Wastewater desulfurization

ANALYSIS OF POWER PLANT FLUE CAS DESULFURIZATION WASTEWATERS (FGDW)... 

U.S. EPA Office of Water Engineering and Analysis Division, Inductively Coupled Plasma/ Mass Spectrometry for Trace Element Analysis in Flue Gas Desulfurization Wastewater, 2009, http //water.epa.gov/scitech/wastetech/guide/steam-electric/upload/Steam-Electric FGD Draft-SOP 2011. pdf. 

New chapter Emerging ICP-MS Application Areas - covers the three most rapidly growing areas analysis of flue gas desulfurization wastewaters, fully automated analysis of seawater samples using online chemistry procedures, and characterization of engineered nanoparticles... 

The general proportions may be varied from one end of the tower to the other to accommodate changing liquid volumes and physical properties. These towers have been used in diameters ranging from a few inches for laboratory work up to 2.4 m (8 ft) in diameter by 12.2 m (40 ft) tall for purposes of deasphalting petroleum. Other commercial services include furfural extraction of lubricating oils, desulfurization of gasoline, phenol recoveiy from wastewaters, and many others. Columns up to 4.5 m in diameter and up to 50 m in height have been constructed. 

Barometric condenser wastewater from the crystallizer, the final coolers, light oil recovery operations, ammonia still operation, coke oven gas condensates, desulfurization processes, and air pollution control operations... 

Chang and co-workers isolated strain Nocardia sp. CYKS2 from a dyeing industry wastewater using DBT as the sole sulfur source [27]. This strain also desulfurized DBT to the same product 2-HBP however, it had broader substrate specificity and was reported to desulfurize thiophenes, sulfides, and disulfides (Table 3) in addition to DBT. However, it did not desulfurize trithiane, thianthrene and 4,4 -thiodiphenol. The desulfurization experiments were conducted in batch with the rate reported as 0.279 mg-sulfur/L dispersion/h for DBT conversion. 

Apart from biocatalyst activity, several other parameters are important in development of a biodesulfurization process. These parameters include oil/water ratio, composition of aqueous phase used for biocatalyst suspension during desulfurization, biocatalyst loading, oil/water separation following completion of desulfurization, potential for biocatalyst recycle, recycle of aqueous phase to reduce fresh water usage and wastewater minimization, as well as secondary oil separation and purification operations. 

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

Coal liquefaction Fischer-Tropsch synthesis Synthesis of methanol Hydrogenation of oils Alkylation of methanol and benzene Polymerization of olefins Hydrogenation of coal oils, heavy oil fractions, and unsaturated fatty acids Adsorption of S02 in an aqueous slurry of magnesium oxide and calcium carbonate S02 or removal from tail gas Wet oxidation of waste sludge Catalytic desulfurization of petroleum fractions Wastewater treatment... 

Product disposal and/or utilization, the investment and the operating costs, the space requirement for the plant, the possible wastewater accumulation and the material conversion are all important criteria for the selection of a desulfurization plant. 

Desulfurization of hot iron by addition of calcium carbide leads to formation of a slag containing calcium sulfide and hydroxide as well as substantial amount of iron oxides. This slag is completely different than other metalurgical slags and may be effectively used for treatment of various acidic dr neutral wastewater containing heavy metal cations by hydroxide/sulfide precipitation, and, by removal of several components from wastewater by sorption and other interactions with iron oxides. 

Experiments have indicated that the desulfurization slag can be used for treatment of the blast furnace blowdown wastewater for removal of residual suspended solids and all objectionable soluble components except ammonia. The removal of soluble heavy metals from industrial effluents by application of tliis slag may be performed at a broader pH range than required for hydroxide or sulfide precipitation alone. 

In this work the feasibility of hot iron desulfurization slag application as a precipitation reagent for wastewater soluble heavy metals was studied. Experiments were performed on both slimulated wastewater containing 50 mg/L zinz in tap... 

Fig. 1. Release of hydroxide ions by the desulphurization slag to the simulated wastewater (mixing intensity 110sec = 80 rpm desulfurization slag dose from 2 to lOg/L)...

Fig. 4. Comparison of residual zinz concentration in the simulated wastewater after treatment by hydroxide and sulfide precipitation and by application of the desulfurization slag...

The hot metal desulfurization slag (dekish slag) constitutes a promissing material for treatment of some industrial wastewaters. 

The performed experiments indicated that the desulfurization slag was effective in treatment of a simulated wastewater containing 50 mg/L of zinc, over a broad pH range, and in the treatment of the blast furnace blowdown wastewater. In the latter case the treatment was effective in removal of all objectionable soluble components of the wastewater except ammonia. 

There are many methods for the desulfurization of nature gas, which can be classified into dry desulfurization, wet desulfurization, and catalytic adsorption. In the dry desulfurization, some solid sorbents, such as iron oxide, zinc oxide, activated carbon (AC), zeolites, and molecular sieves, are used. In wet desulfurization method, liquid-phase chemical/physical solvent absorption systems are usually used for scrubbing H2S amine-based processes are subject to equipment corrosion, foaming, amine-solution degradation, and evaporation, and require extensive wastewater treatment. As a result, this sulfur removal technology is complex and capital intensive,44 although the processes are still employed widely in the industry. The desulfurization of coal gasification gas will be reviewed in detail in Section 5.5. In the catalytic-adsorption method, the sulfur compounds are transformed into H2S by catalytic HDS or into elemental sulfur or SOx by selective catalytic oxidation (SCO), and then, the reformed H2S and SOx are removed by the subsequent adsorption. 

AC materials as porous materials with very high surface areas and large pore volume have been widely used in deodorization, decolorization, purification of drinking water, treatment of wastewater, and adsorption and separation of various organic and inorganic chemicals. Recently, some carbon materials have been reported for adsorptive desulfurization of liquid hydrocarbon fuels. 

Mixed cultures of sulfur bacteria are used industrially for the desulfurization of wastewater and waste gases by biological conversion to elemental sulfur which has colloidal properties [56, 57]. 

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