Simulation of Hydrothermal Carbonization for Producing Biofuels from Water Hyacinth and Sewage Sludge
摘要
In addressing the energy crisis of today, hydrothermal carbonization (HTC) is a promising method for converting low-grade biomass into biofuel. In the presence of water at elevated temperatures and pressures, this process increases the heating value (HHV) and carbon content while reducing the O/C and H/C ratios. In this article, a model is created using Aspen Plus® to simulate experimental data found in the literature and find an optimum temperature that is suitable for the hydrothermal carbonization process. Two materials, such as water hyacinth and sludge, are studied. The values of proximate and ultimate analysis obtained from literature is used in this study. The simulation is run at seven different temperatures for water hyacinth, ranging from 180 °C to 350 °C, and five different temperatures for sewage sludge, ranging from 180 °C to 300 °C. The temperature is kept at this limit since the enthalpy flow for water hyacinth remains unchanged after 300 °C, and for sludge, the enthalpy flow remains unchanged after 270 °C. Simulations assuming 100% energy recovery efficiency show HHV increases with increased temperature, while O/C and H/C ratios decrease. The percentage of carbon content of HTC products surpasses that of raw materials. A comparison between the simulation results of HHV with published articles shows that the results of the simulations corroborate with literature. For water hyacinth, HHV from simulation is 30.28 MJ/kg, whereas HHV in the literature is 27.2 MJ/kg at 300 °C. For sludge, HHV from simulation is 17.565 MJ/kg, whereas HHV in literature is 16.41 MJ/kg at 270°CC. Additionally, water hyacinth exhibits nearly doubled HHV post-HTC, indicating superior biofuel potential compared to sludge.
Graphical Abstract