The current conflict in Syria is attracting an unprecedented amount of foreign fighters who have ... more The current conflict in Syria is attracting an unprecedented amount of foreign fighters who have travelled there to join the rebels. Given the high and immediate policy relevance of the topic, the kinds of knowledge we have at the moment on foreign fighters is in the majority empirical and descriptive, rather than analytical and theoretical. So far, studies have gathered data on the numbers of foreign fighters having left Europe or the West in general (or more rarely countries in the Middle East), and their demographic and socio-economic profiles, as well as mapped the propaganda and recruitment strategies of the IS and affiliated disseminators, including the foreign fighters themselves. Efforts have also been undertaken towards establishing a definition of foreign fighters, notably as different to that of terrorists. Far less known are the reasons behind both the travel to, and the return from Syria, i.e. individual motivations. This is not due to a lack of interest in this topic, ...
This study aims to optimize the velocity of ring shape parameter for designing the nozzles using ... more This study aims to optimize the velocity of ring shape parameter for designing the nozzles using computational fluid dynamics (CFD) and investigated the flow in nozzles using ANSYS, Inc. simulation software. The model geometries were defined using ANSYS FLUENT-Design Modeler platform. All nozzles were designed on unstructured triangular elements comprising of 1200000 mesh nodes. The differential governing equations were applied in ANSYS FLUENT based on a finite volume method. The distance and dimensions of ring location significantly influence the velocity of water during flow where the maximum velocity at double rings reduces the surface area at distance of 7mm and 15mm and 2x2 mm dimensions. Considering 8, 10, and 12 bar liner proportions, there was an increase in the velocity at maximum points in ring shapes.
The study aims to determine the effect of nozzle groove on fluid flow through viscous 2D planar f... more The study aims to determine the effect of nozzle groove on fluid flow through viscous 2D planar fluid. To fulfil the study’s aim, numerical method was adopted to introduce grooves of different dimensions from the nozzle exit. The study adopts SoldWork software was used to design nozzles and introduce groove shaped nozzles, each consisting of six different designs. The nozzle base model used in this study was similar to the one used in a previous study. The procedure was performed with different pressures (8, 10, and 12 bar) at the similar firefighting nozzle. The velocities contours were predicted based on the choice of nozzle section during the numerical stimulation. The results of present study demonstrated a new approach that can be used for increasing velocity at various types of modified nozzles through grooves at different pressures and locations. For grooves, dimensions 1×1 (mm) and location 15 mm at 8 bar, 10 bar and 12 bars showed no effect on velocity as it reduces velocit...
Considerable amount of oily waste is generated from petroleum refinery in Malaysia. A typical ref... more Considerable amount of oily waste is generated from petroleum refinery in Malaysia. A typical refinery produces about 40 tons of sludge per month. Disposing via land filling (common method) is becoming less accepted and more expensive. As a result, refineries and other facilities have accumulated large volumes of this waste in makeshift landfills or other storage areas. For this reason solvent extraction method has been selected for oil recovery and to minimize the solid waste. Three solvents (chloroform, MEK, and n-hexane) and two extraction methods (sludge–solvent mixing method , and Soxhlet apparatus) were applied to recover the oil from the refinery sludge. Soxhlet extraction method has shown higher efficiency in extraction than sludge-solvent mixing method. Soxhlet extraction method using MEK solvent can recover about 48.3 % of oil, as compared to mixing method which accounts to only about 32.5 % of recovered oil. It has an added recovery of about 7.1 %, 15.8 % and 5.7 % for n-...
Limited information is available about the thermodynamic evaluation for biomass gasification proc... more Limited information is available about the thermodynamic evaluation for biomass gasification process using updraft gasifier. Therefore, to minimize errors, the gasification of dry refinery sludge (DRS) is carried out in adiabatic system at atmospheric pressure under ambient air conditions. The objectives of this paper are to investigate the physical and chemical energy and exergy of product gas at different equivalent ratios (ER). It will also be used to determine whether the cold gas, exergy, and energy efficiencies of gases may be maximized by using secondary air injected to gasification zone under various ratios (0, 0.5, 1, and 1.5) at optimum ER of 0.195. From the results obtained, it is indicated that the chemical energy and exergy of producer gas are magnified by 5 and 10 times higher than their corresponding physical values, respectively. The cold gas, energy, and exergy efficiencies of DRS gasification are in the ranges of 22.9–55.5%, 43.7–72.4%, and 42.5–50.4%, respectively...
Many papers have been published about the gasification of different biomass fuels in fixed bed re... more Many papers have been published about the gasification of different biomass fuels in fixed bed reactor. To date, no experimental analysis is available in the open literature on gasification of refinery sludge. Therefore the descriptions of dynamic temperature in an updraft reactor for a dry refinery sludge gasification are investigated in details. The rate of the temperature change with operation time and the temperature profiles inside the reactor are taken for various equivalent ratios. The dynamic results show that increasing the ER from 0.195 to 0.244 shift the combustion zone peak temperature from 858 °C to 986 °C and cause turbulence behavior in reduction zone temperature. With an ER of 0.195, the rate change of temperatures zones was found to be in the ± 50 OC min-1 indicating stable gasification process. The axial temperature for starting of a steady state gasification process was found to be between 20 to 60 min operation time in process.
The study probes into the investigation on gasification of dry refinery sludge. The details of th... more The study probes into the investigation on gasification of dry refinery sludge. The details of the study includes; influence of operation time, oxidation temperature and equivalence ratios on carbon gas conversion rate, gasification efficiency, heating value and fuel gas yield are presented. The results show that, the oxidation temperature increased sharply up to 858°C as the operating time increased up to 36 min then bridging occurred at 39 min which cause drop in reaction temperature up to 819 °C. This bridging was found to affect also the syngas compositions, meanwhile as the temperature decreased the CO, H2, CH4 compositions are also found to be decreases. Higher temperature catalyzed the reduction reaction (CO2+C = 450 2CO), and accelerated the carbon conversion and gasification efficiencies, resulted in more solid fuel is converted to a high heating value gas fuel. The equivalence ratio of 0.195 was found to be the optimum value for carbon conversion and cold gas efficiencies, high heating value of ...
The current conflict in Syria is attracting an unprecedented amount of foreign fighters who have ... more The current conflict in Syria is attracting an unprecedented amount of foreign fighters who have travelled there to join the rebels. Given the high and immediate policy relevance of the topic, the kinds of knowledge we have at the moment on foreign fighters is in the majority empirical and descriptive, rather than analytical and theoretical. So far, studies have gathered data on the numbers of foreign fighters having left Europe or the West in general (or more rarely countries in the Middle East), and their demographic and socio-economic profiles, as well as mapped the propaganda and recruitment strategies of the IS and affiliated disseminators, including the foreign fighters themselves. Efforts have also been undertaken towards establishing a definition of foreign fighters, notably as different to that of terrorists. Far less known are the reasons behind both the travel to, and the return from Syria, i.e. individual motivations. This is not due to a lack of interest in this topic, ...
This study aims to optimize the velocity of ring shape parameter for designing the nozzles using ... more This study aims to optimize the velocity of ring shape parameter for designing the nozzles using computational fluid dynamics (CFD) and investigated the flow in nozzles using ANSYS, Inc. simulation software. The model geometries were defined using ANSYS FLUENT-Design Modeler platform. All nozzles were designed on unstructured triangular elements comprising of 1200000 mesh nodes. The differential governing equations were applied in ANSYS FLUENT based on a finite volume method. The distance and dimensions of ring location significantly influence the velocity of water during flow where the maximum velocity at double rings reduces the surface area at distance of 7mm and 15mm and 2x2 mm dimensions. Considering 8, 10, and 12 bar liner proportions, there was an increase in the velocity at maximum points in ring shapes.
The study aims to determine the effect of nozzle groove on fluid flow through viscous 2D planar f... more The study aims to determine the effect of nozzle groove on fluid flow through viscous 2D planar fluid. To fulfil the study’s aim, numerical method was adopted to introduce grooves of different dimensions from the nozzle exit. The study adopts SoldWork software was used to design nozzles and introduce groove shaped nozzles, each consisting of six different designs. The nozzle base model used in this study was similar to the one used in a previous study. The procedure was performed with different pressures (8, 10, and 12 bar) at the similar firefighting nozzle. The velocities contours were predicted based on the choice of nozzle section during the numerical stimulation. The results of present study demonstrated a new approach that can be used for increasing velocity at various types of modified nozzles through grooves at different pressures and locations. For grooves, dimensions 1×1 (mm) and location 15 mm at 8 bar, 10 bar and 12 bars showed no effect on velocity as it reduces velocit...
Considerable amount of oily waste is generated from petroleum refinery in Malaysia. A typical ref... more Considerable amount of oily waste is generated from petroleum refinery in Malaysia. A typical refinery produces about 40 tons of sludge per month. Disposing via land filling (common method) is becoming less accepted and more expensive. As a result, refineries and other facilities have accumulated large volumes of this waste in makeshift landfills or other storage areas. For this reason solvent extraction method has been selected for oil recovery and to minimize the solid waste. Three solvents (chloroform, MEK, and n-hexane) and two extraction methods (sludge–solvent mixing method , and Soxhlet apparatus) were applied to recover the oil from the refinery sludge. Soxhlet extraction method has shown higher efficiency in extraction than sludge-solvent mixing method. Soxhlet extraction method using MEK solvent can recover about 48.3 % of oil, as compared to mixing method which accounts to only about 32.5 % of recovered oil. It has an added recovery of about 7.1 %, 15.8 % and 5.7 % for n-...
Limited information is available about the thermodynamic evaluation for biomass gasification proc... more Limited information is available about the thermodynamic evaluation for biomass gasification process using updraft gasifier. Therefore, to minimize errors, the gasification of dry refinery sludge (DRS) is carried out in adiabatic system at atmospheric pressure under ambient air conditions. The objectives of this paper are to investigate the physical and chemical energy and exergy of product gas at different equivalent ratios (ER). It will also be used to determine whether the cold gas, exergy, and energy efficiencies of gases may be maximized by using secondary air injected to gasification zone under various ratios (0, 0.5, 1, and 1.5) at optimum ER of 0.195. From the results obtained, it is indicated that the chemical energy and exergy of producer gas are magnified by 5 and 10 times higher than their corresponding physical values, respectively. The cold gas, energy, and exergy efficiencies of DRS gasification are in the ranges of 22.9–55.5%, 43.7–72.4%, and 42.5–50.4%, respectively...
Many papers have been published about the gasification of different biomass fuels in fixed bed re... more Many papers have been published about the gasification of different biomass fuels in fixed bed reactor. To date, no experimental analysis is available in the open literature on gasification of refinery sludge. Therefore the descriptions of dynamic temperature in an updraft reactor for a dry refinery sludge gasification are investigated in details. The rate of the temperature change with operation time and the temperature profiles inside the reactor are taken for various equivalent ratios. The dynamic results show that increasing the ER from 0.195 to 0.244 shift the combustion zone peak temperature from 858 °C to 986 °C and cause turbulence behavior in reduction zone temperature. With an ER of 0.195, the rate change of temperatures zones was found to be in the ± 50 OC min-1 indicating stable gasification process. The axial temperature for starting of a steady state gasification process was found to be between 20 to 60 min operation time in process.
The study probes into the investigation on gasification of dry refinery sludge. The details of th... more The study probes into the investigation on gasification of dry refinery sludge. The details of the study includes; influence of operation time, oxidation temperature and equivalence ratios on carbon gas conversion rate, gasification efficiency, heating value and fuel gas yield are presented. The results show that, the oxidation temperature increased sharply up to 858°C as the operating time increased up to 36 min then bridging occurred at 39 min which cause drop in reaction temperature up to 819 °C. This bridging was found to affect also the syngas compositions, meanwhile as the temperature decreased the CO, H2, CH4 compositions are also found to be decreases. Higher temperature catalyzed the reduction reaction (CO2+C = 450 2CO), and accelerated the carbon conversion and gasification efficiencies, resulted in more solid fuel is converted to a high heating value gas fuel. The equivalence ratio of 0.195 was found to be the optimum value for carbon conversion and cold gas efficiencies, high heating value of ...
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