The newest boiler at the mill (1996) is an oil-fired, auxiliary back-up boiler used to supplement steam supply during maintenance downs or other situations when the mill needs a little extra steam. It has a 245 mmBtu/hr heat input capacity, burns recycled fuel oil (RFO) and typically operates 25-50% of the time.
There is no pollution control equipment on the package boiler. Back when the boiler was first permitted, the DOE agreed with PTPC’s assessment that any control beyond “good combustion practices” was cost prohibitive. That includes the burning of a cleaner fuel.
Even so, largely because of its smaller size and intermittent operation, the emissions from the package boiler are only about a third of that from Power Boiler #10. In order of tonnage released, the primary emissions are sulfur dioxide (SO2), nitrous oxides (NOx), particulates (PM) and carbon monoxide (CO).
PCHB Package Boiler Appeal Findings of Fact: http://www.eho.wa.gov/searchdocuments/1999%20Archive/pchb%2098-077%20final.htm