Isomerization method for light hydrocarbon

Abstract

The invention relates to a light hydrocarbon isomerization method. Isomerization reaction is performed for light hydrocarbon raw material in an isomerization reactor at the front part, gas-liquid separation is performed for the outlet stream of the reactor at the front part, the obtained liquid phase stream is separated in an isohexane removing tower, the overhead stream mainly comprising C5 cut fraction and dimethyl C6 alkane is mixed with the bottom stream mainly comprising C7 and cut fractions more than C7 so as to be used as isomate to enter into a gasoline stabilizer, the side stream mainly comprising C6 n-alkane and monomethyl C6 alkane is led into an isomerization reactor at the rear part; after the reaction stream of the isomerization reactor at the rear part is separated, the liquid phase stream all returns and is mixed with the liquid phase stream of a gas-liquid separator of the isomerization reactor at the front part so as to be used as the feeding of the isohexane removing tower. The method has higher n-alkane isomerization ratio and greatly improves the octane number of the light hydrocarbons raw material because the C6 n-alkane basically realizes the full isomerization.

Description

technical field [0001] The invention relates to a method for isomerizing light hydrocarbons, more specifically, a method for generating branched isoparaffins from straight-chain alkanes with smaller carbon atoms through hydroisomerization to increase the octane content of light hydrocarbon raw materials. alkane number method. Background technique [0002] During the primary processing and secondary processing of crude oil, light hydrocarbon fractions mainly composed of C5 and C6 will be produced, which can be used as blending components of gasoline, raw materials for ethylene cracking or hydrogen production by steam reforming of light hydrocarbons raw material. Since the light hydrocarbon does not contain olefins and aromatics, it is a better gasoline blending component, but the low octane number of the light hydrocarbon limits its blending ratio in gasoline. Light hydrocarbon isomerization technology is to convert normal paraffins in light hydrocarbons into isoparaffins, ...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that a part of the liquid phase stream of the gas-liquid separator of the rear isomerization reaction system is drawn out as an isomerization product. Since the isomerization reaction is controlled by thermodynamic equilibrium, a certain amount of Normal alkanes, which have a negative impact on increasing the octane number of the isomerization reaction product, and the accumulation of heavy components in the reaction system cannot be solved without this stream

Therefore, in fact, the light hydrocarbon isomerization method proposed by ZL03102218.9 only realizes partial recycling of normal alkanes, and it is not easy to obtain isomerized products with higher octane numbers

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