Technique and system for low-rank coal moisture resource utilization

Abstract

The invention relates to a technique and a system for low-rank coal moisture resource utilization and solves the problems of insufficient moisture and heat recovery and environmental pollution during existing low-rank coal drying. The technique is characterized in that water vapor generated after drying of low-rank coal is fed to cyclone separator for removing solid particles and water drops formed by disturbance, the water vapor with dust removed is pressurized via a pressurization system prior to entering a desulfurization system for removing sulphureous components, the desulfurized water vapor is fed into a low-temperature heat utilization system for recovering low-temperature heat in the vapor and then enters a gas-liquid separation tank for separating non-condensable gas and liquid water, the liquid water is cooled by a cooling system and then fed into a condensate collection system, and dust content in condensate in the condensate collection system is less than 5ppm. The technique and the system are capable of sufficiently recovering moisture in the water vapor generated after low-rank coal drying, are environmentally friendly and have remarkable economic benefit.

Description

technical field [0001] The invention relates to the field of comprehensive utilization of low-rank coal, in particular to a process method and system for water resource utilization of low-rank coal. Background technique [0002] my country is rich in low-rank coal resources, and low-rank coal represented by lignite / sub-bituminous coal accounts for more than 55%, with reserves reaching 561.2 billion tons. Recently, Xinjiang has added about 2.19 trillion tons of coal reserves, mostly sub-bituminous coal. Low-rank coal has low degree of coalification, developed capillary pores, high oxygen content (about 20% for anhydrous and ash-free base), rich internal water, up to 30-50% total moisture, low calorific value, and poor thermal stability. Long-distance transportation, direct use as large-scale gasification raw materials has great limitations, and is currently mainly used as power fuel in local areas, with a low development rate, accounting for only 4-5% of the national coal ou...

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Problems solved by technology

Using direct contact heat and moisture exchange, the water recovery efficiency is high, and the patent also reports the subsequent upgrading and utilization of low-temperature and low-humidity flue gas after water recovery, but it does not consider fully recovering and utilizing the heat in the water vapor in the dry flue gas

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