Reduction, sulfur

Conventional coal cleaning processes can remove about 50% of pyritic sulfur and 30% of total sulfur. For northern Appalachian region coals it has been shown that a greater sulfur reduction can be achieved by applying physical coal cleaning to finer size coals (Table 3) (8). 

Table 3. Effects of Physical Cleaning on Sulfur Reduction in Coal ...

Tailpipe emissions of HC and CO are affected by the levels of heavy aromatics in gasoline. Like sulfur, the heavy aromatics are in the back end of the boiling range (Figure 10-4). As with sulfur, reduction of end point directly controls the concentration of heavy aromatics in finished gasoline. 

Further developments in the effectiveness of the FCC gasoline sulfur reduction additives will allow a number of refiners to meet the required reduction in gasoline sulfur without undertaking costly capital projects. Additionally, improvements in the CO promoter additives will reduce NO emissions when the promoter is used. Finally, other... 

Ma K, R Weiss, MWW Adams (2000) Characterization of hydrogenase II from the hyperthermophilic archaeon Pyrococcus furiosus and assessment of its role in sulfur reduction. J Bacteriol 182 1864-1871. 

Searcy DG, Lee SH. 1998. Sulfur reduction by human erythrocytes. J Exp Zool 282 310-322. 

The treatment of hydrotreated diesel oil (250 ppm sulfur) to achieve deep desulfurization by CYKS1 was also reported [192], Sulfur reduction to 61 ppm was reported within 20 hours using 18.6 g/L biocatalyst concentration and water/oil ratio of 10. A rate of 10.6 mmol/kg dcw/h was reported for first four hours however, the rate was significantly reduced thereafter. 

Use of a N. globerula R-9 strain was demonstrated for desulfurization of straight run diesel oils. Sulfur reduction from 1807 to 741 mg/dm3 was reported at a desulfurization rate of 5.1 mmol/Kgdcw/h. The desulfurization of model oils containing DBT and 4,6 dimethyl DBT was studied and Michaelis-Menten kinetic parameters were reported. 

Gasoline sulfur reduction, 11 686-689 catalyst/additive technologies for,... 

In the rings containing sulfur, reduction of sulfoxides of phenoxathiin and thianthrene can be performed in excellent yield with the aluminium chloride/sodium iodide or zinc dust/l,4-dibromobutane systems <1996CHEC-II(6)447>. 

In the United States and other parts of the world, both low-sulfur diesel fuel and high-sulfur diesel fuel are being refined. Because fuel sulfur level has been identified as the primary component of fuel emission particulates and acid rain, sulfur reduction has been mandated and implemented. 

Hydrogen sulfide formation through dissimilatoiy sulfur reduction has for years been known as a source of environmental sulfur. This compound has invited recent study because of its possible effect on the redox chemistry of sea water. Both the lifetime and the oceanic concentrations of this reactive and highly toxic compound are the focus of the fifth section. 

An example of sulfur reduction is disulfide reduction, as shown by the following reaction ... 

There have been several assessments of the potential of physical coal cleaning for reducing SO2 emissions (29-31). Maronde and Deurbrouck ( 1) estimated the maximum potential sulfur reduction that could be achieved through extensive cleaning of coals from the Northern Appalachian Region Maryland, Ohio,... 

Table V presents sulfur reduction data for two of the major coal seams in the region the Pittsburgh Seam and the Lower Kittanning Seam. Laboratory washability (float-and-sink) analyses of representative samples of these coals were used to determine potential sulfur reductions at various levels of cleaning. To assess the impact on regional SO2 emissions, sulfur reduction potentials were estimated for only those coals both produced and utilized in the Northern Appalachian Region. The "Present Level" of cleaning shown in the table represents estimated base-line values for the amount of sulfur in the coal product. These values take into consideration any coal cleaning that occurred, and are compared to coal sulfur contents that would result from more intense levels of cleaning. Each of the 11 major coal-producing seams in the region were evaluated in this manner.

Table V. Theoretical Effects of Coal Cleaning on Sulfur Reduction for Two Northern Appalachian Coals Mined in 1982...

Level of Cleaning Clean Coal Product - Thousands Sulfur of Tons - Sulfur Reduction (Percent) Mining Requirement, Thousands of Tons... 

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