A Two-stage Condensation and Separation Method and Separation System for Oil and Gas at the Top of a Crude Atmospheric Distillation Tower

Abstract

The invention discloses a crude-oil normal-pressure distillation tower top oil gas two-stage condensation separation method. According to the crude-oil normal-pressure distillation tower top oil gas two-stage condensation separation method, tower top oil gas obtained via distillation of crude oil in a normal-pressure distillation tower is delivered through a first heat exchanger and a second heatexchanger which are connected via shell-side series connection for heat exchange and liquidation, and is collected in a first backflow oil tank so as to obtain a reformed material, wherein the oil gastemperature at an output end of the first heat exchanger is maintained to be 90 to 95 DEG C, and the oil gas temperature at an input end of the first backflow oil tank is maintained to be 85 to 90 DEG C; uncondensated oil gas in the first backflow oil tank is delivered through an air cooler and a third heat exchanger which are connected in series for heat exchanging and liquidation, and is collected in a second backflow oil tank so as to obtain an ethene material, wherein the oil gas temperature at an input end of the second backflow oil tank is maintained to be 30 to 40 DEG C; uncondensatedoil gas in the second backflow oil tank is subjected to compression using a compressor, and is delivered into a catalytic device gas enrichment system for recycling. The invention also discloses a separation system of the crude-oil normal-pressure distillation tower top oil gas two-stage condensation separation method. The crude-oil normal-pressure distillation tower top oil gas two-stage condensation separation method is low in energy consumption and investment cost, process flow is simple, and high efficiency and continuous separation of the reformed material and the ethene material are realized.

Description

technical field [0001] The invention belongs to petroleum refining technology, in particular to a two-stage condensation and separation method and separation system for oil and gas at the top of a crude oil atmospheric distillation tower. Background technique: [0002] During the distillation process of crude oil, due to the difference in volatilization ability of each component, the lighter components form high-temperature oil and gas at the top of the atmospheric distillation tower, which are cooled and separated into products such as naphtha and non-condensable gas. Naphtha is directly used as the deployment of vehicle fuel gasoline, and there are problems such as unqualified saturated vapor pressure and low octane number. In the application of oil refining industry, naphtha is generally used as raw material for ethylene cracking (hereinafter referred to as ethylene material) and catalytic reforming Raw material (hereinafter referred to as reformate), etc. [0003] Gener...

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Problems solved by technology

[0005] The constant top oil (i.e. naphtha) obtained by the above process cannot be directly used as ethylene feedstock or reformate due to its wide fraction. It needs to be further separated through a rectification tower to be cut into ethylene feedstock and aromatic potential with higher alkane content. For higher reformate, additional heat needs to be provided for rectification during the rectification process, resulting in problems such as large equipment investment, high energy consumption, and complicated process

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