holder; 7. Pressure electric regulating valve one; 8. Blind valve; 9. Exhaust fan frequency converter; 10. Pressure setpoint PID controller one; 11. Check valve; 12. Pressure gauge one; 13. Pressure gauge two; 14. Pressure electric regulating valve two; 15. Pressure setpoint PID controller two; 16. Pressure gauge three; 17. Secondary pressurization inlet valve; 18. Secondary pressurization machine; 19. Secondary pressurization outlet gas pressure electric valve; 20. Gas flow meter; 21. Pressure safety interlock controller; 22. Natural gas flow meter; 23. Electric proportional regulating valve; 24. Single closed-loop flow ratio controller. Detailed Implementation

[0031] To make the technical problems, technical solutions and beneficial effects of this utility model clearer, this utility model will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model. The technical solutions of this utility model will be described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0032] Please see Figure 1-4 This utility model provides a technical solution:

[0033] This invention provides a mixed gas system for carbon roasting, which achieves stable mixing and safe supply of low-heat coal gas and natural gas through the coordinated design of a staged pressurization architecture and an intelligent control system.

[0034] The overall architecture of this utility model system includes three major modules: electric furnace gas transmission pipeline, natural gas transmission pipeline, and natural gas mixing pipeline. The electric furnace gas transmission pipeline has a primary pressurization pipeline 1 and a secondary pressurization pipeline 2. The electric furnace gas transmission pipeline and the natural gas transmission pipeline are mixed to form a natural gas mixing pipeline. The primary pressurization pipeline 1 is equipped with a pressure setpoint control loop 3. A safety interlocking loop 4 is provided between the primary pressurization pipeline 1 and the secondary pressurization pipeline 2. The secondary pressurization pipeline 2 is equipped with a flow ratio control loop 5.

[0035] In some embodiments, the primary pressurization pipeline 1 is equipped with a centrifugal fan driven by a frequency converter 9 for the exhaust fan. An electric pressure regulating valve 7 is installed at the inlet, and a pressure gauge 12, a pressure setpoint PID controller 10, a check valve 11, and a pressure gauge 13 are sequentially installed at the outlet. The primary low-heat gas supply pipeline is equipped with a check valve 11 to prevent industrial exhaust gas from mixing with the low-heat gas system, ensuring gas supply safety.

[0036] In some embodiments, the electric furnace gas transmission pipeline is further equipped with a buffer gas holder 6. The connecting pipelines to the buffer gas holder 6 are all equipped with butterfly valves. After the primary low-heat gas supply pipeline and the industrial tail gas supply pipeline mix, the mixture can enter the buffer gas holder 6 as a whole. The buffer gas holder 6 can provide a stable gas supply to the secondary pressurization pipeline 2, and in the event of a gas supply interruption, the gas holder can maintain a minimum load to stabilize the gas source pressure and flow.

[0037] When the buffer gas holder 6 is under maintenance, the butterfly valves at both ends of the buffer gas holder 6 are closed to isolate the gas source. After the primary low-heat coal gas supply pipeline and the industrial tail gas supply pipeline are mixed, the gas enters the secondary pressurization pipeline 2 through the pipeline above the buffer gas holder 6, so as to achieve maintenance without production interruption and leave enough time for safe operation to avoid safety accidents.

[0038] In some embodiments, a secondary pressurization inlet valve 17 is provided at the inlet of the secondary pressurization pipeline 2, the core equipment is a secondary pressurizer 18, and a secondary pressurization outlet gas pressure electric valve 19, a gas flow meter 20 and a pressure gauge 16 are installed sequentially at the outlet.

[0039] In some embodiments, the primary pressurization line 1 has a pressure setpoint control loop 3, which has a function similar to the pressure setpoint control loop 3 in the secondary pressurization line 2, and controls the air flow rate at the inlet end of the primary pressurization line 1.

[0040] In some embodiments, the natural gas transmission pipeline includes a ball valve, an electric proportional control valve 23 and a flow meter, and is configured with a vent valve and a pressure sensor via a bypass pipeline.

[0041] In some embodiments, the natural gas mixing circuit is equipped with a single closed-loop flow ratio controller 24. Secondary pressurized coal gas and natural gas are combined according to a preset ratio via the single closed-loop flow ratio controller 24 and then transported to the roasting furnace through the main pipeline. An online calorific value analyzer and an emergency shut-off valve are installed on the main pipeline of the natural gas mixing circuit.

[0042] In some embodiments, after the system starts, the electric furnace gas first enters the primary pressurization pipeline 1, where it is pressurized by a centrifugal fan driven by the frequency converter 9 of the exhaust fan. The pressure electric regulating valve 7 at the inlet end dynamically adjusts its opening according to the feedback signal of the pressure setpoint PID controller 10, ensuring that the primary pressurization outlet pressure is stable at the set value (default 300 mmH2O, adjustable range 100-500 mmH2O). Pressure gauge 12 monitors the inlet pressure in real time, while pressure gauge 13 feeds back the outlet pressure to the pressure setpoint PID controller 15 to form a closed loop.

[0043] In some embodiments, when the pressure setpoint PID controller 15 detects that the pressure of the pressure gauge is not within the predetermined range, it adjusts the opening and closing degree of the pressure electric regulating valve 14 in real time to adjust the air intake from the secondary pressurization pipeline 2.

[0044] In some embodiments, when the inlet pressure of the secondary pressurization line 2 is detected to be lower than the safety threshold of 1 kPa, the pressure safety interlock controller 21 immediately triggers the shutdown command of the secondary pressurizer 18 and closes the outlet air pressure electric valve to prevent the equipment from running under no-load.

[0045] In some embodiments, the core of the secondary pressurization pipeline 2 of this utility model is a secondary pressurizer 18. The pressurizer has a variable frequency speed control function. A pressure gauge 16 is installed at the inlet, and a secondary pressurization inlet valve 17 is set at the inlet. A secondary pressurization outlet gas pressure electric valve 19 and a gas flow meter 20 are installed sequentially at the outlet. The signal from the gas flow meter 20 and the signal from the natural gas flow meter 22 are input together to a single closed-loop proportional controller. The controller dynamically adjusts the opening of the electric proportional regulating valve 23 according to a preset proportional coefficient K (e.g., K = 0.046, corresponding to a natural gas ratio of 4.6%), so that the calorific value of the mixed gas is stabilized at 3000±50 kcal / Nm³. 3 A static mixer is installed at the end of the mixing gas path to promote uniform mixing, and an online calorific value analyzer is installed on the main pipeline to monitor calorific value fluctuations in real time and to trigger an emergency shut-off valve to deal with situations where the calorific value exceeds the standard.

[0046] In some embodiments, the system of this utility model is equipped with a multi-interlock mechanism. When the outlet pressure of the secondary compressor 18 is >5kPa or <1kPa, the pressure safety interlock controller 21 immediately cuts off the power supply to the electric proportional regulating valve 23 and triggers an audible and visual alarm. The pressure sensor of the buffer gas holder 6 monitors the pressure change rate. If the pressure drop rate is >0.2kPa / s for 30 consecutive seconds, the natural gas electric valve is automatically closed and the system switches to the pure electric furnace gas supply mode. In addition, key nodes such as the junction of electric furnace gas and low-heat gas and the outlet of the buffer gas holder 6 are equipped with 11 sets of bidirectional check valves to prevent cross-contamination of gas sources and resulting fluctuations in calorific value.

[0047] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. For those skilled in the art to which the present invention pertains, simple deductions or substitutions can be made without departing from the present invention, and all such deductions or substitutions should be considered as falling within the scope of patent protection determined by the submitted claims.

Claims

1. A mixed gas system for carbon roasting, characterized in that, include: The system includes an electric furnace gas transmission pipeline, a natural gas transmission pipeline, and a natural gas mixing pipeline. The electric furnace gas transmission pipeline has a primary pressurization pipeline and a secondary pressurization pipeline. The electric furnace gas transmission pipeline and the natural gas transmission pipeline are mixed to form a natural gas mixing pipeline. The primary pressurization pipeline is equipped with a pressure setpoint control loop. A safety interlocking loop is provided between the primary pressurization pipeline and the secondary pressurization pipeline. The secondary pressurization pipeline has a flow ratio control loop.

2. The mixed gas system according to claim 1, characterized in that, The electric furnace gas transmission pipeline also includes a primary low-heat gas supply pipeline, an industrial tail gas supply pipeline, and a buffer gas holder. The primary low-heat gas supply pipeline is pressurized by a primary pressurization pipeline and then connected to the industrial tail gas supply pipeline. The inlet end of the primary low-heat gas supply pipeline is equipped with a pressure electric regulating valve. A buffer gas holder is provided on one side of the primary low-heat gas supply pipeline, and a butterfly valve is provided between the primary low-heat gas supply pipeline and the buffer gas holder.

3. The mixed gas system according to claim 2, characterized in that, The primary pressurization pipeline includes a frequency converter for the exhaust fan, a pressure setpoint PID controller, a check valve, a pressure gauge, and a pressure gauge. The pressure gauge is connected in parallel with the check valve, and a gate valve is provided between the pressure gauge and the check valve. The pressure gauge is located at the outlet end of the primary pressurization pipeline. The pressure setpoint PID controller is electrically connected to the pressure electric regulating valve, the exhaust fan frequency converter, and the pressure gauge.

4. The mixed gas system according to claim 3, characterized in that, The pressure setpoint control loop includes a second pressure electric regulating valve and a second pressure setpoint PID controller. The second pressure electric regulating valve is located at the inlet end of the primary low-heat gas supply pipeline and the industrial tail gas supply pipeline after mixing. A third pressure gauge is installed at the front end of the secondary pressurization pipeline. The second pressure setpoint PID controller is electrically connected to the third pressure gauge, and the second pressure electric regulating valve is electrically connected to the second pressure setpoint PID controller.

5. The mixed gas system according to claim 4, characterized in that, After the primary low-heat coal gas supply pipeline mixes with the industrial tail gas supply pipeline, the gas enters the secondary pressurization pipeline. The secondary pressurization pipeline includes a secondary pressurization inlet valve, a secondary pressurizer, a secondary pressurization outlet electric pressure valve, a pressure gauge, and a coal gas flow meter.

6. The mixed gas system according to claim 5, characterized in that, The safety interlock circuit is equipped with a pressure safety interlock controller. One side of the safety interlock circuit is electrically connected to the pressure gauge, and the other side of the safety interlock circuit is electrically connected to the secondary pressurization outlet pneumatic electric valve.

7. The mixed gas system according to claim 6, characterized in that, When the pressure detected by the safety interlock circuit is lower than the set safety threshold, the secondary pressurization outlet air pressure electric valve is closed and the secondary pressurizer is stopped.

8. The mixed gas system according to claim 7, characterized in that, The natural gas transmission pipeline is equipped with a natural gas flow meter, an electric proportional regulating valve, and a ball valve.

9. The mixed gas system according to claim 8, characterized in that, The flow ratio control loop has a single closed-loop flow ratio controller, which is electrically connected to a gas flow meter, a natural gas flow meter, and an electric proportional regulating valve.

10. The mixed gas system according to claim 9, characterized in that: The flow ratio controller is configured to maintain a constant ratio between the natural gas flow rate and the electric furnace gas flow rate by controlling the opening of the second electric regulating valve according to a preset ratio coefficient K.

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