Page 61 - Principles of Catalyst Development
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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.