EFEKTIVITAS KENAIKAN KONSENTRASI NaOH AKTIVASI HYDROCHAR BATOK KELAPA TERHADAP THERMODINAMIKA PEMBAKARAN CO-FIRING BATU BARA SUB-BITUMINOUS

Abstract

This study is important because biomass co-firing offers a practical strategy to reduce coal-related emissions without major power plant modifications. The research addresses the effect of NaOH activation concentration on the thermodynamic combustion performance of coconut shell hydrochar in a co-firing system. The objective is to analyze changes in mass degradation behavior, Gibbs free energy, enthalpy, and entropy resulting from different NaOH concentrations. An experimental method was applied. Hydrochar was produced through hydrothermal carbonization, chemically activated using 0.5 M and 1 M NaOH, and blended with sub-bituminous coal at a 20:80 ratio. Combustion characteristics were evaluated using Thermogravimetric Analysis combined with the Coats–Redfern model. The results show that higher NaOH concentration lowers the initial degradation temperature and improves combustion thermodynamics. Gibbs free energy decreases, while enthalpy and entropy indicate enhanced reactivity. The study concludes that NaOH activation significantly improves hydrochar suitability for co-firing applications. Future research should examine different blending ratios and industrial-scale implementation.

Keywords: hydrochar, NaOH activation, co-firing, combustion thermodynamics, TGA