Survival Prediction
Model
Since 1983, The KIP Company has been involved with products used in
heterogeneous and homogeneous catalytic processing. Since 1989, The KIP
Company has supplied ceramic Catalyst Bed Supports (also called balls,
pellets, or "inerts") used in hydrotreaters, reformers and other
fixed-bed catalytic units in petroleum refining, petrochemical
processing and various chemical reactions.
During the last 20 years, I have seen more than one failure in
a heterogeneous catalyst bed (such as a reformer pretreater or
hydrockracker) which was caused by failure of the so-called 'inert bed
support', not by the catalyst itself.
When Catalyst Bed Supports degrade in heterogeneous catalytic
operations, it splits into shards and/or powders, sometimes in sounding
like small explosions in the unit. One operator reported the sounds
were like someone shooting a shotgun at the unit. The resulting
increase in pressure drop almost always costs more than $0.5 million
per event.
Since 1992, we have been conducting autopsies of Catalyst Bed
Support unloaded from commercial operating units to learn the mechanism
of degradation. Many units experienced no problems during their on-line
time. Some Catalyst Bed Support failures were discovered during on-line
operations, while other failures were only observed when the unit was
turned around.
This study is complicated by the fact that retained fresh samples are
not normally kept by the operating company.
The testing included standard tests by independent laboratories using
ASTM methods. By analyzing this and additional data, The KIP Company
has evolved a survival prediction model for low-alumina Catalyst Bed
Supports. This model is proprietary and is expressed graphically in this chart.
The KIP Company used this model to analyze for a pressure drop problem
in five units in 1998. The model accurately identified which units had
catalyst bed support failures.
The KIP Company is searching for additional samples to continue
confirming its model, and assistance in continuing this work.
The following charts are included in the model:
Attrition
Bulk density
Crush Strength
Pore size distribution
Silica alumina percentages
Secondary chemical percentages
Temperatures of used Catalyst Bed Supports
Pressures of used Catalyst Bed Supports
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Testing Services
October 1994, October 2000
