Process for carrying out strengthening circulation, stage grinding and quality improvement on lignite by utilizing superheated steam and system thereof

Abstract

The invention relates to a process for carrying out strengthening circulation, stage grinding and quality improvement on lignite by utilizing superheated steam and a system thereof. The method comprises the following steps: (1) carrying out grinding on the raw material lignite; (2) burning one part of coal blocks / powder to produce high-temperature flue gas serving as a heat source and carrying out air separation and dring on the other part of coal blocks / powder requiring to be subjected to quality improvement; (3) in the process of air separation, adopting the high-temperature flue gas from the step (2), carrying out drying, separation and dust removal on the qualified coal blocks / powder conforming to the standard grain diameter after air separation, collecting the qualified coal blocks / powder, sending the qualified coal blocks / powder to the forming process, making the unqualified coal blocks / powder drop in a grinding ventilating device to carry out grinding and drying, then continuously completing deep drying by air separation and repeating the steps, wherein the oxygen content in the flue gas is less than 8 percent; and (4) sending one path of waste gas subjected to air separation and drying to the washing process and returning the other path of waste gas serving as a return tail gas part to the step (2) so as to prepare the high-temperature flue gas and carry out air separation. The process has the advantages of safety, energy saving, environment protection, high efficiency, stability and the like.

Description

technical field [0001] The invention relates to a lignite superheated steam enhanced cycle graded pulverization process and a system thereof. Background technique [0002] Due to its low calorific value, high water content, easy weathering and fragmentation, and easy spontaneous combustion, lignite has brought many difficulties to its combustion, transportation, and storage. How to realize the efficient utilization of lignite has become an urgent problem to be solved. For this reason, a lot of research work has been carried out both at home and abroad. After the lignite is dried, it is made into a briquette with a certain particle size and compactness, which will make its performance better than that of the raw lignite coal in all aspects, and can effectively solve the problems that the lignite is easy to be weathered and broken, and easy to spontaneously combust during transportation and storage. Therefore, lignite drying molding technology has become one of the main rese...

AI Technical Summary

Problems solved by technology

[0007] Aiming at the drying problem of lignite with high volatile content, high water content, and easy spontaneous combustion, and the deficiencies of the existing drying process, the present invention provides a lignite superheated steam enhanced circulation classification pulverization process and its system

Based on the drying theory of superheated steam, this technology realizes the optimized combination of crushing, winnowing, crushing, drying and other technologies, and solves the problems of high energy consumption, difficult system control, unstable operation and low safety performance in the current lignite drying technology. question

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