Co-hydrothermal carbonization of lignite–poplar wood sawdust blend

High humidity, high ash content and low heating values are the major disadvantages of using lignite without ant pretreatment. High moisture content and low energy density make some of the biomass resources disadvantages in direct energy production. In this thesis, the main aims to reduce the disadvantages of both sources and obtain fuel with different structural/physical properties by hydrothermal pretreatment. Hydrothermal pretreatment is a thermochemical process, which proceeds in the presence of water under pressure and at temperatures between 180 and 280 °C, while taking advantage of the inherent properties of water under critical conditions. In this study, the behaviour of three different coal and poplar wood sawdust produced in Turkey under hydrothermal conditions was examined. After hydrothermal pretreatment, the heating values of all samples increased. As a result of the hydrothermal pretreatment, coal was determined in accordance with the process conditions with the highest heating value of poplar wood sawdust and 50% by weight of biomass-coal blend were obtained. The blend was subject to hydrothermal pretreatment according to the appropriate process conditions (90 min, 230 °C). Also, the heating value of hydrothermally treated blend is 15.4% higher than the heating value of the raw blend. The hydrothermally pretreated lignite-wood sawdust blend had 12.6% less ash compared to the blend of individually hydrothermally treated wood sawdust and lignite (50% by weight). The concentrations of the emission products of the blend enabled the poplar wood sawdust forming the blend benefit from the low ash content. In addition, it has been observed that the ignition temperature of the hydrothermally treated blend, between the raw materials that make up.