Energy saving and environmental protection lignite briquette preparation process and system

Abstract

The invention discloses an energy-saving environment-friendly lignite briquette preparation technology which comprises the steps of lignite drying with superheated steam, forming and briquette surface tiny dust treatment and specifically comprises the following steps of: 1) breaking and screening raw lignite, and feeding into an internal-heating fluidized bed dryer; 2) feeding saturated steam from a back pressure unit of a plant area into a built-in heat exchanger in the internal-heating fluidized bed dryer, performing indirect heat exchange of the lignite powder to remove moisture, drying until the lignite powder is qualified in moisture, and discharging the lignite powder into a forming and briquette surface tiny dust treatment device from the bottom end of the internal-heating fluidized bed dryer; and 3) performing indirect heat exchange on the saturated steam to obtain condensate water, wherein some of the condensate water enters a boiler water supply system, and the other condensate water is fed into an evaporator; discharging the steam generated by the removed moisture of the lignite powder together with a fluidized carrier gas from the top of the internal-heating fluidized bed dryer in a state of superheated steam; and performing multi-level dust removal, wherein some of the lignite powder returns to the internal-heating fluidized bed dryer, and the other lignite powder is recycled. The invention also discloses a system for implementing the technology.

Description

Technical field [0001] The invention relates to a lignite preparation process, in particular to an energy-saving and environment-friendly lignite briquette preparation process. Background technique [0002] At present, low-rank coals, like lignite and low-degraded bituminous coal, are distinguished by their high moisture content (30%-60%) and low calorific value. In addition, due to the late coal formation, its chemical reaction activity is high. It is easy to weather and spontaneously burn, and it is not conducive to long-distance transportation. If used as fuel and chemical raw materials, high water content greatly reduces its calorific value, and causes large exhaust emissions during the combustion process and serious environmental pollution. As the world's energy resources become more and more tense, the use of low-rank coal has been paid more and more attention. How to reduce its moisture, increase its calorific value, and expand the scope of application and use of low-ran...

AI Technical Summary

Problems solved by technology

With binder molding technology, there are high coal cost, complicated process, and defects of increasing ash content and reducing calorific value. In addition, the addition of binder will increase the emission of pollutants and increase the environmental pressure during combustion.

The patent 201010262471.1 applied by the applicant proposes a method in which the dried and upgraded lignite enters the molding machine from the feeding system, and is screened, cooled and dedusted, and the unqualified briquettes are remolded to finally obtain qualified briquettes, which does not involve lignite drying and upgrading Recovery and utilization of waste heat steam heat in the process, full recovery and utilization of moisture released from drying, steam replacement and nitrogen protection measures for explosion protection in the molding process, mixing and molding of dry and dust-removing fine materials, self-balancing of energy consumption in the factory area, etc.

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