Pilot-scale air toxics R&D assessment of creosote-treated and PCP-treated wood cofiring for pulverized coal utility boiler applications

This paper presents air toxics emissions test results from a pilot-scale co firing study of pentachlorophenol- (PCP) and creosote-treated woods to prov ide data for pre-permitting requirements for utilities interested in biomas s cofiring as a means of increasing renewable energy while reducing greenho use gases and other emissions for pulverized coal-fired utility boilers. Th ese PCP/creosote-treated wood cofiring tests included a comprehensive asses sment of air toxics, including dioxins, furans, polycyclic aromatic hydroca rbons (PAHs), heavy metals (Hg, Sb, As, Cd, Cr, Co, Pb, Ni and Se), formald ehyde and other volatile organic compounds, HCl, and particulates. This pil ot-scale testing measured 'uncontrolled' emissions from the combustor (upst ream of flue gas cleanup devices) and showed that PCP/creosote-treated wood could be successfully cofired at 10% heat input without increases in air t oxic emissions as compared to a baseline eastern bituminous coal. Air toxic s emissions were typically very low, and often near or below detection limi ts, largely as a result of the good air/fuel mixing and high furnace temper atures associated with pulverized coal combustion. One expected result was an increase in uncontrolled HCl emissions as a result of the higher chlorin e content in the treated woods, although even at 10% cofiring levers, HCl e missions were within the range of other US coals, This paper is presented t o provide independent data that industry, environmental groups, and regulat ors may consider in evaluating the opportunities for treated wood cofiring test burns and commercialization in full-scale coal-fired boilers in an env ironmentally acceptable manner. (C) 2000 Published by Elsevier Science Ltd.