(691c) Co-Hydrothermal Carbonization of Coal Refuse and Cow Manure Blend

Coal refuse, also known as coal waste and gob, are by products resulted from coal mining. Coal processing plants rejects 30-60% materials from the mined coal during the cleaning procedure and it contains 40-70% energy compared to coal. However, toxic elements (sulfur, heavy metals and ash) present in coal refuse possess serious environmental threat and that is why it is not possible to combust coal refuse without prior treatment. That is why, it is necessary to perform a pre-treatment process to reduce the amount of toxic elements before using coal refuse.

Co-hydrothermal treatment (co-HTC) of coal refuse along with a biomass (e.g. cow manure, pine wood or Miscanthus) can be an efficient option to utilize this huge amount of available fuel resource. Co-HTC is a thermochemical process, where feedstock is treated at high temperature (180-280 °C) and corresponding vapor pressure (5-60 bars). During the process, biomass will provide additional carbon and organic substances to coal refuse and produce final product of similar fuel properties of coal. Previous studies have shown significant decrease of toxic materials when hydrothermal treatment was performed on coal and biomass mixture.

This study will perform co-HTC of coal refuse and cow manure at three different temperatures (180, 230 and 280°C) for 10, 30 and 50 min of residence time for each temperature with a 50-50 (dry wt. basis) coal refuse-biomass ratio. Fuel quality of the product of co-HTC process will be determined by evaluating mass yield, energy content, ultimate analysis and proximate analysis. IC and SEM-EDS analysis of solid product will be performed to analyze the level of toxic compound concentration.