Grading pyrolysis and gasification and high-temperature tar removal and dust removal integrated process for biomass circulating fluidized bed

Abstract

The invention discloses a grading pyrolysis and gasification and high-temperature tar removal and dust removal integrated process for a biomass circulating fluidized bed. Biomass enters the middle-lower part of a carrying fluidized bed and is mixed with high-temperature synthesized gas and heat carriers of a turbulence fluidized bed, a mixture is heated, a pyrolysis reaction occurs, and the mixture is carried to go upwards; pyrolyzed oil gas has gas-phase catalytic pyrolysis on the middle-upper part of the carrying fluidized bed, and tar is pyrolyzed into methane, ethane and others; after a reaction, the heat carriers, semi-coke and fuel gas are subjected to four grades of gas-solid separation, in the first grade of separation, the large-particle carriers and the semi-coke are used as a fuel gas pyrolyzing catalyst and a filtering material for filtering and dust removal and enters a movable bed filter device, then super-thin dust is separated out, then fuel gas pyrolyzing catalyst andthe filtering material return to the turbulence fluidized bed for a gasification reaction, and the super-thin dust is used as silicon-potassium fertilizer products to be delivered out; in the second grade of separation, the medium-small particle carriers and the semi-coke are directly circulated back to the turbulence fluidized bed, in the third grade of separation, fine particles are discharged as silicon-potassium fertilizer products, in the four grade of separation, the movable bed filter device conducts secondary catalytic pyrolysis on a small amount of tar in the fuel gas to obtain methane, ethylene and others, meanwhile, the super-thin dust is removed, and purified fuel gas is delivered out as products.

Description

1. Technical field [0001] The invention provides an integrated process of biomass circulating fluidized bed graded pyrolysis gasification and high-temperature tar removal and dust removal, which belongs to the field of biomass energy. 2. Background technology [0002] my country's biomass resources are huge, and it is a low-sulfur and CO2 "zero emission" renewable and clean energy, which plays a vital role in world energy security and carbon emission reduction. [0003] As one of the main methods of large-scale, efficient and clean utilization of biomass energy, gasification technology converts biomass with low energy density from solid state into combustible gases such as CO, H2 and CH4 with lower molecular weight and high grade. With the advantages of stable combustion, high thermal efficiency, low pollution, especially low PM2.5 index, it can be widely used in various fields of industrial and agricultural production, such as the current centralized gas supply, heating and...

AI Technical Summary

Problems solved by technology

[0005] The biomass special-shaped circulating fluidized bed gasification process (CN102942965A) and the biomass special-shaped circulating fluidized bed gasification furnace (CN103102990A) proposed by the inventors, by pyrolyzing the raw materials in the presence of hydrogen, the coarse particles are circulated back to turbulent fluidization Bed semi-coke gasification, fine particles are discharged as silicon and potassium fertilizer, which not only solves the problems of low calorific value of biomass gasification, difficult tar treatment, and small scale, but also rationally utilizes the silicon and potassium resources of biomass to obtain high methane content. However, it is still difficult to completely eliminate tar and fine ash under conditions such as changes in the nature of raw materials and operating conditions, and it is difficult to meet the requirements for subsequent power generation and heating

In the existing traditional methods for removing tar and dust, cyclone separation and dust removal can only remove dust above 5 μm, and ultrafine particles and tar are difficult to remove; washing with water can remove tar and dust at the same time, but it will cause secondary pollution of phenol-containing wastewater , waste energy and resources; packing filter can remove tar and dust at the same time, only need to add filter material, and the filter material is easy to block, and the tar covered on its surface is difficult to remove, which increases the operating cost and investment; thermal cracking needs to consume part Gas or semi-coke produces a high-temperature zone to promote tar decomposition, while the catalytic cracking catalyst is deactivated by carbon deposition and high cost. It is urgent to develop a low-energy, low-cost integrated process of gasification, detar, and dust removal that can simultaneously eliminate tar and dust.

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