Desulfurization efficiency

Ross (R2) reported measurements of desulfurization efficiency of fixed-bed pilot and commercial units operated under trickle-flow conditions. The percentage of retained sulfur is given as a function of reciprocal space velocity, and the curve for a 2-in. diameter pilot reactor was found to lie below the curves for commercial units it is argued that this is proof of bad liquid distribution in the commercial units. The efficiency of the commercial units increased with increasing nominal liquid velocity. This may be an effect either of mass-transfer resistance or liquid distribution. 

Flow rate ratio of atomizing air to flue gas Specific productivity of the reactor Hydraulic resistance of the reactor Desulfurization efficiency, %... 

It is widely recognized today that coal desulfurization efficiency depends on the distribution of sulfur in the original coal to pyritic and organic sulfur. Pyritic sulfur can be desulfurized, but it is more difficult to remove organic sulfur. 

Huang et al. investigated a different desulfurization method using ionic hquids [63]. Here, an ionic hquid was fabricated with a Cu( 1) group, which was used at the University of Michigan for soHd-Hquid adsorption. This ionic hquid, BMIMCU2CI3, binds the sulfur compounds via a tr-complex and has better desulfurization efficiency than the hquids investigated by Esser [62]. 

The SURE model can also easily explain (24) the observed dependency of the oxygen concentration in the combustor outlet as a function of the excess air ratio X (Fig. 11) and the generally observed decrease of the desulfurization efficiency during substoichiometric (staged) combustion (Fig. 12). Quantitative validation of these last phenomena is, however, hampered by the lack of reliable data... 

The plant has obtained a 90% desulfurization efficiency, using 2.3% sulfuric acid concentration and a liquid-to-gas ratio of 210 gal/1,000 scf (97,000 gpm). 

Therefore, the lower the oxygen, the better the desulfurization. Numerous studies (6-9) have shown the benefits that doloma-based refractories offer regarding desulfurization efficiency. Additionally, for desulfurization and inclusion removal, a fluid, highly basic slag is required. The optimum slag composition for these purposes is shown in Table 4. Doloma refractories are very compatible with the same slag practice that optimizes the refining processes used to produce clean and low-sulfur steel. 

Using potassium superoxide as oxidant very similar desulfurization efficiencies in both model compounds and real diesel samples was achieved, with a significantly lower sulfur/ oxidant ratio. In... 

Single-bond cleavage with molecular hydrogen is termed hydrogenolysis. Palladium is the best catalyst for this purpose, platinum is not useful. Desulfurizations are most efficiently per-formed with Raney nickel (with or without hydrogen G.R. Pettit, 1962 A or with alkali metals in liquid ammonia or amines. The scheme below summarizes some classes of compounds most susceptible to hydrogenolysis. 

Ladle metallurgy, the treatment of Hquid steel in the ladle, is a field in which several new processes, or new combinations of old processes, continue to be developed (19,20). The objectives often include one or more of the following on a given heat more efficient methods for alloy additions and control of final chemistry improved temperature and composition homogenisation inclusion flotation desulfurization and dephosphorization sulfide and oxide shape control and vacuum degassing, especially for hydrogen and carbon monoxide to make interstitial-free (IF) steels. Electric arcs are normally used to raise the temperature of the Hquid metal (ladle arc furnace). 

Other Uses. Other uses include intermediate chemical products. Overall, these uses account for 15—20% of sulfur consumption, largely in the form of sulfuric acid but also some elemental sulfur that is used directly, as in mbber vulcanization. Sulfur is also converted to sulfur trioxide and thiosulfate for use in improving the efficiency of electrostatic precipitators and limestone/lime wet flue-gas desulfurization systems at power stations (68). These miscellaneous uses, especially those involving sulfuric acid, are intimately associated with practically all elements of the industrial and chemical complexes worldwide. 

Although desulfurization is a process, which has been in use in the oil industry for many years, renewed research has recently been started, aimed at improving the efficiency of the process. Envii onmental pressure and legislation to further reduce Sulfur levels in the various fuels has forced process development to place an increased emphasis on hydrodesulfurization (HDS). For a clear comprehension of the process kinetics involved in HDS, a detailed analyses of all the organosulfur compounds clarifying the desulfurization chemistry is a prerequisite. The reactivities of the Sulfur-containing structures present in middle distillates decrease sharply in the sequence thiols sulfides thiophenes benzothiophenes dibenzothio-phenes (32). However, in addition, within the various families the reactivities of the Substituted species are different. 

The synthesis of monocyclic thiepins from thiophene and dimethyl acetylenedicarboxylate is often accompanied by the loss of sulfur. In particular, in cases where room temperature is required for efficient rates of cycloaddition and rearrangement76 (see Section 2.1.3.3.), the desulfurization reaction proceeds rather quickly with the consequence that thiepin formation can be monitored by low temperature HNMR spectroscopy, but the products cannot be isolated.76 - 78 However, in the case of thiepin 1 where R1 = R2 = C02Me and R3 = H, refluxing toluene is necessary for the extrusion of sulfur.78... 

D. P. Harrison, F.R. Groves, W. N. Huang, A. L. Ortiz, J.D. White, Y. Zeng, et al., High Efficiency Desulfurization on Synthesis Gas, Final Report, Louisiana State University, 1998. 

Since the chemistry of the C-Se bond is very similar to the chemistry of the C-S bond, the deselenation procedures are also very similar to the desulfurization methods. Thus, Ra-Ni is an efficient reagent in hydrogenolytic desel-enations, but the outcome of the reaction depends on the preparation of the catalyst.426 28... 

A similar approach via desulfurization of the thiosemicarbazide-substituted pyrimidone 290 using 4-nitrobenzyl bromide leads to efficient formation of the tricyclic system 291 in excellent yield (Equation 79) <2000RJ0430>. 

Removal of the residual water from the desulfurized oil phase (e.g., using high-efficiency separators such as electrostatic separators). 

Kishimoto, M. Inui, M. Omasa, T., et al., Efficient production of desulfurizing cells with the aid of expert system. Biochemical Engineering Journal, 2000. 5(2) pp. 143-147. 

An improving in the culturing technique was conceived as feeding the sulfur solely source compound as a rate equal to that of the microorganism intake so as needed for growth [126], This optimization technique is believed to act in two ways, for the proliferation efficiency of the microorganism in the culturing medium and for the desulfurization activity and substrate specificity. 

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