The Energy Utilization In The Production Of Acetylene By Plasma Pyrolysis Of Coal

The production of acetylene by plasma pyrolysis of coal is a direct conversion from coal, and has the advantages of short flow-sheet, low resources consumption and environmentally friendliness. Obviously, the waste heat of pyrolysis gas in the process needs to be utilized for economic significance. Since acetylene begins to dissociate below 1800K, pyrolysis gas needs quenching, which brings harm to energy use and heat recovery. Thus, this thesis focuses on the waste heat recovery of the quenched pyrolysis gas and the utilization of chemical energy by using appropriate quenching agents.Based on the pilot plant in Xinjiang province, one heat exchanger network was proposed under the condition that the temperature of the quenched gas is 90℃. Furthermore, the key heat exchanger, evaporation-type air cooler, was designed, and has been successfully used in the pilot plant.To improve the heat recovery, another heat exchanger network was proposed under the condition that the temperature of the quenched gas is 250℃. Compared to the process of 90℃, it reduces the quantity of quenching water, improves the grade of the waste heat recovered, and is of convenience for the disposal of the corresponding solid wastes. A special heat exchanger, which can be used under the condition that dust and tar both exist, was designed and has been installed in the lab.To further improve the grade of recovered energy and the recovery rate, two new heat exchanger networks, which could change the heat energy of pyrolysis gas to chemical energy, were proposed using pulverized coal and methane as the quenching agents, respectively. Based on the reaction kinetic models and the actual conditions of the pilot plant, the appropriate equilibrium temperatures of reaction were determined and the corresponding quenching processes were given and discussed.