The emissions and environmental impact of PM 10 and trace elements from a modern coal-fired power plant equipped with ESP and wet FGD

Abstract

This study focused on the local environmental impact of a coal-fired power station with a net capacity of 600 MW e. The atmospheric emissions of numerous possible fuel gas components were calculated using the KEMA TRACE MODEL®. The STACKS model was used to calculate annual average immission levels or ground-level concentrations. Also calculated were the levels of wet and dry deposition of plume components in the vicinity of a power station. The calculated immission and deposition levels were then compared with the prevailing background concentrations and deposition levels in the Netherlands. It appears that the concentrations of air pollutants prevailing in the Netherlands are low, and that—with the exception of fine dust and NO 2/NO x —the levels do not exceed or even approach any air quality standards or limits. The present fine dust concentrations are close to the air quality standard, while the standards for NO 2/NO x sometimes are exceeded, mainly as a result of increased traffic emissions. For NO 2, the contribution of power plant emission to background concentrations is less than 2%. The increase in background fine dust concentrations attributable to fly dust ground level concentrations (immissions) is no more than 0.03%. Where the elements present in fly dust are concerned, the increase in the elemental background concentrations is smaller than 1%. The contribution to atmospheric fine dust concentrations in the vicinity of a power station attributable to the formation of secondary aerosols is negligible. The reason is that a distance of approximately 100 km, only about 3% of the gaseous sulphur dioxide and nitrogen oxides present in the plume are converted into secondary aerosols. Total wet and dry fly dust deposition over a 40×40-km area around the power station averages 1.7 mg/m 2/year, with a maximum of 25 mg/m 2/year. Depositions of this will not cause any nuisance. Trace element deposition levels are very low. The increases in background depositions are negligible, varying between 2.5% and 0.01%, depending on the element concerned. The background level of deposition of potentially acidifying substances in the Netherlands has fallen by more than 50% in the last 20 years to a value of about 3100 mol/ha/year in 2000. The main contributors to potential acid deposition are foreign sources (43%) and the agricultural industry (41%). The hypothetical power station was calculated to contribute on average only 15 acid equivalents/year across the area referred to above. This represents barely any increase in the background level of deposition (0.5%).