Method and device for improving selectivity of low-carbon olefin preparation using oxygen-containing compound converting

Abstract

The invention belongs to the technical field of low-carbon olefin preparation, and discloses a method for improving the selectivity of low-carbon olefin preparation using oxygen-containing compound converting. The method comprises the following steps: feeding a regenerated catalyst from a regenerator into a pre-hydrocarbon pooling facility, making the regenerated catalyst contact an activation medium, carrying out a pre-hydrocarbon pooling reaction to form a hydrocarbon pool active species, feeding the pre-hydrocarbon pooling regenerated catalyst leaving the pre-hydrocarbon pooling facility into a conversion reactor, and recycling. According to the invention, the pre-hydrocarbon pooling facility is arranged, and the regeneration catalyst is subjected to pre-hydrocarbon pooling treatment, so that the regenerated catalyst forms the hydrocarbon pool active species and the carbon deposit before entering the conversion reactor, and the hydrocarbon pool active species distribution and the carbon deposit distribution of the catalyst in the conversion reactor are improved so as to shorten or eliminate the induction period of the conversion reaction and improve the catalytic activity and the selectivity of the reaction for preparing the low-carbon olefin from the oxygen-containing compound serving as the regenerant.

Description

technical field [0001] The invention relates to a method and a device for improving the selectivity of oxygen-containing compounds to produce low-carbon olefins. Background technique [0002] Light olefins, defined here as ethylene and propylene, are two important basic organic chemical raw materials. With the sustained and rapid economic development, the consumption of chemicals produced with ethylene and propylene as basic raw materials is increasing day by day, and the demand for chemicals produced from ethylene and propylene remains high. Ethylene and propylene are traditionally produced mainly through petroleum routes, but due to the limited supply and high price of petroleum resources, the cost of producing ethylene and propylene from petroleum resources continues to increase. With the shortage of petroleum resources, it is of great significance to use non-petroleum raw materials to produce methanol, and then to convert methanol to light olefins such as ethylene and p...

AI Technical Summary

Problems solved by technology

[0017] In summary, the "hydrocarbon pool" active species in industrially applied circulating fluidized bed reactors is dynamic and changing (its type and quantity are changing with reaction conditions (mainly reaction temperature)), so The catalyst bed not only has the problem of carbon deposit distribution, but also has the problem of uneven distribution of active species in the "hydrocarbon pool", which will inevitably affect the catalytic activity and selectivity of the reaction of methanol to light olefins

In fact, this is the main reason for the low yield of low-carbon olefins in the MTO unit

But for a long time, the above-mentioned problems have not been discovered by people, and no one has carried out special research and reports so far.

[0019] At the same time, the high-temperature regenerated catalyst directly enters the conversion reactor, and there is a temperature difference of hundreds of degrees (usually 150-300°C) with the catalyst in the conversion reactor, which will cause local overheating of the catalyst bed (the high-temperature regenerated agent itself and its surroundings), This leads to many side reactions in the conversion reaction process, a large amount of coke, and poor selectivity of low-carbon olefins

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