Hydrocarbon Engineering - August 2019

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August 2019 35 HYDROCARBON
ENGINEERING
In order to meet an ever-growing product demand and
remain competitive, downstream oil and gas companies
are always on the lookout for technologies that can
further improve mass transfer capacity, throughput and
flexibility. When valve trays are required for gas-liquid
distillation processes, their design plays a key role in
determining what processing plants can achieve. Therefore,
it is important to choose a mass transfer technology with
the highest capabilities.
How to decide
Movable valve trays are well-suited for fractionating columns
with a wide and fluctuating flow range. When the vapour rate
is low, some of the movable valve units will close, thus
minimising their tendency to weep. When the vapour loads
increase, more valves will open to ensure a more uniform
vapour distribution and minimise the risk of entrainment.
Mass transfer component manufacturers can further
improve the capabilities of these trays by optimising the
design and examining how each detail affects overall
process productivity and flexibility. It is important to select
a tray technology specialist that carries out extensive
research and developmental work together with
computational fluid dynamics (CFD) simulations. These give
an insight into how the valve design influences fluid flow
regimes and dynamics on the tray, during the product
development phase. As a result, by conducting these
studies, manufacturers can optimise the valve design to
deliver high-performance solutions.
A key aspect that needs to be taken into account during
the development of valve products is ensuring the valves
are able to handle high vapour loads before the onset of
entrainment. In addition, the valves should direct the
vapour flow closer to the tray floor, to maximise the
ChewPeng Ang, Sulzer Chemtech,
Singapore, reviews the requirements
and properties that petrochemical
and chemical industries look for
when selecting valve trays for their
distillation processes.