Design of Coal Downdraft Gasifier

• Main Author: Paramaputra, Anthya
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/40784
• Institution: Institut Teknologi Bandung

Indonesia's energy demand increases every year. Those energy demands are sufficed from a variety of sources with a certain percentage of energy called the energy mix. In 2011, the energy mix is dominated by oil at 46.9%. Regarding to the Presidential Regulation No. 5 of 2006, the largest percentage of the energy mix for the 2025 is coal by 33%. In 2011, the Indonesian Ministry of Energy and Mineral Resources stated that Indonesia’s coal resources were up to 105 billion tons. In Blueprint of National Energy Management, one of the efforts to environmentally utilize coal is gasification. Gasification is conversion of carbonaceous fuel in gasses products with a useable heating value. Four processes that occur in gasification are drying, devolatilization, combustion/oxidation, and reduction. The design of the downdraft gasifier’s dimensions could use the empirical curve provided by the Swedish Academy of Engineering Science and also downdraft gasifier comparison review. The main dimensions of the downdraft gasifier is 28 cm reactor’s diameter with 30 cm high pyrolysis zone, 11 cm nozzle height to the throat, 11 mm nozzle’s diameter, 5 nozzles, 10 cm throat’s diameter and 35.5 cm reduction zone height. Gasification process modeling uses Cycle Tempo Release 5.0 software with air as an oxidant, 1 atm operating pressure, 900oC of reaction temperature. Based on the modeling results and the main dimensions of the reactor, the reactor’s capacity is 69.12 Nm3/hr, 0.87 Nm3/cm2-hr hearth load, coal consumption rate is 23.58 kg/hour with 75.13% cold gas efficiency and 69.66% carbon conversion.