Method and device for removing indole from beta-methylnaphthalene

Abstract

Relating to the field of chemical industry, the invention discloses a method and a device for removing indole from beta-methylnaphthalene. Structurally, the device comprises a distillation kettle and azeotropic distillation tower. An overflow recovery baffle is disposed at a tower top recovery outlet of the azeotropic distillation tower. A tower top recovery pipeline is connected to a cooler, a separation tank A and a separation tank B in order. The method includes: adding a mixture of the raw material beta-methylnaphthalene and an azeotropic agent into the distillation kettle, controlling the temperature of the kettle bottom at 145-147DEG C; maintaining the azeotropic distillation tower at a pressure of -70-90kpa and the tower top at a temperature of 140-142DEG C; carrying out intermittent azeotropic distillation separation, subjecting the evaporated liquid to cooling by the tower top cooler and internal reflux; and subjecting the azeotropic distillation tower top recovered liquid to cooling by the cooler, then leaving the liquid to flow into the separation tank A and the separation tank B in order, performing standing layering, and recovering the product. By means of the method and the device, after distillation separation, the content of the raw material beta-methylnaphthalene can be increased to over 98%, and the indole content decreased to an undetectable degree. The device and the method provided in the invention are simple and are easy to operate.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a method and a device for removing indole from beta-methylnaphthalene. Background technique [0002] At present, in the fields of petroleum and chemical industry, the method of separating and purifying compounds by means of azeotropic distillation has been widely used. Azeotropic distillation is a method of azeotropic distillation using an entrainer that can form an azeotropic mixture with low boiling point substances and high boiling point substances. [0003] The main viewpoints on the technical development of azeotropic distillation can be roughly divided into separation ability, controllability, reflux ratio reduction, and post-treatment of recovered distillate. Generally speaking, the higher the reflux ratio, the better the operation stability, and when the reflux ratio is decreased, the operation stability is generally worse. Furthermore, when the reflux ratio is reduced ...

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Problems solved by technology

However, waste acid and alkali are produced in the production process, which does not conform to the concept of environmental management in the 12th Five-Year Plan

[0007] In the patent "A method for refining β-methylnaphthalene from coal tar crude methylnaphthalene" (application number 200610134603.6), the azeotropic agent is selected as ethylene glycol, and the raw material is crude β-methylnaphthalene in coal tar. After the quinoline is eluted with acid, it is azeotroped with the entrainer, and the mixture of β-methylnaphthalene and entrainer is extracted, and the static layer is separated, and then the static layered liquid is rectified to obtain β-methylnaphthalene with a purity of about 95%. Methylnaphthalene, β-methylnaphthalene of this kind of purity, due to the low purity of the product, can only be used by domestic manufacturers and cannot be exported

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