Sulfur Adsorption Capacity Research Articles

A New Adsorbent For Ambient Temperature Desulfurization of Natural Gas

The sulfur content of natural gas or any hydrocarbon fuel needs to be reduced to very low levels to ensure long-term stable electrochemical performance for both high and low temperature fuel cells. This paper presents the development and test results of a new physical adsorbent for natural gas desulfurization. The sorbent effectively removes all naturally occurring sulfur compounds and sulfur-bearing odorants at ambient temperature with very high capacity. In a series of tests, the sulfur adsorption capacity of the new material is compared to other commercially available and specially prepared sorbents. The new sorbent can also be fully regenerated. The effectiveness of the sorbent was tested in the presence of water vapor, which is present in natural gas at ppmv levels. The effect of operating temperature on capacity was evaluated. The efficacy of the sorbent for carbonyl sulfide removal was also investigated.

Desulfurization of Commercial Jet Fuels by Adsorption via π-Complexation with Vapor Phase Ion Exchanged Cu(I)−Y Zeolites

Desulfurization of a commercial jet fuel by vapor phase ion exchange (VPIE) Cu(I)−Y adsorbents were studied in a fixed-bed adsorber operated at ambient temperature and pressure. When used with an activated alumina guard bed, Cu(I)−Y(VPIE) provides by far the best adsorption capacities. In general, the adsorbents tested for total sulfur adsorption capacity at breakthrough follow the order Selexsorb CDX < Cu(I)−Y(VPIE) < Selexsorb CDX/Cu(I)−Y(VPIE). The best adsorbent, Selexsorb CDX/Cu(I)−Y(VPIE) (layered bed of 25 wt % activated alumina followed by Cu(I)−Y), is capable of producing 38 cm3 of jet fuel per gram of adsorbent with a weighted average content of 0.071 ppmw-S. The sorbent is also capable of producing about 50 cm3 of jet fuel with a sulfur content of less than 1 ppmw-S. These low-sulfur fuels are suitable for fuel cell applications. Regeneration tests have shown the sorbent capacity can be fully recovered using calcination/reduction methods. Gas chromatography−flame photometric detection results s...

New sorbents for desulfurization of diesel fuels via π‐complexation

AbstractDesulfurization of a commercial diesel fuel by different adsorbents was studied in a fixed‐bed adsorber operated at ambient temperature and pressure. In general, the adsorbents tested for total sulfur adsorption capacity at breakthrough followed the order: AC/Cu(I)‐Y &gt; Cu(I)‐Y &gt; Selexsorb® CDX (alumina) &gt; CuCl/γ‐Al2O3 &gt; activated carbon &gt; Cu(I)‐ZSM‐5. The best adsorbent, AC/Cu(I)‐Y (layered bed of 15 wt % activated carbon followed by Cu(I)Y), is capable of producing 30 cm3 of diesel fuel per gram of adsorbent with a weighted average content of 0.15 ppmw‐S, and about 20 cm3 of diesel fuel per gram of adsorbent with a weighted average content of 0.06 ppmw‐S. These low‐sulfur fuels are suitable for fuel cell applications. The added layer of carbon not only delayed the sulfur breakthrough significantly but also sharpened the sulfur wavefronts. GC‐FPD results showed that the π‐complexation sorbents selectively adsorbed highly substituted thiophenes, benzothiophenes, and dibenzothiophenes from diesel, which is not possible with conventional hydrodesulfurization (HDS) reactors. The high sulfur selectivity and high sulfur capacity of Cu(I)Y were because of π‐complexation. © 2004 American Institute of Chemical Engineers AIChE J, 50: 791–801, 2004

Desulfurization of Diesel Fuels via π-Complexation with Nickel(II)-Exchanged X- and Y-Zeolites

Desulfurization of a commercial diesel fuel (297.2 ppmw S) by different nickel(II)-exchanged faujasite zeolites was studied in a fixed-bed adsorber operated at ambient temperature and pressure. The zeolites were prepared by both liquid-phase (LP) and solid-state (SS) ion-exchange (IE) methods. In general, the adsorbents tested for total sulfur adsorption capacity at breakthrough followed the order: Selexsorb CDX (alumina)/Ni(II)-Y (SSIE-500) > Selexsorb CDX (alumina)/Ni(II)-X (LPIE-RT) > Ni(II)-Y (SSIE-500) > Ni(II)-X (LPIE-RT) > Ni(II)-Y (LPIE-135). The best adsorbent, Selexsorb CDX (alumina)/Ni(II)-Y (SSIE-500) [layered bed of 25 wt % activated alumina followed by Ni(II)-Y] is capable of producing 19 cm3 of diesel fuel per gram of adsorbent with a weighted average content of 0.22 ppmw S. These low-sulfur fuels are suitable for fuel cell applications. The sorbents were fully regenerated in one step using air at 350 °C, which simplifies possible implementation for many applications. GC−FPD results showed that the π-complexation sorbents selectively removed highly substituted thiophenes, benzothiophenes, and dibenzothiophenes from diesel, which is not possible using conventional hydrodesulfurization (HDS) reactors or direct sulfur−metal interaction-based zeolites such as Ce(IV)-Y. The high sulfur selectivity and high sulfur capacity of nickel(II)-zeolites were due to π-complexation.

Selective Adsorption for Removing Sulfur from Jet Fuel over Zeolite-Based Adsorbents

Adsorbents based on transition metal ion-exchanged Y zeolites (with Cu, Ni, Zn, Pd, and Ce ions) were synthesized and evaluated for the adsorptive desulfurization of a model jet fuel (MJF) and a real jet fuel (JP-8). Among the adsorbents tested, Ce-exchanged Y zeolites exhibited better adsorption capacity of about 10 mg of sulfur/g of adsorbent at 80 °C with a MJF containing 510 ppmw sulfur. The same adsorbent exhibited a sulfur adsorption capacity of about 4.5 mg/g for the real JP-8 jet fuel containing about 750 ppmw sulfur. Desulfurization of MJF under flow conditions at 80 °C showed a breakthrough capacity of about 2.3 mg/g of adsorbent. Ce-exchanged zeolites exhibited higher selectivity for sulfur compounds as compared to the selectivity of aromatics, for which a comparative study indicated that the sulfur compounds are adsorbed over Ce-exchanged Y zeolites via direct sulfur−adsorbent (S−M) interaction rather than via π-complexation. While the selectivity for 2-methyl benzothiophene (2-MBT) was higher in the static adsorption studies, the adsorption selectivity decreased in the order 5-methyl benzothiophene (5-MBT) > benzothiophene (BT) > 2-MBT under dynamic conditions. This trend was correlated to the electron density on sulfur atoms derived from computer-aided molecular orbital calculations.

Investigation of relation between both sulfur removal and adsorption capacity with surface morphology of a pyrolysed Turkish lignite ☆

In considering with morphological physicochemical transformations of the coal samples pyrolysed in CO 2 atmosphere at different temperatures, the change of their adsorptive capacities have been investigated. It was seen that the change occurred in the monolayer adsorption capacities as parallel to morphological transformations of the coal surface is particularly connected with the amount of organic sulfur present in the coal matrix. Adsorption capacity is not affected from the contents of pyritic sulfur and ash of coal samples. The measurements of zeta potential of the pyrolysed coal samples also showed that pyrolysis modified the functional groups on surface of the coal, depending on the pyrolysis temperature.

XPS studies of the effect of Mn on [formula omitted

The effect of Mn on Pd Al 2O 3 is studied by XPS. Mn decreases the electronic density of Pd and thus its sulfur adsorption capacity, producing a decrease in activity and selectivity during the selective hydrogenation of styrene to ethylbenzene.

High alcohol synthesis from CO and H2 on ruthenium catalysts

AbstractA Ru/MoO2 catalyst was found to be active for the synthesis gas conversion to straight chain primary alcohols. Potassium carbonate was effective for enhancing high alcohol formation. The carbon number distribution of the alcoholic products followed the Anderson‐Schulz‐Flory distribution which gave chain growth probabilities of 0.27–0.35. In addition, the Ru/MoO2 catalysts are significantly more sulfur resistant than a Ru/Al2O3 catalyst. The higher sulfur resistance of these catalysts is mainly due to their higher sulfur adsorption capacities.