Addition Of SO2 Research Articles

Effects of SO2 on CO2 capture using a hollow fiber membrane contactor

Membrane gas absorption technology is a promising alternative to conventional technologies for the mitigation of acid gases. In this study, with a polypropylene (PP) hollow fiber membrane contactor as absorber and a packed column as stripper, the influence of SO2 on the CO2 capture from coal-fired power plant flue gas was investigated in an absorption–desorption experimental set-up using aqueous monoethanolamine (MEA) as the absorbent. The experimental results showed that the MEA loss per ton captured CO2 increased with the addition of SO2, resulting in sharp decreases in CO2 removal efficiency and mass transfer rate of CO2 after initial several days of operation. This tendency is mainly attributed to the promotional effect of SO2 on the degradation of MEA by the formation of sulfate. Thus, it is necessary to regenerate MEA using a reclaimer in this case. The respective SO2 concentrations at the outlets of absorber and stripper remained constant values of 24 and 120ppb throughout the operation although the CO2 removal efficiency decreased dramatically with time. This co-capture of CO2 and SO2 could play an important role in further desulfuration, thus alleviating the burden of desulfuration to some extent and benefiting the subsequent CO2 purification and storage. More progresses are greatly needed in high-efficiency and stable absorbents, high-efficiency reclaimer, and methods to reduce MEA loss by evaporation.

UV–vis irradiation: An alternative to reduce SO2 in white wines?

Ultraviolet–visible irradiation was tested as an innovative technology that can help reducing the amount of sulfur dioxide used in white wine manufacturing. In addition, the effects of must freezing before processing were also investigated. Musts from Xarel·lo and Parellada varieties were vinified without any protective treatment, with a standard amount of SO2 addition or after an irradiation step. The results showed that UV–vis irradiation of must was able to prevent wine from spoilage in the same degree as SO2, without changing other quality parameters such as pH, tartaric acid and alcohol content. However, a residual addition of SO2 would be required in order to completely inhibit polyphenol oxidase activity. Moreover, the obtained changes in wine color parameters led to the conclusion that further optimization of the irradiation process is required before its implementation. Must freezing was shown to have some influence on quality parameters of Xarel·lo wines, but not in those from Parellada.

Gas-phase elemental mercury removal in a simulated combustion flue gas using TiO2 with fluorescent light

A previously proposed technology incorporating TiO2 into common household fluorescent lighting was further tested for its Hg0 removal capability in a simulated flue-gas system. The flue gas is simulated by the addition of O2, SO2, HCl, NO, H2O, and Hg0, which are frequently found in combustion facilities such as waste incinerators and coal-fired power plants. In the O2 + N2 + Hg0 environment, a Hg0 removal efficiency (ηHg) greater than 95% was achieved. Despite the tendency for ηHg to decrease with increasing SO2 and HCl, no significant drop was observed at the tested level (SO2: 5–300 ppmv, HCl: 30–120 ppmv). In terms of NO and moisture, a significant negative effect on ηHg was observed for both factors. NO eliminated the OH radical on the TiO2 surface, whereas water vapor caused either the occupation of active sites available to Hg0 or the reduction of Hg0 by free electron. However, the negative effect of NO was minimized (ηHg > 90%) by increasing the residence time in the photochemical reactor. The moisture effect can be avoided by installing a water trap before the flue gas enters the Hg0 removal system. Implications: This paper reports a novel technology for a removal of gas-phase elemental mercury (Hg0) from a simulated flue gas using TiO2-coated glass beads under a low-cost, easily maintainable household fluorescent light instead of ultraviolet (UV) light. In this study, the effects of individual chemical species (O2, SO2, HCl, NO, and water vapor) on the performance of the proposed technology for Hg0 removal are investigated. The result suggests that the proposed technology can be highly effective, even in real combustion environments such as waste incinerators and coal-fired power plants.

Pilot-Scale Study of CO2 Capture by CaO-Based Sorbents in the Presence of Steam and SO2

Calcium looping cycles require an oxy-fired calciner burning coal for sorbent regeneration. Thus, in addition to O2 and CO2, the flue gases will include both steam and SO2, and similarly, carbonation of real flue gases will occur in the presence of steam. However, to date, most research has been done without either of these two gaseous components present. Here, batch combustion experiments were performed in a pilot-scale fluidized-bed reactor to study the effects of steam and SO2 addition on CO2 capture by limestone-based sorbents calcined under oxygen-enriched air and oxy-fuel conditions. The initial fast kinetically controlled CO2 capture stage was dramatically reduced when the sorbent was calcined at realistic temperatures in the presence of SO2. This is attributed to both greater sintering due to higher local calcination temperatures required by high CO2 concentrations and CaSO4 formation. By contrast, steam in the synthetic flue gas during carbonation extended the initial, high-efficiency CO2 capture...

Catching Gaseous SO2 in Cone-Type Lanthanide Complexes: An Unexpected Coordination Mode for SO2 in f-Element Chemistry

Easy come, easy go: the first molecular SO(2) complexes of the lanthanides (Ln=Sm, Eu) have been prepared. The compounds can reversibly coordinate gaseous SO(2). Concomitant with the addition and removal of SO(2), the color of the complexes changes reversibly. The structures of the SO(2) compounds could be confirmed in solution and in the solid state.

Effects of gaseous NH3 and SO2 on the concentration profiles of PCDD/F in flyash under post-combustion zone conditions

The influence of gaseous ammonia and sulphur dioxide on the formation of 2378-substituted PCDD/F on a reference flyash from a municipal waste incinerator has been investigated using a laboratory scale fixed-bed reactor. The reference flyash samples (BCR-490) was reacted under a simulated flue gas stream at temperatures of 225 and 375°C for 96h. The experiments were carried out in two series: first with simulated flue gas alone, and then with injection of NH3 or SO2 gas into the flue gas just before the reactor inlet. It was found that the injection of gaseous ammonia into the flue gas could decrease the concentration of both PCDD and PCDF by 34–75% from the solid phase and by 21–40% from the gas phase. Converting the results to I-TEQ values, it could reduce the total I-TEQ values of PCDD and PCDF in the sum of the flyash and exhaust flue gas by 42–75% and 24–57% respectively. The application of SO2 led to 99% and 93% reductions in the PCDD and PCDF average congener concentrations, respectively in the solid phase. In the gas phase, the total reductions were 89% and 76% for PCDD and PCDF, respectively. Moreover, addition of SO2 reduced the total I-TEQ value of PCDD and PCDF in the flyash and exhaust flue gas together by 60–86% and 72–82% respectively. Sulphur dioxide was more effective than ammonia in suppressing PCDD/F formation in flyash under the conditions investigated.

Sulfur dioxide oxidation induced mechanistic branching and particle formation during the ozonolysis of β-pinene and 2-butene

Recent studies have suggested that the reaction of stabilised Criegee Intermediates (CIs) with sulfur dioxide (SO(2)), leading to the formation of a carbonyl compound and sulfur trioxide, is a relevant atmospheric source of sulfuric acid. Here, the significance of this pathway has been examined by studying the formation of gas phase products and aerosol during the ozonolysis of β-pinene and 2-butene in the presence of SO(2) in the pressure range of 10 to 1000 mbar. For β-pinene at atmospheric pressure, the addition of SO(2) suppresses the formation of the secondary ozonide and leads to highly increased nopinone yields. A complete consumption of SO(2) is observed at initial SO(2) concentrations below the yield of stabilised CIs. In experiments using 2-butene a significant consumption of SO(2) and additional formation of acetaldehyde are observed at 1 bar. A consistent kinetic simulation of the experimental findings is possible when a fast CI + SO(2) reaction rate in the range of recent direct measurements [Welz et al., Science, 2012, 335, 204] is used. For 2-butene the addition of SO(2) drastically increases the observed aerosol yields at higher pressures. Below 60 mbar the SO(2) oxidation induced particle formation becomes inefficient pointing to the critical role of collisional stabilisation for sulfuric acid controlled nucleation at low pressures.

The role of doped Fe on the activity of alumina-supported Pt and Pd diesel exhaust catalysts

Supported Pt and Pd are most commonly used for oxidation catalysts. They have similar and different characteristics for deactivation factors. The catalytic activity of Pt and Pd catalysts supported on γ-Al2O3 was studied in the presence and absence of H2O and SO2 during CO oxidation under simulated conditions of diesel exhaust gas. Without the addition of H2O and SO2 to the feed gas, Pd/Al2O3 had a superior catalytic activity compared to Pt/Al2O3. The addition of H2O to the feed gas strongly and negligibly affected the activity of Pd and Pt, respectively, while the addition of SO2 to the feed gas had a strong poisoning effect on the catalytic activity of both Pt and Pd catalysts. Although being the most active, Pd catalysts exhibited a strong sensitivity to water and sulfur-containing compounds. Fe was added to the Pt and Pd catalysts to introduce sulfur resistance. The addition of Fe enhanced the activity of the catalysts by suppressing the phase transition of Al2O3 to Al2(SO4)3 and by hindering metal sintering.

Yield of HO2 Radicals in the OH-Initiated Oxidation of SO2

Abstract The HO2 radical yield in the OH initiated oxidation of SO2 has been determined by direct observation of HO2 concentration time profiles following the 248 nm photolysis of H2O2/SO2/O2 mixtures. Initial OH radical concentrations have been deduced from a fit of the absolute HO2 concentration time profiles after 248 nm photolysis of H2O2 in the absence of SO2, an increase in the HO2 concentration upon addition of SO2 to this reaction mixture is observed and can be explained by a decrease of HO x -radical losses due to a faster decay of OH radicals in the presence of SO2. Simulations of theses profiles using recommended rate constants in a simple model are in agreement with an HO2-yield of 1.0 ± 0.1 from the OH initiated oxidation of SO2.

Gas-Phase Oxidation of Mercury by Bromine and Chlorine in Flue Gas

Oxidized mercury species may be formed in combustion systems through gas-phase reactions between elemental mercury and halogens, such as chorine or bromine. This study examines how bromine and chlorine species affect mercury oxidation in the gas phase. Experiments were conducted in a bench-scale, laminar, methane-fired (300 W), quartz-lined reactor, in which gas composition (HCl, HBr, NOx, and SO2) was varied. In the experiments, the postcombustion gases were quenched from the flame temperature to about 350 °C and then speciated mercury was measured using a wet conditioning system and continuous emission monitor (CEM). Bromine was shown to be much more effective in the postflame, homogeneous oxidation of mercury than chlorine, on an equivalent molar basis. The addition of NO to the flame (up to 400 ppmv) had no impact on mercury oxidation by chlorine or bromine. The addition of SO2 had no effect on mercury oxidation by chlorine at SO2 concentrations below about 400 ppmv; some increase in mercury oxidation was observed at SO2 concentrations of 400 ppmv and higher. The addition of chlorine caused minor increases in the extent of oxidation by bromine. The results of this study can be used to understand the relative importance of gas-phase mercury oxidation by bromine in combustion systems.

Electrochemical Enhancement of Nitric Oxide Removal from Simulated Lean-Burn Engine Exhaust via Solid Oxide Fuel Cells

A solid oxide fuel cell (SOFC) unit is constructed with Ni-YSZ as the anode, YSZ as the electrolyte, and La(0.6)Sr(0.4)CoO(3)-Ce(0.9)Gd(0.1)O(1.95) as the cathode. The SOFC operation is performed at 600 °C with a cathode gas simulating the lean-burn engine exhaust and at various fixed voltage, at open-circuit voltage, and with an inert gas flowing over the anode side, respectively. Electrochemical enhancement of NO decomposition occurs when an operating voltage is generated; higher O(2) concentration leads to higher enhancement. Smaller NO concentration results in larger NO conversion. Higher operating voltage and higher O(2) concentration can lead to both higher NO conversion and lower fuel consumption. The molar rate of the consumption of the anode fuel can be very much smaller than that of NO to N(2) conversion. This makes the anode fuel consumed in the SOFC-DeNO(x) process to be much less than the equivalent amount of ammonia consumed in the urea-based selective catalytic reduction process. Additionally, the NO conversion increases with the addition of propylene and SO(2) into the cathode gas. These are beneficial for the application of the SOFC-DeNO(x) technology on treating diesel and other lean-burn engine exhausts.

Effect of SO2 and CO2 additives on the cycle performances of commercial lithium-ion batteries

The effects of SO2 and CO2 additives in electrolytes on the cycle properties of liquid-state Al-plastic film lithium-ion batteries were first investigated. The experimental electrolytes were added with different amounts of SO2 and CO2. The baseline electrolyte was 1 mol L−1 LiPF6 in ethylene carbonate/dimethylcarbonate/ethyl-methyl carbonate (1:1:1, by volume), and graphite was used as anode. The main analysis tools were cycling test, rate capability, internal resistance test, low-temperature performance, and thermal stability. The results showed that both of the additives could promote to form an excellent solid electrolyte interface film on the surface of graphite anode, leading to excellent cycle performances, the capacity retentions of CO2 and S5 were 94% and 97% after 400 cycles, respectively. Besides, the results also exhibited that the electrochemical performances of internal resistance, rate capability, low-temperature performance, and thermal stability were not changed significantly by the use of SO2 and CO2 as electrolyte additives.

The effect of pectolytic enzyme treatments on red grapes mash of Vranec on grape juice yield

Laboratory and industrial trials were conducted to evaluate the effect of pectolytic enzyme treatments on red grape mash of Vranec on grape juice yields. The red grape Vranec for laboratory trials were taken from private winery “Imako vino” Stip (Macedonia) and trials were conducted in their laboratory. The red grape Vranec for industrial trials were taken from private winery “Tristo” Veles (Macedonia) and trials were conducted in their winery. The grapes were weighed, destemmed, crushed and divided in 5 liters plastic reservoirs for laboratory trials, and for industrial trials were placed in a stainless steel fermentor (4t.). All treatments were performed in doublecate. Red grape mash made from Vranec were macerated for 6 hours at 18 to 20 oC with addition of one commercial pectolytic enzyme preparation (Vinozym Vintage FCE, Rohapect VR-C and Trenolin Rot DF). After addition of SO2 (50ppm) and yeast (Saccharomyces cerevisiae) NEUTRE SC (Lallemand, 2009)(200 mg/kg grape), maceration time of 5 days (~25 oC)was applied in order to study the effect of macerating enzymes on grape juice yields. After the maceration, the pomace was removed, in the obtained 4 different variations. Pectolytic enzyme preparation was not added to control trial. All treatments were performed in duplicate. Results of laboratory and industrial trials from our experiments, gives increased on free run juice yields by 4.85%-6.35% compared with non-treated mash of control trials.

Corrosion and degradation performance of novel absorbent for CO2 capture in pilot-scale

Abstract The corrosion and degradation behavior of new blended amine absorbent specified by Toshiba were studied in the pilot plant under the condition of long-term operation. Three test campaigns of the CO2 capture were completed. One campaign was the base experiment to evaluate the thermal and oxidative degradation and corrosion character of new absorbent. Other two campaigns were operated to evaluate the influence of SO2 on the corrosion and degradation behavior of new absorbent. The results show that the SO2 removal efficiency is almost 100%. After addition of SO2 to simulated flue gas, there will be more serious amine degradation and HSS formation. The greater the SO2 concentration is, the more amine degradation and HSS formation. The point C which is outlet of the heat exchanger (rich liquid side) presents the most serious corrosion. Addition of SO2 plays an important role to form the corrosion protect films. It was difficult to form protect film and easily be destroyed at the presence of SO2 for stainless steel compared with carbon steel.

Corrosion of Aluminized and Uncoated 9–12% Cr Boiler Steels in Simulated Biomass andWaste Combustion Conditions

Coatings are seen a promising way to improve the corrosion resistance of relatively cheap power plant steels to enable higher steam temperatures than currently in use. In this research, 9–12% Cr steels P91 and HCM12A are coated with aluminium diffusion coating by a slurry method and exposed for 336 hours at 833 K and 883 K to atmospheres containing varying amounts of O2, H2O, HCl and SO2. Corrosion behaviour of the coated steels is compared to that of those steels in an uncoated condition. Characterization is performed by weighing, SEM + EDS and XRD. The results show that corrosion resistance of P91 and HCM12A is significantly improved by the aluminium diffusion coating at high temperatures in atmospheres containing HCl and SO2. The corrosion rate of the aluminized specimens slightly increases with increase in test temperature but remains virtually the same irrespective of the composition of the atmosphere. On the other hand, the corrosion rate of the uncoated specimens is dependent on both the atmosphere and the temperature. The steels undergo active oxidation that results in formation of non-protective, thick and layered scales in HCl containing atmospheres. SO2 addition slightly decreases the corrosion rate although it is anyway higher than that in SO2 containing atmosphere without HCl.

Kinetic investigation of the SO2 influence on NO reduction processes during methane reburning

AbstractThe reburning technique is an economical and highly efficient method for the reduction of NOx (nitrogen oxides) emissions. The University of Leeds (UK) proposed mechanism was used to investigate the effect of SO2 on the NO reduction during methane reburning in a plug flow reactor (CHEMKIN model) and compared with Glarborg's experimental data. The computational and experimental results show good agreement when there is no SO2 addition, and the highest NO reduction is obtained at the optimal air/fuel ratio 0.8. With SO2 addition, the optimal air/fuel ratio increases from 0.8 to 0.87 with an increase of SO2 concentration from 0 to 3000 ppm at a temperature of 1300 K. Under the fuel‐lean condition, the addition of SO2 slightly enhances the reduction of NO during methane reburning. Under the fuel‐rich condition, SO2 addition inhibits the reduction of NO when the air/fuel ratio is in the range of 0.65–1.0. However, when the air/fuel ratio is less than 0.65, then SO2 addition has negligible effect on NO reduction. The reaction mechanisms that influence the effect of SO2 on NO reduction were determined by the main controlling elementary reactions obtained from sensitivity analysis. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.

Multifactorial analysis of acetaldehyde kinetics during alcoholic fermentation by Saccharomyces cerevisiae

Acetaldehyde is the terminal electron acceptor in the alcoholic fermentation by Saccharomyces cerevisiae. Quantitatively the most important carbonyl by-product, it has relevance for ethanol production yields as well as product stabilization and toxicology. The aim of this study was to investigate the effect of various enological parameters on acetaldehyde kinetics during alcoholic fermentations. Two commercial yeast strains were tested in two grape musts and the pH, temperature, SO2 and nutrient addition were varied. All incubations had uniform kinetics where acetaldehyde reached an initial peak value followed by partial reutilization. Peak acetaldehyde concentrations and residual concentrations after 15days of fermentations ranged from 62 to 119mgl−1 and 22 to 49mgl−1, respectively. A positive linear relationship was found between peak and final acetaldehyde levels in Gewürztraminer, but not Sauvignon Blanc fermentations, where sluggish fermentations were observed. Several factors had a significant effect on peak and/or final acetaldehyde levels. SO2 addition, grape cultivar and fermentation nutrition were important regulators of peak acetaldehyde production, while final acetaldehyde concentrations were correlated with SO2 addition, grape cultivar and temperature. The results allowed to estimate the acetaldehyde increase caused by SO2 addition to 366μg of acetaldehyde per mg of SO2 added to the must. The course of the final fermentation phase was shown to determine acetaldehyde residues. Comparison of acetaldehyde and hexose kinetics revealed a possible relationship between the time of occurrence of peak acetaldehyde concentrations and the divergence of glucose and fructose degradation rates.

Determination of major volatile compounds during the production of fruit vinegars by static headspace gas chromatography–mass spectrometry method

A static headspace gas chromatography coupled to mass spectrometry (SHS–GC–MS) method was validated to determine several major volatile components during the production process of fruit vinegars. The method is simple, fast, linear in the working range, suitably sensitive, repeatable and reproducible, and has a good degree of accuracy for most of the compounds studied. Different conditions were tested in the production process of vinegars by means of double fermentation. The addition of SO2 and pectolytic enzymes produced a considerable increase in methanol and acetaldehyde, especially in strawberry purees, whereas pressing led to a loss of these volatile compounds. In the alcoholic fermentation of persimmon and strawberry purees, the Saccharomyces cerevisiae strain used had a great influence on the production of acetaldehyde and higher alcohols in wines. Considering the influence of these studied compounds in the final profile of the vinegars, our results showed that the S. cerevisiae strain isolated in this study produced the most suitable wine substrates for the production of vinegars. Moreover, semisolid fruit substrate provides better results than liquid substrate. Inoculated acetification in wood recipients yielded vinegars with a better volatile profile, as these contained higher levels of most compounds except acetaldehyde.

Distribution of δ34S and δ18O in SO2−4 in Groundwater from the Ordos Cretaceous Groundwater Basin and Geological Implications

Abstract:The Ordos Cretaceous Groundwater Basin, located in an arid‐semiarid area in northwestern China, is a large‐style groundwater basin. SO2−4 is one of the major harmful components in groundwater. Dissolved SO2−4 concentrations, and δ34S‐SO2−4 and δ18O‐SO2−4 in groundwater from 14 boreholes and in gypsum from aquifer were analyzed. Results show that SO2−4 in shallow groundwaters originates from precipitation, sulfide oxidation, and dissolution of stratum sulphate, with a big range of δ34S values, from −10.7‰ to 9.2‰, and addition of SO2−4 in deep groundwater results from dissolution of stratum sulphate, with bigger δ34S values, from 7.8‰ to 18.5‰, compared with those in shallow groundwater. This research also indicates that three types of sulphate are present in the strata, and characterized by high δ34S values and high δ18O values‐style, high δ34S values and middle δ18O values‐style, middle δ34S values and low δ18O values‐style, respectively. The δ34S‐SO2−4 and δ18O‐SO2−4 in groundwater have a good perspective for application in distinguishing different groundwater systems and determining groundwater circulation and evolution in this area.

Inactivation of wine spoilage yeastsDekkera bruxellensisusing low electric current treatment (LEC)

The objective of this study was to investigate the inactivation of a selected yeast Dekkera bruxellensis strain 4481 in red wine by application of low electric current treatment (LEC). LEC (200 mA) was applied for 60 days to a red wine, Montepulciano d'Abruzzo, in an alternative strategy to the SO(2) addition during wine storage. The LEC effect on both cell activity and microflora viability was assessed. LEC decreased significantly the survival viable cells and increased the death rate of D. bruxellensis strain 4481 yeast. A final comparison was made of the main physico-chemical parameters of the wine after the different treatments. The study suggests the importance of an appropriate LEC treatment which limits wine deterioration in terms of off-flavours synthesis. The results demonstrate that the growth of undesirable Dekkera can be inhibited by low voltage treatment; LEC was shown to be useful to prevent wine spoilage and has the potential of being a concrete alternative method for controlling wine spoilage. Wine spoilage can be avoided by preventing the growth of undesirable Dekkera yeasts, through the effective use of LEC in the winemaking process.