Fine desulfurizer

Another possibility of keeping the expenditure on fine desulfurization units witlm reasonable limits is the addition of 1,2-dimethylimidazole [2.8] to the NMP. This additive has the effect that almost all the COS entering the H2S elimination stage is hydrolized to H2S and CO2. Instead of the 200ppm mentioned in the first example, only 5-10 ppm of COS would in this case leave the H2S wash unit while the balance would be removed in the form of H2S. 

The Purisol process can be used also for what has been termed the all-out puriflcation process required to produce methanol from gases resulting from medium temperature gasification of coal, which contain relatively little CO but more CO2 than required. However, if NMP is to be used for such applications, it will be necessary not only to increase the sulfur content of the sulfur offgas, but also to provide for additional fine desulfurization. 

Fine desulfurizer at room temperature. Since the end of 1980s, Imperial Chemical Industries Ltd (ICI) developed a fine desulphurization process on Hydrolyzed Zinc Oxide at room temperature. Yuhua Kong et al in Hubei Institute of Chemistry, China, developed T504 catalysts for COS hydrolysis and TlOl activated carbon fine desulfurizer successfully, and achieved fine desulphurization at room temperature, with the sulfur content below O.lmg/m in the gas after desulphurization. These desulfurizers are suitable to protect the catalysts for the methanation, ammonia synthesis and methanol synthesis. 

Zinc—bromine storage batteries (qv) are under development as load-leveling devices in electric utilities (64). Photovoltaic batteries have been made of selenium or boron doped with bromine. Graphite fibers and certain polymers can be made electrically conductive by being doped with bromine. Bromine is used in quartz—haUde light bulbs. Bromine is used to etch aluminum, copper, and semi-conductors. Bromine and its salts are known to recover gold and other precious metals from their ores. Bromine can be used to desulfurize fine coal (see Coal conversion processes). Table 5 shows estimates of the primary uses of bromine. 

Oxidative Desulfurization Process. Oxidative desulfurization of finely ground coal, originally developed by The Chemical Constmction Co. (27,28), is achieved by converting the sulfur to a water-soluble form with air oxidation at 150—220°C under 1.5—10.3 MPa (220—1500 psi) pressure. More than 95% of the pyritic sulfur and up to 40% of the organic sulfur can be removed by this process. 

Some cokeless technologies in use or under development include the Japanese direct iron ore smelting (DIOS) process, in which molten iron is produced directly with coal and sinter feed ore, the HIsmelt process, where ore fines and coal are used to achieve a production rate of 8 t/h using ore directly in the smelter, and the Corex process, which has an integral coal desulfurizing step, making it amenable to a variety of coal types.14... 

Sulfur emissions from combustion processes can be reduced by switching to a fuel with lower sulfur. The sulfur content of fuels varies significantly. Generally, the sulfur content is gas < liquid < solid. This order arises mainly from the relative ease with which the fuels can be desulfurized. Desulfurizing coal prior to combustion is extremely difficult. It must be first ground to very fine particles (of the order of 100 xm) to liberate the mineral (inorganic) sulfur. The light coal can then be... 

ExxonMobil extended the Hydrofining technology to produce a 200 ppm diesel, with the Diesel Oil Deep Desulfurization technology, DODD. The reactor is packed with multiple beds of different catalysts. A preceding history of commercial experience provided data to build a model for deep HDS and pave the way to a new technology, MAK Fining. 

Davison, J., The lambda process - for desulfurization of slurry coal fines prior to combustion, in Eighth Annual Surface Mine Drainage Task Force Symposium. 1987. Morgantown, West Virginia, April 7-8. 

Cutting oils and aqueous metal working fluids Industrial wastewater Agricultural waste and runoff Cyanide contamination Desulfurization of coal fines Chlorinated aliphatics Pesticides... 

Elemental Composition of Atmospheric Fine Particles Emitted from Coal Burned in a Modern Electric Power Plant Equipped with a Flue-Gas Desulfurization System... 

Improved control devices now frequently installed on conventional coal-utility boilers drastically affect the quantity, chemical composition, and physical characteristics of fine-particles emitted to the atmosphere from these sources. We recently sampled fly-ash aerosols upstream and downstream from a modern lime-slurry, spray-tower system installed on a 430-Mw(e) coal utility boiler. Particulate samples were collected in situ on membrane filters and in University of Washington MKIII and MKV cascade impactors. The MKV impactor, operated at reduced pressure and with a cyclone preseparator, provided 13 discrete particle-size fractions with median diameters ranging from 0,07 to 20 pm with up to 6 of the fractions in the highly respirable submicron particle range. The concentrations of up to 35 elements and estimates of the size distributions of particles in each of the fly-ash fractions were determined by instrumental neutron activation analysis and by electron microscopy, respectively. Mechanisms of fine-particle formation and chemical enrichment in the flue-gas desulfurization system are discussed. 

Although the Claus catalytic conversion is a highly efficient process as presently employed in sulfur recovery plants the continuing efforts to reduce sulfur emissions to atmosphere demand that the last possible ounce of efficiency be squeezed from the process. Whether further small but critical improvements in the already high sulfur recovery efficiency can be achieved by more fine tuning of the converters and their catalyst charge remains to be seen. What cannot be accomplished in the catalytic converters will be achieved in the tail gas desulfurization processes. 

Sulfate - pRUG DELIVERY SYSTEMS] (Vol 8) - [FIBERS-ACRYLIC] (Vol 10) - [CELLULOSE] (Vol 5) - [COALCONVERSION PROCESSES - CLEANING AND DESULFURIZATION] (Vol 6) - [COALCONVERSION PROCESSES - CLEANING AND DESULFURIZATION] (Vol 6) - [COALCONVERSION PROCESSES - CLEANING AND DESULFURIZATION] (Vol 6) - [COAL] (Vol 6) - [FILTRATION] (Vol 10) - [FINE ARTEXAMINATION AND CONSERVATION] (Vol 10) -in geothermal resources [GEOTHERMAL ENERGY] (Vol 12) -m phosphoric acids [PHOSPHORIC ACID AND PHOSPHATES] (Vol 18) -in steam [STEAM] (Vol 22)... 

A naphtha is desulfurized by reducing its thiophene content with hydrogen at 660 K and 30 atm.The reaction is apparently first order with k = 0.3 cc thiophene/(g catalyst)(sec). The catalyst particle diameter is 0.35 cm, true density 2.65 g/cc, specific surface 180 m2/g, porosity 40%, In an experiment with very fine particles, conversion was 90%, but with the particles in question it was 70%. Find the effectiveness of the catalyst and the tortuosity of the pores. 

The LC-Fining process is a hydrogenation process capable of desulfurizing, demetallizing, and upgrading a wide spectrum of heavy feedstocks (Tables 9-12 and 9-13) by means of an expanded bed reactor (Fomoff, 1982 Reich et al., 1993 Hydrocarbon Processing, 1998). 

The LC-Fining process has been applied to desulfurization of bitumen extracted from the Athabasca tar sands (Bishop, 1990). In one reported instance, a low-solids bitumen and a high-solids bitumen were employed as feedstocks whereupon good conversion of the bitumen to lower-sulfur products was noted... 

In the process (Figure 9-37), the residue feed is slurried with a small amount of finely powdered additive and mixed with hydrogen and recycle gas prior to preheating. The feed mixture is routed to the liquid phase reactors. The reactors are operated in an up-flow mode and arranged in series. In a once through operation conversion rates of >95% are achieved. Typically the reaction takes place at temperatures between 440 and 480°C and pressures between 150 and 250 bar. Substantial conversion of asphaltenes, desulfurization and denitrogenation takes place at high levels of residue conversion. Temperature is controlled by a recycle gas quench system. 

LC-Fining process a hydrogenation process capable of desulfurizing, demetallizing and upgrading heavy feedstocks by means of an expanded bed reactor. 

Ondov, J.M., Biermann, A.H., Heft, R.E., Koszykowski, R.F., Elemental Composition of Atmospheric Fine Particles Emitted from Coal Burned in a Modern Electric Power Plant Equipped with a Flue-Gas Desulfurization System. American Chemical Society Symposium Series no. 167, 173-186 (1981). 

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