Hydrodesulfurization reactivities of various sulfur compounds in diesel fuel

Ma, Xiaoliang; Sakanishi, Kinya; Mochida, Isao

doi:10.1021/ie00026a007

Cited by 433 publications

(245 citation statements)

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“…The majority of sulfur-containing hydrocarbons in liquid fuels are converted to sulfur-free compounds and H 2 S by catalytic hydrodesulphurization (HDS) reactions during the fuel processing. Although the HDS process is the best known technology for desulfurization of liquid fuels, it cannot efficiently remove thiophenic compounds (TC) including dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and benzothiophene (BT) to meet the new environmental regulations of 15-30 ppm sulfur in the processed fuels [1][2][3][4][5]. Reactivity studies of BT, DBT and their alkylated homologues in HDS reactions over Co, Mo/Al 2 O 3 , Ni, Mo/Al 2 O 3 and sulfide Co, Mo/γ-Al 2 O 3 catalysts indicate that the alkyl group substituents, especially in positions subject to steric hindrance effects (e.g., 4 and 6 in the 4,6-DMDBT molecule) significantly reduce the reactivity of TC in HDS reactions [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Thiophenic Compounds from Model Diesel Fuel Using Copper and Nickel Impregnated Activated Carbons

2012

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Adsorption of sulfur compoundsby porous materials is an effective way to produce cleaner diesel fuel.In this study, adsorption of refractory thiophenic sulfur compounds, i.e., benzothiophene (BT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) in single-solute systems from n-hexane solutions onto metal-impregnated activated carbons was investigated. A hydrogen-treated activated carbon fiber was selectively loaded with Ni, NiO, Cu, Cu 2 O, and CuO species to systematically assess the impact of each metal species on the adsorption of thiophenic compounds (TC). Metal-loaded adsorbents had the same total metal contents and similar microporosities, but contained different types of copper or nickel species. All metal-loaded adsorbents showed enhanced adsorption of tested TC. Cu 2 O-or NiO-loaded adsorbents exhibited the highest uptakes, due to more specific interactions between Cu + or Ni 2+ species and TC molecules. The theoretical monolyer coverage of TC on the exposed Cu + sites was estimated and compared with that calculated from the experimental data. Results suggested catalytic conversion of TC molecules to other compounds on the Cu + sites, followed by adsorption of reaction products onto the carbon surface or multilayer accumulation of TC molecules on the Cu + sites. TC adsorption uptake of the majority of adsorbents followed the order of: 4,6-DMDBT > DBT > BT due to higher intensity of specific and non-specific interactions of larger TC molecules with adsorbents.

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Section: Introductionmentioning

confidence: 99%

Adsorption of Thiophenic Compounds from Model Diesel Fuel Using Copper and Nickel Impregnated Activated Carbons

2012

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“…Identification of the sulfur components in the fuels is based on a combination of various techniques, including HPLC, sulfur-selective ligand exchange chromatography (Ma et al, 1997), GC-MS (Ma et al, 1994(Ma et al, , 1997, retention time comparison with literature data (Depauw and Froment, 1997;Chawla and Sanzo, 1992) HDS reactivities of various sulfur compounds (Ma et al, 1994;] and understanding of the elution order of the isomers (Lai and Song, 1995).…”

Section: Sample Analysismentioning

confidence: 99%

Deep Desulfurization of Diesel Fuels by a Novel Integrated Approach

Ma¹,

Sprague²,

Sun³

et al. 2002

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In order to reduce the sulfur level in liquid hydrocarbon fuels for environmental protection and fuel cell applications, deep desulfurization of a model diesel fuel and a real diesel fuel was conducted by our SARS (selective adsorption for removing sulfur) process using the adsorbent A-2. Effect of temperature on the desulfurization process was examined. Adsorption desulfurization at ambient temperature, 24 h -1 of LHSV over A-2 is efficient to remove dibenzothiophene (DBT) in the model diesel fuel, but difficult to remove 4-methyldibenzothiophene (4-MDBT) and 4,6-dimethyl-dibenzothiophene (4,6-DMDBT). Adsorption desulfurization at 150 ˚C over A-2 can efficiently remove DBT, 4-MDBT and 4,6-DMDBT in the model diesel fuel. The sulfur content in the model diesel fuel can be reduced to less than 1 ppmw at 150 ˚C without using hydrogen gas. The adsorption capacity corresponding to the break-through point is 6.9 milligram of sulfur per gram of A-2 (mg-S/g-A-2), and the saturate capacity is 13.7 mg-S/g-A-2. Adsorption desulfurization of a commercial diesel fuel with a total sulfur level of 47 ppmw was also performed at ambient temperature and 24 h -1 of LHSV over the adsorbent A-2. The results show that only part of the sulfur compounds existing in the low sulfur diesel can be removed by adsorption over A-2 at such operating conditions, because 1) the all sulfur compounds in the low sulfur diesel are the refractory sulfur compounds that have one or two alkyl groups at the 4-and/or 6-poistions of DBT, which inhibit the approach of the sulfur atom to the adsorption site; 2) some compounds coexisting in the commercial low sulfur diesel probably inhibit the interaction between the sulfur compounds and the adsorbent. Further work in determining the optimum operating conditions and screening better adsorbent is desired.3 2. IntroductionThe overall objective of this project is to explore a new desulfurization system concept, which consists of efficient separation of the refractory sulfur compounds and effective hydrodesulfurization of the concentrated fraction of the refractory sulfur compounds in diesel fuels.The major challenge to our proposed approach is to attract and selectively adsorb sulfur compounds onto the surface of the solid adsorbent but leave the aromatic and For the automotive fuel cells and micro-fuel cells, liquid hydrocarbons are promising candidate fuels due to their higher energy density and safety for transportation and storage. For the automotive fuel cells, especially for the current developing SOFC and PEFC auxiliary power unit for automobile, gasoline and diesel are preferred fuels as their ready availability and the existing infrastructure in production, delivery and storage.However, the current commercial gasoline and diesel usually contain significant amounts of sulfur up to 350 and 500 ppmw, respectively. The sulfur compounds in the fuels and H 2 S produced from these sulfur compounds in the hydrocarbon reforming process are poisonous to both the catalysts in hydrocarbon fuel processo...

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“…It was observed that the overall kinetics for the HDS of these species could be described by lumping the rate constants for the individual sulfur species into four reactivity groups [60][61][62][63][64]. These groups, listed in order of decreasing reactivity, are as follows:…”

Section: Reactivity Of Poly Aromatic Sulfur Compoundsmentioning

confidence: 99%