Method for preparing butadiene with butylene oxo-dehydrogenation of axially-located bed

Abstract

The invention relates to a method of preparing butadience with a butylene oxydehydrogenation device in a fixed bed, which belongs to the chemical technical field. The butylene, air and water vapor give an oxydehydrogenation reaction in an axial fixed bed reactor and generate the butadience. The axial fixed bed reactor has two segments. Process equipment consists of a first segment of axial fixed bed reactor, an inter -segment heat exchanger, a second segment of axial fixed bed reactor, a waste heat boiler and a back heat exchanger in turn. The reactor is filled with iron-based catalyst. The ingredient of the water vapor of the first segment of reactor acts with the first segment via the inter-segment heat exchanger to generate gas in addition to exchanging heat and raising temperature and then is mixed with the ingredient butylene and the air of the first segment to achieve the inlet temperature of the first segment of reactor. The ingredient of the first segment enters to the first segment of reactor to react. After heat exchange and temperature reduction through the inter-segment heat exchanger, the gas generated in the first segment is mixed with the feed butylene of the second segment and the air to achieve the inlet temperature of the second segment of reactor and reacts in the second segment of reactor. The invention has the advantages of high yield coefficient, high selectivity and steam of low unit consumption. Heat energy can be used reasonably.

Description

Technical field [0001] The invention relates to a method for preparing butadiene by oxidative dehydrogenation of butene in an axial fixed bed, and belongs to the technical field of chemical industry. Background technique [0002] Butadiene is an important petrochemical product and the main raw material for the production of synthetic rubber. It is also widely used in the synthesis of engineering plastics and organic chemical products. Oxidative dehydrogenation of butene is an important method for producing butadiene. In the oxidative dehydrogenation of butene, two hydrogen and oxygen in the butene molecule combine to form water, so the reaction is irreversible and the process conditions are relatively mild. , There is a higher single-pass conversion rate and selectivity. The target product of butene oxidative dehydrogenation is butadiene, and the side reaction is the deep oxidation reaction of butene and butadiene, which mainly generates carbon monoxide, carbon dioxide and a smal...

AI Technical Summary

Problems solved by technology

As far as the bed type is concerned, fluidized beds were all used in my country in the early days. The disadvantages are that the catalyst is easy to be crushed and lost under the fluidized working state, and the catalyst consumption is large. The catalyst powder is easy to cause blockage of the rear system, and the unit consumption of steam is 7 More than tons

The early fixed bed was a radial bed. Although the problem of catalyst loss was solved, the cross-sectional area of ​​the bed layer changed with the size of the radius, which resulted in a high linear velocity in the reaction section, and poor conversion of butene and selectivity of butadiene. Ideal, the unit steam consumption is more than 8 tons

Among the existing technologies, the main disadvantage is that the yield of butadiene is low, only about 60%, which makes the production cost too high and cannot be compared with the method of cracking ethylene to produce butadiene, such as: American Petro-Tex iron-based catalyst Fixed bed, butadiene yield 60%, steam unit consumption 8.8 tons

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