基于Aspen Plus的煤炭空气部分气化联合循环发电系统模拟
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摘要
煤炭空气部分气化联合循环发电技术采用循环流化床反应器作为气化炉和燃烧炉,煤由给料装置送入气化炉中与空气发生反应,产生燃气然后送入燃气轮机中发电;反应剩余的半焦则送入循环流化床燃烧炉中燃烧发电。本文采用甘肃华亭煤为设计煤种,利用Aspen Plus软件对煤炭空气部分气化联合循环发电技术进行模拟研究,得出了空气煤比、碳转化率对气化温度、燃气组分、燃气热值、气化效率、发电效率等因素的影响。结果表明:随着空气煤比的增大,气化温度升高,燃气热值、发电效率及气化效率降低;随着碳转化率增大,燃气的热值提高,气化效率及发电效率均增加;系统发电效率随着碳转化率增加而增加,然而当碳转化率大于80%时,发电效率的增加幅度大幅减小,因此将碳转化率选为80%较为合适,此时的发电效率约为57%,这相较于现有的煤粉燃烧发电系统有极大的提高。
Combined-cycle power generation technology of coal/air partial gasification uses the circulating fluidized bed(CFB) reactor as a gasifier and a combustion furnace. Coal is fed into the gasifier by the feed device and reacts with the air to produce gas which is then sent to the gas turbine for power generation. And the remaining semicoke is then fed to the circulating fluidized bed combustion furnace for combustion and power generation. This study uses Gansu Huating coal as design coal. And a simulation study on combined-cycle power generation technology of coal/air partial gasification is conducted by using Aspen Plus. The effects of air-coal ratio, carbon conversion rate on factors such as gasification temperature, gas composition, gas calorific value, gasification efficiency and power generation efficiency are studied. The results show that, when the air-coal ratio increases, gasification temperature increases and the gas calorific value, power generation efficiency and gasification efficiency decreases. Both the gasification efficiency and power generation efficiency increases when the carbon conversion rate increases. The system power generation efficiency increases with the increasing of the carbon conversion rate. However, the carbon conversion rate is greater than 80%, the increment of power generation efficiency is reduced dramatically. Therefore, it is appropriate to select the carbon conversion as 80%, and at this time the power generation efficiency is around 57%, which is much more than the efficiency of the existing pulverized coal-fired power generation plant.
Combined-cycle power generation technology of coal/air partial gasification uses the circulating fluidized bed(CFB) reactor as a gasifier and a combustion furnace. Coal is fed into the gasifier by the feed device and reacts with the air to produce gas which is then sent to the gas turbine for power generation. And the remaining semicoke is then fed to the circulating fluidized bed combustion furnace for combustion and power generation. This study uses Gansu Huating coal as design coal. And a simulation study on combined-cycle power generation technology of coal/air partial gasification is conducted by using Aspen Plus. The effects of air-coal ratio, carbon conversion rate on factors such as gasification temperature, gas composition, gas calorific value, gasification efficiency and power generation efficiency are studied. The results show that, when the air-coal ratio increases, gasification temperature increases and the gas calorific value, power generation efficiency and gasification efficiency decreases. Both the gasification efficiency and power generation efficiency increases when the carbon conversion rate increases. The system power generation efficiency increases with the increasing of the carbon conversion rate. However, the carbon conversion rate is greater than 80%, the increment of power generation efficiency is reduced dramatically. Therefore, it is appropriate to select the carbon conversion as 80%, and at this time the power generation efficiency is around 57%, which is much more than the efficiency of the existing pulverized coal-fired power generation plant.
引文
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[10]于扬洋,林伟荣,肖平,等.煤热解分级转化热电油天然气多联产系统技术经济性分析[J].热力发电,2017,46(9):8-16.YU Yangyang,LIN Weirong,XIAO Ping,et al.Technoeconomic evaluation for coal-based polygeneration system of heat,power,oil and synthetic natural gas[J].Thermal Power Generation,2017,46(9):8-16.
[11]王俊琪,方梦祥,骆仲泱,等.煤的空气、水蒸气部分气化特性研究[J].热力发电,2008,37(1):21-25.WANG Junqi,FANG Mengxiang,LUO Zhongyang,et al.Study on partial gasification of coal with air and steam[J].Thermal Power Generation,2008,37(1):21-25.
[2]YE C,WANG Q,LUO Z,et al.Characteristics of coal partial gasification on a circulating fluidized bed reactor[J].Energy and Fuels,2017,31(3):2557-2564.
[3]刘耀鑫,李润东,杨天华,等.流化床常压空气部分气化和半焦燃烧的试验研究[J].中国电机工程学报,2008,28(11):11-17.LIU Yaoxin,LI Rundong,YANG Tianhua,et al.Experimental study on combining partial gasification with air on a fluidized bed at atmospheric pressure and semicoke combustion[J].Proceedings of the CSEE,2008,28(11):11-17.
[4]ZHANG G,YANG Y,JIN H,et al.Proposed combinedcycle power system based on oxygen-blown coal partial gasification[J].Applied Energy,2013,102(2):735-745.
[5]肖睿,金保升,欧阳嘉,等.空气鼓风流化床煤部分气化炉煤气成分与热值试验[J].动力工程,2004,24(3):416-420.XIAO Rui,JIN Baosheng,OUYANG Jia,et al.Experimental research on gas composition and heating value in an air-blown fluidized bed gasifier[J].Power Engineering,2004,24(3):416-420.
[6]向银花,房倚天,张守玉,等.煤焦部分气化、燃烧集成热重分析研究[J].燃料化学学报,2000,28(5):435-438.XIANG Yinhua,FANG Yitian,ZHANG Shouyu,et al.Thermogravimetric analysis for coal char partial gasification and combustion[J].Journal of Fuel Chemistry and Technology,2000,28(5):435-438.
[7]王俊琪,方梦祥,刘耀鑫,等.煤的部分空气气化联合循环发电系统特性研究[J].能源工程,2004(3):1-4.WANG Junqi,FANG Mengxiang,LIU Yaoxin,et al.Research about partial air gasification combined cycle system performance of coal[J].Energy Engineering,2004(3):1-4.
[8]YE C,WANG Q,LUO Z,et al.Influence of reactant atmospheres and temperature on mechanism of gasification of coal char derived from lignite[J].Energy Technology,2016,4(6):722-728.
[9]ZHANG R,LIU D,WANG Q,et al.Coal char gasification on a circulating fluidized bed for hydrogen generation:experiments and simulation[J].Energy Technology,2015,3(10):1059-1067.
[10]于扬洋,林伟荣,肖平,等.煤热解分级转化热电油天然气多联产系统技术经济性分析[J].热力发电,2017,46(9):8-16.YU Yangyang,LIN Weirong,XIAO Ping,et al.Technoeconomic evaluation for coal-based polygeneration system of heat,power,oil and synthetic natural gas[J].Thermal Power Generation,2017,46(9):8-16.
[11]王俊琪,方梦祥,骆仲泱,等.煤的空气、水蒸气部分气化特性研究[J].热力发电,2008,37(1):21-25.WANG Junqi,FANG Mengxiang,LUO Zhongyang,et al.Study on partial gasification of coal with air and steam[J].Thermal Power Generation,2008,37(1):21-25.