七芳工場之萃取蒸餾效能提昇與節能研究

A Study of The Enhancement of Efficiency of Extractive Distillation and Energy Saving in No.7 Aromatics Extraction Unit

柯經緯(Jing-Wei Ko) ； 孫祥耀(Hsiang-Yao Sun) ； 薛虹紅(Hong-Hong Hsueh) ； 施育婷(Yu-Ting Shih) ； 賴宗成(Zong-Cheng Lai) ； 莊秀淓(Shiou-Fang Chuang) ； 黃正彥(Zheng-Yan Huang) ； 陳松江(Sung-Jiang Chen) ； 李明禮(Ming-Li Li) ； 褚候順(Hau-Shun Chu) ； 宋文池(Wen-Chih Sung) ； 陳維德(Wei-De Chen)

《石油季刊》 53卷4期 (2017/12) Pp. 39-56

摘要

第七芳香烴工場的BTX 進料主要有四輕、新三輕製程產生的芳香烴進料油，七芳工場之萃取蒸餾塔(V-7001)使用對芳香烴具有親和力的高沸點溶劑(Sulfolane、3 Methyl Sulfolane)，降低芳香烴的活性係數，提昇非芳香烴的活性係數，蒸餾時塔頂萃餘油大多為非芳香烴，而塔底萃取油只含有溶劑及芳香烴；萃取油經溶劑回收塔(V-7002)將溶劑與芳香烴產品分離。 當貧溶劑中高碳數非芳香烴的含量多時，無法有效降低芳香烴的活性係數與提昇非芳香烴的活性係數，使萃取蒸餾塔之分離效率降低，造成能耗增加。七芳工場從102 年8 月開俥投產，103 年1 月起貧溶劑中高碳數非芳香烴的含量由10%逐漸累積至18%，使萃取蒸餾塔之分離效率降低。林園廠與煉研所共同討論移除貧溶劑中高碳數非芳香烴的之方法，並在實驗室進行實驗，確認可行後，林園廠技術組與煉研所共同規劃流程，104 年1月林園廠完成施工；104 年2 月開始進行貧溶劑中之提純作業，將高碳數非芳香烴移除，至105 年12 月止，貧溶劑中Sulfolane 與3 Methyl Sulfolane 之濃度由82%提昇至90%以上，最高可達98%。根據PI 取得之數據，貧溶劑提純前(103 年1 月~104 年1 月)，每公秉七芳進料流量之再沸器使用水蒸氣流量之平均為807.8 Kg;貧溶劑提純後(104 年2 月~104 年12 月)，每公秉七芳進料流量之再沸器使用水蒸氣流量之平均為685.4 Kg，減少15.2%，貧溶劑提純後(105年1 月~105 年12 月)，每公秉七芳進料流量之再沸器使用水蒸氣流量之平均為643.4 Kg，減少20.4%。根據會計帳，貧溶劑提純後(104 年2 月~104 年12 月)共降低公用成本1 億3 千5 百萬元，貧溶劑提純後(105 年1 月~105 年12 月)降低公用成本1 億1 千9 百萬元，兩年合計2 億5 千4 百萬元，其中林園廠技術組規劃流程，並負責管線、設備安裝，現場負責操作之事宜，林園廠貢獻度70%(17,780 萬元)，煉研所貢獻度30%(7,620 萬元)。

關鍵字

萃取 ； 蒸餾 ； 溶劑

並列摘要

The feedstocks of No.7 Aromatic Extraction Unit are aromatic oils coming from No.4 Naphtha Cracking Unit and New No.3 Naphtha Cracking Unit. The extractive distillation column utilizes high boiling point solvents (Sulfolane、3 methyl Sulfolane) that are capable of the affinity to aromatic hydrocarbons, which reduces the activity coefficient of aromatic hydrocarbons and enhances the activity coefficient of non-aromatic hydrocarbons. The raffinate from top of the column is non-aromatic hydrocarbons. The extract from bottom of the column is solvent and aromatic hydrocarbons. The extract is separated at the solvent recovery column (V-7002) to obtain the solvent at the bottom of the column and aromatic hydrocarbons at the top of the column. As the lean solvent contains too much non-aromatic hydrocarbons, it cannot reduce the activity coefficient of aromatic hydrocarbons and enhance the activity coefficient of nonaromatic hydrocarbons effectively, which causes the separation efficiency of the extractive distillation column to reduce and the energy consumption to increase. No.7 Aromatic Extraction Unit started up in Aug. 102. The content of heavier nonaromatic hydrocarbons is going from 10% to 18% gradually from Jan. 103. The separation efficiency of the extractive distillation column is reduced significantly. The staffs of Lin-yuan plant and RMRI discussed the way to remove the heavier nonaromatic hydrocarbons contained in lean solvent. After having performed the experiment in the laboratory, the way to remove the heavier non-aromatic hydrocarbons contained in lean solvent has to be verified. The staffs of Lin-yuan plant and RMRI planned the flow sheet of the removing of heavier non-aromatics contained in lean solvent together. The Lin-yuan plant completed the revamping work in Jan. 104. The removing operation of the heavier non-aromatic hydrocarbons contained in lean solvent started from Feb. 104. to Dec. 104. The content of sulfolane and 3 methyl Sulfolane contained in lean solvent is from 82% to 98% during the removing operat ion. The average amount of the total heating steam flow rate of reboiler per KL feedstock is 807.8 Kg before the purifying procedure of lean solvent (from Jan. 103 to Jan. 104). The average of the total heating steam flow rate of reboiler per KL feedstock is 685.4 Kg after the purifying procedure of lean solvent (from Feb. 104 to Dec. 104). The average of the total heating steam flow rate of reboiler per KL feedstock is 643.4 Kg after the purifying procedure of lean solvent (from Jan. 105 to Dec. 105) According to the account of Lin-yuan plant, the utilities cost reduces 254 million NT$ after the purifying procedure of lean solvent (from Feb. 104 to Dec. 105).

並列關鍵字

Extraction ； Distillation ； Solvent