Advanced Program K4
Group 7
Bui Trung Duc
Nguyen Tran Hoan
Pham Anh Tu
Bui Tat Dat
Le Duc Huy
Technology for deep desulfurization
Content
1. Existence of sulfur in fuel
Sulfur compounds in oil is the main reasons causing the corrosion of equipment and pollution because of eliminating sulfide to environment
In order to protect public health an environment, Viet Nam will have to apply the deep desulfurization in fuel reduction, especially when Dung Quat oil refinery use mainly materials from Mideast. Therefore, the research of deep desulfurization is urgently required for the development of industry oil refinery- petrochemical Viet Nam’s future
2. Hydrodesulfurization(HDS)
HDS is a catalytic chemical process widely used to remove sulfur (S) from natural gas and from refined petroleum products, such as gasoline or petrol, jet fuel, kerosene, diesel fuel, and fuel oils
3. Advanced Technologies in deep HDS
3.1 Catalytic distillation
Catalytic distillation is a branch of reactive distillation which combines the processes of distillation and catalysis to selectively separate mixtures within solutions.
Its main function is to maximize the yield of catalytic organic reactions, such as the refining of gasoline
3.1.1. Feedstock and Catalyst
Feedstock: FCC naphtha
Catalyst:
- The majority of the catalysts are powdered acids, bases(NaOH…), metal oxides(MoS2), or metal halides
-The catalysts used for catalytic distillation are composed of different substances and packed onto varying objects
3.1.2. Processes
FCC naphtha put onto the distillation column reactor; light naphtha go up because it’s slight, heavy naphtah go down because it’s weighty
Hydro put onto from the bottom of the column
In condenser, light naphtha, hydro and hydro sulfid get in. At the wire, the mixture is condensed into liquid and gaseous product classes different
In separator, hydro sulfid and apart of light naphtha put out and apart return to the top of column
Apart of heavy naphtha was reduced, it put out. Apart go to reboiler and is mixed with hydro from separator. Naphtha at reboiler go back the column




3.1.3. Advantages
It is claimed that the technology of CDTech is about 25% less expensive than the conventional HDS process, making it very attractive for refineries
The percent yielded from reactants to products increased in some reactions from 96-97% to 99.9%
3.2. The counter- current operation
Aside from improving the catalysts, upgrading hydrotreating equipment is an option
Conventionally used hydrotreating reactors are fixed-beds with co-current supply of oil streams and hydrogen, resulting in unfavorable H2and H2S concentration profiles through the reactor
This technology use the ebullated bed reactor
3.2.1. Feedstock and catalyst
Feedstock: The mainly feedstock is the heavy feed such as deep cut heavy vacuum gas oil, coker gas oils and some residues
Catalyst:
- The catalyst used in bed 1,2 are metal sulfide catalysts such as sulfide Co-Mo/Alumina(excellent), Ni-Mo/Alumina( Very good), Ni-W/Alumina( Good). Catalyst in bed 3 is noble metal loaded on acidic support
-The catalyst particles are fluidized by the feed and hydrogen and are therefore well mixed with the feed stream. The catalyst activity can be controlled by adding and withdrawing catalyst particles
3.2.2. Proceses
The oil feed is put into the reactor at the top and hydrogen is put into at the bottom of the reactor, in the place where its presence is most desired
Hydro sulfid is removed from the reactor at the top, avoiding possible recombination of hydro sulfid and olefins at the reactor outlet
In the first stage, the feed and hydrogen co-currently contact the catalyst bed and the bulk of the organosulfur compounds is converted. This is followed by the removal of H2S from the reactant flow. The second stage of the reactor system operates in the counter-current mode providing more favorable concentration profiles of H2S and H2 over the length of the reactor
3.2.2. Advantages
a. Ebullated bed reactors offer high-quality, continuous mixing of liquid and catalyst particles
b. The advantages of a good back-mixed bed include excellent temperature control and, by reducing bed plugging and channeling, low and constant pressure drops
c. The Prime technology enables over 98% desulfurization of the entire FCC naphtha cut
d. Prime reactors fit easily into any refinery configuration and currently five units are in operation
4. Conclusion
This is the latest technologies in HDS
The yiel of advanced HDS is higher than conventional HDS
HDS process have good performance lead to the lower of sulfide in the environment
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