Method for preparing synthesis gas from biomass and system adopted by method

Abstract

The invention belongs to the field of biomass energy, and particularly relates to a method for preparing synthesis gas from biomass and a system adopted by the method. The method comprises the following steps of (1) feeding a pretreated biomass raw material into a microwave pyrolysis reactor for reaction to obtain a pyrolysis volatile component and a pyrolysis solid-phase material, (2) feeding large-particle pyrolysis solid-phase materials in the pyrolysis solid-phase materials into a biochar gasifier to obtain a biochar product and crude synthesis gas under the action of an activating agent,and (3) feeding the pyrolysis volatile component, the small-particle pyrolysis solid-phase material and the crude synthesis gas into a tar cracker, and carrying out tar removal treatment and reformingreaction of hydrocarbon small molecules under the action of working gas to prepare the target product of biomass synthesis gas. The method is convenient for reaction process control and product regulation and control, can significantly reduce the process cost of preparing the synthesis gas from the biomass, and is high in target product quality.

Description

technical field [0001] The invention belongs to the field of biomass energy, and in particular relates to a method for producing synthesis gas from biomass and a system used therein. Background technique [0002] As an important chemical raw material, synthesis gas has important application value in the synthesis of methanol, dimethyl ether, light olefins and fuel oil. At present, synthesis gas mostly comes from petroleum refining and coal gasification process, but fossil energy is non-renewable and there are pollution problems of harmful gases such as sulfur and nitrogen in the process. Synthesis gas needs to be added with impurity and coke removal process, which greatly affects the production of synthesis gas. Develop applications at scale. Biomass is a cheap and large-scale renewable energy, and the content of sulfur and nitrogen in biomass is generally lower than that of conventional fossil-based raw materials. Therefore, it is of great practical significance to explore...

AI Technical Summary

Problems solved by technology

However, in the actual development and application process, it is found that the high volatile content of biomass will lead to a large amount of tar in gasification, which seriously affects the purity and composition of syngas

In response to the above problems, two main biomass gasification technology routes have been developed at present: one is the biomass direct water vapor technology route, which includes the gasification reaction of biomass directly with water vapor in a fixed bed or a fluidized bed. The biggest problem with this route is that combustion gas needs to be introduced during the gasification process, which will dilute the effective components of the gas product, and high-temperature steam (1000°C) is used instead of conventional medium-low temperature steam to obtain higher-quality syngas products, but the preparation of high-temperature steam requires special equipment and consumes additional energy, resulting in high overall costs

The other is the biomass pyrolysis gasification technology route. The biggest advantage of this technology is that it is carried out under oxygen-barrier or anaerobic conditions, and can obtain higher-quality syngas products, but the amount of tar produced is more than the direct water of biomass. Steam technology route, which limits the further application of this technology

[0003] Aiming at the problem of excessive tar generation in the biomass pyrolysis process, Chinese invention patent 201910381117.1 discloses a biomass synthesis gas production method and its device, which uses a hydraulic mechanical furnace to gasify biomass and uses biomass The sensible heat of the syngas heats the biomass for drying and gasification. By capturing the tar in the syngas and using it for recycling combustion, the tar content in the syngas is reduced and the energy consumption in the biomass gasification process is reduced. However, this method The use of alkaline solution to capture tar has the problems of waste liquid treatment and discharge, which is not conducive to large-scale application

Chinese invention patent 201910392371.1 discloses a biomass microwave catalytic pyrolysis method and its device. The biochar produced after biomass pyrolysis is used to remove tar in the pyrolysis gas, and then enters catalytic cracking to obtain biomass synthesis. Gas products, the biggest feature of this method is that pyrolysis, tar removal, catalytic reforming and catalyst regeneration are coupled in the microwave integrated device, and the microwave power is reasonably adjusted according to the heat absorption and release of each reaction, which improves the energy utilization efficiency. In the method, biochar is only used for tar removal and catalyst regeneration, resulting in the consumption of a large amount of biochar, which seriously affects the high-quality utilization of biochar

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