Industrial Hydrodesulphurization Lab Report

In an industrial hydrodesulphurization unit, such as in a refinery, the hydrodesulphurization reaction takes place in a fixed-bed reactor at elevated temperatures ranging from 300 to 400 °C and elevated pressures ranging from 30 to 130 atmospheres of absolute pressure, typically in the presence of a catalyst consisting of an alumina base impregnated with cobalt and molybdenum (usually called a CoMo catalyst).
• Occasionally, a combination of nickel and molybdenum (called NiMo) is used, in addition to the CoMo catalyst, for specific difficult-to-treat feed stocks, such as those containing a high level of chemically bound nitrogen.

• The image below is a schematic depiction of the equipment and the process flow streams in a typical refinery
In addition to the dearomatization, another apparent advantage of this design approach is to achieve "ultra-low" levels of sulfur removal from diesel fuel - potentially well below 5 ppmw. Such low levels of sulfur removal would not only exceed recently announced U.S. Environmental Protection Agency (EPA) sulfur regulations for 2006, but would also meet

even more stringent diesel fuel sulfur limitations currently anticipated in other major jurisdictions around the world.

The Cetane Index of the diesel product is expected to improve by 8 to 10 points, and perhaps more for highly paraffinic gas oil feedstock cuts.

The total hydrogen consumption is in the range of 700-900 scf/b of feed, depending on sulfur, aromatics, and olefins content of the feedstock.

The technology is licensed by HaldorTopsoe and has been recently demonstrated by San Joaquin Refining in Bakersfield California, where a 3,000 bpsd aromatic saturation unit is in operation.Is
Catalyst systems with dual noble metal function have been developed that are more tolerant of much higher levels of sulfur than standard platinum catalysts. These catalysts feature outstanding capabilities for upgrading of middle distillate cuts, converting sulfur to ppm level, reducing nitrogen to non-detectable levels and dropping total aromatics from 40% to less than 5%. Consequently, the multi-functional ASAT catalysts is the first choice when it comes to converting light cycle oil (LCO) to “sulfur-free” diesel fuel in a single-stage process

2.2 Recent trends in Diesel process technology:
Research and development in diesel process technology is contributing towards energy conservation and pollution control. Limited energy sources and statutory demands for environment protection have reflected in the development of new diesel processes.

2.3. Stripping process:
Stripping works on the basis of mass transfer. The idea is to make the conditions favorable for the component, A, in the liquid phase to transfer to the vapor phase. This involves a gas–liquid interface that A must cross. The total amount of A that has moved across this boundary can be defined as the flux of A,