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A novel nano phase change material emulsion (NPCE) with low supercooling and high thermal conductivity was prepared by sonication method. N-octadecane was employed as phase change material, multi-walled carbon nanotubes (MWCNTs) were utilised as high thermal conductivity material, and octadecanol was utilised as nucleating agent. The characterization and thermal properties of the nanoemulsions prepared with various concentrations of MWCNTs and octadecanol were measured and analysed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), particle size analyser, differential scanning calorimeter (DSC) and thermal conductivity meter. The results indicated that the nanoemulsions prepared had great stability, low supercooling and enhanced thermal conductivity. The thermal conductivity was enhanced by 4.32% for 10 wt% nanoemulsion with addition of 1 wt% MWCNTs. The supercooling degree of 20 wt% nanoemulsion was decreased by 36.4% from 17.3 °C to 11.0 °C with addition of 1 wt% octadecanol. It can be concluded that the nanoemulsions prepared were able to be utilised as heat transfer and energy storage fluids, with great potential in thermal system applications.

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.

In this study, the effects of sorbent addition for in-situ CO2 removal on hydrogen production by sorption-enhanced chemical looping steam reforming (SE-CLSR) of ethanol have been evaluated in an alternating fixed-bed reactor using a mixture of NiO/Al2O3 oxygen carrier catalyst (OC) and CaO based sorbent at moderate operating conditions (T: 600 °C, P: 1.0 atm and S:C: 3.0). The experimental data were compared with chemical equilibrium analysis based on the minimization of Gibbs free energy. The results demonstrated that NiO component in the OC was first reduced by ethanol and the reduced OC was responsible of catalytic steam reforming and water gas shift (WGS) for hydrogen production. The CO2 produced was efficiently removed by CaO based sorbent, also resulting in the process intensification considerably. It appears that the superior molar ratio of sorbent to OC (Ca/Ni) is to be 2.0–3.0 and the highest hydrogen selectivity and feeding conversion were obtained at 3.0 of Ca/Ni ratio. Hydrogen production was inhibited using further high Ca/Ni ratio due to the OC particles were surrounded and diluted by sorbent. The exothermic reactions also provided the heat to raise the temperature of the reactor. In-situ CO2 removal by solid sorbent promotes ethanol dehydration and C C carbon bonds cleavage, and thus, the hydrogen production route of conventional CLSR is changed. Continuous high-purity hydrogen production was achieved by integrating the oxidization, steam reforming, WGS, and in situ CO2 capture in an alternating fixed-bed reactor.

Hydrogen production and reduction of Ni-based oxygen carriers (OCs) during chemical looping steam reforming (CLSR) of ethanol were studied in a fixed-bed reactor using four OCs with different supports including NiO/SBA-15, NiO/MCM-41, NiO/MMT and NiO/Al2O3. The OCs prepared were characterized by N2 adsorption-desorption, TPR, TPO, XRD, TEM, FTIR and TGA-DSC. The results demonstrated that NiO component in all the OCs was first reduced by ethanol and the reduced OCs were responsible of catalytic steam reforming and water gas shift for hydrogen production. Mesoporous NiO/SBA-15 presented increasing conversion of NiO reduction and the highest selectivity of hydrogen production. The conversion of ethanol increased with reactions proceeding until the highest value is reached after about ∼300s, and the negative steam conversion obtained was resulted from H2O formation from ethanol oxidation by OCs. Compared with MMT and Al2O3 supports, the oxidization of NiO with MCM-41 and SBA-15 supports was very fast and less carbon was formed and deposited. Enhancement in hydrogen production from CLSR process was achieved by in-situ CO2 removal. Shrinking Core model (SCM) based on the constant pattern model for fixed-bed reactor indicated the rates of OCs reduction with ethanol were mainly controlled by surface chemical reaction and product layer diffusion. The reduction process was found to undergo three different rate-limiting stages, and the critical times for changes in the rate-limiting steps were determined.

The electrochemical Bunsen reaction has been proposed as an innovative and promising method compared with the traditional Bunsen reaction for the sulfur–iodine cycle, and its kinetics were studied in this work. Polarization curves were measured using platinum electrode in the different concentrations of SO2–H2SO4–H2O and I2–HI–H2O solutions at a temperature range of 303–353 K. Fundamental kinetic parameters, namely exchange current density, Tafel slope, asymmetry factor, were determined for anodic SO2 oxidation reaction and cathodic I2 reduction reaction according to the Tafel plots. The activation energy and pre-exponential factor for the electrode reactions were also analyzed using Arrhenius relation. Results indicated that an increase in the SO2 concentration in the anolyte and the I2 concentration in the catholyte reduced the activation energy, contributing to the easier anode and cathode reaction. Take high electrode reaction rate and easier electrode reactions into account, the initial SO2 concentration of 1.509 mol/L and the I2/HI molar ratio of 0.5 could be optimal.

In this paper, pore network simulations are carried out to explore the effects of micro porous layer (MPL) and its crack location on the liquid and oxygen transport in the gas diffusion material (GDM) of proton exchange membrane fuel cell (PEMFC). The constructed network is composed of cubic pores connected by throats of square cross section. The GDM is partially screened by the land, and the MPL is assumed to have a crack. When the MPL crack is considered under the land in the model, the predicted results agree with experimental findings regarding the effect of MPL on the liquid saturation and distribution in the GDM. This indicates that the liquid may prefer to flow through the MPL crack under the land. The role of MPL in the fuel cell performance is revealed to be dependent on the oxygen effective diffusivity of MPL and GDL. Therefore, caution should be taken before employing the MPL to improve the cell performance. Based on the present studies, some guidelines are gained for the GDM design and optimization.

Combing with comparability principle, and on the premise of satisfying the same flow state, using the method of modelling blew, simulating the steam of turbine with flow air. This paper puts forward a kind of micro modelling equipment of condenser-throat and gives the design project of the micro modelling experiment, and the feasibility analysis to the micro modelling equipment is studied. Influence proportion of different equipments was compared in flow resistance and flow state respectively. On this basis, analysis of the influence of body and inner-equipment on the flow resistance, which mainly includes the disturbance by the body, sticking effect of the body, the flow resistance by the low-pressure heater and so on, and gets the curve of steam flow resistance with the dimension of body structure and inner-equipment.