Gasoline fraction desulfurization method, method for producing low-sulfur gasoline and reaction system

Abstract

The invention relates to a gasoline fraction desulfurization method, a method for producing low-sulfur gasoline and a reaction system. According to the method, a gasoline fraction enters a first reactor, and contacts a first hydrodesulfurization catalyst in the presence of hydrogen to carry out a first hydrodesulfurization reaction; a product obtained after the reaction enters a steam stripping tower, hydrogen-rich gas containing hydrogen sulfide and an intermediate gasoline fraction are obtained at the top of the steam stripping tower, a descending tower bottom material enters a second reactor and contacts a second desulfurization catalyst to be subjected to a secondary desulfurization reaction, a reaction product returns to the bottom of the steam stripping tower, a liquid phase in the reaction product is extracted to serve as a desulfurized heavy gasoline fraction, and a vapor phase returns to the steam stripping section of the steam stripping tower; and the second reactor is a heat exchange type reactor, and an external heat source flows through a coil pipe or a tube nest in the heat exchange type reactor to heat reaction materials. The gasoline fraction desulfurization method provided by the invention can reduce energy consumption, and is small in octane number loss and high in desulfurization depth.

Description

technical field [0001] The invention relates to a method and a reaction system for desulfurizing hydrocarbon oil, more specifically, to a method and a reaction system for removing sulfur compounds in gasoline fractions. Background technique [0002] As people pay more and more attention to the harmful substances emitted by automobile exhaust, countries all over the world have put forward strict requirements on the quality of automobile fuel. my country's National V Motor Gasoline Standard, which has been implemented in January 2017, and the National VI Motor Gasoline Standard scheduled to be implemented in January 2019 both require that the sulfur content be less than 10 μg / g. In order to meet the new standards, domestic refineries are faced with the task of transforming and upgrading the clean gasoline production process. my country's motor gasoline is mainly composed of catalytic cracking gasoline, accounting for about 80% of finished gasoline. However, its sulfur conten...

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Problems solved by technology

However, this method also has disadvantages. Firstly, the product after primary hydrodesulfurization still needs to be separated from gas and liquid through a high-pressure separation tank, and the obtained liquid phase enters the stripping tower again, and there is still energy consumption caused by material phase change and temperature rise and fall; secondly The secondary desulfurization reaction is carried out in the stripping section of the stripper. Due to the coupling of the reaction and the separation process, the reaction conditions are limited by the operating conditions of the existing stripper, resulting in a small adjustable range of the reaction conditions and reducing the operation of the device. flexibility

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