Coal pyrolysis method

Abstract

The invention provides a coal pyrolysis method, which comprises the following steps of: a) crushing raw coal comprising brown coal into the first powdered coal with the mean particle size of 1.5 to 3.5mm; b) drying the first powdered coal in a drying device by one step to prepare the second powdered coal with the water content of less than or equal to 2.5 weight percent at the temperature of between 80 and 100 DEG C, wherein the axial inclination of the drying device during drying is 15 degrees; and c) mixing the second powdered coal and coal ash and performing pyrolysis reaction in a pyrolysis reactor so as to prepare a first gas product and a first solid product. By pretreating the brown coal in the coal pyrolysis method, the second powdered coal of which the granularity, temperature and water content meet the requirements is directly obtained, and the second powdered coal can directly undergo the coal pyrolysis reaction; and in the process, by crushing the coal into the granularitywhich meets the proper requirement, the coal pyrolysis method has the advantages of capacity of avoiding deep drying from generating more fine ash in the drying process, contribution to reducing the energy consumption and simplifying the technology, and capacity of improving the utilization effect of the brown coal.

Description

technical field [0001] The invention belongs to the field of coal chemical industry, and in particular relates to a coal pyrolysis method. Background technique [0002] Lignite, also known as firewood coal, and its English name is Lignite coal, is a brownish-black, dull, low-grade coal with a low degree of coalification between peat and bituminous coal. It is characterized by high moisture, large porosity, and volatile High scores, low calorific value, contain varying amounts of humic acid. Lignite reserves are abundant, and under the condition of relatively scarce resources at present, the development and utilization of lignite has a good prospect. However, due to the high water content of lignite, which can reach 15wt% to 50wt%, when directly participating in combustion for power generation, water evaporation will take away a large amount of heat energy, resulting in large heat loss and reduced power generation efficiency; if lignite is directly used for coal gasification...

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Problems solved by technology

[0006] In the above process, the lignite is first crushed to ≤6.3mm in the lignite pretreatment system, then dried to 9wt%~12wt%, and then sent to the riser deep dryer for deep drying, during the deep drying process , the drying gas and coal powder flow side by side, the drying gas not only plays the role of drying coal powder, but also plays the role of transporting coal powder, the inside of the deep drying pipe is similar to fluidization, so the drying gas coming out of the deep drying pipe will carry A large amount of coal powder must be separated by at least two-stage cyclone separators to obtain exhaust gas that meets the emission requirements; deep drying and subsequent cyclone separation steps increase the energy consumption of the entire process and also complicate the process

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