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Show 4197299444 CORP. HQ 489 P15 MAR 17 '94 12:13 Applications The test results for the proposed combustion technique indicate that it is possible to achieve extremely low levels of NOx for high temperature processes while using highly preheated air. Use of conventional combustion modification teehniques such as the traditional two stage combustion burner, flue gas recirculation, steam or water injection or the use of excess air cannot achieve these low levels of NOx without sacrificing the process thermal efficiency. This combustion technique is, therefore, ideally suited fpr many high temperatur~ industrial processes where the process temperatures exceed 982·C (1800·F). Examples of such applications are: heating of steel for forging, forming and rolling, melting of ferrou~ scrap and other ,metals, crude oil and petroleum heaters, etc. In each case the heating system incorporates .a rich combustion zone in which heat is transferred to the load or work and the flue gases are cooled to an appropriate temperature before additional air is mixed with the , \ flue products to complete the combustion of rich gases. ,\ Combustion of rich products of combustion may use more than one reburning step, if required. In addition to a substantial reduction of NOx the system offers major economic benefits when rich products of combustion (reducing atmosphere) generated in the first step are used to prevent oxidation in the form of scaling or slagging of ferrous metals. The MicroNOx burner developed under this program is capable of producing a gas with a composition that is reducinq to steel and iron. Slabs, billets, and bars heated with these burners will not form scale! Economic viability of emerging metal production techniques such as thin slab and thin strip casting combined with continuous rolling can be greatly enhanced by· use of NO-NOx and scale free combustion technologies. The economic benefits of avoiding metal losses and increasing metal yields can far exceed the entire energy cost for melting or reheating of ferrous alloys. A preliminary analysis of a scale 'free reheating furnace using the proposed combustion technique can reduce the scale loss from 2% to less than 0.1%. It is estimated tkat the cost of a furnace designed to be used as a scale free heating furnace may be less than 10% higher than a conventional furnace design. The economic benefit of scale free heating can potentially pay for a new furnace or melter in a relatively short time, in many cases less than twelve months. Major improvements in thermal efficiency, lower fuel costs, dramatic reductions in NOx emissions, and major economic advantages due to lower metal losses can be implemented by , \ |