Page 145 - Principles of Catalyst Development

CATALYST PREPARATION 133

6.9.3. Internal Stresses from Phase Changes During Such Processes as
Activation and Regeneration
Mechanical properties of the manufactured catalysts do not necessarily
match those after activation and regeneration. Strengths should not change
too much as the particles weaken due to phase changes during start-up and
use. It is not uncommon for packed beds to shrink considerably when
operation commences. Problems are avoided by following loading and
operating instructions exactly.

6.9.4. External Stresses Caused by Fluid Flow, Pressure Drop, Catalyst
Bed Weight, and Thermal Cycling
The range of strengths that are required are usually found from
experience. A given reactor design will address this problem, but care should
be taken not to violate specifications in selecting a fresh load of catalyst.

6.9.5. Attrition (Particle-Particle Collision Losses)
This is only a problem with moving or fluidized operations. Catalyst
particle strength must match specific requirements. Attrition loss is usually
determined by some standard test, described in Chapter 7.

6.10. LEGAL RESPONSIBILITIES

Catalyst design, preparation, manufacture, and use is a sensitive busi-
ness. Very small changes in composition or steps in the preparation can
result in advantages in processing. There is a very small time scale between
invention and implementation. It is understandable that organizations
engaged in these enterprises are very protective of proprietary information.
Workers in the field must appreciate and honor this. Not only should every
effort be made to maintain security, but information from others should
not be accepted. Discoveries and developments have been jeopardized in
the past because researchers unwillingly or illegally had knowledge of data
from competitors working in the same area. Always exercise secrecy agree-
ments and honor them.
Commercial catalysts are available under the following conditions
described below.

6.10.1. Proprietary
The process is licensed from the vendor and includes the catalyst. The
licensing organization selects the original catalyst and subsequent charges