System and method for coal mine gas carbon reduction and utilization

Abstract

Provided are a system and method for carbon reduction and utilization of coal mine gas. The system includes a low-concentration extracted gas conveying unit, a ventilation gas collection, conveying, and distribution unit, a gas blending unit, a low-concentration extracted gas thermal storage and thermal oxidation unit, a ventilation gas thermal storage and catalytic oxidation unit, an oxidation waste heat comprehensive utilization unit, and an emission unit. The gas blending unit is connected to the low-concentration extracted gas conveying unit and the ventilation gas collection, conveying, and distribution unit; the low-concentration extracted gas thermal storage and thermal oxidation unit is connected to the gas blending unit; the ventilation gas thermal storage and catalytic oxidation unit is connected to the ventilation gas collection, conveying, and distribution unit and the low-concentration extracted gas thermal storage and thermal oxidation unit; and the oxidation waste heat comprehensive utilization unit is connected to the low-concentration extracted gas thermal storage and thermal oxidation unit and the ventilation gas thermal storage and catalytic oxidation unit. By combining a thermal storage oxidation system with a thermal storage and catalytic oxidation system, the system and method can improve the utilization rate of gas oxidation heat energy and achieve low-cost emission reduction of methane in ventilation gas.

Description

Technical Field

[0001] The present invention belongs to the field of carbon emission reduction control, and specifically relates to a system and method for coal mine gas carbon reduction utilization. Background Art

[0002] Methane is the second most potent greenhouse gas globally, with a warming potential 84 times that of carbon dioxide and 28 times that of carbon dioxide, respectively. It is estimated that methane emissions contribute approximately 0.5°C of the 1.1°C global temperature rise above pre-industrial levels. my country is a major methane emitter. According to statistics, in 2020, national methane emissions reached 53.2 million tons, equivalent to approximately 1.49 billion tons of carbon dioxide equivalent, accounting for 10.8% of my country's total greenhouse gas emissions. The coal industry bears the brunt of my country's methane emissions, contributing 21 million tons, or 39% of the national total, far exceeding the emission levels of the United States (7%) and the European Union (9%).

[0003] Compared with the oil and gas industry, the technical difficulty and economic challenges of coal methane emission control are greater, and the comprehensive utilization method is closely related to the methane concentration contained in it. For high-concentration gas (concentration>30%), it is currently mainly used as a chemical raw material and fuel, with high technical maturity and good economic benefits. For low-concentration extracted gas (concentration 9% to 30%), it can be utilized through reciprocating internal combustion engine generator sets, or it can be purified and converted into high-concentration gas for use. For ultra-low concentration extracted gas (concentration 3-9%) and ventilation gas (concentration <0.75%), which account for more than 80% of the total coal mine gas emissions, they cannot be directly burned due to their low concentration and large air-fuel ratio. The current utilization method is to use oxidation technology to oxidize the gas to obtain heat, mainly including thermal storage oxidation technology and thermal storage catalytic oxidation technology.

[0004] Currently, regenerative thermal oxidation (RTO) projects have been established in several coal mines, utilizing gas concentrations of approximately 1.2%. For even lower concentrations, regenerative catalytic oxidation (RTO) technology can be used. This technology, utilizing catalysts to lower the methane oxidation temperature to 400-500°C, simultaneously reduces nitrogen oxide production. This represents a promising development direction for coal mine gas utilization technology in the context of achieving carbon neutrality.

[0005] Traditional ventilation gas is used for separate oxidation to reduce carbon emissions. Due to the low methane concentration in the ventilation gas, it is difficult to stabilize the self-heating balance, and additional energy is needed for heat supplementation, which results in high operating costs. In addition, there is no stable waste heat from the oxidation of ventilation gas for external use, and the economic efficiency of building ventilation gas carbon emission reduction projects is poor. For low-concentration extracted gas, the thermal storage oxidation method is currently used. The low-concentration extracted gas (1.5-9%) is mixed with ventilation gas (<0.75%) to form a 1.2% concentration gas and sent to the thermal oxidation furnace for oxidation treatment. The waste heat from oxidation is used for heating and power generation, mainly for heating in winter and for power generation in summer. However, due to the limitation of the total amount of gas, the economic efficiency of power generation in summer is poor. In addition, in order to match the gas concentration of 1.2% sent to the oxidation system, only a limited volume of ventilation gas can be processed, and most of the remaining ventilation gas is still discharged, which cannot further increase the emission reduction of ventilation gas.

[0006] To this end, there is an urgent need to develop a technical method that can be used for large-scale coal mine gas and methane emission reduction, so as to realize the utilization of the potential thermal energy of gas and increase the carbon emission reduction of coal mines. Summary of the Invention

[0007] A first object of the present invention is to provide a system for reducing carbon in coal mine gas by combining a thermal oxidation system with a catalytic oxidation system.

[0008] The second object of the present invention is to provide a method for reducing carbon emissions from coal mine gas using the aforementioned system, which can improve the utilization rate of gas thermal energy, increase the amount of ventilation gas processed, increase carbon emission reduction, and reduce carbon emission reduction costs.

[0009] In order to achieve the first object of the present invention, the following technical solutions are adopted:

[0010] A system for carbon reduction and utilization of coal mine gas, comprising a low-concentration extracted gas transportation unit, a ventilation gas collection and transportation distribution unit, a gas blending unit, a low-concentration extracted gas heat storage thermal oxidation unit, a ventilation gas heat storage catalytic oxidation unit, an oxidation waste heat comprehensive utilization unit, and an emission unit, all connected by pipelines; wherein,

[0011] The inlet of the gas blending unit is connected to the outlet of the low-concentration extracted gas delivery unit and the exhaust gas collection and delivery distribution unit, respectively, for respectively introducing low-concentration extracted gas and exhaust gas and blending them to obtain blended gas;

[0012] The low-concentration extracted gas heat storage thermal oxidation unit includes a mixed gas inlet, a hot flue gas outlet, and a cooled flue gas outlet, and its mixed gas inlet is connected to the outlet of the gas mixing unit, and is used to perform a thermal oxidation reaction on the mixed gas from the gas mixing unit to obtain thermally oxidized flue gas, a portion of which is cooled by its heat storage body and output through its cooled flue gas outlet, and the rest is directly output through its hot flue gas outlet;

[0013] The exhaust gas thermal storage catalytic oxidation unit includes an exhaust gas inlet, a flue gas inlet, a hot flue gas outlet and a cooling flue gas outlet, and its exhaust gas inlet is connected to the exhaust gas collection and transportation distribution unit for feeding exhaust gas, and its flue gas inlet is connected to the hot flue gas outlet of the low-concentration extracted gas thermal storage thermal oxidation unit for feeding the hot oxidized flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit to auxiliary heat the exhaust gas fed into the exhaust gas thermal storage catalytic oxidation unit for catalytic oxidation reaction to obtain catalytically oxidized flue gas, a part of which is cooled by its heat storage body and then output through its cooling flue gas outlet, and the rest is directly output through its hot flue gas outlet;

[0014] The inlet of the oxidation waste heat comprehensive utilization unit is respectively connected to the hot flue gas outlet of the low-concentration extracted gas heat storage thermal oxidation unit and the exhaust gas heat storage catalytic oxidation unit, and is used to cool down part of the hot oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit and the catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit after utilization, and output the cooled flue gas;

[0015] The inlet of the discharge unit is respectively connected to the cooling flue gas outlets of the low-concentration extracted gas heat storage thermal oxidation unit and the lack of air gas heat storage catalytic oxidation unit and the flue gas outlet of the oxidation waste heat comprehensive utilization unit, and is used to discharge the cooling thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit, the cooling catalytic oxidation flue gas from the lack of air gas heat storage catalytic oxidation unit and the cooling flue gas from the oxidation waste heat comprehensive utilization unit.

[0016] Preferably, the low-concentration extracted gas thermal storage thermal oxidation unit is provided with a thermal storage thermal oxidation chamber, and the exhaust gas thermal storage catalytic oxidation unit is provided with a thermal storage catalytic oxidation chamber, and both ends of the first thermal oxidation flue gas pipeline from the low-concentration extracted gas thermal storage thermal oxidation unit to the exhaust gas thermal storage catalytic oxidation unit are respectively connected to the thermal storage thermal oxidation chamber and the thermal storage catalytic oxidation chamber.

[0017] Preferably, a discharge valve is provided on the first thermal oxidation flue gas pipeline from the low-concentration extracted gas heat storage thermal oxidation unit to the exhaust gas heat storage catalytic oxidation unit to control the flow of materials in the first thermal oxidation flue gas pipeline.

[0018] Preferably, a discharge valve is provided on the second thermal oxidation flue gas pipeline from the low-concentration extracted gas heat storage thermal oxidation unit to the oxidation waste heat comprehensive utilization unit, for controlling the flow of materials in the second thermal oxidation flue gas pipeline.

[0019] Preferably, the emission unit includes a fan and a chimney connected in sequence, and is respectively connected to the cooling flue gas outlets of the low-concentration extracted gas heat storage thermal oxidation unit and the lack-air gas heat storage catalytic oxidation unit and the flue gas outlet of the oxidation waste heat comprehensive utilization unit through the inlet of the fan, so as to use the fan to send the cooling thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit, the cooling catalytic oxidation flue gas from the lack-air gas heat storage catalytic oxidation unit and the cooling flue gas from the oxidation waste heat comprehensive utilization unit into the chimney for emission.

[0020] Preferably, the emission unit also includes a mixing flue, which is arranged at the inlet end of the fan and is used to receive and buffer the cooled thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit and the cooled catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit to supply the fan.

[0021] Preferably, the oxidation waste heat comprehensive utilization unit includes a waste heat boiler and a heat utilization unit connected by pipelines; and the inlet of the waste heat boiler is respectively connected to the flue gas outlets of the low-concentration extracted gas heat storage thermal oxidation unit and the exhaust gas heat storage catalytic oxidation unit, for introducing the thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit and the catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit and utilizing the heat energy therein to produce steam; the heat utilization unit is connected to the steam outlet of the waste heat boiler, for utilizing the steam from the waste heat boiler.

[0022] Preferably, a flue gas conveying pipe is provided from the flue gas outlet of the waste heat boiler to the inlet of the discharge unit, for conveying the flue gas from the waste heat boiler to the discharge unit for discharge.

[0023] Preferably, in the oxidation waste heat comprehensive utilization unit, the heat-using unit includes a heat supply unit and / or a power generation unit, the heat supply unit includes any one or more combinations of mine heating, cooling, and industrial steam, and the power generation unit includes a steam turbine and a generator connected in sequence.

[0024] To achieve the second object of the present invention, a method for utilizing the aforementioned system to reduce carbon emissions from coal mine gas is provided, the method comprising:

[0025] (1) sending the low-concentration drained gas from the low-concentration drained gas delivery unit and the exhaust gas from the exhaust gas collection and delivery distribution unit into the gas blending unit for blending to obtain blended gas;

[0026] (2) The blended gas from the gas blending unit is fed into the low-concentration extracted gas heat storage thermal oxidation unit for thermal oxidation reaction to obtain thermally oxidized flue gas, a portion of which is cooled by the heat storage body and then output through the cooled flue gas outlet, and the remaining portion is directly output through the hot flue gas outlet;

[0027] (3) sending part of the thermally oxidized flue gas from the low-concentration extracted gas heat storage thermal oxidation unit and part of the exhaust gas from the exhaust gas collection and transportation distribution unit into the exhaust gas heat storage catalytic oxidation unit, using part of the thermally oxidized flue gas from the low-concentration extracted gas heat storage thermal oxidation unit (4) to assist part of the exhaust gas from the exhaust gas collection and transportation distribution unit (2) in performing a catalytic oxidation reaction, thereby obtaining catalytically oxidized flue gas, part of which is cooled by its heat storage body and then outputted through its cooling flue gas outlet, and the rest is directly outputted through its hot flue gas outlet;

[0028] (4) sending part of the thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit and / or the catalytic oxidation flue gas from the exhaust gas thermal storage catalytic oxidation unit to the oxidation waste heat comprehensive utilization unit for utilization;

[0029] (5) The cooled thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit and / or the cooled catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit are respectively sent to the emission unit for emission.

[0030] Preferably, the method further comprises:

[0031] In step (3), the discharge valve is used to control the flow of materials in the first thermal oxidation flue gas duct; and / or

[0032] In step (3), the discharge valve is used to control the flow of materials in the second thermal oxidation flue gas duct.

[0033] Preferably, the method further comprises:

[0034] The flue gas from the waste heat boiler is sent to the discharge unit through the flue gas conveying pipeline for discharge.

[0035] The beneficial effects of the present invention are:

[0036] (1) The system and method for coal mine gas carbon reduction and utilization of the present invention achieves full economic carbon reduction of low-concentration coal mine gas and ventilation gas through the combined use of thermal oxidation and catalytic oxidation technology, turning waste into treasure, and obtaining methane energy benefits, thus overcoming the inherent shortcomings of a single technology and giving full play to the combined advantages;

[0037] (2) The system and method for coal mine gas carbon reduction utilization of the present invention fully utilizes the high-quality thermal energy conversion of gas by thermal oxidation and the low construction cost. In combination with the waste heat boiler system, the waste heat of the high-temperature heat source - thermal oxidation flue gas and catalytic oxidation flue gas is utilized to generate steam for external heating, cooling or power generation, thereby achieving gas carbon emission reduction while obtaining energy supply income.

[0038] (3) The system and method for carbon reduction and utilization of coal mine gas of the present invention overcome the shortcoming of large heat energy loss in the thermal storage thermal oxidation unit of low-concentration extracted gas, and send the lost heat and excess heat into the thermal storage catalytic oxidation unit of the exhaust gas through the first thermal oxidation flue gas pipeline and the discharge valve thereon to be utilized, thereby increasing the operating temperature of the catalytic oxidation reaction in the thermal storage catalytic oxidation unit of the exhaust gas and improving the conversion efficiency of the exhaust gas; and when the heating load is small and the power generation efficiency is low in the non-heating season, the heat energy of the thermal storage thermal oxidation unit of the low-concentration extracted gas is mainly sent into the thermal storage catalytic oxidation unit of the exhaust gas to be utilized, further improving the catalytic oxidation processing capacity of the exhaust gas, increasing the carbon emission reduction amount, and increasing the carbon emission reduction benefits through energy cascade utilization;

[0039] (4) The system and method for coal mine gas carbon reduction utilization of the present invention overcome the shortcomings of low gas concentration, large fluctuation, and difficulty in maintaining self-heating balance in a single ventilation gas catalytic oxidation system. By utilizing the heat energy of the low-concentration gas thermal storage thermal oxidation unit, additional energy input is saved, operating costs are reduced, operating temperature is increased, methane oxidation efficiency is improved, and carbon emission reduction of ventilation gas is increased, thereby achieving carbon emission reduction effects and carbon emission reduction benefits;

[0040] (5) The system and method for reducing carbon in coal mine gas of the present invention, the thermal oxidation technology and the catalytic oxidation technology cooperate with each other to make the system operation more flexible, practical, economical, and have good environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of a system for reducing carbon in coal mine gas according to the present invention in one embodiment. DETAILED DESCRIPTION

[0042] The following further describes the technical solutions and effects of the present invention in conjunction with specific embodiments and examples. The following embodiments and examples are intended only to illustrate the present invention and are not intended to be limited to the following embodiments and examples. Simple modifications to the present invention that utilize the concepts of the present invention fall within the scope of protection claimed herein.

[0043] like Figure 1As shown, a system for carbon reduction and utilization of coal mine gas includes a low-concentration extracted gas transportation unit 1, a ventilation gas collection and transportation distribution unit 2, a gas blending unit 3, a low-concentration extracted gas heat storage thermal oxidation unit 4, a ventilation gas heat storage catalytic oxidation unit 6, an oxidation waste heat comprehensive utilization unit and an emission unit connected by pipelines; wherein,

[0044] The inlet of the gas blending unit 3 is connected to the outlet of the low-concentration drained gas delivery unit 1 and the exhaust gas collection and delivery distribution unit 2, respectively, for respectively introducing low-concentration drained gas and exhaust gas and blending them to obtain blended gas;

[0045] The low-concentration extracted gas heat storage thermal oxidation unit 4 includes a mixed gas inlet, a flue gas outlet, and a cooled flue gas outlet, and its mixed gas inlet is connected to the outlet of the gas mixing unit 3, and is used to perform a thermal oxidation reaction on the mixed gas from the gas mixing unit 3 to obtain thermally oxidized flue gas, wherein a portion of the flue gas is cooled by its heat storage body and output through its cooled flue gas outlet, and the remaining portion is directly output through its hot flue gas outlet;

[0046] The exhaust gas thermal storage catalytic oxidation unit 6 includes an exhaust gas inlet, a flue gas inlet, a flue gas outlet and a cooling flue gas outlet, and its exhaust gas inlet is connected to the exhaust gas collection and transportation distribution unit 2 for feeding exhaust gas, and its flue gas inlet is connected to the flue gas outlet of the low-concentration extracted gas thermal storage thermal oxidation unit 4 for feeding the thermally oxidized flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 to auxiliary heat the exhaust gas fed into the exhaust gas thermal storage catalytic oxidation unit (6) (including the exhaust gas from the exhaust gas collection and transportation distribution unit 2) to perform a catalytic oxidation reaction to obtain catalytically oxidized flue gas, a part of which is cooled by its heat storage body and then output through its cooling flue gas outlet, and the rest is directly output through its hot flue gas outlet;

[0047] The inlet of the oxidation waste heat comprehensive utilization unit is respectively connected to the hot flue gas outlet of the low-concentration extracted gas heat storage thermal oxidation unit 4 and the exhaust gas heat storage catalytic oxidation unit 6, and is used to cool down part of the hot oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4 and the catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit 6 after utilization, and output the cooled flue gas;

[0048] The inlet of the discharge unit is respectively connected to the cooling flue gas outlets of the low-concentration extracted gas heat storage thermal oxidation unit 4 and the lack of air gas heat storage catalytic oxidation unit 6, as well as the flue gas outlet of the oxidation waste heat comprehensive utilization unit, for discharging the cooling thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4, the cooling catalytic oxidation flue gas from the lack of air gas heat storage catalytic oxidation unit 6, and the cooling flue gas from the oxidation waste heat comprehensive utilization unit.

[0049] The system for reducing carbon emissions from coal mine gas of the present invention, by combining thermal oxidation with catalytic oxidation, can consume more low-concentration extracted gas and exhaust gas, generate more heat energy, and realize the circulation and effective utilization of heat energy, thereby achieving overall economic carbon emission reduction of low-concentration extracted gas and exhaust gas, turning waste into treasure, and obtaining methane energy benefits, overcoming the shortcomings of a single technology itself and giving full play to the combined advantages; overcoming the shortcomings of large heat energy loss in the thermal storage thermal oxidation unit of low-concentration extracted gas, and utilizing its heat loss and excess heat by sending the heat loss and excess heat into the exhaust gas thermal storage catalytic oxidation unit for utilization, thereby improving the heat energy utilization rate, increasing the operating temperature of the catalytic oxidation reaction in the exhaust gas thermal storage catalytic oxidation unit, and improving the conversion efficiency of exhaust gas.

[0050] Those skilled in the art will understand that the low-concentration extracted gas transportation unit 1 is a low-concentration extracted gas transportation system commonly used in the art, including: an automatic dispersing device, a water-sealed fire-blocking and explosion-proofing device, an automatic explosion-proofing device, an automatic explosive device, an induced draft fan, and pipeline valve instruments and other devices; the exhaust gas collection and transportation distribution unit 2 is a exhaust gas collection and transportation distribution system commonly used in the art, including: an exhaust gas collection hood, a dust and mist removal device, a sewage discharge device, an induced draft fan, and an exhaust gas distribution baffle door and other devices; the gas blending unit 3 is a gas blending system commonly used in the art, including: a gas blender, a detection instrument device, an explosion-proofing device and other devices; the low-concentration extracted gas heat storage thermal oxidation unit 4 is a low-concentration extracted gas thermal oxidation system commonly used in the art (i.e., RT O system), including: a heat storage body, a gas oxidation reactor, a heating start-up device, a flue gas inlet and outlet gas distribution valve, a flue gas exhaust device, a detection instrument, etc., and a heat storage thermal oxidation chamber is provided in the gas oxidation reactor; the exhaust gas heat storage catalytic oxidation unit 6 is a commonly used exhaust gas catalytic oxidation system (i.e., RCO system) in this field, including: a heat storage body, a high-temperature and sulfur-resistant methane oxidation catalyst, a gas oxidation reactor, a flue gas inlet and outlet gas distribution valve, a flue gas exhaust device, a detection instrument, etc., and a heat storage catalytic oxidation chamber is provided in the gas oxidation reactor; the oxidation waste heat comprehensive utilization unit is a commonly used oxidation waste heat comprehensive utilization system in this field, including a waste heat boiler, a steam-water system, a heating pipe, a heat pump system, a heat use system, etc.

[0051] In one embodiment, the low-concentration extracted gas thermal storage thermal oxidation unit 4 is provided with a thermal storage thermal oxidation chamber, and the exhaust gas thermal storage catalytic oxidation unit 6 is provided with a thermal storage catalytic oxidation chamber, and both ends of the first thermal oxidation flue gas pipe 51 from the low-concentration extracted gas thermal storage thermal oxidation unit 4 to the exhaust gas thermal storage catalytic oxidation unit 6 are respectively connected to the thermal storage thermal oxidation chamber and the thermal storage catalytic oxidation chamber.

[0052] Those skilled in the art understand that, as mentioned above, the low-concentration extracted gas thermal storage thermal oxidation unit 4 includes a gas oxidation reactor, and a thermal storage thermal oxidation chamber is provided in the gas oxidation reactor; the exhaust gas thermal storage catalytic oxidation unit 6 includes a gas oxidation reactor, and a thermal storage catalytic oxidation chamber is provided in its gas oxidation reactor; the low-concentration extracted gas thermal storage thermal oxidation unit 4 and the exhaust gas thermal storage catalytic oxidation unit 6 are connected through the connection between the thermal storage thermal oxidation chamber and the thermal storage catalytic oxidation chamber.

[0053] In one embodiment, a discharge valve 511 is provided on the first thermal oxidation flue gas pipe 51 from the low-concentration extracted gas heat storage thermal oxidation unit 4 to the exhaust gas heat storage catalytic oxidation unit 6, which is used to control the flow of materials in the first thermal oxidation flue gas pipe 51, such as cutoff, circulation, flow rate, etc., so as to make adjustments as needed.

[0054] In one embodiment, a discharge valve 521 is provided on the second thermal oxidation flue gas pipeline 52 from the low-concentration extracted gas heat storage thermal oxidation unit 4 to the oxidation waste heat comprehensive utilization unit, which is used to control the flow of materials in the second thermal oxidation flue gas pipeline 52, such as cutoff, circulation, flow rate, etc., so as to make adjustments as needed.

[0055] In one embodiment, the emission unit includes a fan 81 and a chimney 82 connected in sequence, and is respectively connected to the cooling flue gas outlets of the low-concentration extracted gas heat storage thermal oxidation unit 4 and the lack-of-air gas heat storage catalytic oxidation unit 6 and the flue gas outlet of the oxidation waste heat comprehensive utilization unit through the inlet of the fan 81, so as to use the fan 81 to send the cooling thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4, the cooling catalytic oxidation flue gas from the lack-of-air gas heat storage catalytic oxidation unit 6, and the cooling flue gas from the oxidation waste heat comprehensive utilization unit into the chimney 82 for discharge.

[0056] In one embodiment, the emission unit further includes a mixing flue 83, which is arranged at the inlet end of the fan 81, and is used to receive and buffer the cooled thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 and the cooled catalytic oxidation flue gas from the lack of air gas thermal storage catalytic oxidation unit 6 to supply the fan 81, so that the cooled thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 and the cooled catalytic oxidation flue gas from the lack of air gas thermal storage catalytic oxidation unit 6 are buffered before entering the fan 81, thereby avoiding system fluctuations and improving system stability.

[0057] In one embodiment, the oxidation waste heat comprehensive utilization unit includes a waste heat boiler 71 and a heat utilization unit 72 connected by pipelines; and the inlet of the waste heat boiler 71 is respectively connected to the flue gas outlets of the low-concentration extracted gas heat storage thermal oxidation unit 4 and the exhaust gas heat storage catalytic oxidation unit 6, for introducing the thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4 and the catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit 6 and utilizing the heat energy therein to produce steam; the heat utilization unit 72 is connected to the steam outlet of the waste heat boiler 71, for utilizing the steam from the waste heat boiler 71.

[0058] In one embodiment, in the oxidation waste heat comprehensive utilization unit, the heat using unit includes a heat supply unit and / or a power generation unit, the heat supply unit includes any one or more combinations of mine heating, cooling, and industrial steam, and the power generation unit includes a steam turbine and a generator connected in sequence.

[0059] Those skilled in the art will appreciate that corresponding valves are provided on the relevant pipelines of the present invention to control the flow of materials.

[0060] In one embodiment, in the system, the ventilation gas thermal storage catalytic oxidation unit 6 is replaced by a direct catalytic oxidation unit.

[0061] Those skilled in the art understand that the direct catalytic oxidation unit is a direct catalytic oxidation system commonly used in the art (i.e., CO system), which includes: a high-temperature and sulfur-resistant methane oxidation catalyst, a gas oxidation reactor, a flue gas inlet and outlet gas distribution valve, a flue gas heat exchanger, a flue gas exhaust device, detection instruments, etc.

[0062] In one embodiment, the system further includes the direct catalytic oxidation unit, which is arranged in parallel with the exhaust gas thermal storage catalytic oxidation unit 6, and is used to connect the direct catalytic oxidation unit and / or the exhaust gas thermal storage catalytic oxidation unit 6 with the low-concentration extracted gas thermal storage thermal oxidation unit 4, effectively utilizing the thermal energy of the low-concentration extracted gas thermal storage thermal oxidation unit, improving the thermal energy utilization rate, and improving the conversion efficiency of the exhaust gas in the direct catalytic oxidation unit and / or the exhaust gas thermal storage catalytic oxidation unit 6.

[0063] The present invention also provides a method for utilizing the aforementioned system to reduce carbon emissions from coal mine gas, comprising:

[0064] (1) The low-concentration extracted gas from the low-concentration extracted gas delivery unit 1 and part of the exhaust gas from the exhaust gas collection and delivery distribution unit 2 are respectively delivered to the gas blending unit 3 for blending to obtain blended gas;

[0065] (2) The blended gas from the gas blending unit 3 is fed into the low-concentration extracted gas heat storage thermal oxidation unit 4 for thermal oxidation reaction to obtain thermally oxidized flue gas, a portion of which is cooled by the heat storage body and then output through the cooled flue gas outlet, and the remaining portion is directly output through the hot flue gas outlet;

[0066] (3) sending part of the thermally oxidized flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4 and part of the exhaust gas from the exhaust gas collection and transportation distribution unit 2 into the exhaust gas heat storage catalytic oxidation unit 6, using part of the thermally oxidized flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4 to assist in heating part of the exhaust gas from the exhaust gas collection and transportation distribution unit 2 to carry out catalytic oxidation reaction, thereby obtaining catalytically oxidized flue gas, part of which is cooled by its heat storage body and then output through its cooling flue gas outlet, and the rest is directly output through its hot flue gas outlet;

[0067] (4) sending part of the thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 and / or the catalytic oxidation flue gas from the exhaust gas thermal storage catalytic oxidation unit 6 to the oxidation waste heat comprehensive utilization unit for utilization;

[0068] (5) The cooled thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 and / or the cooled catalytic oxidation flue gas from the exhaust gas thermal storage catalytic oxidation unit 6 are respectively sent to the discharge unit for discharge.

[0069] The method of the present invention mainly obtains a mixed gas with a concentration of 1-1.5% by mixing low-concentration extracted gas with part of the exhaust air gas and enters the thermal oxidation (RTO) device in the low-concentration extracted gas heat storage thermal oxidation unit 4 to undergo high-temperature complete oxidation, thereby realizing the cascade utilization of high-grade thermal energy under the exothermic conditions of high-temperature oxidation of methane, which is used for power generation and heat supply, etc., and the high-temperature leaked hot flue gas and high-temperature waste heat of the low-concentration extracted gas heat storage thermal oxidation unit 4 are sent to the catalytic oxidation (RCO) device in the exhaust air gas heat storage catalytic oxidation unit 6 to supplement the heat required for the operation of the RCO device or improve the exhaust air catalytic oxidation efficiency. During operation, the low-concentration extracted gas heat storage thermal oxidation unit 4 and the exhaust air gas heat storage catalytic oxidation unit 6 are operated in parallel. The thermal oxidation reaction of the mixed gas entering the low-concentration extracted gas heat storage thermal oxidation unit 4 does not require the introduction of additional fuel to assist its oxidation. Part of the heat is sent to the exhaust gas heat storage catalytic oxidation unit 6, avoiding the technical difficulties of insufficient calorific value of the exhaust gas itself and the inability to stably operate the exhaust gas heat storage catalytic oxidation alone. It reduces the minimum methane concentration and oxidation temperature for self-sustaining operation, improves the utilization efficiency of the exhaust gas, and solves the problem that the exhaust gas and low-concentration gas in coal mines cannot be directly utilized, effectively solving the contradiction of tight power supply in mining areas and the environmental protection pressure of carbon peak and carbon neutrality.

[0070] In one embodiment, the concentration of the ventilation gas from the ventilation gas collection and transportation distribution unit 2 is 0.05-0.75v%, such as 0.1v%, 0.15v%, 0.2v%, 0.25v%, 0.3v%, 0.35v%, 0.4v%, 0.45v%, 0.5v%, 0.55v%, 0.6v%, 0.65v% and 0.7v%.

[0071] In the present invention, the concentration of ventilation gas refers to the volume concentration of methane in the ventilation gas.

[0072] In one embodiment, the concentration of the low-concentration extracted gas from the low-concentration extracted gas delivery unit 1 is 1.5-9%, such as 2v%, 2.5v%, 3v%, 3.5v%, 4v%, 4.5v%, 5v%, 5.5v%, 6v%, 6.5v%, 7v%, 7.5v%, 8v% and 8.5v%.

[0073] In the present invention, the concentration of low-concentration drained gas refers to the volume concentration of methane in the low-concentration drained gas.

[0074] In one embodiment, in step (1), the blending ratio is controlled so that the concentration of the obtained blended gas is 1-1.5v%, such as 1.1v%, 1.2v%, 1.3v% and 1.4v%.

[0075] In the present invention, the concentration of the mixed gas refers to the volume concentration of methane in the mixed gas.

[0076] In one embodiment, in step (3), the low-concentration extracted gas heat storage thermal oxidation unit 4 is first preheated to 950°C, and then the mixed gas from the gas blending unit 3 is introduced; preferably, when the introduced mixed gas is heated to 900-1000°C (such as 910°C, 920°C, 930°C, 940°C, 950°C, 960°C, 970°C, 980°C and 990°C), a thermal oxidation reaction occurs, and rapid oxidation and heat release begin to be generated, generating high-temperature thermal oxidation flue gas.

[0077] Those skilled in the art understand that during the preheating process of the low-concentration extracted gas heat storage thermal oxidation unit 4, heat energy will be stored in the heat storage body therein, and then the mixed gas from the gas blending unit 3 that is subsequently introduced will be heated.

[0078] In one embodiment, in step (2), the reaction temperature of the thermal oxidation reaction is 900-1000°C, such as 910°C, 920°C, 930°C, 940°C, 950°C, 960°C, 970°C, 980°C and 990°C.

[0079] In one embodiment, in step (2), a portion of the thermal oxidation flue gas is cooled and cooled by its heat storage body and then output through its cooling flue gas outlet, which means that a portion of the thermal oxidation flue gas will be used to heat the cold side heat storage body in the low-concentration extracted gas heat storage thermal oxidation unit 4 to store heat and maintain stable operation of the thermal oxidation device, and then the flue gas itself is cooled and cooled, and the resulting cooled thermal oxidation flue gas is output through its cooling flue gas outlet.

[0080] In one embodiment, in step (3), the exhaust gas thermal storage catalytic oxidation unit 6 is first preheated to 600°C, and then part of the exhaust gas from the exhaust gas collection and transportation distribution unit 2 is introduced; preferably, the heat energy source during its preheating includes part of the thermal oxidation flue gas from the low-concentration gas thermal storage thermal oxidation unit 4; preferably, when the exhaust gas introduced is heated to 350-650°C, a catalytic oxidation reaction of methane occurs, and rapid catalytic oxidation releases heat to generate high-temperature catalytic oxidation flue gas, thereby destroying the gas and reducing methane emissions.

[0081] Those skilled in the art understand that during the preheating process, the heat energy of the ventilation gas heat storage catalytic oxidation unit 6 will be stored in the heat storage body therein, and then the ventilation gas subsequently introduced from the ventilation gas collection and transmission distribution unit 2 will be heated.

[0082] In one embodiment, in step (3), the reaction temperature of the catalytic oxidation reaction is 350-650°C, such as 400°C, 450°C, 500°C, 550°C and 600°C.

[0083] In one embodiment, in step (3), the catalyst for the catalytic oxidation reaction is a sulfur-resistant and high-temperature resistant catalyst, such as a platinum-based, palladium-based or other precious metal catalyst.

[0084] In one embodiment, in step (3), a portion of the catalytic oxidation flue gas is cooled and cooled by its heat storage body and then output through its cooling flue gas outlet, which means that a portion of the catalytic oxidation flue gas will be used to heat the cold side heat storage body in the exhaust gas heat storage catalytic oxidation unit 6 to store heat and maintain stable operation of the catalytic oxidation device, and then the flue gas itself is cooled and cooled, and the resulting cooled catalytic oxidation flue gas is output through its cooling flue gas outlet.

[0085] In one embodiment, the method further comprises:

[0086] In step (3), part of the thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 is sent to the exhaust gas thermal storage catalytic oxidation unit 6 through the first thermal oxidation flue gas pipeline 51;

[0087] Preferably, in step (3), part of the thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 is sent from the thermal storage thermal oxidation chamber through the first thermal oxidation flue gas pipe 51 into the thermal storage catalytic oxidation chamber in the exhaust gas thermal storage catalytic oxidation unit 6.

[0088] Those skilled in the art understand that in step (3), the catalytic oxidation reaction in the exhaust gas thermal storage catalytic oxidation unit 6 will continuously increase the temperature in the thermal storage catalytic oxidation chamber under the continuous action of part of the thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4, thereby improving the gas oxidation efficiency.

[0089] In one embodiment, the method further comprises:

[0090] In step (4), part of the thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4 is sent into the oxidation waste heat comprehensive utilization unit through the second thermal oxidation flue gas pipeline 52.

[0091] Those skilled in the art understand that the demand for heat load of the RTO system varies according to the season. The amount of thermal oxidation flue gas fed into the exhaust gas thermal storage catalytic oxidation unit 6 in step (3) can be adjusted to increase the amount of heat entering the exhaust gas thermal storage catalytic oxidation unit 6, thereby increasing the exhaust gas processing capacity of the exhaust gas thermal storage catalytic oxidation unit 6 and realizing the utilization of a controllable amount of exhaust gas until all the exhaust gas is utilized.

[0092] In one embodiment, in step (4), when the thermal energy is comprehensively utilized, the thermal oxidation flue gas and the catalytic oxidation flue gas are first introduced into the waste heat boiler 71 in the oxidation waste heat comprehensive utilization unit to produce steam, and then the heat using unit 72 utilizes the steam from the waste heat boiler 71, for example, the steam from the waste heat boiler 71 is used to heat the return air shaft of the mining area and heat the factory area through a heat exchange station or directly supply steam. In summer, according to economic needs, the steam can be used for self-use in the power plant through a steam turbine and a generator, or for cooling the factory area through a heat pump system;

[0093] When the temperature in the exhaust gas thermal storage catalytic oxidation unit 6 gradually increases, the temperature in the exhaust gas thermal storage catalytic oxidation unit 6 can be reduced by increasing the exhaust gas processing capacity, making full use of the waste heat of the low-concentration gas thermal storage thermal oxidation unit 4, or the catalytic oxidation flue gas generated in the exhaust gas thermal storage catalytic oxidation unit 6 can be drawn out and sent to the oxidation waste heat comprehensive utilization unit for comprehensive heat utilization to reduce the temperature in the exhaust gas thermal storage catalytic oxidation unit 6; wherein,

[0094] In summer, when the demand for heating in coal mines is low, the comprehensive economic efficiency of power generation is not high, and the carbon emission reduction benefits (CCER carbon market) are large, all the thermal oxidation flue gas generated by the low-concentration gas thermal storage thermal oxidation unit 4 can be sent to the exhaust gas thermal storage catalytic oxidation unit 6 to further increase the exhaust gas processing capacity, achieve total exhaust gas methane emission reduction, and increase carbon emission reduction benefits;

[0095] In winter, the demand for heating in coal mines is relatively high, and the excess part of the thermal oxidation flue gas generated by the low-concentration gas heat storage thermal oxidation unit 4 can be mainly sent to the oxidation waste heat comprehensive utilization unit for comprehensive heat utilization.

[0096] In one embodiment, the method further comprises:

[0097] In step (3), the discharge valve 511 is used to control the flow of the material in the first thermal oxidation flue gas duct 51, such as cutoff, flow, flow rate, etc.; and / or

[0098] In step (4), the discharge valve 521 is used to control the flow of materials in the second thermal oxidation flue gas duct 52, such as cutoff, flow, flow rate, etc.

[0099] In one embodiment, the method further comprises:

[0100] The fan 81 is used to send the cooled thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 and the cooled catalytic oxidation flue gas from the exhaust gas thermal storage catalytic oxidation unit 6 into the chimney 82 and then discharge them.

[0101] Preferably, the method further comprises:

[0102] In step (5), the mixed flue 83 is used to receive and buffer the cooled thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 and the cooled catalytic oxidation flue gas from the exhaust gas thermal storage catalytic oxidation unit 6 to supply the fan 81.

[0103] In one embodiment, the method further comprises:

[0104] In step (4), the thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4 and the catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit 6 are introduced into the waste heat boiler 71 and the heat energy therein is used to produce steam; the steam from the waste heat boiler 71 is sent to the heat utilization unit 72 for utilization, thereby realizing the cascade utilization of energy.

[0105] In one embodiment, the method further comprises:

[0106] The flue gas from the waste heat boiler 71 is sent to the discharge unit through the flue gas conveying pipe 711 for discharge.

[0107] When the system for coal mine gas carbon reduction and utilization of the present invention is in operation:

[0108] After being preheated (e.g., by natural gas), the low-concentration extracted gas heat storage thermal oxidation unit 4 introduces the mixed gas and heats it up under the action of the heat storage body therein, undergoing a thermal oxidation reaction to generate high-temperature thermal oxidation flue gas. Part of the thermal oxidation flue gas is used to heat the internal cold-side heat storage body to maintain the stable operation of the thermal oxidation device, and then outputs cooled thermal oxidation flue gas. Part of the thermal oxidation flue gas is directly fed into the oxidation waste heat comprehensive utilization unit and the exhaust gas heat storage catalytic oxidation unit 6.

[0109] After preheating the exhaust gas heat storage catalytic oxidation unit 6 with part of the thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4, part of the exhaust gas from the exhaust gas collection and transportation distribution unit 2 is introduced to heat and increase the temperature under the action of the heat storage body therein, and to carry out catalytic oxidation reaction of methane to destroy the gas, reduce methane emissions, and produce high-temperature catalytic oxidation flue gas; part of the catalytic oxidation flue gas is used to heat the heat storage body on the cold side thereof to maintain the stable operation of the catalytic oxidation device and then output the cooled catalytic oxidation flue gas, and part of the catalytic oxidation flue gas is directly sent to the comprehensive utilization unit of the oxidation waste heat.

[0110] The system and method for coal mine gas carbon reduction utilization of the present invention realizes the full economic carbon emission reduction of low-concentration extracted gas and exhaust gas from coal mines and turns waste into treasure through the combined technology of thermal oxidation and catalytic oxidation, obtains methane energy benefits, overcomes the shortcomings of a single technology itself, and gives play to the combined advantages; fully utilizes the characteristics of thermal oxidation in converting high-quality thermal energy of gas and low construction cost, combines waste heat boilers and power generation and heating systems, and generates electricity and supplies heat and cooling to the high-temperature heat source - thermal oxidation flue gas and catalytic oxidation flue gas, thereby achieving gas carbon emission reduction and obtaining energy supply income; overcomes the shortcomings of large heat energy loss in the thermal storage thermal oxidation unit of low-concentration extracted gas, and sends the heat loss into the exhaust gas thermal storage catalytic oxidation unit through the first thermal oxidation flue gas pipeline 51 and the discharge valve 511 thereon to be utilized, thereby increasing the operating temperature of the catalytic oxidation reaction in the exhaust gas thermal storage catalytic oxidation unit and improving the exhaust gas The conversion efficiency of gas; and when the heating load is small and the power generation efficiency is low in the non-heating season, the heat energy of the low-concentration extracted gas heat storage thermal oxidation unit is mainly sent to the exhaust gas heat storage catalytic oxidation unit to be utilized, further improving the exhaust gas catalytic oxidation processing capacity, increasing the carbon emission reduction, and increasing the carbon emission reduction benefits through energy cascade utilization; overcoming the shortcomings of low gas concentration, large fluctuation, and difficulty in maintaining self-heating balance in a single exhaust gas catalytic oxidation system, by utilizing the heat energy of the low-concentration extracted gas heat storage thermal oxidation unit, saving additional energy input, reducing operating costs, increasing operating temperature, improving methane oxidation efficiency, increasing exhaust gas carbon emission reduction, and obtaining carbon emission reduction effects and carbon emission reduction benefits; the system and method for coal mine gas carbon reduction utilization of the present invention, the thermal oxidation technology and the catalytic oxidation technology cooperate with each other to make the system operation more flexible, practical, and economical, with good environmental and economic benefits.

[0111] The present invention is further illustrated below by means of specific examples.

[0112] In the determination / calculation of relevant parameters in the following examples and comparative examples of the present invention:

[0113] Reduction of carbon dioxide equivalent emissions, calculated as 25 tons of carbon dioxide equivalent for every ton of methane destroyed;

[0114] The selling price of carbon dioxide emission reduction equivalent CCER carbon trading is calculated at 55 yuan / t;

[0115] The selling price of steam is calculated at RMB 155 per ton;

[0116] Annual operating hours are calculated as 8760h;

[0117] The operating hours of the device during the heating season each year are calculated as 3600h;

[0118] The operating hours of non-heating equipment each year are calculated as 5160 hours;

[0119] The methane oxidation efficiency in the ventilation gas thermal storage catalytic oxidation unit is designed to be 90%;

[0120] The methane oxidation efficiency in the thermal storage thermal oxidation unit for low-concentration gas extraction is designed to be 99.6%;

[0121] The waste heat boiler is designed to have a boiler efficiency of 90%.

[0122] Example 1 (S1)

[0123] Use Figure 1 The system shown is used to reduce carbon emissions from coal mine gas. The gas directly emitted on site includes low-concentration extraction gas and ventilation gas. The concentration of low-concentration extraction gas is 6v%, and the emission volume is 40,000 Nm 3 / h; the concentration of ventilation gas is 0.1v%, and the emission volume is 2.5 million Nm 3 / h;

[0124] Methods include:

[0125] (1) All low-concentration gas (40,000 Nm3) from the low-concentration gas delivery unit 1 is transported to the 3 / h) and part of the ventilation gas from the ventilation gas collection and transportation distribution unit 2 (175,000 Nm 3 / h) are respectively sent into the gas blending unit 3 for blending, with an output concentration of 1.2v% and a flow rate of 215,000 Nm 3 / h of mixed gas;

[0126] (2) The blended gas from the gas blending unit 3 is sent into the low-concentration extracted gas thermal storage thermal oxidation unit 4 that has been preheated to 950°C for thermal oxidation reaction to release heat, generating 950°C thermal oxidation flue gas, of which 74.6% of the thermal oxidation flue gas enters the thermal storage chamber of the low-concentration extracted gas thermal storage thermal oxidation unit 4 to heat the thermal storage body therein to store heat for maintaining self-heating balance, and is cooled and then output through its cooling flue gas outlet, and the remaining 25.4% of the thermal oxidation flue gas is directly output through its flue gas outlet;

[0127] (3) During the heating season, due to the high demand for heat, 100% of the thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 is sent to the oxidation waste heat comprehensive utilization unit, heated by the waste heat boiler 71, and steam is generated to meet the on-site heating demand, generating 102,000 tons of hot steam per heating season;

[0128] During the heating season, the low-concentration gas thermal storage thermal oxidation unit 4 (RTO) treated 175,000 m3 of ventilation gas. 3 / h, reducing methane emissions from ventilation gas by nearly 0.125t / h, reducing methane emissions from extraction gas by nearly 1.705t / h, and reducing CO2 equivalent emissions by a total of nearly 45.8t / h (the total CO2 equivalent reduction during the heating season is approximately 165,000 tons);

[0129] During the heating season, the ventilation gas thermal storage catalytic oxidation unit 6 (RCO) processed 00,000 m 3 / h, reducing CO2 equivalent by nearly 0t / h (the total CO2 equivalent reduction during the heating season is about 00,000 tons).

[0130] (4) During the non-heating season, when there is no demand for heating or other energy, or when the low-concentration extracted gas thermal storage thermal oxidation unit 4 is overheating, the discharge valve 511 is opened and the discharge valve 521 is closed, and the thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 (all the thermal oxidation flue gas directly output through its flue gas outlet) is sent to the exhaust gas thermal storage catalytic oxidation unit 6 to preheat its thermal storage catalytic oxidation chamber to 600°C;

[0131] Then, part of the exhaust gas (2.255 million Nm3) from the exhaust gas collection and transportation distribution unit 2 is introduced into the exhaust gas thermal storage catalytic oxidation unit 6. 3 / h), in which the catalytic oxidation reaction of methane is carried out to release heat, generating catalytic oxidation flue gas at 650°C, part of which is cooled by the heat storage body and then output through its cooling flue gas outlet, and the rest is directly output through its flue gas outlet; wherein,

[0132] Under the condition that the heat of the thermal oxidation flue gas discharged from the discharge valve 511 is supplemented, the ventilation gas is stably catalytically oxidized;

[0133] During the non-heating season, the low-concentration gas thermal storage thermal oxidation unit 4 (RTO) treats 175,000 m3 of ventilation gas. 3 / h, reducing methane emissions from ventilation gas by nearly 0.125t / h, reducing methane emissions from extraction gas by nearly 1.705t / h, and reducing CO2 equivalent emissions by a total of nearly 45.8t / h (the total CO2 equivalent reduction during the non-heating season is approximately 236,000 tons);

[0134] During the non-heating season, the ventilation gas thermal storage catalytic oxidation unit 6 (RCO) processed 2.255 million m3 of ventilation gas. 3 / h, reducing methane emissions from ventilation gas by nearly 1.61t / h and CO2 equivalent emissions by nearly 40.3t / h (the total CO2 equivalent emission reduction during the non-heating season is approximately 208,000 tons);

[0135] (5) The cooled thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4, the cooled catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit 6, and the cooled flue gas from the oxidation waste heat comprehensive utilization unit are respectively sent to the emission unit for emission.

[0136] In Example 1, the total methane emission reduction of the on-site direct gas emissions is about 24,400 tons / year, and the total CO2 emission reduction equivalent is about 608,900 tons / h, which can increase the carbon emission reduction income by 33.492 million yuan / year and the energy supply income by 15.806 million yuan / year, with a total income of 49.298 million yuan / year.

[0137] Example 2 (S2)

[0138] Carbon reduction and utilization of coal mine gas was carried out according to the method of Example 1. Compared with Example 1, the only differences are as follows:

[0139] According to the on-site energy supply requirements:

[0140] In step (3), during the heating season, 80% of the thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 is sent to the waste heat boiler 71 in the oxidation waste heat comprehensive utilization unit for heating, and 20% is sent to the exhaust gas thermal storage catalytic oxidation unit 6 (RCO); wherein,

[0141] During the heating season, 102,000 tons of hot steam are generated per heating season;

[0142] During the heating season, the low-concentration gas thermal storage thermal oxidation unit 4 (RTO) treated 175,000 m3 of ventilation gas. 3 / h, reducing methane emissions from ventilation gas by nearly 0.125t / h, reducing methane emissions from extraction gas by nearly 1.705t / h, and reducing CO2 equivalent emissions by a total of nearly 45.8t / h (the total CO2 equivalent reduction during the heating season is approximately 165,000 tons);

[0143] During the heating season, the ventilation gas thermal storage catalytic oxidation unit 6 (RCO) processed 451,000 m3 of ventilation gas. 3 / h, reducing methane emissions from ventilation gas by nearly 0.32t / h and CO2 equivalent emissions by nearly 8.1t / h (the total CO2 equivalent reduction during the heating season is approximately 29,000 tons)

[0144] In step (4), in the non-heating season, 20% of the thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit 4 is sent to the waste heat boiler 71 in the oxidation waste heat comprehensive utilization unit for heating, and 80% is sent to the exhaust gas thermal storage catalytic oxidation unit 6 (RCO); and the amount of exhaust gas from the exhaust gas collection and transportation distribution unit 2 introduced into the exhaust gas thermal storage catalytic oxidation unit 6 is 1.804 million Nm3 / h; among them,

[0145] During the non-heating season, the low-concentration gas thermal storage thermal oxidation unit 4 (RTO) treats 175,000 m3 of ventilation gas. 3 / h, reducing methane emissions from ventilation gas by nearly 0.125t / h, reducing methane emissions from extraction gas by nearly 1.705t / h, and reducing CO2 equivalents by a total of nearly 45.8t / h (the total CO2 equivalent reduction during the non-heating season is approximately 236,000 tons);

[0146] During the non-heating season, the ventilation gas thermal storage catalytic oxidation unit 6 (RCO) processed 1.804 million m3 of ventilation gas. 3 / h, reducing methane emissions from ventilation gas by nearly 1.29t / h and CO2 equivalent emissions by nearly 32.2t / h (the total CO2 equivalent emission reduction during the non-heating season is approximately 166,000 tons).

[0147] In Example 2, the total methane emission reduction of the on-site direct gas emissions is about 23,900 tons / year, and the total CO2 emission reduction equivalent is about 596,400 tons / h, which can increase the carbon emission reduction income by 32.801 million yuan / year and the energy supply income by 17.175 million yuan / year, with a total income of 49.976 million yuan / year.

[0148] Comparative Example 1 (D1)

[0149] Only use the Figure 1 The low-concentration extracted gas thermal storage thermal oxidation unit 4 (RTO system) in the system shown is used to reduce carbon utilization of coal mine gas; using the same parameters; compared with Example 1, it has the following differences:

[0150] In step (3), during the heating season, 100% of the thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4 is sent to the waste heat boiler 71 in the oxidation waste heat comprehensive utilization unit for heating; wherein,

[0151] During the heating season, 102,000 tons of hot steam are generated per heating season;

[0152] During the heating season, the low-concentration gas thermal storage thermal oxidation unit 4 (RTO) treated 175,000 m3 of ventilation gas. 3 / h, reducing methane emissions from ventilation gas by nearly 0.125t / h, reducing methane emissions from extraction gas by nearly 1.705t / h, and reducing CO2 equivalent emissions by a total of nearly 45.8t / h (the total CO2 equivalent reduction during the heating season is approximately 165,000 tons);

[0153] In step (4), in the non-heating season, there is no other energy demand such as heating, and there is no RCO system, so the RTO system does not operate;

[0154] In step (5), the cooled thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit 4 and / or the cooled flue gas from the oxidation waste heat comprehensive utilization unit are respectively sent to the emission unit for emission.

[0155] In Comparative Example 1, the total methane emission reduction in the on-site direct gas emissions is about 6,600 t / year, and the total CO2 emission reduction equivalent is about 165,000 t / h, which can increase the carbon emission reduction income by 9.075 million yuan / year and the energy supply income by 15.806 million yuan / year, with a total income of 24.885 million yuan / year.

[0156] For a standalone RTO system, it can operate at full load during the heating season, but during the non-heating season, its ability to absorb the excess heat generated is limited. The current economic benefits of steam turbine power generation are poor and the operation is difficult, especially for small-scale gas volumes. It is chosen not to build a supporting steam generator set and only operate it during the heating season, not during the non-heating season.

[0157] For the RCO system or RTO system operated alone, especially when the gas concentration is low (<0.2%), the RCO system needs to introduce an additional heat source and the operating cost is high. It is difficult to control the exhaust gas by operating the RCO system alone and it is not easy to promote.

[0158] The relevant parameters of Example 1-2 (S1-2) and Comparative Example 1 (D1) were measured and calculated, and the results are shown in Table 1.

[0159] Table 1 Results of Example 1 (S1-2) and Comparative Example 1 (D1)

[0160]

[0161] According to Examples 1-2, Comparative Example 1 and Table 1, it can be seen that:

[0162] Compared with Comparative Example 1, the annual CO2 emission reduction equivalent in Examples 1-2 of the present invention is increased to about 4 times, and the annual income is increased to about 2 times or even more, with significant carbon emission reduction effect, good environmental effect and high economic benefits.

Claims

1. A system for reducing carbon emissions from coal mine gas, characterized in that: The system comprises a low-concentration extracted gas transportation unit (1), a ventilation gas collection and transportation distribution unit (2), a gas blending unit (3), a low-concentration extracted gas heat storage thermal oxidation unit (4), a ventilation gas heat storage catalytic oxidation unit (6), an oxidation waste heat comprehensive utilization unit and an emission unit, which are connected by pipelines; wherein, The inlet of the gas blending unit (3) is connected to the outlet of the low-concentration extracted gas delivery unit (1) and the exhaust gas collection and delivery distribution unit (2), respectively, for respectively introducing low-concentration extracted gas and exhaust gas and blending them to obtain blended gas; The low-concentration extracted gas heat storage thermal oxidation unit (4) comprises a mixed gas inlet, a heat storage body, a hot flue gas outlet and a cooling flue gas outlet, and the mixed gas inlet is connected to the outlet of the gas mixing unit (3) and is used to perform a thermal oxidation reaction on the mixed gas from the gas mixing unit (3) to obtain thermally oxidized flue gas, a portion of which is cooled by the heat storage body and then output through the cooling flue gas outlet, and the remaining portion is directly output through the hot flue gas outlet; The exhaust gas thermal storage catalytic oxidation unit (6) includes an exhaust gas inlet, a heat storage body, a methane oxidation catalyst, a flue gas inlet, a hot flue gas outlet and a cooling flue gas outlet, and its exhaust gas inlet is connected to the exhaust gas collection and transportation distribution unit (2) for feeding exhaust gas, and its flue gas inlet is connected to the hot flue gas outlet of the low-concentration extracted gas thermal storage thermal oxidation unit (4) for feeding the hot oxidized flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit (4) to perform auxiliary heating on the exhaust gas fed into the exhaust gas thermal storage catalytic oxidation unit (6) for catalytic oxidation reaction, thereby obtaining catalytically oxidized flue gas, a part of which is cooled by the heat storage body and then outputted through the cooling flue gas outlet, and the rest is directly outputted through the hot flue gas outlet; The inlet of the oxidation waste heat comprehensive utilization unit is respectively connected to the hot flue gas outlets of the low-concentration extracted gas heat storage thermal oxidation unit (4) and the exhaust gas heat storage catalytic oxidation unit (6), and is used to cool down part of the hot oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit (4) and the catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit (6) after utilization, and output the cooled flue gas; The inlet of the discharge unit is respectively connected to the cooling flue gas outlets of the low-concentration extracted gas heat storage thermal oxidation unit (4) and the exhaust gas heat storage catalytic oxidation unit (6) and the flue gas outlet of the oxidation waste heat comprehensive utilization unit, and is used to discharge the cooling thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit (4), the cooling catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit (6) and the cooling flue gas from the oxidation waste heat comprehensive utilization unit.

2. The system according to claim 1, wherein: The low-concentration extracted gas heat storage thermal oxidation unit (4) is provided with a heat storage thermal oxidation chamber, and the exhaust gas heat storage catalytic oxidation unit (6) is provided with a heat storage catalytic oxidation chamber. Both ends of a first thermal oxidation flue gas pipeline (51) from the low-concentration extracted gas heat storage thermal oxidation unit (4) to the exhaust gas heat storage catalytic oxidation unit (6) are connected to the heat storage thermal oxidation chamber and the heat storage catalytic oxidation chamber respectively.

3. The system according to claim 2, characterized in that A discharge valve (511) is provided on the first thermal oxidation flue gas pipeline (51) from the low-concentration extracted gas heat storage thermal oxidation unit (4) to the exhaust gas heat storage catalytic oxidation unit (6) for controlling the flow of materials in the first thermal oxidation flue gas pipeline (51).

4. The system according to claim 1, wherein: A discharge valve (521) is provided on the second thermal oxidation flue gas pipeline (52) from the low-concentration extracted gas heat storage thermal oxidation unit (4) to the oxidation waste heat comprehensive utilization unit for controlling the flow of materials in the second thermal oxidation flue gas pipeline (52).

5. The system according to any one of claims 1 to 4, characterized in that The discharge unit includes a fan (81) and a chimney (82) connected in sequence, and is respectively connected to the flue gas outlets of the low-concentration extracted gas heat storage thermal oxidation unit (4) and the exhaust gas heat storage catalytic oxidation unit (6) and the flue gas outlet of the oxidation waste heat comprehensive utilization unit through the inlet of the fan (81), so as to use the fan (81) to send the cooled catalytic oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit (4), the cooled catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit (6) and the cooled flue gas from the oxidation waste heat comprehensive utilization unit into the chimney (82) for discharge.

6. The system according to claim 5, characterized in that The discharge unit further includes a mixing flue (83), which is arranged at the inlet end of the fan (81) and is used to receive and buffer the cooled thermal oxidation flue gas from the low-concentration extracted gas thermal storage thermal oxidation unit (4) and the cooled catalytic oxidation flue gas from the exhaust gas thermal storage catalytic oxidation unit (6) to supply the fan (81).

7. The system according to any one of claims 1 to 4 and 6, characterized in that The oxidation waste heat comprehensive utilization unit includes a waste heat boiler (71) and a heat utilization unit (72) connected by pipelines; and the inlet of the waste heat boiler (71) is respectively connected to the flue gas outlets of the low-concentration extracted gas heat storage thermal oxidation unit (4) and the exhaust gas heat storage catalytic oxidation unit (6), for introducing the thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit (4) and the catalytic oxidation hot flue gas from the exhaust gas heat storage catalytic oxidation unit (6) and utilizing the heat energy therein to produce steam; the heat utilization unit (72) is connected to the steam outlet of the waste heat boiler (71) for utilizing the steam from the waste heat boiler (71).

8. The system according to claim 7, characterized in that A flue gas conveying pipe (711) is provided from the flue gas outlet of the waste heat boiler (71) to the inlet of the discharge unit, for conveying the flue gas from the waste heat boiler (71) to the discharge unit for discharge.

9. The system according to claim 7, wherein: In the oxidation waste heat comprehensive utilization unit, the heat using unit (72) includes a heat supply unit and / or a power generation unit, the heat supply unit includes any one or more combinations of mine heating, cooling, and industrial steam, and the power generation unit includes a steam turbine and a generator connected in sequence.

10. A method for reducing carbon in coal mine gas using the system according to any one of claims 1 to 9, characterized in that: The method comprises: (1) The low-concentration extracted gas from the low-concentration extracted gas delivery unit (1) and the exhaust gas from the exhaust gas collection and delivery distribution unit (2) are respectively delivered into the gas blending unit (3) for blending to obtain blended gas; (2) The mixed gas from the gas mixing unit (3) is sent into the low-concentration extracted gas heat storage thermal oxidation unit (4) for thermal oxidation reaction to obtain thermal oxidation flue gas, a portion of which is cooled by the heat storage body and output through the cooling flue gas outlet, and the remaining portion is directly output through the hot flue gas outlet; (3) sending part of the thermally oxidized flue gas from the low-concentration extracted gas heat storage thermal oxidation unit (4) and part of the exhaust gas from the exhaust gas collection and transportation distribution unit (2) into the exhaust gas heat storage catalytic oxidation unit (6), using part of the thermally oxidized flue gas from the low-concentration extracted gas heat storage thermal oxidation unit (4) to assist part of the exhaust gas from the exhaust gas collection and transportation distribution unit (2) in a catalytic oxidation reaction, thereby obtaining catalytically oxidized flue gas, part of which is cooled by its heat storage body and then outputted through its cooling flue gas outlet, and the rest is directly outputted through its hot flue gas outlet; (4) sending part of the thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit (4) and / or the catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit (6) into the oxidation waste heat comprehensive utilization unit for utilization; (5) The cooled thermal oxidation flue gas from the low-concentration extracted gas heat storage thermal oxidation unit (4) and / or the cooled catalytic oxidation flue gas from the exhaust gas heat storage catalytic oxidation unit (6) are respectively sent to the emission unit for emission.

11. The method according to claim 10, characterized in that A discharge valve (511) is provided on the first thermal oxidation flue gas pipeline (51) from the low-concentration extracted gas heat storage thermal oxidation unit (4) to the exhaust gas heat storage catalytic oxidation unit (6); A discharge valve (521) is provided on a second thermal oxidation flue gas pipeline (52) from the low-concentration extracted gas heat storage thermal oxidation unit (4) to the oxidation waste heat comprehensive utilization unit; The method further comprises: In step (3), the discharge valve (511) is used to control the flow of materials in the first thermal oxidation flue gas duct (51); and / or In step (4), the discharge valve (521) is used to control the flow of materials in the second thermal oxidation flue gas duct (52).

12. The method according to claim 10 or 11, characterized in that The oxidation waste heat comprehensive utilization unit comprises a waste heat boiler (71); a flue gas conveying pipe (711) is provided from the flue gas outlet of the waste heat boiler (71) to the inlet of the discharge unit; The method further comprises: The flue gas from the waste heat boiler (71) is sent to the discharge unit through the flue gas conveying pipeline (711) for discharge.

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