Papers by Keyword: SO₂

Abstract: Air pollution causes health problem. The paper simply analyzed the changes of air quality in the Yuxi city urban area from 2006 to 2012. In the Yuxi city urban area between 2006 and 2012, SO₂ levels increased about 43.9 percent; NO₂ levels increased about 13.3 percent; PM10 levels in 2012 decreased about 1.5 percent. By evaluating the air quality in the Yuxi city urban area, the results showed that air quality index was the maximum in 2009, and the quality of the air in Yuxi became worse from 2006 to 2012, air pollution in 2009 was the heaviest between 2006 to 2012. After adopting P.R.C EPA air quality standards (GB3095-2012) in 2013, the first air pollutant in Yuxi is PM₁₀, and then it is SO₂ among SO₂, NO₂ and PM₁₀.Much should beend done to reduce the amount of PM₁₀ and SO₂ released.

Abstract: In this paper, Fe²⁺、Mn²⁺、Zn²⁺、Al³⁺ were joined in the biological trickling filter circulation fluid. The result indicated that catalyzed oxidation and the biological methods simultaneously purified SO₂ and NOx of the flue, the flow amount of import gas was more obvious than the other SO₂ and NOx gas purification effect influence. The SO₂ and NOx purification mechanism of aqueous catalyzed oxidation and biological law was discussed.

Abstract: Using input-output model, this paper calculates the emission coefficients of SO₂ of China’s industry and emission of SO₂ embodied in international trade between 2005 and 2010. Furthermore, the paper analyzes the effects of technical factor, trade scale and trade structure. The emission of SO₂ embodied in export exceeds the SO₂ embodied in import, and both SO₂ emission of export and import declined during 2005-2010. The effect of technical on the emission is greater than that of trade scale; and the effect of trade structure is smaller.

Abstract: To study migration and transformation of sulfur species in oxyfuel combustion, the study attempts to analyze distribution of sulfur compounds with thermodynamic equilibrium. Results show that sulfur-containing gases predominantly are SO₂ and SO₃, the maximum thermodynamic equilibrium concentration of those in oxyfuel combustion respectively increase by 3.4 and 4.5 times compared with the conventional combustion. Furthermore, SO₂ gas formation rate decreases while SO₃ increases under oxyfuel combustion. Sulfur-containing gases are generally more sensitive to temperature and excess air coefficient. The amount of sulfur compounds significantly increases in oxyfuel combustion.

Abstract: For study on SO2 and NO emission characteristics of circulating fluidized bed boiler experiments were carried out in a 300MW circulating fluidized bed boiler. In these experiments, the variables were the amount of limestone and bed temperature. While conducting the test, the reasons for the changes in emission were analyzed, and some advices about combustion adjustment were proposed.

Abstract: Taking August Grape as material, studied on the effect of 1000, 500 and 100 μL/L SO₂ fumigation treatments on postharvest quality and SO₂ residue of fruit stored under 0 °C. The results indicated that after 90 days of storage, all treatment could decrease the decay rate and bleaching. The 500 μL/L SO₂ fumigation treatment showed an ability to significantly inhibit decreasing of vitamin C content. The SO₂ residue in grape pulp treated by 500μL/L and 100 μL/L of SO₂ were 8.56 mg/kg and 6.03 mg/kg respectively which under the FDA safety standard (10 mg/kg) after 90 days storage, while the SO₂ residue in 1000 μL/L SO₂ fumigation treatment samples was 14.36 mg/kg which beyond the FDA safety standard.

Abstract: Taking red grape as material, studied on the effect of SO₂ interval fumigation treatments on color and antioxidant of red grape, which is stored under 0 °C. The concentration of sulfur dioxide as 0%(CK), 3%(TR1), 5%(TR2) and 8%(TR3) respectively and keep one-hour. The results indicated that TR2 showed a remarkable ability to inhibit decreasing of Vitamin C content, and 52.3% higher than CK, and SO₂ residue is under the FDA standard. This study showed that 5% SO₂ fumigated for one hour is the best treatment, and keep the grape storage quality significantly.

Abstract: NO reduction by iron was conducted in a one-dimensional ceramic tubular reactor at 300 - 1100 °C in N₂ and simulated flue gas atmosphere with 0.4% methane and 0.01%~0.04% SO₂. The evolution of metallic iron was investigated by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and energy dispersive spectrum (EDS) methods. The results showed that SO₂ did not place negative effect on NO reduction by iron. XRD patterns showed that FeS was formed when there was SO₂ in the flue gas. The iron oxides were FeO and Fe₃O₄ when methane was not and was used as reducing agent respectively. Rough and raised surface making up of a series of round smooth juts was formed over the iron surface after reaction with NO in N₂ atmosphere when there was 0.04% SO₂. Porous surface consisting serried particles was formed when methane was used as reductant. White attachments were found locally on the iron surface when SO₂ existed in the flue gas, which was proved by EDS analysis to be FeS.

Abstract: The mainly pollutant from coal-fired power plants are SO₂ and NO_X. Equipments of desulphurization and denitrification step by step are expensive and have a lower efficiency. Comparing with them, Combined Removal of SO₂ and NO_X technology have great advantages, such as, the simplified complication, better operation property, lower cost and less using area. So Combined Removal of SO₂ and NO_X in one system become the keystone in the research of cleaning technology .On the base of looking up a lot of references, this paper makes a detailed introduction about Combined Removal of SO₂ and NO_X technology lately in China and other countries, including the removal principle, the mainly advantages and defects, the present situation and the application of technology. The contrast of economic and technical standard is given .Through analysis, synthesis and comparison of two kinds of technology-Combined Removal of SO₂/NO_X in boiler and in flue gas, the key of research in future is found out. These contents can reference in improvement and exploiture of technology later.

Abstract: Five kinds of powder activatedcarbons were studied to investigate the removal of SO₂ from flue gasin a fixed bed reactor. The fractal dimension of activated carbon was determined by N₂ adsorption isothermat 77Kand SO₂ adsorptioncapacity was correlated with thefractal dimension. The results show thatthe activated carbons prepared from different precursors by differentactivation methods have different fractal dimension. Big differences in SO₂ adsorption capacity are found between fivekinds of activated carbons. SO₂ adsorption capacity increases with the fractaldimension increasing. The results indicate that the fractal dimension could be used as a indicator of SO₂removal capacity on powder activated carbon.