煤焦油中分离精制2-甲基萘技术进展及工业化现状

Technical progress and industrialization status on the separation andpurification of 2-methylnaphthalene from coal tar

2-甲基萘是一种重要的有机化工原料,用途广泛,随着我国精细化工行业的迅速发展,从洗油中分离精制2-甲基萘受到重视。基于洗油加工,论述了从煤焦油中分离精制2-甲基萘的技术特点,介绍了国内外生产2-甲基萘的工业化现状及工艺,并对2-甲基萘分离精制技术研究、产业化发展方向进行了展望。洗油中多种组分相互间可形成多种共沸物和共熔物,很难利用单一的分离精制工艺方法从洗油中得到高纯度2-甲基萘。目前2-甲基萘的分离精制技术是精馏法、共沸精馏法、烷基化法、酸碱洗涤法、异构化法、溶剂重结晶法、溶剂萃取法、冷冻结晶法等单一分离方法的组合。洗涤精馏结晶法成熟可靠,是工业上使用最广泛的2-甲基萘生产技术,但酸碱洗涤存在环境污染、设备腐蚀等问题。洗涤和多级精馏相结合的方法工艺流程简单、生产效率高,但产品纯度有待提高。精馏和共沸精馏相结合的方法绿色环保、成本低,产品中吲哚含量低,是未来分离精制2-甲基萘的发展方向。化学反应和精馏结晶相结合分离精制2-甲基萘的收率高,产品纯度高,但化学反应所需的特殊反应器和催化剂增加了生产成本。国内生产2-甲基萘的企业与国外相比,在产品种类和纯度、能耗、环保等方面存在差距,绿色环保和高效节能是洗油加工企业未来的发展趋势。加强新技术、新工艺的开发,提高产品收率和纯度,解决2-甲基萘分离精制中的产业化、规模化的技术问题,是提高煤化工企业经济和社会效益的有效手段。开发洗油加工中2-甲基萘的绿色分离过程工艺,提高各种分离精制方法的耦合水平,既符合化工生产过程中“节能低碳”的环保要求,也是未来洗油深加工技术的发展方向。

2-Methylanaphthalene is an important organic chemical raw material with a wide application range.With the rapid development of fine chemical industry,separating 2-methyl naphthalene from washing oil has received attention.From the perspective of oil washing processing,the technical characteristics of various separation and purification 2-methylnaphthalene techniques from wash oil were discussed.The industrial status and technological characteristics of 2-methylnaphthalene production at home and abroad were introduced,and the development direction of 2-methylnaphthalene separation and purification technologies and industrialization were prospected.Wash oil′s components form many azeotrope and eutectic mixture.It is difficult to separate and refine 2-methylnaphthalene products with high purity from wash oil by a single process of separating and refining method.At present,the separation and purification techniques of 2-methylnaphthalene are the combination of distillation,azeotropic distillation,alkylation,acid-alkaline washing,isomerization,solvent recrystallization,solvent extraction,freezing crystallization and so on.The washing-distillation-crystallization method is mature and reliable,which is the most widely used 2-methylnaphthalene production technology in industry.However,acid and alkali washing has environmental pollution,equipment corrosion and other problems.The process of washing and multistage distillation is simple and the production efficiency is high,but the purity of the product needs to be improved.The combination of distillation and azeotropic distillation is green,low cost and low indole content.It is the development direction of separating and refining 2-methyl naphthalene in the future.The method of combining chemical reaction with distillation crystallization is high in yield and purity,but the special reactor and catalyst needed for chemical reaction increase the production cost.Compared with similar enterprises abroad,domestic enterprises producing 2-methylnaphthalene have gaps in product type and purity,energy consumption,environmental protection and so on.Green environmental protection and high efficiency energy saving are the future development trends of oil washing processing enterprises.It is an effective means to improve the economic and social benefits of coal chemical enterprises to strengthen the development of new technologies and new processes,improve the product yield and purity,and solve the technical problems of industrialization and scale in 2-methyl naphthalene separation and refining.The development of the green separation process of 2-methyl naphthalene in oil washing processing to improve the coupling level of various separation and refining methods will not only meet the environmental protection requirements of"energy saving and low carbon"in the chemical production process,but also is the development direction of the future oil washing deep processing technology.