Catalyst for preparing ethylene by ethanol dehydration and preparation method thereof

Abstract

The invention discloses a catalyst for preparing ethylene by ethanol dehydration and a preparation method thereof, belonging to the technical filed of biomass power source and catalyst preparation. The catalyst is SAPO-34 molecular sieve modified by metal Mn ions, namely Mn / SAPO-34; and the catalyst is prepared by using the Morpholine as template agent and then introducing the modified metal ions before the molecular sieve is crystallized by the direct synthesis method. The invention overcomes and solves the problems of high cost and shortage of petroleum fuel, so that the process energy consumption is reduced, and the problem that zymotic ethanol of biomass is low in concentration and difficult in post application is solved; the ethanol is high in transformation rate, high in selectivity and purity of ethylene, good in catalytic activity, uneasy in carbon accumulation and long in operating period; the obtained molecular sieve is big grain single crystals which can be directly used in the fluidized bed and have good wearing resistance and reduced pelleting step; the modified metal ions are introduced before the molecular sieve is crystallized by the direct synthesis method so that the activity stability is good and the modified ions are not easy to run off during the reaction process.

Description

technical field [0001] The invention belongs to the technical field of biomass energy and catalyst preparation, and in particular relates to a catalyst for ethanol dehydration to ethylene and a preparation method thereof. Background technique [0002] Ethylene is an important basic organic chemical raw material and the cornerstone of the chemical industry. About 75% of chemical products use ethylene as raw material, which is widely used in many important organic chemicals such as polyethylene, ethylene oxide / ethylene glycol, dichloroethane, styrene, ethanol, vinyl acetate, propionaldehyde, etc. Production of products and polymers. The scale and level of the ethylene industry has become an important symbol reflecting the development level of a country's chemical industry. my country's ethylene production has increased rapidly, but it is still far from meeting consumption needs. For example, in 2005, my country's ethylene production was 7.55 million tons, while consumption r...

AI Technical Summary

Problems solved by technology

[0008] However, the direct use of SAPO-34 as a catalyst also has disadvantages: firstly, SAPO-34 has poor stability and is easy to deactivate, so metal ions need to be introduced to modify its acidity and pore structure to increase its stability.

If the synthesized molecular sieve is modified by impregnation by introducing metal ions, the activity of the metal ions may be lost due to the violent collision of the fluidized reaction particles in the fluidized bed.

Secondly, the synthesis of SAPO-34 usually uses tetraethylammonium hydroxide (TEAOH) or triethylamine (TEA) as a template, and the particle size is small (1-5μm), which cannot be directly used in an industrial fluidized bed, but only Granules suitable for fluidization can be obtained by adding binders or granulating by spraying and other methods, but the particles obtained by these methods have poor abrasion resistance and also increase the complexity of the entire process