Hydrogenation method for pyrolysis gasoline

Abstract

The invention provides a hydrogenation method for pyrolysis gasoline, wherein the pyrolysis gasoline which is by-produced in the ethylene production process is preheated and then enters a fixed bed hydrogenation reactor, the reactor is filled with nickel-molybdenum-zinc series hydrogenation catalysts, and after hydrogenation, the material is sent to the second-stage hydrogenation reactor; the catalysts prepared by using the nickel-containing carrier having the specific crystalline form prepared by the hydrogenation method for the pyrolysis gasoline can greatly improve the utilization ratio ofactive metal and reduce the preparation difficulty of the catalyst, and a synergistic action of selected active components can be added to play a synergistic effect to obtain active, selective and stable first-stage hydrogenation catalyst for the pyrolysis gasoline.

Description

technical field [0001] The invention relates to a hydrogenation method for diolefinic unsaturated hydrocarbons, in particular to a selective hydrogenation process for middle and low distillate oils, and is especially suitable for the selective hydrogenation process of whole distillate and middle distillate pyrolysis gasoline. Background technique [0002] Many countries regard the output of ethylene as a symbol of the development level of the country's petrochemical industry. my country's ethylene production is increasing year by year, reaching 20 million tons in 2015. As an important by-product of ethylene cracking, pyrolysis gasoline accounts for about 50% to 80% of the ethylene production capacity. How to make good use of this part of by-products will have a major impact on improving the economic benefits of enterprises. At the same time, pyrolysis gasoline also contains a large amount of unsaturated hydrocarbons such as diolefins, alkenyl aromatics, indene, and impurit...

AI Technical Summary

Problems solved by technology

[0007] CN1218822A has reported a kind of Ni / Al 2 o 3 A selective hydrogenation catalyst suitable for pyrolysis gasoline fractions. The catalyst is prepared by loading nickel on an alumina carrier containing lithium or alkaline earth metals. This catalyst is not good in hydrogenation load and hydrogenation stability.

Therefore, there are the following problems in the impregnation process: (1) due to the constant water absorption of the carrier, the volume of the impregnating solution using the equal volume impregnation method is constant, and the high addition of active metal components will cause incomplete dissolution; (2) the preparation of the catalyst process It is necessary to impregnate the active component multiple times in the medium, twice, three times or even four times to impregnate a certain amount of active component on the carrier, which causes problems such as complicated preparation process, long preparation cycle, and loss of active component; (3 ) In the process of multiple impregnation, it is often necessary to add organic or inorganic dispersants to the impregnation solution to increase the dispersion of active metal components, but these will have the problem of removal during post-treatment

However, the active metal compound is directly mixed with aluminum hydroxide dry rubber powder or alumina powder by kneading method. This method has problems such as uneven mixing of crystal particles and deterioration of catalyst strength. At the same time, it is not easy to combine the components simply by kneading. form a specific skeleton structure

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