Control system and method for producing mixed gas by mixing blast furnace gas with coke oven gas

Abstract

The present invention relates to a control system and method for manufacturing mixed coal gas by mixing blast furnace gas with coke oven gas. The control system includes a blast furnace gas flow regulating valve arranged on a blast furnace gas pipeline and a coke oven gas flow regulating valve arranged on the coke oven gas pipeline; the blast furnace gas pipeline is also provided with a pressure recording alarm instrument 1 and a flow recording and regulating cumulative instrument; the coke oven gas pipeline is also provided with a pressure recording alarm instrument 2, a flow recording ratio regulating cumulative instrument and a pressure recording instrument 1; the blast furnace gas pipeline downstream of the blast furnace gas flow regulating valve and the coke oven gas pipeline downstream of the pressure recording instrument 1 are connected to the mixed gas pipeline, and the mixed gas pipeline is provided with a pressure recording instrument 2. The present invention can not only provide mixed coal gas with stable pressure and constant mixing ratio to downstream users, but also ensure the safety of the front-end coke oven gas pipeline and the blast furnace gas pipeline.

Description

Technical Field

[0001] The invention relates to the technical field of deep processing of coking products, and in particular to a control system and method for preparing mixed gas by mixing blast furnace gas with coke oven gas. Background Art

[0002] The coking products produced by the coking plant are mainly coal tar and crude benzene. In the deep processing of coal tar and crude benzene, various heating furnaces basically use coke oven gas as the heating fuel gas. Its main combustible components are hydrogen (about 58%) and methane (about 26%). It also contains a small amount of carbon monoxide (about 6%). The calorific value is about 4200 kcal / standard cubic meter, with high calorific value and stable combustion.

[0003] Blast furnace gas is a combustible gas produced as a by-product in the blast furnace iron-making process. Its main combustible components are hydrogen (about 2%) and carbon monoxide (about 26%), and it also contains a large amount of non-flammable carbon dioxide (about 18%) and nitrogen (about 54%). Its calorific value is only about 730 kcal / standard cubic meter, which is low and not easy to burn stably.

[0004] Blast furnace gas is a by-product gas of steel plants. If it can be fully utilized, it can not only reduce the energy consumption of enterprises, but also improve the pollution of the surrounding environment by steel enterprises. Since blast furnace gas contains a large amount of carbon dioxide and nitrogen, it will absorb a large amount of heat generated during the combustion process, reducing the intensity of the oxidation reaction of the combustible gas, which is manifested in slow combustion speed and unstable combustion on a macro scale. In order to effectively utilize blast furnace gas, a by-product gas, it is necessary to mix a certain proportion of coke oven gas to increase the calorific value of the mixed gas, increase the intensity of combustion, and achieve the purpose of stable combustion.

[0005] Since there are multiple processing devices for the deep processing of coal tar and crude benzene in the coking plant, and each processing device contains many processing units, it is not possible to design a process facility for producing mixed gas by mixing blast furnace gas with coke oven gas for each heating furnace. It is necessary to set up a process facility for producing mixed gas by mixing blast furnace gas with coke oven gas in the external blast furnace gas main. This can both simplify the design and save costs.

[0006] Since both coke oven gas and blast furnace gas are explosive gases, their compositions are different and their explosion limits range greatly vary. The explosion limit of coke oven gas is 4.72% to 37.54%, and the explosion limit of blast furnace gas is 40% to 70%. The process facilities for mixing blast furnace gas with coke oven gas to produce mixed gas (hereinafter referred to as "blending facilities") must not only be able to provide mixed gas with stable pressure and constant blending ratio, but also ensure the safety of the front-end coke oven gas pipeline and blast furnace gas pipeline, that is, the gas in the pipeline cannot flow back to prevent danger to the upstream pipeline.

[0007] In summary, the design of blending facilities is a crucial process link for realizing blast furnace gas as heating fuel gas for deep processing of coking products in coking plants. Summary of the invention

[0008] The present invention provides a control system and method for preparing mixed gas by mixing blast furnace gas with coke oven gas, which can not only provide mixed gas with stable pressure and constant mixing ratio to downstream users, but also ensure the safety of the front-end coke oven gas pipeline and blast furnace gas pipeline.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A control system for preparing mixed gas by mixing blast furnace gas with coke oven gas, comprising a blast furnace gas flow regulating valve arranged on a blast furnace gas pipeline and a coke oven gas flow regulating valve arranged on a coke oven gas pipeline; a pressure recording alarm instrument 1 and a flow recording regulation accumulating instrument are sequentially arranged on the blast furnace gas pipeline upstream of the blast furnace gas flow regulating valve along the flow direction of the blast furnace gas; a pressure recording alarm instrument 2 and a flow recording proportion regulation accumulating instrument are sequentially arranged on the coke oven gas pipeline upstream of the coke oven gas flow regulating valve along the flow direction of the coke oven gas; a pressure recording instrument 1 is arranged on the coke oven gas pipeline downstream of the coke oven gas flow regulating valve; the blast furnace gas pipeline downstream of the blast furnace gas flow regulating valve and the pressure recording instrument 1 are connected to each other The downstream coke oven gas pipeline is connected to the mixed gas pipeline, and the mixed gas pipeline is provided with a pressure recording instrument 2; the pressure recording alarm instrument 1 and the pressure recording instrument 2 are respectively connected to the pressure difference recording interlocking alarm instrument 1; the pressure recording alarm instrument 2 and the pressure recording instrument 1 are respectively connected to the pressure difference recording interlocking alarm instrument 2; the flow recording and regulating cumulative instrument is connected to the flow recording proportion regulating cumulative instrument and the pressure recording instrument 2; the blast furnace gas flow regulating valve is interlocked and controlled with the pressure difference recording interlocking alarm instrument 1, the flow recording regulating cumulative instrument and the coke oven gas flow regulating valve; the coke oven gas flow regulating valve is also interlocked and controlled with the flow recording proportion regulating cumulative instrument and the pressure difference recording interlocking alarm instrument 2.

[0011] The invention discloses a control method for manufacturing mixed gas by mixing blast furnace gas with coke oven gas. The method controls the gas supply pressure of the mixed gas by adjusting the blast furnace gas flow rate to ensure a stable gas source for users of the mixed gas; controls the amount of coke oven gas mixed into the blast furnace gas by proportional regulation to obtain a mixed gas with a stable mixing ratio; interlocks the coke oven gas flow regulating valve and the blast furnace gas flow regulating valve with a pressure difference recording interlock alarm instrument to achieve emergency cutoff to prevent gas backflow in the pipeline; monitors the pressure of the coke oven gas pipeline and the blast furnace gas pipeline, and adopts low pressure alarm and ultra-low pressure emergency cutoff to prevent the danger of gas backflow in the pipeline.

[0012] The low pressure alarm means that when the pressure difference measured by the pressure differential recording interlock alarm instrument 1 is 0.5kPa, an alarm is issued through the pressure recording alarm instrument 1, and when the pressure difference measured by the pressure differential recording interlock alarm instrument 2 is 0.5kPa, an alarm is issued through the pressure recording alarm instrument 2; the ultra-low pressure emergency cut-off means that when the pressure difference measured by the pressure differential recording interlock alarm instrument 1 is less than zero, the blast furnace gas flow regulating valve and the coke oven gas flow regulating valve are urgently cut off, and when the pressure difference measured by the pressure differential recording interlock alarm instrument 2 is less than zero, the coke oven gas flow regulating valve is urgently cut off.

[0013] When the pressure value measured by the pressure recording alarm instrument 1 is 2kPa, the alarm starts, and when the pressure value measured by the pressure recording alarm instrument 1 is 1.5kPa, the blast furnace gas flow regulating valve and the coke oven gas flow regulating valve are urgently cut off.

[0014] When the pressure value measured by the pressure recording alarm instrument 2 is 2kPa, the alarm starts, and when the pressure value measured by the pressure recording alarm instrument 2 is 1.5kPa, the coke oven gas flow regulating valve is urgently cut off.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1) Control the supply pressure of the mixed gas by adjusting the blast furnace gas flow rate to ensure the stability of the gas source required by subsequent users of the mixed gas;

[0017] 2) Control the amount of blast furnace gas mixed with coke oven gas by proportional regulation to obtain a mixed gas with a stable blending ratio;

[0018] 3) The gas pressure in the upstream and downstream pipelines of the coke oven gas flow regulating valve and the gas pressure in the upstream and downstream pipelines of the blast furnace gas flow regulating valve are monitored by pressure difference recording interlock alarm instruments, and emergency cut-off is achieved through interlock control to prevent the upstream pipeline from being in danger due to gas backflow in the pipeline;

[0019] 4) The gas sources in the coke oven gas pipeline and blast furnace gas pipeline are pressure-monitored respectively, and low-pressure alarm and ultra-low-pressure emergency cut-off are used to prevent the harm caused by gas backflow in the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a control system for preparing mixed gas by mixing blast furnace gas with coke oven gas according to the present invention.

[0021] In the figure: 1. Blast furnace gas flow control valve 2. Coke oven gas flow control valve FRCQ01. Flow recording and regulating cumulative instrument FFRCQ02. Flow recording and proportional regulating cumulative instrument PRA01. Pressure recording and alarm instrument 1 PRA03. Pressure recording and alarm instrument 2 PR04. Pressure recording instrument 1 PR02. Pressure recording instrument 2 PdRSA01. Pressure difference recording interlocking alarm instrument 1 PdRSA02. Pressure difference recording interlocking alarm instrument 2 L low limit LL ultra low limit DETAILED DESCRIPTION

[0022] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0023] like Figure 1 As shown, the control system for preparing mixed gas by mixing blast furnace gas with coke oven gas in the present invention comprises a blast furnace gas flow regulating valve 1 arranged on the blast furnace gas pipeline and a coke oven gas flow regulating valve 2 arranged on the coke oven gas pipeline; a pressure recording alarm instrument PRA01 and a flow recording and regulating cumulative instrument FRCQ01 are sequentially arranged on the blast furnace gas pipeline upstream of the blast furnace gas flow regulating valve 1 along the flow direction of the blast furnace gas; a pressure recording alarm instrument PRA03 and a flow recording proportional regulation cumulative instrument FFRCQ02 are sequentially arranged on the coke oven gas pipeline upstream of the coke oven gas flow regulating valve 2 along the flow direction of the coke oven gas; a pressure recording instrument PR04 is arranged on the coke oven gas pipeline downstream of the coke oven gas flow regulating valve 2; the blast furnace gas pipeline downstream of the blast furnace gas flow regulating valve 1 and the coke oven gas pipeline downstream of the pressure recording instrument PR04 are connected to the mixed gas pipeline, A pressure recording instrument 2 PR02 is arranged on the mixed gas pipeline; the pressure recording alarm instrument 1 PRA01 and the pressure recording instrument 2 PR02 are respectively connected to a pressure differential recording interlocking alarm instrument 1 PdRSA01; the pressure recording alarm instrument 2 PRA03 and the pressure recording instrument 1 PR04 are respectively connected to a pressure differential recording interlocking alarm instrument 2 PdRSA02; the flow recording and regulating cumulative instrument FRCQ01 is connected to a flow recording proportional regulating cumulative instrument FFRCQ02 and a pressure recording instrument 2 PR02; the blast furnace gas flow regulating valve 1 is interlocked and controlled with a pressure differential recording interlocking alarm instrument 1 PdRSA01, a flow recording and regulating cumulative instrument FRCQ01 and a coke oven gas flow regulating valve 2; the coke oven gas flow regulating valve 2 is also interlocked and controlled with a flow recording proportional regulating cumulative instrument FFRCQ02 and a pressure differential recording interlocking alarm instrument 2 PdRSA02.

[0024] The control method for preparing mixed coal gas by mixing blast furnace gas with coke oven gas described in the present invention controls the gas supply pressure of the mixed coal gas by adjusting the blast furnace gas flow rate to ensure a stable gas source for users of the mixed coal gas; controls the amount of coke oven gas mixed into the blast furnace gas by proportional regulation to obtain a mixed coal gas with a stable blending ratio; interlocks the coke oven gas flow regulating valve 2 and the blast furnace gas flow regulating valve 1 with the pressure difference recording interlocking alarm instruments PdRSA01 and PdRSA02 to achieve emergency shutoff to prevent gas backflow in the pipeline; monitors the pressure of the coke oven gas pipeline and the blast furnace gas pipeline, and adopts low pressure alarm and ultra-low pressure emergency shutoff to prevent the danger of gas backflow in the pipeline.

[0025] The low pressure alarm refers to the alarm through the pressure recording alarm instrument PRA01 when the pressure difference measured by the pressure differential recording interlock alarm instrument PdRSA01 is 0.5kPa, and the alarm through the pressure recording alarm instrument PRA03 when the pressure difference measured by the pressure differential recording interlock alarm instrument PdRSA02 is 0.5kPa; the ultra-low pressure emergency cut-off refers to the emergency cut-off of blast furnace gas flow regulating valve 1 and coke oven gas flow regulating valve 2 when the pressure difference measured by the pressure differential recording interlock alarm instrument PdRSA01 is less than zero, and the emergency cut-off of coke oven gas flow regulating valve 2 when the pressure difference measured by the pressure differential recording interlock alarm instrument PdRSA02 is less than zero.

[0026] When the pressure value measured by the pressure recording alarm instrument PRA01 is 2kPa, the alarm starts. When the pressure value measured by the pressure recording alarm instrument PRA01 is 1.5kPa, the blast furnace gas flow regulating valve 1 and the coke oven gas flow regulating valve 2 are urgently cut off.

[0027] When the pressure value measured by the pressure recording alarm instrument PRA02 is 2kPa, the alarm starts, and when the pressure value measured by the pressure recording alarm instrument PRA02 is 1.5kPa, the coke oven gas flow regulating valve is urgently cut off.

[0028] The present invention is applied to the process facilities for manufacturing mixed coal gas by blending blast furnace gas and coal gas, which are centrally set up in the blast furnace gas main. Blast furnace gas is the main gas supply source, with a large gas flow rate and a thick pipeline diameter; while coke oven gas has a relatively small gas flow rate and a thin pipeline diameter. Therefore, the blending facility is designed around the blast furnace gas pipeline. The design principle of the present invention is to control blast furnace gas as the main method and coke oven gas as the auxiliary method. Since the gas supply pressures of the two gases are basically the same (both are about 5kPa), there is no need to set a pressure reducing device for the blending facility.

[0029] First, the flow of blast furnace gas is adjusted by blast furnace gas flow control valve 1, and the pressure of the mixed gas is controlled by the flow recorded and adjusted by the cumulative instrument FRCQ01. The gas supply pressure of the mixed gas is displayed by the pressure recording instrument 2 PR02. This is the most important automatic control process of the blending facility, and all other control methods are carried out around this main control process.

[0030] Second, through the coke oven gas flow control valve 2, the flow displayed by the cumulative instrument FRCQ01 is adjusted according to the flow record, and the flow of coke oven gas mixed into the blast furnace gas is adjusted proportionally (for example, 1:9). The flow displayed by the cumulative instrument FFRCQ02 is adjusted by the flow record ratio to control the mixing ratio of the mixed gas. This is an important means to stabilize the composition of the mixed gas.

[0031] Third, on the blast furnace gas pipeline, a pressure recording alarm instrument PRA01 is installed upstream of the blast furnace gas flow regulating valve 1; a pressure recording instrument 2 PR02 is installed on the mixed gas pipeline, and interlocking control is performed through a pressure difference recording interlocking alarm instrument 1 PdRSA01; if the pressure difference is less than zero, it means that the gas in the pipeline is reversely flowing, and coke oven gas is reversely flowing into the blast furnace gas pipeline; set an alarm when the pressure difference approaches the low pressure lower limit L=0.5kPa, and if the pressure difference reaches the ultra-low limit LL less than zero, the blast furnace gas flow regulating valve 1 and the coke oven gas flow regulating valve 2 are urgently cut off to ensure the safety of the pipeline.

[0032] Fourth, the pressure recording alarm instrument PRA01 installed upstream of the blast furnace gas flow regulating valve 1 on the blast furnace gas pipeline is set to display that when the pressure approaches the lower limit L=2kPa, the pressure recording alarm instrument PRA01 starts to alarm. If the pressure approaches the ultra-low limit LL=1.5kPa, it can no longer meet the normal operation of the blending facility, that is, it cannot provide a reliable mixed gas pressure for subsequent users, which is equivalent to the ultra-low limit LL of the pressure difference recording interlock alarm instrument PdRSA01 being less than zero. At this time, the blast furnace gas flow regulating valve 1 and the coke oven gas flow regulating valve 2 are urgently cut off to ensure the safety of the pipeline.

[0033] Fifth, the pressure recording alarm instrument 2 PRA03 and the pressure recording alarm instrument 1 PR04 are respectively set at the upstream and downstream of the coke oven gas flow regulating valve 2 on the coke oven gas pipeline, and interlocking control is performed through the pressure difference recording interlocking alarm instrument 2 PdRSA02; if the pressure difference is less than zero, it means that the gas in the pipeline is reversed, that is, blast furnace gas is reversed into the coke oven gas pipeline, and the alarm is set when the pressure difference approaches the lower limit L=0.5kPa. If the pressure difference reaches the ultra-low limit LL less than zero, the coke oven gas flow regulating valve 2 is urgently cut off to ensure the safety of the pipeline. At this time, if the blast furnace gas pipeline is working normally, the blending facility can still maintain operation, but the gas provided by the blending facility is blast furnace gas instead of mixed gas, which can maintain short-term production; since the alarm has been issued, the subsequent operation will be determined according to the situation.

[0034] Sixth, the pressure recording alarm instrument PRA03 installed upstream of the coke oven gas flow regulating valve 2 on the coke oven gas pipeline starts to alarm when the set pressure approaches the lower limit L=2kPa. If the pressure approaches the ultra-low limit LL=1.5kPa, it can no longer meet the normal operation of the mixing facility, which is equivalent to the ultra-low limit LL of the pressure difference recording interlock alarm instrument PdRSA02 being less than zero. At this time, the coke oven gas flow regulating valve 2 is urgently cut off to ensure the safety of the pipeline.

[0035] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A control method for preparing mixed gas by mixing blast furnace gas with coke oven gas, characterized in that: The invention is based on a control system for manufacturing mixed coal gas by mixing blast furnace gas with coke oven gas; the control system for manufacturing mixed coal gas by mixing blast furnace gas with coke oven gas comprises a blast furnace gas flow regulating valve arranged on the blast furnace gas pipeline and a coke oven gas flow regulating valve arranged on the coke oven gas pipeline; a pressure recording alarm instrument 1 and a flow recording and regulating cumulative instrument are sequentially arranged on the blast furnace gas pipeline upstream of the blast furnace gas flow regulating valve along the flow direction of the blast furnace gas; a pressure recording alarm instrument 2 and a flow recording and proportional regulating cumulative instrument are sequentially arranged on the coke oven gas pipeline upstream of the coke oven gas flow regulating valve along the flow direction of the coke oven gas; a pressure recording instrument 1 is arranged on the coke oven gas pipeline downstream of the coke oven gas flow regulating valve; The blast furnace gas pipeline and the coke oven gas pipeline downstream of the pressure recording instrument 1 are connected to the mixed gas pipeline, and the mixed gas pipeline is provided with a pressure recording instrument 2; the pressure recording alarm instrument 1 and the pressure recording instrument 2 are respectively connected to the pressure difference recording interlocking alarm instrument 1; the pressure recording alarm instrument 2 and the pressure recording instrument 1 are respectively connected to the pressure difference recording interlocking alarm instrument 2; the flow recording and regulating cumulative instrument is connected to the flow recording proportion regulating cumulative instrument and the pressure recording instrument 2; the blast furnace gas flow regulating valve is interlocked and controlled with the pressure difference recording interlocking alarm instrument 1, the flow recording regulating cumulative instrument and the coke oven gas flow regulating valve; the coke oven gas flow regulating valve is also interlocked and controlled with the flow recording proportion regulating cumulative instrument and the pressure difference recording interlocking alarm instrument 2; The control method for manufacturing mixed gas by mixing blast furnace gas with coke oven gas includes: controlling the gas supply pressure of the mixed gas by adjusting the blast furnace gas flow rate to ensure a stable gas source for users of the mixed gas; controlling the amount of coke oven gas mixed into the blast furnace gas by proportional regulation to obtain a mixed gas with a stable mixing ratio; interlocking the coke oven gas flow regulating valve and the blast furnace gas flow regulating valve with a pressure difference recording interlocking alarm instrument to achieve emergency cutoff to prevent gas backflow in the pipeline; monitoring the pressure of the coke oven gas pipeline and the blast furnace gas pipeline, and adopting low pressure alarm and ultra-low pressure emergency cutoff to prevent the danger of gas backflow in the pipeline; The low pressure alarm means that when the pressure difference measured by the pressure differential recording interlock alarm instrument 1 is 0.5kPa, an alarm is issued through the pressure recording alarm instrument 1, and when the pressure difference measured by the pressure differential recording interlock alarm instrument 2 is 0.5kPa, an alarm is issued through the pressure recording alarm instrument 2; the ultra-low pressure emergency cut-off means that when the pressure difference measured by the pressure differential recording interlock alarm instrument 1 is less than zero, the blast furnace gas flow regulating valve and the coke oven gas flow regulating valve are urgently cut off, and when the pressure difference measured by the pressure differential recording interlock alarm instrument 2 is less than zero, the coke oven gas flow regulating valve is urgently cut off; When the pressure value measured by the pressure recording alarm instrument 1 is 2 kPa, the alarm starts; when the pressure value measured by the pressure recording alarm instrument 1 is 1.5 kPa, the blast furnace gas flow regulating valve and the coke oven gas flow regulating valve are urgently cut off; When the pressure value measured by the pressure recording alarm instrument 2 is 2kPa, the alarm starts, and when the pressure value measured by the pressure recording alarm instrument 2 is 1.5kPa, the coke oven gas flow regulating valve is urgently cut off.

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