System and method for treating low-rank coal

Abstract

The invention discloses a system and method for treating low-rank coal. The system comprises: a low-rank coal screening device; a lump coal hot-blast combined separating device, having an oversize low-rank coal inlet, a first hot blast inlet and a first clean coal outlet; a pulverized coal hot-blast and air separating device, having an undersize low-rank coal inlet, a second hot blast inlet and a second clean coal inlet; a crushing device, having a clean coal inlet and a pulverized coal outlet, with the clean coal inlet connected with the second clean coal outlet; a forming device; a pyrolysis device, having a feed inlet, a semicoke outlet and a pyrolysis oil and gas outlet, with the feed inlet connected with the first clean coal outlet and a ball outlet; a waste heat recovery device, having a semicoke inlet, a cooled semicoke outlet and a hot blast outlet, with the hot blast outlet connected with the first hot blast inlet and the second hot blast inlet. The system enables a significant increase in the refuse discharging rate for low-rank coal and therefore an increase in the quality and yield of pyrolysis products in a subsequent pyrolysis process, and by recovering waste heat generated in the pyrolysis process for use in the refuse discharging process, a significant reduction may be given to energy cost.

Description

technical field [0001] The invention belongs to the technical field of coal chemical industry, in particular, the invention relates to a system and method for processing low-rank coal. Background technique [0002] my country's coal resources are characterized by rich coal, poor oil, and little gas. The position of coal in my country's energy resources will not change for a long period of time. In coal resources, low-rank coal reserves are abundant. According to the prediction of international geologists, low-rank coal accounts for about 60% of coal resource reserves. It is one of the main energy sources that can be used in the future. It is mainly distributed in Australia, the United States, Russia, and China. , Indonesia, Germany and Eastern European countries, etc. Low-rank coal mainly includes non-caking coal, weakly caking coal, long-flame coal and lignite, etc., which have the characteristics of high moisture, low density, high volatile content, non-caking, strong che...

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Problems solved by technology

[0003] Although the mineral impurities in low-rank coal can be removed by separation, the full contact between coal and water in the process of wet separation increases the moisture content of the coal preparation product, reduces the calorific value of the product, and partially offsets the effect of coal washing. The goals of quality improvement and dehydration are contradictory, and the surface moisture of coal in the process of dry separation at room temperature makes the probability of adhesion between particles high, and the effect of gangue discharge is poor

Although the independent drying and low-temperature carbonization technology can increase the calorific value of low-rank coal to a certain extent, the mineral impurities such as ash and sulfur in the upgraded coal affect the quality of subsequent processed products, and compounds such as sulfur and nitrogen cause pollution to the environment and equipment corrosion

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