CATALOG
1. Introduction 4
2. The solution for turning the amount of sulfur down-HDS 7
2.1. To apply this method, we have to understand clearly about HDS. The question is What is HDS? 7
2.2. Environmental legislation on diesel fuel specification 8
2.3. Market demand for ULSD fuel 8
3. Inhibition effects 10
3.1. Effect of 𝑯𝟐𝑺 10
3.2. Efect of 𝑯𝟐𝑺 12
3.3 . Effect of aromatics content 13
4. Catalyst development for deep 15
4.1. Catalyst components 15
4.2. Nature of active phrase 15
4.3. Preparation of ultra deep HDS catalysts 17
4.3.1. Support effects 18
4.3.2. Effect of additives 19
4.3.3. Improvements in catalyst impregnation techniques 20
4.4. Unsupported catalysts 20
4.5. Improved commercial deep HDS catalysts 22
5. Feed quality effect 23
5.1 Properties of diesel feeds 23
5.2. Feed quality effect on HDS reactivity 24
6. Effect of process variables and thermodynamic limitation 28
7. Revamping of hydrotreaters for ULSD production 29
8. Deep HDS process technology developments 29
8.1. Two-stage processes sections. 30
8.2. IsoTherming technology 32
9. Oxidative desulfurization 32
9.1. Desulfurization by adsorption 33
9.2. Desulfurization by physical adsorption 33
9.3. Mechanism of reactive adsorption desulfurization 34
9. 4. Extractive desulfurization 35
9.5. Biodesulfurization 35


1. Introduction
The environment is a big deal problem in all over the world at the moment. The combustion of fossil fuels containing Oil and gas is one of the most factor impacting to our house - the environment by releasing SOx, NOx causing acid rain. The big problem need the chemical engineering have to solve, which is cut back on the amount of S, N releasing to the environment.

//

Dealing with big problem , what is the solution?
As you know that sulfur in the oi and gas is cause of lots of problems.
First of all, sulfur in the refining Oil and Gas will corrode facilities of refining petroleum. Moreover sulfur is a main cause of reducing active sites and poison the catalyst which leading to reduce the life of catalyst.
In addition, sulfur is root of environmental problems and health hazards.
Diesel fuels contain a complex mixture of hydrocarbons having different molecular weights and boiling points composed of mainly paraffins and aromatics together with small amounts of organic sulfur and nitrogen compounds. The sulfur present in the diesel fuel is a major source of air pollution. During combustion in the diesel engines, the sulfur compounds burn to form harmful sulfur oxides (SOx) and sulfate particulates. The nitrogen compounds are oxidized to nitrogen oxides (NOx). The exhaust emissions contain SOx, NOx, CO, CO2, PM and unburned hydrocarbons (HC). Several studies have shown that the amount of SOx emissions is directly proportional to the amount of sulfur contained in the fuel. In addition, total particulate mat-ter (PM) emissions are proportional to the amount of sulfur in the diesel fuel [5,7,48–50]. In the oxygen rich exhaust of diesel vehi-cles, the organic “S” is converted into SOx, consisting mainly SO3which dissolves in the water vapor present to form sulfuric acid (H2SO4) vapor. H2SO4 forms very small (so called ultrafine) parti-cles in diesel exhaust which are considered especially hazardous because of their ability to penetrate deeply into the lungs. The influence of sulfur content of diesel fuel on direct PM emissions is illustrated in the figured 1.

/
According to the US EPA, approximately 2% of the sulfur in the diesel fuel is converted to direct PM emissions. The oxides of S and N(i.e. SOx and NOx) and the PM present in the diesel engine exhaust emission and deteriorate the air quality and cause adverse effects on human health [6]. The particular matter (PM) emitted from diesel engine consists of three primary constituents: a carbonaceous core, a soluble organic fraction (SOF) and a mixture of SOx and water, and has been found to be a human carcinogen.
Emission control devices such as Diesel Oxidation Catalysts (DOC), NOx absorbers, PM filters and selective catalyst reduction (SCR) systems are commonly used in diesel vehicles to control and minimize the hazardous effects of diesel engine exhaust emissions. Oxidation catalysts work by oxidizing CO, HC and the soluble organic fraction of the PM to CO2 and H2O in the oxygen rich exhaust stream of the diesel engine. When sulfur is present in the fuel, DOCs also increase the oxidation rate of SO2, and produce high level of hazardous sulfate in the emission (Fig. 2) .

/