Method and system for utilizing water resources in low-rank coal

Abstract

The invention provides a method for utilizing water resources in low-rank coal. The method comprises the following steps: drying low-rank coal to obtain dried low-rank coal and waste gas, and treatingthe dried low-rank coal by a gasification reduction process to obtain upgraded coal and an oil-gas mixture; treating the waste gas sequentially through a first dust removal process and a compressionprocess to obtain coal powder and superheated steam, and carrying out a reaction on the upgraded coal, the superheated steam and O2 to prepare synthesis gas containing CO and H2; treating the oil-gasmixture sequentially by a second dust removal process and an oil-gas cooling process to obtain wastewater; and mixing the wastewater, the coal powder and a coal water slurry additive to obtain coal water slurry, wherein the gasification reduction process is a chemical reaction process for heating the dried low-rank coal under an anaerobic or micro-aerobic condition. According to the method and thesystem, water resources in low-rank coal are fully recovered, the recovery rate is high, and the problems of insufficient recovery of water in the existing low-rank coal and environmental pollution are solved; and the system is simple in equipment, easy to operate and low in operation cost, wherein most of the equipment is the existing equipment.

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 utilizing water resources 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 is a coal with a long flame and a sootiness during combustion, and a coal with a low degree of coalification. The carbon content of low-rank coal is 75%-90%, without free humic acid, most of them have cohesiveness, low calorific value, long and smoky flame when burning, most of them can coke, and the volatile matter contained The content is about 10%-40%. Low-rank coal mainly has the material characteristics of high moisture and high volatility, and the typical coal type is lignite. my country is rich in coal and lacks oil and gas. How to efficiently utilize low-rank ...

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Problems solved by technology

[0004] In view of this, the object of the present invention is to provide a method and system for utilizing water resources in low-rank coal, which can recover a large amount of free water in low-rank coal and recover bound water therein, in view of the deficiencies in the prior art. The recovery rate is high, which solves the problems of insufficient water recovery and environmental pollution in the existing low-rank coal

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