SO2 emissions history and scrubbing system

The author describes how RMC Lonestar´s Santa Cruz Plant dealt with the problem of sulfur dioxide emissions. He discusses the systematic approach the plant employed to learn about the origin of the SO₂ problem and the experimental projects carried out to collect the data to design a system to control SO₂ emissions. He describes the development of a pilot plant dry scrubber for SO₂ control and the implementation of the ultimate alkaline slurry injection system (ASIS). He also examines the systems effectiveness in controlling SO₂ and its limitations. The ASIS is the only one employed in the cement industry today in the United States for SO₂ control and it is enabling the Santa Cruz Plant to comply with the permitted SO₂ emissions. This experience underscores the importance of sulfides in the raw materials as a source of emissions and the cost effectiveness of hydrated lime slurry addition when moderate SO ₂ reductions are required from the preheater system