سنتز و بررسي عملكرد نانو لوله هاي كربني ايجاد كننده احتراق

چكيده انگليسي :

Synthesis and Investigation of Carbon Nanotubes as an Ignition Agent Narges Mohammadian n mohammadian@ce iut ac ir 30 4 2011 Department of Chemical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor S M Ghoreishi ghoreshi@cc iut ac ir M Ghiaci mghiaci@cc iut ac irAbstractCarbon nanotubes CNTs attracted a lot of attention because of their unique structures and special properties Since their discovery different production methods have been introduced to synthesize CNTs The main goal isto obtain a synthesis method which be economical high quality productions controllable and capacity toproduct carbon nanotubes in large scale In this thesis floating catalyst chemical vapor deposition was usedbecause of lots of its advantages like the ability to use in industries synthesis unmixed carbon nanotubes andcontrol the kind of CNTs by controlling synthesis parameters Xylene ferrocene thiophene and hydrogen gaswere used as the carbon precursor catalyst promoter and carriergas respectively In order to make meaningfultests and obtain process optimization response surface design and analysis by design expert7 software andcentral composite design CCD was used Since the diameter of reactor was constant during the tests catalystconcentration temperature and carriergas flow was selected as the main parameters and in the 1 6 wt 800 1200 9C and 160 280 ml min regins respectively tests were Designed in five levels according to the definedarea for each parameter The results of analysis by Raman specrophotometry of synthesized samples showedthat the effect of increasing temperature hydrogen concentration and flow of hydrogen gas on the quality ofsynthesized carbon nanotubes is increasing reduction Also optimal operation conditions is in the areabetween of defined ranges Mathematical models of carbon nanotubes quality as a second degree of relationshipof the three factors was obtained Comparison of model results and experimental data reveal that the model canpredicate the system behavior well and the only parameters which are unsignificant in the model is theinteraction between terms By using model and design expert7 software optimal points of synthesis parametersare achieved in catalyst concentration 3 79wt temperature 9769C and flow of hydrogen 184 ml min In orderto obtain the reduction of core growth agglomeration in the nanotube synthesis stage and optimum conditions thiophene was used to prevent agglometate cores by space prevented since the high concentration of sulfurcauses toxic catalyst therefore in optimal conditions of temperature concentration and flow severalexperiments with different concentration of thiophene was done and Thermo Gravimetric Analysis TGA reveal that the best amount of thiophene concentration is 2 5wt The second part of this thesis is related to anovel ignition method that uses a single exposure of an ordinary camera flash and SWCNTs to ignite variousfuels The effects of the iron Fe nanoparticles embedded in the SWCNTs concentration and the frequency offlash light on the ignition process have been studied by design expert7 software and central composite design CCD The region of Independent parameters of 10 50wt and 1 5Hz were seleted The results reveal that inhigh concentration of iron impurity and low frequency carbon nanotubes were more oxidized Mathematicalmodel of carbon nanotubes quality as a second degree of relationship of the three factors was obtained Comparison of model results and experimental data reveal that the model can predict the system behavior well Keywords carbon nanotubes floating catalyst chemical vapor deposition ferrocene ignition response surfacedesign and analysis central composite design

محمديان، نرگس

سنتز و بررسي عملكرد نانو لوله هاي كربني ايجاد كننده احتراق

رسوب دهي بخار شيميايي , شناور سازي كاتاليست , فروس , نورفلش , مدلسازي رياضي , رويه پاسخ