| OCR Text |
Show Two principle observations can be made from these figures regarding the lime-urea economics. First, the technology represents a cost effective approach for achieving a broad range of pollutant emissions reductions. As shown in Figure 6, the capital cost associated with 60% emissions reductions is almost one-third that associated with SCR, and is directly comparable with coal-reburning on a cyclone boiler. Second, the levellzed costs of the lime-urea technology are competitive with all other technologies examined for a given level of emissions reductions. The principle difference In levelized costs between coal reburnlng and lime-urea hydrate is a direct reflection of the sorbent cost with all other costs being roughly the same. Overall, the lime-urea hydrate technology provides a means for minimizing up front capital expenditures. When combined with low NOx burners, the lime-urea hydrate technology can also provide emissions reductions on the order of SCR. SUMMARY Based on the foregoing economic assessment, the lime-urea hydrate technology has been found to be a cost effective approach for the reduction of NOx emissions. By virtue of the relative low capital cost associated with the lime-urea hydrate technology, as well as its inherent flexibility with respect to achievable emissions reductions, the technology can meet a broad range of applications which include: 1) a primary pollutant control technology for substantial reductions of NOx' 2) a trimming technology for maintaining compliance with NOx during peak usage periods of a unit, or 3) a backup pollutant control system for maintaining compliance during breakdowns of primary pollution control equipment. No significant cost impacts, beyond the added cost of the urea itself, were found to be associated with the production of the lime-urea hydrate. The current price level of urea was also evaluated and found to not be sensitive to any increased demand from the utility industry. It should be noted that equivalent transportation costs of 100 miles by truck and 400 miles by rail were incorporated in the lime-urea hydrate cost. Although off-site hydration was assumed for the economic assessment, levelized costs could be reduced significantly should on-site hydration prove to be a viable alternative for a given site, or if 30-day storage requirements could be reduced. A comparison of the economics with alternative technologies demonstrated that the lime-urea hydrate approach is cost effective. Due to its variable cost orientation, the lime-urea hydrate exhibits low capital costs relative to selective catalytic reduction. Also, by combining the lime-urea hydrate technology with low NOx burners, comparable NOx emission reductions to SCR can be achieved. -18- |
