A coke oven gas pipeline at the inlet of a combustion furnace of a blast furnace coal injection system
Patent Information
- Application Number
- CN202521924272.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-08
- Publication Date
- 2026-09-11
- Estimated Expiration
- 2035-09-08
AI Technical Summary
但此过程中，若煤气流量不稳定，即便计算出了煤粉流量并通过调节阀门开度来调整，也难以保证煤粉稳定输送，因为煤气作为输送载体，其流量波动会持续干扰煤粉的输送状态
1、本装置中，切断阀关闭后可完全阻断高炉煤气主管道的冗余煤气通道，仅通过旁通管道供应煤气，可直接降低煤气输送过程中的无效流量损耗，使单炉高炉煤气用量从400-600m3/h降至100-300m3/h，同时减少氮气、压缩空气的调节用量；此外，旁通管道为高炉煤气管道管径的1/2，小口径管道对流量变化的响应更灵敏，配合调节阀的精准控制，可将气体主管压力波动幅度有效控制，解决压力波动问题。
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Figure CN224741072U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of iron and steel smelting, and in particular to a coke oven gas pipeline at the inlet of a blast furnace pulverized coal injection system. Background Technology
[0002] The pulverized coal injection system in blast furnaces is a key piece of equipment for steel companies to reduce coke ratio and save costs. Currently, most pulverized coal injection systems in steel companies adopt dual-pipeline injection, but the mainstream dual-pipeline injection method has the following technical defects: First, the pulverized coal injection rate fluctuates greatly. Taking a certain plant as an example, the pulverized coal injection system for furnaces 6 and 7 is designed with an injection capacity of 50 t / h, but the actual injection rate fluctuates from 20 t / h to 60-70 t / h, affecting the stability of blast furnace smelting. This is mainly because the existing dual-pipeline pulverized coal injection system lacks precise control components for gas flow, resulting in inconsistent gas supply. For example, in some pulverized coal injection systems that use a weighing and control system for the injection tank, the total weight of the injection tank and the pulverized coal inside is collected by the weighing system. The PLC controller calculates the reduction of pulverized coal in the injection tank within the corresponding time interval based on the change in total weight, and then calculates the actual pulverized coal flow rate per unit time. However, if the gas flow rate is unstable, even if the pulverized coal flow rate is calculated and adjusted by regulating the valve opening, it is difficult to guarantee stable pulverized coal delivery, because the gas, as the transport carrier, will continuously interfere with the pulverized coal delivery status due to flow fluctuations. Second, the gas consumption is high and the pressure fluctuates. Adjusting the coal quantity in the dual-pipeline system requires a large amount of nitrogen and compressed air, resulting in large fluctuations in the main gas pressure, further exacerbating the instability of pulverized coal injection. Thirdly, there is the issue of pipeline wear and powder leakage. The dual-pipeline system, characterized by "more air than coal," cannot achieve dense-phase coal injection, resulting in a higher flow velocity within a single nozzle and severe wear on the single pipeline, leading to powder leakage. This not only pollutes the environment but also poses an explosion safety hazard. Utility Model Content
[0003] To address the aforementioned technical problems, a coke oven gas pipeline at the combustion furnace inlet of a blast furnace pulverized coal injection system is provided. The technical means employed in this invention are as follows: A coke oven gas pipeline at the inlet of a blast furnace pulverized coal injection system includes a blast furnace gas pipeline and a bypass pipeline. A shut-off valve is installed on the blast furnace gas pipeline, and a regulating valve is installed on the bypass pipeline. The shut-off valve is connected in series in the middle of the blast furnace gas pipeline. The two ends of the bypass pipeline are respectively welded to the blast furnace gas pipelines on both sides of the shut-off valve, and the welding points of the bypass pipeline and the blast furnace gas pipeline are all located at the lowest point of the blast furnace gas pipeline. The diameter of the bypass pipeline is 1 / 2 of the diameter of the blast furnace gas pipeline.
[0004] Furthermore, the bypass pipe is made of seamless steel pipe.
[0005] Furthermore, a flow meter is installed on the bypass pipe.
[0006] Furthermore, a vent pipe is provided on the bypass pipe, one end of which is welded to the bypass pipe, and the other end extends vertically upward with its top end higher than the top of the combustion furnace.
[0007] Furthermore, it also includes a purging assembly, which consists of several groups, each group of which includes a shut-off valve and a quick-connect flexible connector.
[0008] Furthermore, the purging assembly is welded to the pipe sections upstream of the flow meter of the bypass pipeline, downstream of the regulating valve, and between the shut-off valve and the manual valve of the blast furnace gas main pipeline.
[0009] This utility model has the following advantages: 1. In this device, the shut-off valve, once closed, completely blocks redundant gas channels in the main blast furnace gas pipeline, supplying gas only through the bypass pipeline. This directly reduces ineffective flow losses during gas transportation, lowering the gas consumption per blast furnace from 400-600 m³ / h. 3 / h decreased to 100-300m 3 / h, while reducing the amount of nitrogen and compressed air used for regulation; in addition, the bypass pipeline is half the diameter of the blast furnace gas pipeline. The small diameter pipeline is more sensitive to changes in flow rate. With the precise control of the regulating valve, the pressure fluctuation of the main gas pipeline can be effectively controlled, thus solving the pressure fluctuation problem.
[0010] 2. In this device, the gas flow rate is precisely controlled from the source by regulating the valve, avoiding fluctuations in the pulverized coal injection rate caused by inconsistent gas supply, and directly solving the problem of unstable pulverized coal injection rate.
[0011] 3. The bypass pipeline uses seamless steel pipe, which improves the wear resistance compared to existing pipelines; at the same time, the regulating valve can stably control the gas flow rate within the optimal flow rate range for dense phase pulverized coal injection, avoiding erosion and wear caused by excessive flow rate, reducing powder leakage and subsequent environmental hazards. Attached Figure Description
[0012] 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 some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0013] Figure 1 This is a schematic diagram of the structure of this utility model.
[0014] In the diagram: 1. Blast furnace gas pipeline; 2. Shut-off valve; 3. Bypass pipeline; 4. Regulating valve. Detailed Implementation
[0015] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0016] like Figure 1 As shown in the figure, this utility model discloses a coke oven gas pipeline at the combustion furnace inlet of a blast furnace pulverized coal injection system, including a blast furnace gas pipeline 1 and a bypass pipeline 3. A shut-off valve 2 is installed on the blast furnace gas pipeline, and a regulating valve 4 is installed on the bypass pipeline. The shut-off valve is connected in series in the middle of the blast furnace gas pipeline. The two ends of the bypass pipeline are welded to the blast furnace gas pipelines on both sides of the shut-off valve, and the welding points of the bypass pipeline and the blast furnace gas pipeline are all located at the lowest point of the blast furnace gas pipeline. The diameter of the bypass pipeline is half the diameter of the blast furnace gas pipeline. This small-diameter design improves flow response sensitivity. The shut-off valve is mainly used to block redundant channels in the main pipeline, and the regulating valve is used to precisely control the gas flow rate. In this embodiment, the diameter of the blast furnace gas pipeline is 600 mm, and the diameter of the bypass pipeline is 300 mm. This utility model, through the new process structure pipeline and the function of the regulating valve, can both regulate flow rate and control pressure. It saves the gas medium consumption during the pulverized coal injection process and plays a positive role in energy conservation and consumption reduction.
[0017] Optionally, the bypass pipe is inclined from high to low to ensure that condensate can flow into the main pipe drain valve along the inclined pipe, avoiding water accumulation that could cause pipe blockage or corrosion.
[0018] Optionally, a reserved flange is installed at a preset distance downstream of the regulating valve, and an asbestos gasket is used to seal between the flanges for subsequent installation of a spectacle valve for isolation and maintenance, so as to avoid secondary cutting of the pipeline from affecting production.
[0019] In some alternative embodiments, the shut-off valve and the regulating valve are manual valves; in some extended embodiments, the shut-off valve and the regulating valve are electrically controlled valves.
[0020] Furthermore, the bypass pipe is made of seamless steel pipe, which effectively improves its wear resistance.
[0021] Furthermore, a flow meter is installed on the bypass pipe. The flow meter is used to monitor the gas flow rate on the bypass pipe. Optionally, the flow meter is a vortex flow meter.
[0022] Furthermore, a vent pipe is provided on the bypass pipe, one end of which is welded to the bypass pipe, and the other end extends vertically upward with its top end higher than the top of the combustion furnace.
[0023] When the gas pressure in the bypass pipeline rises abnormally, the excess gas can be safely released through the vent pipe to prevent the pipeline from being damaged due to overpressure. When the system is started up, stopped, or under maintenance, the residual gas in the pipeline can be discharged through the vent pipe to prevent the gas from accumulating in the pipeline and causing safety hazards. The vent pipe is vertical and higher than the top of the furnace, which can prevent the released gas from directly contacting the high-temperature area of the combustion furnace or other equipment, reducing secondary safety risks.
[0024] Furthermore, it also includes a purging assembly, which consists of several groups, each group of which includes a shut-off valve and a quick-connect flexible connector.
[0025] Furthermore, the purging assembly is welded to the pipe sections upstream of the flow meter of the bypass pipeline, downstream of the regulating valve, and between the shut-off valve and the manual valve of the blast furnace gas main pipeline.
[0026] The three purging assemblies are installed in specific pipe sections. The purging assembly upstream of the flow meter is used to purge the upstream pipeline with an external air source during flow meter maintenance or blockage to remove coal dust or impurities and prevent contaminants from entering the flow meter and affecting measurement accuracy. The purging assembly downstream of the regulating valve can purge residual coal dust or gas in the downstream pipeline during regulating valve maintenance to prevent coal dust leakage or gas ignition hazards when disassembling the valve. The purging assembly between the shut-off valve and the manual valve is used to purge residual gas or coal dust in this section of the main pipeline after the shut-off valve is closed to ensure safety during main pipeline maintenance and prevent residual coal dust from becoming damp and caking in the pipeline, thus blocking the pipeline.
[0027] The above solution effectively solves the technical problems existing in the prior art. As an expandable implementation, it also includes a PLC controller. The flow meter signal output terminal is connected to the PLC's analog input module via a shielded twisted-pair cable, and the control signal input terminal of the regulating valve is connected to the PLC's analog output module via a shielded twisted-pair cable. The PLC outputs a 4-20mA analog signal corresponding to the 0-50mm stroke of the regulating valve stem, realizing continuous adjustment of the valve opening. The PLC is connected to the central control display screen of the blast furnace pulverized coal injection system via an industrial Ethernet, transmitting real-time flow data, valve opening, and system status to the central control terminal. Simultaneously, it receives the flow setpoint from the central control terminal, realizing a dual operation mode of on-site automatic control and remote monitoring and adjustment. The central control terminal sends the target flow value to the PLC, which stores this value as the setpoint SV. The vortex flow meter collects the actual gas flow in the bypass pipeline in real time, converts the 4-20mA analog signal into a digital signal, and transmits it to the PLC as the actual measured value PV. The PLC compares the setpoint SV with the actual measured value PV and calculates the deviation. The PLC calculates the deviation value using a built-in PID algorithm, and then outputs the control signal after PID calculation to the electric regulating ball valve, driving the valve stem to adjust the valve opening. Of course, the above-mentioned technologies are existing conventional technologies; PLC products from manufacturers such as Siemens and Schneider Electric already have analog input / output modules and PID control functions, and can be directly adapted to the flow control scenario targeted in this application.
[0028] During the construction process, blind flanges were first installed on the single blast furnace gas pipeline. After the blast furnace gas pipeline passed the purging and testing, Φ300 bypass pipelines were added on both sides of the Φ600 blast furnace gas pipeline shut-off valve, and Φ300 regulating valves were installed. Correspondingly, the valves, measuring points, vents, and purging points on the pipeline were reinstalled. The original shut-off valve was closed, allowing blast furnace gas to enter the combustion furnace through the bypass pipeline, with the gas flow controlled by the Φ300 regulating valve.
[0029] In practical application, the increased pulverized coal injection concentration in single-pipeline systems saves on gaseous medium consumption during the injection process and reduces blast furnace gas usage. Taking blast furnaces No. 6, No. 7, and the new No. 1 in the plant area as examples, the blast furnace gas usage has been reduced from the original 400-600 m³ / h. 3 / h reduced to 100~300m 3 / h, reduced by 300m 3 / h.
[0030] The mill hourly capacity of each medium-speed mill has increased from the original 0.5-0.8 tons to 1.2-1.5 tons, an increase of 0.7 tons per hour, which has accelerated the operating rate of the medium-speed pulverized coal mill and better achieved cost reduction and efficiency improvement.
[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.
Claims
1. A coke oven gas pipeline at the inlet of a blast furnace pulverized coal injection system, characterized in that, The system includes a blast furnace gas pipeline and a bypass pipeline. A shut-off valve is installed on the blast furnace gas pipeline, and a regulating valve is installed on the bypass pipeline. The shut-off valve is connected in series in the middle of the blast furnace gas pipeline. Both ends of the bypass pipeline are welded to the blast furnace gas pipelines on either side of the shut-off valve, and the welding points between the bypass pipeline and the blast furnace gas pipeline are located at the lowest point of the blast furnace gas pipeline. The diameter of the bypass pipeline is half the diameter of the blast furnace gas pipeline. A vent pipe is installed on the bypass pipeline, with one end welded to the bypass pipeline and the other end extending vertically upwards with its top end higher than the top of the combustion furnace. The system also includes several purging assemblies, each consisting of a shut-off valve and a quick-connect flexible joint. The purging assemblies are welded to the upstream section of the flow meter of the bypass pipeline, the downstream section of the regulating valve, and the section between the shut-off valve and the manual valve of the main blast furnace gas pipeline.
2. The coke oven gas pipeline at the combustion furnace inlet of the blast furnace pulverized coal injection system according to claim 1, characterized in that, The bypass pipe is made of seamless steel pipe.
3. The coke oven gas pipeline at the combustion furnace inlet of the blast furnace pulverized coal injection system according to claim 1, characterized in that, A flow meter is installed on the bypass pipe.