1,721,307 research outputs found
FUEL PROCESSING: MODELLING AND STRUCTURED CATALYTIC REACTORS
No full textEnergy consumption is the important component in the debates of global climate change and sustainable energy future. According to International Energy Agency, world energy consumption will rise by 56% from 2010 to 2050 with 80% share of fossil fuels resulting in increased emissions of greenhouse gases. Research & development is required to supply clean fuel, increase efficiency of energy utilization and eliminate pollutant emissions. Renewable energy (solar, wind etc.,) systems are important but their penetration in the vast existing energy system is slow, painful and highly uncertain. Hydrogen is the proposed solution to future energy availability, environmental challenges and developing new energy industry. Hydrogen is an energy carrier like electricity; can be produced from renewable and non-renewable energy resources (natural gas, petroleum, coal etc.,) through water electrolysis, reforming, gasification etc. Transition from fossil fuel based energy systems to hydrogen based energy systems involves significant scientific, technological and socioeconomic barriers. Hydrogen produced from fossil fuels through fuel processing can be used for stationary and mobile fuel cell based applications and additionally will help to develop hydrogen infrastructure due to its availability at acceptable cost from the existing wide network. Small scale natural gas and petroleum reformers and hydrogen purification technologies represent an important technology for hydrogen production to create hydrogen filling stations that will help for transition to larger hydrogen supply. The doctoral thesis is focused on: (1) modelling in Aspen plus to compare different standalone fuel processor and integrated with auxiliary power unit for syngas and electricity production; (2) preparation, characterization and testing of structured catalytic reactors (monoliths, foams and plate reactor) for methane steam reforming. Chapter 1 describes the introductory materials of fuel processing and structured catalytic reactors. In chapter 2, the performance of the CO preferential oxidation (PROX) process was compared with the CO selective methanation (SMET) one, both applied as the last clean-up process step of a fuel processor unit (FPU) to remove CO from syngas. The FPU was completed with the reformer (autothermal reformer ATR or steam reformer SR) and a non-isothermal water gas shift (NI-WGS) reactor. Furthermore, the reforming of different hydrocarbon fuels, among those most commonly found in service stations (gasoline, light diesel oil and compressed natural gas) was examined. The comparison, in terms of different FPU configurations and fuels, was carried out by a series of steady-state system simulations in Aspen Plus®. In chapter 3, the performances of four different auxiliary power unit (APU) schemes, based on a 5 kWe net proton exchange membrane fuel cell (PEM-FC) stack, are evaluated and compared. The fuel processor section of each APU is characterized by a reformer (autothermal ATR or steam SR), a non-isothermal water gas shift (NI-WGS) reactor and a final syngas catalytic clean-up step: the CO preferential oxidation (PROX) reactor or the CO selective methanation (SMET) one. Furthermore, three hydrocarbon fuels, the most commonly found in service stations (gasoline, light diesel oil and natural gas) are considered as primary fuels. The comparison is carried out examining the results obtained by a series of steady-state system simulations in Aspen Plus® of the four different APU schemes by varying the fed fuel. In chapter 4, performance of Ru/La-Al2O3 catalysts was evaluated over different structures monoliths and foams for methane steam reforming. Structures of different materials, cpsi/ppi were prepared and characterized with different loadings of 1.5%Ru/3%La-Al2O3 catalyst and tested to find optimum loading at S/C of 3.0 with different temperatures and weight hourly space velocity (WHSV). Preparation and characterization of catalyst coated structures were carried out in University of Basque Country, San Sebastian Spain and experimentations were performed in Politecnico di Torino, Italy. In chapter 5, catalyst (5%Pt/Al2O3) preparation, characterization and experimentations were performed to couple methane steam reforming and combustion on alternate side of catalyst (5%Pt/Al2O3) coated plate reactor. Preliminary experimentations were performed to find out the most active side to use for methane steam reforming. Then, performance of catalytic plate reactor was evaluated by coupling both reactions in co-current and counter-current flow arrangement
Development and Deployment of an Unmanned Aerial Vehicle-based Traffic Analysis System
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Development and Deployment of an Unmanned Aerial Vehicle-based Traffic Analysis System
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Mitigation of road traffic crash hazard in Pakistan
No full textPurpose - Road traffic crashes (RTCs) result in creating significant social and economic hazard for affectees, their families and society. The purpose of this paper is to present studies which were conducted to study the patterns of RTCs in Karachi which is a metropolitan city of Pakistan. The studies were conducted on one of the busiest roads in the city named as Shara-e-Faisal. The influence and contribution of different factors in RTCs has been studied and hazardous road sections of Shara-e-Faisal have been identified. Based on the data analysis, an evaluation model has been suggested to reduce the hazard of RTCs on Shara-e-Faisal. The objective of the presented studies is to increase the present level of safety of road travel by reducing crashes on Shara-e-Faisal. Design/methodology/approach - Existing data of RTCs in Karachi have been analysed for the presented studies. For this purpose, Shara-e-Faisal was divided in sections of 1 km length to study the vehicle crash pattern. Location surveys were conducted to record physical conditions of this road. A cluster analysis was carried out to identify hazardous sections of the road. An evaluation model has been suggested in the end to reduce the hazard of RTCs by identifying hazardous road sections of Shara-e-Faisal. Findings - The analysis of the data revealed that the crashes were higher over weekend and on Monday. Male population, particularly young people, and motorcycle riders were the largest affectees of RTCs. In general, more daytime crashes were recorded as compared to nighttime crashes. The crashes in the mid block of the road and those involving rear-end collisions were higher. The hazardous road locations were related to poor road conditions. Statistical analysis indicated that alternate routes were required to reduce the RTC hazard on Shara-e-Faisal. Research limitations/implications - The paper is a small, but an original, contribution to identify a potential hazard which is faced by the community in the city. This is the first attempt (to the best of authors' knowledge) to address the issue of RTCs in Karachi from an engineering view point. Practical implications -The suggested model can be employed by the authorities as a guideline to mitigate the hazard of road crashes in the country. Originality/value - The paper provides valuable information on the road traffic incidents, their pattern and contributing factors in one of the largest metropolis of Pakistan. The suggested model can become helpful in reducing RTCs in Pakistan
Performance evaluation and comparison of fuel processors integrated with PEM fuel cell based on steam or autothermal reforming and on CO preferential oxidation or selective methanation
No full textThe performances of four different auxiliary power unit (APU) schemes, based on a 5 kWe net proton exchange membrane fuel cell (PEM-FC) stack, are evaluated and compared. The fuel processor section of each APU is characterized by a reformer (autothermal ATR or steam SR), a non-isothermal water gas shift (NI-WGS) reactor and a final syngas catalytic clean-up step: the CO preferential oxidation (PROX) reactor or the CO selective methanation (SMET) one. Furthermore, three hydrocarbon fuels, the most commonly found in service stations (gasoline, light diesel oil and natural gas) are considered as primary fuels. The comparison is carried out examining the results obtained by a series of steady-state system simulations in Aspen Plus® of the four different APU schemes by varying the fed fuel. From the calculated data, the performance of CO-PROX is not very different compared to that of the CO-SMET, but the performance of the SR based APUs is higher than the scheme of the ATR based APUs. The most promising APU scheme with respect to an overall performance target is the scheme fed with natural gas and characterized by a fuel processor chain consisting of SR, NI-WGS and CO-SMET reactors. This processing reactors scheme together with the fuel cell section, notwithstanding having practically the same energy efficiency of the scheme with SR, NI-WGS and CO-PROX reactors, ensures a less complex scheme, higher hydrogen concentration in the syngas, lower air mass rate consumption, the absence of nitrogen in the syngas and higher potential power of the stack anode exhaust. The stack anode exhaust, in fact, is recycled to the fuel processor section, thanks to the presence of methane produced in the final clean-up methanation reacto
Sensitivity and economical analysis of fuel processors based on SR integrated with WGS and PSA for pure hydrogen production from natural gas
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Final step for CO syngas clean-up: comparison between CO-PROX and CO-SMET processes
No full textThe performance of the CO preferential oxidation (PROX) process was compared with the CO selective methanation (SMET) one, both applied as the last clean-up process step of a fuel processor unit (FPU) to remove CO from syngas. The FPU was completed with the reformer (autothermal reformer ATR or steam reformer SR) and a non-isothermal water gas shift (NI-WGS) reactor. Furthermore, the reforming of different hydrocarbon fuels, among those most commonly found in service stations (gasoline, light diesel oil and compressed natural gas) was examined. The comparison, in terms of different FPU configurations and fuels, was carried out by a series of steady-state system simulations in Aspen Plus®. From the obtained data, the performance of CO-PROX was not very different from that of CO-SMET, making it complex to give a definitive answer on the best FPU scheme. The most promising fuel processor with respect to performance is a chain of ATR, NI-WGS and CO-SMET. However, maintaining the same chain of clean-up reactors, the FPU with SR instead of ATR could also be a satisfactory choice. Even if there are lower efficiencies and H2 specific production compared to the ATR-based FPU, the SR-based one does not produce a syngas with the high N2 concentration typical of the ATR-based FPU. The syngas dilution by nitrogen is somehow detrimental for the stack efficiency, when syngas feeds PEM-FCs, since it lowers the polarization curv
Performance of SR or ATR fuel processors integrated with WGS and PSA units for hydrogen production
No full textInsight into effect of catalyst loading on methane steam reforming and controlling regime in metallic catalytic monoliths
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