Process for extracting C4-C6 normal paraffins and coproducing isopentane and heterogeneous hexane cooperatively produced from light naphtha

Abstract

The invention relates to a chemical separation process and in particular relates to a process for extracting C4-C6 normal paraffins and coproducing isopentane and heterogeneous hexane from light naphtha. A multi-tower variable pressure adsorption and distillation separation coupling process is adopted by the invention. The process comprises the following steps of: introducing mixed gaseous C4-C6 normal paraffins and isohydrocarbons serving as raw materials into an adsorption tower for adsorption and separation; desorbing a bed by taking gaseous C7-C9 normal paraffins as a desorption reagent after the adsorption ends; introducing the desorbed material into a rectifying tower to separate out the product C4-C6 normal paraffins and the desorption reagent C7-C9 normal paraffins; recycling the desorption reagent; then regenerating the adsorption tower which absorbs the C7-C9 normal paraffins by using the un-adsorbed C4-C6 isohydrocarbons; and rectifying and separating the regenerated material twice to obtain high-purity desorption reagent C7-C9 normal paraffins, high-purity isopentane and high-purity heterogeneous hexane. By adopting the process disclosed by the invention, normal paraffins and isohydrocarbons can be effectively separated; the adsorbent is easy to regenerate; the process flow is simple and economic benefit is high; and the energy consumption in the process disclosed by the invention is greatly reduced in comparison with the energy consumption in other desorption processes.

Description

Technical field: [0001] The invention relates to a chemical separation process, in particular to a process for extracting C4-C6 normal alkanes in light naphtha and co-producing isopentane and isohexane. Background technique: [0002] Light naphtha is one of the products of hydrocracking in the aromatics complex. Since most hydrogen production units use natural gas to produce hydrogen, light naphtha is mainly used as raw material for cracking ethylene production and gasoline blending material. Because the isoparaffins in the naphtha are too high, it is not suitable as a raw material for steam cracking to produce ethylene; as a gasoline blending material, because of its high content of n-paraffins, it affects the octane number of oil products. Therefore, the rational separation of n-isoparaffins in light naphtha is of great significance for improving the comprehensive utilization value of light naphtha, integrating optimized light naphtha resources, and increasing the economic...

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Problems solved by technology

[0006] CN101148390A and CN101134703A are all inventions of this laboratory. Since the use of inert gas desorption requires subsequent condensation temperature to be below zero, high condensation pressure is required, and energy consumption and equipment investment are relatively large

However, the combined desorption process using high-carbon C4-C6 normal alkanes in the gas phase as a desorbent and isoparaffins as a regenerating agent has not been reported, and the process can co-produce high-purity isopentane and isohexane as required, reducing energy consumption. greatly reduced, so on the basis of laboratory research, the invention of the process

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