Coal

Abstract

Abstract Coal, a nonrenewable fossil fuel, which has been used since ancient times, is one of the major sources of energy at present as well. Coal use is associated with several operational and environmental problems. Most of the high-grade coals have already been extracted, so coal left for future use is more of low grade with high moisture and ash content. Environmental issues related to coal combustion are multifaceted and are threatening the sustainability of coal use, mostly in power generation and gasification. There are quite efficient technologies that do exist for controlling pollutants such as oxides of nitrogen and sulfur, trace elements, and fine particulate matter. However, one of the serious problems facing the future of coal is emission of carbon dioxide—a greenhouse gas leading to climate change. Coal is still going to be a major player in the global energy spectrum over next 30–40 years and, in particular, for the countries such as India and China. However, the sustainable future of coal depends on mitigating these pollutants and GHG emissions. This chapter reviews the advanced characterization of coal so as to link the coal properties to operational problems such as unburned carbon and ash-related issues. The beneficiation of coal, both physical and chemical, has been included to improve the coal quality in order to reduce these emissions. The environmental issues related to emissions of NOx, SOx, trace elements and fine particulate matter, and postcombustion technologies to reduce these emissions have been presented as well. The utilization of such technologies and installation of pollution control devices can meet stringent regulatory emission limits except GHGs emission. Advanced combustion technologies, such as supercritical, ultrasupercritical boilers, integrated gasification combined cycle, and integrated gasification fuel cell, increase electricity generation efficiency and thereby reduce the GHG emissions per unit of electricity. There are a number of carbon capture technologies, including precombustion, postcombustion, oxy-firing, and chemical looping combustion, those aid to reduce GHG emissions. Current status for carbon capture and storage is also presented in this chapter. The utilization of high-efficiency low-emission technologies, including coal beneficiation, advanced combustion technologies, installation of pollution control measures, and the deployment of carbon capture and storage technologies, can leverage the coal use sustainability.