Catalyst for low-molecular straight-chain paraffin isomerization in Fischer-Tropsch synthesis

Abstract

The invention discloses a catalyst for low-molecular straight-chain paraffin (nC5-nC8) isomerization in Fischer-Tropsch synthesis and a preparation method and application thereof for solving the problems of low activity, poor stability and low conversion rate of an existing catalyst for low-molecular straight-chain paraffin isomerization in Fischer-Tropsch synthesis. In the preparation method, anAl2O3-ZrO2 composite oxide carrier is prepared with a coprecipitation method, a lanthanum salt is added to increase the proportion of the zirconia tetragonal phase and regulate the Al2O3 content to maintain the acidity of the catalyst, then a Ni-WO3 / Al2O3-ZrO2 catalyst is prepared with an equivalent-volume impregnation method, and thus the catalyst for low-molecular straight-chain paraffin isomerization in Fischer-Tropsch synthesis is obtained, wherein Al2O3-ZrO2 serves as the carrier of the catalyst, and the active metal components of the catalyst include 1-5 wt% of Ni, 10-15 wt% of W and 0.5-2.5 wt% of La. The catalyst has high isomerization activity and selectivity, and good repeatability and catalytic stability; besides, the reaction temperature is low, and the isomerization activity of low-molecular straight-chain paraffin can be maintained at a high temperature.

Description

technical field [0001] The invention belongs to the technical field of catalyst preparation, and in particular relates to a catalyst for Fischer-Tropsch synthesis of low-molecular linear alkane isomerization, a preparation method and an application thereof. Background technique [0002] As the requirements for environmental protection are getting higher and higher, the sulfur content can be reduced to less than 10 μg / g and the olefin content can be reduced to less than 24v% by hydrodesulfurization and olefin reduction of gasoline. Although the content of olefins and aromatics in gasoline is gradually reduced, its octane number is also greatly reduced. To reduce sulfur and olefins with little or no loss of octane, selective hydrocracking or isomerization is required. Hydroisomerization is particularly important for increasing the octane number of gasoline. The RON of isoparaffins is much higher than that of normal paraffins with the same carbon number. For example, nC 6 T...

AI Technical Summary

Problems solved by technology

However, pure zirconia has disadvantages such as small specific surface area and weak surface acidity, and is not suitable for industrial production. Some researchers choose to dope metal atoms containing p or d orbitals in zirconia (such as Ti, Ce, Al, Si etc.), the introduction of different metal atoms will cause different changes to the properties of ZrO2, such as the introduction of metal atoms Ti will increase the specific surface area of ​​the composite oxide carrier, thereby improving the catalytic activity of the catalyst; the introduction of rare earth metal atoms such as Ce will improve The thermal stability and oxygen storage capacity of the support; the introduction of metal atoms containing acidic sites such as Al will increase the adsorption capacity and surface acidity of the composite oxide support

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