Fines co-feed for maintaining efficient reactor hydrodynamics

Abstract

This invention provides processes for maintaining a desired particle size distribution in an oxygenate to olefin reaction system. In one embodiment, the invention comprises replacing lost catalyst fines with less active co-catalyst particles. By adding less active co-catalyst particles to the reaction system, desirable fluidization characteristics and hydrodynamics can be maintained without affecting the overall (or primary catalyst) performance and product selectivities. The invention is also directed to a population of catalyst particles having a desirable particle size distribution well-suited for realizing ideal fluidization and hydrodynamic characteristics.

Description

field of invention [0001] The present invention relates to methods and systems for maintaining desired particle size characteristics within a reaction system. In particular, the present invention relates to the selective addition of cocatalyst particles, preferably oxygenates, to an olefin reaction system to maintain a desired particle size distribution within the system. Background of the invention [0002] Light olefins, defined here as ethylene and propylene, serve as feedstocks for the production of many chemicals. Olefins are conventionally produced by petroleum cracking. The cost of producing olefins from petroleum resources is steadily increasing due to limited supply and / or high cost of petroleum resources. [0003] Oxygenates, such as alcohols, especially methanol, dimethyl ether and ethanol, are alternative feedstocks for the production of light olefins. Alcohols can be produced by fermentation, or from synthesis gas derived from natural gas, petroleum liquids, ...

AI Technical Summary

Problems solved by technology

First, in large particle-rich reaction systems, circulating fluidized beds do not operate well especially in terms of catalyst circulation in standpipes, and in terms of gas distribution within the fluidized bed

Second, large particles that are selectively retained in the reaction system tend to lose their effectiveness, such as activity and selectivity, over time

However, this technique of removing undesired sized catalyst particles is inefficient because most of the desired sized catalyst particles are removed from the reaction system along with the undesired sized catalyst particles

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