Gasification-flash pyrolysis graded utilization method for biomass and low-rank coal

Abstract

The invention relates to a gasification-flash pyrolysis graded utilization method for biomass and low-rank coal and mainly solves the problems that the tar yield is low, the low-rank coal is difficultto use and excessively depends on heat carriers and the like in the prior art. The method adopts combination of technologies for preparing synthesis gas through gasification and preparing tar throughflash pyrolysis and mainly comprises steps as follows: a mixture of biomass and the low-rank coal enters a pyrolysis furnace through a feeding device, is heated by high-temperature circulating semi-coke from a gasifier and is subjected to flash pyrolysis at a high linear speed, volatile components are separated out, and semi-coke is obtained; the volatile components are fed into a condenser by agas-solid separation device and is condensed, a tar product with biomass oil as a main component is obtained, the semi-coke is fed into the gasifier and reacts with a gasifying agent, and the synthesis gas and the high-temperature circulating coke are produced; after separation, the synthesis gas is purified by a purification device and processed into a chemical raw material, and the high-temperature circulating semi-coke is fed into a pyrolysis furnace and supplies heat continuously to the raw materials for pyrolysis. The method can be applied to the technical field of the coal chemical industry.

Description

technical field [0001] The invention belongs to the technical field of biomass and coal pyrolysis and gasification classification and utilization, and particularly relates to a method for realizing the co-production of synthesis gas and tar by using biomass and low-order coal gasification-flash pyrolysis classification. Background technique [0002] my country is a country with coal as its main energy structure, which will not change for a long time in the future. According to statistics, coal accounts for 66% of my country's primary energy consumption structure. With the increasing shortage of petroleum resources, effective utilization of coal resources has become a strategy for sustainable energy development in my country. my country's low-rank coal reserves account for more than 55% of the total coal resources, but it has high moisture content, low coalification, and low direct combustion efficiency, which not only wastes resources but also pollutes the environment, causi...

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Problems solved by technology

However, the addition of heat carrier not only increases the cost of raw materials, but also brings many difficulties to the subsequent separation process, making the operation of the entire process cumbersome, and there are problems such as wear and tear on equipment and large power consumption.

[0006] In order to solve the above-mentioned difficulties in the traditional process, the Chinese invention patent CN102504842A proposes a pyrolysis-gasification-combustion three-fluidized bed device, which aims to realize the syngas-tar co-production, but the pyrolysis device of this process uses a bubbling bed Reactor, the residence time of medium and low-rank coal in the reactor is widely distributed, and the residence time is long, which reduces the selectivity of the target product tar, which is not conducive to the generation of high-quality tar

The University of Tokyo (Chemical Engineering Journal, 164 (2010) 221-229; Chemical Engineering Science, 66 (2011) 4212-4220) proposed a gasification pyrolysis staged utilization process, which achieved precise control of the pyrolysis time. The separation of pyrolysis gas-solid products is realized in front of the gasifier, which avoids the inhibitory effect of volatiles on semi-coke gasification to produce syngas. However, this process uses quartz sand as the heat carrier material, which leads to serious equipment wear and tear.

[0007] Although the existing pyrolysis-gasification staged utilization technology solves the shortcomings of traditional gasification to syngas and pyrolysis to oil to a certain extent, due to the limitation of the process flow, the yield of tar is significantly reduced, or due to external heating The carrier causes problems such as excessive energy consumption and equipment damage.

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