Low-quality fuel pyrolysis process

Abstract

The invention discloses a low-quality fuel pyrolysis process. The process comprises the following steps: by mutually combining a coke dry quenching technology and a fluidized bed pyrolysis technology, mixing coke quenching gas absorbing semi-coke heat with a part of high-temperature flue gas to be used as a fluidizing medium, returning cooled fluidized gas to a coke dry quenching furnace to be used as the coke quenching gas, and using the high-temperature flue gas obtained after burning pyrolysis gas as a system heat source. The low-quality fuel pyrolysis process adopts the fluidized bed rapid pyrolysis technology, and effectively absorbs the waste heat of high-temperature semi-coke and improves the heat efficiency of a system at the same time; moreover, the fluidizing medium and a coke quenching medium of the system are coupled for use so as to ensure the tar yield, reduce the coke quenching cost, and achieve the synchronous production of tar and the semi-coke by using the fluidized bed technology.

Description

technical field [0001] The invention relates to the field of chemical application technology, in particular to a low-quality fuel pyrolysis process. Background technique [0002] Low-quality fuels represented by lignite and lean coal have a total reserve of more than 110 billion tons in my country. They have the characteristics of high water content, oxygen content and volatile matter, low carbon content and calorific value. These low-quality fuels are buried shallow and easy to be exploited on a large scale, but they are not suitable for long-distance transportation because of their low mechanical strength, easy weathering, fragmentation, spontaneous combustion, and difficult chemical processing. They are also not suitable for direct combustion as fuel for power generation, as direct combustion is less heat efficient and emits 20% more greenhouse gases than burning high-quality anthracite coal. The above characteristics have greatly restricted the application of low-qualit...

AI Technical Summary

Problems solved by technology

[0004] The fluidized bed pyrolysis process is widely used due to its fast reaction speed and high tar yield. However, this process usually uses solid particles as the heat source carrier. The semi-coke and solid particles produced during the pyrolysis process are fine and mixed together, making it difficult to separate , can only be burned, so the production process usually does not get the finished semi-coke, such as patent No. 200710063368.2 and 200910272712.8

Although the patent No. 200910215125.5 can use the fluidized bed pyrolysis process to produce semi-coke and tar, its semi-coke products need to be cooled by an external medium, which consumes additional system heat and increases the energy consumption of the production system, and its fluidization medium is The use of uncooled combustible gas causes a large amount of tar vapor carried in the combustible gas to flow back into the fluidized bed for secondary decomposition, and becomes a small molecule flammable alkane gas, which greatly reduces the tar yield of the system and increases the system efficiency. Cost of production

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