(756f) Rapid Process Development: Propane to Propylene Process

Most strategic product and process-development decisions are
made very early in the life of a project, at which stage detailed data on
reaction kinetics, phase behavior, chemical properties, etc., are incomplete or
unknown, and investment decisions must be made based on mostly qualitative and
some quantitative information obtained during the discovery phase. In addition,
there is increasing pressure to reduce the development time for new products and
processes.

Process development is usually performed in an evolutionary
way, in which the process flowsheet is developed based on experience and proven
best practice rather than on a systematic framework for generating process
alternatives. Although this approach yields useful designs quickly and
reliably, it does not promote the use of novel technologies or processes, nor
does it allow for the comparison of alternative designs. As a result,
innovative processes with significant economic advantages are often not
explored or incorrectly rejected.

This talk will describe a rapid process development
methodology that utilizes synergistic contributions from Chemical Engineers,
Chemists and Material Scientists to systematically develop and evaluate new
processes. The methodology combines chemistry experiments, process synthesis
(hierarchical design procedure, residue curve maps, pinch analysis, etc.),
modeling and simulation (Aspen Plus, etc.) and economic analysis to synthesize
and rank process alternatives, steer the experimental and process development
programs, identify technology risks and mitigation strategies, develop
intellectual property, and aid in investment decisions.  The end results are frequently
innovative and economically competitive processes developed in an efficient and
cost effective manner.  The methodology is illustrated using the development of
a new on-purpose process for the production of high purity (polymer grade)
propylene using propane as the feedstock.

Propylene is one of largest commodity chemicals in the world,
with an annual worldwide demand of ~ 70 million metric tons, which is projected
to grow at over 6% per year.  Propylene is primarily produced (~94%) as a
co-product of naphtha cracking (ethylene is the primary product) and FCC units
in refineries (gasoline is the primary product).  As ethylene manufactures
switch feedstock from naphtha to ethane (due to the availability of large
quantities of low cost natural gas liquids), combined with a reduced gasoline
demand, co-production will not be able to satisfy the growing demand for
propylene.  It is estimated that by 2020, ~ 20% of propylene demand will have
to be satisfied by other on-purpose technologies.  This shortfall in supply,
coupled with the availability of inexpensive propane from shale gas, has
resulted in significant interest in the manufacture of on-purpose propylene
from propane.  The only commercially available technology for achieving this is
propane dehydrogenation (PDH) from UOP (Oleflex) and Lummus Technology (CATOFIN).

Using the rapid design methodology, GRT Inc. has developed
an innovative new technology for the production of high purity (polymer grade)
propylene using propane as the feedstock. Based on capital and operating cost
estimation performed by a top-tier Engineering Company,  compared to current
state of the art propane dehydrogenation (PDH) processes, the GRT process has a
number of important advantages:

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Highly selective production of propylene; no significant
byproducts

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Simple energy efficient separations; no propane/propylene
splitter or cold box

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Minimal coke formation ? infrequent de-coking and simple reactor
design

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No refrigeration

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~ 9% improvement in feedstock conversion efficiency

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21% reduction in energy requirements

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82% reduction in CO₂ emission

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30% reduction in capital cost (450 kta plant)

These advantages result in a total cost of production
advantage of ~ $200 per metric ton of propylene.