Abstract:
In this project, we have performed the multi-objective optimization of the H2S stripping
operation to reduce the reflux rate while ensuring zero H2S in the final diesel product.
The diesel coming from the heavy crude unit has many impurities and one of those is
sulphur. It is important to convert that sulfur to Hydrogen sulfide and then remove it using
reboiler stripping. The conversion of sulfur to hydrogen sulfide takes place in a reactor in
the presence of catalyst.
Hydrogen sulfide needs to be removed from diesel because it is devastating for the
environment. In the presence of water, it forms sulfuric acid which causes corrosion to the
equipment and can cause skin or eyes burn on contact. Hydrogen sulfide causes blockage of
active sites of the catalysts and thus shortens the life of catalyst and decreases its efficiency.
The amount of sulphur content in diesel is denoted by a Euro Emission Standard. The
higher the Euro number will be, the lower the amount of sulfur will be in the diesel. In
Pakistan, currently Euro- II standard diesel is being made, which means that the content of
sulfur is higher in the diesel in Pakistan.
Furthermore, there was a keen focus on improving the economic aspects of this process.
The optimization and design of a stripping process involves the selection of a configuration
and operating conditions to minimize total operating cost and the amount of hydrogen
sulfide in the final product
