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For more than a century, petroleum has been an indispensable part of our lives and the
world's economy.
Usually when we think of petroleum, we focus on the gasoline, jet fuels and diesel needed
to transport us and everyday goods from place to place.
But we don't often realize that there are many other useful products we can derive from
petroleum, creating necessities that we rely on in our day-to-day lives.
Because of their value, petrochemical manufacturers further process these petroleum products to
produce other useful components.
One of the processes is called pyrolysis, or steam cracking. This vital, high temperature
process generates petrochemical building blocks used to create valuable bi-products.
The pyrolysis process takes the crude through a cracking furnace at temperatures up to 1000°C,
where it is "cracked" into these higher value products. Afterwards, the products are separated
into distinct fractions or 'cuts'
The most common products formed from the cuts are Ethylene, Propylene, Butadiene, and a
heavier stream of product called pyrolysis gasoline, also known as Pygas.
Unfortunately, in addition to the desired products, these streams also contain undesirable
side products such as acetylenes, which, if left untreated, can reduce the stability,
quality, and utility of the preferred products
CRI's high performance catalysts, combined with advice on operational and design components
from CRI's affiliates at Shell Global Solutions, can provide unit operators the tools they
need to reliably and selectively remove these side products while preserving the stream's
valuable components.
As an example, let's look at why CRI catalysts are so important for each of these streams.
The treatment of Pygas relies on two hydrotreating stages. The first stage is carried out in
a "trickle-phase" reactor, where the liquid is mixed with hydrogen and the mixture is
dispersed over a catalyst bed. This step is necessary to remove diolefins, particularly
reactive substances that can form gums and cause severe operational problems.
The first stage reactor operation is not always trouble-free. A variety of operational problems
can lead to reactor bed fouling, restricted flow and/or reduced product quality resulting
in unplanned reactor shutdowns.
CRI provides proven solutions to help combat these difficulties.
Efficient, proprietary high dispersion reactor trays, designed by our colleagues at Shell
Global Solutions, provide another impressive solution for first stage hydrotreatment.
The unique tray design provides a full, even feed distribution to maximize the effectiveness
of the CRI catalyst bed.
The result is efficient reactor operation with reduced risk of hot spots, longer cycles
and increased feed capacity.
To address pressure drop build-up, CRI provides a multi-level grading system of inert and
active catalysts.
The top bed uses a catalyst with a shape that creates sufficient void space to trap gummy
substances without restricting flow.
Second and third layer catalysts become increasingly finer in order to further trap smaller particles,
and also to react away gum-forming diolefins in the feed. The result is a proven mitigation
in the rise of pressure drop, increasing cycle length in some cases by more than 50 percent.
The second stage hydrotreating for pygas streams is necessary for removing sulfur and olefins.
This prepares the stream for subsequent extraction of desirable components, specifically BTX--benzene,
toluene, and xylenes.
To minimize potential pressure drop issues in gas phase, CRI provides optimized grading
similar to that found in the first stage. The large inert grading traps solids, and
the smaller active grading removes finer particles and/or reacts away potential gum-forming agents.
CRI provides a variety of second stage catalysts with activities that allow optimization of
reactor performance, preserving the desired BTX components.
These are just some of the solutions CRI offers customers. In addition, CRI provides technical
support through catalyst modeling, reactor performance reviews, and on-site start-up
consultation.
CRI is eager to bring these products, services, and solutions to you. CRI: Delivering Innovation.