Energy Audit Analysis of Coal Boiler by using Direct and Indirect Methods: Case Study of PT. Pupuk Kalimantan Timur, Indonesia

S. Silviana, Luqman Buchori


World energy consumption is increasing proportional to the rapid advancement of technology. While efforts to supply the ever-growing energy demand were done continuously, increasing the supply for pre-existing industries is expensive and bound by various limitations. Therefore, there is a growing interest in energy efficiency with energy audit analysis plays an important role in discovering energy-saving opportunities. The most potential equipment for energy efficiency in agricultural industry are the boilers of fertilizer factories. PT. Pupuk Kalimantan Timur, Indonesia's largest urea and ammonia producer, uses Circulating Fluidized-Bed Boiler; a very promising subject of energy audit analysis in agriculture industry. Case study using direct and indirect methods was done in order to identify coal efficiency and excessive energy use. Data were collected from primary and secondary sources and analyzed through several stages. Result shows that using medium-rank coal yields higher boiler efficiency. Using direct method, medium-rank coal efficiency is found to be 91.84% and 93.09% compared to using low-rank coal, which is 89.70% and 91.84%. Meanwhile, calculation using indirect method found the efficiency using medium-rank coal is 95.03% and 95.35% compared to using low-rank coal, 93.39% and 93.81%, respectively. This efficiency difference is influenced by coal calorific value, fuel and steam rates, flue gas, fuel factor, specific heat, and air temperature with the correlation between one another described in this study.


Audit; Circulating fluidized-bed; Coal boiler; Efficiency; Energy

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