Page 61 - Principles of Catalyst Development
P. 61

48                                                        CHAPTER  3
           problems  always  emerge  at  this  stage.  For  example,  a  need  for  increased
           activity or selectivity may have been successfully treated, but the exposure
           to  real  feeds  or  process  conditions  indicates  serious  deactivation.  A  new
           cycle  of design  then  evolves as this  new threat is  considered.



           3.8.  PROCESS  DESIGN

                The catalyst development is now ready for incorporation into the overall
           process design, but the story seldom stops there. After a period of long-term
           commerical usage, the catalyst may return with a different need encountered,
           and a  new  round  of research,  design, testing,  and  piloting begins.  Loss  of
           potassium in high-pressure steam reforming is an example. It was discovered
           that  potassium,  added  to  decrease  carbon  fouling  in  naphtha  reforming,
           volatilizes too readily from the catalyst. (49) To counter this, catalyst designers
           incorporated an appropriate amount of an isoluble potassium silicate com-
           pound,  which  is  only slowly  hydrolyzed  and  so  maintains  effective  levels
           of volatile  alkali  at  all  times.  This  innovative  "time  release  capsule"  was
           exactly  the  medicine  required to  extend  catalyst life.
                In  the following chapters, the background to all  of these steps is  given
           in  detail.  The  reader should  at  all  times  consider each  area in  perspective
           with  the  integrated  development.  Never  forget  the  objective:  to  solve  a
           process  need  with  efficiency and  economy  in  a  reasonable  time.
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