Analysis of Operational Characteristics of Energy Research and Information Underground Coal Gasification Generator Set He Guangyan Li Zong 2 (1. College of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221008, China; 2. School of Power Engineering, Nanjing Normal University, Nanjing 210042, China) Industrialization of Chemical Power Generation test. The analysis method is used to study the operating parameters and operating characteristics of the underground coal gasification generating unit, and the main links of the damage are obtained. The underground integrated gasification combined cycle (UIGCC) power generation technology using advanced gas turbine is further proposed to effectively improve the underground. The gas utilization rate of gasification gas provides a technical basis for the promotion and application of underground coal gasification power generation technology. China is a big country in coal production and consumption. At present, coal provides about 75% of China's primary energy. Although our country is currently adjusting the energy structure and adding the proportion of other energy sources other than coal, it is predicted that coal will be produced in the next few decades. It will still be China's main primary energy source. In the process of coal development and utilization, due to the backwardness of traditional coal production and utilization methods, the waste of coal resources and the destruction of the ecological environment in China are very serious, which not only restricts the development of the national economy, but also endangers the ecological balance and human survival. China's energy consumption is 8% to 9% of the world's total consumption, while S2 emissions account for 15.1% of the world's total emissions, NOx accounted for 10.1%, and C2 accounted for 13.5%. China's pollutant emissions in S2 87 %, 71% of C2, 67% of NOx and 80% of soot are caused by coal combustion. China's annual output of nearly 1.4 billion tons of coal for direct combustion production of power and thermal energy fuel coal (ie, power coal) accounted for about 4/5. The proportion of thermal coal used for raw coal consumption in China's raw coal production accounted for roughly 20 before 1986 %, added to 30% in 1997, is estimated to exceed 35% in 2005. With the rapid development of China's national economy, China's annual coal output continues to increase. In 2002, China's coal output was 1.3 billion tons, and market demand exceeded 1.4 billion tons. According to the China Coal Industry Association, the total demand for coal in China will reach 1.7 billion tons in 2004. The energy structure with coal as the primary primary energy has caused serious pollution to China's atmospheric environment. China has 2/3 The above cities have exceeded the air pollution and one third of the country has been affected by acid rain. In order to alleviate the pressure of China's existing energy structure on China's environmental protection, develop and utilize different forms of new and renewable energy, and increase the proportion of new and renewable energy in China's energy structure. Sustainable development has important strategic implications. Due to the needs of the coal mining process and the limitations of geological conditions, a large amount of coal will be left in the coal mining process. In order to fully recover the remaining coal resources and utilize the energy of the remaining coal, China has conducted extensive and in-depth research on underground coal gasification in recent years, and achieved success, reaching the practical stage of underground coal gasification project. China has successfully operated more than 10 coal underground gasification furnaces, and the underground coal gasification products produced are used as civilian fuels. Therefore, it is of great value to study the rational purification process of coal underground gasification products and the optimal operation measures of power generation systems to promote the industrialization of coal underground gasification products and improve the primary energy structure of China. 1 The composition and calorific value of underground coal gasification products are on-site sampled and analyzed according to the final gas products of the underground coal gasifiers of Suncun Mine and Ezhuang Mine belonging to Xinwen Mining Group, and the corresponding main underground coal products The ingredients are shown in Table 1. Table 1 The main components of coal underground gasification gas in Suncun Mine and Ezhuang Mine The sampling data of Suncun Ezhuang indicates that underground gasification gas is a kind of clean fuel, and its main combustible components are hydrogen, carbon monoxide and methane. The main components of the underground gasification gas of Suncun Mine are H2, CO2 and N2, of which the content of hydrogen is high, about 20%~52%. The calorific value is about the low quality of hydrogen and the high calorific value, which is 2.73 of the low calorific value of gasoline. Double, but because of the relative molecular mass and light weight, its nominal volumetric calorific value is only 10.8Mm-3, and the theoretical mixed gas with air is only 3.184Mm-3, which is close to biogas and lower than natural gas and carbon monoxide. . But hydrogen is a clean fuel, the combustion product is water, there is no carbon and soot; hydrogen has a wide ignition limit (combustion in air is 4.1% 75%), much larger than gasoline and diesel, can be burned thinly, to reduce The energy consumption rate of the engine under partial load is important; and it has a high flame propagation speed of up to 2.91ms-1, which is 7.72 times that of gasoline and 87% higher than acetylene. It is resistant to explosion when burning in a gasoline engine. Sex is better than gasoline; the ignition energy of hydrogen is lower, the minimum can be as low as 0.013m0.020m, much lower than gasoline. Although the volumetric calorific value of carbon monoxide is low, the theoretical mixed gas calorific value is the highest among the common combustible gases (see Table 2). Table 2 Comparison of the calorific value of several gas fuel theoretical mixed gases. Fuel type theoretical air-fuel ratio / kg-kg-1 nominal volume calorific value / M-Nm-3 theoretical mixture gas calorific value / M-Nm-3 natural gas biogas Chemical Residual Gas Hydrogen Carbon Monoxide 2 Underground Coal Gasification Gas Generator Sets In gas power generation systems that use coal underground gasification products as fuel, gas turbines or internal combustion engines are usually used. Since there is no mature gas turbine for coal underground gasification in China, Xinwen Mining Group adopts a 400kW internal combustion engine generator set with a total of 12 cylinders arranged in a double row, sharing a crankshaft and a V-shaped arrangement. The combustion process has the following characteristics: (1) the mixed gas is formed outside the cylinder, the mixed gas is homogeneous, single phase, and pre-prepared before combustion; (2) the excess air coefficient range is relatively narrow, generally a=0.90~1.20, the unit If the value of 1.1.a is too large, the ignition is unstable, and it is easy to catch fire (not catching fire) when it is partially loaded. If it is too small, it will not burn completely, the gas consumption rate is high and the sewage is serious; the hydrogen content in the gas is high (up to 60) %), in order to prevent deflagration, by automatically adjusting the gas to air ratio, the control cylinder temperature is always lower than the gas ignition point to ensure that no detonation occurs; the combustion process is premixed combustion, with constant volume combustion, the highest combustion temperature is higher; The gas calorific value adaptability is strong, the lowest calorific value in operation can be relaxed to 6.3M.Nm-3; the compression ratio is relatively low, the general gasoline engine is 79, which determines the thermal efficiency of the combustion process is lower, the exhaust gas temperature is higher (due to expansion insufficient). The unit adopts electric control external mixing air intake system, the gas inlet pressure drop is 500kPa, and the pressurized gas stored in the gas cabinet can be directly used, which saves the compression system and the electric injection valve, and the investment is reduced, the operation is simple, and the management is easy. It saves unit power consumption and improves unit efficiency. The test instruments used are: TT4G thermal resistance temperature transmitter, EL4C electrical parameter comprehensive tester, LZB-10 rotor flow test parameters are: oil cooler inlet and outlet water temperature, cooling water flow, engine inlet and outlet water temperature, water flow, Cylinder wall temperature (12 measuring points), generator current, voltage, power. In addition, samples were taken to measure the temperature, composition, and gas composition of the products of combustion. 4 Experimental data analysis The generator sets of Suncun Mine and Ezhuang Mine are the same, so the experimental research of Suncun Mine generator set is selected. The gas generator set is divided into three subsystems: mixer, combustion chamber and piston cylinder device for analysis. Based on the full-day operating conditions of the Suncun Mine generator set on May 23, 2002, the analysis was carried out. At 7:00 on the same day, 7:15 to the experimental results show that the unit heat generation rate is 11478k.kWh-1, the net heat generation efficiency is 28.9%, and the net unit consumption is 1.32m3.kWh-1. The system smoke and energy analysis results are thus available (see Table 3, Table 4). It can be seen that the unit efficiency is 28.3%, the energy utilization rate is low, and it has not been effectively utilized. The losses are mainly concentrated in the three aspects of energy conversion during combustion, large temperature difference heat transfer during engine cooling and heat dissipation, and excessive exhaust gas temperature. Table 3W Analysis Results Summary Name Loss/k Transfer Efficiency/% Smoke Loss Coefficient Mixer Input and Output Combustion Chamber Input and Output Piston Cylinder Input and Output Total Efficiency Total Loss Factor Table 4 Energy Analysis Results Summary Name Energy/k Heat Loss/% Total Energy Combustion Room exhaust sensible heat dissipation work piston cylinder exhaust sensible heat dissipation total heat loss /% total thermal efficiency /% According to the analysis point of view, the loss of gas and air premixing process is small, can be neglected. The premixed gas combustion process is a highly irreversible process with a loss coefficient of up to 0.585, which is the biggest loss in the system. The loss is mainly concentrated on the conversion of chemical energy into flue gas heat energy and part of the energy taken away by the cooling water. The smoke loss coefficient of the combustion-generating flue gas in the piston cylinder device is 0.132, which is mainly caused by the heat conversion into work, the energy in the exhaust gas is not effectively utilized, and the cooling water jacket is cooled. According to the analysis, the mechanical incomplete combustion heat loss and the chemical incomplete combustion heat loss are negligible due to the relatively complete combustion. The heat loss is mainly due to heat loss, up to 49.8%, of which 40.5% are in the combustion chamber (including the piston top) and the remaining 9.3% are in the piston cylinder device. The heat loss is mainly caused by the engine water-cooled interlayer and the oil cooler. Since the unit has not been able to fully utilize the residual heat of flue gas, the exhaust gas temperature is as high as 470C, so the heat loss of exhaust gas is relatively large, 19.4%. It should be noted that although the analysis and energy analysis indicate the loss of combustion process in the premixed gas in the combustion chamber. The biggest, but their analysis is different. The analysis indicates that the loss is mainly composed of two parts, one is the smoke loss caused by the irreversibility of the combustion reaction; the other is the smoke loss caused by the large temperature difference heat transfer of the water-cooled interlayer of the engine. The average temperature of the interlayer effluent is about 62C. Although the heat dissipation is large, but the value contained therein is low, and the heat is finally released to the environment and is not utilized, it causes a large loss. However, the loss of smoke mainly lies in the heat exchange temperature difference, and the heat loss lies in the amount of heat dissipation. During the experiment, the operating conditions of the unit were stable, the combustion conditions were basically good, and all parameters were within the normal working range. This shows that underground gasification gas power generation technology is feasible, not only broadens the utilization route, but also has good environmental protection and safety. The Suncun Gas Generator Set project has an investment of 2 million yuan, including 300,000 yuan for civil works, 1.33 million yuan for equipment and 370,000 yuan for materials. According to the price of electricity, it is only arranged to operate in the peak section of the electricity price, with an annual generating capacity of 1.4 million kWh to 0.55 yuan. The electricity price of kWh-1 is calculated, the output value is 770,000 yuan, and the power generation cost is 0.25 yuan. kWh-1, annual profit of 420,000 yuan, the total investment is expected to be fully recovered within 6 years. 5 Looking forward to the low energy conversion efficiency of existing underground gasification gas generator sets, which needs to be improved, and the underground integrated gasification combined cycle (UIGCC) power generation technology using advanced gas turbines can effectively improve the energy utilization rate of underground gasification gas, which is the future. One of the main development directions of underground gasification gas power generation. The underground gasification gas in Suncun Mine has a high hydrogen content, so the integrated gasification fuel cell combined cycle (IGFC-CC) is another important development direction to improve the energy utilization rate of underground gasification gas. The existing gas generator sets can be modified from several aspects to improve the operation efficiency of the unit: set up high-efficiency waste heat boilers to supply domestic hot water and winter heating, and if necessary, supplemental combustion to fully utilize the heat contained in the unit's exhaust fumes; The effluent of the sandwich and oil cooler is connected to the waste heat boiler, and the heat is also utilized to further improve energy utilization. The level of automation of existing unit monitoring and control needs to be improved, which has a certain impact on the economics of the unit. Due to the large fluctuation of gas calorific value and composition, especially hydrogen content, a special automatic monitoring system is developed for gas generator sets to improve the monitoring level of the unit, adjust the thermal parameters in time, effectively burn the organization, improve the energy utilization, and improve the existing machine. 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