Method for preparing synthetic gas by three-phase type biomass pyrolysis-gasification-catalytic reforming

Abstract

The invention belongs to the technical field of energy chemical industry. The process for preparing synthetic gas by biomass pyrolysis and gasification is divided into three steps of biomass low-temperature pyrolysis, coke or semi-coke high-temperature gasification and crude synthetic gas / tar catalytic reforming. The three reaction steps are successively and continuously carried out in three relatively independent spaces of an upper pyrolysis hearth, a lower gasification hearth and a catalyst bed inside the same gasification reaction device so as to finally obtain the high-quality synthetic gas. The method provided by the invention has high carbon conversion rate, produces no secondary pollution and is simple to realize. In addition, required biomass is rich in reserves and can be regenerated, thus realizing integrated sustainable utilization of resource, energy and environment.

Description

technical field [0001] The invention belongs to the technical field of biomass energy chemical industry, and in particular relates to a technology and method for producing synthesis gas by three-stage biomass pyrolysis gasification-catalytic reforming. technical background [0002] With the improvement of human living standards, people rely more and more on energy. However, due to the non-renewability of fossil fuels and their limited reserves, fossil energy has been increasingly exhausted, and the environmental crisis has become increasingly obvious. Today, seeking and developing new energy sources, especially renewable energy sources with little environmental pollution, has attracted global attention. Biomass is a variety of organisms formed through photosynthesis. It is directly or indirectly derived from the photosynthesis of green plants and can be converted into conventional solid, liquid and gaseous fuels. It is widely distributed and available in large quantities. It...

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Problems solved by technology

The residual carbon contains carbon with high calorific value without gasification, which greatly reduces the overall gasification efficiency; tar is a hydrocarbon with a very complex composition, mainly a derivative of benzene, which exists in a gaseous state at high temperatures, and at low temperatures (<200 ° C ) exists in a viscous liquid state and is difficult to remove. Even if it is removed, part of the calorific value of the syngas will be discharged along with the removed tar, resulting in a loss of gasification efficiency

[0005] Biomass gasification technology is currently in the initial stage of large-scale commercial development. There are many attempts and practices. Whether it is the application of fixed bed or fluidized bed gasification reactors, in general, the current commercial development of biomass gasification The main problems encountered in the technology are: 1. Conventional gasification technology, because the pyrolysis gasification process is carried out under the same conditions in the same reactor, the pyrolysis and gasification processes are not separated, so that the synthetic gas produced There is a complex composition of the gas produced, and the H in the produced gas 2 2. Conventional gasification efficiency is low, carbon residue is high, gasification gas calorific value is low, and the calorific value is unstable; and due to the existence of heavy metal dialysis problems in residual carbon, fly ash and ash, there are still There is a secondary pollution problem; 3. The synthesis gas generated during the gasification process is not completely cracked and removed due to the tar, so that the quality of the synthesis gas is not high, and the H 2 and CO content is low, the impurity gas CH 4 , CO 2 and other short-chain gaseous alkanes and olefins have high content, and the gas purification process is complex; 4. The two-stage (201020268361.1 and 200910033191.0) and three-stage (200710047695.9 and 200710011214.9) biomass gasification that has been developed to produce syngas (or rich The hydrogen synthesis gas) system separates the biomass pyrolysis (combustion) and gasification (and catalytic reforming) processes, so that each reaction process can be fully carried out under separate reaction conditions, and the H in the gas production is improved. 2 and CO concentration, but each reaction is carried out in a separate reactor, which increases the complexity of the reaction system, increases the operating cost, and limits the expansion of the device's processing capacity, which cannot achieve high-efficiency and low-cost biomass gas production. The purpose of obtaining refined synthesis gas

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