Widows Creek Unit 8 Wet-Limestone-Scrubber Research Project Environmental Evaluations: Task 6 - Air. Environmental Impact Statement

摘要

This report describes a theoretical analysis of the possible increased frequency of anthropogenic fog and ice and changes in ambient SO sub 2 concentrations due to the operation of the Widows Creek Unit 8 was limestone scrubber. The analysis included three scenarios for reheating the scrubbed gases; low, medium, and high temperatures. Reheating to a higher temperature gives greater plume heights and thus reduces the impact near the plant. Very little impact of anthropogenic ice is predicted under any reheat level. At the worst case (lowest reheat), only 2 percent of the area around the Widows Creek Steam Plant is predicted to be impacted once per year and none of the area is predicted to be impacted twice or more. Anthropogenic fog is predicted to have a low-level impact over a large area (55 percent of the area at one occurrence of fog per year, low reheat) and to have a higher-level impact over a small area (10 percent of the area at 10 occurrences of fog per year, low reheat). It is assumed the scrubber removed 88 percent of the SO sub 2 in the plume. Because of reduced plume rise, however, ambient SO sub 2 concentrations are often not reduced by 88 percent. Under low reheat, for example, nearly 25 percent of the area near Widows Creek Steam Plant is predicted to experience a reduction in annual averaged SO sub 2 concentrations of less than 75 percent. Under medium reheat, however, the area of impact is reduced from 25 percent to less than 2 percent. (ERA citation 08:013751)