Coke oven gas injection system for blast furnace and injection process of coke oven gas injection system

Abstract

The invention discloses a blast furnace coke oven gas injection system and an injection process thereof. The blast furnace coke oven gas injection system comprises a T-shaped filter, a compressor, a coke oven gas cooler, a gas-liquid separator, a gas main pipe, a gas valve station and a gas branch pipe, an inlet of the T-shaped filter is communicated with a coke oven gas pipe network through a pipeline and carries out dust filtration on coke oven gas, and an outlet of the T-shaped filter is communicated with an inlet of the gas-liquid separator through a silencer I, a compressor, a silencer II, a check valve I and a coke oven gas cooler in sequence through a pipeline. The filtered coke oven gas is sequentially subjected to noise reduction, pressurization and cooling and then is fed into a gas-liquid separator for gas-liquid separation; a gas outlet of the gas-liquid separator is communicated with a gas inlet of the gas valve station through a gas header pipe by virtue of a pipeline, a plurality of gas branch pipes are led out from a gas outlet of the gas valve station, and the gas outlet of the gas valve station is respectively communicated with corresponding blast-furnace tuyeres by virtue of the gas branch pipes, so that coke oven gas is injected into the corresponding blast-furnace tuyeres. The invention can realize automatic safety control of coke oven gas injection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of blast furnace ironmaking, and particularly relates to a blast furnace injection of coke oven gas system and an injection process thereof. BACKGROUND

[0002] Blast furnace ironmaking is the most important ironmaking process in modern steel enterprises, and its principle is to reduce liquid pig iron by chemical reaction and combustion of coke and injected fuel in a blast furnace with iron ore, coke and flux. However, this process is also the most energy-consuming and carbon-emitting link in the entire steel production process, accounting for about 60-70% of the total energy consumption of the enterprise, and the carbon emission proportion is extremely high. Under the background of global active response to climate change and the strategic goal of "carbon peak and carbon neutralization", how to effectively reduce the carbon consumption and carbon emission of blast furnace ironmaking has become a major technical problem to be solved in the steel industry.

[0003] Traditional blast furnace ironmaking mainly relies on metallurgical coke as a reducing agent and heat source. In order to reduce production costs and dependence on coke, various injection of auxiliary fuel technologies have been developed, such as injection of pulverized coal (PCI), heavy oil, natural gas, etc. Among them, the injection of pulverized coal technology is the most mature and popular, which has reduced the coke ratio (i.e. the amount of coke consumed per ton of molten iron) to some extent. However, coal itself is still a carbon-containing fuel, and its combustion will still produce a large amount of CO2, and the preparation and injection system of coal powder is complex and has certain safety risks.

[0004] Coke oven gas (COG) is a byproduct produced during the production of coke, and its main components are 55-60% H2, 23-27% CH4, 5-8% CO, and a small amount of nitrogen, carbon dioxide, etc. Its heat value is about 17-19 MJ / Nm³, and it is a hydrogen-rich gas. In the traditional energy balance of steel enterprises, coke oven gas is used for heating furnaces, power generation or as chemical raw materials, in addition to being partially returned to the coke oven for heating. However, these utilization methods or energy utilization efficiency need to be improved, or they cannot fundamentally solve the problem of carbon emission reduction of blast furnaces.

[0005] Injecting hydrogen-rich coke oven gas into a blast furnace to replace part of the coke and coal powder is considered as a very promising low-carbon smelting path for blast furnaces. Hydrogen as a reducing agent has a higher reduction efficiency than carbon monoxide, and the reduction product is water, without CO2 generation. Therefore, blast furnace injection of coke oven gas can theoretically significantly reduce coke ratio and carbon emissions, while improving smelting efficiency.

[0006] At present, there have been some research, experiments and industrial practices around the technology of blast furnace injection of coke oven gas, but this technology still faces a series of technical challenges and limitations and has not been widely applied. The existing technology of blast furnace injection of coke oven gas mainly has the following problems: (1) Injection process and system adaptability problem: The existing blast furnace injection system is mainly designed for pulverized coal, while coke oven gas as a gaseous fuel, its storage, transportation, metering and injection mode are fundamentally different from solid pulverized coal; if the existing pulverized coal injection system is directly used or simply modified, there are safety and efficiency hidden dangers such as gas leakage, pressure fluctuation, and uneven mixing with pulverized coal.

[0007] (2) Influence on the stability of blast furnace operation: The blast furnace is a complex heat balance and material balance system, and a large amount of hydrogen-rich cold gas (coke oven gas usually without preheating or limited preheating temperature) injection will significantly change the temperature distribution in the furnace, especially lower the theoretical combustion temperature (TFT), which may lead to insufficient heat in the hearth, fluctuation of furnace condition, and even furnace cooling accident. Although the existing technology adjusts the hot blast temperature, oxygen enrichment rate and other parameters through experience to compensate, but still lacks a set of scientific and accurate operation system to optimize the injection amount, oxygen enrichment amount, hot blast temperature and other key parameters to ensure the long-term stable operation of the blast furnace.

[0008] (3) Gas utilization rate in the furnace: Hydrogen has low density and low viscosity, and its upward speed in the furnace is fast, which may lead to a short contact reaction time with iron ore, and the hydrogen gas leaves the reaction zone with the upward gas flow without fully participating in the reduction reaction, resulting in chemical energy waste.

[0009] (4) Safety and monitoring technology: Coke oven gas mixed with air is explosive, so the safety during transportation and injection is crucial. However, the integration and reliability of key safety facilities such as safety interlocking, leakage monitoring and emergency shutdown of the existing technology for injection system still need to be improved to ensure absolute safety in complex industrial environment.

[0010] (5) System energy efficiency and economy: The existing technology only considers simply injecting coke oven gas into the blast furnace, but fails to optimize from the perspective of the whole plant energy system. For example, it does not consider the impact of coke oven gas injection on the yield and quality of secondary energy sources such as blast furnace gas (BFG) and converter gas (LDG), as well as the change of the whole plant gas balance, which may affect the stable supply of power plant and other users, thereby affecting the overall energy efficiency and economy.

[0011] In summary, although the blast furnace injection of coke oven gas technology has significant energy-saving and emission-reducing advantages in concept, the existing technology still has obvious defects in system integration, process stability, reduction efficiency, safety control and whole plant energy efficiency coordination, which restricts the large-scale industrial application of this technology. Therefore, how to develop a safe and systematic blast furnace coke oven gas injection system and technology has become a difficult problem to be solved. SUMMARY

[0012] The technical problem solved by the present application is to provide a blast furnace coke oven gas injection system and an injection process, which can realize automatic and safe control of coke oven gas injection, and has significant improvement in system integration, process stability, reduction efficiency, safety control, carbon reduction and efficiency increase, and realizes large-scale industrial application.

[0013] To solve the above technical problems, the present application adopts the following technical scheme: the blast furnace coke oven gas injection system comprises a T-shaped filter, a silencer I, a compressor, a silencer II, a check valve I, a coke oven gas cooler, a gas-liquid separator, a gas main pipe, a gas valve station and a gas branch pipe; the inlet of the T-shaped filter is connected with a coke oven gas pipe network through a pipeline, and the coke oven gas is subjected to dust filtration treatment; the outlet of the T-shaped filter is connected with the inlet of the gas-liquid separator through a pipeline in sequence via the silencer I, the compressor, the silencer II, the check valve I and the coke oven gas cooler, and the filtered coke oven gas is subjected to silencing, pressurizing and cooling in sequence and then sent to the gas-liquid separator for gas-liquid separation treatment; the gas outlet of the gas-liquid separator is connected with the gas inlet of the gas valve station through a pipeline via the gas main pipe, and the gas outlet of the gas valve station leads to a plurality of gas branch pipes which are connected with corresponding blast furnace tuyeres in sequence via the gas branch pipes, so that the coke oven gas after gas-liquid separation is injected into the corresponding blast furnace tuyeres.

[0014] Preferably, the system further comprises an electric butterfly valve I and an electric flap valve I; the electric butterfly valve I and the electric flap valve I are arranged on the pipeline between the T-shaped filter and the coke oven gas pipe network in sequence and are connected with each other at intervals, and the electric flap valve I is arranged on the side close to the T-shaped filter, so that the electric butterfly valve I and the electric flap valve I are used to control the on-off of the coke oven gas sent to the T-shaped filter.

[0015] Preferably, the system further comprises a check valve II, an outlet flow regulating valve, an electric flap valve II, an electric butterfly valve II, an outlet gas flap valve and a pneumatic flow regulating valve which are arranged on the gas main pipe in sequence and are connected with each other at intervals, and the pneumatic flow regulating valve is arranged on the side close to the gas valve station, so that the check valve II is used to prevent the coke oven gas from flowing back, the electric butterfly valve II and the electric flap valve II are used to control the on-off of the coke oven gas sent to the gas valve station, and the outlet flow regulating valve and the pneumatic flow regulating valve are used to regulate the flow of the coke oven gas sent to the gas valve station; the number of the gas branch pipes is consistent with the number of the blast furnace tuyeres, and a cut-off valve I for controlling the on-off of each gas branch pipe is arranged on each gas branch pipe.

[0016] Preferably, it further comprises a nitrogen tank, a nitrogen switch valve and a nitrogen branch pipe; the nitrogen tank is communicated with the gas valve station through a pipeline via the nitrogen switch valve and a gas supplement port, and each nitrogen branch pipe is further communicated with the gas valve station at the other end of the corresponding gas branch pipe relative to the section between the cut-off valve I and the corresponding blast furnace tuyere; and each nitrogen branch pipe is further communicated with the gas valve station at the other end of the corresponding gas branch pipe, and a cut-off valve II is further arranged on each nitrogen branch pipe to control the opening and closing thereof, thereby introducing nitrogen into the corresponding blast furnace tuyere and controlling the opening and closing of the nitrogen introduced into the gas valve station via the nitrogen switch valve.

[0017] Preferably, it further comprises a circulating backflow regulating valve, an emergency return valve and a diffusing electric ball valve; one end of the circulating backflow regulating valve is communicated with the gas outlet of the gas-liquid separator via a pipeline, and the other end thereof is communicated with the inlet of the T-shaped filter via a pipeline, thereby returning the excess coke oven gas in the gas-liquid separator to the T-shaped filter via the circulating backflow regulating valve; one end of the emergency return valve is communicated with the outlet end of the check valve I, and the other end thereof is communicated with the inlet of the T-shaped filter via a pipeline, thereby returning the coke oven gas after being silenced and pressurized to the T-shaped filter via the emergency return valve when the circulating backflow regulating valve cannot be passed in time; one end of the diffusing electric ball valve is communicated with the pipeline between the electric flap valve I and the T-shaped filter via a pipeline, and the other end thereof is communicated with the outside world via a pipeline, thereby diffusing the coke oven gas via the diffusing electric ball valve when the pressure of the coke oven gas in the pipeline is greater than or equal to 20 KPa.

[0018] Preferably, it further comprises a soft water tank and a liquid supplement valve; one end of the liquid supplement valve is communicated with the inlet of the compressor via a pipeline, and the other end thereof is communicated with the soft water tank via a pipeline, thereby supplementing the liquid when the liquid level of the gas-liquid separator is less than or equal to 700 mm.

[0019] Preferably, it further comprises a liquid injection regulating valve, a liquid injection filter and a liquid discharge switch valve; the inlet of the liquid injection filter is communicated with the water outlet of the gas-liquid separator via a pipeline, and the outlet thereof is communicated with the inlet of the compressor via a pipeline via the liquid injection regulating valve, thereby circulating the water separated from the gas-liquid separator to the compressor after being filtered; one end of the liquid discharge switch valve is communicated with the liquid discharge port of the gas-liquid separator via a pipeline, and the other end thereof is communicated with the outside world via a pipeline, thereby discharging the excess water when the liquid level of the gas-liquid separator is greater than or equal to 1500 mm.

[0020] The blast furnace coke oven gas injection system of the present application comprises the following steps: (1) Before normal start-up, the liquid supplement valve is opened, and the liquid supplement valve is used to continuously supplement the liquid in the gas-liquid separator when the liquid level of the gas-liquid separator is less than or equal to 700 mm, and the opening degree of the circulating backflow regulating valve is adjusted to 100%; (2) Then open the electric butterfly valve I, electric flap valve I, electric flap valve II, electric butterfly valve II, outlet gas plug valve and liquid injection regulating valve, and close the emergency circuit valve and dispersion electric ball valve; (3) Then normally start, at this time the coke oven gas from the coke oven gas network first sent to the T filter for dust filtration, filtered coke oven gas after the noise eliminator I to eliminate noise after sending to the compressor to 0.55~0.7Mpa, then the pressurized coke oven gas after the noise eliminator II to eliminate noise after sending to the coke oven gas cooler for cooling, the moisture in the coke oven gas is separated out; (4) Then the cooled coke oven gas is sent to the gas-liquid separator for further gas-liquid separation treatment, at this time the separated coke oven gas is adjusted by the double cooperation of the outlet flow regulating valve and the pneumatic flow regulating valve, and then sent to the gas valve station through the gas main, and then injected into the corresponding blast furnace tuyere through the gas branch pipe, and the circulating backflow regulating valve is gradually adjusted in the process until the opening of the circulating backflow regulating valve is 0%. At the same time, the separated water is filtered by the liquid injection filter and first sent to the compressor for heat exchange and cooling of the coke oven gas in the compressor, and then sent to the coke oven gas cooler, and forms a reciprocating cycle. (5) When the blast furnace does not accept the injection of coke oven gas due to an emergency, close the check valve II and open the circulating backflow regulating valve, at this time the excess coke oven gas in the gas-liquid separator is returned to the T filter through the circulating backflow regulating valve; in this process, if the circulating backflow regulating valve cannot pass in time, open the emergency circuit valve and return the coke oven gas after noise elimination and pressurization to the T filter through the emergency circuit valve; (6) When the pressure of the coke oven gas in the pipeline is ≥20Kpa, open the dispersion electric ball valve and disperse the coke oven gas through the dispersion electric ball valve; (7) When it is necessary to stop and overhaul, close the electric butterfly valve I, electric flap valve I, electric flap valve II, electric butterfly valve II and outlet gas plug valve, open the circulating backflow regulating valve and nitrogen switch valve, and delay the liquid injection regulating valve for 20s to close, at this time nitrogen is injected into the corresponding blast furnace tuyere through the nitrogen branch pipe, thereby purging the blast furnace.

[0021] Preferably, the initial opening of the liquid injection regulating valve is 100%, and the opening value is gradually reduced according to the exhaust temperature requirement, and the opening of the liquid injection regulating valve is ensured to be not less than 50%.

[0022] Preferably, when the liquid injection pressure is ≥0.2Mpa and the gas-liquid separator liquid level is ≥900mm, the liquid supplement valve is automatically closed; when the gas-liquid separator liquid level is ≥1500mm, the liquid discharge switch valve is opened, and the excess water is discharged through the liquid discharge switch valve to realize dynamic balance control.

[0023] The beneficial effects of the present application are as follows: (1) The present application can realize automatic and safe control of coke oven gas injection, and has significant improvement in system integration, process stability, reduction efficiency, safety control, carbon reduction and efficiency increase, etc., and realizes large-scale industrial application. (2) The present application not only can ensure normal and stable operation of coke oven gas injection, but also can quickly implement emergency safety protection measures when an emergency occurs or maintenance is needed, so as to realize the goal of safe and efficient smelting. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0025] Figure 1 The present application is a structure diagram of a blast furnace coke oven gas injection system.

[0026] Among them, 1-coke oven gas pipe network; 2-electric butterfly valve I; 3-electric flap valve I; 4-T type filter; 5-silencer I; 6-compressor; 7-silencer II; 8-check valve I; 9-coke oven gas cooler; 10-gas-liquid separator; 11-check valve II; 12-outlet flow regulating valve; 13-electric flap valve II; 14-electric butterfly valve II; 15-outlet gas plug valve; 16-pneumatic flow regulating valve; 17-nitrogen gas package; 18-nitrogen gas on-off valve; 19-gas valve station; 20-blast furnace tuyere; 21-circulation backflow regulating valve; 22-emergency return valve; 23-dissipation electric ball valve; 24-soft water tank; 25-liquid supplement valve; 26-liquid injection regulating valve; 27-liquid injection filter; 28-liquid discharge on-off valve; 29-gas branch pipe; 30-nitrogen gas branch pipe. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described clearly and completely in the following specific embodiments.

[0028] The present application is a blast furnace coke oven gas injection system, which comprises a T type filter 4, a silencer I 5, a compressor 6, a silencer II 7, a check valve I 8, a coke oven gas cooler 9, a gas-liquid separator 10, a gas main pipe, a gas valve station 19 and a gas branch pipe 29; the specific structure is as follows: Figure 1As shown, the inlet of the T-shaped filter 4 is communicated with the coke oven gas pipe network 1 through a pipeline, and the coke oven gas is subjected to dust filtering treatment, the outlet of the T-shaped filter 4 is communicated with the inlet of the silencer I 5, the compressor 6, the silencer II 7, the check valve I 8, the coke oven gas cooler 9 and the gas-liquid separator 10 in sequence through a pipeline, and the filtered coke oven gas is sent into the gas-liquid separator 10 after being subjected to silencing, pressurizing and cooling in sequence; the gas outlet of the gas-liquid separator 10 is communicated with the gas inlet of the gas valve station 19 through a pipeline, the gas outlet of the gas valve station 19 leads out a plurality of gas branch pipes 29, and the gas branch pipes 29 are communicated with the corresponding blast furnace tuyeres 20 respectively, so that the coke oven gas after gas-liquid separation is injected into the corresponding blast furnace tuyeres 20. The cooperation of the silencer I 5 and the silencer II 7 can eliminate noise and reduce vibration, so as to protect the on-site equipment and improve the on-site working environment.

[0029] As shown in the figure, Figure 1 The electric butterfly valve I 2 and the electric flap valve I 3 are arranged on the pipeline between the T-shaped filter 4 and the coke oven gas pipe network 1 in sequence and are communicated at intervals, and the electric flap valve I 3 is arranged on the side close to the T-shaped filter 4, so that the on-off of the coke oven gas sent into the T-shaped filter 4 is controlled through the double cooperation of the electric butterfly valve I 2 and the electric flap valve I 3. The electric butterfly valve I 2 and the electric flap valve I 3 are normally open during normal operation, and are closed during stoppage or maintenance.

[0030] As shown in the figure, Figure 1 The check valve II 11, the outlet flow regulating valve 12, the electric flap valve II 13, the electric butterfly valve II 14, the outlet gas plug valve 15 and the pneumatic flow regulating valve 16 are arranged on the gas main pipe in sequence and are communicated at intervals, and the pneumatic flow regulating valve 16 is arranged on the side close to the gas valve station 19, so that the coke oven gas backflow is prevented through the one-way closing of the check valve II 11, the on-off of the coke oven gas sent into the gas valve station 19 is controlled through the double cooperation of the electric butterfly valve II 14 and the electric flap valve II 13, and the flow of the coke oven gas sent into the gas valve station 19 is regulated through the double cooperation of the outlet flow regulating valve 12 and the pneumatic flow regulating valve 16; the number of the gas branch pipes 29 is consistent with the number of the blast furnace tuyeres 20, and the cut-off valve I for controlling the on-off of each gas branch pipe 29 is arranged on each gas branch pipe 29.

[0031] As shown in the figure, Figure 1As shown, the nitrogen bag 17 is communicated with the gas valve station 19 through the nitrogen switch valve 18 and the nitrogen branch pipe 30, and the nitrogen branch pipe 30 is communicated with the corresponding gas branch pipe 29.

[0032] As shown in the figure, Figure 1 The circulating backflow regulating valve 21 is communicated with the gas-liquid separator 10 and the T-shaped filter 4, and the circulating backflow regulating valve 21 is used to return the coke oven gas in the gas-liquid separator 10 to the T-shaped filter 4. As shown in the figure, Figure 1 The emergency loop valve 22 is communicated with the outlet of the check valve I 8 and the inlet of the T-shaped filter 4, and the emergency loop valve 22 is used to return the coke oven gas to the T-shaped filter 4 when the circulating backflow regulating valve 21 cannot be passed in time.

[0033] As shown in the figure, Figure 1 The liquid supplement valve 25 is communicated with the inlet of the compressor 6 and the soft water tank 24, and the liquid supplement valve 25 is used to supplement liquid when the liquid level of the gas-liquid separator 10 is less than or equal to 700 mm.

[0034] As shown in the figure, Figure 1 The liquid injection filter 27 is communicated with the gas-liquid separator 10 and the compressor 6, and the liquid injection filter 27 is used to filter the water separated from the gas-liquid separator 10 and circulate the filtered water to the compressor 6.

[0035] The blast furnace coke oven gas injection system of the present application is used for the blast furnace coke oven gas injection process, and the process comprises the following steps: Figure 1 As shown in the figure, (1) Before normal start, open the liquid supplement valve 25, and continuously supplement the gas-liquid separator 10 with liquid through the liquid supplement valve 25 when the liquid level of the gas-liquid separator 10 is ≤700 mm, and adjust the opening of the circulating backflow regulating valve 21 to 100%; (2) Then open the electric butterfly valve I 2, the electric flap valve I 3, the electric flap valve II 13, the electric butterfly valve II 14, the outlet gas plug valve 15, and the liquid injection regulating valve 26, and close the emergency return valve 22 and the dispersing electric ball valve; (3) Then normally start, at this time the coke oven gas is first sent to the T-shaped filter 4 from the coke oven gas pipe network 1 for dust filtration, the filtered coke oven gas is then sent to the compressor 6 after noise elimination through the silencer I 5 to be pressurized to 0.55-0.7 Mpa, and then the pressurized coke oven gas is sent to the coke oven gas cooler 9 after noise elimination through the silencer II 7 for cooling and temperature reduction to separate the water in the coke oven gas; (4) Then the cooled and temperature-reduced coke oven gas is sent to the gas-liquid separator 10 for further gas-liquid separation treatment, at this time the separated coke oven gas is sent to the gas valve station 19 through the outlet flow regulating valve 12 and the pneumatic flow regulating valve 16 after the double cooperation of the two valves adjusts the size of the gas flow, and then is injected to the corresponding blast furnace tuyere 20 through the gas branch pipe 29, and in the process, the circulating backflow regulating valve 21 is gradually adjusted until the opening of the circulating backflow regulating valve 21 is 0%; At the same time, the separated water is first sent to the compressor 6 after filtration through the liquid injection filter 27 to exchange heat with the coke oven gas in the compressor 6 to reduce the temperature, and then is sent to the coke oven gas cooler 9 to form a circulating loop; (5) When the blast furnace does not accept the injection of coke oven gas due to an emergency accident, the check valve II 11 is closed and the circulating backflow regulating valve 21 is opened, at this time the rich coke oven gas in the gas-liquid separator 10 is backflowed to the T-shaped filter 4 through the circulating backflow regulating valve 21; in the process, if the circulating backflow regulating valve 21 cannot pass in time, the emergency return valve 22 is opened, and the coke oven gas after noise elimination and pressurization is backflowed to the T-shaped filter 4 through the emergency return valve 22; (6) When the pressure of the coke oven gas in the pipeline is ≥20 Kpa, the dispersing electric ball valve 23 is opened, and the coke oven gas is dispersed through the dispersing electric ball valve 23; (7) When it is necessary to stop and overhaul, the electric butterfly valve I 2, the electric flap valve I 3, the electric flap valve II 13, the electric butterfly valve II 14, and the outlet gas plug valve 15 are closed, the circulating backflow regulating valve 21 and the nitrogen switch valve 18 are opened, and the liquid injection regulating valve 26 is closed with a delay of 20 s, at this time the nitrogen is injected into the corresponding blast furnace tuyere 20 through the nitrogen branch pipe 30 to blow the blast furnace.

[0036] The initial opening degree of the liquid injection regulating valve 26 is 100%, and the opening degree value is gradually reduced according to the exhaust temperature requirement, and it is ensured that the opening degree of the liquid injection regulating valve 26 is not less than 50%.

[0037] When the liquid injection pressure is greater than or equal to 0.2 Mpa and the liquid level of the gas-liquid separator 10 is greater than or equal to 900 mm, the liquid supplement valve 25 is automatically closed.

[0038] When the liquid level of the gas-liquid separator 10 is greater than or equal to 1500 mm, the liquid discharge switch valve 28 is opened, and the excess water is discharged through the liquid discharge switch valve 28, so as to realize dynamic balance control.

[0039] The beneficial effects of the present application are as follows: (1) The present application can realize automatic and safe control of coke oven gas injection, and has significant improvement in system integration, process stability, reduction efficiency, safety control and carbon reduction and efficiency increase, and realizes large-scale industrial application. (2) The present application not only can ensure normal and stable operation of coke oven gas injection, but also can quickly implement emergency safety protection measures when an emergency story occurs or maintenance is needed, so as to realize the goal of safe and efficient smelting.

[0040] The above-described embodiments are only preferred embodiments of the present application, and do not limit the concept and scope of the present application. Without departing from the design concept of the present application, various modifications and improvements of the technical solutions of the present application made by ordinary engineering technicians in the art shall fall within the protection scope of the present application. The technical content claimed by the present application has been fully recorded in the technical requirements.

Claims

1. A system for injecting coke oven gas into a blast furnace, characterized by: The application relates to a coke oven gas injection system for blast furnaces, which comprises a T-shaped filter, a muffler I, a compressor, a muffler II, a check valve I, a coke oven gas cooler, a gas-liquid separator, a gas main, a gas valve station and gas branch pipes; the inlet of the T-shaped filter is communicated with a coke oven gas pipe network through a pipeline, and coke oven gas is subjected to dust filtration treatment; the outlet of the T-shaped filter is communicated with the inlet of the gas-liquid separator through a pipeline in sequence via the muffler I, the compressor, the muffler II, the check valve I and the coke oven gas cooler, and filtered coke oven gas is sent into the gas-liquid separator in sequence after being subjected to sound reduction, pressurization and cooling for gas-liquid separation treatment; the gas outlet of the gas-liquid separator is communicated with the gas inlet of the gas valve station through a pipeline via the gas main, and the gas outlet of the gas valve station leads out several gas branch pipes which are respectively communicated with corresponding blast furnace tuyeres, so that coke oven gas after gas-liquid separation is injected into the corresponding blast furnace tuyeres.

2. A system for injection of coke oven gas into a blast furnace according to claim 1, characterized in that: The application further comprises an electric butterfly valve I and an electric flap valve I; the electric butterfly valve I and the electric flap valve I are further arranged on the pipeline between the T-shaped filter and the coke oven gas pipe network in sequence and are spaced apart, and the electric flap valve I is arranged on the side close to the T-shaped filter, so that the electric butterfly valve I and the electric flap valve I are used to control the on-off of coke oven gas sent into the T-shaped filter.

3. A system for injection of coke oven gas into a blast furnace according to claim 2, characterized in that: A check valve II, an outlet flow regulating valve, an electric flap valve II, an electric butterfly valve II, an outlet gas stop valve and a pneumatic flow regulating valve are further arranged on the gas main in sequence and are spaced apart, and the pneumatic flow regulating valve is arranged on the side close to the gas valve station, so that the check valve II is used to prevent coke oven gas from flowing back, the electric butterfly valve II and the electric flap valve II are used to control the on-off of coke oven gas sent into the gas valve station, and the outlet flow regulating valve and the pneumatic flow regulating valve are used to regulate the flow of coke oven gas sent into the gas valve station; the number of the gas branch pipes is consistent with the number of the blast furnace tuyeres, and a cut-off valve I for controlling the on-off of each gas branch pipe is further arranged on each gas branch pipe.

4. A system for injection of coke oven gas into a blast furnace according to claim 3, characterized in that: The application further comprises a nitrogen gas tank, a nitrogen gas on-off valve and nitrogen gas branch pipes; the nitrogen gas tank is communicated with the gas inlet of the gas valve station through the nitrogen gas on-off valve via a pipeline, and each nitrogen gas branch pipe is further arranged on each gas branch pipe between the cut-off valve I and the corresponding blast furnace tuyere; the other end of each nitrogen gas branch pipe away from the corresponding gas branch pipe is communicated with the gas valve station, and a cut-off valve II for controlling the on-off of each nitrogen gas branch pipe is further arranged on each nitrogen gas branch pipe, so that nitrogen gas is injected into the corresponding blast furnace tuyere, and the nitrogen gas on-off valve is used to control the on-off of nitrogen gas sent into the gas valve station.

5. A system for injection of coke oven gas into a blast furnace according to claim 4, characterized in that: It also comprises a circulating backflow regulating valve, an emergency return valve and a dispersing electric ball valve; one end of the circulating backflow regulating valve is communicated with the gas outlet of the gas-liquid separator through a pipeline, and the other end is communicated with the inlet of the T-shaped filter through a pipeline, so that the excess coke oven gas in the gas-liquid separator is backflowed to the T-shaped filter through the circulating backflow regulating valve; one end of the emergency return valve is communicated with the outlet end of the check valve I, and the other end is communicated with the inlet of the T-shaped filter through a pipeline, so that when the circulating backflow regulating valve is not timely, the coke oven gas after being silenced and pressurized is backflowed to the T-shaped filter through the emergency return valve; one end of the dispersing electric ball valve is communicated with the pipeline between the electric flap valve I and the T-shaped filter through a pipeline, and the other end is communicated with the outside through a pipeline, so that when the pressure of the coke oven gas in the pipeline is greater than or equal to 20 KPa, the coke oven gas is dispersed through the dispersing electric ball valve.

6. A system for injection of coke oven gas into a blast furnace according to claim 5, characterized in that: It also comprises a soft water tank and a liquid supplement valve; one end of the liquid supplement valve is communicated with the inlet of the compressor through a pipeline, and the other end is communicated with the soft water tank through a pipeline, so that when the liquid level of the gas-liquid separator is less than or equal to 700 mm, the liquid is supplemented.

7. A system for injection of coke oven gas into a blast furnace according to claim 6, characterized in that: It also comprises a liquid injection regulating valve, a liquid injection filter and a liquid discharge on-off valve; the inlet of the liquid injection filter is communicated with the water outlet of the gas-liquid separator through a pipeline, and the outlet is communicated with the inlet of the compressor through a pipeline via the liquid injection regulating valve, so that the water separated from the gas-liquid separator is circulated to the compressor after being filtered; one end of the liquid discharge on-off valve is communicated with the liquid discharge port of the gas-liquid separator through a pipeline, and the other end is communicated with the outside through a pipeline, so that when the liquid level of the gas-liquid separator is greater than or equal to 1500 mm, the excess water is discharged.

8. A process for injection of a blast furnace with coke oven gas as claimed in claim 7, wherein It comprises the following steps: (1) Before normal start-up, the liquid supplement valve is opened, and the gas-liquid separator is continuously supplemented with liquid through the liquid supplement valve when the liquid level of the gas-liquid separator is less than or equal to 700 mm, and the opening degree of the circulating backflow regulating valve is adjusted to 100%; (2) Then, the electric butterfly valve I, the electric flap valve I, the electric flap valve II, the electric butterfly valve II, the outlet gas plug valve and the liquid injection regulating valve are opened, and the emergency return valve and the dispersing electric ball valve are closed; (3) Then, the normal start-up is performed, at this time, the coke oven gas from the coke oven gas pipeline network is first sent to the T-shaped filter for dust filtration, the filtered coke oven gas is then sent to the compressor after noise elimination by the silencer I to be pressurized to 0.55-0.7 Mpa, and then the pressurized coke oven gas is sent to the coke oven gas cooler after noise elimination by the silencer II for cooling and temperature reduction, so as to separate the water in the coke oven gas; (4) Then, the cooled and temperature-reduced coke oven gas is sent to the gas-liquid separator for further gas-liquid separation treatment, at this time, the separated coke oven gas is adjusted in size by the double cooperation of the outlet flow regulating valve and the pneumatic flow regulating valve, then sent to the gas valve station through the gas main, and then injected to the corresponding blast furnace tuyere through the gas branch pipe, and in this process, the circulating backflow regulating valve is gradually adjusted until the opening degree of the circulating backflow regulating valve is 0%. Meanwhile, the separated water is filtered by the liquid spray filter, and then sent to the compressor to exchange heat with the coke oven gas in the compressor to reduce the temperature of the coke oven gas, and then sent to the coke oven gas cooler to form a reciprocating cycle. (5) When a sudden accident occurs and the blast furnace does not accept the injection of coke oven gas, the check valve II is closed, and the circulation backflow regulating valve is opened. At this time, the excess coke oven gas in the gas-liquid separator is backflowed to the T-shaped filter through the circulation backflow regulating valve. In this process, if the circulation backflow regulating valve cannot pass in time, the emergency return valve is opened, and the coke oven gas after being silenced and pressurized is backflowed to the T-shaped filter through the emergency return valve. (6) When the pressure of the coke oven gas in the pipeline is greater than or equal to 20 KPa, the diffusing electric ball valve is opened, and the coke oven gas is diffused through the diffusing electric ball valve. (7) When it is necessary to shut down for maintenance, the electric butterfly valve I, the electric flap valve I, the electric flap valve II, the electric butterfly valve II, and the outlet gas plug valve are closed, the circulation backflow regulating valve and the nitrogen switch valve are opened, and the liquid injection regulating valve is delayed for 20 s. At this time, nitrogen is injected into the corresponding blast furnace tuyere through the nitrogen branch pipe, thereby purging the blast furnace.

9. A process for injection of a blast furnace with coke oven gas as claimed in claim 8, wherein: The initial opening of the liquid injection regulating valve is 100%, and the opening value is gradually reduced according to the exhaust temperature requirement, and the opening of the liquid injection regulating valve is ensured to be not less than 50%.

10. A process for injection of a blast furnace with coke oven gas as claimed in claim 8 wherein: When the liquid injection pressure is greater than or equal to 0.2 Mpa, and the gas-liquid separator liquid level is greater than or equal to 900 mm, the liquid supplement valve is automatically closed. When the gas-liquid separator liquid level is greater than or equal to 1500 mm, the liquid discharge switch valve is opened, and the excess water is discharged through the liquid discharge switch valve to realize dynamic balance control.

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