Cement Plant Environmental Technology for Achieving High Removal

The U.S. Environmental Protection Agency has adopted revised emission limits to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for the Portland cement manufacturing industry and revised emission limits to the New Source Performance Standards (NSPS) for Portland cement plants. These changes revise the emission limits for specified air pollutants for new and existing cement plants. The NESHAP regulations address the emission limits for materials such as mercury, total hydrocarbons (THCs), hydrochloric acid (HCl), and particulate matter. The NSPS address particulate matter, opacity, nitrogen oxides (NO_x), and sulfur dioxide (SO₂). Herein, a case study is presented in which a novel environmental technology was utilized to help achieve SO₂ removal efficiencies in excess of 97% for a cement plant located in the United States. A slurry scrubber was specified for this application due to its unique ability to achieve high removal efficiencies for SO₂-rich waste gases, using a low-cost reagent. Additional capabilities of this system specific to the cement industry are also discussed, such as hot gas quenching, particulate removal, and resistance to the corrosive, abrasive, and thermally intense environments often found in cement plants.