This study shows a computation fluid dynamics simulation of Freon R11 hydrate slurry flow in a threedimensional pipeline using EulerianEulerian solidliquid multiphase model in ANSYS Fluent 14.0. A user defined function (UDF) of solid shear viscosity derived from the correlations of experimental data was written and integrated into Fluent. The numerical results of pressure gradients at different inlet velocity and different hydrate volume fractions were compared with the experimental evidences and good agreements were reached. After the model validation, the distributions of hydrate velocity magnitude and hydrate volume fraction together with the hydrate velocity vector were investigated and visibly shown through six different crosssections of the pipeline. Moreover, the effects of hydrate velocity and hydrate volume fractions on flow characteristics were explored.
This study seeks to determine the solubility of carbon dioxide in amine based deep eutectic solvents (DESs). The CO2 absorption was conducted with a solvent screening setup (SSS) and the CO2 loading was measured with a total organic carbon (TOC) analyzer. The solubility experiments were performed based on the conditions of the absorber in the postcombustion capture process (PCO2 = 15kPa and T = 40oC). Results revealed that aminebased DESs have absorption capacity that is higher than aqueous amines. The solubility of CO2 was found to increase as the molar ratio of the amine in the DES increased.
Deserts are among the most extreme environments that microalgae species thrive in, helping maintain the ecological balance of such ecosystems. Microalgae desert strains have adapted to temperature variability, salinity, nutrients scarcity, and solar radiation. These mechanisms are significant to Abu Dhabi's environment as microalgae can provide solutions to water, food, and energy security challenges. One such strain has been isolated from a small water pond in Al Wathbah desert in Abu Dhabi. This novel strain, named AAH001, was genetically characterized as a strain of Tetraselmis striata by sequencing of its Internal Transcribed Spacer (ITS) regions. Strain AAH001 exhibits growth in salinities ranging from 5ppt up to 300ppt, with the optimum growth at 75ppt. This strain exhibited salinity specific growth optima and was shown to tolerate growth temperatures of up to 40 ?C. Strain AAH001 was able to grow using air supplemented with up to 12% CO2 content.
cylindrical flowelectrode capacitive deionization(FCDI) module with continuous circulating of flowelectrodes was designed. The flowelectrodes used in this study consisted of activated carbon(AC) particles that were suspended in deionized water. It was found that the FCDI that was operated with both flowelectrodes streams were combined showed better saltremoval efficiencies than the both flowelectrodes streams were not combined. This was due to the charges were neutralized in the combined mode, ions were desorbed and the flowelectrodes were automatically regenerated when both steams were mixed. Hence, this design eliminated the energy intensive regeneration step of the conventionalCDI operational approach. The salt adsorption process by AC particles can be described by a physical adsorption process, which are affirmed by the kineticmodel. These experimental results confirmed the feasibility of using a novel cylindrical flow capacitive deionization module to remove salt ions from stream and paved the ways for scale up applications in water purification.
concentrated photovoltaic thermal (CPVT) solar collector maximizes utilization of the solar input by simultaneously generating electrical and thermal outputs. The concept of a CPVT attempts to address three main barriers to solar technologies? namely, low energy density, high cost, and low efficiencies. In the present study, two highconcentration denselypacked CPVT configurations are optically and thermodynamically designed and evaluated, incorporating exergoeconomic and environmental assessments. The designs are composed of parabolic dish concentrators, multi-junction photovoltaic cells, segmented thermoelectric generators with interconnectors, and finned minichannel heat extractors. In configuration I, the receiver assembly components are connected thermally inseries whereas in configuration II they are connected thermally inparallel. It is found that the thermally inseries configuration offers an average annual exergy efficiency of 29.12% compared to 19.28% for the thermally inparallel configuration. Both configurations offer comparable average annual energy efficiencies with a slight environmental and exergoeconomic advantage to the thermally inparallel configuration.
Catalytic coal gasification process is a useful technology used in the plants that use coal, especially the ones that use SNG (Substitute Natural Gas) and IGFC (Integrated Gasification Fuel Cell). This process was developed back in 1978 but not much work has been done on computational thermodynamic analysis of catalytic coal gasification. The purpose of this study is to model the Catalytic coal gasification process in Aspen Plus and investigate the kinetic values of the process in presence of Potassium Carbonate as Catalyst. In order to reduce CO2 emission from the coal and increase the boiler efficiency using coal as fuel, we have also included analysis of drying characteristics of coal using Aspen Plus model of the catalytic converter process. After modelling and validating the results from available experimental results, exergy analysis of the whole process is also included in the project.
The study sampled different biomass types common to arid regions that can be grown with saline water including halophytes like Salicornia bigelovii, cellulosic agricultural waste like date palms (Phoenix dactylifera), macroalgae Ulva lactuca and a microalgae Arthrospira platensis, food waste and composted waste sludge. Slow Pyrolysis was performed on all biomass types and the distribution of pyrooil, char and gases from these biomasses are presented. Pyrooil yields varied from 0.4% to 37% for different biomasses from 300 ?C to 550 ?C. Salicornia bigelovii straw gave the highest yield of pyrooil at 34% at 450?C. The calorific values of the original biomasses, the pyrooil and chars were also measured. Mass and energy balance analysis was used to compute the calorific values of the pyrolysis gases.
The CSPonD Demo prototype consists of a volumetric molten salt solar receiver that accepts concentrated solar radiation from a beamdown tower via a final optical element (FOE). This works researches the canting angles of the tower central reflectors that maximize the thermal output of the FOE. This value can vary over 20 ?pending on the selection of the canting configuration. For a given FOE construction, the best canting configuration of the central reflectors depends on the reflectivity of the FOE facets. It is found that as the reflectivity decreases, the best canting are those which bring the aiming point of the central reflector lower on the axis of the FOE.
Radiative cooling has attracted a lot of attention in the past few years due to its diverse potential applications such as in dry cooling of domestic building or even solar cells. The radiative cooling process utilizes the existence of a transparency window in Earth's atmosphere between 8 to 13 ?m. Over the past few years many designs have emerged that make use of this fact and has a selective emittance that helps dissipate the absorbed heat and lower the surface temperature. In this work we introduce a novel yet simple design that enables the cooling process. The design is composed of a single layer of Silicon Carbide (SiC) with a Distributed Bragg's Reflector (DBR) that utilizes nanoporous SiO2 films on top. FDTD simulation of the proposed structure demonstrated the two main qualities for radiative cooling, high reflection in the visible range and high ultra broadband emission within the transparency window.
Nickel tungstatetungsten oxide composite fibers were synthesized through the electrospinning method using precursor salt solutions of nickel and tungsten. Composite fiber morphology and structure were studied using SEM and Xray diffraction. The composite fibers were investigated for electrocatalytic hydrogen evolution reaction in both acidic and alkaline media where they showed good electrocatalytic activity with respect to over potentials and Tafel slopes. The study showed that the NiWO4 compound, formed during the composite fabrication, was responsible for improving the electrocatalytic performance of the fibrous catalyst. Besides electrocatalysis, nickeltungsten oxide fibers have immense potential in applications ranging from photo catalysis to gas sensing.