Optimizing the regeneration process parameters for forward osmosis to produce clean water at low temperature

One-fifth of the world will face sever water shortage by 2040 as climate change and a growing population pushes up demand. Recently, Qatar water resources are becoming strained and stressed as Qatar only gets seven inches of rain per year. Furthermore, World Resources Institute (WRI) ranked all the countries over the world according to the severity of water crisis and the Middle East was one of the worst regions. Nine countries were considered extremely susceptible and Qatar was ranked as a number 3, after Bahrain and Kuwait. While the country (Qatar) population is growing – as today, 2.5 million residents are forecast to multiply eightfold by 2050. Thermal processes produce more than 90% of desalinated water, where the desalination process is energy intensive, and affecting the environment. The scope of the present work is to develop a process to produce clean water at low operating conditions (temperature Please click Additional Files below to see the full abstract

Zeta Potential Optimization of Nano Chitason/SrCl2/MgO Suspension for Electrophoretic Deposition Using Taguchi Method

The stability of Electro Phoretic Deposition (EPD) suspensions containing nanoparticles relies on the impact of Zeta Potential (ZP or ). This property ensures that the nanoparticles have a consistent and stable surface charge, resulting in a uniform and stable coating. This research has been conducted as an experimental study and used the Taguchi method to design experiment optimization of the Zeta potential values, which were obtained by preparing nine suspensions. The study aimed to determine the optimal ZP value for the EPD suspension created with three materials mixed: nanochitason, Chitason/SrCl2/MgO, and a constant value of hydroxyapatite (HA) with consideration of the pH effect. After conducting an analysis, it was found that the suspension's Zeta Potential is negatively charged below a pH value of 8.22. Between 8.22 and 9.7, the ZP has a positive charge. The suspension's isoelectric point (IEP) is 8.22, with a high correlation coefficient indicating the model's reliability in predicting responses. The analysis showed that SrCl2 has the most significant impact on the suspension's ZP, followed by Chitason (CH), with MgO having the least impact. The results demonstrate the effectiveness of this analysis in determining the optimum ZP value for various solutions prepared from different biomaterial particle

Experimental and theoretical investigation of a three-phase direct contact condenser.

In the present work, for the first time, an experimental and theoretical study of the heat transfer characteristics of a bubble type three-phase direct contact condenser has been carried out. The experiments were conducted using a Perspex column of 70 cm in total height and 4 cm inner diameter, as a direct contact condenser. The active column height throughout the experiments was 48 cm. Pentane vapour at three different initial temperatures (40℃, 43.5℃ and 47.5℃), was used as the dispersed phase while tap water at a constant temperature (19℃) was used as the continuous phase. Seven different dispersed phase mass flow rates and five different continuous phase mass flow rates were tested. The experiments considered the transient temperature distribution along the direct contact condenser, the steady-state temperature distribution, the volumetric heat transfer coefficient, the heat transfer rate per unit volume and the holdup ratio. Also, the efficiency and capital cost of the direct contact condenser were estimated, and the heat transfer of the three-phase direct contact condenser during flooding was studied. Theoretical models describing the direct contact condenser were developed. These models included the transient temperature distribution, the steady-state temperature distribution and the volumetric heat transfer coefficient. These models implicitly involved new derivations for the surface heat transfer coefficient, the two-phase bubble size, the relative velocity of two-phase bubbles, the drag coefficient and the added mass of the two-phase bubble. All expressions were derived analytically except for the transient temperature distribution along the condenser which was found numerically, using MATLAB. The results showed that the mass flow rate ratio has a significant effect on the heat transfer characteristics of the condenser, while the initial temperature of the dispersed phase has only a slight effect. The models developed were fitted the experimental data well

Heat Transfer Measurement in a Three-Phase Spray Column Direct Contact Heat Exchanger for Utilisation in Energy Recovery from Low-Grade Sources

Energy recovery from low-grade energy resources requires an efficient thermal conversion system to be economically viable. The use of a liquid-liquid-vapour direct contact heat exchanger in such processes could be suitable due to their high thermal efficiency and low cost in comparison to a surface type heat exchanger. In this paper, the local volumetric heat transfer coefficient (U_v ) and the active height (H_v ) of a spray column three-phase direct contact heat exchanger (evaporator) have been investigated experimentally. The heat exchanger comprised a cylindrical Perspex tube of 100 cm height and 10 cm diameter. Liquid pentane at its saturation temperature and warm water at 45 ℃ were used as the dispersed phase and the continuous phase respectively. Three different dispersed phase flow rates (10, 15 and 20 l/h) and four different continuous phase flow rates (10, 20, 30 and 40 l/h) were used throughout the experiments. In addition, three different sparger configurations (7, 19 and 36 nozzles) with two different nozzle diameters (1 and 1.25 mm) were tested. The results showed that the local volumetric heat transfer coefficient (U_v ) along the column decreases with height. An increase in both the continuous and dispersed phase flow rates had a positive effect on U_v, while an increase in the number of nozzles in the sparger caused Uv to decrease. The active height was significantly affected by the dispersed and continuous phase flow rates, the sparger configuration and the temperature driving force in terms of the Jacob number

Heat Transfer Measurement in a Three-Phase Spray Column Direct Contact Heat Exchanger for Utilisation in Energy Recovery from Low-Grade Sources

Energy recovery from low-grade energy resources requires an efficient thermal conversion system to be economically viable. The use of a liquid-liquid-vapour direct contact heat exchanger in such processes could be suitable due to their high thermal efficiency and low cost in comparison to a surface type heat exchanger. In this paper, the local volumetric heat transfer coefficient (U_v ) and the active height (H_v ) of a spray column three-phase direct contact heat exchanger (evaporator) have been investigated experimentally. The heat exchanger comprised a cylindrical Perspex tube of 100 cm height and 10 cm diameter. Liquid pentane at its saturation temperature and warm water at 45 ℃ were used as the dispersed phase and the continuous phase respectively. Three different dispersed phase flow rates (10, 15 and 20 l/h) and four different continuous phase flow rates (10, 20, 30 and 40 l/h) were used throughout the experiments. In addition, three different sparger configurations (7, 19 and 36 nozzles) with two different nozzle diameters (1 and 1.25 mm) were tested. The results showed that the local volumetric heat transfer coefficient (U_v ) along the column decreases with height. An increase in both the continuous and dispersed phase flow rates had a positive effect on U_v, while an increase in the number of nozzles in the sparger caused Uv to decrease. The active height was significantly affected by the dispersed and continuous phase flow rates, the sparger configuration and the temperature driving force in terms of the Jacob number

Yield Optimization for The Extraction of Organic Compounds from Okra Leaves Wastes

An important area of research is the extraction of organic chemicals from plants and herbs. Considering the fact that the extracts have numerous commercial and pharmacological uses. Furthermore, limiting the optimal working region is made easier by employing an appropriate experimental design. Solvent extraction is the technique most frequently used to separate organic components from plants. However, the conditions of extracting solvent that is utilized greatly affects the yields of the extract and, as a result, the organic activities of the plant parts. This research deals with the extraction of solid organic compounds from the okra leaves using water as a solvent. A Soxhlet apparatus was used for the extraction process. The influence of extraction time, solvent volume, and okra powder mass on the yield percentage was optimized. Two mathematical models were suggested: second-order polynomials and power models. A higher correlation coefficient was obtained with the polynomial model. The maximum extraction yield was obtained at optimum values of 200.3 min, 29.07 g, and 290.7 ml for time, okra powder mass, and solvent volume, respectively. It is evident from mathematical formulas that the impact of time was less significant than the effects of solvent volume and powder mass. On the other hand, the power model and the second-order quadratic interaction model had correlation coefficients of 0.4849 and 0.9707, respectively

Convective Heat Transfer Measurements in a Vapour-Liquid-Liquid Three-Phase Direct Contact Heat Exchanger

Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40℃,43.5℃ and 47.5℃) was directly contacted with water (the continuous phase) at 19℃. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases

Measuring the average volumetric heat transfer coefficient of a liquid–liquid–vapour direct contact heat exchanger

The average volumetric heat transfer coefficient in a spray column liquid–liquid–vapour direct contact evaporator has been experimentally investigated. The experiments were carried out utilising a cylindrical Perspex tube of diameter 10 cm and height and 150 cm. Saturated liquid n-pentane and warm water at 45 °C were used as the dispersed and continuous phases, respectively. Three different dispersed flow rates (10, 15 and 20 L/h) and four different continuous phase flow rates (10, 20, 30 and 40 L/h) were used in the study. The effect of different parameters, such as the initial drop size, continuous and dispersed phase flow rates and sparger configuration, on the average volumetric heat transfer coefficient in the evaporator was studied. The results showed that the average volumetric heat transfer coefficient was reduced as the initial drop size increased. Also, both the continuous phase and the dispersed phase flow rates have a significant positive impact on the average volumetric heat transfer coefficient