Coupling between extraction, reaction, and liquid-liquid contact hydrodynamics have quantitative as well as qualitative implications on the performance of un-agitated perforated plate extractive ...reactors. Models, which take into account the effect of flow dynamics on mass transfer performance, are developed to analyze the steady state behavior of such columns when conducting a chemical reaction in the continuous extract phase. New expressions are derived for the composition profiles in the cases of physical extraction, slow, and infinitely fast reactions. Typical results show that the raffinate purity may either increase or decrease on increasing the solvent rate depending on the interaction between column fluid dynamics, mass transfer, and reaction kinetics.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Coupling of a pervaporation membrane unit with an esterification reactor has been undertaken with a view to improve the overall efficiency of the esterification process through removal of one of the ...products. The esterification reaction of acetic acid with methanol in the presence of two alternative heterogeneous catalysts Nafion resin (NR) and silica sulfuric acid (SSA) is investigated on the laboratory scale. The system consists of a batch reactor externally coupled with pervaparation (PV) module containing a Nafion membrane. The effect of different parameters on the esterification / pervaporation system is explored. The studied parameters include reactants molar ratio, temperature, and catalyst weight percent. The results show that the water diffusion through the PV membrane helps to break the thermodynamic equilibrium barrier of reversible esterification reaction and improve the reaction conversion. The maximum conversion reached 96.76 % after 60 min at 60 ºC, 3% silica sulfuric acid as catalyst, with a reactant to acid molar ratio of 8:1, and a membrane surface area to reactor volume of 1.3 cm-1. .
Despite the considerable amount of data generated with respect to biochar application in the anaerobic digestion of sewage sludge, there is a research gap for correlations linking biochar ...physico-chemical parameters to anaerobic digestion performance. In the current study, cumulative methane production (CMP) from anaerobic digestion of sewage sludge amended with biochar is modeled by an Artificial Neural Network (ANN) (2 hidden layers, 12 neurons each) based on data compiled from 51 published biomethane potential tests (BMP). The model reflects the effects of 13 operational parameters covering physico-chemical properties of biochar, sludge characterization and operating conditions. Various types of sewage sludge and biochar under both mesophilic and thermophilic conditions have been successfully modeled with an R2 of 0.9924. An importance analysis is conducted to evaluate the significance of the model input parameters to CMP. Results indicate that operating conditions are more significant to CMP and that CMP is strongly correlated with biochar physical properties and chemical composition where chemical composition has the dominant effect. Overall, this study proves that biochar physico-chemical parameters are correlated to CMP and enables its forecasting under unexamined conditions thus assisting in process optimization, scale up and techno-economic analyses without resorting to BMP tests.
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•An ANN model for anaerobic digestion of sludge amended with biochar is developed.•Methane yield is predicted for various biochars and operating conditions.•Thirteen independent process parameters are considered for the first time.•Biochar physico-chemical properties are strongly correlated to methane yield.•Dominant effect of biochar chemical composition on cumulative methane production.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This article assesses the air pollution data from two monitoring stations in Kuwait. The measurements cover major pollutants, i.e., CO, CO
2
, methanated and non-methanated hydrocarbons, NO
x
, SO
2
..., O
3
, and particulate matter (PM10). The data also includes meteorological parameters, i.e., solar intensity, temperature, wind speed, and wind direction, and has been collected over a period 4 years, from 2001 to 2004. Data analysis includes the assessment of annual hourly averages and 1-h maxima. Typical pollutant concentration trends, similar to those previously reported for Kuwait and for other locations around the world, are observed except for particulate matter measurements, which have higher values because of proximity to the desert. Emissions of nitrogen oxides show a consistent increase over the years. This is caused by the increase in the number of motor vehicles and the expansion in power generation and industrial activities. The data collected is a subset of the air quality criteria, as defined by the US EPA (United States Environmental Protection Agency).
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Purpose - The objective of this study is to develop and validate a neural-based modelling methodology applicable to site-specific short- and medium-term ozone concentration forecasting. A novel ...modelling technique utilizing two feed forward artificial neural networks (FFNN) is developed to improve the performance of time series predictions.Design methodology approach - Air pollution and meteorological data were collected for one year in two locations in Kuwait. The hourly averages of the data were processed to generate a covariance matrix and analyzed to generate the principal component method. A two-FFNN model is then used to predict the actual data.Findings - The newly developed model improves the prediction accuracy over the conventional method. Owing to the presence of noise and other minor disturbances in the data, shorter-range modelling gives better modelling results.Originality value - A novel modelling technique is developed to predict the time series of zone concentration.
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CEKLJ, NUK, ODKLJ, UL, UM, UPUK
This paper focuses on modelling of emission inventory, pollutant dispersion by the industrial source complex short term model (ISCST), and neural network analysis of air pollution in Kuwait. A novel ...neural network-based scheme is suggested and applied to site-specific short- and medium-term forecasting of ozone concentrations. Two feed forward artificial neural networks (ANN) are used to improve the performance of time series predictions. Results show that this forecasting technique represents a significant improvement over the conventional ANN approach.
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BFBNIB, NUK, PILJ, SAZU, UL, UM, UPUK
The relative magnitudes of mass transfer resistances in forward osmosis and pressure retarded osmosis can be assessed by comparing the solute profiles across the bulk of the feed and draw streams. ...Three models are used to compare the relative magnitudes of the mass transfer resistances and system performance by calculating the recovery ratio, membrane area, and power density. The first model (model I) includes only the resistance of the membrane active layer, while model II includes the resistance of the solute boundary layer in the draw stream and the resistance of the membrane active and support layers. The third model (model III) includes all five resistances. The solute profiles predicted by model III for either the complete mixing (CM) or the plug flow (PF) models indicate that the membrane active layer exhibits the largest mass transfer resistances, followed by the solute boundary layer in the draw stream. All three models provide similar trends for variations in the recovery ratio, membrane area, and power density as a function of operating parameters. Predictions of the recovery ratio and the power density by the (CM) of model III showed good agreement with literature data at low inlet concentrations of the draw stream. However, the use of the (PF) of model III is necessary at higher concentrations of the draw solution. In conclusion use of the (PF) of model III gives more accurate design and simulation data at large membrane areas and high concentrations for the draw solution.
•Three models are studied to assess relative magnitude of mass transfer resistances in FO/PRO.•The major mass transfer resistance is found in the membrane active layer and the solute boundary layer on the draw side.•Trends obtained by the three models are similar, however, deviations between model III and model I can be as high as 50%.•The (PF) of model III provides more accurate design and simulation results than the (CM) approximation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Catalysts’ surface structural features and characterizations play an important role in many chemical industrial processes among which is biofuel production. Heterogeneous catalysts strongly affect ...the types of products in catalytic hydrocracking of oils. The present study aims at the preparation of low-cost inorganic catalysts with improved catalytic activity. This will then be used in the production of bio-jet fuel — conforming to ASTM specifications — by hydrocracking of
Jatropha
oil. Five types of inorganic catalysts have been prepared and tested. The best results were obtained from the catalyst produced from ceramic wastes. It produced the highest bio-jet yield (51%) and the highest freezing point (− 52 °C). A BET surface area of 21.9 m
2
/g and a "total pore volume" of 0.025877 cm
3
/g were obtained.
