Technique for producing oil products by fischer-tropsch synthesis

Abstract

The invention relates to a technological method for preparing oil products by the Fischer-Tropsch synthesis. In the technological method, a FT synthesis process comprises a first-stage FT synthesis process and a second-stage FT synthesis process; in particular, the technological method comprises the following steps: (1) synthesis gases are subjected to FT synthesis reaction in a first-stage synthesis reactor; (2) a part of tail gases from the first-stage synthesis reactor are circularly returned to an entrance of the first-stage synthesis reactor, and another part of the tail gases enter a second-stage synthesis reactor for the further FT synthesis reaction; (3) a part of tail gases from the second-stage synthesis reactor are circularly returned to an entrance of the second-stage synthesis reactor, and another part of the tail gases are used for reclaiming low-carbon hydrocarbons and hydrogen gases and then are used as fuel gases; and (4) by utilizing the recovered hydrogen gases, the hydrocarbon products in the first-stage synthesis reactor and the second-stage synthesis reactor and the hydrocarbon products which are obtained by separating and recovering the tail gases are subjected to hydrogenation and purification and then are fractionated to generate various oil products. Compared with prior art, the technological method has the characteristics of economy, flexibility, low cost and the like.

Description

technical field [0001] The invention relates to an oil production method, in particular to a process for producing liquid oil by Fischer-Tropsch synthesis using synthetic gas as a raw material. Background technique [0002] Synthesis gas is produced from coal or natural gas. Synthesis gas is synthesized by Fischer-Tropsch synthesis into hydrocarbons, and hydrocarbons are processed into liquid oil in one step. The indirect coal liquefaction process is an important strategy for clean energy utilization and energy substitution in the 21st century. One of the directions of technological development. [0003] According to the main results of existing literature review, the Fischer-Tropsch synthesis process is briefly described as follows: [0004] Syngas as H 2 With the mixed gas mainly composed of CO, the Fischer-Tropsch synthesis reaction occurs under the action of the Fischer-Tropsch synthesis catalyst to generate liquid hydrocarbon products. The type and quantity of produc...

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Problems solved by technology

[0009] (1) This process is only for the low-temperature Fischer-Tropsch synthesis process, and the reactor type suitable for different Fischer-Tropsch synthesis processes cannot be configured according to product requirements

[0010] (2) The corresponding relationship between the primary and secondary synthesis reactors is not clear in the disclosed scheme of the process. According to its embodiment, the implicit scheme is that each primary synthesis reactor corresponds to a secondary synthesis reactor. The inlet gas volume of the first-stage synthesis reactor is much lower than that of the first-stage synthesis reactor, so the size of the second-stage synthesis reactor is also much lower than that of the first-stage synthesis reactor, and the processing capacity of the first-stage and second-stage single reactors is quite different

[0011] (3) In the disclosed scheme of the process, the primary tail gas is recycled back to the primary reactor and enters the secondary reactor without any treatment, and the secondary tail gas is recycled back to the secondary reactor without any treatment. Other components in the gas points (mainly CO 2 ) In addition to reducing the reaction partial pressure of the effective gas and increasing the gas flow rate, the design diameter of the reactor will be increased, and the cycle power consumption will also increase

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