Abstract：The study used the column grand composite curve (CGCC) method to simultaneously optimize the feed location and feed conditions for a distillation column to reduce the total utility costs. The CGCC method based on the near-minimum thermodynamic condition (PNMTC) can be decomposed into two theoretical curves for the overall rectifying and overall stripping curves. The intersection point O of the two theoretical curves is not only the ideal feed point, but also the partitioning point for the amount of feed preheating. The total cost of the cold and hot utilities is used as the objective function to optimize the feed preheating and to identify the intersection point location O. The optimal feed location in the distillation column is then found using the enthalpy difference, ΔHn, def, between the intersection point and the actual feed point. The feed location and the feed conditions are then optimized using the CGCC curves. A benzene and toluene column was used to evaluate the accuracy of this graphic method. The maximum savings for the cold and hot utilities is about 1.24 RMB/h. The feed preheating is 1.98 MW and the enthalpy difference, ΔHn, def, is 0.038 MW. The optimal feed location is the 21th stage. The CGCC results compare well with Aspen Plus results with differences only 1%-3%.
刘雪刚, 张冰剑, 陈清林. 基于分馏塔总组合曲线进料位置与进料状态的同步优化[J]. 清华大学学报（自然科学版）, 2016, 56(7): 700-706.
LIU Xuegang, ZHANG Bingjian, CHEN Qinglin. Simultaneous optimization of the feed location and thermodynamic feed conditions for a distillation column based on column grand composite curves. Journal of Tsinghua University(Science and Technology), 2016, 56(7): 700-706.
 Shahandeh H, Ivakpour J, Kasiri N. Internal and external HIDiCs (heat-integrated distillation columns) optimization by genetic algorithm[J]. Energy, 2014, 64(11):875-886.
 Dhole V, Linnhoff B. Distillation column targets[J]. Computers and Chemical Engineering, 1993, 17(56):549-560.
 Flower J R, Jackson M A. Energy requirements in the separation pf mixtures by distillation[J]. Transactions Institution of Chemical Engineering, 1964, 42(2):249-258.
 Fonyo Z. Thermodynamic analysis of rectification. I. Reversible model of rectification[J]. International Chemical Engineering, 1974, 14(5):203-210.
 李会泉, 祝刚, 王世广, 等. 复杂精馏塔的用能分析法[J]. 高校化学工程学报, 1998, 12(2):146-151.LI Huiquan, ZHU Gang, WANG Shiguang, et al. Analysis of energy utilization of complex column[J]. Journal of Chemical Engineering of Chinese Universities, 1998, 12(2):146-151. (in Chinese)
 吴升元, 魏志强, 张冰剑, 等. 基于CGCC的分馏塔进料位置[J]. 化工进展, 2011, 30(10):111-117.WU Shengyuan, WEI Zhiqiang, ZHANG Bingjian, et al. Study on the feed location of distillation column based on CGCC[J]. Chemical Industry and Engineering Process, 2011, 30(10):111-117. (in Chinese)
 Bandyopadhyay S, Malik R, Shenoy U. Invariant rectifying-stripping curves for targeting minimum energy and feed location in distillation[J]. Computers and Chemical Engineering, 1999, 23(13):1109-1124.
 Bandyopadhyay S. Effect of feed on optimal thermodynamic performance of a distillation column[J]. Chemical Engineering Journal, 2002, 88(10):175-186.
 Bandyopadhyay S. Thermal integration of a distillation column through side-exchangers[J]. Chemical Engineering Research and Design, 2007, 85(8):156-166.
 CHEN Ting, ZHANG Bingjian, CHEN Qinglin. Heat integration of fractionating systems in para-xylene plants based on column optimization[J]. Energy, 2014, 72(16):311-321.
 徐忠, 陆恩锡. 蒸馏过程进料位置优化[J]. 化学工程, 2008, 36(7):74-78.XU Zhong, LU Enxi. Optimization of feed tray location in distillation[J]. Chemical Engineering, 2008, 36(7):74-78. (in Chinese)
 陆恩锡, 张慧娟. 化工过程模拟——原理与应用[M]. 广州:化学工业出版社, 2005.LU Enxi, ZHANG Huijuan. Chemical process simulation-Principles and applications[M]. Guangzhou:Chemical Industry Press, 2005. (in Chinese)
 Bandyopadhyay S, Malik R, Shenoy U. Feed preconditioning targets for distillation through invariant rectifying-stripping curves[J]. Industrial and Engineering Chemistry Research, 2003, 42(7):6851-6861.
 Pinto F, Zemp R, Jobson M. et al. Thermodynamic optimisation of distillation columns[J]. Chemical Engineering Science, 2011, 66(14):2920-2934.
 Bandyopadhyay S, Malik R, Shenoy U. Temperature-enthalpy curve for energy targeting of distillation columns[J]. Computer Chemical Engineering, 1998, 22(3):1733-1744.
 WEI Zhiqiang, WU Shengyuan, ZHANG Bingjian, et al. Modified approach for generating column grand composite curves[J]. Chemical Engineering Technology, 2012, 35(9):1817-1824.
 Linnhoff B, Hindmarsh E. The pinch design method for heat exchanger networks[J]. Chemical, Engineering, Science, 1983, 38(6):745.
 陆恩锡, 罗明辉. 蒸馏过程进料状态优化[J]. 化学工程, 2008, 36(6):75-78.LU Enxi, LUO Minghui. Optimization of feed state in distillation[J]. Chemical Engineering, 2008, 36(6):75-78. (in Chinese)