Method for improving quality of brown coal with externally heated rotary furnace

Abstract

The invention provides a method for improving quality of brown coals with an externally heated rotary furnace. The method comprises the following steps: drying and desorbing a raw material brown coals at a temperature of 100 DEG C to 300 DEG C in a rotary drying furnace; thermally cracking the dried and desorbed brown coals in a rotary carbonization furnace; heating and keeping the brown coals at a temperature of 450 to 700 DEG C through hot air from an outer jacket for thermal cracking for 40 min to 2 h; as for semi coke obtained after thermal cracking, quenching the resultant semi coke in a rotary cooling furnace and allowing the semi coke to pass through a screening device so as to obtain a finished product of semi coke with different particle sizes; as for high temperature crude coal gas containing tar obtained after thermal cracking, allowing the resultant high temperature crude coal gas containing tar to pass through a tar separating and purifying device so as to obtain a finished product of tar with high quality and a finished product of coal gas with a high calorific value, delivering one part of the finished product of coal gas and air into a combustion furnace for combustion, and delivering the combusted hot flue gas back to the jacket of the rotary carbonization furnace as a heat source. The invention enables the utilization rate of the raw material brown coals and the available value of the coal gas to be improved and treating capacity of a purifying device for coal gas to be reduced; dry quenching of coke is employed and the discharge of the coke is continuous, thereby improving the quality of semi-coke, saving energy and reducing generation of harmful gas.

Description

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AI Technical Summary

Benefits of technology

This patented technology involves two main technical features: 1) eliminating the need to convey devices like fans or pipes during production while also allowing finely sized materials (small particles), called Lignites) from being added into this process instead of making them themselves. 2) Using external shell heating with an oven loop system that allows for continuous operation at higher temperatures than traditional methods, resulting in better use efficiency of fuel compared to current processes. 3) Improving the yield of semi -cokes by continuously extracting water vapor through condensations inside the chamber before converting it back into liquid form. 4) Reducing wastewater emissions by treating the exhaust gas after conversion.

Problems solved by technology

Lignites have several technical benefits: they contain significant amounts of carbon (C), hydrogen sulfur(H2), nitrogen oxide(NOx)and other elements such as iron (Fe). They represent an abundance resource found around the globe where fossil fuels were developed during World War II. However, their use poses challenges due to poor heat transfer properties caused by volatility at room temperature and difficulty burning heavy coals efficiently without generating harmful emissions when exposed to air over time. This challenge requires effective treatment techniques to improve their recovery potential while maintaining stability under harsh conditions like drought and rainwater.

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