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Show OPERATION AND CONTROL OF NOx REDUCTION SYSTEMS ~ Gregory P. Crocland Eric Fearon Kinetics Technology Corporation \ p San Dimas, California \I) '(,K 1 ~ C /f /7{1 ~/ ABSTRACT The reduction of NOx emissions from fired heaters can be accomplished by a variety of different techniques 1 • The problem that all these technologies have in common is that they will only reduce NOx consistently as long as proper precautions have been taken to make them controllable and reliable. A major target of any NOx reduction system is its reliability and controllability. This paper points out some of the pitfalls in the design of a NOx reduction system, from both the controls and operational standpoint, and the precautions that can be taken to prevent costly problems in the field. ) 1. INTRODUCTION Many years of development work has been performed in an attempt to supply the industry with NOx reduction technologies that provide consistent NOx reduction. To simply design a system utilizing these available technologies is not enough. An effort has to be made to understand the limitations of these technologies and apply this knowledge to the development of a system that will be both reliable and controllable for many years to come. Implementation of a controllable NOx reduction system for an existing furnace requires that the engineer consider the following: • Evaluation of the present control philosophy • Design a new system around the existing equipment • Perform a Hazard and Operability Study (HAZOP) • Transfer the design philosophy to the end user (operator training) 2. PRESENT CONTROL PHILOSOPHY The evaluation of the existing control philosophy is essential since the fired heaters we are primarily dealing with are being revamped. As such, the plant operators are accustomed to operating the heater in a particular way, therefore it is very important not to alter this present philosophy. In some cases however, the present philosophy may lend itself to some improvements. In this case the NOx reduction project is a perfect time to enhance the controllability of the heater. 1 |