Papers by Abdulrahim Alzahrani
RSC Advances, 2016
Experimental data on hydrogen production via a partial oxidation of methanol (POM) reaction on Au... more Experimental data on hydrogen production via a partial oxidation of methanol (POM) reaction on Au/ZrO₂, Au/CeO₂–ZrO₂ and Au/CeO₂–ZrO₂–TiO₂ catalysts is presented in this article. The gold catalysts were prepared by a deposition–precipitation (DP) method and characterized by XRF, XRD, H₂-TPR, XPS methods N₂ adsorption. The activity results show that the catalyst containing 1 wt% gold supported on a CeO₂–ZrO₂ carrier demonstrates very good hydrogen selectivity and the highest catalytic activity among all tested catalysts. The optimal working temperature established was 375 °C. At this temperature 75.5% hydrogen selectivity was registered. The presence of oxidized gold in the catalyst's composition as well as the support redox properties are the major factors controlling the observed catalytic activity.
ABSTRACT The potential of utilizing an ANN modeling approach to simulate and predict the hydrogen... more ABSTRACT The potential of utilizing an ANN modeling approach to simulate and predict the hydrogen production of Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564) was investigated. Sixty experimental data records have been utilized to develop the ANN model. In this paper, a unique architecture has been introduced to mimic the inter-relationship between three input parameters: initial substrate concentration, initial medium pH and temperature (10 g/l, 6.0±0.2, 37°C, respectively). A comparative analysis with a traditional Box-Wilson Design (BWD) statistical model proved that the ANN model output significantly outperformed the BWD model at similar experimental conditions. The results showed that the ANN model provides a higher level of accuracy for the H2 prediction and fewer errors and that it overcomes the limitation of the BWD approach with respect to the number of records, which merely considers a limited length of stochastic patterns for H2 prediction.
Journal of Health Politics, Policy and Law, 1992
with a concentration in Socio-environmental Performance in Production Processes, which she finish... more with a concentration in Socio-environmental Performance in Production Processes, which she finished in May 2012. The dissertation produced the paper: Correlation of denitrifying catabolic genes with N2O and N2 emissions during swine slurry composting,
International Journal of Hydrogen Energy, 2018
This work focuses on a novel synthesis route, using citric acid as a chelating agent, for the for... more This work focuses on a novel synthesis route, using citric acid as a chelating agent, for the formation of g-Mo 2 N and Co 3 Mo 3 N bulk catalyst and their application for NH 3 decomposition reaction for hydrogen production having its application for onboard generation of hydrogen for fuel cell in transportation vehicles. Successful formation of the pure bulk phase of Co 3 Mo 3 N was confirmed by using XRD, XPS, HRTEM techniques. The prepared Co 3 Mo 3 N catalyst showed high surface area 15.23 m 2 /g and high catalytic activity compared to bulk g-Mo 2 N for this decomposition reaction, having 97% conversion of NH 3 at 550 C at 6000 h À1 .
RSC Adv., 2016
Gold nanoparticles supported on CeO2–ZrO2 give 75.5% H2 selectivity at 375 °C for a partial oxida... more Gold nanoparticles supported on CeO2–ZrO2 give 75.5% H2 selectivity at 375 °C for a partial oxidation of methanol reaction.
Korean Journal of Chemical Engineering, 2015
Power and desalination plants are one of the main anthropogenic sources for CO 2 generation, whic... more Power and desalination plants are one of the main anthropogenic sources for CO 2 generation, which is one of the key elements to cause greenhouse gas effect and thus contribute to the global warming. Fly ash (FA) generated in desalination and power plants was converted into activated carbon (AC) treated with KOH at higher temperature and tested for CO 2 capturing efficiency. Morphological characteristics of FA such as BET specific surface area (SSA), pore volume, pore diameter, and pore size distribution (PSD) were performed using N 2 adsorption isotherm. CO 2 adsorption capacity and adsorption isotherms of CO 2 over AC were measured by performing thermogravimetric analysis at different temperatures. BET SSA of 161 m 2 g −1 and adsorption capacity of 26 mg CO 2 /g AC can be obtained by activation at KOH/FA ratio of 5 at 700 o C and activation time of 2 h. Therefore, great potential exists for producing AC from FA, which will have the positive effect of reducing the landfill problem and global warming.
☯ These authors contributed equally to this work.
International Journal of Engineering and Technology, Apr 30, 2018
The humidification-dehumidification process (HDH) is a thermal technique adapted for water desali... more The humidification-dehumidification process (HDH) is a thermal technique adapted for water desalination. This technique has many advantages such as moderate installation, simplicity and operates at relatively low temperatures when compared with other commercial thermal processes. HDH process is perfectly suitable for the decentralized areas where a small-scale desalination technology uses renewable resources of energy. The aim of this paper is to present the experimental analysis of the process providing the principle of functioning and the characteristics of the process when a different key variable such as air flow rate and humidifier inlet water temperature is altered. The experiment designed, installed and operated where air flow rates tested at constant humidifier inlet water temperature. To study the influence of air flow rate variation on the system, several experimental runs are implemented at different air flow rates at constant inlet water temperature. The experiments are repeated where humidifier inlet water temperature is changed. The system evaluated after steady state operation within one hour, and the production is collected. Finally, the system analyzed to find the effect of air/water flow ratio on the system productivity, humidifier mass transfer coefficient and dehumidifier overall heat transfer coefficient. Moreover, the sensible heat from the humidifier inlet water is studied as the analysis includes the inlet water temperature effect on the process. The system best results obtained at the maximum tested air flow rate where the GOR was 0.22 and the production cost of 0.043 US$/liter.The highest productivity of the system found to be 5.424 l/hr at 50 o C humidifier inlet water temperature. The general outcome of the study provides that HDH desalination process is more favorable towards increasing the air flow rates and humidifier inlet water temperature where the mass transfer and overall heat transfer coefficients also increased. The system optimized for best economic and operating conditions. Keyword-Desalination, Humidification, Dehumidification, Design. I. INTRODUCTION Large parts of Saudi Arabia are water-stressed. Large-scale desalination technologies have become widely available as commercial technology over the last few decades. On the other hand, small-scale desalination technologies for arid areas have not attracted similar commercial interests. The major challenges for a remote water production are the need for systems that incur simplicity, inexpensive components,the ability to adapt to renewables, and ensure relatively maintenance-free operation. Also it is recommended to study simplest efficient designs in order to be used for arid areas. El-Halwagi [1] provided the shortcut method for the design of once-through multi-stage flash (MSF) in order to obtain better design analysis of the unit components and process integration which reveals favorable results compared with the existing plant data. Desalination processes such as Multi-effect distillation (MED), reverse osmosis (RO) are optimized for better operation, design and best economic output [2]-[4] to satisfy the fresh water demand.Among the many available technologies, humidification-dehumidification (HDH) desalination technology is the promising and decentralized drinking water technology. The process includes simple and separate components for each of the thermal processes; this allows each component to be independently designed, which require less capital cost. It can operate over a wide range of raw water quality without the need for complex maintenance and operations. One of the features of the HDH concept is the ability to operate at low temperature that makes it one of the best solar energy applications. In order to improve the water productivity of HDH experimental analysis of the process is needed. The process also known to be sensitive to many variable which affect the productivity such as air flow, feed water flow, feed water temperature, and the configuration of the major components. The productivity of the system has shown a certain improvement with increasing the water temperature and air flow [5], although this increase has optimum value for each parameter [6]. When the energy performance of the process concerned, the mass of water produced per unit heat can be analyzed by obtaining the gained output ratio (GOR) [7]-[9]. Both unit productivity and GOR are affected positively by increasing the feed water temperature [10]. The investigation of pulsed water flow and its effect on the performance of the (HDH) process
Asia-Pacific Journal of Chemical Engineering
Processes
Solar energy is becoming a promising source of heat and power for electrical generation and desal... more Solar energy is becoming a promising source of heat and power for electrical generation and desalination plants. In this work, an integrated study of modeling, optimization, and experimental work is undertaken for a parabolic trough concentrator combined with a humidification and dehumidification desalination unit. The objective is to study the design performance and economic feasibility of a solar-driven desalination system. The design involves the circulation of a closed loop of synthetic blend motor oil in the concentrators and the desalination unit heat input section. The air circulation in the humidification and dehumidification unit operates in a closed loop, where the circulating water runs during the daytime and requires only makeup feed water to maintain the humidifier water level. Energy losses are reduced by minimizing the waste of treated streams. The process is environmentally friendly, since no significant chemical treatment is required. Design, construction, and opera...
DESALINATION AND WATER TREATMENT
International Journal of Engineering and Technology, 2016
Design, simulation, and manufacturing process of an integrated thermal photovoltaic closed parabo... more Design, simulation, and manufacturing process of an integrated thermal photovoltaic closed parabolic collector (ITPVCPC) using composite material is presented in this paper. The design includes two flanges for supporting photovoltaic panels. Two cases of troughs were designed and studied, one with glass cover over the aperture area and another without it in order to investigate the structure rigidity and solar ray collection in the absorber tube. Three-dimensional modelling and structural finite element analysis (FEA) based simulation was done for the design. In the simulation, the ITPVCPC structure was subjected to the upper limits of wind pressure and temperature-rise loadings similar to the real working conditions. Optical analysis was done for the trough to study the effect of structure deformation on solar ray collection. The glass covered ITPVCPC showed higher structure deformation than the one without glass. Glass fiber with polyester resin was used in the manufacture of ITPVCPC for its low price compared to other composite materials. The study shows that glass fiber (with polyester matrix) is an ideal composite material for ITPVCPC for its high rigidity, low cost, and ease of manufacture. This design is successfully implemented and is the source of thermal and electrical power for a solar desalination system installed in Jeddah, Saudi Arabia. Keywords: Finite element analysis (FEA), concentrating solar power (CSP), hand-layup method, glass fiber reinforced polymer (GFRP) I.
Biosorption of cadmium and lead from aqueous solution was investigated using green algae Chlorell... more Biosorption of cadmium and lead from aqueous solution was investigated using green algae Chlorella vulgaris at room temperature and at pH adjusted to 7.0. Various sorption parameters such as contact time, initial metal ion concentration and biomass quantity were studied. The equilibrium experimental data are well represented by Langmuir model among two-parameter models. It was noted that the maximum adsorption capacity for cadmium and lead was 149.9 and 178.5 mg (metal) g −1 biomass, respectively. The kinetic data were fitted by models including pseudofirst order and pseudo-second order. It was observed that, the pseudo-first-order kinetic model describes the biosorption of cadmium and lead ions onto C. vulgaris biomass.
Proceeding of the Bulgarian Academy of Sciences, 2013
Cobalt supported on carbon nanotubes catalyst is much more active in reaction of ammonia decompos... more Cobalt supported on carbon nanotubes catalyst is much more active in reaction of ammonia decomposition than nickel and iron catalysts. The observed low temperature activity of Co/carbon nanotubes catalysts is promising option for creating of ammonia decomposition catalysts with low working temperatures.
Petroleum-based products are the major sources of energy for industry and daily life. The world p... more Petroleum-based products are the major sources of energy for industry and daily life. The world production of crude oil is more than three billion tons per year, and about the half of this is transported by sea. Oil spill accidents result in significant contamination of the ocean and shoreline environment. Annually, more than one million tons of petroleum are estimated to end up in the sea.
Comptes Rendus De L Academie Bulgare Des Sciences Sciences Mathematiques Et Naturelles, May 1, 2014
Four multi-wall carbon nanotubes with different functional groups, SWC-NTs and graphene were used... more Four multi-wall carbon nanotubes with different functional groups, SWC-NTs and graphene were used as nickel catalyst support. The supported nickel catalysts were characterised by XPS, XRD and TPR techniques. The characterisation techniques showed that carbon nanotube surface functional groups have no significant influence on the size of nickel species and phase composition. Nickel reducibility was slightly affected by the carbon nanotubes with different functional groups. Ammonia decomposition reaction tests have shown that catalysts supported on carbon nanotubes with different functional groups have close activity per gram catalyst, however if we take into account the weight content of different functional groups in the used carrier the -NH 2 group is leading to the preparation of most active catalysts.
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Papers by Abdulrahim Alzahrani