Absorption of sulphur dioxide by electrosprayed droplets

This paper describes and discusses experimental results on the absorption of sulphur dioxide in electrified water sprays, either when the polluted gas is treated as is or when the gas is exposed to a corona source to ionize the sulphur dioxide. The experiments revealed that an electrified spray with a charge-to-mass ratio of 50 μC · kg⁻¹ enabled the absorption rate of droplets to double, regardless of their polarities. Corona charging gave rise to an increase in the SO₂ depletion rate over the scrubber wall, while negligible effects appeared on the actual droplets absorption rate. These findings suggested that faster absorption rates mostly, though not uniquely, depend on the modifications on the morphological and interfacial properties of the sprayed droplets induced by the free electric charge imposed on their surface. Conversely, the absorption rates were negligibly affected by the electrical interactions between droplets (either charged or uncharged) and the sulphur dioxide ions/radicals originating from the corona source.     

柠檬酸钠法生产液体二氧化硫

介绍10kt/a柠檬酸钠法液体二氧化硫生产装置的工艺流程和运行情况。一年多来,设备运行正常,工艺参数稳定,实现了连续稳产和低耗,取得了明显的经济效益。     

三氧化硫-硫磺法生产液体二氧化硫

介绍了用发烟硫酸中的SO3与硫磺反应生成二氧化硫的试验情况。根据试验结果设计采用液体三氧化硫和液体硫磺生产液体SO2的装置,介绍了其工艺流程及生产运行情况。对三氧化硫-硫磺法生产液体SO2与常用其他三种方法进行了比较,对生产成本进行了分析。生产出的液体SO2残渣质量分数小于或等于0.006%,水分质量分数小于或等于0.01%,完全满足各行业对液体SO2的质量需求。     

Modelling of absorption of sulphur dioxide with aqueous sodium carbonate

Absorption is a suitable process for the purification of air from gaseous substances such as sulphur dioxide. To decide upon the dimensions of a gas purification column with valve grid trays, the coefficient of mass transfer and the kinetics of the absorption steps were determined. The overall reaction kinetics were determined in a wetted-wall absorber. Gas concentrations of 10 mg m⁻³ were obtained.     

Sorption of sulphur dioxide by paper

Sulphur dioxide is sorbed by paper and slowly converted to sulphuric acid; the presence of this severely reduces the useful life of the material. The sorption (‘pick-up’) of sulphur dioxide has been investigated for a representative range of papers for exposures lasting many months at concentrations approaching those found in polluted urban atmospheres. It was found that the relative humidity does not significantly affect the long-term pick-up rate and that this rate remains constant for prolonged exposures, being proportional to the square root of the gas phase sulphur dioxide concentration. Rosin size increases markedly the long-term rate while certain other paper additives, e.g. Turkey Red Oxide and Anatase, have no such effect.     

二氧化硫的加压转化

介绍了以液体SO2为原料生产用作磺化剂的气态SO3的工艺过程。采用硅胶干燥法得到加压干燥空气。汽化的液体SO2经加压干燥空气稀释后进行三段一次转化生产气态SO3。由于SO2经加压干燥空气稀释后的氧硫比较高、压力较大,一段转化率过高,催化剂存在烧毁的危险。为此,根据SO2转化的化学平衡,分析了温度、压力和起始氧浓度对平衡转化率的影响,确定了进转化器气体φ（SO2）12%～16%,压力0.18～0.20MPa,装置投运后,能长期稳定运行,转化率为97%左右。     

二氧化硫排放法规

自20世纪70年代二氧化硫被确定为严重的环境污染物以来,世界各国就开始逐步立法,以减少二氧化硫的排放。介绍了欧洲、美国、加拿大、中国、印度等二氧化硫排放法规的立法历程及现状,重点讨论了各国燃煤电厂的二氧化硫排放限值。     

Electrogenerative oxidation of sulphur dioxide

Possible applications of a galvanic synthesis of sulphuric acid from sulphur dioxide and oxygen are discussed and preliminary results for a laboratory-scale reactor are presented. The use of active, fuel-cell electrodes enables relatively large current densities to be obtained at low cell voltages.     

Conversion of caking coal into non-caking coal by treatment with sulphur and sulphur dioxide

The effects on the caking properties of coals of reaction between the coals and S₈ and SO₂, have been studied. Caking coals (Akabira, Shinyubari, Zollverein, Indian Ridge, and Big Ben) lose their caking properties when treated with S₈ above 200 °C. For Shinyubari coal the crucible swelling number decreases from $\text{8}\text{1}\text{2}$ to 2 with treatment temperature of 235°C in which 5% of S is incorporated into the coal. The decaking of coal is attributed to thio-ether cross-linkages. Caking coals also lose completely their caking property when reacted with SO₂ at 170 °C. The decaking action of SO₂ is attributed to oxidation of coal in which ether cross-linkages are formed.     

冶炼烟气中二氧化硫的催化还原

自热熔炼镍冶炼工艺产生的烟气ψ(SO2)为20％或更高,可用于生产元素硫。该技术的基本原理是用天然气还原二氧化硫,在还原阶段采用催化剂有可能大大提高效率。     

Adsorption of sulphur dioxide on coal

A study was made of the feasibility of using coal as an adsorbent material for the removal of sulphur dioxide from stack gases emitted to the atmosphere by different industries. From preliminary results, it would appear that coal is to be favoured by a raw materials/cost-effectiveness ratio of 2:1. The work shows semi-quantitatively that the adsorptive capacity of sulphur dioxide on coal varies slightly from one coal to another and that when coal is used and re-used through numerous (?40) cycles, its effectiveness as an adsorbent for sulphur dioxide is not greatly reduced. Moreover, this research supports the view that the heating value, ash, sulphur content, etc. of most types of coal changes only slightly after repeated usage as an adsorbent for sulphur dioxide. If, as these findings indicate, coal can initially be used as a sulphur dioxide adsorbent prior to its use as a fuel, economic potential for commercial applications should be enhanced. Empirical equations, developed to correlate the adsorption-desorption characteristics of different coals, can be used as a basis for prediction and comparison by future investigators to further explore this research.     

Sorption of sulphur dioxide by indoor surfaces II. Wood

The sorption of sulphur dioxide by untreated wood samples has been investigated at a concentration of 90 μg/m³ by use of ³⁵SO₂. The softwoods sorbed less sulphur dioxide than the hardwoods and the sites of sorption were different in each class. Most of the sorbed sulphur dioxide was found in the outermost 0.05 mm of each sample and a large portion of it was water-soluble. The possible role of sulphur dioxide in the weathering of woods is discussed.     

Sorption of sulphur dioxide by indoor surfaces I. Wallpapers

The sorption of sulphur dioxide by PVC wallcoverings and conventional wallpaper samples has been measured at a maximum sulphur dioxide concentration of 150 μg/m³ by use of ³⁵SO₂. The sorption was found to be influenced by the surface finish and design pattern of the wallpapers. Sweat deposits on the samples also influenced the pattern of uptake. The conventional wallpapers showed a greater uptake than did PVC wallcoverings in all cases.     

Absorption of chlorine into aqueous sodium carbonate solutions and desorption of carbon dioxide

The absorption of pure chlorine into aqueous sodium carbonate solutions accompanied by the desorption of carbon dioxide was studied both theoretically and experimentally. The absorption rates of chlorine and the desorption rates of carbon dioxide were measured at 25°C using a baffled agitated vessel operated batchwise. The experimental results were analyzed with the chemical absorption theory based on the Lévěque model. The measured absorption and desorption rates were in good agreement with the theoretical predictions.     

Equilibrium studies of the direct reduction of sulphur dioxide by coal

The direct reduction of sulphur dioxide to elemental sulphur using coal has been studied utilizing models that simulate thermodynamic equilibrium. Comparison has been made between the computer models and process results. The results of the analysis indicate a discrepancy which may be attributable to the manner in which samples are taken for analysis. The actual process may be in thermodynamic equilibrium.     

Wetting properties of the sulphur electrolyte in sodium — sulphur batteries

In the sulphur electrode of sodium-sulphur cells, carbon surfaces (generally as yarns or felts) are used as current collectors. During the charging cycle, oxidation of the molten polysulphides results in sulphur as a second (immiscible) phase. If sulphur has preferential wetting properties, an insulating sulphur layer may be established. A technique for wetting measurements with the molten sulphur electrolyte at 330° C is described. The wetting properties of molten sulphur and molten polysulphides were investigated with both untreated and metal oxide treated carbon surfaces as substrates. Results are reported for felts with Fe, Ni, Co, Cr, Al (as oxides), and with H₂0, NaOH, Na₂SO₄ and Na₂S₂O₃ as impurities in the fluid electrolyte.Presented at the 30th meeting of the International Society of Electrochemistry at Trondheim, Norway, August 1979.     

Electrochemical sulphur dioxide oxidation with platinum-aluminum electrocatalysts

Platinum-aluminum electrocatalysts supported on carbon black were investigated for electrogenerative sulfur dioxide (SO₂) oxidation in hybrid type, liquid-phase SO₂/O₂ cells. Incorporation of aluminum with platinum electrocatalysts on carbon resulted in an electrocatalytic activity increase for S02 oxidation over the whole investigated range (1–30 at % aluminum). Significant synergistic effect from aluminum was observed when even a small amount, as little as 1 at %, was incorporated in the platinum. A maximum 68 % improvement was obtained when 10 at % aluminum was incorporated in the platinum. Results of an ESCA study and electrochemical platinum surface area measurement supported the hypothesis of an electronic interaction between platinum and aluminum.     

Oxygen absorption in aqueous sulphur dioxide solutions

An improved kinetic model of catalytic oxidation of tetravalent sulphur in aqueous solutions has been suggested, based on oxygen absorption experiments carried out in a stirred tank with a plane interface. The model comprises a chemical network of catalyst (manganous soluble salt) transformations and a set of step rate equations with the appropriate kinetic constants determined. It indicates the possible enhancement of tetravalent sulphur oxidation by applying conditions of the manganous dimer maximum concentration.