An Assessment of Black Liquor Gasification Combined Cycles: Part B — Emission, Costs and Macro-Benefits

Abstract

This paper and its companion (Consonni et al., 2004) summarize the results of a major study (Larson, et al., 2003) that assessed performances, emissions, costs and overall benefits of black liquor gasification combined cycle (BLGCC) technology for the U.S. kraft pulp and paper industry. This paper presents analysis and estimates of the potential mill-level air emissions and financial performance of future commercial BLGCC systems described in technical detail in the companion paper. Also, potential regional and national impacts on energy consumption and emissions are estimated under different future BLGCC market penetration scenarios. Emission estimates for SO2, NOx, CO, volatile organic carbon (VOCs), particulate matter, total reduced sulfur (TRS) and CO2 are developed based on detailed quantitative data for Tomlinson furnaces and on extrapolation of gas turbine emissions and other relevant data for BLGCC systems. Prospective economics for a hypothetical representative mill in the Southeastern U.S. are assessed by assuming that an investment would be made in a new power/recovery system to replace an existing Tomlinson system that has reached the end of its working life. Key inputs to the financial analysis include the mass/energy balances shown in the companion paper and engineering cost estimates for each power/recovery system that were developed by two outside engineering firms. Because the overall objective of the study was to examine the long-term commercial potential for BLGCC, the capital cost estimates were based on assumed “Nth plant” levels of technology maturity and operational reliability. Widespread commercial implementation of BLGCC systems in the United States would enable significant energy savings for the country as a whole. Significant reductions in emissions of criteria pollutants and greenhouse gases could also be achieved, especially in the Southeastern United States, where two-thirds of U.S. kraft pulp mills are located. Relative to state-of-the-art Tomlinson systems, financial returns on investment are attractive without explicit valuation of environmental benefits. With monetary valuation of such benefits, the financial returns are very attractive.