Modified nano molecular sieve catalyst for cracking endothermic hydrocarbon fuels and preparation method

Abstract

The invention relates to a nano molecular sieve catalyst for cracking of endothermic hydrocarbon fuel and a preparation method. The preparation method uses nano-scale Na type molecular sieve raw powder as a raw material, firstly prepares an H-shaped molecular sieve, and then carries out modification preparation by a grafting method; and a proportion of the nano molecular sieve to a grafting reagent is 0.016-1.560 mmol / g (grafting reagent / molecular sieve). The method uses the nano molecular sieve with the advantages of large specific surface area, short pore canal, more surface active sites and the like as a modification precursor of the catalyst, uses organic chlorosilane, organic siloxane or Grignard reagent and the like as a modified reagent, and adopts the grafting method to carry out organic functional modification for the surface of the nano molecular sieve so as to obtain the nano molecular sieve catalyst. The catalyst used for catalytic cracking reaction can make up the defects of easy carbon deposit, easy inactivation of the catalyst and the like in the prior thermal cracking and catalytic cracking process of the endothermic hydrocarbon fuel, reduces the heat transmission resistance of a pipeline, and improves the cracking rate of the fuel.

Description

technical field [0001] The present invention relates to the active cooling technology of hypersonic aircraft, in particular to a nano-molecular sieve catalyst and preparation method for cracking endothermic hydrocarbon fuels, in particular to a stable and dispersed nano-molecular sieve used in the process of cracking hydrocarbon fuels catalyzed by nano-molecular sieves catalyst. Background technique [0002] When a hypersonic vehicle flies at high speed, it generates a lot of heat, which affects its normal operation. The heat-absorbing fuel can absorb heat and undergo cracking to generate small molecular compounds, which reduces the heat load of the aircraft and improves the combustion performance of the fuel itself. Chinese patent CN101121897A adopts the coating catalytic technology to coat the zeolite molecular sieve loaded with precious metals on the inner wall of the pipe, and when the fuel flows through the pipe, the heat conducted by the pipe wall is used to catalyze ...

AI Technical Summary

Problems solved by technology

Its disadvantages are: it is easy to form carbon deposits on the surface of the molecular sieve during the cracking process to cover the surface active sites, which eventually leads to a decrease in the catalytic performance of the molecular sieve or even deactivation; and the molecular sieve is coated on the inner wall of the fuel pipeline, which increases the heat transfer resistance of the pipeline wall , is not conducive to the diffusion of heat

If the molecular sieve catalyst is filled in the fuel pipeline, it will increase the flow resistance of the fuel in the pipeline, and the carbon deposits in the cracking process will also be adsorbed on the catalyst, which will easily lead to catalyst deactivation or even blockage of the pipeline, which is not conducive to the normal operation of the aircraft

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