Fate Of Sulfur Research Articles

Inorganic Aerosols and Their Role in Catalyzing Sulfuric Acid Production in Furnaces

ABSTRACT Submicrometer ash and sulfur oxides are important pollutants formed during pulverized coal combustion. The submicrometer ash contains known catalysts for sulfur dioxide oxidation as well as alkaline species that will react with sulfur oxides. This work was an investigation to determine if submicrometer ash-sulfur oxide interactions can have a significant impact on the fate of sulfur. The submicrometer-ash-sulfur oxide interaction studies were carried out using submicrometer ash of controlled composition generated from the combustion of synthetic chars. The submicrometer ash was either exposed to SO2 in the combustion chamber or immobilized on a quartz-fiber filter for later exposure to SO2. Submicrometer-ash catalysis of SO2 oxidation was found to contribute significantly to the SO3 formed in the convective passes of a utility boiler, depending on the coal, combustion conditions, and temperature profile in the convective section. The calcium within the freshly formed submicrometer ash appears to sulfate more rapidly than would be predicted from rates published in the literature and is expected to sulfate completely in the con-vective section of a utility boiler.

97/04879 Investigation into the effect of dolomite upon the fate of sulfur, nitrogen, chlorine, and trace elements during the flash pyrolysis of Polish coals: Bartle, K. D. et al. DGMK Tagungsber., 1997, 9703, (Proceedings ICCS '97, Volume 2), 609–612

97/04879 Investigation into the effect of dolomite upon the fate of sulfur, nitrogen, chlorine, and trace elements during the flash pyrolysis of Polish coals: Bartle, K. D. et al. DGMK Tagungsber., 1997, 9703, (Proceedings ICCS '97, Volume 2), 609–612

96/06360 The fate of sulfur, chlorine and trace elements during the flash pyrolysis of coal

96/06360 The fate of sulfur, chlorine and trace elements during the flash pyrolysis of coal

96/03499 Origin and fate of sulfur in Spanish coals

96/03499 Origin and fate of sulfur in Spanish coals

Artificial maturation of Monterey kerogen (Type II-S) in a closed system and comparison with Type II kerogen: Implications on the fate of sulfur

Artificial maturation of Monterey kerogen (Type II-S) in a closed system and comparison with Type II kerogen: Implications on the fate of sulfur

Artificial maturation of Monterey kerogen (Type II-S) in a closed system and comparison with Type II kerogen: implications on the fate of sulfur

Closed system pyrolysis was performed on a Monterey sulfur-rich kerogen (Type II-S) in the temperature range 300–500°C using varying pyrolysis times. Compared to a typical Type II marine kerogen (Toarcian) the Monterey kerogen decomposes at a faster rate. Significant differences in maturation characteristics of Monterey kerogen are: (1) earlier generation of the C 14+ fraction, (2) greater amounts of H 2S, and (3) dominant organic sulfur moieties in the pyrolysis extracts (alkylthiophenes). The results show that the rate of generation of alkylthiophenes is higher than the rate of generation of n-alkanes for this sulfur-rich kerogen. The alkylthiophenes may be produced during the pyrolysis of sulfur-rich organic matter.

Fate of sulfur(IV) dechlorinating agents in natural waters: effect of suspended sediments

To investigate the fate of SO/sub 2/ in dechlorinated waste water effluents, oxidation rates were measured in nonilluminated solutions at near-neutral pH and 25/degrees/C. River water was simulated with 0.01 M NaCl, 0.001 M buffer, and 1 g/L standard sediment MESS-1. Components leached from the sediment catalyzed the oxidation of S(IV) by O/sub 2/, but the particles themselves exerted a slight inhibitory effect. Sulfate was the major reaction product. Some nonoxidative loss of S(IV) to particles was observed at high-sediment concentrations (20 g/L). Sulfur(IV) reductively dissolved 25% of the Cu from the sediment, possibly an environmentally harmful process. Iron and manganese dissolutions were insignificant. The rate of loss of S(IV) from air-saturated solutions covering a 50-fold S(IV) concentration range as well as described by the empirical equation (time in s and concentrations in M) -d(SO/sub 3//sup 2 -/)/dt = (5 /times/ 10/sup -8/)((S(IV))/(1 + (H/sup +/)/K/sub a/))/sup 1/2/ K/sub a/ being the second ionization constant of H/sub 2/SO/sub 3/. The rate of loss of S(IV) was a factor of 2 faster in actual effluent/river water mixtures, likely caused by higher trace metal concentrations in these mixtures.

Alkalinity Generation and the Fate of Sulfur in Lake Sediments

Recent studies of major ion budgets of lakes have demonstrated the occurence of within-lake alkalinity generation, or acid consumption, that may represent a significant source of buffering against acid precipitation. Consumption of sulfate is associated with a major portion of alkalinity generation. Sources of alkalinity, and the capacities of lakes to neutralize sulfuric acid, corresponding to each of the probable fates of sulfur have not been discussed explicitly in earlier papers. This note was written to clarify these points.

Field studies with radioactive sulphur-labelled gysum fertiliser: IV. Recovery by pasture and soil components

Abstract In the first year of 2 separate series of field experiments investigating the fate of sulphur (S) applied as radioactive gypsum fertiliser, total mean recovery (soil and pasture) from 8 sites ranged from 30 to 99%. Harvested pasture recovery at each site comprised a small proportion of total recovery and varied from 6 to 33%, depending on stage of pasture improvement, pasture yield, time of fertiliser application, and fertiliser rate. In the absence of re-topdressing in the second year, harvested pasture recovery of S in gypsum fertiliser applied the previous year was in general lower than that in the first year and ranged from 2 to 11%. Over a 2-year period, total recovery of fertiliser S by harvested pasture was 10–40% of the initial application of 45 kg S/ha. The significance of the total recovery values was considered in relation to the effectiveness of fertiliser S applied as gypsum.

Thiocyanate Bio-oxidation Kinetics

Thiocyanates have been found in most coal conversion and coke plant effluents. Data were developed for the biological degradation rate kinetics of thiocyanate removal, and material balance information was developed for the fate of sulfur and nitrogen resulting from such bio-decomposition of aqueous thiocyanates. Based on both batch and continuous culture experiments utilizing an “activated sludge” type of system with strictly thiocyanate degrading organisms, the specific utilization rate for SCN degradation was found to follow a substrate inhibition biokinetic relationship.

鉄鋼の大気暴露さびに関する研究 (第2報)

The behavior of sulfur dioxide on low-alloy weathering steel and high strength steel (SM 50) has been clarified as to the rate of sulfate formation in the rust and its removal by water treatments. The rate of sulfate formation can be obtained by exposing steels rusted by pre-exposure to an industrial atmosphere for various periods up to two years to a radioactive SO2 environment for a few days and by determining the radioactivity of the formed sulfate. The rate of dissolution of the radioactive sulfate is determined either by immersion in distilled water or by spraying tap water on the surface.The results show that the rate of sulfate formation is lower on weathering steels and on steels pre-exposed to the atmosphere for longer periods. The tendency is in parallelism with the variation of the corrosion rates in the atmosphere with respect to steel composition and exposure time. The amount of dissolved sulfate is less for weathering steels but the percentage is almost the same regardless of steel composition.The fate of sulfur contained in steel has also been studied. In absence of copper, sulfur changes to sulfate and accumulates in rust in the course of atmospheric corrosion, but the presence of copper drastically reduces the sulfate formation.The material balance of sulfate in rust mins is considered and a mechanism of corrosion resistance of weathering steels in connection with the behavior of sulfate is discussed.

THE SULPHUR CYCLE IN GRASSLAND SOILS

In well drained grassland soils, most of the sulphur occurs in the organic matter and the average C : N : S ratio in the A horizon of normal soils is probably 100 : 8 : 1. In the absence of outside sources of sulphur, grasses in a grass/legume association would be almost completely dominant as they compete intensively with legumes for sulphur and could utilise almost all the mineral nitrogen and sulphur made available by the mineralisation of the organic matter. Legumes are thus dependent on outside sources of sulphur without which they will fix little nitrogen. The amount of sulphur needed will depend on the factors governing the amount of nitrogen fixed—climate, species, soils, management—it will be roughly a tenth to a fifteenth of the nitrogen fixed and will vary between 1–2 lb. per acre where the only addition of nitrogen to the soil is from rain or by non‐symbiotic fixation to about 60 lb. per acre under the best New Zealand pastoral conditions. In the absence of fertiliser sulphur, the atmosphere is the most significant, but a highly variable, source. An interesting situation arises in New Zealand where in one rather vigorous climatic zone where nitrogen fixation by legumes is limited to about 100 lb. nitrogen per acre per annum, so little sulphur comes from the atmosphere (probably less than 1 lb. per acre) that sulphur must be applied to enable clovers to make any appreciable growth. Under more favourable conditions where clovers may fix 600 lb. nitrogen per acre it is calculated that some 50 lb. of sulphur is obtained from natural sources and further responses may be obtained from fertiliser sulphur. Less sulphur may be needed when grass/legume associations are grazed than when they are cut for conservation, owing to the retum of sulphur in the urine—but much must depend on which system of utilisation most depresses clover growth and nitrogen fixation. The fate of sulphur when herbage is grazed is closely parallel to that of nitrogen; most of it is excreted in the urine as sulphate. Sulphate (even if applied as gypsum) may be readily lost by leaching from the A horizon and care must be exercised in the choice of forms of sulphur, rates and times of application.

Alanine and taurine formation from injected cysteine in the rat.

THE pathways for cysteine metabolism have been studied intensively, and a great deal is known about the many reactions which lead to the formation of sulphate. Most of the studies on cysteine have been mainly concerned with the fate of sulphur; but relatively few experimental results exist concerning the fate of the carbon chain. Recently, Fromageot and Chatagner1 have furnished proof of the existence of an enzyme, desulphinicase, in liver of rabbits. This enzyme is capable of liberating sulphurous acid from L-cysteine sulphinic acid. They considered the latter compound to be the most important intermediate in the conversion of organic sulphur to inorganic sulphur; they assumed that the splitting of sulphurous acid from L-cysteine sulphuric acid gave alanine as an intermediate. The formation of alanine from cysteine sulphinic acid has been demonstrated in rabbit liver extracts2.

Reclaiming Agents for Synthetic Rubber

Abstract Some highly alkylated phenol sulfides have proved to be among the most active reclaiming agents for GR-S and other synthetic rubbers. A study has been made of the activities of these materials as related to molecular structure and to the fate of sulfur during the reclaiming process. The nature and mechanism of the chemical reactions taking place during the reclaiming of natural and synthetic rubbers have been discussed in the light of the results obtained.

Lay Educational Activities of a District Dental Society

Because of its low cost and environmental compatibility, Fe-based oxygen carriers are now being considered as an attractive option for chemical-looping combustion (CLC) applications. In this work, a synthetic Fe-based oxygen carrier made by impregnation using Al2O3 as support was evaluated with respect to gas combustion in a 500 Wth CLC continuous unit using CH4 as fuel during long-term operation. Furthermore, a study on the fate of sulfur during CH4 combustion was carried out with this oxygen carrier.During the experimental tests, it was observed that an increase in the oxygen carrier-to-fuel ratio (φ) produces an increase in the combustion efficiency, reaching full gas combustion at φ values 2 1.5. In addition, the presence of sulfur in the fuel gas did not affect to the combustion efficiency, independently of the amount of sulfur in the gas stream in the range of 700 to 2000 vppm H2S. However, the attrition of this oxygen carrier was higher than other materials used in CLC.Therefore, it can be concluded that the synthetic Fe-based oxygen carrier developed in this work was highly reactive and sulfur resistant and it can be considered as a suitable oxygen carrier for CLC with gaseous fuels that contain sulfur when the attrition behavior was improved.