New Approach Study on Dry Coal Cleaning System with Two-Stage Corona Electrostatic Processes for High-Sulfur Low-Grade Fine Coals

Chengyuan Liu,Qingyue Wang

doi:10.3390/pr9111915

Abstract

Corona electrostatic separation can remove inorganic materials from coal, reduce coal ash content and sulfur content and improve coal quality, reduce air pollution caused by smoke dust, SOX, and COX. The performance of corona electrostatic separation technology in cleaning a middle ash medium-ash, high-sulfur coal was experimentally investigated. The electrode voltage, drum rotational speed, and feeding speed were tested, whereas other parameters were maintained constant during the experiment. The results indicate that the performance of this technology in cleaning medium-ash, high-sulfur coal can be improved by optimizing the process parameters. The results demonstrate that corona electrostatic separation is effective for the beneficiation of this grade coal. In addition, the efficiency of coal cleaning is significantly improved by adding the second stage beneficiation to clean the middlings out from the first stage beneficiation. In this study, the first stage of beneficiation recovered 38.00% (by weight) of clean coal (ash content below 20%), and the second stage recovered 48.58% (by weight) of clean coal, improving the overall separation efficiency from 0.69 to 1.74. Furthermore, the sulfur content was reduced from 4.71% (raw coal) to 3.53% (clean coal). Our result show that corona electrostatic separation can effectively reject inorganic sulfur from raw coal, and the two-stage separate is also very helpful for coal purification.

Highlights

Coal is a major energy source, accounting for approximately 27% of the world’s total energy consumption [1] and plays an important role in providing energy around the world
Our result show that corona electrostatic separation can effectively reject inorganic sulfur from raw coal, and the two-stage separate is very helpful for coal purification
Coal particle weights less than 1% of that of the feedstock were not included in the analysis

Summary

Introduction

Coal is a major energy source, accounting for approximately 27% of the world’s total energy consumption [1] and plays an important role in providing energy around the world. China is extremely poor in crude oil and natural gas resources and relies heavily on imports of these two energy resources [2,3] Renewable energies, such as solar, wind, nuclear, and hydraulic energies, yet cannot provide stable supplies in large quantities (renewable energy to account for 23% of global energy supply in 2106) [4]. Coal is considered a strategic energy reservoir and has played an irreplaceable role in China for a long time [5]. CO2 and SO2 have important climatic implications [7] and could lead to temperature increases [8]

Methods

Results

Conclusion