Multi-medium co-combustion air-discharged gas oxidation device and method adopting coal water slurry synthesis gas for energy supplementation

Abstract

The invention discloses a multi-medium co-combustion air-discharged gas oxidation device and method adopting coal water slurry synthesis gas for energy supplementation, the multi-medium co-combustion air-discharged gas oxidation device comprises a coal water slurry gasification device and a heat storage oxidation device, and a heat regenerator is connected between the coal water slurry gasification device and the heat storage oxidation device; the secondary fan is connected with the coal water slurry gasification device through the low-temperature energy saver and the heat regenerator; the primary fan is connected to an ignition air duct of the coal water slurry gasification device through the low-temperature energy saver; the coal water slurry gasification device is connected with the mixer; the low-temperature energy saver is connected with the secondary fan and the primary fan; the heat storage oxidation device is connected with the waste heat boiler; the amount of synthesis gas entering the mixer is accurately controlled by a control system; and the windblown gas is respectively used as feed gas of the system and a gasifying agent of the coal water slurry gasifying device. The problem that the windblown gas of most mines lacking gas extraction for adjusting the concentration of the windblown gas cannot be continuously oxidized due to low methane concentration is solved, the windblown gas can be successfully destroyed at low cost, and the purpose of coal mine methane emission reduction is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of methane emission reduction, and specifically relates to a multi-medium mixed combustion air-drained gas oxidation device using water coal slurry synthesis gas for energy supplement; it also relates to a multi-medium mixed combustion air-drained gas oxidation method using water coal slurry synthesis gas for energy supplement. Background Art

[0002] Mine air-drained gas, also known as ventilation gas, refers to the fresh air sent from the ground to the underground, which dilutes the underground gas concentration and is then discharged from the return air shaft. The volume fraction of methane in the air-drained gas stipulated in the "Coal Mine Safety Regulations" is less than 0.75%.

[0003] The methane concentration in the air-drained gas is extremely low, but the total amount converted to pure methane is huge. The combustible component (methane) in the air-drained gas is a strong greenhouse gas, and its greenhouse effect is 25 times that of carbon dioxide. Among the utilization methods of gas, for gas with a methane concentration less than 8%, the regenerative oxidation method is generally used for destruction. Methane undergoes an oxidation reaction in the combustion chamber of the regenerative oxidation device to form high-temperature flue gas, which supplies heat to the coal mine thermal users.

[0004] The regenerative oxidation device has a self-thermal equilibrium concentration, and the prerequisite for its normal operation is that the concentration of the gas mixture in the device is higher than its self-thermal equilibrium concentration. The methane concentration in the air-drained gas is generally less than 0.2%, which is lower than the self-thermal equilibrium concentration of the regenerative oxidation device. Therefore, the air-drained gas cannot independently operate the regenerative oxidation device.

[0005] Currently, a few coal mines adopt the method of mixing air-drained gas with extracted gas to increase the air-drained gas concentration to more than 1%, and then enter the regenerative oxidation device for destruction. However, extracted gas only exists in high-gas mines and outburst gas mines in China, and low-gas mines generally do not build extraction pump stations. According to statistics, among the total amount of the above-mentioned air-drained gas, the air-drained gas with the source of extracted gas for mixing accounts for only about 5%. Theoretically, this part of the air-drained gas can be utilized by the current technology, but the vast majority (accounting for 95%) of the air-drained gas has no conditions to mix with extracted gas and can only be discharged, causing environmental pollution. Summary of the Invention

[0006] The purpose of the present invention is to provide a multi-medium mixed combustion air-drained gas oxidation device using water coal slurry synthesis gas for energy supplement, which solves the problem that the air-drained gas in most mines lacking the adjustment of air-drained gas concentration by extracted gas cannot be continuously and uninterruptedly oxidized due to the low methane concentration; it can successfully achieve the destruction of air-drained gas at low cost and achieve the purpose of methane emission reduction in coal mines.

[0007] The purpose of the present invention is to provide a multi-medium mixed combustion air-drained gas oxidation method using water coal slurry synthesis gas for energy supplement.

[0008] The technical solution adopted by the present invention is: a multi-medium mixed combustion air-discharged gas oxidation device supplemented with energy by water slurry synthesis gas, including a water slurry gasification device and a regenerative oxidation device, with a regenerator connected between the water slurry gasification device and the regenerative oxidation device; a secondary air blower is connected to the water slurry gasification device through a low-temperature energy-saving device and a regenerator; a primary air blower is connected to the ignition air duct of the water slurry gasification device through a low-temperature energy-saving device; the water slurry gasification device is connected to a mixer; it also includes a control system, which is used to control each valve body on the connecting pipeline to achieve flow regulation.

[0009] The characteristics of the present invention also lie in that A water slurry storage funnel is connected to the water slurry gasification device. The regenerative oxidation device includes a combustion chamber and regenerators, with no less than 2 groups of regenerators arranged at intervals; a synthesis gas burner is arranged in the combustion chamber.

[0010] A dust collector is also connected between the regenerator and the water slurry gasification device. The dust collector is connected to a return feeder, and the return feeder is connected to a Roots blower; a flame arrester is also arranged on the connecting pipeline between the regenerator and the synthesis gas burner; the water slurry synthesis gas coming out of the flame arrester is divided into two paths. One path is connected to the inlet of the synthesis gas burner through a regulating valve V7, and the other path is connected to the mixer through a regulating valve V8. A gas flow meter for detecting the synthesis gas flow is arranged at the inlet end of the mixer; the return feeder is connected to the Roots blower.

[0011] The outlet of the mixer is connected to the regenerator of the regenerative oxidation device through a cut-off valve group. The high-temperature flue gas outlet at the top of the regenerative oxidation device is connected to the heat source inlet of the waste heat boiler through a regulating valve V4. The heat source outlet of the waste heat boiler is connected to the hot fluid inlet of the low-temperature energy-saving device, and the hot fluid outlet of the low-temperature energy-saving device is connected to the chimney.

[0012] The outlets of the secondary air blower and the primary air blower are respectively connected to the two cold fluid inlets of the low-temperature energy-saving device through regulating valves V5 and V6; one of the cold fluids from the secondary air blower in the low-temperature energy-saving device is connected to the cold fluid inlet of the regenerator, and the other cold fluid from the primary air blower is connected to the ignition air duct of the water slurry gasification device. The cold fluid outlet of the regenerator is connected to the furnace chamber of the water slurry gasification device. The hot fluid inlet of the regenerator is connected to the gas outlet of the dust collector, and the hot fluid outlet of the regenerator is connected to the inlet of the flame arrester; The ignition air duct communicates with the feed inlet of the water slurry gasification device; the water slurry storage funnel is connected to the feed inlet of the water slurry gasification device through a regulating valve V9 and a water slurry metering device in sequence; Three temperature sensors are evenly arranged inside the combustion chamber to monitor the temperature of the combustion chamber; a gas full-component analyzer is arranged at the outlet of the mixer to monitor the composition of the raw material gas entering the regenerative oxidation device; a water slurry metering device is arranged on the water slurry feed pipeline to control the combustion intensity of the water slurry gasification device.

[0013] The second technical solution adopted by the present invention is: a multi-medium mixed combustion and wind-discharged gas oxidation method using water coal slurry synthesis gas for energy supplementation: specifically as follows: The wind-discharged gas is divided into four paths: The first path of wind-discharged gas and the cooled water coal slurry synthesis gas are mixed and then enter the regenerative oxidation device. Part of the heat is recovered by the regenerator, and the other part of the heat enters the waste heat boiler to produce steam, providing heat for heat users; The first path of wind-discharged gas and the cooled water coal slurry synthesis gas are mixed in a mixer to adjust the calorific value of the wind-discharged gas; after the calorific value of the wind-discharged gas is adjusted, it enters the regenerator of one of the oxidation beds of the regenerative oxidation device through a cut-off valve group, is preheated to 550°C ± 25°C, continues to absorb heat in the combustion chamber and then undergoes an oxidation reaction, generating a large amount of heat; part of the high-temperature flue gas generated in the combustion chamber enters the chimney for exhausting after recovering heat through the regenerator of the other oxidation bed of the regenerative oxidation device, and the other part of the high-temperature flue gas is extracted from the regulating valve V4 at the top of the regenerative oxidation device and then enters the waste heat boiler to produce steam, providing heat for heat users. The flue gas coming out of the waste heat boiler preheats the wind-discharged gas through a low-temperature energy saver and then enters the chimney; The second path of wind-discharged gas is pressurized by a primary fan, heated by a low-temperature energy saver, and then enters the water coal slurry gasification device and the ignition air duct as the combustion-supporting gas for the water coal slurry gasification device; The third path of wind-discharged gas is pressurized by a secondary fan, heated by a low-temperature energy saver, enters the recuperator to recover the heat of the synthesis gas, and then evenly enters the furnace of the water coal slurry gasification device as the combustion-supporting gas for the water coal slurry gasification device; The fourth path of wind-discharged gas sequentially passes through the regulating valve V3 and the Roots blower and enters the feeder, mixes with the solid particles coming down from the dust collector, and then enters the furnace of the water coal slurry gasification device.

[0014] The method of control using a control system is specifically as follows: The readings of the gas full-component analyzer at the outlet of the mixer are fed back to the control system. After receiving the reading signals of the gas full-component analyzer, the control system controls the opening degrees of the regulating valves V1, V2, and V8; specifically: (1) When the volume fraction of hydrogen in the readings of the gas full-component analyzer is greater than 0.5% or the volume fraction of carbon monoxide is greater than 1%, the opening degree of V8 is reduced to lower the volume fractions of hydrogen and carbon monoxide; (2) When the volume fraction of hydrogen in the readings of the gas full-component analyzer is greater than 1% or the volume fraction of carbon monoxide is greater than 2%, the regulating valve V2 is closed, and it is strictly prohibited for the mixed gas to enter the regenerative oxidation device through the regulating valve V2; (3) When the volume fraction of methane in the readings of the gas full-component analyzer is greater than 1.5%, the regulating valves V2, V1, V3, V5, and V6 are closed, and it is strictly prohibited for the mixed gas to enter the regenerative oxidation device through the regulating valve V2.

[0015] The readings of the flow meters on the two inlet pipes of the mixer are fed back to the control system. After receiving the reading signal from the gas full-component analyzer, the control system controls the opening of the control valve V8 to control the flow rate of the syngas entering the mixer, thereby controlling the equivalent methane concentration of the mixed gas at the outlet of the mixer. ; The flow rate Q of the syngas sg is calculated according to the following formula:

[0016] In the formula: —— The flow rate of the syngas, Nm 3 / h; —— The flow rate of the wind-discharged gas, monitored by the gas flow meter after the control valve V1, Nm 3 / h; —— The equivalent methane volume concentration after mixing, 0.4% - 1.0%, not exceeding 1.5% at most, preset in the control system according to the stable operation of the regenerative oxidation device, and the set value is displayed online; —— The methane concentration of the wind-discharged gas, detected in real time by the online gas sensor at the return air shaft, and this value is uploaded to the control system; —— The low calorific value of the syngas, detected in real time from the physical properties of the syngas, and this monitored value is uploaded to the control system, MJ / Nm 3 .

[0017] The control system controls the flow rate of the wind-discharged gas entering the Roots blower through the control valve V3 to maintain the height of the solid particles in the return feeder within a certain range; The control system controls the flow rate of the wind-discharged gas entering the coal water slurry gasification device as the combustion-supporting gas through the control valves V6 and V5. The control system controls the flow rate of the coal water slurry entering the coal water slurry gasification device through the control valve V9. By adopting the above control, the combustion intensity of the coal water slurry is maintained, and the flow rate of the syngas entering the mixer through the control valve V8 and the flow rate of the syngas entering the syngas burner through the control valve V7 are ensured, and finally the average temperature of the combustion chamber is ensured; The control system controls the amount of high-temperature flue gas extracted from the top of the combustion chamber through the control valve V4 to maintain the average temperature of the combustion chamber at 750°C - 950°C; After the average temperature of the combustion chamber increases to 950 °C, close regulating valves V3, V5, V6, and V7, and keep regulating valve V4 open to reduce the average temperature of the combustion chamber; when the average temperature of the combustion chamber drops below 750 °C, open regulating valves V3, V5, V6, and V7 simultaneously, and close regulating valve V4 to increase the average temperature of the combustion chamber; after regulating valve V4 is closed, when the average temperature of the combustion chamber increases to 820 °C, open regulating valve V4; thus, by adjusting the opening degrees of the above valves, the average temperature of the combustion chamber is maintained between 750 °C and 950 °C.

[0018] The beneficial effects of the present invention are as follows: The water slurry gasification device of the present invention can utilize syngas to mix and discharge gas with air, improve the calorific value of the gas discharged with air entering the regenerator of the regenerative oxidation device, increase the heat output after oxidation, so that the temperature of the oxidation device is maintained within the self-thermal balance range, enabling its continuous reaction and reducing methane emissions.

[0019] Compared with mixing and burning solid fuels (such as pulverized coal, biomass powder, etc.), the device of the present invention can prevent solid particles (coal combustion, fly ash, slag, etc.) from entering the regenerator (generally honeycomb ceramics of porous media) and the combustion chamber, thus avoiding the blockage of the regenerator due to the settlement or coking of solid particles on the surface of the porous micro-channels of the regenerator. In addition, water slurry is a deeply clean coal-based liquid fuel with stable combustion, less pollution emissions, much easier feeding and accurate metering to an external combustion furnace. The combustibles in it have a high combustion efficiency, a large heat supplement per unit fuel, save fuel consumption, and produce extremely low harmful gases to the atmosphere during combustion.

[0020] The water slurry gasification device of the present invention uses air to discharge gas instead of air, which can make full use of the energy of methane in the air-discharged gas as much as possible, improve the thermal efficiency of the entire gas system, and utilize more air-discharged gas, that is, achieve zero emission of air-discharged gas.

[0021] Compared with directly mixing and supplementing heat with the high-temperature flue gas of a coal-fired furnace to the combustion chamber, it can prevent the dilution of the gas discharged with air entering the regenerative oxidation device by the heat-supplementing gas, thus avoiding further reduction of the methane concentration in the extremely low-concentration gas discharged with air raw material gas and saving heat-supplementing fuel.

[0022] The above method can also avoid the interruption of heat supply to heat users, reduce the risk of heat insulation interruption, and reduce the operating cost and safety risk of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of a multi-media mixed combustion air-discharged gas oxidation device using water slurry syngas for energy supplement of the present invention.

[0024] In the figure, 1. mixer, 2. secondary air blower, 3. primary air blower, 4. syngas burner, 5. flame arrester, 6. low-temperature energy saver, 7. waste heat boiler, 8. Roots blower, 9. dust collector, 10. water coal slurry gasification unit, 11. ignition air duct, 12. water coal slurry storage hopper, 13. regenerative thermal oxidation unit, 14. loop seal, 15. water coal slurry metering device, 16. regenerator, 17. control system. Detailed implementation mode

[0025] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0026] Embodiment 1 The multi-medium mixed combustion and wind-discharged gas oxidation device using water coal slurry syngas for energy supplementation of the present invention includes a water coal slurry gasification unit 10 and a regenerative thermal oxidation unit 13. A regenerator 16 is connected between the water coal slurry gasification unit 10 and the regenerative thermal oxidation unit 13; the secondary air blower 2 is connected to the water coal slurry gasification unit 10 through a low-temperature energy saver 6 and a regenerator 16; the primary air blower 3 is connected to the ignition air duct 11 of the water coal slurry gasification unit 10 through a low-temperature energy saver 6; the water coal slurry gasification unit 10 is connected to the mixer 1; a control system 17 is further included, and the control system 17 is used to control each valve body on the connecting pipeline to achieve flow regulation.

[0027] Embodiment 2 On the basis of Embodiment 1, a water coal slurry storage hopper 12 is connected to the water coal slurry gasification unit 10. The regenerative thermal oxidation unit 13 includes a combustion chamber and regenerators. The number of regenerators is not less than 2 groups and they are arranged at intervals; a syngas burner 4 is arranged in the combustion chamber.

[0028] A dust collector 9 is further connected between the regenerator 16 and the water coal slurry gasification unit 10. The dust collector 9 is connected to a loop seal 14, and the loop seal 14 is connected to a Roots blower 8; a flame arrester 5 is also arranged on the connecting pipeline between the regenerator 16 and the syngas burner 4; the water coal slurry syngas coming out of the flame arrester 5 is divided into two paths. One path is connected to the inlet of the syngas burner 4 through a regulating valve V7, and the other path is connected to the mixer 1 through a regulating valve V8. A gas flow meter for detecting the syngas flow is arranged at the inlet end of the mixer 1.

[0029] The outlet of the mixer 1 is connected to the regenerator of the regenerative thermal oxidation unit 13 through a cut-off valve group. The high-temperature flue gas outlet at the top of the regenerative thermal oxidation unit 13 is connected to the heat source inlet of the waste heat boiler 7 through a regulating valve V4. The heat source outlet of the waste heat boiler 7 is connected to the hot fluid inlet of the low-temperature energy saver 6, and the hot fluid outlet of the low-temperature energy saver 6 is connected to the chimney.

[0030] The outlets of the secondary fan 2 and the primary fan 3 are connected to the two cold fluid inlets of the low-temperature economizer 6 through regulating valves V5 and V6 respectively; one of the cold fluids from the secondary fan of the low-temperature economizer 6 is connected to the cold fluid inlet of the regenerator 16, and the other cold fluid from the primary fan is connected to the ignition air duct 11 of the water-coal slurry gasification device 10.

[0031] In this embodiment, the secondary fan 2 and the primary fan 3 provide power for the exhaust gas to overcome the resistance of the low-temperature economizer 6, the regenerator 16, the dust collector 9, the valve and the pipeline. The low-temperature economizer 6 is used to recover the waste heat of the flue gas from the heat user, reduce the thermal enthalpy of the flue gas entering the chimney as much as possible, and improve the overall thermal efficiency. The regenerator 16 is used to recover the waste heat of the synthesis gas, further preheat the exhaust gas entering the furnace, and finally improve the overall thermal efficiency.

[0032] Adding exhaust gas to the water-coal slurry gasifier instead of air can make full use of the energy of methane in the exhaust gas, thereby improving the thermal efficiency of the entire gas system and utilizing more exhaust gas, that is, achieving zero emission of exhaust gas.

[0033] The cold fluid outlet of the regenerator 16 is connected to the furnace of the water-coal slurry gasification device 10, the hot fluid inlet of the regenerator 16 is connected to the gas outlet of the dust collector 9, and the hot fluid outlet of the regenerator 16 is connected to the inlet of the flame arrester 5; The ignition air duct 11 is connected to the feed port of the water-coal slurry gasification device 10 ; the water-coal slurry storage funnel 12 is connected to the feed port of the water-coal slurry gasification device 10 after passing through the regulating valve V9 and the water-coal slurry metering device 15 in sequence.

[0034] Three temperature sensors are evenly arranged inside the combustion chamber to monitor the temperature of the combustion chamber; a gas full-component analyzer is set at the outlet of mixer 1 to monitor the composition of the raw gas entering the thermal storage oxidation device.

[0035] Example 3 like Figure 1 As shown, the multi-media mixed combustion air exhaust gas oxidation device for water-coal slurry synthesis gas supplementation disclosed in this embodiment includes: a mixer 1, a secondary fan 2, a primary fan 3, a synthesis gas burner 4, a flame arrester 5, a low-temperature energy saver 6, a waste heat boiler 7, a Roots blower 8, a dust collector 9, a water-coal slurry gasification device 10, an ignition air duct 11, a water-coal slurry storage funnel 12, a thermal storage oxidation device 13, a return device 14, a water-coal slurry metering device 15, a heat regenerator 16, and a control system 17. The thermal storage oxidation device 13 includes a heat storage body and a combustion chamber. The device also includes corresponding regulating valves, shut-off valves, temperature sensors, gas full component analyzers, and gas flow meters. Among them, the wind-discharged gas is divided into 4 paths through pipelines and regulating valves. The first path is connected to the wind-discharged gas inlet of the mixer 1, the second path is connected to the inlet of the roots blower 8, the third path is connected to the inlet of the secondary blower 2, and the fourth path is connected to the inlet of the primary blower 3.

[0036] In this embodiment, a water coal slurry gasification device 10 is introduced. Using liquid fuel, compared with ordinary solid fuels (such as pulverized coal, biomass powder, etc.), water coal slurry is a deeply clean coal-based liquid fuel with stable combustion, less pollution emissions, much easier feeding and accurate metering to an external combustion furnace. The combustibles in it have a high combustion efficiency, a large heat supplement per unit fuel, save fuel consumption, and produce extremely low harmful gases to the atmosphere during combustion.

[0037] Example 4 On the basis of Example 1, the water coal slurry storage hopper 12 is connected to the feed inlet of the water coal slurry gasification device 10 after passing through the regulating valve V9 and the water coal slurry metering device 15 in sequence. The ignition air duct 11 communicates with the feed inlet of the water coal slurry gasification device 10.

[0038] Three temperature sensors are evenly arranged inside the combustion chamber to monitor the temperature of the combustion chamber, calculate the average temperature of the combustion chamber, and use it as a control parameter of the control system. A gas full-component analyzer is set at the outlet of the mixer to monitor the composition of the raw gas entering the regenerative oxidation device. A water coal slurry metering device 15 is set on the water coal slurry feed pipeline to control the combustion intensity of the water coal slurry gasification device 10.

[0039] In this example, during the operation of the device, when the coal type of the water coal slurry is selected, the consumption of the water coal slurry has a linear relationship with the required amount of syngas. The required amount of syngas is calculated according to the amount and concentration of the wind-discharged gas and is measured by the flowmeter after the regulating valve V8. Therefore, the indication of the water coal slurry metering device 15 is related to the flowmeter after V8, and the supply amount of the water coal slurry is accurately controlled in this way to save fuel.

[0040] Example 5 The multi-medium mixed combustion wind-discharged gas oxidation method using water coal slurry syngas for energy supplement of the present invention is specifically implemented according to the following steps: The wind-discharged gas is divided into 4 paths: (1) The first path of vented gas and the cooled coal water slurry synthesis gas (from the shunt at the outlet of the flame arrester 5) are mixed in the mixer 1 to adjust the calorific value of the vented gas. After the calorific value of the vented gas is adjusted, it enters the regenerative heat oxidizer 13 through the cut-off valve group and into the regenerator of one of the oxidation beds, where it is preheated to about 550 °C. It continues to absorb heat in the combustion chamber and then undergoes an oxidation reaction, generating a large amount of heat. A part of the high-temperature flue gas generated in the combustion chamber recovers heat through the regenerator of the other oxidation bed of the regenerative heat oxidizer 13 and then enters the chimney for evacuation. Another part of the high-temperature flue gas is extracted from the regulating valve V4 at the top of the regenerative heat oxidizer 13 and enters the waste heat boiler 7 to produce steam, providing heat for heat users (power generation, building heating, shaft anti-freezing, coal slime drying, absorption refrigeration, etc.). The flue gas coming out of the waste heat boiler 7 preheats the vented gas through the low-temperature economizer 6 and then enters the chimney.

[0041] (2) The second path of vented gas is pressurized by the primary fan 3 and heated by the low-temperature economizer 6 respectively, and then enters the coal water slurry gasification device 10 and the ignition air duct 11 as the combustion-supporting gas of the coal water slurry gasification device.

[0042] (3) The third path of vented gas is pressurized by the secondary fan 2 and heated by the low-temperature economizer 6 respectively, and then enters the recuperator 16 to recover the heat of the synthesis gas, and then evenly enters the furnace of the coal water slurry gasification device 10 as the combustion-supporting gas of the coal water slurry gasification device.

[0043] (4) The fourth path of vented gas sequentially passes through the regulating valve V3 and the roots blower 8 and enters the loop feeder 14, where it is mixed with the solid particles coming down from the dust collector 9 and then enters the furnace of the coal water slurry gasification device 10.

[0044] The coal water slurry raw material in the coal water slurry storage hopper 12 enters the coal water slurry gasification device 10 after passing through the coal water slurry metering device 15, burns in the furnace after being mixed with the vented gas coming from the secondary fan 2, and the coal water slurry gasification product (synthesis gas) removes solid particles through the dust collector 9, recovers heat through the recuperator 16, and then passes through the flame arrester and is divided into two paths: one path passes through the regulating valve V8 and the flowmeter and then enters the mixer to adjust the calorific value of the vented gas; one path passes through the regulating valve V7 and then enters the synthesis gas burner 4 as the start-up heat source of the regenerative heat oxidizer and the heat source for maintaining the temperature of the combustion chamber and the regenerator during operation. After burning through the synthesis gas burner 4, it heats the gas in the internal space of the combustion chamber, keeps the average temperature of the combustion chamber above the temperature required for the full combustion of the gas, and increases the temperature of the regenerator close to the combustion chamber, maintaining the temperature gradient between the upper and lower parts of the regenerator within the operating range.

[0045] The readings of the gas full-component analyzer at the outlet of mixer 1 are fed back to control system 17. After receiving the reading signal of this gas full-component analyzer, control system 17 controls the opening degrees of regulating valves V1, V2, and V8. Specifically: (1) When the volume fraction of hydrogen in the readings of the gas full-component analyzer is greater than 0.5% or the volume fraction of carbon monoxide is greater than 1%, the opening degree of V8 is reduced to lower the volume fractions of the above-mentioned hydrogen and carbon monoxide; (2) When the volume fraction of hydrogen in the readings of the gas full-component analyzer is greater than 1% or the volume fraction of carbon monoxide is greater than 2%, V2 is closed to strictly prohibit the mixed gas from entering the regenerative oxidation device 13 through V2; (3) When the volume fraction of methane in the readings of the gas full-component analyzer is greater than 1.5%, V2, V1, V3, V5, and V6 are closed to strictly prohibit the mixed gas from entering the regenerative oxidation device 13 through V2.

[0046] The readings of the flow meters on the two inlet pipes of mixer 1 (respectively arranged behind regulating valves V1 and V8) are fed back to control system 17. After receiving the reading signal of this gas full-component analyzer, control system 17 controls the opening degree of regulating valve V8 to control the flow rate of the syngas entering the mixer, thereby controlling the equivalent methane concentration of the mixed gas at the outlet of the mixer. ; The flow rate Q of the syngas sg is calculated according to the following formula:

[0047] In the formula: ——The flow rate of the syngas, Nm 3 / h; ——The flow rate of the air-drained gas, monitored by the gas flow meter behind regulating valve V1, Nm 3 / h; ——The equivalent methane volume concentration after mixing, 0.4% - 1.0%, not exceeding 1.5% at most, preset in control system 17 according to the stable operation of the regenerative oxidation device and the set value is displayed online; ——The methane concentration of the air-drained gas, detected in real time by the online gas sensor at the return air shaft, and this value is uploaded to control system 17; ——The low calorific value of the syngas, detected in real time from the physical properties of the syngas, and this monitored value is uploaded to control system 17, MJ / Nm 3 .

[0048] Example 6 Based on Example 5, Control system 17 controls the flow rate of the air-drained gas entering the Roots blower 8 through regulating valve V3 to keep the height of the solid particles in the return feeder 14 within a certain range.

[0049] The control system 17 controls the flow rate of the vent gas used as the combustion-supporting gas entering the coal water slurry gasification device 10 through the regulating valves V6 and V5. The control system 17 controls the flow rate of the coal water slurry entering the coal water slurry gasification device 10 through the regulating valve V9. By adopting the above control, the combustion intensity of the coal water slurry is maintained, and the flow rate of the syngas entering the mixer 1 through V8 and the flow rate of the syngas entering the syngas burner 4 through V7 are ensured, and finally the average temperature of the combustion chamber is ensured.

[0050] The control system 17 controls the amount of high-temperature flue gas extracted from the top of the combustion chamber through the regulating valve V4, so that the average temperature of the combustion chamber is maintained at 750 °C to 950 °C. When the average temperature of the combustion chamber increases to 950 °C, the regulating valves V3, V5, V6, and V7 are closed, and the regulating valve V4 is kept open to appropriately reduce the average temperature of the combustion chamber. When the average temperature of the combustion chamber drops below 750 °C, the regulating valves V3, V5, V6, and V7 are opened simultaneously, and the regulating valve V4 is closed to appropriately increase the average temperature of the combustion chamber. After the regulating valve V4 is closed, when the average temperature of the combustion chamber increases to 820 °C, the regulating valve V4 is opened. Thus, by adjusting the opening degrees of the above valves, the average temperature of the combustion chamber is maintained at about 900 °C.

[0051] By adopting the above control method, when the raw material gas supplied to the regenerative thermal oxidation device is only the vent gas with a very low methane concentration, the heat generated by its oxidation is not enough to maintain the autothermal balance of the regenerative thermal oxidation device. At this time, the coal water slurry gasification device can use the syngas to mix with the vent gas to increase the calorific value of the gas entering the regenerator of the regenerative thermal oxidation device, increase the heat output after oxidation, so that the temperature of the oxidation device is maintained within the range of autothermal balance, enabling its continuous reaction and reducing methane emissions.

[0052] Compared with directly mixing and supplementing heat with the high-temperature flue gas of a coal-fired furnace directly provided to the combustion chamber, the present invention can prevent the dilution of the gas supplied to the regenerative thermal oxidation device by the heat-supplementing gas, thereby avoiding further reduction of the methane concentration in the raw material gas with an extremely low concentration of gas, and saving the energy-supplementing fuel. The above method can also avoid the interruption of heat supply to heat users, reduce the risk of heat interruption, and reduce the operation cost and safety risk of the device.

[0053] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement without departing from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A multi-media mixed combustion and air exhaust gas oxidation device using water-coal slurry synthesis gas as energy supplement, characterized in that: The invention comprises a water-coal slurry gasification device (10) and a thermal storage oxidation device (13), wherein a regenerator (16) is connected between the water-coal slurry gasification device (10) and the thermal storage oxidation device (13); a secondary fan (2) is connected to the water-coal slurry gasification device (10) via a low-temperature energy saver (6) and the regenerator (16); a primary fan (3) is connected to an ignition air duct (11) of the water-coal slurry gasification device (10) via a low-temperature energy saver (6); the water-coal slurry gasification device (10) is connected to a mixer (1); the thermal storage oxidation device (13) is connected to a waste heat boiler (7); and a control system (17) is further provided, wherein the control system (17) is used to control valves on various connecting pipelines to achieve flow regulation.

2. The multi-media mixed combustion and air exhaust gas oxidation device using water-coal slurry synthesis gas energy supplement according to claim 1 is characterized in that: The water-coal slurry gasification device (10) is connected to a water-coal slurry storage funnel (12). The thermal storage oxidation device (13) comprises a combustion chamber and a thermal storage body. The thermal storage bodies are provided in at least two groups and are arranged at intervals. A synthesis gas burner (4) is provided in the combustion chamber.

3. The multi-media mixed combustion air exhaust gas oxidation device using water-coal slurry synthesis gas energy supplement according to claim 2 is characterized in that: A dust collector (9) is also connected between the regenerator (16) and the water-coal slurry gasification device (10), the dust collector (9) is connected to the material return device (14), and the material return device (14) is connected to the Roots blower (8); a flame arrester (5) is also provided on the connecting pipeline between the regenerator (16) and the synthesis gas burner (4); the water-coal slurry synthesis gas coming out of the flame arrester (5) is divided into two paths, one of which is connected to the inlet of the synthesis gas burner (4) through a regulating valve V7, and the other of which is connected to the mixer (1) through a regulating valve V8. A gas flow meter for detecting the flow rate of the synthesis gas is provided at the inlet end of the mixer (1).

4. The multi-media mixed combustion air exhaust gas oxidation device using water-coal slurry synthesis gas energy supplement according to claim 3 is characterized in that: The outlet of the mixer (1) is connected to the heat storage body of the thermal storage oxidation device (13) through a cut-off valve group, the high-temperature flue gas outlet at the top of the thermal storage oxidation device (13) is connected to the heat source inlet of the waste heat boiler (7) through a regulating valve V4, the heat source outlet of the waste heat boiler (7) is connected to the hot fluid inlet of the low-temperature economizer (6), and the hot fluid outlet of the low-temperature economizer (6) is connected to the chimney.

5. The multi-media mixed combustion air exhaust gas oxidation device using water-coal slurry synthesis gas energy supplement according to claim 4 is characterized in that: The outlets of the secondary fan (2) and the primary fan (3) are connected to two cold fluid inlets of the low-temperature economizer (6) through regulating valves V5 and V6 respectively; one cold fluid pipeline from the secondary fan of the low-temperature economizer (6) is connected to the cold fluid inlet of the regenerator (16), and the other cold fluid pipeline from the primary fan is connected to the ignition air duct (11) of the water-coal slurry gasification device (10).

6. The multi-media mixed combustion air exhaust gas oxidation device using water-coal slurry synthesis gas energy supplement according to claim 3 is characterized in that: The cold fluid outlet of the regenerator (16) is connected to the furnace of the water-coal slurry gasification device (10), the hot fluid inlet of the regenerator (16) is connected to the gas outlet of the dust collector (9), and the hot fluid outlet of the regenerator (16) is connected to the inlet of the flame arrester (5); The ignition air duct (11) is in communication with a feed inlet of a water-coal slurry gasification device (10); the water-coal slurry storage funnel (12) is connected to the feed inlet of the water-coal slurry gasification device (10) after passing through a regulating valve V9 and a water-coal slurry metering device (15) in sequence.

7. The multi-media mixed combustion air exhaust gas oxidation device using water-coal slurry synthesis gas energy supplement according to claim 2 is characterized in that: Three temperature sensors are evenly arranged inside the combustion chamber to monitor the temperature of the combustion chamber; a gas full-component analyzer is arranged at the outlet of the mixer (1) to monitor the composition of the raw gas entering the thermal storage oxidation device.

8. A multi-media mixed combustion air exhaust gas oxidation method using water-coal slurry synthesis gas energy supplementation, characterized in that: The exhaust gas oxidation device according to any one of claims 1 to 7 is used, specifically as follows: The exhaust gas is divided into four routes: the exhaust gas in the first route is mixed with the cooled water-coal slurry synthesis gas and then enters the thermal storage oxidation device, part of the heat is recovered by the thermal storage body, and the other part of the heat enters the waste heat boiler to produce steam and provide heat for heat users; The second exhaust gas is pressurized by the primary fan and heated by the low-temperature economizer before entering the water-coal slurry gasification device and the ignition air duct to serve as the combustion-supporting gas for the water-coal slurry gasification device; The third exhaust gas is pressurized by the secondary fan and heated by the low-temperature economizer, then enters the regenerator to recover the heat of the synthesis gas, and then evenly enters the furnace of the water-coal slurry gasification device as the combustion-supporting gas of the water-coal slurry gasification device; The fourth exhaust gas passes through the regulating valve V3 and the Roots blower in turn and enters the return device. After mixing with the solid particles coming down from the dust collector, it enters the furnace of the water-coal slurry gasification device.

9. The multi-media mixed combustion air exhaust gas oxidation method using water-coal slurry synthesis gas energy supplementation according to claim 8 is characterized in that: The first exhaust gas and the cooled water-coal slurry synthesis gas are mixed in the mixer 1 to adjust the calorific value of the exhaust gas; after the calorific value of the exhaust gas is adjusted, it enters the heat storage body of one of the oxidation beds of the thermal storage oxidation device through the cut-off valve group, is preheated to 550℃±25℃, continues to absorb heat in the combustion chamber and then undergoes oxidation reaction, and generates a large amount of heat; a part of the high-temperature flue gas generated in the combustion chamber recovers heat through the heat storage body of another oxidation bed of the thermal storage oxidation device, and then enters the chimney for discharge, and the other part of the high-temperature flue gas is extracted from the regulating valve V4 at the top of the thermal storage oxidation device and enters the waste heat boiler to produce steam to provide heat for heat users. The flue gas coming out of the waste heat boiler preheats the exhaust gas through the low-temperature economizer and then enters the chimney.

10. The multi-media mixed combustion air exhaust gas oxidation method using water-coal slurry synthesis gas energy supplementation according to claim 8, characterized in that: The specific method of controlling by using the control system is as follows: The reading of the gas full component analyzer at the mixer outlet is fed back to the control system, and the control system controls the opening of the regulating valves V1, V2 and V8 after receiving the reading signal of the gas full component analyzer; specifically: (1) When the hydrogen volume fraction in the gas full component analyzer reading is greater than 0.5% or the carbon monoxide volume fraction is greater than 1%, reduce the V8 opening to reduce the volume fractions of hydrogen and carbon monoxide; (2) When the hydrogen gas integral fraction in the reading of the gas full component analyzer is greater than 1% or the carbon monoxide volume fraction is greater than 2%, close the regulating valve V2, and it is strictly forbidden for the mixed gas to enter the thermal storage oxidation device through the regulating valve V2; (3) When the volume fraction of methane in the reading of the gas full component analyzer is greater than 1.5%, close the regulating valves V2, V1, V3, V5, and V6, and it is strictly forbidden for the mixed gas to enter the thermal oxidation device through the regulating valve V2; The readings of the flow meters on the two inlet pipes of the mixer are fed back to the control system. The control system controls the opening of the regulating valve V8 according to the reading signals to control the flow of the synthesis gas entering the mixer, thereby controlling the equivalent methane concentration of the mixed gas at the mixer outlet. ; Synthesis gas flow rate Q sg Calculate as follows: Where: ——Synthesis gas flow rate, Nm 3 / h; ——The flow rate of exhaust gas is monitored by the flow meter after the regulating valve V1, Nm 3 / h; ——Equivalent methane volume concentration after mixing, ranging from 0.4% to 1.0%; ——methane concentration in exhaust gas; ——Low calorific value of synthesis gas, MJ / Nm 3 ; The control system controls the flow of exhaust gas entering the Roots blower through the regulating valve V3 to maintain the height of solid particles in the return feeder; The control system controls the flow of exhaust gas as combustion-supporting gas entering the water-coal slurry gasification device through regulating valves V6 and V5. The control system controls the flow of water-coal slurry entering the water-coal slurry gasification device through regulating valve V9. The above control is used to maintain the combustion intensity of the water-coal slurry, ensure the flow of synthesis gas entering the mixer through regulating valve V8 and the flow of synthesis gas entering the synthesis gas burner through regulating valve V7, and finally ensure the average temperature of the combustion chamber; The control system controls the amount of high-temperature flue gas extracted from the top of the combustion chamber through the regulating valve V4, so that the average temperature of the combustion chamber is maintained at 750℃~950℃; When the average temperature of the combustion chamber increases to 950°C, close the regulating valves V3, V5, V6, and V7, and keep the regulating valve V4 open to reduce the average temperature of the combustion chamber; when the average temperature of the combustion chamber drops below 750°C, open the regulating valves V3, V5, V6, and V7 at the same time, and close the regulating valve V4 to increase the average temperature of the combustion chamber; after the regulating valve V4 is closed, when the average temperature of the combustion chamber increases to 820°C, open the regulating valve V4; in this way, by adjusting the opening of the above valves, the average temperature of the combustion chamber is maintained at 750°C~950°C.

Images