A Comprehensive Assessment of Clean Coal Fuels for Residential Use to Replace Bituminous Raw Coal

Abstract

Residential coal combustion is a major source of air pollution in developing countries, including China. Indeed, precisely measuring the real-time emission of major air pollutants is often challenging and can hardly be repeated at a lab-scale. In this study, for the first time, two clean coals initiated from raw bituminous coal were burned for real-time estimation of air pollution characteristics and their thermal efficiencies in different stoves. Moreover, thermodynamic equilibrium simulations were investigated for slagging parameters using Factsage 7.1 at reaction temperature 800~1600 °C. Results revealed that the firepower of clean coals (Briquetted coal and Semi-coke) was much higher (2.2 kW and 2.1 kW) than raw coal (1.8 kW) in a traditional stove. However, the thermal efficiencies were remarkably increased (13.3% and 13.5%) in an improved stove for briquetted coal and semi-coke, respectively. The emission of major air pollutants including carbon monoxide (CO), sulfur dioxide (SO2), particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), non-methane hydrocarbons (NMHCs) from both coal and semi-coke was significantly reduced. Thermodynamic equilibrium calculations indicate that briquetted coal is not susceptible to slagging under the reaction conditions in the household stove. The current study provides guidance for the selection of alternative and efficient clean coal fuels in rural areas for household purposes coupled with public health and safety.