Analysis of Combustion of a Steam Boiler with Chips and Bark as Fuel

Abstract

PT. Medco is a business entity engaged in managing industrial plantation forests and one of the company’s branches is in South Papua—Merauke. This company manages wood to be processed into raw materials for paper and other purposes. Timber production activities that produce waste in very large volumes, these wastes still have a high calorific value which their utilization will produce fuels that can be used, one of which is as fuel for boilers for power generation. This study uses a qualitative method where research is conducted to obtain the necessary data to then be analyzed again by calculating combustion using the British Thermal Unit (BTU) analysis method. Preliminary data required for qualitative analysis include operational and technical steam boiler data. The fuel used in the combustion process is wood chips and bark obtained from production residue or what can be called waste. The results of the calculation of the combustion process in the 1 × 7 MW steam boiler (PLTU) PT. Medco shows Carbon (C) 34.47%, Hydrogen (H2) 4.22%, Sulfur (S) 0.06%, Oxygen (O2) 30.75%, Nitrogen (N2) 0.22%, Water (H2O) 27.80%, Ash 2.48% and a calorific value of Hight Heating Value (HHV) 9160.8 Btu/lb, Excess water 30% and fuel consumption of 16784 kg/h. The mass flow rate of steam is 35 tons or 66150 lb/h with a combustion gas temperature of 1490 °C and an adiabatic temperature formed in the furnace of 1075 °C. Primary air requirement is 43594.91 kg of air and the secondary air requirement is 18727.24 kg of air. The heat energy that is put into the steam boiler from the results of the combustion process is 98.24 × 106 BTU/h or 28.77204 MW, the heat that is utilized for the process of changing the fluid phase of the liquid in the water pipes along the boiler wall is only 83.038 × 106 BTU/h or 24.31975425 MW. So, it can be concluded that there is an energy loss of 15.2020 × 106 BTU/h or 4.452286 MW.