A kind of recovery method and application of waste molecular sieve catalyst fine powder of dmto unit

Abstract

The invention discloses a method for recovering the fine powder of the waste molecular sieve catalyst of the DMTO device, which comprises the following methods: (1) drying the fine powder of the waste molecular sieve catalyst of the DMTO device, roasting and cooling; (2) drying the waste molecular sieve catalyst powder of the DMTO device after roasting Put the fine powder of the catalyst in an appropriate amount of deionized water to disperse evenly, add inorganic acid to adjust the pH to 2~5, and age for 3~6h; Crystallization under self-pressure conditions for 12-48 hours, filtering, drying, and roasting to obtain molecular sieve powder. The invention has simple process steps, strong operability, low recovery cost, and can realize the reuse of waste agent, and the obtained molecular sieve raw powder can be directly applied to the by-product C of DMTO 4 / C 5 + Cracking of olefins, thereby increasing the production of ethylene and propylene in the plant.

Description

technical field [0001] The invention relates to the technical field of methanol-to-olefins, in particular to a method for recovering fine powder of spent molecular sieve catalysts in a DMTO unit and its application. Background technique [0002] Ethylene and propylene are the cornerstones of the huge petrochemical industry, and the vast majority of petrochemical products are derived from ethylene and propylene. In view of my country's national conditions of "rich coal, poor oil and little gas", methanol-to-olefin (MTO) technology, as an emerging high-end core technology in the field of energy and chemical industry in the world, can give full play to domestic resource advantages and broaden the source of olefin raw materials, so that China can successfully get rid of olefin products. The heavy dependence on oil resources has effectively reduced the dependence on foreign oil. After decades of hard work, my country has developed a complete set of methanol-to-olefins technology ...

AI Technical Summary

Problems solved by technology

This method has the following defects: (1) the waste molecular sieve fine powder is directly roasted to remove carbon deposits, which is very easy to sinter into agglomerates, which not only cannot completely remove carbon deposits, but also is unfavorable for subsequent dispersion; (2) is washed with water and then dried. It will agglomerate when dry; (3) in the methanol-to-olefins reaction, the SAPO-type molecular sieve catalyst will cause part of the crystal structure to be destroyed (collapsed) due to continuous complex mechanical, thermal and chemical actions, so this method cannot really Realize the complete recovery of the catalyst performance. After the SAPO-34 molecular sieve catalyst is remade as a raw material, the selectivity and activity of the molecular sieve will be greatly affected, and the strength and catalytic performance of the fresh catalyst still cannot be achieved; (4) Silicon source needs to be added , aluminum source, phosphorus source and other raw materials, resulting in high recycling costs; (5) direct roasting when removing the template agent, the carbon deposit formed before the template agent is burned in time, resulting in yellowing or even blackening of the catalyst, affecting the selectivity and active