Drying, desulphurization and dehydration system and process for low-rank coal or coal slime

Abstract

The invention discloses a drying, desulphurization and dehydration system for low-rank coal or coal slime. The system comprises a superheated steam drying device; a feeding device, the superheated steam drying device and a microwave dryer are connected sequentially; an air inlet and a built-in heat exchanger of the superheated steam drying device are respectively connected with a superheated steam heat source; an air inlet of the microwave dryer is connected with an air outlet of the superheated steam drying device; an air outlet of the microwave dryer is sequentially connected with an air inlet of a dust removing device and an air inlet of a desulfuration device; the desulfuration device is also connected with an elemental sulfur recovery device; discharge openings of the microwave dryer and the dust removing device are respectively connected with a dry material bin. The invention further discloses a corresponding drying, desulphurization and dehydration process for the low-rank coal or coal slime. According to the system and the process, the drying, desulphurization and dehydration process of combining the superheated steam and the microwave is adopted to dry the low-rank coal or coal slime, and the dehydration and the desulfuration are realized at the same time. Moreover, the energy sources utilization ratio is improved, the tail gas pollution is reduced, and the elemental sulfur can be recovered, thereby achieving the purposes of energy conservation and environmental protection.

Description

technical field [0001] The invention relates to a system and process for drying low-rank coal or coal slime by using superheated steam and microwave, and capable of dehydration and desulfurization. Background technique [0002] The water content of low-rank coal or coal slime is generally high, and direct combustion as fuel will lead to problems such as low combustion efficiency; in addition, the sulfur content of coal mined in my country is also gradually increasing, and the sulfur in low-rank coal or coal slime is converting and combustion utilization process, will produce SO 2 and H 2 S gas, causing serious environmental pollution. In order to reduce the harmful effects brought by the use of low-rank coal or coal slime, it is necessary to dry and desulfurize low-rank coal or coal slime. The traditional low-rank coal or coal slime drying methods include efflux, sedimentation, fire drying and air drying. Dust is likely to be generated during the fire drying process, and ...

AI Technical Summary

Problems solved by technology

However, in the stage of drying at reduced speed, the dry moisture of low-rank coal or coal slime is mainly internal moisture, and the changing law of drying rate has been related to the properties and internal structure of the material. The vaporization rate of the surface of the material to the drying gas, the evaporation has been controlled by the surface vaporization to the internal diffusion control, and the drying rate drops sharply at this stage, and the energy utilization rate decreases

Therefore, in the later stage of drying, that is, the slow-down drying stage, there will be shortcomings such as low drying rate, long drying time and large energy consumption, and the process needs to be improved.

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