Brown coal drying and water recycling system based on steam recompression technology

Abstract

The invention provides a brown coal drying and water recycling system based on a steam recompression technology. The brown coal drying and water recycling system comprises a first sealing pipe type rotary drying machine, a second sealing pipe type rotary drying machine and a steam compression device. The first sealing pipe type rotary drying machine is provided with a first feeding port, a first steam inlet, a first material outlet, a first moist carrying gas outlet and a first condensate water outlet. The second sealing pipe type rotary drying machine is provided with a second feeding port, asecond steam inlet, a second material outlet, a second moist carrying gas outlet and a second condensate water outlet. The second feeding port communicates with the first material outlet. An inlet ofthe steam compression device communicates with the first moist carrying gas outlet and the second moist carrying gas outlet. An outlet of the steam compression device communicates with one or more ofthe first feeding port, the second feeding port, the first steam inlet and the second steam inlet in a controlled manner. Brown coal dry waste steam latent heat can be sufficiently utilized, and thetechnical problems that in an existing rotary drying and dehydration technology, safety is poor, heat efficiency is low, water recycling is difficult, energy water resources are wasted, and the production cost is too high are solved.

Description

technical field [0001] The invention belongs to the field of lignite drying technology, in particular to a lignite drying water collection system based on steam recompression technology. Background technique [0002] Since lignite is a low-rank coal with high volatile content, high moisture, high ash content, low calorific value, easy weathering and spontaneous combustion, the unit energy transportation cost is high when used directly, which is not conducive to long-distance transportation and storage, and lignite is directly burned When the thermal efficiency is low, and the greenhouse gas emission is large, it is difficult to develop and utilize on a large scale. Therefore, lignite needs to be dried, dehydrated and upgraded before use to reduce its water content, increase its carbon content, and thereby increase its calorific value, so as to achieve efficient and economical utilization of lignite resources. The basic principle of lignite drying and dehydration technology ...

AI Technical Summary

Problems solved by technology

However, due to the selection of the wet medium in the drying process, the dry exhaust steam contains a large amount of non-condensable gas, resulting in the dew point of the dry exhaust steam still unable to reach the expected height. Under the conventional cooling water heat exchange conditions, the water recovery rate generally cannot reach more than 50%.

In addition, the heat of water vapor (mainly the latent heat of vaporization) in the dry exhaust steam is taken away by the cooling water and is not utilized, resulting in energy loss

At the same time, due to the large amount of circulating cooling water, the resulting cooling equipment pipeline investment and pump power consumption cannot be ignored.

[0007] Based on the above-mentioned technical problems in lignite drying, there is no relevant solution; therefore, it is urgent to find an effective solution to solve the above problems

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