Trends in U.S. pulp and paper mill : SO2 and NOx emissions, 1980-1995

Emissions of sulfur dioxide and nitrogen oxides from U.S. pulp and paper mills for 1980, 1985, 1990, and 1995 were estimated from industry-wide surveys. The results showed SO 2 emissions decreased by 45% from 480,000 tons in 1995. Coal and residual oil burning in boilers and combustion of spent kraft pulping liquor in recovery furnaces were the main sources of SO 2 emissions. Reductions resulted from use of lower sulfur coal and residual oil, reduced consumption of residual oil, growing use of SO 2 , controls on boilers and kraft mill thermal oxidized, and increased use of nondirect contact kraft recovery furnaces wiht minimal SO 2 emissions. NO x emissions from pulp and paper mills increased by 15% from 275,000 tons in 1980 to 316,000 tons in 1995 with most increase occurring between 1980 and 1985. Burning of coal, natural gas, and kraft black liquor was the main source of NO x emissions. The reductions in SO 2 emissions and modest increase in NO x emissions from 1980 to 1995 occurred despite an increase of paper and paperboard production of 47% and a 41% rise in kraft pulp production over the same period. In 1995, pulp and paper mill emissions represented approximately 2.5% of the total national SO 2 emissions and 1.5% of the total NO x emissions. Application : results for SO 2 and NO x emissions shon how existing control programs have affected emissions from pulp and paper mills.