EFFECT OF PARTICLE SIZE, DRYING DURATION AND DRYING METHOD IN UPGRADING PROCESS OF LOW RANK COAL USING WASTE OIL

• Main Author: Amroe, Fadhillah
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/49088
• Institution: Institut Teknologi Bandung

Coal is well known as a natural energy resource and readily available energy resource, which has contributed to energy production worldwide. Indonesia is amongst the few countries in the world which have a large resource and reserve of coal, as much as 125.177 billion tons and 24.349 billion tons respectively. Unfortunately, almost 65% of the resources are categorized as Low-Rank Coal. This type of coal has a low calorific value, high moisture content, and high risk of spontaneous combustion. Upgrading by drying of coal usually conducted to reduce the moisture content of the coal, but those methods are only useful if coal is to be used in a short period, as moisture in the air could readsorbed into the coal. In order to be useful for a longer period, further treatment is also necessary. One of the methods for this is by upgrading the coal using coating. This method can stabilize the coal so it will reduce the risk of spontaneous combustion when in storage and also reduce transporting cost if it is to be used in other places. In this research work, upgrading of coal received from Lahat Region, South Sumatra through oil coating with waste oil was studied. Proximate analysis of raw coal sample was conducted using an oven and furnace. A calorific value test was also conducted using Parr Adiabatic Calorimeter. A series of coal upgrading experiments have been carried out to study the effect of the particle size fraction, drying duration and drying method on the moisture content, calorific value and the moisture re-adsorption nature of coal. Upgrading was studied at an oven temperature of 107°C, coating of 5 wt% and a sample weight of 7 grams. Moisture content was determined using an oven by recording the change of sample mass. Calorific value was determined using Parr Adiabatic Calorimeter. Moisture re-adsorption nature of the coal was determined by carrying out a drying test in an atmospheric environment for 72 hours. Based on research results, the lowest moisture content of 7.16% and the highest calorific value of 4722.02 cal/g (adb) obtained from the experiment with a coal particle size of -35+42 mesh, drying duration of 75 minutes and direct drying method. Moisture content increases with smaller particle sizes due to agglomerating coal with the oil coating. The calorific value increases with longer drying duration, but moisture content decreases significantly only up to 60 minutes drying duration. Different optimum conditions of drying duration were achieved with different particle size to obtain the weakest moisture readsorption nature of coal. The direct drying method is a better choice for lower moisture content and weaker moisture readsorption nature of coal. On the other hand, the interval drying method is a better choice for the higher calorific value of coal.