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The thermal response of a pressurised storage vessel and its contents to simulated jet fire impingementLacy, Clive B. January 1997 (has links)
The storage of pressure liquefied gas in vessels is subject to various regulations and codes of practice. For example, Liquefied Petroleum Gas (LPG), a commercially relevant product, is subject to Health and Safety Executive Guidelines regarding cylinder/tank arrangements and spacing. In the event of an incident involving fire, the internal pressure and shell temperature of an LPG vessel will rise, and the weakening of steel at elevated temperatures can result in the structural failure of the shell. This can be avoided by the fitting of pressure relief valves, which vent material at a pre-set pressure. However, an ignited release can create a high velocity jet flame which, because of significant radiative and convective components, can generate intense, localised heat loads on neighbouring vessels or pipe-work. However, existing codes of practice have no special provision for the possibility of jet fire incidents. Owing to a lack of detailed information on the thermal response of a LPG vessel exposed to jet flame impingement, a series of laboratory scale tests with simulated, localised jet fire impingement on the exterior shell of a pressure vessel was required. The thermal response and the effects of key parameters, Le. fill level, magnitude of heated zone (Le. size and intensity) and position of simulated impingement, could then be examined for the part-validation of a suitable computer model. In addition, these studies could be used to interpret the results from concurrent full scale jet fire impingement trials. An appropriate pressure vessel was constructed to standard design codes, which incorporated a vent line and dump tank. A suitable LPG substitute was selected. Results from the studies indicated that mixing, and therefore thermal stratification, was highly dependent on the size of the heated zone and its position in relation to the liquid/vapour interface. High Speed Micro-Cinematography was successfully employed to film individual bubble streams within the vessel and to measure individual bubble sizes and velocities for various experimental configurations. Studies were also made on the venting characteristics. Sudden pressure relief caused severe agitation of the liquid phase and the breakdown of thermal stratification. In addition, swelling and aerosol generation through homogenous boiling within the liquid phase was observed. Comparisons with the nodal computer model revealed that the use of only single vapour and liquid nodes was a poor approximation to the detail observed in the small scale studies, where the incident heat flux was relatively low and the simulated region of impingement was highly localised. However, the bulk liquid and vapour temperatures and the pressure response up to the time of venting was generally well predicted. As the degree of engulfment increased the model became a better approximation. Although the full scale trials employed an almost fully engulfing jet flame rather than point source impingement, comparisons have allowed understanding of the liquid and vapour thermal gradients, and the subsequent breakdown of these during venting.
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Hydrogen Production from Liquefied Petroleum Gas (LPG) by Oxidative Steam Reforming Over Bimetallic CatalystsMalaibari, Zuhair January 2011 (has links)
Hydrogen is a promising renewable fuel for producing energy in transportation and domestic applications. This study investigates the production of H2 from reforming of liquefied petroleum gas (LPG). LPG is a mixture of gases, mainly propane and butane, produced from petroleum or natural gas. It is a liquid under moderate pressure and therefore a favourable feedstock for distributed hydrogen production since it is easy to store and transport with a distribution network already in place. With its wide range of propane and butane compositions world wide, in this study LPG was considered as a mixture of propane and butane. H2 production from LPG was investigated through oxidative steam reforming of propane and butane.
Oxidative steam reforming (OSR) can be viewed as a combination of two reactions: partial oxidation (PO) and steam reforming (SR). By carefully controlling the steam to carbon (S/C) and oxygen to carbon (O2/C) ratios in the feed, OSR can produce higher H2 yields than PO at operational temperatures lower than SR.
In the first part of this study, based on the literature and preliminarily experiments, two Ni based bimetallic catalysts, Pt-Ni/Al2O3 and Mo-Ni/Al2O3, were selected to be compared to a monometallic 15 wt% Ni/Al2O3 catalyst for OSR of a 1:1 propane to butane LPG mixture under different operational conditions. This catalysts screening study evaluated the performance of the catalysts on the basis of a statistical factorial experimental design. The factorial design was efficient in optimizing experimental runs, while testing the activity and product distribution of the catalysts at different operational limits. The importance of the factorial design was clearer when analyzing results for the Pt-Ni catalysts, as the catalyst showed different product compositions at the two selected loadings (0.2 and 1 wt%) under different conditions compared to the unpromoted catalyst. However, at both loadings, the Pt-Ni catalyst did not have a significant effect on fuel conversion or catalyst selectivity to different products. On the other had, under all stable conditions in the factorial design experiments, the Ni-Mo catalyst had higher H2 and CO yields and lower CH4 yields compared to the unpromoted catalyst. To our knowledge these product composition variations were not reported before in the literature for hydrocarbon reforming reactions over Mo promoted catalysts.
The catalyst screening study also included time on stream catalysts stability tests. These experiments illustrated the high potential for solving the Ni stability problem associated with LPG reforming as the unpromoted 15Ni catalyst suffered from deactivation by coking and could not sustain its high conversion. On the other hand, promoting the Ni catalysts with 1 wt% Pt or 0.1 wt% Mo improved the catalyst resistance to coking and sustained its activity and product composition throughout the 18 hours of the stability tests. However, an increase in the Mo loading to 0.3 wt% in the Mo-Ni bimetallic catalyst, led to lower fuel conversions and loss of stability with time.
Because of the interesting performance of the Mo-Ni /Al2O3 catalyst observed in the catalyst screening tests, and the lack of explanations of different aspects of this performance in the literature, especially in the presence of O2, the second part of the study was concerned with the investigation of the effect of small amounts of Mo addition on the activity, selectivity and stability of Ni catalysts when used for H2 production from LPG OSR. Individual fuels and reactions experiments showed that butane OSR gave the highest fuel conversions and H2 production rates. These experiments also revealed the importance of O2 for the catalyst activity and stability as for both hydrocarbons the catalyst suffered deactivation by coking under SR conditions. However, O2 compositions in the feed should be carefully optimized as characterization of fresh and aged catalysts showed that the loss of stability observed earlier in the catalyst screening tests for higher Mo catalysts loading, was caused by the oxidation of active Ni species to inactive Ni and Ni-Mo phases which resulted from the oxidative environment of the reaction during aging.
In the last part of this study, surface and bulk properties of the monometallic Ni catalyst was compared to the Mo-Ni bimetallic catalyst using different catalyst characterization techniques ( TPR, TPO, TGA, XRD, H2 and O2 chemisorption and DRIFTS) in order to understand the structural effect of Mo addition on the catalytic properties. It was found that the improvements in the catalytic properties of the catalyst and the change in its selectivity to different products were caused by an electronic effect of Mo and its different oxide phases on Ni species. These electronic effects enhanced the O2 mobility over the catalysts surface leading to higher gasification rates of CHx species and hence, preventing coking of the catalyst. They also affected the stability of adsorbed reaction intermediates over the catalysts surface which affected the selectivity of the catalyst to different reaction products.
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Hydrogen Production from Liquefied Petroleum Gas (LPG) by Oxidative Steam Reforming Over Bimetallic CatalystsMalaibari, Zuhair January 2011 (has links)
Hydrogen is a promising renewable fuel for producing energy in transportation and domestic applications. This study investigates the production of H2 from reforming of liquefied petroleum gas (LPG). LPG is a mixture of gases, mainly propane and butane, produced from petroleum or natural gas. It is a liquid under moderate pressure and therefore a favourable feedstock for distributed hydrogen production since it is easy to store and transport with a distribution network already in place. With its wide range of propane and butane compositions world wide, in this study LPG was considered as a mixture of propane and butane. H2 production from LPG was investigated through oxidative steam reforming of propane and butane.
Oxidative steam reforming (OSR) can be viewed as a combination of two reactions: partial oxidation (PO) and steam reforming (SR). By carefully controlling the steam to carbon (S/C) and oxygen to carbon (O2/C) ratios in the feed, OSR can produce higher H2 yields than PO at operational temperatures lower than SR.
In the first part of this study, based on the literature and preliminarily experiments, two Ni based bimetallic catalysts, Pt-Ni/Al2O3 and Mo-Ni/Al2O3, were selected to be compared to a monometallic 15 wt% Ni/Al2O3 catalyst for OSR of a 1:1 propane to butane LPG mixture under different operational conditions. This catalysts screening study evaluated the performance of the catalysts on the basis of a statistical factorial experimental design. The factorial design was efficient in optimizing experimental runs, while testing the activity and product distribution of the catalysts at different operational limits. The importance of the factorial design was clearer when analyzing results for the Pt-Ni catalysts, as the catalyst showed different product compositions at the two selected loadings (0.2 and 1 wt%) under different conditions compared to the unpromoted catalyst. However, at both loadings, the Pt-Ni catalyst did not have a significant effect on fuel conversion or catalyst selectivity to different products. On the other had, under all stable conditions in the factorial design experiments, the Ni-Mo catalyst had higher H2 and CO yields and lower CH4 yields compared to the unpromoted catalyst. To our knowledge these product composition variations were not reported before in the literature for hydrocarbon reforming reactions over Mo promoted catalysts.
The catalyst screening study also included time on stream catalysts stability tests. These experiments illustrated the high potential for solving the Ni stability problem associated with LPG reforming as the unpromoted 15Ni catalyst suffered from deactivation by coking and could not sustain its high conversion. On the other hand, promoting the Ni catalysts with 1 wt% Pt or 0.1 wt% Mo improved the catalyst resistance to coking and sustained its activity and product composition throughout the 18 hours of the stability tests. However, an increase in the Mo loading to 0.3 wt% in the Mo-Ni bimetallic catalyst, led to lower fuel conversions and loss of stability with time.
Because of the interesting performance of the Mo-Ni /Al2O3 catalyst observed in the catalyst screening tests, and the lack of explanations of different aspects of this performance in the literature, especially in the presence of O2, the second part of the study was concerned with the investigation of the effect of small amounts of Mo addition on the activity, selectivity and stability of Ni catalysts when used for H2 production from LPG OSR. Individual fuels and reactions experiments showed that butane OSR gave the highest fuel conversions and H2 production rates. These experiments also revealed the importance of O2 for the catalyst activity and stability as for both hydrocarbons the catalyst suffered deactivation by coking under SR conditions. However, O2 compositions in the feed should be carefully optimized as characterization of fresh and aged catalysts showed that the loss of stability observed earlier in the catalyst screening tests for higher Mo catalysts loading, was caused by the oxidation of active Ni species to inactive Ni and Ni-Mo phases which resulted from the oxidative environment of the reaction during aging.
In the last part of this study, surface and bulk properties of the monometallic Ni catalyst was compared to the Mo-Ni bimetallic catalyst using different catalyst characterization techniques ( TPR, TPO, TGA, XRD, H2 and O2 chemisorption and DRIFTS) in order to understand the structural effect of Mo addition on the catalytic properties. It was found that the improvements in the catalytic properties of the catalyst and the change in its selectivity to different products were caused by an electronic effect of Mo and its different oxide phases on Ni species. These electronic effects enhanced the O2 mobility over the catalysts surface leading to higher gasification rates of CHx species and hence, preventing coking of the catalyst. They also affected the stability of adsorbed reaction intermediates over the catalysts surface which affected the selectivity of the catalyst to different reaction products.
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Analýza využití alternativních pohonů na příkladu podnikatelského záměru / The analysis of alternative fuels on example of business planKlimeš, Pavel January 2010 (has links)
The theme of the diploma thesis is to analyze the use and prepare the business plan of establishing alternative fuel showroom cars. Showroom will focus on sales of new cars with full warranty that are primary equipped with alternative fuel engine. The idea of concentrating sales center of alternative fuel cars is unique, in the vast majority of cases sellers are becoming dealers of automobile manufacturers and their direct representatives. The sales center will be concentrated in the Prague region where the parent company has its placr of business. The theoretical part of the thesis is devoted to the characteristics of conventional and alternative fuels. In the practical part there is created a business plan of construction and operation alternative fuel cars showroom. The project is prepared on real numbers and will be used during implementation in practise.
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Aproximación al estudio del riesgo del bleve y sus efectos en los generadores marinos de vapor y los tanques de carga de los buques LNG-LPG. Aplicación comparativa de las normas que lo regulan y previenenMelo Rodríguez, Germán de 04 July 1994 (has links)
BELEVE son las iniciales de la siguiente expresión inglesa "Boiling Liquid Expanding Vapor Explosion" que traducido librementes ignifica "Explosión de los Vapores que se expanden al hervir un líquido".La ELEVE es comúnmente definida como la ruptura en varios pedazos de un recipiente, con proyección a grandes distancias, superiores a las que las desplazarían la simple energía de un estallido, que se da en determinadas circunstancias, siendo necesario, pero no suficiente, que el líquido contenido en el recipiente, posea una temperatura superior a la que le correspondería tener si estuviera a la presión atmosférica normal. Por tanto, la temperatura de ebullición debe ser bastante menor que la temperatura a la que se encuentre la masa líquida en el recipiente, es decir, lo que se llama o denomina líquido sobrecalentado.El fenómeno ELEVE es una manifestación exclusiva de los líquidos sobrecalentados, no debiéndose confundir con las explosiones que se producen en los recipientes que solamente contienen gas, pues las energías desarrolladas por la explosión de este último, no son en absoluto comparables a las elevadas del fenómeno ELEVE.En el caso de que el fenómeno ELEVE se manifieste en un recipiente que contiene líquido que es químicamente reactivo o combustible, agrava el problema de la ELEVE propiamente dicho, ya que anteriormente se ha indicado que un ELEVE se puede producir en una caldera de vapor de agua.Las condiciones necesarias que se han de dar simultáneamente.
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Porovnání parametrů motorů na kapalná a plynná paliva.Červinka, Karel January 2014 (has links)
This thesis introduces and describes a fuel for internal combustion engines. The first part is devoted to a description of the distribution of alternative fuels for road vehicles, pays attention to fuels of biological origin-biofuels. In the second part deals with the problems of exhaust emissions analyze in detail the individual substances and their impact on humans and the environment. The next section describes the vehicle, vehicle test and measuring equipment. Custom work represents the single measurement vehicles Subaru Outback, which is to identify the parameters of the vehicle on two different fuels and their comparison
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Hodnocení paliv pro spalovací motory ve vztahu k životnímu prostředíVančatová, Šárka January 2019 (has links)
The name of this diploma thesis is „Evaluation of combustion engine fuel and its influence on the environment”. At the beginning there is a brief history of fuels. After that there is a chapter which divides fuels according to their state thus they are separate to three main types (solid state, gaseous state and liquid state). There are described main characteristics in the next part of this thesis which are heat of combustion, bulk density, dosage, volatility, resistance to detonation burning and mainly octane and cetane number. There are described currently used fuels for combustion engines right after the characteristic of fuels. These fuels are divided to fuels made of petroleum (gasoline, diesel, and LPG), fuels made of natural gas (CNG, and LNG), biofuels (bioethanol, biomethanol, vegetable oils – FAME and synthetic diesel fuel) and there is also an independent group of hydrogen. Thereafter are described European emission standards. The practical part of the thesis is focused on an analysis of previously mentioned fuels and there is a biggest focus on production of carbon dioxide. Other emissions are evaluated as well such as carbon monoxide, hydrocarbons and NOx gases. The analysis is done on classical fuels like gasoline and diesel and also on alternative fuels such as CNG, LPG, E85, FAME and hydrogen. In the end there are tables and graphs which contains production of flue gases.
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Industrialisering av designkoncept för LPG-mätareAsp, Tobias January 2019 (has links)
Inom bränsleindustrin satsas det på alternativa bränslen. Ett sådant bränsle är gasol(Eng: liquified petroleum gas, LPG). Vid påfyllning av LPG används en bränslepumpoch en av de viktigaste delarna i pumpen är bränslemätaren. På företaget Dover fuelingsolutions finns ett designkoncept för en flödesmätare som företaget vill industrialisera.Syftet är att detta examensarbete ska bidra till vidareutvecklingen av bränslemätare utformadeför att hantera alternativa bränslen som LPG. Målet med examensarbetet äratt konstruera om ett framtaget koncept för en bränslemätare där konceptet utvärderasoch vidareutvecklas med fokus på tillverkning med sandgjutning. Den nya mätarenkonstrueras med datorstödd konstruktion (Eng: Computer-Aided Design, CAD) och medmålet att CAD solider för sandgjutning och bearbetning för prototyptillverkningen skatas fram. Vidare dimensioneras mätarens skruvförband och hållfasthetsberäkningar förmätaren görs med finita elementmetoden. Den omkonstruerade flödesmätaren är konstrueradför att uppfylla kraven för sandgjutning. Flödesmätaren uppfyller dessa krav väl ochär redo för tillverkning. / Within the fuel industry companies currently invest alot in alternative fuels. One suchfuel is liquified petroleum gas (LPG). LPG is filled into vehicles or tanks through a fuelpump. One of the most crucial components in a fuel pump is the fuel meter. At Doverfueling solutions a concept design for a flow meter that can handle LPG and works withpositive displacement has been developed. Through the present work the company wishto further develop and industrialize this concept. This work will contribute to the furtherdevelopment of fuel meters capable of handling alternative fuels such as LPG. In thisthesis a concept is further developed with focus on being able to be manufactured withsand casting. The new meter is constructed with Computer-Aided Design (CAD) andCAD solids for sand casting is developed. The screw joints that holds the flow meterscomponents together is dimensioned. A finite element analysis is made for all of the meterscomponents. The reconstructed flow meter is constructed to satusfy the demands thereare for a component that is going to be sand cast.
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Konstruktion av LPG-bas med separatorenhetAlbayati, Murat, Ahlgren, Sven Erik January 2020 (has links)
Påfyllning av LPG-bränsle (motorgas) till fordon sker i en tankstation och vid tankning är det viktigt att bränslet är filtrerat och i flytande form. Denna filtrering och tillståndsreglering åstadkoms med hjälp av en sammansättning komponenter som kallas LPG-bas. Anledningen till att bränslet måste vara i flytande form är att förångad motorgas tar stort utrymme i fordonstanken i jämförelse med bränslet i flytande form. För att åstadkomma detta behövs en separator. Separatorn är en del av en LPG-bas vars syfte är bland annat att reglera aggregationstillståndet och filtrera bränslet innan det förs vidare till bränslemätaren. På företaget Dover Fueling Solutions finns en befintlig produkt för LPG-bas som företaget vill utveckla. Syftet med arbetet är att modulera och standardisera en ny LPG-bas som ska ersätta den gamla LPG-basen. Den nya LPG-basen moduleras så att den passar in tillsammans med en bas för andra bränslen i den befintliga bränslepumpen. Detta resulterar i en succesiv övergång till motorgasdrivna fordon vilket är rimligt ur ett ekonomiskt perspektiv. Målet med arbetet är att med hjälp av koncept- och detaljutveckling få fram en sammansättning som underlag för framtagning av LPG-basen med önskade dimensioner. I första hand fokuseras det på att LPG-basen passar in i den angivna volymen. Vidare dimensioneras enheterna som ingår i LPG-basen på så sätt att de inte överskrider de givna måtten. Tätning av kopplingar i form av förspänning i skruvförbanden och packningar i form av o-ringar används för att undvika läckage. Vidare analyseras konceptet utifrån hållfasthetsberäkningar och finita elementsimuleringar. Materialval begränsas av företagets kriterier samt krav från PED kriterierna och utförs med fokus på pris. Slutligen presenteras den nya LPG-basen som uppfyller dessa krav väl och är redo för prototypframtagning och testning. / Filling of LPG fuel (Liquefied Petroleum Gas) to vehicles takes place at a filling station and during refueling it is important that the fuel is filtered and in liquid form. This filtration and control of the fuel state is accomplished by means of a group of components called LPG-base. The reason why the fuel must be in liquid form is that evaporated LPG takes up a large amount of space in the vehicle tank compared to the fuel in liquid form. To achieve this, a separator is needed. The separator is part of an LPG-base whose purpose is to, inter alia, regulate the aggregation state and filter the fuel before passing it on to the fuel meter. The company Dover Fueling Solutions has an existing LPG-base product that the company wants to develop. The purpose of the study is to modulate and standardize a new LPG-base that will replace the old LPG-base. The new LPG-base is modulated to fit together with a base for other fuels in the existing fuel pump. This results in a successful transition to LPG-powered vehicles which is reasonable from an economic perspective. The goal of the study is to develop a CAD-model as a basis for developing the LPG-base with the desired dimensions with the help of concept and detail development. In the first place, the focus is on the LPG-base to fit into the specified volume. Furthermore, the units included in the LPG-base are dimensioned in such a way that they do not exceed the given dimensions. Sealing of joints in the form of prestressing in the screw joints and gaskets in the form of O-rings are used to avoid leakage. Furthermore, the concept is analyzed based on strength calculations and finite elementsimulations. Material selection is limited by the company's criteria as well as requirements from the PED criteria and is carried out with a focus on price. Finally, the new LPG-base that meets these requirements is well presented and is ready for prototype development and testing.
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Numerical Analysis of Optically-induced Long-period Fiber Gratings for Sensing ApplicationsWang, Chaofan 25 September 2014 (has links)
Long-period fiber gratings (LPGs) with a period ranging from several hundred micrometers to a few millimeters can couple a core mode to discrete co-propagating cladding modes when the phase matching condition is satisfied. The rapid attenuation of cladding modes results in loss bands in the transmission spectrum. As the attenuation bands are sensitive to the LPG period and the fiber surrounding environment such as temperature, strain and ambient refractive index, LPGs can be used for sensing. However, traditional LPGs with gratings inscribed in the fibers can only sense a single point and cannot be used for distributed sensing. Although new ideas were proposed to use traveling LPG formed by a pulsed acoustic wave, the large attenuation of the acoustic wave in the fiber greatly limits the sensing range to only several meters.
In this thesis, we proposed to use a traveling LPG formed by the interference of two high power co-propagating core modes, usually LP01 and LP11. The beating of the two modes will induce a refractive index grating due to the optical Kerr effect, and the grating is called optically induced long-period fiber grating (OLPG). Compared to the grating induced by acoustic waves, OLPG is able to travel for a long distance due to the small attenuation of the guided core modes. Mode conversion in the OLPG is numerically simulated and analyzed using the finite-difference beam propagation method (FD-BPM). The result shows full conversion for both core-core and core-cladding mode coupling under phase matching condition. Moreover, the sensitivity of OLPG to temperature, axial strain and ambient refractive index is investigated and analyzed. It is seen that the sensitivities of temperature and axial strain with OLPG are different from the traditional LPGs since the period variation in OLPG is caused by the effective index difference of the two core modes at the writing wavelength, while in the traditional LPGs it is directly induced by temperature or strain. For the refractive index sensitivity with a large cladding, OLPG behaves the same as a traditional LPG with only material contributions since the grating period remains unchanged. / Master of Science
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