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Show for the container glass furnace was estimated at $495,000. These estimates do not include the cost of an oxygen plant; it is assumed that oxygen will be bulk purchased at bulk commodity prices. Operating Costs Each of the four NOx control technologies have operating costs which impact the overall process economics. The main costs associated with operating the various NOx control technologies are: • • • Changes in fuel consumption, and the cost of fuel Cost to maintain the NOx control equipment Cost of oxygen for Oxy-Fuel and OEAS technologies Two of the four technologies impact glass furnace fuel efficiency: gas rebuming and Oxy-Fuel. As shown previously, fuel consumption for gas reburning application is expected to increase by 7 to 8-1/2 percent, depending upon furnace type. Oxy-Fuel on the other hand results in a 15 percent decrease in fuel consumption for regenerative furnaces. The extent to which these changes in fuel consumption impact the operating costs, depends upon the cost of natural gas. Since the cost of natural gas varies by region in the United States, a nominal gas price of $3.50 was used in the operating cost estimates for these technologies, and the impact of price was evaluated by varying it from $1.50 to $5.00 per million Btu. The Oxy-Fuel and OEAS technologies require oxygen. Oxy-Fuel technology uses only oxygen to burn the fuel. In operation of OEAS, 3 to 5 percent of the total oxidant is oxygen. The cost of oxygen is generally reported to be 0.15 $/100 ft3 (40 $/ton), but it can vary as well. For the cost analysis, 40 $/ton was used as the nominal case. NO x Reduction Performance Gas rebuming NOx reductions at each of the model furnaces were estimated based on computational modeling and empirical data. An 80 percent reduction was projected for the container and flat glass furnaces. For OEAS, a 50 percent reduction from 6lb/ton has been show at an Anchor Glass Plant in California. Therefore, a 50 percent removal was used for the model glass furnaces. For Oxy-Fuel, a 90 percent reduction in NOx emissions was used. This value is consistent with recent field data8 and the EPA ACT document. For low NOx burners, data provided by Teichmann indicate that a 40 percent reduction is possible when the initial NOx emission level is 4.5 lb/ton. Cost Comparison Cost effectiveness was calculated by summing the annualized capital cost with the annual operating costs, and dividing by the tons of N02 removed per year - $/ton N02. To annualize capital cost, a capital recovery factor is calculated based on an estimated interest rate and life of the equipment. For this analysis, the interest rate (i) is assumed to be 10 percent. Useful equipment life estimates are based on the EPA ACT document, as well as on comments from industry, and were assumed to be 2 and 8 years for container and flat glass, respectively. Figures 10 through 12 show the calculated cost of control for each NOx control technology for the of estimate flat and container glass model furnaces. Variations in the estimates take into account a -151+30 estimated error in capital costs. Overall, the cost effectiveness of gas reburn, OEAS, and low-NOx burners are similar, but gas rebuming has significantly lower final NOx emissions . 9 |
