Chenghua Xu

Glycerol steam reforming over Ni/γ-Al2O3 catalysts modified by metal oxides

The metal oxides modified Ni/γ-Al2O3 catalysts for glycerol steam reforming were prepared by impregnation. Characterization results of fresh catalysts indicated that the molybdates modification abated the acidity and the stronger metal-support interaction of Ni/γ-Al2O3 catalysts, leading to a stable catalytic activity. Especially, NiMoLa-CaMg/γ-Al2O3 (NiMoLa/CMA) catalyst exhibited no deactivation along with glycerol complete conversion to stable gaseous products containing 69% H2, 20% CO and 10% CO2 during time-on-stream of 42 h. TPO of spent Ni/γ-Al2O3 catalysts modified by different components showed that the carbon deposit on acidic sites and NiAl2O4 species led to catalysts deactivation. A lower reforming temperature and a higher LHSV and glycerol content were helpful to the production of syngas from GSR over NiMoLa/CMA; the reverse conditions would improve the formation of H2.

Simulation Studies on Limestone Dissolution with Organic Acid Additives in Limestone-Based Flue Gas Desulfurization

The effects of organic acids on limestone dissolution rate were investigated by pH-stat method. The results showed that the dissolution rate of -60+80 mesh with 50 mmol/L acetic acid was the same as that of -300 mesh without organic acid. With the same concentration of acetic acid and benzoic acid, the former had stronger ability than the latter to increase the limestone dissolution. By increasing concentration of organic acid added, the granular limestone can be used as a desulfurizing reagent directly. Furthermore, the mechanism of organic acid promoting limestone dissolution was suggested.

2,4-Dichlorophenol Degradation by Heterogeneous Fenton Like Reaction Using carbon-Fe Catalysts

Catalytic degradation of simulated 2,4-dichlorophenol wastewater are investigated by using self-synthesized Fe/activated carbon (AC) catalysts and hydrogen peroxide oxidation agent. Effects of the most relevant operating conditions(pH, catalysts concentration, 2,4-dichlorophenol concentration, H 2 O 2 concentration and reaction temperature) were discussed. The results indicate that the degradation rate of 2,4-dichlorophenol (400 mg/L) reach 79.9% in the presence of Fe/AC(2g/L) and hydrogen peroxide (1%) at pH = 3 after 180 minutes under normal temperature and atmospheric pressure. Kinetic studies of the catalytic reaction showed that the degradation reaction of 2,4-dichlorophenol nearly follows the first-order reaction, the reaction constant and activity energy are 0.00626 mm -1 and 66.50 kJ/mol at 30degC, respectively.

New Limestone-Gypsum Flue Gas Desulfuization Technology

A new wet FGD processes which SO2 was absorbed in the spray tower using granular limestone simultaneously adding acetic acid had been proposed. The main difference compared to conventional wet FGD process was to utilize granular limestone directly as a desulphurization reagent simultaneously adding acetic acid. Thus, the pulverizing of limestone, which causes power consumption, can be saved. Only using granular limestone¿210μm¿ directly as absorbent without acetic acid, SO2 removal efficiency and limestone utilization were too low respective 60.7% and 44%. Adding 10-30 mmol/L acetic acid, degree of desulphurization was increased to 95% and the limestone utilization was enhanced to 93.5%, comparison with fine limestone, the desulphurization efficiency and limestone utilization were respective 88% and 92.9% at the same operating conditions. Adding organic acid, buffer capacity of system was enhanced. And the influent factors such as the concentration of acetic acid, limestone slurry and SO2, residence time of flue gas were tested. The mechanism of acetic acid promoting SO2 absorption was suggested.

Hydrothermal Synthesis and Catalytic Activity of CeZrAl Oxide-Supported Pd for the Purification of Gasohol Exhaust

CeZrAl oxides (CZA) used as the support of Pd catalyst for purification of gasohol exhausts were synthesized by hydrothermal and coprecipitation method. CZA samples were characterized by N2 adsorption–desorption, XRD, H2–TPR, oxygen pulse adsorption, and XPS. The results show that the interactions between Pd and CZA with hydrothermal treatment lead to charge transfer from Pd species to Ce, which results in the presence of defect CeOx and more lattice oxygen in the catalyst. Catalytic tests demonstrate that hydrothermal treatment of CZA decreases the light-off temperature of propane, carbon monoxide, and ethanol by 50, 15, and 59°C, respectively.