Investigation And Engineering Design Of Oxy-thermal Calcium Carbide Poly-generation System

In China,the primary energy sources is coal-based.Since today's grim international situation,considering the coal as a strategic resource should be actively encouraged and vigorously developed,in order to reduce the dependence on imported raw materials.The traditional coal chemical industry is low resources utilization and high environmental pollution,so how to solve these problems has become the key to promote the development of coal chemical industry.Supported by the National Key Fundamental Development Plan 973,this paper focus on calcium carbide's production process by coal-based oxy-thermal method,including coal-based chemical preparation system and the dynamic system integration,energy conversion and coupling process of the reaction process.To achieve the aim of developing a new type of coal chemical process with low energy consumption,low material consumption and low pollution,we proposed coal-based chemicals/power co-generation system,which combines the production of calcined acetylene and dimethyl ether by oxy-thermal,and fuel cell/steam combined cycling power generation.Combined with the intern experience of chemical design institute,the system has been systematically designed.The main contents of this paper are as follows:Firstly,the oxy-thermal process of carbide acetylene was established,and the flow was simulated by Aspen plus software.The calcium carbide furnace reactor(complex bed reactor),developed by BUCT,was divided into three parts according to the reactor function,which were raw materials preheating/decomposing part?reaction with energy supplyment part and calcium carbide generation part.The material balance and energy balance data of the process are obtained on the basis of reliable verification model.Then,the energy flow graph of the system is drawn based on the energy balance data.Next,the feed and furnace gas composition and system energy utilization were analyzed according to the simulation results.It was found that calcium source was completely transformed into the target product CaC2 and it was found that not only the calcium source was completely transformed into the target product CaC2,but also the sensible/latent heat of reaction and calcium carbide furnace gas can fully meet the needs of calcium carbide generation and preheating of raw materials,when the molar ratio of coke to calcium hydroxide was 9.2:1 and the corresponding mass ratio was 1.5:1.Energy was fully utilized without loss.Secondly,formulated the utilization of furnace gas,this paper put forward the reforming syngas once through the dimethyl ether synthesis reactor,CO only get one-way reaction,and put unreacted syngas into the gas/steam combined cycle power plant for power utilization,constructed the furnace gas based DME/power cogeneration system process.Based on the reliability of the model,the material balance and energy balance data are obtained.According to the simulation results,the energy analysis of the system is carried out.The calculation results show that this system can save about 7%energy consumption compared with the original one step system of dimethyl ether.In the end,the system engineering design of the poly-generation system of calcium carbide production by oxygen thermal method was carried out.According to the yield of ten thousand tons/year of calcium carbide,the corresponding calculation process(material balance,heat balance,pipe diameter calculation and equipment selection etc.);Design Institute in accordance with the standards and requirements,drawing the piping and instrumentation diagrams,equipment layout,piping layout;and the system for economic analysis and safety and environmental protection measures.Based on this,it can provide the basis and guidance for the industrialization of coal oxy-thermal calcium carbide.