http://blogs.najah.edu/author/abusafa An-Najah Blogs :: Chemical Engineering en-us Fri, 19 Apr 2024 11:47:31 IDT Fri, 19 Apr 2024 11:47:31 IDT [email protected] [email protected] http://blogs.najah.edu/staff/abusafa/article/Potential-of-Biomass-as-an-Alternative-Fuel-in-Palestine--Amounts-and-methods-of-conversionPublished Articlesthese days there is much talk about the alternative fuel and clean-burning as an alternative for petrol Palestine is known to be very poor country in terms of fossil fuel resources At the same time energy alternatives are not defined well specially the non-conventional types such as biomass Biomass can be defined as material which is recently derived from animals and plants that use sunlight to grow In this research all types and amount of biomass that exist in Palestine that can be used as an alternative fuel for petrol was analyzed and defined by a comprehensive field survey The sources of clean and alternative energy which depend on the biomass using traditional and new technologies were discussed This research aims to investigate the biomass and new process to find out a durable and a reliable alternative energy source for Palestinians All results in this study showed biomass waste can be used to produce a new energy source in the form of clean fuel and high efficiency which constitutes an alternative source for traditional fuel in several applications The most important of these applications is electricity production Final results shows 797GWh of electrical energy a can be generated annually by using biogas process from biomass residue and household solid waste and approximately 824GWh can be generated when gasification process used for the same waste http://blogs.najah.edu/staff/abusafa/article/Cooling-of-High-Heat-Flux-Electronic-Devices-by-Two-Phase-Thermosyphon-System-Published ArticlesTwo phase closed thermosyphon system for cooling high heat flux electronic devices is built in the laboratory and tested under different operating conditions This Study presents an experimental investigation on the heat transfer coefficient temperature difference between the evaporator and the refrigerant inside evaporator channels overall heat transfer coefficient and overall thermal resistance in two-phase thermosyphon system Investigations are carried out at different conditions: different system pressures two different types of refrigerants R134a and R22 two different evaporator designs natural and forced convection heat transfer mode in the condenser The heat flux and the amount of refrigerant are the manipulated parameters in the system It is found that the heat transfer coefficient increases almost linearly with the applied heat to the evaporator and reduced pressure It is also highly dependant on the type of refrigerant because the performance of the refrigerant R134a likely to be better than that of R22 The heat transfer coefficient is also higher at natural convection condensation than forced convection condensation at the same heat load while the overall heat transfer coefficient in the system for forced convection is higher than for natural convection condensation The heat transfer coefficient is highly dependant on the design of evaporator especially on the diameters channels The natural convection heat transfer coefficient is found to be 27 kWmsup2;˚C and 37 kWmsup2;˚C using R134a and R22 respectively at heat load of 115W The forced convection heat transfer coefficient is found to be 24 kWmsup2;˚C and 16 kWmsup2;˚C using R134a and R22 respectively at heat load of 450W The forced convection overall heat transfer coefficient using R134a is found to be 94 kWmsup2;˚C at 415W while it is 108 kWmsup2;˚C at natural convection at 155W The temperature difference [TevaporatorTsaturation] depends on both the applied heat flux to the evaporator systems pressure and type of the refrigerant The natural convection temperature difference does not exceed 1˚C and exceeded 8˚C for R134a and R22 respectively at heat load of 100W The obtained evaporator temperature for R134a is 94˚C at 155W and 44˚C at 414W using natural and forced convection respectively While the obtained evaporator temperature for R22 is about 80˚C at 115W and 40˚C at 450W for natural and forced convection respectively The overall thermal resistance decreases almost linearly with increasing the heat load regardless of the used refrigerant Moreover for forced convection the thermal resistance is much lower than the other heat transfer processes The overall natural convection thermal resistance is 047˚CW at 1556W and 053˚CW at 115W while overall forced convection thermal resistance is 0056˚CW at 414W and 0044˚CW at 417W for R134a and R22 refrigerants respectively http://blogs.najah.edu/staff/abusafa/article/Removal-of-Cs-137--from-aqueous-solutions-using-different-cationic-forms-of-a-natural-zeolite-clinoptilolitePublished ArticlesDistribution coefficients of cesium on natural and cation-enriched Na K NH 4 and Ca2 forms of clinoptilolite were measured by batch radioactive tracer technique The measurements were carried out for an initial cesium concentration range of 10-6-10-1 mol dm3 and at temperatures of 25 40 60 and 80 C Experimental isotherms evaluated from distribution coefficients were fit to Langmuir Freundlich and Dubinin-Radushkevich D-Rmodels Of the models tested D-R model was found to represent the isotherms better in a wider range of concentrations than either Langmuir or Freundlich model Breakthrough behavior of cesium on natural and cation-enriched forms of clinoptilolite for a particular set of conditions were also determined in a small size column Column parameters were evaluated using mass transfer zone concepthttp://blogs.najah.edu/staff/abusafa/article/Solar-Energy-Refrigeration-by-Liquid-SolidGeneral PostsThe design construction and operation of a solid adsorption solar cooler are presented in this work Granular activated carbon-methanol as the adsorbent adsorbate pair was used The System has three important components: collectoradsorber condenser and evaporator A flat plate type collector made of stainless steel with effective exposed area of 095msup2; was used Two types of condensers were tested the first one was a helical copper tube immersed in water tank and the other one was a finned stainless steel tube Solar radiation was simulated using an electrical heater regulated by a solid state relay and potentiometer The experimental work was focused on optimizing the suitable amount of activated carbonmethanol pairs the influence of regenerator temperature and the influence of solar flux on the performance of the system It was found that regenerator temperature greater than 100 C was necessary to release methanol from the activated carbon The operating pressure was also found to be an important parameter to achieve cooling effect; the system pressure must be less than 20kPa absolute As the adsorbent bed is the heart of such system and its characteristics directly affected the performance of the system the experimental work showed that the adsorbent bed which was used in this study didnt achieve the best results expected therefore another adsorbent bed with hollow tubes generator was suggested it was found that in this type of generator is easier to control the leakage and the pressure inside the system The type of the condenser and its length was found to be important parameters that affect the performance of the used system The condenser length should be as short as possible however the condenser tube should be straight pipe with fins and without any curvatures to prevent pressure drop in the system In most cases the water temperature of 10 C was obtained using the system for air-conditioning food and vaccines preservation and for producing chilled water The obtained temperature was effected directly by the heat flux applied and the heating period The optimum heating period was found to be at least 5 hours while the cooling period was more than 10 hours In a Lab scale setup solar cooler it was found that the evaporator volume has a significant effect on the performance of such system; the evaporator volume should not be much larger than the maximum methanol volume charged in the system The maximum methanol adsorption capacity of the used activated carbon was found to be 026 kg methanol kg activated carbonhttp://blogs.najah.edu/staff/abusafa/article/oxygen-enriched-combustion-of-high-emission-fuelsGeneral PostsThe main purpose of this study is to investigate the effects of using oxygen enriched combustion OEC technology with high emission fuels biodiesel and petro-diesel in different ratios on an experimental four stroke internal combustion engine ICE Volkswagen passat and a water heating boiler To do so an experimental setup was prepared for each case In both cases the intake air was enriched by injecting pure oxygen to the combustion chamber and ensure appropriate mixing before reaching the flame the highest oxygen enrichments levels are 24 in ICE and 27 in the boiler A Bacharach module 300 combustion analyzer was used in order to monitor the required oxygen enriched intake air level and to measure the combustion process emissions For internal combustion engine it has been shown that using higher intake air oxygen concentrations with pure petro-diesel fuel or blended fuel petro-diesel with biodiesel increase the exhaust gas temperature obviously the highest exhaust temperature improvement was 14 it has been achieved when using 24 O2 concentration with pure petro-diesel Also it has been shown that biodiesel fuel intensify the combustion process and improve the exhaust gas temperature due to the additional oxygen quantities contained in it results show that using B15 fuel with ambient intake air oxygen concentration 21 O2 improves the exhaust temperature 74 this temperature improvement can be assumed as an indicator of the thermal efficiency improvement However similar stack gas temperature improvement has been achieved when implementing the same experiments on water heating boiler 211 temperature improvement has been achieved when using 26 O2 intake air concentration with pure petro-diesel and optimum excess air conditions this improvement is about 38 in terms of efficiency imrpovement In addition using OEC with either the internal combustion engine or the water heating boiler affects the exhaust emissions by increasing or decreasing its quantities In ICE NOx emissions increased when using oxygen enriched intake air with blended fuel but it has been decreased when using either higher intake oxygen concentration or higher biodiesel fuel concentrations NOx emissions decreased in the water heating boiler case when operating under theoritical excess air level with respect to optimum excess air level due to the reduction in the ballast N2 entering the process Experimental results show that CO emissions decrease by using higher intake air oxygen concentrations with pure petro-diesel in both of the internal combustion engine and water heating boiler it has been clearly noticed that when operating under theoritical excess air conditions in the boiler case 772 CO emissions reduction have been achieved when using 26 O2 intake air concentration In addition CO exhaust emissions were reduced by using blended fuels higher biodiesel concentrations with ambient air oxygen concentration 21 O2 as a result of the additional oxygen quantities enter the process and improve its completeness But it has been shown that CO exhaust emissions increase in the internal combustion engine case when using higher intake air oxygen concentration with higher biodiesel fuel concentration at the same time it happened as a result of CO prompt formation results show that when using 23 O2 intake air and B15 fuel CO emissions increased 1503 with respect to using 23 O2 intake air and B0 fuel but when analyzing the same results with respect to using 21 O2 concentration with B15 fuel CO emissions increased 1045 Similarly SO2 emissions did not change when using OEC technology or biodiesel fuel in the ICE but when operating under theoretical excess air conditions in the boiler section SO2 emissions were very high and it has been reduced by using oxygen enriched intake air andor biodiesel fuelhttp://blogs.najah.edu/staff/abusafa/article/Methodology-for-Disinfectant-Dose-Evaluation-Modelling-and-Optimization-in-Drinking-Water-in-Small-Middle-Eastern-Cities---Nablus-City-Palestine-as-a-Case-StudyGeneral PostsThe City of Nablus relies on groundwater resources for water supply Water is collected in central reservoirs and later distributed to the designated areas through a water distribution network Due to the expansiveness of the network the remoteness of the water sources and the weariness in the network pipes and joints chlorine concentrations were found to be way below the minimum allowable limits This study investigated the disinfection problems that exist in the water network of Nablus A composite database for the last 9 years 1996-2005 was created to facilitate the spatial and temporal assessment Assessment of the current chlorination practice for a selected area within the Nablus drinking water network was carried out through a development of water network quality model using the GIS technology and EPANET The model simulates the water flow in pipes pressure at the supply nodes and chlorine concentration distribution in pipes and nodes Results of the analysis of the composite database showed that residual chlorine concentrations in many areas were low This has led to the bacterial growth in these areas as indicated by total and fecal coliform readings Model outcome showed that chlorine concentration varies from location to location in the network which is in agreement with field observations This model could then be used by the Municipality to determine the optimal chlorine dose such that chlorine concentration distribution across the network is within the acceptable limits http://blogs.najah.edu/staff/abusafa/article/CONVERSION-OF-ANIMAL-FATS-INTO-BENEFICIAL-PRODUCTS-General Posts The importance of animal fats as useful and cheap raw material is considered Animal by-products including animal fats are dumped in revolting view around slaughter houses and in solid waste dumping sites This work gives attention to exploit the animal fat and convert it to many economical articles The application of it as alternative fuel is not suggested Experiments are carried out with methanol and ethanol to produce biodiesel The total conversion needs large amounts of these expensive solvents with energy In stead manufacturing of soap candles rubber plastics lubricants crayons waxes cleaners and personal care products buffing compounds greases and various chemical derivatives should be considered Or simply using it in animal feeding and dust reduction