A modified molecular sieve catalyst for ethanol dehydration to ethylene and its application

Abstract

The invention discloses a modified molecular sieve catalyst for ethanol dehydration to ethylene. The catalyst uses HZSM-5 molecular sieve powder and macroporous pseudo-boehmite powder as raw materials to prepare an unmodified strip-shaped molecular sieve catalyst, and then sequentially uses Na 2 CO 3 The aqueous solution and the citric acid aqueous solution are subjected to alkali modification and acid modification, and are prepared by drying and roasting; the invention also discloses the application of a modified molecular sieve catalyst for ethanol dehydration to ethylene. In the preparation and modification process of the catalyst of the present invention, no stirring process is required, the preparation process is simplified, and at the same time, the amount of weak acid on the surface of the catalyst is greatly increased, and the amount of medium-strong acid is reduced, thereby improving the catalytic performance of the modified molecular sieve catalyst for the reaction of ethanol dehydration to ethylene , and improve the conversion rate of raw material ethanol and the selectivity of product ethylene, and prolong the service life of the modified molecular sieve catalyst; the application of the modified molecular sieve catalyst of the present invention in ethanol dehydration to ethylene is simple and suitable for popularization.

Description

technical field [0001] The invention belongs to the technical field of catalyst preparation, and in particular relates to a modified molecular sieve catalyst for ethanol dehydration to ethylene and an application thereof. Background technique [0002] Ethylene is one of the most basic raw materials in the organic chemical industry. It is mainly used in synthetic resins, rubber, fibers, coatings, adhesives, surfactants and other polymer materials. At the same time, the modern ethylene industry produces ethylene and by-products such as propylene, butadiene, benzene, xylene, etc., which are also important raw materials for the manufacture of related synthetic materials. At present, the main raw materials for industrial production of ethylene come from two ways: one is light hydrocarbons from natural gas processing plants: such as ethane, propane, butane, etc.; the other is processed products from refineries: such as refinery gas, gasoline, diesel oil, etc.; The raw materials o...

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Problems solved by technology

[0005] At present, there are various shortcomings in the process of acid-base modification of HZSM-5 molecular sieve: the main reason is that the modification process is relatively complicated. Generally, the acid-base modification of molecular sieve powder is carried out first, because the raw material exists in powder form, so in order to To ensure the uniformity of modification, it is necessary to use mechanical stirring, which leads to high energy consumption in the modification process. After modification, drying, roasting and other processes are required to form modified molecular sieve powder, and then use the modified molecular sieve powder Molecular sieve powder as raw material and macroporous pseudo-boehmite powder are bonded, extruded, dried, and roasted to prepare the acid-base modified molecular sieve catalyst

However, the molecular sieve catalyst uses relatively expensive organic bases such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, etc. in the modification, resulting in higher preparation costs for the modified catalyst

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