| China is rich in coal resources.However,low comprehensive utilization and high-polluting utilization methods such as direct coal combustion are still common.In order to realize the clean,high-efficiency and low-carbon utilization of coal,this article combines pulverized coal with oxygen-enriched partial gasification and semi-coke combustion to achieve graded and qualitative utilization of gas and electric power,a simulation study on polygeneration transformation of a 300 MW pulverized coal boiler was carried out,in order to provide theoretical guidance for its industrial application.First,this paper use the Aspen Plus software to model coal gasification and semi-coke combustion processes,and a comparative test is carried out based on the 75kg?h-1pulverized coal pyrolysis and gasification test platform independently designed and built by Zhejiang University.The results show that the model is good for coal gasification products.The distribution forecast is more accurate,which can play a guiding significance for actual production.Then this paper use this model to study the effects of oxygen-to-coal ratio,oxygen concentration,furnace operating parameters and coal type on the coal gasification results.The results show that within the simulation range,increasing the oxygen-to-coal ratio can significantly increase the gas production rate,cold gas efficiency and carbon conversion rate;increasing the oxygen concentration can significantly increase the effective gas ratio and gas calorific value;coal gasification cold gas efficiency and carbon conversion rate using Mongolian blended coal and Ximeng lignite as raw materials are higher,and semi-coke using Shenhua bituminous coal and Gongyi anthracite as raw materials The calorific value is high;the furnace preheating temperature and initial pressure have little effect on the coal gasification result.Subsequently,the three factors of oxygen-to-coal ratio,oxygen concentration and coal type were selected for orthogonal simulation analysis,and the following conclusions were drawn:In order to produce high-quality coal gas,Mongolian blended coal or Gongyi anthracite should be selected,0.2 kg·kg-1 to 0.5 kg·kg-1 oxygen-to-coal ratio and 100%oxygen concentration;to produce high-quality semi-coke,Shenhua bituminous coal should be selected,0.3 kg·kg-1 oxygen-to-coal ratio and 100%oxygen concentration;to improve the coal gasification cold gas For efficiency,choose Mongolian blended coal or Ximeng lignite,0.5 kg·kg-1 oxygen to coal ratio and 50%to 100%oxygen concentration.Finally,this paper reform a 300 MW power plant in China with the polygeneration process,and design a gas and power polygeneration system with the oxygen-enriched partial gasification of pulverized coal as the core,and then analyze the economic benefit of the polygeneration system,explore the best economic benefits,do the uncertainty analysis and the expansive research from the economic point of view,have drawn the following conclusions:under the premise that Shenfu Dongsheng Coal is the design coal,when the oxygen-to-coal ratio is 0.65 kg·kg-1,the system economic benefits The best,at this time the internal rate of return is as high as 22.51%,and the SPP and DPP are only 5.08 years and 6.31 years respectively;the priority order of coal selection is:Gongyi anthracite>Shenhua bituminous coal>Mongolian blended coal>Shenfu Dongsheng coal;the fluctuation of gas price has the greatest impact on economic benefits,followed by the price of raw coal,the price of on-grid electricity and the cost of oxygen production.The polygeneration transformation scheme in this paper has good scalability.The research results of this paper provide a reliable reference for our country to build a polygeneration system with oxygen-enriched partial gasification of pulverized coal as the core. |
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