Maulana Yusuf, Eddy Ibrahim, Edward Saleh, Moh Rashid Ridho, Iskhaq Iskandar
Background: The intensive utilization of low-grade coal (<5,100 kcal / kg) as a fuel in a steam power plant can lead to intense emission of methane (CH4), whose amount is increasing in the atmosphere. The intensive emissions of CH4 gas will affect the global warming, especially climate change. The chemical reaction between CH4 gas and oxygen (O2) in the combustion of coal will reduce the concentration of oxygen and increase CO2 (carbon dioxide) and H2O (water vapor). A decrease in the oxygen concentration of 2% will increase the concentration of CH4 in the air by 10%. An intensive decrease of oxygen will adversely affect the health of the plants, it can even cause death. Aim and Objectives: The aim of this study is to show the effects of a decrease in oxygen on the increased CH4 emissions from the burning of coal of different types of calories. The characteristics of the coal burning is analogized with the actual conditions occurring in nature which are associated with the environmental health, especially the disruption to the health of plant. Methods: This study was conducted in the laboratory using a range of coal samples from coal of low-calorie to coal of high-calorie. The combustion systems used in this study was a modified fixed-bed coal combustion. The oxygen concentration and CH4 emission were read from multigas detector, and a thermocouple was used to measure the temperature of the combustion of coal. The variables observed in this study were the oxygen concentration (%) and CH4 emission (ppm) of various grades of coals, from a low-calorie coal to a high-calorie coal with codes of BA-59, BA-63, BA-67, BA-76. The data obtained from this study were processed using statistical methods. The data generated were compared to the minimum permissible oxygen in plants, namely by 20%. In addition, a decrease in oxygen concentration can also be proved by chemical reactions occurring between gases of CH4 and oxygen which produces CO2 (carbon dioxide) and H2O (water vapor). Results: Based on the statistical tests comprising of a data normality test, hypothetical test and non-linear regression analysis, a significant correlation between the decrease in oxygen concentration and increased CH4 emissions was obtained. The calculations carried out produced oxygen concentrations and emissions of CH4 from each category of coal from low to high-grade coal respectively as follows: BA-59: 11.8% and 4.8 ppm; BA-63: 15.3% and 1.3 ppm; BA-63: 16.4% and 0.3 ppm; BA-76: 17.2% and 0.1 ppm. While the percentage of oxygen allowed for plant respiration is a minimum of 20%. Conclusion: The combustion of low grade coal for the power plant activity will decrease the concentration of oxygen and increase the CH4 gas emissions in the atmosphere that can damage the health of the plants and it can even cause death. The mitigation of CH4 emission generated by the combustion of low grade coal for power plant can be done by upgrading low-calorie coal so that its characteristics change.
