Advanced Materials Research Vols. 724-725

Abstract: Effect of by-products from wet-oxidation explosion, such as formic acid, acetic acid, and furfural on the growth and fermentation, glycolysis and energy metabolism, cytomembrane integrality of Saccharomyces cerevisiae were studied. The results showed that the maximum tolerated concentra tion of S. cerevisiae was 1.8 g/L formic acid , 6.0 g/L acetic acid,2.5g/ furfural, respectively. The inhibition strengths of the typical inhibitors to ethanol fermentation were in the order of formic acid , acetic acid , furfural. When the concentration of these typical inhibitors is 1×IC₈₀ , acetic acid has the minimum impact on glycolysis and energy metabolism . When the concentration of these typical inhibitors was 2×IC₈₀, furfural had minimum impact on glycolysis and energy metabolism. However , formic acid can inhibit strongly the glycolysis and energy metabolism of Saccharomyces cerevisiae with any concentration . When compared with ethanol, the impact of these typical inhibitors on S. cerevisiae's cytomembrane integrality was not very significant. When the concentration of these typical inhibitors varied from 1×IC₈₀ to 3×IC₈₀ , the results of the leak of Mg²⁺ was 11%-20% formic acid, 5%-12% acetic acid, 4.5%-8.4% furfural, respectively. However, the result of ethanol that leaded to the leak of Mg²⁺ was 55%.

Abstract: Having comparison test research of economy and emission characteristics of biodiesel under different fuel supply advance angle on L16-type single cylinder diesel engine. The results show that the diesel engine has good effective thermal efficiency and economy with the fuel supply advance angle at 17°CA-BTDC; CO emissions basically increases with the decrease of fuel supply advance angle; NOx emissions increases with the fuel supply advance angle; THC emissions show not obvious and complex variation trend with the change of fuel supply advance angle, but the magnitude of the overall change is not obvious; with the decrease of fuel supply advance angle, Soot emissions increase first and then decreases.

Abstract: This paper illustrates the experimental results of co-gasification of biomass and coal in an intermittent fluidized bed reactor, aiming to investigate the effects of gasification temperature (T) and steam to biomass mass ratio (SBMR) on the composition, yield, low heating value (LHV) and carbon conversion efficiency of the product gas. The results show that H₂-rich gas with a high LHV is generated, in the range of 12.22-18.67 MJ/Nm³, and the H₂ content in the product gas is in the range of 28.7-51.4%. Increases in temperature lead to an increase in CO and H₂ content. The H₂/CO molar ratio in the product gas is close to 1 at temperature above 925 °C. With steam addition, the H₂ content increases gradually, while the content of CO increases first and then decrease correspondingly. The molar ratio of H₂/CO is close to 1 with the smallest supplied amount of steam addition (SBMR =0.4).

Abstract: The operation of a 1Mt/a gasoline and diesel hydrofining unit was performed through some energy-saving optimization. The process improvement measures include: ① Change the blending process of the recycle stock; ② Improve the thermal efficiency of the reaction part; ③ Decrease the energy consumption of the fractionation reboiler part. According to the process improvement measures above, 560 tons of standard coal per year were expected to be saved for the company. They are also beneficial for the safe operation of the apparatus.

Abstract: In this paper, a novel chemical-looping process is developed for converting sulfur dioxide (SO₂) in the flue gas generated from industries to elemental sulfur using Ca-based oxygen carriers. The system is mainly composed of a bubbling bed gasifier, a bubbling bed reactor and a circulating fluidized bed reactor. The high-purity sulfur vapor can be obtained from the reaction between SO₂ and calcium sulfide and then be cooled into solid sulfur particles. From the thermodynamic analysis, the reactions between CaS and SO₂ is much more easier to reach equilibrium than Claus reaction between H₂S and SO₂. When the temperature ranges from 500 to 600 °C, the major sulfur vapor is diatomic sulfur vapor while the solid product is mainly CaSO₄, representing the regenerating of the oxygen carrier. In the system, the required heat in the coal gasification comes from the strongly exothermic oxidation of oxygen carrier, by circulating the oxygen carrier particles in the system. The effects of reacting temperature, SO₂/CaS molar ratio on the yield of sulfur particle and conversion of SO₂ to elemental sulfur are all discussed. The favorable temperature of the reactor to generate elemental sulfur should be between 500 and 600 °C.

Abstract: Kinetics is the study of rates of chemical processes, which includes investigations of how different experimental conditions can influence the speed of a chemical reaction and the reactions mechanism. In this paper, the influences of several parameters including particle size and mass of copper-based oxygen carrier, reaction gas flow rate and temperature on the conversion rate of oxygen carrier in chemical looping combustion was investigated. The results of experiment reveal that the conversion rate of oxygen carrier is influenced by the reaction temperature, mass of the oxygen carrier and the reaction gas flow rate. The conversion rate of oxygen carrier is improved with decreasing the mass of the oxygen carrier and increasing the reaction gas flow rate within a certain extent in the chemical looping combustion process. The particle size has very little effect on the conversion rate, and 800 °C is an advisable reaction temperature for chemical looping combustion process of copper-based oxygen carrier with methane and air.

Abstract: 60wt%Fe₂O₃/Al₂O₃ oxygen carriers were prepared by different methods and characterized by means of XRD, H₂-TPR, infrared gas analyzer. The effects of preparation methods on the structure and activity of Fe₂O₃/Al₂O₃ oxygen carriers for chemical looping combustion of methane were also investigated. The factors on the selectivity of CO₂ in the chemical looping combustion process at different reaction temperatures were discussed. Methane can be quickly converted to CO₂ and H₂O with high selectivity at 850°C for 15 min. After redox cycling in alternant methane/air atmosphere for 30 times, the formation of CO₂ was enhanced, indicating higher activity of oxygen carrier after the redox experiment.

Abstract: A bacterial cellulose-alginate composite sponge (BCA) was developed for use as a cell carrier in ethanol fermentation. Its hydrophilicity was improved by oxygen plasma treatment. Due to the etching effect in plasma application, the external surface roughness of treated BCA was increased, resulting in a decrease of advancing water contact angle. However, oxygen plasma treatment might not be able to create sufficient hydrophilic functional groups on the internal pore surface of BCA, where the yeast cells would be immobilized during fermentation. As a result, under batch fermentation, no significant difference in ethanol production obtained from the immobilized cell systems using the treated and untreated BCAs.

Abstract: Biodiesel has been receiving significant attention as a renewable and nonpolluting fuel. In this study, oleic acid and bioalcohols (ethanol and butanol) were used as substrates for biodiesel production. The reactions were performed in a solvent-free system using immobilized lipase (Novozym 435) as biocatalyst in a batch esterification process. The optimal conditions were 45°C, oleic acid to alcohol molar ratio of 1:2, Novozym 435 loading at 5% based on oleic acid weight and 250 rpm, in which the free fatty acid (FFA) conversion at 91.0% was obtained after 12 hours of the reaction.

Abstract: Chemical-looping combustion is a promising method to realize the near zero emissions of CO₂ without any excessive energy penalty. In this paper the reactivity behavior of calcium sulfate (CaSO4) as oxygen carrier (OC) with coal chars are investigated. After the impregnation of nickel ions or iron ions, the reacting behaviors of the OC are remarkably promoted comparing with that before the impregnation. The high impregnation of nickel ions or iron ions is beneficial to the reactivity of the OC, especially in the first half of the reaction. After the reaction of fresh CaSO₄ with coal chars, the solid products are merely CaS. In addition, the solid products of Ni-impregnated OC consist mainly of CaS, CaO and Ni₃S₂ while the solid products of Fe-impregnated OC are composed of Fe₃O₄ and CaS.