Emission Characteristics and Control Technology for Stationary Coal-Fueled Diesel Engines

Emissions of primary concern for coal-fueled diesel cogeneration and electric power plants are nitrogen oxides, sulfur dioxide, particulate matter, and aromatic hydrocarbons. In addition, the exhaust particulate size distribution and ash content are relevant to durability of the exhaust valves, turbocharger, and other engine components. This paper summarizes preliminary measurements of “uncontrolled” emissions in the exhaust of a Cooper-Bessemer 33-cm (13-in.) bore, 400 rpm, single-cylinder research engine, operated on “engine-grade” coal-water fuel (0.5 percent ash, 1 percent sulfur, 8 μm mean size coal). Based on these results, we present a preliminary evaluation of emission control options for satisfying hypothetical future emission standards for 2–50 MW power plants. The paper describes coal-diesel component subsystems such as (a) “reburning” for reducing NO_x and hydrocarbon emissions, (b) high- and low-temperature injection of calcium sorbents for SO₂ capture, and (c) high-temperature bag filters for control of fine particles. The expected performance of a conceptual, integrated control system is presented.