OCR Text |
Show 2 3 AFRC90 Paper 38 THE DESIGN & INSTALLATION OF A LOW TEMPERATURE CATALYTIC NOx REDUCTION SYSTEM FOR FIRED HEATERS & BOILERS Rene Samson 1 , Frans Goudriaan2 Onno Maaskant1 and Tom Gilmore3 Shell International Chemical Company, The Hague, The Netherlands Shell Research, Amsterdam, The Netherlands KTI Corporation, Monrovia, California, U.S.A. ABSTRACT The catalytiC reduction of nitrogen oxides with ammonia is well established industrial practice. Shell has recently come on the market with a proprietary new denoxing technology that comprises both a novel catalyst and several novel reactor concepts for housing this catalyst. The characteristic features of this technology are described in this paper, with special emphasis on the reactor technology. The design of a reactor used for denoxing the flue gases of a refinery furnace is treated as a special example. - 1.0 INTRODUCTION 1.1 Historical Background Around 1986, researchers working at the Shell Research Laboratories in Amsterdam, The Netherlands, discovered that Shell silica granules impregnated withJitanium and Vanadium oxides have excellent activity as a denoxing catalyst. The initial development of this catalyst has been documented elsewhere (Refs. 1 and 2). As Shell already had a strong position in the manufacture of ultrastrong silica carriers (used, for example, in the Hycon process), this catalyst fitted nicely into the existing portfolio. One of the outstanding features of the Shell denox catalyst in comparison to competing catalysts is that it retains its activity down to very low temperatures. Competitors' catalysts are usually employed in the temperature range between 5500 and 7500 F and seldom below 5000 F. The Shell denox catalyst retains its activity down to 2500 F. In the "conventional" temperature range between 5500 and 6500 F, Shell denox technology is competitive with existing denox technologies. |