化工进展 ›› 2021, Vol. 40 ›› Issue (7): 3626-3631.DOI: 10.16085/j.issn.1000-6613.2020-1598

• 化工过程与装备 • 上一篇    下一篇

煤制乙二醇装置联产碳酸二甲酯精馏工艺优化

孔会娜1(), 郑卫2, 曹海龙3(), 黄贵明3   

  1. 1.安阳化学工业集团有限责任公司,河南 安阳 455133
    2.安徽佑顺新材料有限公司,安徽 合肥 231500
    3.天津市新天进科技开发有限公司,天津 300193
  • 收稿日期:2020-08-11 修回日期:2020-09-19 出版日期:2021-07-06 发布日期:2021-07-19
  • 通讯作者: 曹海龙
  • 作者简介:孔会娜(1986—),女,工程师,研究方向为煤制乙二醇。E-mail:huina-py@163.com

Process optimization of dimethyl carbonate rectifying in coal-to-ethylene glycol plant

KONG Huina1(), ZHEGN Wei2, CAO Hailong3(), HUANG Guiming3   

  1. 1.Anyang Chemical Industry Limited Liability Company, Anyang 455133, Henan, China
    2.Anhui Youshun New Material Company Limited, Heifei 231500, Anhui, China
    3.NewTianjin Technology & Development Company Limited, Tianjin 300193, China
  • Received:2020-08-11 Revised:2020-09-19 Online:2021-07-06 Published:2021-07-19
  • Contact: CAO Hailong

摘要:

在煤制乙二醇的生产过程中,会副产碳酸二甲酯(DMC)、甲酸甲酯、甲缩醛等,目前煤制乙二醇联产残液大都未进行有效分离和纯化,只能作为低纯度碳酸二甲酯或廉价杂醇处理,这样不仅造成甲醇损耗,而且降低了装置应有的经济性,因此经济合理地回收碳酸二甲酯具有重要的意义。由于甲醇与DMC形成二元共沸物,常规精馏方法无法将二者彻底分离。本文总结了各种DMC-甲醇分离方法,并优选采用变压精馏技术进行甲醇与DMC分离。利用煤制乙二醇中富含碳酸二甲酯以及甲醇、甲酸甲酯等杂质的副产残液为原料,提出3种改进工艺,获得99.9%以上高纯度DMC产品。计算结果表明,3种工艺方法分别适用于含量低于高压共沸组成、高于常压共沸组成、90%以上浓度DMC物料的分离,实现以更低能耗、更优化流程获得高纯度DMC产品。

关键词: 碳酸二甲酯, 甲醇, 精馏, 隔板塔, 热集成

Abstract:

Dimethyl carbonate (DMC), methyl formate and methylal etc. are co-products which are not well separated and discharged as waste materials in many coal-to-ethylene glycol plant. As DMC is a valuable and useful raw material in many fields, proper process is needed for DMC rectifying because DMC and methanol forms stable azeotrope and they cannot be completely separated by conventional distillation methods. Pressure swing distillation is chosen after comparing methods of DMC-methanol separation. Three improved process schemes are discussed and designed to be used in the recovery and purification of dimethyl carbonate from the co-product residual liquid, which contain methanol, dimethyl carbonate and methyl formate etc. in coal-to-ethylene glycol plant, to obtain high purity (over 99.9%) DMC product. Those three process schemes are suitable for feeding DMC composition lower than high pressure azeotropic composition, higher than normal pressure azeotropic composition and more than 90% DMC content, respectively, in which the lower energy consumption and high DMC purity can be achieved.

Key words: dimethyl carbonate, methanol, rectifying, divided wall column, heat integration

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