A system and method for thermal storage and oxidation utilization of coal mine exhaust air mixed with coal powder

Abstract

The present invention discloses a system and method for thermal storage oxidation utilization of coal mine ventilation mixed with coal powder, which relates to the field of extremely low concentration gas oxidation utilization and coal mine energy conservation and emission reduction technology. The system includes ventilation gas gas conveying device, coal powder conveying device, thermal storage oxidation device and energy utilization device. The present invention stabilizes the thermal storage oxidation operation by adding high-quality coal powder, reduces the minimum methane concentration and oxidation temperature that can sustain self-operation, and greatly improves the utilization efficiency of ventilation gas; at the same time, the present invention solves the problem that ventilation and low-concentration gas in coal mines cannot be directly utilized, converts ventilation gas into thermal energy and uses it for power generation and heating, which can greatly improve the utilization efficiency of ventilation gas, effectively solve the contradiction of tight power supply in mining areas and the environmental protection pressure of carbon peak and carbon neutrality, and can effectively reduce the cost of heating and energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of extremely low concentration gas oxidation utilization and coal mine energy conservation and emission reduction, and in particular to a system and method for thermal storage oxidation utilization of coal mine exhaust air mixed with coal powder. Background Art

[0002] The global warming phenomenon caused by large carbon dioxide emissions is becoming increasingly serious, which has a huge impact on the sustainable development of the world economy and society. With the reduction of fossil fuel reserves and severe ecological and environmental problems, the efficient use of clean energy has become an inevitable trend in the development of a low-carbon economy.

[0003] Methane, as a clean energy source associated with coal mining, has attracted much attention due to its large emissions, high calorific value, and low content of carbon dioxide and nitrogen oxides in combustion exhaust gas. At the same time, methane is considered to be the second largest greenhouse gas after carbon dioxide. About 25 million tons of CH4 are emitted from coal mining each year worldwide, of which 70% of methane comes from mine return air flow with a concentration of less than 1% (also known as "lack of air methane"). Lack of air methane is difficult to be utilized by conventional combustion technology due to its low methane content and large flow rate variation. Most of the unused lack of air methane is directly discharged into the atmosphere, which not only causes a huge waste of clean energy, but also continuously aggravates the evolution of the greenhouse effect and causes serious damage to the ecological environment. Obviously, the fundamental reason for the large amount of methane emissions is the low utilization rate of lack of air methane. Therefore, improving the utilization rate of lack of air methane and thus improving the environment has an important impact.

[0004] The main component of ventilation gas is methane, whose lower calorific value under standard conditions is 35.88MJ / m 3 When the reaction reaches a certain temperature, CH4 and O2 undergo oxidation reaction to generate carbon dioxide and water, and release a large amount of heat. It is a clean and efficient green energy. Assuming that the average concentration of methane in the mine ventilation gas is 0.5% and the average flow rate is 80,000 m 3 / h. If this part of methane is fully utilized, the annual treatment of mine ventilation gas can reach 700.8 million m 3 , the annual heat recovery is 125820GJ, the electricity generated is 34950MW, and the greenhouse gas emission reduction can reach 52000t CO2 equivalent. Therefore, the research on the utilization technology of coal mine ventilation is of great practical significance for the development of efficient and clean energy, ensuring the safe production of coal mines, reducing greenhouse gas emissions, and achieving sustainable development of energy.

[0005] At present, the conversion and utilization of exhaust gas are mainly divided into auxiliary fuel utilization technology and main fuel utilization technology. Auxiliary fuel utilization technology is to use exhaust gas to replace air for mixed combustion, which is mainly used in gas turbines, internal combustion engines, coal-fired boilers, fluidized bed furnaces, etc. Although auxiliary fuel utilization technology seems to be the simplest and most economical utilization method, it is difficult to implement because the amount of exhaust gas it treats is limited and it needs to be built close to the ventilation wellhead, and it is difficult to achieve the ideal emission reduction effect. The main fuel utilization technology uses methane in the exhaust gas of coal mines as the main fuel, which is divided into thermal storage oxidation technology and catalytic oxidation technology. The only difference between the two is whether a catalyst is used; although both technologies can improve the utilization rate of gas and thus achieve greenhouse gas emission reduction; however, the high temperature in catalytic oxidation may cause catalyst poisoning and deactivation, and the cost of expensive catalysts is high. Therefore, thermal storage oxidation technology is widely used in industry with good economic applicability, but due to the low methane concentration, the radiation heat transfer of its flame is small and there is heat dissipation loss in the combustion system, so it cannot maintain the stable operation of the oxidation device for a long time. Usually, the extracted high-concentration gas (CH4%>30%) is mixed with the exhaust gas for oxidation reaction, and the heat generated is comprehensively utilized. However, the cost of utilizing high-concentration gas is relatively high, and the utilization method after oxidation is generally mainly low-grade thermal energy utilization, and the utilization efficiency is low. Summary of the invention

[0006] The purpose of the present invention is to provide a system and method for thermal storage and oxidation utilization of coal mine exhaust air mixed with coal powder, so as to improve the utilization rate of exhaust air gas at low cost, so as to reduce the energy waste and environmental pollution caused by exhaust air gas emission, and achieve the goal of sustainable development of energy conservation and emission reduction.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A coal mine ventilation air mixed with coal powder heat storage oxidation utilization system, comprising a ventilation air gas conveying device, a coal powder conveying device, a heat storage oxidation device and an energy utilization device;

[0009] The air-lack gas conveying device is connected with the upper input end of the thermal storage oxidation device through the gas conveying pipeline and the first connecting pipe in sequence; the upper output end of the thermal storage oxidation device is connected with the energy utilization device through the second connecting pipe and the heat conducting pipe in sequence; the air-lack gas conveying device is connected with the lower input end of the thermal storage oxidation device through the gas conveying pipeline and the third connecting pipe in sequence; the lower output end of the thermal storage oxidation device is connected with the energy utilization device through the fourth connecting pipe and the heat conducting pipe in sequence; the pulverized coal conveying device is connected with the upper input end of the thermal storage oxidation device through the fifth connecting pipe; wherein a first solenoid valve is installed on the first connecting pipe; a second solenoid valve is installed on the second connecting pipe; a third solenoid valve is installed on the third connecting pipe; and a fourth solenoid valve is installed on the fourth connecting pipe;

[0010] The air-deficient methane gas conveying device is used to convey air-deficient methane gas; the pulverized coal conveying device is used to convey target pulverized coal; wherein the mass of the target pulverized coal per unit time is determined according to the proportion of heat generated by the air-deficient methane gas per unit time;

[0011] The thermal storage oxidation device is used to generate flue gas according to the reaction between the exhaust gas and the target pulverized coal; the thermal energy of the flue gas includes a first part of thermal energy, a second part of thermal energy and a third part of thermal energy; the first part of thermal energy is used to maintain the operation of the thermal storage oxidation device; the energy utilization device is used to convert the second part of thermal energy into electrical energy and perform heat exchange operation on the third part of thermal energy;

[0012] During operation, the first solenoid valve and the fourth solenoid valve are controlled to be opened, and the second solenoid valve and the third solenoid valve are controlled to be closed, so that the air-deficient methane gas and the target pulverized coal enter the thermal storage oxidation device through the upper input end, and the flue gas generated by the thermal storage oxidation device enters the energy utilization device through the lower output end; the first solenoid valve and the fourth solenoid valve are controlled to be closed, and the second solenoid valve and the third solenoid valve are controlled to be opened, so that the air-deficient methane gas enters the thermal storage oxidation device through the lower input end, and the target pulverized coal enters the thermal storage oxidation device through the upper input end, and the flue gas generated by the thermal storage oxidation device enters the energy utilization device through the upper output end. The cycle operation is carried out so that the air-deficient methane gas is mixed with the target pulverized coal and burned in the thermal storage oxidation device, thereby recovering heat.

[0013] Optionally, the exhaust gas gas delivery device includes a methane gas tank, an air compressor and a gas premixing chamber;

[0014] The methane gas tank is connected to the gas premixing chamber through a sixth connecting pipe; the air compressor is connected to the gas premixing chamber through a seventh connecting pipe; the output end of the gas premixing chamber is the output end of the exhaust gas gas delivery device;

[0015] According to the gas delivery direction, the sixth connecting pipe is sequentially installed with a second pressure reducing valve, a second valve, a mass flow meter and a fourth valve, and the seventh connecting pipe is sequentially installed with a first pressure reducing valve, a first valve, a glass rotor flow meter and a third valve.

[0016] Optionally, the pulverized coal conveying device comprises a pulverized coal bin, a continuous pulverized coal supply assembly and a blower;

[0017] The continuous powder supply component is arranged on the output end of the coal powder bin; the continuous powder supply component is used to control the output amount of coal powder in the coal powder bin; the output end of the coal powder bin is connected to the first input end of the fifth connecting pipe, the blower is connected to the second input end of the fifth connecting pipe, and the output end of the fifth connecting pipe is connected to the upper input end of the thermal storage oxidation device.

[0018] Optionally, the thermal storage oxidation device includes a combustion chamber, an insulating layer for wrapping the combustion chamber, thermal storage ceramics installed in the middle area of ​​the inner cavity of the combustion chamber, and a pulverized coal combustion nozzle arranged in the top area of ​​the inner cavity of the combustion chamber; the pulverized coal combustion nozzle is connected to the upper input end.

[0019] Optionally, it further comprises a temperature monitoring device; the temperature monitoring device comprises a thermocouple, a temperature data acquisition module connected to one end of the thermocouple, and a computer for acquiring temperature information collected by the temperature data acquisition module;

[0020] There are multiple thermocouples, and the other ends of the multiple thermocouples are evenly distributed on the thermal storage ceramic according to vertical distances.

[0021] Optionally, the energy utilization device includes a heat exchange module, a steam turbine and a heat exchanger;

[0022] The input end of the heat exchange module is in communication with the first output end of the heat conducting pipe, and the heat exchange module is used to obtain the heat of the flue gas transmitted by the heat conducting pipe to obtain superheated steam and low-temperature steam;

[0023] The first output end of the heat exchange module is connected to the steam turbine, and the heat exchange module is used to transmit the superheated steam to the steam turbine; the steam turbine is used to generate electricity according to the superheated steam;

[0024] The second output end of the heat exchange module is connected to the heat exchanger; the heat exchange module is used to transmit the low-temperature steam to the heat exchanger; the heat exchanger is used to perform heat exchange based on the low-temperature steam to generate hot water.

[0025] Optionally, a gas chromatograph is also included;

[0026] The first input end of the gas chromatograph is connected to the second output end of the heat conducting pipe through an eighth connecting pipe; the second input end of the gas chromatograph is connected to the gas delivery pipeline through a ninth connecting pipe;

[0027] The gas chromatograph is used to analyze the concentration and composition of the flue gas, and to analyze the concentration and composition of the ventilation methane gas.

[0028] A method for thermal storage and oxidation utilization of coal mine exhaust air mixed with coal powder, comprising:

[0029] Step 100: When the thermal storage oxidation device is in the first condition, the first solenoid valve and the fourth solenoid valve are controlled to be opened, and the second solenoid valve and the third solenoid valve are controlled to be closed, so that the air-deficient gas and the target pulverized coal enter the thermal storage oxidation device through the upper input end, and then the flue gas generated by the thermal storage oxidation device enters the energy utilization device through the lower output end; wherein the mass of the target pulverized coal per unit time is determined according to the proportion of the heat generated by the air-deficient gas per unit time;

[0030] Step 200: When the thermal storage oxidizer is in the second condition, the first solenoid valve and the fourth solenoid valve are controlled to be closed, and the second solenoid valve and the third solenoid valve are controlled to be opened, so that the exhaust gas enters the thermal storage oxidizer through the lower input end, the target pulverized coal enters the thermal storage oxidizer through the upper input end, and the flue gas generated by the thermal storage oxidizer enters the energy utilization device through the upper output end;

[0031] Step 300: repeating steps 100 and 200, so that the exhaust gas is mixed with the target pulverized coal and burned in the thermal storage oxidation device, thereby recovering and utilizing heat.

[0032] Optionally, before executing step 100, the method includes:

[0033] The thermal storage oxidation device is preheated by electric heating.

[0034] Optionally, the process of determining the target coal powder mass is as follows:

[0035] According to the formula Calculate the oxidation heat generated when the methane concentration in the exhaust gas is the first concentration per unit time;

[0036] According to the formula Calculating the oxidation heat generated when the methane concentration is a reference concentration per unit time; the first concentration is less than the reference concentration, and the oxidation heat generated when the methane concentration is the reference concentration per unit time can maintain the operation of the thermal storage oxidation device;

[0037] Calculate the oxidation heat difference; the oxidation heat difference is the difference between the oxidation heat generated when the methane concentration in the exhaust gas is the first concentration per unit time and the oxidation heat generated when the methane concentration is the reference concentration per unit time;

[0038] The oxidation heat difference is taken as the heat generated per unit mass of coal powder, and combined with the formula Q2 = q coal-LHV ·m coal Calculate the target coal powder mass that needs to be supplemented;

[0039] Wherein, Q1 represents the oxidation heat generated when the methane concentration in the exhaust gas is the first concentration per unit time, MJ / h;

[0040] Q3 represents the oxidation heat generated when the methane concentration in the exhaust gas is the reference concentration per unit time, MJ / h;

[0041] L represents the flow rate of the exhaust gas treated by the thermal oxidation device, m 3 / h;

[0042] Indicates the concentration of methane in the ventilation gas, vol.%;

[0043] Indicates the lower calorific value of methane, MJ / m 3 ;

[0044] η represents the oxidation rate of methane, %;

[0045] Q2 represents the heat generated by unit mass of pulverized coal, MJ;

[0046] q coal-LHV Indicates the lower calorific value of pulverized coal, MJ / Kg;

[0047] m coal Indicates the mass of target coal powder, kg.

[0048] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0049] The present invention proposes a new idea and technology for the utilization of exhaust gas; by adding high-quality coal powder, the thermal storage oxidation can be stably operated, the minimum methane concentration and oxidation temperature for self-sustaining operation are reduced, and the utilization efficiency of exhaust gas is greatly improved; at the same time, the present invention solves the problem that coal mine exhaust gas and low-concentration gas cannot be directly utilized, and the exhaust gas is converted into thermal energy for power generation and heating, which can greatly improve the utilization efficiency of exhaust gas, effectively solve the contradiction of tight electricity supply in mining areas and the environmental protection pressure of carbon peak and carbon neutrality, and can effectively reduce heating and energy consumption costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0051] Figure 1 This is a structural diagram of the thermal storage oxidation utilization system of the coal mine ventilation air mixed with coal powder of the present invention;

[0052] Figure 2 The present invention is a flow chart of the method for thermal storage and oxidation utilization of coal mine exhaust air mixed with coal powder.

[0053] Explanation of symbols:

[0054] 1-methane gas tank; 2-air compressor; 3-glass rotor flowmeter; 4-mass flowmeter; 5-gas premixing chamber; 6-gas delivery pipeline; 7-coal powder bin; 8-continuous powder supply assembly; 9-blower; 10-coal powder delivery pipeline; 11-coal powder combustion nozzle; 12-insulation layer; 13-heat storage ceramic; 14-combustion chamber; 15-thermocouple; 16-temperature data acquisition module; 17-computer; 18-heat pipe; 19-heat exchange module; 20-steam turbine; 21-heat exchanger; 22-gas outlet; 23-the second input end of the gas delivery pipeline; 24-the second output end of the heat pipe; 25-gas chromatograph; 26-the first pressure reducing valve; 27-the second pressure reducing valve; 28-the first solenoid valve; 29-the second solenoid valve; 30-the third solenoid valve; 31-the fourth solenoid valve; 32-the first valve; 33-the second valve; 34-the third valve; 35-the fourth valve. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] As a high calorific value clean energy, methane is often mixed with combustibles such as hydrogen and dimethyl ether to study its combustion and explosion characteristics. According to relevant literature, adding coal powder particles during combustion has the advantage of enhancing the thermal radiation of methane combustion, and the addition of coal powder will significantly reduce the ignition temperature of methane. Therefore, in view of the characteristics of exhaust gas such as large air volume, low concentration, large flow fluctuation, etc., which are difficult to utilize, and the requirements of thermal storage oxidation thermal countercurrent technology for operating parameters such as methane concentration, a system and method for thermal storage oxidation utilization of coal mine exhaust gas mixed with coal powder are proposed, and the generated heat is recovered through a waste heat boiler for steam turbine power generation, heating and refrigeration, etc. The present invention can not only improve the utilization rate of exhaust gas and alleviate its impact on the greenhouse effect, but also help to form a clean, efficient and economically feasible exhaust gas resource utilization technology, which has broad application prospects.

[0057] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0058] Embodiment 1

[0059] The coal mine exhaust air mixed with coal powder thermal storage oxidation utilization system provided in this embodiment is based on the energy generated when the methane concentration in the exhaust air gas is 1.2%, fully utilizing the exhaust air gas with a methane concentration of less than 0.75% in the coal mine, and adding additional coal powder according to the proportion of heat generated by exhaust air gas of different concentrations, so that the energy generated by the dual fuel of "exhaust air gas + coal powder" reaches the benchmark, thereby realizing the self-sustaining operation of the thermal storage oxidation device and recovering the usable heat energy. In general, when the methane concentration in the exhaust air of the coal mine is stable at 1.2%, the self-sustaining operation of the thermal storage oxidation device can be maintained; but when the exhaust air gas concentration is too low, the methane conversion rate is low, the consumption cost is relatively large, and the self-sustaining time of the thermal storage oxidation device is short, and the heat recovery efficiency is low. The exhaust gas and pulverized coal are burned simultaneously. The addition of high calorific value pulverized coal will increase the soot content during the methane oxidation process, which helps to increase the temperature of the combustion zone and expand the range of the combustion zone, increase the thermal effect of the system, thereby extending the self-heating balance time of the thermal storage oxidation device, reducing the ignition temperature of methane oxidation and the minimum methane concentration that can be used for power generation, thereby greatly improving the methane processing capacity and conversion efficiency.

[0060] like Figure 1As shown, the present embodiment provides a coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system, which includes a ventilation air gas conveying device, a coal powder conveying device, a thermal storage oxidation device and an energy utilization device.

[0061] The air-deficient gas conveying device is connected to the upper input end of the thermal storage oxidation device through the gas conveying pipeline 6 and the first connecting pipe in sequence; the upper output end of the thermal storage oxidation device is connected to the energy utilization device through the second connecting pipe and the heat conducting pipe 18 in sequence; the air-deficient gas conveying device is connected to the lower input end of the thermal storage oxidation device through the gas conveying pipeline 6 and the third connecting pipe in sequence; the lower output end of the thermal storage oxidation device is connected to the energy utilization device through the fourth connecting pipe and the heat conducting pipe 18 in sequence; the pulverized coal conveying device is connected to the upper input end of the thermal storage oxidation device through the fifth connecting pipe; wherein, a first solenoid valve 28 is installed on the first connecting pipe; a second solenoid valve 29 is installed on the second connecting pipe; a third solenoid valve 30 is installed on the third connecting pipe; and a fourth solenoid valve 31 is installed on the fourth connecting pipe.

[0062] The air-deficient methane gas conveying device is used to convey air-deficient methane gas; the coal powder conveying device is used to convey target coal powder; wherein the mass of the target coal powder per unit time is determined based on the proportion of heat generated by the air-deficient methane gas per unit time.

[0063] The thermal storage oxidation device is used to generate flue gas according to the reaction between the exhaust gas and the target pulverized coal; the thermal energy of the flue gas includes a first part of thermal energy, a second part of thermal energy and a third part of thermal energy; the first part of thermal energy is used to maintain the operation of the thermal storage oxidation device; the energy utilization device is used to convert the second part of thermal energy into electrical energy and perform heat exchange operation on the third part of thermal energy;

[0064] During operation, at a first time interval, the first solenoid valve 28 and the fourth solenoid valve 31 are controlled to be opened, and the second solenoid valve 29 and the third solenoid valve 30 are controlled to be closed, so that the air-deficient gas and the target pulverized coal enter the thermal storage oxidizer through the upper input end, and the flue gas generated by the thermal storage oxidizer enters the energy utilization device through the lower output end; at a second time interval, the first solenoid valve 28 and the fourth solenoid valve 31 are controlled to be closed, and the second solenoid valve 29 and the third solenoid valve 30 are controlled to be opened, so that the air-deficient gas enters the thermal storage oxidizer through the lower input end, the target pulverized coal enters the thermal storage oxidizer through the upper input end, and the flue gas generated by the thermal storage oxidizer enters the energy utilization device through the upper output end, and the cycle operation is carried out so that the air-deficient gas is mixed with the target pulverized coal and burned in the thermal storage oxidizer, thereby recovering heat. Wherein, the first time interval and the second time interval are the same.

[0065] As a preferred implementation, the exhaust gas methane conveying device described in this embodiment includes a methane gas tank 1, an air compressor 2 and a gas premixing chamber 5.

[0066] The output end of the methane gas tank 1 is connected to the first input end of the gas premixing chamber 5 through the sixth connecting pipe; the output end of the air compressor 2 is connected to the second input end of the gas premixing chamber 5 through the seventh connecting pipe; the output end of the gas premixing chamber 5 is the output end of the exhaust gas gas conveying device, that is, the output end of the gas premixing chamber 5 and the first input end of the gas conveying pipeline 6.

[0067] Furthermore, according to the gas delivery direction, the sixth connecting pipe is sequentially installed with a second pressure reducing valve 27, a second valve 33, a mass flowmeter 4 and a fourth valve 35, and the seventh connecting pipe is sequentially installed with a first pressure reducing valve 26, a first valve 32, a glass rotor flowmeter 3 and a third valve 34.

[0068] As a preferred implementation, the pulverized coal conveying device described in this embodiment includes a pulverized coal bin 7 , a continuous pulverized coal supply component 8 and a blower 9 .

[0069] The continuous powder supply component 8 is arranged on the output end of the coal powder bin 7; the continuous powder supply component 8 is used to control the output amount of coal powder in the coal powder bin, that is, to control the opening of the coal powder bin; the output end of the coal powder bin 7 is connected to the first input end of the fifth connecting pipe, the blower 9 is connected to the second input end of the fifth connecting pipe, and the output end of the fifth connecting pipe is connected to the upper input end of the thermal storage oxidation device; wherein the fifth connecting pipe here is Figure 1 The pulverized coal conveying pipeline 10 in.

[0070] During operation, the target coal powder is transported into the thermal storage oxidation device through the cooperation of the continuous powder supply assembly 8 and the blower 9.

[0071] As a preferred embodiment, the present embodiment includes a combustion chamber 14, an insulating layer 12 for wrapping the combustion chamber 14, a heat storage ceramic 13 installed in the middle area of ​​the inner cavity of the combustion chamber 14, and a pulverized coal combustion nozzle 11 arranged in the top area of ​​the inner cavity of the combustion chamber 14; the pulverized coal combustion nozzle 11 is connected to the upper input end.

[0072] Furthermore, the present embodiment also provides a temperature monitoring device; the temperature monitoring device includes a thermocouple 15, a temperature data acquisition module 16 connected to one end of the thermocouple 15, and a computer 17 for acquiring temperature information collected by the temperature data acquisition module.

[0073] There are multiple thermocouples 15 , and the other ends of the multiple thermocouples 15 are evenly distributed on the thermal storage ceramic 13 according to vertical distances.

[0074] As a preferred implementation, the energy utilization device described in this embodiment includes a heat exchange module 19 , a steam turbine 20 and a heat exchanger 21 .

[0075] The input end of the heat exchange module 19 is in communication with the first output end of the heat conducting pipe 18 , and the heat exchange module 19 is used to obtain the heat of the flue gas transmitted by the heat conducting pipe 18 to obtain superheated steam and low-temperature steam.

[0076] The first output end of the heat exchange module 19 is connected to the steam turbine 20, and the heat exchange module 19 is used to transmit the superheated steam to the steam turbine 20; the steam turbine is used to generate electricity according to the superheated steam to realize the conversion of thermal energy into electrical energy.

[0077] The second output end of the heat exchange module 19 is connected to the heat exchanger 21; the heat exchange module 10 is used to transmit the low-temperature steam to the heat exchanger 21; the heat exchanger 21 is used to perform heat exchange based on the low-temperature steam to produce hot water, and discharge the cooled water vapor into the atmosphere through the outlet 22.

[0078] Furthermore, the present embodiment also provides a gas chromatograph 25 .

[0079] The first input end of the gas chromatograph 25 is connected to the second output end 24 of the heat pipe 28 through the eighth connecting pipe, that is, the gas detection at the outlet is performed; the second input end of the gas chromatograph is connected to the second input end of the gas delivery pipeline through the ninth connecting pipe, that is, the gas detection at the inlet is performed.

[0080] The gas chromatograph 25 is used to analyze the concentration and composition of the flue gas, as well as the concentration and composition of the ventilation methane gas.

[0081] The specific process of the coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system provided in this embodiment is as follows:

[0082] The methane gas tank 1 and the air compressor 2 control the gas flow entering the gas premixing chamber 5 through the glass rotor flowmeter 3 and the mass flowmeter 4 respectively, and mix the required concentration of exhaust gas methane in the gas premixing chamber 5; the exhaust gas methane of the required concentration enters the thermal storage oxidation device through the gas delivery pipe 6; the amount of coal powder required to be supplemented during the self-sustaining operation of the thermal storage oxidation device is theoretically calculated, that is, the target coal powder is obtained, and then the required amount of coal powder is accurately added through the coal powder bin 7 and the continuous powder supply component 8, and the required amount of coal powder is delivered to the combustion chamber 14 through the coal powder delivery pipe 10 via the blower 9, and a coal powder combustion nozzle 11 is set at the entrance of the combustion chamber 14 to ensure that the coal powder is continuously and stably delivered to the combustion chamber, so as to provide guarantee for the subsequent oxidation reaction; wherein, the coal powder combustion nozzle 11 is connected to the combustion chamber 14 through a flange.

[0083] A combustion chamber 14 is provided in the thermal storage oxidation device so that the pulverized coal and the exhaust gas are fully reacted. A thermal storage ceramic 13 is built in the middle part of the combustion chamber 14. The outer wall of the thermal storage ceramic 13 is wrapped by an insulating layer 12 to reduce the heat dissipation loss of the thermal storage oxidation device. Thermocouples 15 are evenly distributed in the oxidation bed of the thermal storage ceramic 13 according to the vertical distance. One end of the thermocouple 15 is inserted into the combustion chamber 14 to monitor the temperature field change in the combustion chamber 14. The other end of the thermocouple 15 is connected to a temperature data acquisition module 16. The temperature data acquisition module 16 is also connected to a computer 1 7 are connected to read data, so as to realize the monitoring of temperature in the thermal storage oxidation process; the high-temperature flue gas generated by the thermal storage oxidation device enters the heat exchange module 19 through the heat pipe 18 for recycling, the heat exchange module 19 generates superheated steam through the turbine 20 to generate electricity, the heat exchange module 19 generates low-temperature steam through the heat exchanger 21 to generate hot water for heating and heating, etc., the heat exchanger 21 discharges the generated cooled water vapor into the atmosphere through the outlet 22, and uses the gas chromatograph 25 to analyze the composition and concentration of the inlet and outlet gases.

[0084] The control process of the coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system provided in this embodiment is as follows:

[0085] During operation, the thermal storage oxidation device is first preheated by electric heating to reach the ignition temperature required for oxidation of the exhaust gas. Then the corresponding heating device is closed, exhaust gas is introduced, and the first solenoid valve 28 and the fourth solenoid valve 31 are opened at the same time, the reactants burn and heat is exchanged through the thermal storage ceramic 13; as the reaction proceeds, the temperature above the combustion chamber 14 gradually decreases, that is, after the first time interval, the valve is switched, the first solenoid valve 28 and the fourth solenoid valve 31 are closed, the second solenoid valve 29 and the third solenoid valve 30 are opened, and the exhaust gas enters the high-temperature zone below from the lower input end for oxidation combustion; after the second time interval again, the first solenoid valve 28 and the fourth solenoid valve 31 are opened again. With the switching of the solenoid valve, the direction of the exhaust gas entering the thermal storage oxidation device is continuously changed, and the cycle is repeated, so that the exhaust gas mixed with coal powder can be stably burned in the thermal storage oxidation device, thereby recovering heat.

[0086] The process of theoretically calculating the amount of pulverized coal required to be supplemented when the thermal oxidation device is self-sustaining:

[0087] The oxidation heat that methane can generate per unit time:

[0088]

[0089]

[0090] Where, Q1 is the oxidation heat generated when the methane concentration in the exhaust gas is the first concentration per unit time, MJ / h, MJ / h;

[0091] Q3—Oxidation heat generated when the methane concentration in the exhaust gas per unit time is the reference concentration, MJ / h;

[0092] L—Flow rate of exhaust gas treated by thermal oxidation device, m 3 / h;

[0093] —Concentration of methane in ventilation gas, vol.%;

[0094] —Lower calorific value of methane, MJ / m 3 , generally 35.88MJ / m 3 ;

[0095] η—Oxidation rate of methane, %.

[0096] The heat generated by unit mass of pulverized coal:

[0097] Q2=q coal-LHV ·m coal ;

[0098] Where, Q2—heat generated by unit mass of pulverized coal, MJ;

[0099] q coal-LHV —lower calorific value of pulverized coal, MJ / Kg;

[0100] m coal —Mass of coal powder, kg.

[0101] Generally speaking, when the methane concentration in the exhaust gas is 1.2%, the stable operation of the thermal storage oxidation device can be maintained, and the heat generated can also be used for heating and power generation through the heat exchange module; but in reality, the methane concentration in the exhaust gas is generally lower than 0.75%, which cannot be effectively utilized, but is directly discharged.

[0102] Assuming that the methane concentration in the ventilation gas is 0.5%, firstly according to the formula Calculate the oxidation heat generated per unit time when the methane concentration is 0.5%, that is, the first oxidation heat, according to the formula Calculate the oxidation heat generated per unit time when the methane concentration is 1.2%, that is, the second oxidation heat, and calculate the difference between the first oxidation heat and the second oxidation heat; this difference is supplemented by adding coal powder; secondly, the difference is used as the heat generated per unit mass of coal powder, and combined with the formula Q2 = q coal-LHV ·m coal Calculate the amount of coal powder required to be supplemented, that is, the mass of the target coal powder.

[0103] On this basis, it is obvious that this embodiment uses coal mine exhaust air as the main fuel, and preferably uses low-sulfur, low-ash, high-calorific value high-quality pulverized coal as the auxiliary fuel, and mixes it to increase the oxidation heat of the reactants. The exhaust air gas and pulverized coal are passed into the pre-heated thermal storage oxidation device in the form of carrier gas powder delivery for high-temperature oxidation. Part of the released heat is used to maintain the self-sustaining operation of the thermal storage oxidation device, and the other part is recovered in the form of high-temperature flue gas through the waste heat boiler to produce saturated or superheated steam, which can be used for steam turbines to efficiently generate electricity, and can also be used for heating wells in mining areas, underground cooling, heating and bathing, etc., thereby reducing the use of fossil fuels. This embodiment not only helps to improve the comprehensive utilization efficiency of energy, but also effectively reduces the direct discharge of exhaust air gas into the atmosphere, causing a large amount of clean energy waste and damage to the ecological environment, and has the characteristics of economic feasibility.

[0104] Embodiment 2

[0105] In order to achieve the above-mentioned purpose, the present embodiment provides a method for thermal storage oxidation utilization system of coal mine ventilation mixed with coal powder according to the first embodiment, such as Figure 2 As shown, including:

[0106] Step 100: When the thermal storage oxidation device is in the first condition, the first solenoid valve and the fourth solenoid valve are controlled to be opened, and the second solenoid valve and the third solenoid valve are controlled to be closed, so that the air-deficient methane gas and the target pulverized coal enter the thermal storage oxidation device through the upper input end, and then the flue gas generated by the thermal storage oxidation device enters the energy utilization device through the lower output end; wherein, the mass of the target pulverized coal per unit time is determined according to the proportion of heat generated by the air-deficient methane gas per unit time.

[0107] Step 200: When the thermal storage oxidizer is in the second condition, the first solenoid valve and the fourth solenoid valve are controlled to be closed, and the second solenoid valve and the third solenoid valve are controlled to be opened, so that the exhaust gas enters the thermal storage oxidizer through the lower input end, the target pulverized coal enters the thermal storage oxidizer through the upper input end, and the flue gas generated by the thermal storage oxidizer enters the energy utilization device through the upper output end. The first condition is the first time interval, the second condition is the second time interval, and the first time interval and the second time interval are the same.

[0108] Step 300: repeating steps 100 and 200, so that the exhaust gas is mixed with the target pulverized coal and burned in the thermal storage oxidation device, thereby recovering and utilizing heat.

[0109] As a preferred implementation, before executing step 100, this embodiment includes:

[0110] Step 000: preheating the thermal storage oxidation device by electric heating.

[0111] As a preferred implementation, the process of determining the target coal powder mass described in this embodiment is as follows:

[0112] Step A: According to the formula Calculate the oxidation heat generated when the methane concentration in the exhaust gas is the first concentration per unit time.

[0113] Step B: According to the formula The oxidation heat generated when the methane concentration is a reference concentration per unit time is calculated; the first concentration is less than the reference concentration, and the oxidation heat generated when the methane concentration is the reference concentration per unit time can maintain the operation of the thermal storage oxidation device.

[0114] Step C: Calculate the oxidation heat difference; the oxidation heat difference is the difference between the oxidation heat generated when the methane concentration in the exhaust gas is the first concentration per unit time and the oxidation heat generated when the methane concentration is the reference concentration per unit time.

[0115] Step D: Taking the oxidation heat difference as the heat generated per unit mass of coal powder, and combining the formula Q2 = q coal-LHV ·mcoal Calculate the target mass of coal powder that needs to be supplemented.

[0116] Wherein, Q1 represents the oxidation heat generated when the methane concentration in the exhaust gas is the first concentration per unit time, MJ / h;

[0117] Q3 represents the oxidation heat generated when the methane concentration in the exhaust gas is the reference concentration per unit time, MJ / h;

[0118] L represents the flow rate of the exhaust gas treated by the thermal oxidation device, m 3 / h;

[0119] Indicates the concentration of methane in the ventilation gas, vol.%;

[0120] Indicates the lower calorific value of methane, MJ / m 3 ;

[0121] η represents the oxidation rate of methane, %;

[0122] Q2 represents the heat generated by unit mass of pulverized coal, MJ;

[0123] q coal-LHV Indicates the lower calorific value of pulverized coal, MJ / Kg;

[0124] m coal Indicates the mass of target coal powder, kg.

[0125] Compared with the prior art, the present invention has the following technical effects:

[0126] (1) The present invention proposes a new idea and technology for the utilization of exhaust gas; by adding high-quality coal powder to stabilize the thermal storage oxidation operation, the minimum methane concentration and oxidation temperature for self-sustaining operation are reduced, and the utilization efficiency of exhaust gas is greatly improved. Moreover, the blending technology can be extended to low-concentration extracted gas with a concentration of less than 7%, thereby realizing efficient utilization of coal mine gas and zero emissions.

[0127] (2) The oxidation temperature of the exhaust gas of the present invention is controlled below 1000°C, which is lower than the temperature range of 1200°C for the generation of nitrogen oxides, thereby reducing the pollution of nitrogen oxides to the environment; the exhaust gas carries fine particles of coal powder, which can achieve near-zero emissions after oxidation.

[0128] (3) The present invention solves the problem that the lack of air and low-concentration gas in coal mines cannot be directly utilized. The lack of air gas is converted into thermal energy and used for power generation and heating, which can greatly improve the utilization efficiency of the lack of air gas, effectively solve the contradiction of tight power supply in mining areas and the environmental protection pressure of carbon peak and carbon neutrality, and can effectively reduce the cost of heating and energy consumption.

[0129] (4) While effectively treating exhaust gas from coal mines, the present invention can achieve large-scale energy conservation and emission reduction, protect the environment, and obtain carbon emission reduction benefits, changing the current situation where direct exhaust of exhaust gas from coal mines is ineffective. It will surely effectively promote the comprehensive utilization of resources and promote safe production in coal mines.

[0130] (5) The present invention can achieve stable cogeneration of heat and power, thereby replacing the original boiler equipment that has a greater impact on the environment, saving operating costs, and generating economic benefits by outputting heat energy.

[0131] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0132] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A coal mine exhaust air mixed with coal powder thermal storage oxidation utilization system, characterized in that: It includes a ventilation gas conveying device, a pulverized coal conveying device, a thermal storage oxidation device and an energy utilization device; The air-lack gas conveying device is connected with the upper input end of the thermal storage oxidation device through the gas conveying pipeline and the first connecting pipe in sequence; the upper output end of the thermal storage oxidation device is connected with the energy utilization device through the second connecting pipe and the heat conducting pipe in sequence; the air-lack gas conveying device is connected with the lower input end of the thermal storage oxidation device through the gas conveying pipeline and the third connecting pipe in sequence; the lower output end of the thermal storage oxidation device is connected with the energy utilization device through the fourth connecting pipe and the heat conducting pipe in sequence; the pulverized coal conveying device is connected with the upper input end of the thermal storage oxidation device through the fifth connecting pipe; wherein a first solenoid valve is installed on the first connecting pipe; a second solenoid valve is installed on the second connecting pipe; a third solenoid valve is installed on the third connecting pipe; and a fourth solenoid valve is installed on the fourth connecting pipe; The air-deficient methane gas conveying device is used to convey air-deficient methane gas; the pulverized coal conveying device is used to convey target pulverized coal; wherein the mass of the target pulverized coal per unit time is determined according to the proportion of heat generated by the air-deficient methane gas per unit time; The thermal storage oxidation device is used to generate flue gas according to the reaction between the exhaust gas and the target pulverized coal; the thermal energy of the flue gas includes a first part of thermal energy, a second part of thermal energy and a third part of thermal energy; the first part of thermal energy is used to maintain the operation of the thermal storage oxidation device; the energy utilization device is used to convert the second part of thermal energy into electrical energy and perform heat exchange operation on the third part of thermal energy; During operation, the first solenoid valve and the fourth solenoid valve are controlled to be opened, and the second solenoid valve and the third solenoid valve are controlled to be closed, so that the air-deficient methane gas and the target pulverized coal enter the thermal storage oxidation device through the upper input end, and the flue gas generated by the thermal storage oxidation device enters the energy utilization device through the lower output end; the first solenoid valve and the fourth solenoid valve are controlled to be closed, and the second solenoid valve and the third solenoid valve are controlled to be opened, so that the air-deficient methane gas enters the thermal storage oxidation device through the lower input end, and the target pulverized coal enters the thermal storage oxidation device through the upper input end, and the flue gas generated by the thermal storage oxidation device enters the energy utilization device through the upper output end. The cycle operation is carried out so that the air-deficient methane gas is mixed with the target pulverized coal and burned in the thermal storage oxidation device, thereby recovering heat.

2. A coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system according to claim 1, characterized in that: The exhaust gas delivery device comprises a methane gas tank, an air compressor and a gas premixing chamber; The methane gas tank is connected to the gas premixing chamber through a sixth connecting pipe; the air compressor is connected to the gas premixing chamber through a seventh connecting pipe; the output end of the gas premixing chamber is the output end of the exhaust gas gas delivery device; According to the gas delivery direction, the sixth connecting pipe is sequentially installed with a second pressure reducing valve, a second valve, a mass flow meter and a fourth valve, and the seventh connecting pipe is sequentially installed with a first pressure reducing valve, a first valve, a glass rotor flow meter and a third valve.

3. A coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system according to claim 1, characterized in that: The pulverized coal conveying device comprises a pulverized coal bin, a continuous pulverized coal supply assembly and a blower; The continuous powder supply component is arranged on the output end of the coal powder bin; the continuous powder supply component is used to control the output amount of coal powder in the coal powder bin; the output end of the coal powder bin is connected to the first input end of the fifth connecting pipe, the blower is connected to the second input end of the fifth connecting pipe, and the output end of the fifth connecting pipe is connected to the upper input end of the thermal storage oxidation device.

4. A coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system according to claim 1, characterized in that: The thermal storage oxidation device includes a combustion chamber, an insulating layer for wrapping the combustion chamber, thermal storage ceramics installed in the middle area of ​​the combustion chamber inner cavity, and a pulverized coal combustion nozzle arranged in the top area of ​​the combustion chamber inner cavity; the pulverized coal combustion nozzle is connected to the upper input end.

5. A coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system according to claim 4, characterized in that: It also includes a temperature monitoring device; the temperature monitoring device includes a thermocouple, a temperature data acquisition module connected to one end of the thermocouple, and a computer for acquiring temperature information collected by the temperature data acquisition module; There are multiple thermocouples, and the other ends of the multiple thermocouples are evenly distributed on the thermal storage ceramic according to vertical distances.

6. A coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system according to claim 1, characterized in that: The energy utilization device includes a heat exchange module, a steam turbine and a heat exchanger; The input end of the heat exchange module is in communication with the first output end of the heat conducting pipe, and the heat exchange module is used to obtain the heat of the flue gas transmitted by the heat conducting pipe to obtain superheated steam and low-temperature steam; The first output end of the heat exchange module is connected to the steam turbine, and the heat exchange module is used to transmit the superheated steam to the steam turbine; the steam turbine is used to generate electricity according to the superheated steam; The second output end of the heat exchange module is connected to the heat exchanger; the heat exchange module is used to transmit the low-temperature steam to the heat exchanger; the heat exchanger is used to perform heat exchange based on the low-temperature steam to generate hot water.

7. A coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system according to claim 6, characterized in that: Also included is a gas chromatograph; The first input end of the gas chromatograph is connected to the second output end of the heat conducting pipe through an eighth connecting pipe; the second input end of the gas chromatograph is connected to the gas delivery pipeline through a ninth connecting pipe; The gas chromatograph is used to analyze the concentration and composition of the flue gas, and to analyze the concentration and composition of the ventilation methane gas.

8. A method for thermal storage and oxidation utilization of a coal mine ventilation air mixed with coal powder according to any one of claims 1 to 7, characterized in that: include: Step 100: When the thermal storage oxidation device is in the first condition, the first solenoid valve and the fourth solenoid valve are controlled to be opened, and the second solenoid valve and the third solenoid valve are controlled to be closed, so that the air-deficient gas and the target pulverized coal enter the thermal storage oxidation device through the upper input end, and then the flue gas generated by the thermal storage oxidation device enters the energy utilization device through the lower output end; wherein the mass of the target pulverized coal per unit time is determined according to the proportion of the heat generated by the air-deficient gas per unit time; Step 200: When the thermal storage oxidizer is in the second condition, the first solenoid valve and the fourth solenoid valve are controlled to be closed, and the second solenoid valve and the third solenoid valve are controlled to be opened, so that the exhaust gas enters the thermal storage oxidizer through the lower input end, the target pulverized coal enters the thermal storage oxidizer through the upper input end, and the flue gas generated by the thermal storage oxidizer enters the energy utilization device through the upper output end; Step 300: repeating steps 100 and 200, so that the exhaust gas is mixed with the target pulverized coal and burned in the thermal storage oxidation device, thereby recovering and utilizing heat.

9. The method of a coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system according to claim 8, characterized in that: Before executing step 100, the process includes: The thermal storage oxidation device is preheated by electric heating.

10. The method of a coal mine ventilation air mixed with coal powder thermal storage oxidation utilization system according to claim 8, characterized in that: The process of determining the target coal powder quality is as follows: According to the formula Calculate the oxidation heat generated when the methane concentration in the exhaust gas is the first concentration per unit time; According to the formula Calculating the oxidation heat generated when the methane concentration is a reference concentration per unit time; the first concentration is less than the reference concentration, and the oxidation heat generated when the methane concentration is the reference concentration per unit time can maintain the operation of the thermal storage oxidation device; Calculate the oxidation heat difference; the oxidation heat difference is the difference between the oxidation heat generated when the methane concentration in the exhaust gas is the first concentration per unit time and the oxidation heat generated when the methane concentration is the reference concentration per unit time; The oxidation heat difference is taken as the heat generated per unit mass of coal powder, and combined with the formula Q2 = q coal-LHV ·m coal Calculate the target coal powder mass that needs to be supplemented; Wherein, Q1 represents the oxidation heat generated when the methane concentration in the exhaust gas is the first concentration per unit time, MJ / h; Q3 represents the oxidation heat generated when the methane concentration in the exhaust gas is the reference concentration per unit time, MJ / h; L represents the flow rate of the exhaust gas treated by the thermal oxidation device, m 3 / h; Indicates the concentration of methane in the ventilation gas, vol.%; Indicates the lower calorific value of methane, MJ / m 3 ; η represents the oxidation rate of methane, %; Q2 represents the heat generated by unit mass of pulverized coal, MJ; q coal-LHV Indicates the lower calorific value of pulverized coal, MJ / Kg; m coal Indicates the mass of target coal powder, kg.

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