Abstract:
Terephthalic acid is a central component in polyester fibres , films, PET bottles, and
other polyester products. It is a raw material for a variety of household products and
clothing, and since much of the plastic and polyester needs of Pakistan are met
through exports, there is an internal need to produce terephthalic acid. Most of the
terephthalic acid now is commercially produced from the oxidation process of
paraxylene.
The project will aim to design a process that produces crude terephthalic acid from
paraxylene by an air oxidation reaction, focusing on obtaining a crude product that can
be further purified. Crude Terephthalic Acid (CTA) produced is about 99.7% pure
containing 4-Carboxybenzaldehyde impurities which weaken the strength of plastics
and fibers and hence must be removed. For mass production, the AMOCO process is
used, which uses a homogenous liquid phase catalyst at set conditions and results in
the highest yield. Our project is centered around producing 100 tons of CTA per day
and maximizing the potential of the plant by optimal design. Moreover, we have
focused on reducing the plant load, increasing efficiency, and making our process more
environmentally friendly and safer. Under assumed economic conditions, this plant is
expected to produce an annual profit of $ 16.3 million and result in a payback period
of 3 years and 6 months.
In our thesis, we will summarize the process design and simulation of a crude
terephthalic acid production plant and describe how our final year project has been
carried out. This will include all relevant stages such as determining the process and
methodology, carrying out an efficient material and energy balance on every
equipment, to designing those equipment and then carrying out an economic analysis
to determine the total costs of the plant. Moreover, a hazard & operability study was
carried out over the plant to account for all possible risks. Lastly, the plant was also
simulated in Aspen Plus and relevant instrumentation for control loops on a reactor
was identified.
