Dry quenching process and system capable of adjusting temperature and flow of circulating gas

Abstract

The invention relates to a dry quenching process and system capable of adjusting circulating gas temperature and flow. The system comprises a dry quenching furnace, a primary dust remover, a dry quenching boiler, a secondary dust remover, a water supply preheater and a circulating fan which are connected end to end through inert circulating gas pipelines, the device further comprises a gas mixer, a main pipe flow regulating valve group, a main pipe flowmeter, a branch pipe flow regulating valve group and a branch pipe flowmeter. The invention aims to solve the problem that the wall temperature of a heat exchange tube bundle in the hearth of the dry quenching boiler is overhigh due to the temperature rise of the dry quenching circulating gas, and realizes the adjustable quantity of the circulating gas at the inlet of the dry quenching boiler and the controllable temperature of the circulating gas at the inlet of the dry quenching boiler; meanwhile, the coke powder concentration of circulating gas entering the dry quenching boiler is reduced through the gas mixer, and the safety and stability of operation of a dry quenching system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of utilization of waste heat from dry coke quenching, and in particular to a dry coke quenching process and system capable of adjusting circulating gas temperature and flow rate. Background Art

[0002] The conventional CDQ process is as follows: the coke tank car filled with red coke is pulled by an electric locomotive to the transverse traction device, the transverse traction device pulls the transverse trolley carrying the coke tank from the carrier to the bottom of the lifting derrick, the hoist lifts the coke tank and sends it to the top of the CDQ furnace, and the coke is loaded into the CDQ furnace through the loading device with a distributor; in the CDQ furnace, the coke directly exchanges heat with the inert gas, the coke is cooled to below 200℃, unloaded to the belt conveyor through the coke discharge device, and then sent to the coke Treatment system; the circulating fan blows the inert gas for cooling the coke into the CDQ furnace from the air supply device at the bottom of the CDQ furnace, and exchanges heat with the red-hot coke in countercurrent; the temperature of the hot circulating gas discharged after dust removal by the primary dust collector is about 880-960°C, and it enters the CDQ waste heat boiler for heat exchange, and the temperature drops to 160-180°C; the cold circulating gas coming out of the boiler is dust removed by the secondary dust collector, pressurized by the circulating fan, and then cooled to about 130°C by the feed water preheating device before entering the CDQ furnace for recycling.

[0003] At present, coking enterprises adopt more low-cost coal blending solutions based on the consideration of reducing costs. The circulating gas temperature entering the dry quenching boiler during the dry quenching process is about 1000℃, or even reaches 1050℃, which exceeds the circulating gas inlet temperature of conventional dry quenching boilers, causing the heat exchange tube bundle inside the dry quenching boiler furnace to exceed the wall temperature, and the strength of the heat exchange tube bundle is greatly reduced; at the same time, the circulating gas entering the dry quenching boiler carries a large amount of coke powder. Under the dual effects of coke powder scouring and exceeding the wall temperature, the dry quenching boiler is very prone to tube burst accidents, seriously affecting production safety.

[0004] In order to solve the above problems, some coking enterprises have adopted the method of increasing the flow rate of CDQ inert circulating gas to reduce the inlet circulating gas temperature of CDQ boiler. However, with the increase of inert circulating gas flow rate, another phenomenon that affects safe and stable production has occurred, namely, floating coke in CDQ furnace. Floating coke causes small and medium coke blocks to enter the primary dust collector, resulting in ash discharge failure of the primary dust collector, and also brings a large amount of coke powder into the CDQ boiler, resulting in increased wear of the heat exchange tube bundle inside the CDQ boiler. Summary of the invention

[0005] The present invention provides a dry coke quenching process and system capable of adjusting the temperature and flow of circulating gas, with the purpose of solving the problem of excessive wall temperature of heat exchange tube bundles in the furnace of a dry coke quenching boiler caused by the increase of the temperature of the dry coke quenching circulating gas, thereby achieving adjustable circulating gas volume at the inlet of the dry coke quenching furnace and controllable circulating gas temperature at the inlet of the dry coke quenching boiler; at the same time, the coke powder concentration of the circulating gas entering the dry coke quenching boiler is reduced by a mixer, thereby improving the safety and stability of the operation of the dry coke quenching system.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A coke dry quenching process capable of adjusting the temperature and flow rate of circulating gas comprises the following steps:

[0008] 1) After the red-hot coke enters the CDQ furnace, it is cooled by the inert circulating gas. The cooled coke is measured by the coke discharge metering scale and then discharged quantitatively;

[0009] 2) The high-temperature inert circulating gas of 880-1000°C generated after heat exchange with red-hot coke in the CDQ furnace enters the primary dust collector to remove large coke particles, and then enters the mixer to mix with the low-temperature inert circulating gas before returning to the CDQ furnace to adjust the temperature of the inert circulating gas entering the CDQ boiler;

[0010] 3) The inert circulating gas adjusted to below 850°C by the aerator enters the CDQ boiler to recover heat, and then passes through the secondary dust collector to remove small particles of coke powder;

[0011] 4) The inert circulating gas after secondary dust removal is pressurized by the circulating fan and enters the feed water preheater. After recovering the waste heat, the temperature drops to below 130°C. The low-temperature inert circulating gas below 130°C is divided into two paths; one path enters the inert circulating gas main pipe, and returns to the CDQ furnace after the flow is adjusted by the main pipe flow regulating valve group and the main pipe flow meter; the other path enters the inert circulating gas branch pipe, and enters the mixer after the flow is adjusted by the branch pipe flow regulating valve group and the branch pipe flow meter to mix with the high-temperature inert circulating gas.

[0012] A dry coke quenching system capable of adjusting the temperature and flow of circulating gas comprises a dry coke quenching furnace, a primary dust collector, a dry coke quenching boiler, a secondary dust collector, a feed water preheater and a circulating fan connected end to end through an inert circulating gas pipeline; further comprises an aerator, a main pipe flow regulating valve group, a main pipe flow meter, a branch pipe flow regulating valve group and a branch pipe flow meter; the aerator is arranged on the inert circulating gas pipeline between the primary dust collector and the dry coke quenching boiler; the inert circulating gas pipeline downstream of the feed water preheater is divided into an inert circulating gas main pipe and an inert circulating gas branch pipe, the inert circulating gas main pipe is connected to the feed water preheater and the aerator, and the inert circulating gas branch pipe is connected to the feed water preheater and the dry coke quenching furnace; along the flow direction of the inert circulating gas, the inert circulating gas main pipe is sequentially provided with a main pipe flow regulating valve group and a main pipe flow meter, and the inert circulating gas branch pipe is sequentially provided with a branch pipe flow regulating valve group and a branch pipe flow meter; the coke discharge device of the dry coke quenching furnace is provided with a coke discharge metering scale.

[0013] The main pipe flow regulating valve group, the main pipe flow meter and the coke discharge metering scale are interlocked and controlled by a control system; the branch pipe flow regulating valve group and the branch pipe flow meter are interlocked and controlled by a control system.

[0014] An inlet thermometer is arranged at the inlet of the CDQ boiler and an outlet thermometer is arranged at the outlet of the CDQ furnace. The inlet thermometer and the outlet thermometer are interlocked and controlled with the main flow regulating valve group and the main flow meter through the control system.

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

[0016] 1) According to the coke discharge amount signal transmitted by the coke discharge metering scale, the opening of the main flow regulating valve group on the inert circulating gas main pipe is controlled to keep the inert circulating gas flow rate into the furnace consistent with the coke discharge amount, so that the circulating gas temperature at the CDQ furnace outlet is kept below 1000°C; compared with the method of artificially increasing the inert circulating gas flow rate to prevent the CDQ boiler inlet circulating gas temperature from overheating in the prior art, the generation of floating coke in the CDQ furnace can be avoided;

[0017] 2) The high-temperature inert circulating gas and the low-temperature inert circulating gas are mixed through the mixer to keep the circulating gas temperature at the CDQ boiler inlet below 850°C, thus solving the problem of the CDQ boiler internal heat exchange tube bundle exceeding the wall temperature due to the increase in the circulating gas temperature at the CDQ boiler inlet, which in turn causes the boiler tube burst accident;

[0018] 3) The added aerator can reduce the coke powder concentration in the inert circulating gas entering the dry coke quenching boiler, which is beneficial to reduce the wear of the heat exchange tube bundle inside the dry coke quenching boiler and increase the service life of the dry coke quenching boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a structural schematic diagram of a dry coke quenching system capable of adjusting the temperature and flow of circulating gas according to the present invention.

[0020] In the figure: 1. CDQ furnace 2. Coke discharge metering scale 3. Primary dust collector 4. Aerator 5. CDQ boiler 6. Inlet thermometer 7. Secondary dust collector 8. Inert circulating gas pipeline 9. Circulating fan 10. Feed water preheater 11. Inert circulating gas main pipe 12. Main pipe flow control valve group 13. Main pipe flow meter 14. Inert circulating gas branch pipe 15. Branch pipe flow control valve group 16. Branch pipe flow meter 17. Outlet thermometer DETAILED DESCRIPTION

[0021] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0022] like Figure 1 As shown, the dry coke quenching process capable of adjusting the temperature and flow rate of circulating gas according to the present invention comprises the following steps:

[0023] 1) After the red-hot coke enters the dry quenching furnace 1, it is cooled by the inert circulating gas, and the cooled coke is measured by the coke discharge metering scale 2 and then discharged quantitatively;

[0024] 2) The high-temperature inert circulating gas of 880-1000°C generated after heat exchange with red-hot coke in the CDQ furnace 1 enters the primary dust collector 3 to remove large coke powder, and then enters the mixer 4 to mix with the low-temperature inert circulating gas before returning to the CDQ furnace 1 to adjust the temperature of the inert circulating gas entering the CDQ boiler 5;

[0025] 3) The inert circulating gas adjusted to below 850°C by the aerator 4 enters the dry quenching boiler 5 to recover heat, and then passes through the secondary dust collector 7 to remove small particles of coke powder;

[0026] 4) The inert circulating gas after secondary dust removal is pressurized by the circulating fan 9 and enters the feed water preheater 10. After the waste heat is recovered, the temperature drops to below 130°C. The low-temperature inert circulating gas below 130°C is divided into two paths; one path enters the inert circulating gas main pipe 11, and returns to the CDQ furnace 1 after the flow is adjusted by the main pipe flow regulating valve group 12 and the main pipe flow meter 13; the other path enters the inert circulating gas branch pipe 14, and enters the mixer 4 after the flow is adjusted by the branch pipe flow regulating valve group 15 and the branch pipe flow meter 16 to mix with the high-temperature inert circulating gas.

[0027] The present invention discloses a coke dry quenching system capable of adjusting the temperature and flow of circulating gas, comprising a coke dry quenching furnace 1, a primary dust collector 3, a coke dry quenching boiler 5, a secondary dust collector 7, a feed water preheater 10 and a circulating fan 9 connected end to end through an inert circulating gas pipeline 8; further comprising an aerator 4, a main pipe flow regulating valve group 12, a main pipe flow meter 13, a branch pipe flow regulating valve group 15 and a branch pipe flow meter 16; the aerator 4 is arranged on the inert circulating gas pipeline 8 between the primary dust collector 3 and the coke dry quenching boiler 5; the inert gas downstream of the feed water preheater 10 The circulating gas pipeline 8 is divided into an inert circulating gas main pipe 11 and an inert circulating gas branch pipe 14. The inert circulating gas main pipe 11 connects the feed water preheater 10 and the mixer 4, and the inert circulating gas branch pipe 14 connects the feed water preheater 10 and the CDQ furnace 1. Along the flow direction of the inert circulating gas, a main pipe flow regulating valve group 12 and a main pipe flow meter 13 are sequentially arranged on the inert circulating gas main pipe 11, and a branch pipe flow regulating valve group 15 and a branch pipe flow meter 16 are sequentially arranged on the inert circulating gas branch pipe 14. The coke discharge device of the CDQ furnace 1 is provided with a coke discharge metering scale 2.

[0028] The main pipe flow regulating valve group 12, the main pipe flow meter 13 and the coke discharge metering scale 2 are interlocked and controlled by a control system; the branch pipe flow regulating valve group 14 and the branch pipe flow meter 15 are interlocked and controlled by a control system.

[0029] An inlet thermometer 6 is provided at the inlet of the CDQ boiler 5 ; an outlet thermometer 17 is provided at the outlet of the CDQ furnace 1 ; the inlet thermometer 6 and the outlet thermometer 17 are interlocked and controlled with the main flow regulating valve group 12 and the main flow meter 13 through the control system.

[0030] The present invention discloses a coke dry quenching system capable of adjusting the temperature and flow of circulating gas, comprising a coke dry quenching furnace 1, a coke discharge metering scale 2, a primary dust collector 3, an aerator 4, a coke dry quenching boiler 5, an inlet thermometer 6, a secondary dust collector 7, an inert circulating gas pipeline 8, a circulating fan 9, a feed water preheater 10, an inert circulating gas main pipe 11, a main pipe flow regulating valve group 12, a main pipe flow meter 13, an inert circulating gas branch pipe 14, a branch pipe flow regulating valve group 15, a branch pipe flow meter 16 and an outlet thermometer 17.

[0031] The coke discharge metering scale 2 is arranged at the coke discharge port of the coke discharge device of the CDQ furnace 1. According to the coke discharge amount signal transmitted by the coke discharge metering scale 2, the opening of the main flow regulating valve group 12 is controlled, the amount of inert circulating gas is adjusted to be consistent with the coke discharge amount, and the temperature value of the outlet thermometer 17 is controlled to be maintained within 1000°C.

[0032] The low-temperature inert circulating gas below 130° C. after the feed water preheater 10 is divided into two paths, one path enters the CDQ furnace 1 through the inert circulating gas main pipe 11 , and the other path enters the mixer 4 through the inert circulating gas branch pipe 14 .

[0033] The inert circulating gas main pipe 11 is located between the feed water preheater 10 and the CDQ furnace 1 , and is provided with a main pipe flow regulating valve group 12 and a main pipe flow meter 13 .

[0034] The inert circulating gas branch pipe 14 is located between the feed water preheater 10 and the aerator 4 , and is provided with a branch pipe flow regulating valve group 15 and a branch pipe flow meter 16 .

[0035] The aerator 4 is arranged on the inert circulating gas pipeline 8 between the primary dust collector 3 and the dry coke quenching boiler 5. The high-temperature inert circulating gas with a large amount of coke powder particles and a temperature of about 1000°C and the low-temperature inert circulating gas with a temperature below 130°C after being purified by the secondary dust collector 7 are mixed in the aerator 4, thereby reducing the coke powder concentration of the inert circulating gas entering the dry coke quenching boiler 5.

[0036] An inlet thermometer 6 is provided at the inlet of the dry coke quenching boiler 5. According to the signal of the inlet thermometer 6, the opening of the branch pipe flow regulating valve group 15 is adjusted to control the flow of the low-temperature inert circulating gas entering the inert circulating gas branch pipe 14, so that the high-temperature inert circulating gas with a temperature adjusted to below 850° C. enters the dry coke quenching boiler 5.

[0037] The present invention discloses a coke dry quenching process and system capable of adjusting the temperature and flow rate of circulating gas, which automatically adjusts the amount of inert circulating gas according to the amount of coke discharge, so that the amount of inert circulating gas is consistent with the amount of coke discharge, thereby avoiding the occurrence of floating coke. The low-temperature inert circulating gas with a temperature lower than 130°C after being purified by the secondary dust collector 7 is divided into two paths, wherein most of the low-temperature inert circulating gas enters the CDQ furnace 1 after the flow rate is adjusted by the main flow regulating valve group 12 and the main flow meter 13, and is heated to about 1000°C after cooling the coke, and the high-temperature inert circulating gas after heat exchange and heating enters the primary dust collector 3; a small part of the low-temperature inert circulating gas enters the mixer 4 after the flow rate is adjusted by the branch pipe flow regulating valve group 15 and the branch pipe flow meter 16, and is mixed with the high-temperature inert circulating gas after the primary dust collector 3, and the temperature is adjusted to less than 850°C, and then enters the CDQ boiler 5, thereby reducing the wall temperature of the heat exchange tube bundle inside the CDQ boiler 5, and realizing that the amount of circulating gas at the inlet of the CDQ furnace 1 is adjustable and the temperature of circulating gas at the inlet of the CDQ boiler 5 is controllable; at the same time, through gas mixing, the high-temperature inert circulating gas with more coke powder particles is mixed with the purified low-temperature inert circulating gas, thereby reducing the coke powder concentration of the inert circulating gas entering the CDQ boiler 5.

[0038] The present invention is applicable to a waste heat recovery system for dry coke quenching, and is also applicable to other waste heat recovery systems with similar process routes.

[0039] 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 coke dry quenching process capable of adjusting the temperature and flow rate of circulating gas, characterized in that: The process includes the following: 1) After the red-hot coke enters the CDQ furnace, it is cooled by the inert circulating gas. The cooled coke is measured by the coke discharge metering scale and then discharged quantitatively; 2) The high-temperature inert circulating gas of 880-1000°C generated after heat exchange with red-hot coke in the CDQ furnace enters the primary dust collector to remove large coke particles, and then enters the mixer to mix with the low-temperature inert circulating gas before returning to the CDQ furnace to adjust the temperature of the inert circulating gas entering the CDQ boiler; 3) The inert circulating gas adjusted to below 850°C by the aerator enters the CDQ boiler to recover heat, and then passes through the secondary dust collector to remove small particles of coke powder; 4) The inert circulating gas after secondary dust removal is pressurized by the circulating fan and enters the feed water preheater. After recovering the waste heat, the temperature drops to below 130°C. The low-temperature inert circulating gas below 130°C is divided into two paths; one path enters the inert circulating gas main pipe, and returns to the CDQ furnace after the flow is adjusted by the main pipe flow regulating valve group and the main pipe flow meter; the other path enters the inert circulating gas branch pipe, and enters the mixer after the flow is adjusted by the branch pipe flow regulating valve group and the branch pipe flow meter to mix with the high-temperature inert circulating gas.

2. A coke dry quenching system with adjustable circulating gas temperature and flow rate for realizing the process as claimed in claim 1, comprising a coke dry quenching furnace, a primary dust collector, a coke dry quenching boiler, a secondary dust collector, a feed water preheater and a circulating fan connected end to end through an inert circulating gas pipeline; characterized in that: It also includes a mixer, a main pipe flow regulating valve group, a main pipe flow meter, a branch pipe flow regulating valve group and a branch pipe flow meter; the mixer is arranged on the inert circulating gas pipeline between the primary dust collector and the dry coke quenching boiler; the inert circulating gas pipeline downstream of the feed water preheater is divided into an inert circulating gas main pipe and an inert circulating gas branch pipe, the inert circulating gas main pipe connects the feed water preheater and the mixer, and the inert circulating gas branch pipe connects the feed water preheater and the dry coke quenching furnace; along the flow direction of the inert circulating gas, the inert circulating gas main pipe is sequentially provided with a main pipe flow regulating valve group and a main pipe flow meter, and the inert circulating gas branch pipe is sequentially provided with a branch pipe flow regulating valve group and a branch pipe flow meter; the coke discharge device of the dry coke quenching furnace is provided with a coke discharge metering scale.

3. A coke dry quenching system capable of adjusting circulating gas temperature and flow rate according to claim 2, characterized in that: The main pipe flow regulating valve group, the main pipe flow meter and the coke discharge metering scale are interlocked and controlled by a control system; the branch pipe flow regulating valve group and the branch pipe flow meter are interlocked and controlled by a control system.

4. A coke dry quenching system capable of adjusting circulating gas temperature and flow rate according to claim 2, characterized in that: An inlet thermometer is arranged at the inlet of the CDQ boiler and an outlet thermometer is arranged at the outlet of the CDQ furnace. The inlet thermometer and the outlet thermometer are interlocked and controlled with the main flow regulating valve group and the main flow meter through the control system.

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