Time filter

Source Type

Guo D.,Huazhong University of Science and Technology | Guo D.,SafeCleen Technologies Co. | Hu M.,Huazhong University of Science and Technology | Pu C.,Jiangxi Province Architectural Design and Research General Institute | And 6 more authors.
International Journal of Hydrogen Energy | Year: 2015

Direct reduction of iron ore pellets (DRI) with and without biomass was studied using hydrogen as The reducing agent. The influences of temperature and time on The reduction rate of pellets were investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET (Bet specific surface area) tests were adopted to interpret The mechanism of Fe2O3 reduction with H2, as well as explore The role of biomass in pellets during The reduction process. Results show that The biomass not only improve The reduction extent of The pellets, but also increase The reduction velocity index (RVI) of The pellets by 1.12%/min. The BET test indicates that The existence of biomass can create porosity in pellets by dehydration and combustion/pyrolysis, which increases The contact area between iron oxide and reducing gas during reduction process, and decreases The apparent activation energy of pellets from 122 kJ mol-1 (without biomass) to 111 kJ mol-1 (with biomass). For The DRI process, The crucial reduction step FeO → Fe is controlled by The intrinsic interfacial chemical reaction. © 2015 Hydrogen Energy Publications, LLC. Source

Abudi Z.N.,Huazhong University of Science and Technology | Abudi Z.N.,University of Baghdad | Hu Z.,Huazhong University of Science and Technology | Sun N.,Huazhong University of Science and Technology | And 5 more authors.
Energy | Year: 2016

The biochemical methane potential of co-digestion of OFMSW (organic fraction of municipal solid waste), TWAS (thickened waste activated sludge) (thermal and thermo-alkaline pretreated) and RS (rice straw) (NaOH and H2O2 pretreated) were investigated in this paper. The batch experiments were conducted at three different OFMSW/TWAS/RS (volume basis) ratios of 1:1.5:1.5, 1:0.5:0.5, and 3:0.5:0.5, respectively. In addition, to predict the biogas yield and evaluate the kinetic parameters, modified Gompertz model was introduced. A 3:0.5:0.5 ratio of OFMSW mixed with thermo-alkaline-treated TWAS and H2O2-treated RS produced the highest biogas production (558.5 L/kgVSadded) and the highest VS (volatile solids) removal efficiency (76.9%) due to the synergistic effect. The modified Gompertz model (R2: 0.868-0.998 and 0.910-0.999 for mono- and co-digestions, respectively) showed a good fit to the experimental results and the estimated parameters indicated that the pretreatments and co-digestion of substrates markedly improved the biogas production rate. © 2016 Elsevier Ltd. All rights reserved. Source

Guo D.,Huazhong University of Science and Technology | Guo D.,SafeCleen Technologies Co. | Zhu L.,University of Vaasa | Guo S.,Huazhong University of Science and Technology | And 14 more authors.
Fuel Processing Technology | Year: 2016

The syngas derived from a pyrolysis and gasification process was used as a reducing agent to produce iron ore pellets. The reduction temperature was kept between 1123 K and 1323 K, and the time was set 30 min. Results showed that the reducibility increased from 88.1% at 1123 K to 99.95% at 1323 K. The reduction rate increased with increasing reduction temperature. Further, the reaction rate in the early stage was higher than that in the later stage. The X-ray diffraction (XRD) and metallographic microscope analyses of the oxidized pellets and direct reduced iron (DRI) products showed that, the reduction process followed the reaction scheme: Fe2O3 → FeO → Fe. A kinetics analysis indicated that, the reduction rate was controlled by an interfacial chemical reaction with syngas and that the activation energy was 104.76 kJ/mol. The effect of syngas as the reducing gas on the reduction of iron ore pellets was similar to that of natural gas. The use of biomass during DRI production can eliminate CO2 emissions, energy crisis, and climate change. © 2016 Elsevier B.V. All rights reserved. Source

Hu M.,Huazhong University of Science and Technology | Hu M.,SafeCleen Technologies Co. | Guo D.,Huazhong University of Science and Technology | Guo D.,SafeCleen Technologies Co. | And 7 more authors.
Energy | Year: 2015

In order to enhance energy recovery efficiency from MSW (municipal solid waste), an in-situ steam gasification method for hydrogen production where CaO was used as CO2 sorbent and catalyst in the process was proposed. The effects of moisture content, the molar ratio of CaO to carbon in wet MSW ([Ca]/[C]) and reactor temperature on H2 yield and gas composition were investigated. The results showed that maximum hydrogen volumetric concentration (49.42 vol%) and hydrogen yield (277.67ml/g MSW) were obtained at 40wt.% moisture content at gasification temperature of 750°C and [Ca]/[C] ratio of 0.7. The proposed direct gasification of wet MSW with in situ CO2 capture process may be a promising route to produce hydrogen rich fuel gas using MSW. © 2015 Elsevier Ltd. Source

Chen Z.,Huazhong University of Science and Technology | Hu M.,Huazhong University of Science and Technology | Hu M.,SafeCleen Technologies Co. | Cui B.,CAS Wuhan Botanical Garden | And 4 more authors.
Waste Management | Year: 2016

The effects of bioleaching on sewage sludge pyrolysis were studied. Sewage sludge was treated by bioleaching with solid concentrations of 6% (w/v), 8% (w/v), 10% (w/v). Results showed that bioleaching treatment could modify the physicochemical properties of sewage sludge and enhance the metals removal. The optimum removal efficiencies of heavy metals were achieved with solid concentration of 6% (w/v) bioleaching treatment: Cu, 73.08%; Zn, 78.67%; Pb, 24.65%; Cd, 79.46%. The characterization results of thermogravimetric analysis (TGA) showed that the bioleached sewage sludge with a 6% (w/v) solid concentration treatment was the easiest to decompose. Pyrolytic experiments of bioleached sewage sludge were performed in a laboratory-scale fixed bed reactor. Results indicated that bioleaching treatment greatly influenced the product yields and gas composition. © 2015 Elsevier Ltd. Source

Discover hidden collaborations