Effect of reaction conditions in hydrothermal carbonization (HTC) of cellulose from cotton waste / Mohamad Afiq Tahir

Nowadays, the amount of textile wastes is increased and most of the waste discarded. Textile wastes can be converted into biomass which is a renewable energy source that may be utilized to replace fossil fuels. Hydrothermal carbonization (HTC) is a thermochemical process in which organic wastes such as rubbish, biosolids, agricultural waste, and organic waste from industrial operations are treated in an aqueous environment to produce hydrochar, a solid fuel. Zn catalyst active site in ZnCTW hydrothermal carbonization was observed at different reaction temperatures and residence times to produce high energy density hydrochars. There is limited information about the ZnCh acting as the catalyst for the HTC process. Reaction temperature at 190°C, 200°C, 210°C, and 220°C and residence time at 1, 2, 3, and 4h were used in the procedure to analyze the changes. Besides, the characteristics of physicochemical properties of hydrochars at different reaction temperatures and residence times were determined in terms of proximate analysis, ultimate analysis, and energy density. Cotton textiles wastes (CTW) was used as the feedstocks while ZnCh as the catalyst. ZnCh was mixed with CTW for the synthesis of ZnCTW in 100 ml deionized water. HTC process was performed in the 100 mL Parr Batch Reactor at different reaction temperatures at 190°C, 200°C, 210°C, and 220°C, and residence time at 1, 2, 3,4h. For the characterization of hydrochars, a thermogravimetric analyzer was used to determine the proximate analysis. The characteristics that have been observed for proximate analysis are volatile matter, moisture content, and fixed carbon content. Carbon, hydrogen, nitrogen, and sulfur were analyzed via the ultimate analysis by using a CHNS analyzer. Mass and energy yield and HHV were calculated for the energy density. As a result, the volatile matter for the hydrochar decreased slightly until it reached 41.02% when the reaction temperature and residence time increase while fixed carbon content had the opposite behavior. The HHV was increased up to 24.83% with reaction temperature and residence time since the carbon elements in the hydrochar increased. Even though the energy yield was higher than the mass yield, the energy yield shows the same trend as the mass yield. In total, the high performance of sustainable solid fuels will have better energy densification and rich in carbon content.