STUDY OF THE EFFECT OF COAL PRETREATMENT AND FEEDING METHODS ON LOW RANK COAL GASIFICATION PERFORMANCE USING ASPEN PLUS

• Main Author: Pasuria Rumapea, Monika
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69304
• Institution: Institut Teknologi Bandung

Although the contribution of renewable energy (EBT) continues to grow, the role of fossil fuels, including coal, as the main provider of 80% of national energy cannot be replaced in the near future. Currently, the cost of producing electricity from coal is still lower than from NRE and natural gas in Indonesia. But unfortunately, the use of coal is still dominated by direct combustion, which is less environmentally friendly. Converting coal into electrical energy via gasification uses integrated gasification combine cycle (IGCC) technology, so that lower CO2 emissions per unit of energy can be an alternative. The entrained-flow gasifier (EFG) reactor was chosen because it has clean gas and less tar. EFG has two feeding systems, namely dry-feed and slurry-feed. To find out which feeding system is efficient and suitable for Indonesia's low rank coal (LRC), the performance of Indonesia's LRC gasification in both options needs to be studied both by experimental studies and process simulations to optimize the potential utilization of LRC coal in Indonesia. To obtain a slurry with low viscosity and high stability, pretreatment of coal-water slurry (CWS) and coal-water alcohol slurry (CWAS) is carried out. Meanwhile, in the dry-feed system, pretreatment drying (drying) is carried out which requires heat so that the operating temperature can be higher than the slurry-feed and increase the efficiency of carbon conversion. In addition, acid-washing was also carried out to determine the effect of alkali and alkaline earth metal content on the gasification rate. In this study, a series of characterization and gasification experiments were carried out on five samples of low rank coal, namely raw, drying, acid-washing, CWS and CWAS. Coal characterization was carried out using fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), ultimate and proximate analysis and analysis of ash content. While the gasification experiment was carried out using a tube furnace with 10% oxygen gasification agent. The results of the characterization were then used as input to simulate the gasification of the five samples using the Aspen plus software. The results showed that the addition of alcohol to coal-water slurry increased 1% calorific value (daf) from 6.298 to 6.358 kcal/kg. Acid washing can reduce the catalyst components in coal in the form of Na 0.003%, K 0.004%, and Ca 0.929% so that the order of the rate of coal gasification using 10% O2 is drying > CWAS > CWS > raw > acid washing. The drying sample is the most efficient sample in the generating system with a CGE value 74.00% and a thermal power 0.71 MW. The CGE values and thermal power of raw, acid-washing, CWS and CWAS samples were 66.16, respectively; 68.53; 57.38; 70.44% and 0.67; 0.62; 0.55; 0.70 MW.