Method for preparing synthetic gas by using volatile compound and waste water in low rank coal and system thereof

Abstract

The invention provides a method for preparing synthetic gas by using a volatile compound and waste water in low rank coal. The low rank coal is processed by a drying process to obtain dried low-rank coal and exhaust gas, and the exhaust gas is treated by a first dust removal process to obtain coal dust; the dried low-rank coal is treated by a gasification reduction process to obtain a gas-oil mixture; the gas-oil mixture is treated by a purification process to obtain a gas mixture and wastewater; the gas mixture is treated by a reforming conversion process to obtain a first synthetic gas containing CO and H2; the wastewater, the coal dust and a coal water slurry additive are mixed to obtain coal water slurry, and the coal water slurry and O2 are treated by a coal water slurry gasificationprocess to obtain a second synthetic gas comprising CO and H2; and the synthetic gas is obtained by mixing the first synthetic gas and the second synthetic gas. In the invention, the volatile compoundin the low rank coal is used for preparation of the synthetic gas, and moisture and coal dust in the low rank coal are effectively recovered to be used for making the coal water slurry, and the low rank coal is used for making the synthetic gas. With the reutilization of waste water, the wastewater discharge problem is solved.

Description

technical field [0001] The invention relates to the technical field of clean utilization of coal substances, in particular to a method and system for preparing synthesis gas by utilizing volatile matter and waste water in low-rank coal. Background technique [0002] More than half of my country's proven coal reserves are low-rank coals, and the volatile matter contained in them is equivalent to 100 billion tons of oil and gas resources. Low-rank coal mainly has the material characteristics of high moisture and high volatility. When burning, the flame is long and smokey, and the degree of coalification is low. Typical coal types are lignite and long-flame coal. my country is rich in coal and lacks oil and gas. How to efficiently utilize low-rank coal has become a major issue in today's clean coal technology. However, whether it is combustion power generation or modern coal chemical utilization, the efficiency of comprehensive utilization is extremely low because of its three...

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Problems solved by technology

[0006] In view of this, the purpose of the present invention is to address the deficiencies in the prior art, to provide a method and system for preparing synthesis gas by utilizing volatile matter and waste water in low-rank coal, not only utilizing volatile matter in low-rank coal to prepare synthesis gas, Moreover, the moisture and coal powder in low-rank coal can be effectively recovered to make coal-water slurry. Syngas is produced through coal-water slurry, waste is utilized, resources are saved, and the problems of insufficient water recovery and environmental pollution in existing low-rank coal are solved.

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