Method for preparing high carbon hydrocarbon through photocatalytic activation of biomethane

Abstract

The invention provides a method for preparing high carbon hydrocarbon through photocatalytic activation of biomethane. The method comprises the steps that a biomethane CO2 removing system, an air pump, a preheater and multiple stages of parallel photocatalytic activation reactors are included, and unconverted methane mixture gas is used circularly and repeatedly; hydrogen generated in a photocatalytic activation reaction is permeated through a palladium hydrogen permeation membrane separator and recycled through a hydrogen vacuum pump, methane, ethane, ethylene, propane and butane are impermeable, high carbon hydrocarbon is recycled through a condensation cooler and a gas separator, uncondensed gas and methane are merged and return to a reaction system. According to the method, the hydrogen byproduct can be recycled, due to the fact that a multi-stage parallel photocatalytic activation inducing reaction is adopted, the staying time of membrane is prolonged, the conversion rate of membrane is increased, generation of ethane, ethylene, propane and butane in the reaction system is promoted, the alkanes serve as a reaction auxiliary of membrane and an initiator of optical free radical chains to be used circularly and repeatedly, therefore, the temperature of the reaction for converting membrane into high carbon hydrocarbon is significantly lowered, energy resources are saved, and the production cost of high carbon hydrocarbon is reduced.

Description

technical field [0001] The invention relates to a biomethane multistage parallel photocatalytic activation reactor system for the preparation of high carbon hydrocarbons C 4 + The method belongs to the field of chemical technology. Background technique [0002] Owing to the inexhaustible availability of renewable resources, the abundant reserves of biomethane (i.e., biogas) and natural gas have attracted widespread attention as effective feedstock sources of high-carbon hydrocarbons. Making full use of this resource is a need to reduce greenhouse gas emissions and a need of a new era, where clean technologies and renewable energy will eventually replace fossil fuels, and efforts are being made to produce hydrogen and hydrocarbons from biomethane and natural gas. However, the development and utilization of biomethane and natural gas are constrained by high transportation costs, which can be reduced by converting methane into high-carbon hydrocarbons. [0003] The following...

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Problems solved by technology

[0014] In order to overcome the problems of high-temperature dehydrogenation of methane as high as 700-900°C, high energy consumption, and high-temperature coking and carbonization existing in the prior art, the present invention aims to provide a biomethane photocatalytic activation induction, anaerobic free radical reaction, C 4 + The method of gas-liquid separation; it is known that the boiling point of n-butane is -0.5°C (propane is -42°C), and the relative density is 2.46kg / m 3 , melting point -138.4°C, critical temperature 151.9°C, critical pressure 3.79MPa, saturated vapor pressure of n-butane at different temperatures: -20°C / 45.21kPa, 0°C / 103.2kPa, 20°C / 208.1kPa, 40°C / 380.2 kPa, 60℃ / 642.0kPa; a small amount of ethane, propane and butane induced and generated by photocatalytic activation can be used as a co-reactant of methane in the photocatalytic reactor, providing an initiator of methyl free radicals for methane dehydrogenation , thereby greatly reducing the formation of higher carbon hydrocarbons C by dehydrogenation of methane 4 + The temperature and difficulty of the reaction

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