Analysis of emission reduction strategies for power boilers in the US pulp and paper industry.

The US pulp and paper (PNP) industry utilizes a variety of fuels to provide energy for process needs, resulting in air emissions of sulfur dioxide (SO2), nitrogen oxides (NOX), particulate matter (PM), and greenhouse gases such as carbon dioxide (CO2). Emissions from this sector have largely declined and continue to decline steadily since the mid-1990s, reflecting changes in fuel types used and their sulfur content, fluctuation in PNP production, increase in the volume of recycling, efficiency gains throughout the sector, and capital investments for compliance with regulations. Because of the above factors, recent market trends favoring the use of natural gas over coal, and more demanding regulatory limits, it is reasonable to expect that air emissions from the sector will continue to decline in the near future. Boilers have been the dominant source of SO2, NOX, PM, and CO2 emissions for the sector. It would, therefore, be of interest to understand how air pollution controls have been applied to date on new, existing, and replaced units, as well as the cost and emission reductions associated with expanding their use throughout the sector. In the work described here, the Universal Industrial Sectors Integrated Solutions (UISIS) model developed by the U.S. Environmental Protection Agency is used to examine the emission reduction potential and cost of controls. This paper briefly characterizes air emissions from boilers operating in the PNP sector and reviews the menu of air pollution control technologies applicable to the sector. Then, after describing the UISIS PNP model, modeling results are presented, in which several illustrative air emission reduction strategies are assessed, including fuel switching, installation of air pollution control equipment, and implementation of energy efficiency measures.