A system and method for co-oxidative utilization of low-concentration gas containing gas in a regenerator circulation fluidized state

Abstract

A system and method for synergistic oxidation and utilization of low-concentration gas containing gas with a regenerator circulation, belonging to the fields of environmental pollution control, safety technology and engineering. The present invention uses granular regenerators to conduct counter-flow heat exchange with the gas containing gas to achieve fluidized oxidation of the gas containing gas, realizes the circulation of the regenerator particles through a mechanical lifting device, and extracts the oxidation heat of the gas containing gas through a multi-stage heat exchanger. The present invention solves the problem of large bed temperature fluctuations caused by the necessary periodic commutation when fixed regenerators oxidize the gas containing gas, and is particularly suitable for ultra-low concentration VOC gases such as low-concentration gas (1% - 6%) extracted from coal mines, ventilation gas ≤ 1%, and gas containing gas with a gas concentration less than 6% in oil and gas. This method has the characteristics of energy conservation, high efficiency, compact equipment structure, convenient operation, low investment and operation costs, and is conducive to the large-scale of oxidation devices.

Description

Technical Field

[0001] The present invention belongs to the technical fields of environmental pollution control, coal mine safety technology and engineering, and particularly relates to a regenerator circulating type low-concentration gas containing gas fluidized co-oxidation utilization system and a using method thereof. Background Art

[0002] Low-concentration gas is coalbed methane with a methane concentration lower than 30%, which is divided into ventilation-exhausted gas, also known as exhausted air, and extracted gas. Among them, exhausted air gas is coal mine gas with a methane concentration lower than 0.75%.

[0003] At present, most of the extracted gas with a methane concentration lower than 10% is directly discharged. Only a very small number of coal mines oxidize a part of the low-concentration gas through a thermal countercurrent oxidation device. However, there are many problems with this oxidation treatment method. The main problems are that the bed temperature fluctuates greatly, the system device is complicated, and the increase in moving parts makes it easy to malfunction during on-site operation. In addition, when the device is enlarged, the gas flow distribution inside the device is uneven, which easily leads to gas accumulation and poses a great safety hazard. Summary of the Invention

[0004] Technical problems to be solved: Aiming at the deficiencies of the prior art, the present invention provides a regenerator circulating type low-concentration gas containing gas fluidized co-oxidation utilization system and a using method thereof. The invention solves the problem that the fixed regenerator causes large bed temperature fluctuations due to periodic commutation when oxidizing gas containing gas, and is particularly suitable for coal mine extracted low-concentration gas (1% - 6%), ventilation gas (≤1%) and ultra-low-concentration VOC gases such as oil and gas with a gas concentration less than 6%. This method has the characteristics of energy saving, high efficiency, compact equipment structure, convenient operation, low investment and operation costs, and is conducive to the enlargement of the oxidation device.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A system and method for fluidized co-oxidation utilization of low-concentration gas containing gas with regenerator circulation: The system for fluidized co-oxidation utilization of low-concentration gas containing gas with regenerator circulation includes an oxidation device body, a tail flue, and an induced draft system connected in sequence. A wind distribution plate is installed below the oxidation device body, and the wind distribution plate and the bottom plate of the oxidation device body together form an air chamber; a gas containing gas inlet and a start burner are installed on the bottom plate; elevators are vertically installed around the oxidation device body, and a sealing shell is installed outside the elevators; the bottom end of the elevator communicates with the discharge port, and the upper end of the elevator communicates with the return port; a superheater is arranged in the upper space of the oxidation device body; a steam generator and an intake air preheater are arranged in sequence along the flue gas flow direction in the tail flue; the working medium used for heat extraction by the oxidation device body enters from the working medium inlet of the boiler drum, the boiler drum working medium outlet is connected to the steam generator inlet of the steam generator, the steam generator outlet of the steam generator is connected to the steam inlet of the boiler drum, the steam outlet of the boiler drum is connected to the superheater inlet, and the superheater outlet is connected to the steam user inlet; air and high-concentration gas are simultaneously mixed in proportion by a proportioning mixer and then enter the start burner; the low-concentration gas containing gas inlet is connected to the intake air preheater inlet of the intake air preheater, and the intake air preheater outlet of the intake air preheater is connected to the gas containing gas inlet.

[0007] Further, the oxidation device body is of a square structure, and the elevators are evenly arranged around the oxidation device body.

[0008] Further, the regenerator is a granular inert medium, and the granular inert medium is made of aluminum oxide, cordierite, or mullite.

[0009] Further, the working medium is water or an organic working medium.

[0010] Further, a number of small holes are evenly opened on the wind distribution plate.

[0011] Further, wind caps are provided at the orifices of the small holes.

[0012] Further, the wind distribution plate is arranged to slope towards the discharge ports around at an angle of 5-20°.

[0013] A method for using a system for fluidized co-oxidation utilization of low-concentration gas containing gas with regenerator circulation includes the following steps:

[0014] a. The air and high-concentration gas are simultaneously mixed in proportion by a proportioning mixer and then enter the start burner. After being ignited, they enter the air chamber, flow evenly through the wind distribution plate, and then enter the packed bed of regenerator particles and flow upward to heat the packed bed to start combustion; then pass through the tail flue and finally be discharged through the induced draft system;

[0015] b. The low-concentration gas containing gas enters the intake air preheater through the inlet, enters the gas chamber through the gas inlet containing gas, is evenly distributed by the air distribution plate and then enters the heat storage body particle packed bed for oxidation combustion, passes through the tail flue, and finally is discharged through the induced draft system;

[0016] c. The bottom end of the elevator is communicated with the discharge port, and the heat storage body particles are lifted upward under the action of the elevator and then enter the upper part of the heat storage body packed bed through the return port;

[0017] d. The working medium enters through the working medium inlet of the drum, passes through the working medium outlet of the drum and enters the steam generator arranged in the tail flue, passes through the steam outlet of the drum and enters the superheater arranged in the tail flue, and finally enters the steam user inlet through the superheater outlet.

[0018] The present invention provides a heat storage body circulation type low-concentration gas containing gas fluidized co-oxidation utilization system and a use method. Compared with the prior art by adopting the above technical solutions, the following technical effects are achieved:

[0019] 1. The air and the high-concentration gas in the present invention enter the start burner after passing through the proportional mixer at the same time, are ignited and then enter the gas chamber, are evenly distributed by the air distribution plate and then enter the packed body of the heat storage body particles to flow upward to heat the packed bed for starting combustion; this starting method has the advantages of a large heating range, a long service life, and a short starting time compared with the conventional method of using electric heating.

[0020] 2. The superheater, steam generator, and intake air preheater arranged in the tail flue of the present invention can fully utilize the heat generated by oxidation combustion from high grade to low grade. On the one hand, the grade of the recovered heat is improved, and on the other hand, the intake air temperature of the low-concentration gas is increased, thereby improving the combustion efficiency and greatly reducing the exhaust gas temperature.

[0021] 3. The bottom end of the elevator in the present invention is communicated with the discharge port, and the heat storage body particles are lifted upward under the action of the elevator and then enter the upper part of the heat storage body packed bed through the return port; the external lifting device will transport the low-temperature heat storage body particles at the bottom of the packed bed to the top of the packed bed, and by controlling the lifting rate, the high-temperature combustion zone can be stabilized inside the packed bed, greatly improving the stability of the oxidation combustion of the lower-concentration gas. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of a heat storage body circulation type gas containing gas fluidized co-oxidation utilization system.

[0023] Description of reference numerals in the drawings: 1. Oxidation device body; 2. Tail flue; 3. Induced draft system; 4. Air distribution plate; 5. Bottom plate; 6. Air chamber; 7. Inlet for gas containing methane; 8. Ignition burner; 9. Hoist; 10. Discharge port; 11. Sealing housing; 12. Return port; 13. Upper space; 14. Superheater; 15. Steam generator; 16. Inlet air preheater; 17. Working medium; 18. Steam drum; 19. Inlet for working medium; 20. Outlet of working medium from steam drum; 21. Inlet of steam generator; 22. Outlet of steam generator; 23. Steam inlet; 24. Steam outlet; 25. Inlet of superheater; 26. Outlet of superheater; 27. Inlet of steam user; 28. Air; 29. High-concentration methane; 30. Proportion mixer; 31. Inlet for low-concentration gas containing methane; 32. Inlet of inlet air preheater; 33. Outlet of inlet air preheater. Detailed implementation mode

[0024] The present invention will be further described in detail below with reference to the drawings.

[0025] Example: Refer to Figure 1, a heat storage body circulating low-concentration gas containing methane fluidized co-oxidation utilization system, which consists of an oxidation device body 1, a tail flue 2 and an induced draft system 3 connected in sequence. A wind distribution plate 4 is installed below the oxidation device body 1, and the wind distribution plate 4 and the bottom plate 5 of the oxidation device body 1 together form an air chamber 6; a methane-containing gas inlet 7 and a start-up burner 8 are installed on the bottom plate 5; elevators 9 are vertically installed around the oxidation device body 1. The oxidation device body 1 is of a square structure, and the elevators 9 are evenly arranged around the oxidation device body 1. A sealing shell 11 is installed outside the elevators 9; the bottom end of the elevator 9 communicates with the discharge port 10, and the upper end of the elevator 9 communicates with the return port 12; a superheater 14 is arranged in the upper space 13 of the oxidation device body 1; a steam generator 15 and an intake air preheater 16 are arranged in sequence along the flue gas flow direction in the tail flue 2; the working medium 17 used for heat extraction of the oxidation device body 1 enters from the working medium inlet 19 of the boiler drum 18. The working medium 17 is water or an organic working medium. The boiler drum working medium outlet 20 is connected to the steam generator inlet 21 of the steam generator 15. The steam generator outlet 22 of the steam generator 15 is connected to the steam inlet 23 of the boiler drum 18. The steam outlet 24 of the boiler drum 18 is connected to the superheater inlet 25. The superheater outlet 26 is connected to the steam user inlet 27; air 28 and high-concentration methane 29 enter the start-up burner 8 after passing through the proportion mixer 30 at the same time; the low-concentration methane-containing gas inlet 31 is connected to the intake air preheater inlet 32 of the intake air preheater 16, and the intake air preheater outlet 33 of the intake air preheater 16 is connected to the methane-containing gas inlet 7. The heat storage body is a granular inert medium, and the granular inert medium is made of aluminum oxide, cordierite, and mullite. A number of small holes are evenly opened on the wind distribution plate 4, and wind caps are provided at the orifices of the small holes. The wind distribution plate 4 slopes towards the surrounding discharge ports 10 at an angle of 5-20°.

[0026] First, start the induced draft system 3, and then introduce air 28 and high-concentration methane 29 into the start-up burner 8 after passing through the proportion mixer 30 at the same time. After ignition, it enters the air chamber 6, flows evenly through the wind distribution plate 4, and then enters the packed bed of heat storage body particles and flows upward to heat the packed bed of heat storage body to be evenly heated to a temperature of 700-900 °C for start-up combustion; then it passes through the tail flue 2 and finally is discharged through the induced draft system 3.

[0027] After the start-up heating is completed, the low-concentration methane-containing gas enters the intake air preheater 16 through the inlet 31, is preheated, then enters the air chamber 6 through the methane-containing gas inlet 7, flows evenly through the wind distribution plate 4, enters the packed bed of heat storage body particles for oxidation combustion, then passes through the tail flue 2, and finally is discharged through the induced draft system 3.

[0028] The bottom heat storage body particles are lifted upward under the action of the elevator 9, and then enter the upper part of the heat storage body filling bed through the return port 12. In order to stabilize the high-temperature area inside the heat storage body filling bed, it is controlled by controlling the lifting speed of the elevator 9.

[0029] After the combustion is stable, the working medium 17 enters from the working medium inlet 19 of the boiler drum 18, passes through the boiler drum working medium outlet 20 and enters the steam generator 15 arranged in the tail flue 2, passes through the steam outlet 24 of the boiler drum 19 and enters the superheater 14 arranged in the tail flue 2, and finally enters the steam user inlet 27 through the superheater outlet 26.

[0030] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any change or replacement that can be thought of without creative work should be covered within the protection scope of the present invention.

Claims

1. A heat storage body circulation type fluidized bed co-oxidation utilization system for low-concentration gas containing gas, characterized in that: The regenerator cyclic low-concentration gas containing methane fluidized co-oxidation utilization system comprises an oxidation device body (1), a tail flue (2) and an induced draft system (3) which are connected in sequence. A wind distribution plate (4) is installed below the oxidation device body (1). The wind distribution plate (4) and the bottom plate (5) of the oxidation device body (1) together form an air chamber (6); A methane-containing gas inlet (7) and a start-up burner (8) are installed on the bottom plate (5); Hoists (9) are vertically installed around the oxidation device body (1), and a sealing shell (11) is installed outside the hoists (9); The bottom end of the hoist (9) communicates with a discharge port (10), and the upper end of the hoist (9) communicates with a return port (12); A superheater (14) is arranged in the upper space (13) of the oxidation device body (1); A steam generator (15) and an air intake preheater (16) are arranged in the tail flue (2) in sequence along the flue gas flow direction; The working medium (17) used for heat extraction of the oxidation device body (1) enters from the working medium inlet (19) of the boiler drum (18). The boiler drum working medium outlet (20) is connected to the steam generator inlet (21) of the steam generator (15). The steam generator outlet (22) of the steam generator (15) is connected to the steam inlet (23) of the boiler drum (18). The steam outlet (24) of the boiler drum (18) is connected to the superheater inlet (25). The superheater outlet (26) is connected to the steam user inlet (27); Air (28) and high-concentration methane (29) enter the start-up burner (8) after passing through a proportioning mixer (30) at the same time; The low-concentration methane-containing gas inlet (31) is connected to the air intake preheater inlet (32) of the air intake preheater (16). The air intake preheater outlet (33) of the air intake preheater (16) is connected to the methane-containing gas inlet (7); The regenerator is a granular inert medium, and the granular inert medium is made of aluminum oxide, cordierite and mullite.

2. The fluidized bed co-oxidation utilization system for low-concentration gas containing gas with a heat storage body circulation according to claim 1, wherein: The oxidation device body (1) is of a square structure, and the hoists (9) are evenly arranged around the oxidation device body (1).

3. A system for co-oxidative utilization of low-concentration gas containing gas in a fluidized state with a heat storage body circulation, according to claim 1, characterized in that: The working medium (17) is water or an organic working medium.

4. A regenerator cycle type low-concentration gas containing methane fluidized collaborative oxidation utilization system according to claim 1, characterized in that: A number of small holes are evenly formed in the wind distribution plate (4).

5. A regenerator circulation type low-concentration gas-containing gas fluidized co-oxidation utilization system according to claim 4, characterized in that: Wind caps are arranged at the orifices of the small holes.

6. The fluidized bed co-oxidation utilization system for low-concentration gas containing gas with a regenerator cycle according to claim 1, wherein: The wind distribution plate (4) is arranged to slope towards the surrounding discharge ports (10) at an angle of 5-20°.

7. A method for using the system for co-oxidative utilization of low-concentration gas containing gas in a fluidized state with a regenerator circulation, as described in claim 1, characterized in that, The method comprises the following steps: a. First, start the induced draft system (3), and then let air (28) and high-concentration methane (29) enter the start-up burner (8) after passing through a proportioning mixer (30) at the same time. After being ignited, they enter the air chamber (6), flow evenly through the wind distribution plate (4), and then enter the packed bed of regenerator particles and flow upward to heat the packed bed to start combustion; Then it passes through the tail flue (2) and is finally discharged through the induced draft system (3); b. After the start-up heating is completed, the low-concentration methane-containing gas enters the air intake preheater (16) through the inlet (31), is preheated and then enters the air chamber (6) through the methane-containing gas inlet (7), flows evenly through the wind distribution plate (4), enters the packed bed of regenerator particles for oxidation combustion, then passes through the tail flue (2), and is finally discharged through the induced draft system (3); c. The bottom end of the elevator (9) communicates with the discharge port (10), and the regenerator particles are lifted upward under the action of the elevator (9), and then enter the upper part of the regenerator filling bed through the return port (12). d. After the combustion is stable, the working medium (17) enters through the working medium inlet (19) of the boiler drum (18), passes through the boiler drum working medium outlet (20) and enters the steam generator (15) arranged in the tail flue (2), passes through the steam outlet (24) of the boiler drum (19) and enters the superheater (14) arranged in the tail flue (2), and finally enters the steam user inlet (27) through the superheater outlet (26).

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