Theoretical modelhas been applied to predict the performance of Direct Contact Membrane Distillat... more Theoretical modelhas been applied to predict the performance of Direct Contact Membrane Distillation (DCMD) based on the analysis of heat and mass transfer through the membrane. The performance of DCMD on the account of different operating parameters had been predicted. Feed inlet temperature, coolant inlet temperature, feed flow rate and coolant flow rate are the considered performance variables. Based on the data obtained from theoretical model, statistical analysis of variance (ANOVA) was then performed to determine the significant effect of each operating factors on the DCMD system performance. A new regression model was subsequently developed for predicting the performance of the DCMD system. Resultsrevealed that both theoretical and regression models were in good agreement with each other and also with the selected experimental data used for validation. The maximum percentage error between the two models was found to be1.098%. Hence, the developed regression model is adequate ...
This paper presents the performance of a water heated, cross flow humidification dehumidification... more This paper presents the performance of a water heated, cross flow humidification dehumidification (HDH) desalination system with brine recirculation designed, constructed and operated in a controlled environment.The presented HDH units are easy to build, do not require sophisticated maintenance and are suitable for remote areas where high level of technical background is not abundant.The influence of mass ratio (MR) at different hot water temperature on Gain output ratio (GOR), Recovery ratio (RR), humidifier, and dehumidifier effectiveness is investigated. The system is operated at different hot water temperatures, hot water flow rate ranging from 60 – 75 o C, and 4 – 18 L/min, respectively. The obtained results show that the built system is capable of producing distillate water of about 92 Liters per day,a GOR of 1.3, and the components effectiveness ranges from 92 – 97% and 53 – 79% for dehumidifier and humidifier respectively.
A hybrid Multi-Stage Flash–Humidification Dehumidification (MSF-HDH) desalination system is inves... more A hybrid Multi-Stage Flash–Humidification Dehumidification (MSF-HDH) desalination system is investigated for energy recovery from an MSF system. The hybrid MSF-HDH system increases total productivity and performance ratio and reduces brine rejection. Hot condensed steam that leaves the MSF brine heater is used to warm the rejected pretreated brine from MSF to a higher temperature suitable for HDH system operation (about 60 °C). This allows us to increase the product (desalinated water) without additional “external” energy input to the hybrid system. Four different layouts of the integrated MSF-HDH system are presented and compared. The results show that an HDH system can utilize over 66% of an existing MSF brine blowdown, while the hybrid system can achieve a gained output ratio—GOR, water recovery ratio—RR, productivity and freshwater cost of 8.73, 44.86%, 30,549 m3/day and 1.068 $/m3 of freshwater, respectively. Utilizing 66.96% of MSF brine blowdown by the HDH system leads to a d...
This study focuses on energy and entropy analysis to theoretically investigate the performance of... more This study focuses on energy and entropy analysis to theoretically investigate the performance of a pilot scale dual heated humidification-dehumidification (HDH) desalination system. Two cases of HDH systems are considered in the analysis. The first case is a dual heated (DH) cycle consisting of 1.59 kW air heater and 1.42 kW water heater with a heat rate ratio of 0.89 (CAOW-DH-I). Whereas the second case is a dual heated HDH cycle comprising of 1.59 kW air heater and 2.82 kW water heater with a heat rate ratio of 1.77 (CAOW-DH-II). As a first step, mathematical code was developed based on heat and mass transfer and entropy generation within the major components of the system. The code was validated against the experimental data obtained from a pilot scale HDH system and was found to be in a good agreement with the experimental results. Theoretical results revealed that there is an optimal mass flowrate ratio at which GOR is maximized, and entropy generation is minimized. Furthermor...
Removal of heavy metal ions from wastewater is of prime importance for a clean environment and hu... more Removal of heavy metal ions from wastewater is of prime importance for a clean environment and human health. Different reported methods were devoted to heavy metal ions removal from various wastewater sources. These methods could be classified into adsorption-, membrane-, chemical-, electric-, and photocatalytic-based treatments. This paper comprehensively and critically reviews and discusses these methods in terms of used agents/adsorbents, removal efficiency, operating conditions, and the pros and cons of each method. Besides, the key findings of the previous studies reported in the literature are summarized. Generally, it is noticed that most of the recent studies have focused on adsorption techniques. The major obstacles of the adsorption methods are the ability to remove different ion types concurrently, high retention time, and cycling stability of adsorbents. Even though the chemical and membrane methods are practical, the large-volume sludge formation and post-treatment requ...
ABSTRACT This study investigates the performance of a novel humidification dehumidification (HDH)... more ABSTRACT This study investigates the performance of a novel humidification dehumidification (HDH) desalination system integrated into a vapor compression (VC) heat pump. The integrated heat pump delivers the necessary heating and cooling loads to the HDH desalination unit. Three different layouts (system A, system B, and system C) of water desalination plants are proposed and evaluated analytically at different operating conditions, such as water temperature, water flowrate, mass flowrate ratio (MR), and humidifier effectiveness. The investigated performance metrics of the proposed HDH desalination system are the gained output ratio (GOR), freshwater production rate, specific electrical energy consumption (SEEC), recovery ratio (RR) and cost of freshwater production. System A is without heat recovery, system B has heat recovery through preheating feed inlet saline water, while system C has heat recovery through preheating inlet air to the humidifier. The parametric analysis indicates that GOR, water productivity, and RR improve with increasing water temperature and humidifier effectiveness, while the specific electrical energy consumption decreases at the same conditions. The findings show the existence of an optimum mass flowrate ratio (MR) at which system performances are maximized. Results also reveal that the systems with the option of energy recovery provide the highest gained output ratio, recovery ratio and productivity, and the least specific electrical energy consumption. Additionally, depending on various system and cost parameters, the price of freshwater production from the proposed systems varies from 34.27 $/m3 to as low as 7.33 $/m3 of freshwater.
Theoretical modelhas been applied to predict the performance of Direct Contact Membrane Distillat... more Theoretical modelhas been applied to predict the performance of Direct Contact Membrane Distillation (DCMD) based on the analysis of heat and mass transfer through the membrane. The performance of DCMD on the account of different operating parameters had been predicted. Feed inlet temperature, coolant inlet temperature, feed flow rate and coolant flow rate are the considered performance variables. Based on the data obtained from theoretical model, statistical analysis of variance (ANOVA) was then performed to determine the significant effect of each operating factors on the DCMD system performance. A new regression model was subsequently developed for predicting the performance of the DCMD system. Resultsrevealed that both theoretical and regression models were in good agreement with each other and also with the selected experimental data used for validation. The maximum percentage error between the two models was found to be1.098%. Hence, the developed regression model is adequate ...
This paper presents the performance of a water heated, cross flow humidification dehumidification... more This paper presents the performance of a water heated, cross flow humidification dehumidification (HDH) desalination system with brine recirculation designed, constructed and operated in a controlled environment.The presented HDH units are easy to build, do not require sophisticated maintenance and are suitable for remote areas where high level of technical background is not abundant.The influence of mass ratio (MR) at different hot water temperature on Gain output ratio (GOR), Recovery ratio (RR), humidifier, and dehumidifier effectiveness is investigated. The system is operated at different hot water temperatures, hot water flow rate ranging from 60 – 75 o C, and 4 – 18 L/min, respectively. The obtained results show that the built system is capable of producing distillate water of about 92 Liters per day,a GOR of 1.3, and the components effectiveness ranges from 92 – 97% and 53 – 79% for dehumidifier and humidifier respectively.
A hybrid Multi-Stage Flash–Humidification Dehumidification (MSF-HDH) desalination system is inves... more A hybrid Multi-Stage Flash–Humidification Dehumidification (MSF-HDH) desalination system is investigated for energy recovery from an MSF system. The hybrid MSF-HDH system increases total productivity and performance ratio and reduces brine rejection. Hot condensed steam that leaves the MSF brine heater is used to warm the rejected pretreated brine from MSF to a higher temperature suitable for HDH system operation (about 60 °C). This allows us to increase the product (desalinated water) without additional “external” energy input to the hybrid system. Four different layouts of the integrated MSF-HDH system are presented and compared. The results show that an HDH system can utilize over 66% of an existing MSF brine blowdown, while the hybrid system can achieve a gained output ratio—GOR, water recovery ratio—RR, productivity and freshwater cost of 8.73, 44.86%, 30,549 m3/day and 1.068 $/m3 of freshwater, respectively. Utilizing 66.96% of MSF brine blowdown by the HDH system leads to a d...
This study focuses on energy and entropy analysis to theoretically investigate the performance of... more This study focuses on energy and entropy analysis to theoretically investigate the performance of a pilot scale dual heated humidification-dehumidification (HDH) desalination system. Two cases of HDH systems are considered in the analysis. The first case is a dual heated (DH) cycle consisting of 1.59 kW air heater and 1.42 kW water heater with a heat rate ratio of 0.89 (CAOW-DH-I). Whereas the second case is a dual heated HDH cycle comprising of 1.59 kW air heater and 2.82 kW water heater with a heat rate ratio of 1.77 (CAOW-DH-II). As a first step, mathematical code was developed based on heat and mass transfer and entropy generation within the major components of the system. The code was validated against the experimental data obtained from a pilot scale HDH system and was found to be in a good agreement with the experimental results. Theoretical results revealed that there is an optimal mass flowrate ratio at which GOR is maximized, and entropy generation is minimized. Furthermor...
Removal of heavy metal ions from wastewater is of prime importance for a clean environment and hu... more Removal of heavy metal ions from wastewater is of prime importance for a clean environment and human health. Different reported methods were devoted to heavy metal ions removal from various wastewater sources. These methods could be classified into adsorption-, membrane-, chemical-, electric-, and photocatalytic-based treatments. This paper comprehensively and critically reviews and discusses these methods in terms of used agents/adsorbents, removal efficiency, operating conditions, and the pros and cons of each method. Besides, the key findings of the previous studies reported in the literature are summarized. Generally, it is noticed that most of the recent studies have focused on adsorption techniques. The major obstacles of the adsorption methods are the ability to remove different ion types concurrently, high retention time, and cycling stability of adsorbents. Even though the chemical and membrane methods are practical, the large-volume sludge formation and post-treatment requ...
ABSTRACT This study investigates the performance of a novel humidification dehumidification (HDH)... more ABSTRACT This study investigates the performance of a novel humidification dehumidification (HDH) desalination system integrated into a vapor compression (VC) heat pump. The integrated heat pump delivers the necessary heating and cooling loads to the HDH desalination unit. Three different layouts (system A, system B, and system C) of water desalination plants are proposed and evaluated analytically at different operating conditions, such as water temperature, water flowrate, mass flowrate ratio (MR), and humidifier effectiveness. The investigated performance metrics of the proposed HDH desalination system are the gained output ratio (GOR), freshwater production rate, specific electrical energy consumption (SEEC), recovery ratio (RR) and cost of freshwater production. System A is without heat recovery, system B has heat recovery through preheating feed inlet saline water, while system C has heat recovery through preheating inlet air to the humidifier. The parametric analysis indicates that GOR, water productivity, and RR improve with increasing water temperature and humidifier effectiveness, while the specific electrical energy consumption decreases at the same conditions. The findings show the existence of an optimum mass flowrate ratio (MR) at which system performances are maximized. Results also reveal that the systems with the option of energy recovery provide the highest gained output ratio, recovery ratio and productivity, and the least specific electrical energy consumption. Additionally, depending on various system and cost parameters, the price of freshwater production from the proposed systems varies from 34.27 $/m3 to as low as 7.33 $/m3 of freshwater.
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Papers by Dahiru Lawal