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Project Introduction
To improve coal mine production, large amounts of ventilation are usually used to discharge coal mine gas (called mine exhaustion, Ventilation Air Methane, referred to as VAM). The concentration of methane in the mine exhausted wind is very low (usually less than 1%), and the concentration fluctuation range is large. The use as the main fuel is restricted. Almost all coal mines have not tried to recover and treat the methane in the mine exhausted wind, but directly discharge it into the atmosphere, causing serious pollution problems to the atmospheric environment.
In view of the characteristics of huge wind and wind volume in coal mines, very low gas concentration in coal mines, and large fluctuation range of gas concentration, a coal mine exhaust gas utilization technology was developed, and a vertical wind-heat countercurrent oxidation device was developed to control and utilize mine exhaust gas, reducing methane greenhouse gas emissions caused by coal mine production, and at the same time, the energy in mine exhaust gas was recovered and utilized.
my country's research on the utilization technology of coal mines with low wind gas started late. In recent years, many domestic universities have conducted laboratory research on the mechanisms of catalytic oxidation of low wind gas and thermal countercurrent oxidation, and no industrial prototypes can be developed that can truly demonstrate the operation.
In 2007, Zibo Zichai New Energy Co., Ltd. cooperated with universities to jointly develop a vertical windless gas thermal countercurrent oxidation device. The 40,000m3/h vertical wind-heat countercurrent oxidation device jointly developed by both parties was conducted in the factory in the first half of 2009. The project passed the appraisal and acceptance organized by the Shandong Provincial Economic and Information Technology Commission in December 2009.
In 2010, the 40,000m3/h exhaust oxidation device was conducted on-site tests and demonstration operations in the coal mine.
Our company also undertakes the key projects of the National High-Tech Research and Development Plan (863 Plan) 'Key Technologies and Equipment Development of Coal Mine Flood Gas Separation and Oxidation Utilization'. According to the project plan, a 60,000m3/h vertical Flood Oxidation Device was developed.
Basic Principles of Coal Mine Wind Gas Thermal Reverse Current Oxidation Device
The exhaust gas heat countercurrent oxidation device mainly consists of five parts: the oxidation device body, the gas inlet and outlet distribution system, the heating starting system, the exhaust gas reversing system, and the real-time measurement and control system.
The external heat source (burner) heats the solid oxidation bed of the heat exchange medium to the methane oxidation temperature, introduces the ventilated gas from the mine into the oxidation device, and exchanges heat with the heat exchange medium in the device in the reaction zone. The gas is heated to reach the temperature required for gas combustion, an oxidation reaction (combustion) occurs, and heat is released. After the oxidation reaction is maintained, external heating is stopped. A cycle includes two air flow commutation, and the control system automatically controls parameters such as the commutation time.
Main technical parameters
The gas concentration range for stable operation: 0.3% to 2.0%;
Methane oxidation rate ≥97%;
It can generate superheated steam, the pressure of superheated steam is ≥2.5MPa, the temperature is ≥400℃, and the pressure and temperature fluctuation amplitude is ±5%;
The resistance loss of inlet and outlet gas is ≤4000Pa.
Main technical features of windless gas thermal countercurrent oxidation device of Zichai Coal Mine
The vertical structure is adopted to avoid the problem of uneven temperature distribution caused by natural convection.
The absence of catalysts can avoid catalyst poisoning caused by the mine exhaustion and contains hydrogen sulfide.
A variety of honeycomb ceramics combine oxidation bed structures to improve the oxidation efficiency of exhaust gas, ensure the stable operation of the oxidation device, reduce the gas flow resistance, and extend the service life of the oxidation device.
The gas inlet and outlet distribution technology is adopted, and the gas flow rate entering and exiting the oxidation bed is adjusted in various places to ensure that the exhausted wind enters the oxidation bed evenly.
The external heat source is made by using a burner, which can save a lot of electricity compared to traditional electric heating.
The heat exchanger of constant temperature high-temperature heat source and heat exchanger are used to produce superheated steam, thereby avoiding fluctuations in the parameters of superheated steam and improving the quality of steam.
The high-reliability computer monitoring system centrally controls the various subsystems of the device and performs systematic coordination to ensure the safe and normal operation of the thermal countercurrent oxidation device.
Economic Benefit Analysis
The exhaust gas undergoes an oxidation reaction, converting CH4 into C02, reducing greenhouse gas emissions, and applying for CDM projects, bringing huge economic benefits; the heat generated by the reaction can be used for heating or power generation, and will also produce better economic benefits.
For example: Assume that the methane concentration in the mine is 0.8%, the flow rate is 80,000 m3/h, the investment is about 11 million, and the annual treatment of the mine is 700.8 million m3, the annual greenhouse gas emission reduction of 80,000t C02 equivalents, the annual heat recovery is 149,666.4 GJ, and the annual power generation is about 10 million degrees.
According to the Kyoto Protocol, methane carbon sink trade (CDM) began to be implemented in 2008. If you apply for a CDM project, it will be calculated at US$15/tC02, and the carbon sink index revenue alone can reach US$1.2 million per year.
Project Introduction
To improve coal mine production, large amounts of ventilation are usually used to discharge coal mine gas (called mine exhaustion, Ventilation Air Methane, referred to as VAM). The concentration of methane in the mine exhausted wind is very low (usually less than 1%), and the concentration fluctuation range is large. The use as the main fuel is restricted. Almost all coal mines have not tried to recover and treat the methane in the mine exhausted wind, but directly discharge it into the atmosphere, causing serious pollution problems to the atmospheric environment.
In view of the characteristics of huge wind and wind volume in coal mines, very low gas concentration in coal mines, and large fluctuation range of gas concentration, a coal mine exhaust gas utilization technology was developed, and a vertical wind-heat countercurrent oxidation device was developed to control and utilize mine exhaust gas, reducing methane greenhouse gas emissions caused by coal mine production, and at the same time, the energy in mine exhaust gas was recovered and utilized.
my country's research on the utilization technology of coal mines with low wind gas started late. In recent years, many domestic universities have conducted laboratory research on the mechanisms of catalytic oxidation of low wind gas and thermal countercurrent oxidation, and no industrial prototypes can be developed that can truly demonstrate the operation.
In 2007, Zibo Zichai New Energy Co., Ltd. cooperated with universities to jointly develop a vertical windless gas thermal countercurrent oxidation device. The 40,000m3/h vertical wind-heat countercurrent oxidation device jointly developed by both parties was conducted in the factory in the first half of 2009. The project passed the appraisal and acceptance organized by the Shandong Provincial Economic and Information Technology Commission in December 2009.
In 2010, the 40,000m3/h exhaust oxidation device was conducted on-site tests and demonstration operations in the coal mine.
Our company also undertakes the key projects of the National High-Tech Research and Development Plan (863 Plan) 'Key Technologies and Equipment Development of Coal Mine Flood Gas Separation and Oxidation Utilization'. According to the project plan, a 60,000m3/h vertical Flood Oxidation Device was developed.
Basic Principles of Coal Mine Wind Gas Thermal Reverse Current Oxidation Device
The exhaust gas heat countercurrent oxidation device mainly consists of five parts: the oxidation device body, the gas inlet and outlet distribution system, the heating starting system, the exhaust gas reversing system, and the real-time measurement and control system.
The external heat source (burner) heats the solid oxidation bed of the heat exchange medium to the methane oxidation temperature, introduces the ventilated gas from the mine into the oxidation device, and exchanges heat with the heat exchange medium in the device in the reaction zone. The gas is heated to reach the temperature required for gas combustion, an oxidation reaction (combustion) occurs, and heat is released. After the oxidation reaction is maintained, external heating is stopped. A cycle includes two air flow commutation, and the control system automatically controls parameters such as the commutation time.
Main technical parameters
The gas concentration range for stable operation: 0.3% to 2.0%;
Methane oxidation rate ≥97%;
It can generate superheated steam, the pressure of superheated steam is ≥2.5MPa, the temperature is ≥400℃, and the pressure and temperature fluctuation amplitude is ±5%;
The resistance loss of inlet and outlet gas is ≤4000Pa.
Main technical features of windless gas thermal countercurrent oxidation device of Zichai Coal Mine
The vertical structure is adopted to avoid the problem of uneven temperature distribution caused by natural convection.
The absence of catalysts can avoid catalyst poisoning caused by the mine exhaustion and contains hydrogen sulfide.
A variety of honeycomb ceramics combine oxidation bed structures to improve the oxidation efficiency of exhaust gas, ensure the stable operation of the oxidation device, reduce the gas flow resistance, and extend the service life of the oxidation device.
The gas inlet and outlet distribution technology is adopted, and the gas flow rate entering and exiting the oxidation bed is adjusted in various places to ensure that the exhausted wind enters the oxidation bed evenly.
The external heat source is made by using a burner, which can save a lot of electricity compared to traditional electric heating.
The heat exchanger of constant temperature high-temperature heat source and heat exchanger are used to produce superheated steam, thereby avoiding fluctuations in the parameters of superheated steam and improving the quality of steam.
The high-reliability computer monitoring system centrally controls the various subsystems of the device and performs systematic coordination to ensure the safe and normal operation of the thermal countercurrent oxidation device.
Economic Benefit Analysis
The exhaust gas undergoes an oxidation reaction, converting CH4 into C02, reducing greenhouse gas emissions, and applying for CDM projects, bringing huge economic benefits; the heat generated by the reaction can be used for heating or power generation, and will also produce better economic benefits.
For example: Assume that the methane concentration in the mine is 0.8%, the flow rate is 80,000 m3/h, the investment is about 11 million, and the annual treatment of the mine is 700.8 million m3, the annual greenhouse gas emission reduction of 80,000t C02 equivalents, the annual heat recovery is 149,666.4 GJ, and the annual power generation is about 10 million degrees.
According to the Kyoto Protocol, methane carbon sink trade (CDM) began to be implemented in 2008. If you apply for a CDM project, it will be calculated at US$15/tC02, and the carbon sink index revenue alone can reach US$1.2 million per year.
