STUDY OF THE EFFECT OF PYROLYSIS PARAMETERS ON LIGNITE PYROLYSIS PRODUCTS’ CHARACTERISTIC: CRITICAL REVIEW

• Main Author: Ammarsetya Nugeraha, Rakha
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/68641
• Institution: Institut Teknologi Bandung

Indonesia has total coal reserves of 37.52 billion tons as of June 2021, with 36% of its reserves categorized as low-calorie coal, including lignite, whose utilization in Indonesia is still limited to direct combustion as fuel for steam power plants. One alternative to the use of lignite is coal pyrolysis which produces char, tar, and gas products. The high volatile matter content in lignite makes its pyrolysis produce more tar and gas, leaving char with a higher calorific value (CV). The main parameters that affect the characteristics of the pyrolysis product are pyrolysis temperature, particle size, heating rate. Many researches on the pyrolysis of lignite have been carried out, but due to the limited range of variables used in those studies, the heterogeneous nature of coal, and the large variety of operating variables used, causes differences of opinion regarding the effect of pyrolysis parameters on product characteristics. Therefore, a review is needed to explain the effect of the lignite pyrolysis parameters in a wider range to determine the optimum parameters of each product. This review begins with the collection of literature on international publication sites and books related to the lignite pyrolysis process which discusses the effect of pyrolysis temperature, particle size, and heating rate on the characteristics of the product. Then carried out data collection, data processing, and visualization in the form of graphs. The results of data processing are then discussed and compared if there are differences in conclusions between the literature. The results of the review showed that increasing the pyrolysis temperature would decrease the char yield, with the highest GCV of char obtained at 600°C to 30.53 MJ/kg with char yield in the range of 42.41-52.68%. Tar yield continued to increase until it reached its peak at a pyrolysis temperature of 500-600°C in the range of 2.4-11.2%. The gas yield also increased with the highest gas GCV obtained at 900°C to 18.8 MJ/Nm3 with a gas yield up to 29.9%. Increasing the particle size will increase the char yield and gas yield, as well as lower the tar yield. In the particle size fraction of 6-10 mm, the highest char yield was obtained in the range of 72.18-89.4% and the highest gas yield was up to 9.48%. Meanwhile, in the 0.08-1.25 mm size fraction, the highest tar yield was obtained up to 15.5%. Increasing the heating rate will reduce char yield, lower tar yield, and gas yield. At a heating rate of 0.05°C/s, a char yield of up to 85.5% was obtained. At a heating rate of 1000°C/s, the tar yield is up to 22.63%, and at 5700°C/s, the gas yield is up to 35.41%. The critical size was found to have a significant effect on the resulting tar yield.