STUDY OF THE UPGRADING OF LOW RANK COAL FROM SOUTH SUMATERA BY USING ENZOL, MOLASSES, AND USED LUBRICATING OIL COATING

• Main Author: Puritza, Yarga
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/43823
• Institution: Institut Teknologi Bandung

Indonesia is known as the second largest coal exporter in the world with total exports reaching 390.6 MT. The use of coal in the country is also expected to increase given the 30000 MW PLN project which the majority of power plants use coal as their main energy source. However, 60% of Indonesia's coal reserves are low rank coal. Low rank coal has several disadvantages such as having a low calorific value, high percent moisture, very easy to absorb water, and very reactive so it can cause spontaneous combustion. The quality of low rank coal can be improved through upgrading methods. One method of coal upgrading is by drying coal that has been mixed with a certain composition of coating at a temperature that exceeds the boiling point of water in a certain duration. Coal samples from South Sumatra are classified into low rank coal. This study began with coal preparation process which are crushing, grinding, and sieving by sieve shaker to obtain coal size fractions which includes -14+35#, -35+42#, and -42+65 #. The coal upgrading experiment begins with mixing the coal with 3 types of coatings which are enzol, molasses, and used lubricating oil, then the coal mixture is dried on oven at the temperature of 107 oC for 45 minutes. This study was done to study the effect of coating type, coating concentration and coal size toward upgraded coal quality parameters. Coal quality parameters include moisture content, calorific value, and moisture readsorption percentage of coal. The results of the proximate analysis of the initial raw coal sample based on ASTM D-3172 standard showed that raw coal sample has high moisture content and moisture readsorption reaching 26.01% and 37.31% (adb) respectively. The results of calorific value measurement by using bomb calorimeter also showed raw coal sample has low calorific value which was 4309.2 kcal/kg (moist mmf). The experimental results indicate that the most optimum coal quality parameters were obtained when coal is mixed with a coating that has high viscosity and calorific value and low moisture content with the highest coating composition in coal whose size ranged at - 35 + 42 mesh. The most optimum results of this coal upgrading experiment were achieved on coal with size fraction ranged at - 35 + 42 mesh mixed with used oil with a concentration of 7% (w/w). This coal sample had low moisture content and moisture readsorption reaching 12.03% and 14.61% (adb) respectively and high GCV which was 5902 kkal/kg (moist mmf).