STUDY OF THE EFFECT OF COFFEE GROUND ADDITION ON CO-GASIFICATION PERFORMANCE WITH COAL USING AIR

• Main Author: Lukman Hakim, Muamar
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/70142
• Institution: Institut Teknologi Bandung

The world's electricity demand continues to increase, while the source of electricity is still dominated by up to 36,7% by coal-fired power plants with emission of 1 kg CO2/kWh. Various efforts have been made to reduce these emissions, one of which is through Integrated Gasification Combine Cycle (IGCC) technology. IGCC can produce electricity with emissions of 0,75 kg CO2/kWh and can process biomass feed. The addition of biomass can provide a synergistic effect by increasing gasification reactivity and syngas yield. However, research on the co-gasification of coal with coffee grounds is still limited. With production reaching 742 thousand tons per year in Indonesia, coffee is a potential source of biomass for further research. Therefore, it is necessary to study the effect of adding coffee grounds on gasification reactivity and the composition of the gas produced during cogasification with coal. In addition to experiments, simulations were also carried out using the Factsage software. In this study, a series of characterization and co-gasification experiments were carried out by varying the ratio of coffee grounds to feed in weight percent (w/w), namely K-0, K-25, K-50, K-75, and K-100. The ultimate, proximate, ash component, and calorific value analysis experiments were only carried out on coal samples (K-0) and coffee grounds (K-100), while for other samples, data were calculated based on the weighted average ratio. The ultimate analysis results are then used as input for the Factsage simulation. The co-gasification experiment was carried out in a horizontal tube furnace filled with 240 mL/min of N2 and 60 mL/min of O2, with a temperature of 900°C, a heating rate of 10°C/min, and an elimination time of 15 minutes. Syngas was then analyzed using gas chromatography, while char was analyzed using Fourier-transform infrared spectroscopy (FTIR) and X-ray Diffraction (XRD). A thermogravimetric analysis (TGA) was also performed for the thermal sample characterization. The experimental results show that adding coffee grounds can increase the gasification rate in the order K-50> K-75>K-100> K-25> K-0. The addition of coffee grounds at a K-75 ratio can increase CO gas yield up to 3,3 times compared to K-0 from 14,1% to 46,6% because more charcoal reacts to become gas. In the K- 75 sample, the CO gas yield value was higher, namely 46.6%, while the calculated CO yield value was 44,8%. This shows that there is a synergy between alkalinealkaline earth compounds which can catalyze the C-O and C-OH bonds resulting from the pyrolysis of volatile matter in coffee grounds, which increases the active sites on the char surface.