Moving bed C3/C4 alkane dehydrogenation process

Abstract

The invention discloses a moving bed C3 / C4 alkane dehydrogenation process. A catalyst has a flowing direction (among reactors)opposite to that of a reactant flow. The method comprises the following steps: feeding a mixed hydrogen and C3 / C4 alkane fed material flow through a heat integration heat exchanger and a heating furnace, feeding the flow into a first-stage reactor, and feeding the flow through a second-stage reactor and a final-stage reactor in series in sequence to form a reaction material flow; and regenerating the catalyst by using a regenerator, feeding the catalyst into the final-stage reactor, and feeding the catalyst through the second-stage reactor and the final-stage reactor in series in sequence to form a catalyst flow, wherein a hydrogen permeable membrane separator is arranged at the outlet of each stage of the reactors. Compared with a conventional industrial propane dehydrogenation process, the process is capable of increasing the per-pass conversion rate of C3 / C4alkane, reducing reaction temperatures, improving selectivity, saving energy, reducing carbon accumulation on the catalyst, prolonging the service life of the catalyst and reducing investment of devices.

Description

technical field [0001] The invention relates to the field of C3 / C4 alkane dehydrogenation to olefins in petrochemical industry, and furthermore, relates to a countercurrent moving bed C3 / C4 alkane dehydrogenation process. Background technique [0002] Propylene is an important organic chemical raw material and an important petrochemical basic raw material second only to ethylene. It is widely used in the production of polypropylene, acrylonitrile, isopropanol, phenol and acetone, butanol and octanol, acrylic acid and its lipids And the system of propylene oxide and propylene glycol, epichlorohydrin and synthetic glycerol, etc. At present, petroleum-based propylene and coal-based propylene account for a relatively large proportion of propylene production. Propylene produced from oil-based olefins accounts for about 66% of propylene production, while coal-based olefins accounts for about 20%. Compared with the previous two processes, propane The propylene output of the dehydr...

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Problems solved by technology

[0017] The advantage of this way of conveying the reactant stream and the catalyst stream is that the pressure is easy to transport from high to low, and the disadvantage is that the reactor with a high-activity catalyst is the material that is easy to react, while the reactor with a low-activity catalyst is carried out. It is a material that is difficult to react. The active state of the catalyst in the reactor does not match the difficulty of the reaction. This arrangement will increase the feed temperature of the third-stage reactor, aggravate the carbon deposition of the catalyst and shorten the life of the catalyst.

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