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

Abstract:

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 (NO_X), 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, NO_X, 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.

Keywords::

• power boilers
• emission sources
• fuel consumption
• mitigation options
• fuel exchange
• emission control technologies
• emission reduction

Acknowledgments

Complicated processes, a multiproduct sector, and a complicated modeling framework, such as the UISIS model, could not have been completed without the support and advice of many individuals and organizations. We gratefully acknowledge the following contributions. Dr. Ravi Srivastava, Mrs. Elineth Torres, Dr. Alex Macpherson, Dr. Kelley Spence, and Mr. John Bradfield of the EPA provided many quality assurance checks on the PNP data and modeling equations. Under EPA Contract EP-D-06–118, Andover Technologies developed the technical information on available controls and energy efficiency measures used in the modeling tool to generate results. RTI International assisted with development of PNP boilers documentation under EPA contract EP-W-11–027. Finally, we thank our colleagues at the EPA/ Air Pollution Prevention and Control Division (APPCD) who provided insight and expertise that greatly assisted the research.

Disclosure

Reference herein to any specific processes or services by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the EPA. The views and opinions of authors expressed herein do not necessarily state or reflect those of the EPA and shall not be used for advertising or process endorsement purposes. The example analyses of emission reduction strategies given in this paper are shown for illustrative purposes only and do not reflect any opinions or policies of the EPA. The authors report no other conflicts of interest in this work.