低温甲醇洗工艺的模拟及扩产改造的研究
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摘要
某工厂低温甲醇洗工艺原料气分为2股,现有扩产的需求。为实现低温甲醇洗工艺扩产目的,采用Aspen Plus软件基于PSRK物性方法对工艺的实际工况进行了模拟,得到的模拟值与实际值较为符合,从而确定了PSRK为低温甲醇洗工艺模拟的物性方法。在此基础上提出了一种改造方案:新增2台换热器用来预冷原料气;新增氮气汽提塔用来汽提吸收塔甲醇所溶解的酸性气体,甲醇的温度和甲醇中CO2的摩尔分数得以降低,因此甲醇的吸收能力有了明显提高;新增1台进料泵用于输送汽提后的甲醇到吸收塔。同时通过灵敏度分析确定出了改造工艺的最优参数:N2进料量为300 kmol/h,理论板数为7,分流比为0. 020。经过以上改造,各产品流股均符合工艺要求,达到扩产20%的目的。对改造后工艺的操作弹性做进一步分析表明最大扩产幅度可达26%,为实际扩产提供了一定裕度。
There are two feed gas streams in the rectisol stage in a certain plant that plans to expand production.To achieve expansion in the rectisol stage,the actual working condition of this original rectisol process is simulated by using Aspen Plus on the basis of PSRK property method. Because the simulation values match well with the actual operation data,PSRK is determined as the optimal property method for rectisol simulation.Hence,a revamping scheme is proposed as follows: two additional heat exchangers are used to precool feed gas,a new nitrogen stripping tower is also added to strip the dissolved acid gas contained in the methanol in the absorbing tower and a new pump is added to transport stripped methanol into the absorbing tower. Therefore,both the temperature of methanol and the content of CO2 in the methanol are reduced,which leads to an obviously increasing absorption capacity of methanol. Meanwhile,the optimal parameters are determined by sensitivity analysis as follows: feed flow of N2 is 300 kmol·h-1,number of theoretical plates is 7 and split ratio is 0. 020. After these innovations,various product streams conform to process requirements and the20% expansion target is achieved.Finally,the operation flexibility analysis on revamped process shows that the maximum capacity can be expanded by 26%,providing a margin for actual expansion.
There are two feed gas streams in the rectisol stage in a certain plant that plans to expand production.To achieve expansion in the rectisol stage,the actual working condition of this original rectisol process is simulated by using Aspen Plus on the basis of PSRK property method. Because the simulation values match well with the actual operation data,PSRK is determined as the optimal property method for rectisol simulation.Hence,a revamping scheme is proposed as follows: two additional heat exchangers are used to precool feed gas,a new nitrogen stripping tower is also added to strip the dissolved acid gas contained in the methanol in the absorbing tower and a new pump is added to transport stripped methanol into the absorbing tower. Therefore,both the temperature of methanol and the content of CO2 in the methanol are reduced,which leads to an obviously increasing absorption capacity of methanol. Meanwhile,the optimal parameters are determined by sensitivity analysis as follows: feed flow of N2 is 300 kmol·h-1,number of theoretical plates is 7 and split ratio is 0. 020. After these innovations,various product streams conform to process requirements and the20% expansion target is achieved.Finally,the operation flexibility analysis on revamped process shows that the maximum capacity can be expanded by 26%,providing a margin for actual expansion.
引文
[1]唐宏青.低温甲醇洗净化技术[J].中氮肥,2008,(1):1-7.
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[6]钱华光,张述伟,管凤宝,等.低温甲醇洗装置工艺模拟及改造研究[J].大氮肥,2012,35(4):222-224.
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[9]蒋燕,马炯.低温甲醇洗吸收塔模拟及内件优化设计[J].山东化工,2015,44(11):122-124,127.
[10]陈晓峰,张述伟,曲平.低温甲醇洗系统模拟软件界面开发[J].计算机与应用化学,2004,(4):547-551.
[11]顾卫忠.低温甲醇洗吸收流程的仿真研究[D].杭州:浙江大学,2006.
[12]何杰,沈益,李美玲,等.低温甲醇洗PSRK热力学方程改进与全流程模拟[J].化学工程,2017,45(3):69-74.
[13]谢东升.基于修正PSRK和RKSWS状态方程的低温甲醇洗吸收塔模拟研究[J].广东化工,2017,44(14):86-87,89.
[14]张正军.低温甲醇洗装置扩产改造总结[J].化肥工业,2011,38(2):48-52.
[15]崔静思.低温甲醇洗工艺节能改进探讨[J].神华科技,2015,13(1):93-96.
[16]Li Sun,Robin Smith.Rectisol wash process simulation and analysis[J].Journal of Cleaner Production,2013,39:321-328.
[2]赵鹏飞.低温甲醇洗技术及其在煤化工中的应用[J].石化技术,2017,24(5):4.
[3]石晓林,李东风.低温甲醇洗技术净化工艺及研究进展[J].煤炭与化工,2016,39(11):21-25.
[4]孙兰义.化工流程模拟实训——Aspen Plus教程[M].北京:化学工业出版社,2012.
[5]杨声.低温甲醇洗的模拟与热力学优化[D].大连:大连理工大学,2014.
[6]钱华光,张述伟,管凤宝,等.低温甲醇洗装置工艺模拟及改造研究[J].大氮肥,2012,35(4):222-224.
[7]Mathias P M,Copeman T W.Extension of the Peng-Robinson equation of state to complex mixtures:Evaluation of the various forms of the local composition concept[J].Fluid Phase Equilibria,1983,13(10):91-108.
[8]Itagaki H,Hagino S,Kato S,et al.PSRK groupcontribution equation of state:Comprehensive revision andextensionⅣ,including critical constants andα-functionparameters for 1 000 components[J].Fluid Phase Equilibria,2005,227(2):157-164.
[9]蒋燕,马炯.低温甲醇洗吸收塔模拟及内件优化设计[J].山东化工,2015,44(11):122-124,127.
[10]陈晓峰,张述伟,曲平.低温甲醇洗系统模拟软件界面开发[J].计算机与应用化学,2004,(4):547-551.
[11]顾卫忠.低温甲醇洗吸收流程的仿真研究[D].杭州:浙江大学,2006.
[12]何杰,沈益,李美玲,等.低温甲醇洗PSRK热力学方程改进与全流程模拟[J].化学工程,2017,45(3):69-74.
[13]谢东升.基于修正PSRK和RKSWS状态方程的低温甲醇洗吸收塔模拟研究[J].广东化工,2017,44(14):86-87,89.
[14]张正军.低温甲醇洗装置扩产改造总结[J].化肥工业,2011,38(2):48-52.
[15]崔静思.低温甲醇洗工艺节能改进探讨[J].神华科技,2015,13(1):93-96.
[16]Li Sun,Robin Smith.Rectisol wash process simulation and analysis[J].Journal of Cleaner Production,2013,39:321-328.