Search

Highlights: [•] Ni–Cu–Al catalyst for hydrogen production was synthesized by rising pH technique. [•] Experimental data were analyzed with non-stoichiometric thermodynamic calculation. [•] Catalyst deactivation due to carbon deposits in glycerol steam reforming was found. [•] Carbon removal was analyzed by TGA experiment during medium temperature oxidation. [•] Reforming was tested by separability kinetics of rate law and catalyst deactivation. [Copyright &y& Elsevier]

Abstract: The wet Flue Gas Desulfurization in the coal-fired power plants has been the most widely used because of its high SO2 removal efficiency, reliable and low utility consumption. The difficulty in the prediction of the SO2 removal from flue gas is that the performance of the system is related to a wide range of variables. In this paper, the SO2 was removed by absorbing and reacting SO2 with limestone slurry, and limestone scrubbing was accomplished in a spraying reactor. Experimental investigations for effects of different operating variables on the SO2 removal showed the reasonable process parameters such as the pH value of the liquid phase, droplet size of the spray and the flow rates of liquid and gas. The removal process was analyzed using the two-film theory of mass-transfer. Both the liquid and gas side resistances were important, and the absorption rate was controlled by a combination of both gas-film and liquid-film diffusion controls. A model of external mass-transfer with the effects of a chemical enhancement factor and sulfite concentration in the liquid phase was developed for the prediction of the SO2 removal efficiency, and the calculated values were in reasonable agreement with the experimental values. The study is considered as the one-dimensional prediction of SO2 removal and low-cost application of limestone slurry for commercial FGD technology. [Copyright &y& Elsevier]

Abstract: Five catalysts were evaluated for removal of tar components in high temperature fuel gas cleaning. 1-Methylnaphthalene was chosen as a model of the tar components. The NiMo catalyst having the highest surface area exhibited the highest activity of tar removal among the five catalysts. The effects of reaction temperature and space velocity on tar removal were studied in the range of 250–650°C and 3000–9000h−1, respectively. A lumped kinetic model was developed to describe the removal process. A sequential method to estimate the rate constants in the lumped kinetic model was adopted, which greatly simplifies the data treatments. Kinetic constants and activation energies were determined by a nonlinear regression program. The results showed that the predicted yields were very close to the experimental ones. [Copyright &y& Elsevier]

[Display omitted] • CLWS coupled with glycerol decomposition was proposed to produce H 2 and syngas. • Fe-Ce-Ni based OCs were synthesized by improved metal chelating sol–gel method. • Pure H 2 was achieved at 750℃ from CLWS by reduced OCs. • High conversion of glycerol and selectivity of syngas obtained by re-oxidized OCs. • OCs with 100:10:3 of Fe-Ce-Ni molar ratio presented high activity and stability. In this study, chemical looping water splitting (CLWS) coupled with glycerol decomposition to simultaneously produce hydrogen and syngas was proposed using the iron-cerium-nickel (Fe-Ce-Ni) based oxygen carriers (OCs). The OCs containing large amounts of iron were synthesized by the metal chelating sol–gel method and characterized by BET, XRD and TEM. During the fuel stage, the OCs of oxidation state were first reduced by the glycerol and reactive gases from catalytic decomposition of glycerol producing syngas. Afterward in the subsequent steam stage, the previously reduced OCs were re-oxidized by the steam to generate pure hydrogen, which was also named the steam iron process (SIP). The prepared Fe-Ce-Ni based OCs demonstrated the remarkable redox behavior, and exerted an important catalytic function of the partial oxidation and decomposition of glycerol at 750 ℃. The OCs with 100:10:3 of Fe-Ce-Ni molar ratio presented the best capability of oxygen transfer and the highest yields of hydrogen and syngas, reaching the water splitting hydrogen production of 11.79 mmol/g per cycle on average and guaranteeing the high conversion of glycerol and selectivity of syngas. This could be ascribed to the preferable dispersion of Ce and Ni nanoparticle on the OCs. The results also proved the effectiveness of Ce and Ni doping Fe based OCs by the improved metal chelating sol–gel method to develop the catalysts with high activity and stability for co-production of hydrogen and syngas from CLWS coupled with glycerol decomposition. [ABSTRACT FROM AUTHOR]

This paper proposes novel microencapsulated phase change material slurries (MPCSs) as both the energy storage media and heat transfer fluids. The flow and heat transfer characteristics of MPCSs have been experimentally investigated. A series of experiments were conducted in laminar, transition and turbulent flow conditions for MPCSs in a circular tube under constant heat flux, respectively. The results of pressure drop measurements showed that transportation costs of slurries were close to pure water. The heat transfer experiments demonstrated that proposed MPCSs could enhance the heat transfer performance as the heat transfer fluids for thermal system applications in comparison with pure water. The average enhancement percentages of the Nusselt number were 23.9%, 20.5% and 9.1% for MPCS of 5 wt%, and enhancement of the Nusselt number was achieved when phase change material in the microcapsules were in solid, solid/liquid and liquid states, respectively. However, heat transfer enhancement of MPCS depends on the following combination factors: the slurry concentration, the flow rate, the pumping power and the heating rate. Importantly, the phase change process must be carefully controlled in the heat transfer test section with above combination factors in order to take advantages of MPCS over pure water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electrochemical activation of biochar was achieved via limited electrooxidation. • Biochar-assisted water electrolysis reduced electricity consumption for hydrogen production. • Oxygen-containing groups enriched on biochar during its electrooxidation. • Upgraded biochar by electrochemical activation enhanced its removal of Cr(VI). • Cr(VI) removal mechanism by upgraded biochar follows attraction-reduction-complexation. Biochar-assisted water electrolysis (BAWE) has the potential to reduce the electricity consumption of hydrogen production. However, prolonged electrolysis leads to over-oxidation of biochar, reduced reactivity, and decreasing hydrogen production at cathode. Herein, we proposed the electrochemical activation of biochar via limited biochar oxidation reaction (BOR) and hydrogen evolution reaction (HER) in BAWE process, and the upgraded biochar was employed to remove Cr(VI). Distinct biochar was first pyrolyzed from three kinds of representative biomass components, cellulose, lignin, and their mixture at different temperatures. All of them exhibited excellent BOR activity, especially the biochar derived by the pyrolyzed cellulose and lignin at 800 °C (MBC-800) required a potential as low as 1.319 V vs. RHE@1 mA cm−2 using Pt electrode in 1 M KOH and achieved a Faraday efficiency almost 100% for hydrogen production. BAWE presented an energy-saving electrical consumption of 4.98 kWh Nm−3 H 2 compared to the conventional water electrolysis of 5.32 kWh Nm−3 H 2. Electrochemical oxidation enriched the oxygen-containing groups on biochar surface, which significantly improved its reductivity towards Cr(VI) and complexation with Cr(III), leading to the removal rate of Cr(VI) more than doubled. Results showed the achievement of electrochemical activation of biochar by limited electrooxidation. These findings provide a new route for the high-value utilization of biochar and energy-saving electrolytic hydrogen production. [ABSTRACT FROM AUTHOR]

• Electric vehicle driving conditions and component working modes are identified. • An assessment method for thermal management system adaptability is proposed. • Experiments verify the system performance and the evaluation method's feasibility. • An integrated thermal management system with waste heat recovery and utilization is designed. • The waste heat utilization vapor compression heat pump system improves mileage effectively. Concerns about the driving ranges of electric vehicles (EV) have led to higher requirements for vehicle thermal management systems. Efficient thermal management systems should be closely integrated with the vehicle to ensure passenger comfort and maintain adequate component operating ranges. The thermal management functions should thus accurately meet the demands of the EV and its components. Based on the driving conditions for EVs and the component thermal management requirements, this study applies different working modes for the cabin, power battery, electric motor, and electric motor controller systems under various conditions, which combines these modes into 27 feasible system working modes. Subsequently, an integrated thermal management system is designed with multi-modes adjusted by each system component to adapt environmental variations by changing the system's working mode. Also, the energy exchange between components under different modes was investigated to ensure the rationality of the designed system. The best working mode is to ensure the safety and comfort for EVs with fewer components and lower cost. It was proved to meet a wide range of adaptations to environmental changes that can be used as a method to evaluate the integrated thermal management system. The method is then applied to the target thermal management system and proves that the target system offers considerable advantages over two other benchmark thermal management systems that have been used in the mass production of electric vehicles. Finally, the cooling, heating, and defrosting performances are verified experimentally, and the vehicle mileage is calculated. The thermal management system working modes are summarized systematically. The designed thermal management system is a waste heat recovery steam compression heat pump system that can meet the functional and experimental test requirements. This study verifies that the heat management system evaluation method can evaluate the system's applicability effectively and that the waste heat utilization vapor compression heat pump system can effectively improve electric vehicle driving mileage, which manifests the potential for mass production for electric vehicle applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe2+/Fe3+ or N O 2 - / N O 3 - mediated biochar-assisted water electrolysis was studied. • Biochar oxidation reaction (BOR) was enhanced with ions mediation. • Mechanism of anodic oxidation reaction with mediator was deduced. • The activation energy of BOR was reduced by 33.9% and 58.5% with Fe2+ and N O 2 - mediation. The biochar-assisted water electrolysis (BAWE) is a promising method for clean biomass utilization and hydrogen production. But it is limited by the slow anode biochar oxidation reaction (BOR). To enhance the BOR, the mediator of Fe2+/Fe3+ or N O 2 - / N O 3 - was added to the pyrolytic biochar (PB) and tested using electrochemical methods. Both Fe2+ and N O 2 - showed stronger oxidation activity than Fe3+ and N O 3 - , and thereby presented more significant enhanced role on BOR, including the reduction in onset potential and the enlargement of current density. Fe2+/Fe3+ existence resulted in the five-step mechanism such as adsorption, redox reaction in solution, oxidation at electrode surface, and passive films formation on the biochar surface. 0.5 mol/L or less of Fe2+/Fe3+ was suggestable, while the lower acid concentration was necessary to avoid side reaction with N O 2 - existence. The Fe2+/Fe3+ acted as catalysts due to the almost unchanged total iron ions during continuous BAWE process, whereas a high consumption of N O 2 - occurred. The cathode hydrogen production was less influenced by mediator and showed comparable with the theoretical value of Faraday's law. In addition, the activation energy of BOR was significantly reduced with Fe2+ and N O 2 - mediation. The present work provides a favorable strategy for improving BOR and energy-saving production of hydrogen via BAWE process. [ABSTRACT FROM AUTHOR]