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High-pressure experiments and chemical kinetics modeling were performed for laminar spherically expanding flames for methane/air, ethane/air, methane/ethane/air and propane/air mixtures at pressures between 1 and 10 atm and equivalence ratios ranging from 0.7 to 1.3. All experiments were performed in a new flame speed facility capable of withstanding initial pressures up to 15 atm. The facility consists of a cylindrical pressure vessel rated up to 2200 psi. Vacuums down to 30 mTorr were produced before each experiment, and mixtures were created using the partial pressure method. Ignition was obtained by an automotive coil and a constant current power supply capable of reducing the spark energy close to the minimum ignition energy. Optical cine-photography was provided via a Z-type schlieren set up and a high-speed camera (2000 fps). A full description of the facility is given including a pressure rating and a computational conjugate heat transfer analysis predicting temperature rises at the walls. Additionally, a detailed uncertainty analysis revealed total uncertainty in measured flame speed of approximately +-0.7 cm/s. This study includes first-ever measurements of methane/ethane flame speeds at elevated pressures as well as unique high pressure ethane flame speed measurements. Three chemical kinetic models were used and compared against measured flame velocities. GRI 3.0 performed remarkably well even for high-pressure ethane flames. The C5 mechanism performed acceptably at low pressure conditions and under-predicted the experimental data at elevated pressures. Measured Markstein lengths of atmospheric methane/air flames were compared against values found in the literature. In this study, Markstein lengths increased for methane/air flames from fuel lean to fuel rich. A reverse trend was observed for ethane/air mixtures with the Markstein length decreasing from fuel lean to fuel rich conditions. Flame cellularity was observed for mixtures at elevated pressures. For both methane and ethane, hydrodynamic instabilities dominated at stoichiometric conditions. Flame acceleration was clearly visible and used to determine the onset of cellular instabilities. The onset of flame acceleration for each high-pressure experiment was recorded.

Eine kompakte und effiziente Wasserstofferzeugung aus verfügbaren Energieträgern ist für die Marktfähigkeit von Brennstoffzellenheizgeräten essentiell. Der Auslegung von Reformern für PEM-Brennstoffzellen kommt eine große Bedeutung zu, da bei diesem Brennstoffzellentyp keine interne Reformierung möglich ist. In dieser Arbeit werden die mathematische Modellierung der Dampfreformierung von Erdgas, die Rolle der eingesetzten Katalysatoren und die Problematik von Wärme- und Stofftransportprozessen untersucht. Für fünf kommerzielle Nickel- und einen Rhodiumkatalysator werden die Kinetik, die effektive Wärmeleitfähigkeit und der Diffusionskoeffizient ermittelt. Unter Verwendung dieser Werte wird in einem Einzelpartikelmodell die Existenz und Signifikanz von intra- und extrapartikulären Stoff- und Temperaturgradienten evaluiert. Daraus werden für ein quasihomogenes Reaktormodell Modellparameter abgeleitet, die eine exakte Simulation unter Berücksichtigung der relevanten Phänomene zulassen. Schließlich wird ein Reaktormodell erstellt, welches mit Messwerten aus einem Versuchsreaktor validiert und für eine Sensitivitätsanalyse verwendet wird.

Renewable Natural Gas (RNG) is a low-carbon fuel source that is derived from the anaerobic digestion (AD) or thermal gasification (TG) of biomass, or produced using renewable electricity through the methanation of carbon dioxide. This thesis uses a thermodynamic balance to determine the total technical potential of RNG in the United States, as well as the future technical potential of methanation-derived RNG based on growth curves for renewable electricity. Furthermore, this work establishes an analytic decision-making framework for determining on a rolling basis, from an economic standpoint, whether to sell electricity directly to the grid, or produce and sell methanation-derived RNG. This framework is used to establish the economic potential of RNG, based on Texas wind resources. This work details the formulation of a model that determines which production option generates more marginal profit, based on fluctuating electricity and gas prices. The model also aggregates the total amount of electricity and RNG sold, assuming that the main objective is to maximize the marginal profit of integrated wind- and methanation facilities. This work concludes that the annual technical potential of methanation-derived RNG nationally was 1.03 Quads in 2011. The technical potential of biomass-derived RNG was 9.5 Quads. Thus, the total 2011 technical potential of RNG in the United States was 10.5 Quads, or equal to roughly 43% of the total US consumption of natural gas that year. Assuming a constant, 80% electrolyser efficiency, the technical potential of methanation-derived RNG is expected to rise at an average rate of 1.4% per year, following growth curves for renewable power, until the year 2040, when it will be 1.54 Quads. The 2011 economic potential of methanation-derived RNG in Texas was between 2.06×10⁷ MMBTU and 3.19×10⁷ MMBTU, or between 19.4% and 30.1% of the corresponding annual technical potential. Furthermore, the total marginal profit increase from introducing the option of producing and selling methanation-derived RNG was around $366 million, given a ‘best case scenario’ for the state of Texas. / text

This Master’s thesis seeks to develop a better understanding of how Indigenous voices can be included in water governance. As a starting point, social learning theory, collaborative governance and Indigenous and Canadian relations were carefully studied. Despite the large body of research on collaborative governance with First Nations and on social learning in water governance, little is known specifically about social learning processes in colonial contexts. Using grounded theory and Indigenous methodologies, this research investigates how the current approach to implementing the Province’s legal constitutional, “duty to consult” affects social learning processes and the inclusion of Indigenous people in water governance. Findings indicate that the laws and policies that have been created based on the Crown’s interpretation of Treaty 8, an agreement signed between the Fort Nelson First Nation and Canada in 1899. This duty to consult constrains social learning, as it does not allow for the flexibility needed for a reframing process that might bring the actors to a common understanding of Treaty 8, the treaty relationship and its application as such today, as a basis for future collaboration. Without reframing processes, the consultation process is perceived by the Fort Nelson First Nation, a Treaty 8 nation, to lack legitimacy and neutral facilitation. Subsequently, consultation is seen as a checkbox that must be completed, but fails to include First Nations’ knowledge, interests and concerns about impacts from development and appropriate accommodation. This research also investigates a new governance arrangement emerging in northeast BC, which changes the way Fort Nelson First Nation voices are included in decision-making. Processes of nation building and capacity building contribute to Fort Nelson First Nation’s New Approach to governance. The New Approach sees changes to the sites of authority, revenue and norms and beliefs, resulting in a governance innovation that circumvents the provincial government’s role in governance by creating a closer working relationship between industry and the Fort Nelson First Nation. The results are development planning and decisions that better reflect the Fort Nelson First Nation’s concerns and interests in the near future. / Graduate

This report offers a comparative valuation of two bitumen production technologies, using real options analysis (ROA) techniques to incorporate strategic flexibility into the investment scenario. By integrating a probabilistic cost model into a real options framework, the value of an oil recovery facility is modeled to reflect the realistic alternatives available to decision-makers, where the course of the investment can be altered as new information becomes available. This approach represents a distinct advantage to traditional discounted cash flow (DCF) estimation, which is unable to capture operational adaptability, including the ability to expand, delay, or abandon a project. The analysis focuses on the energy inputs required for the recovery of heavy oil bitumen from Alberta, Canada, and examines both natural gas and nuclear steam plants as heat sources. The ACR-1000 reactor is highlighted as a substitute for conventional natural gas-fueled means of production, in light of the recent volatility of natural gas prices and the potential for emissions compliance charges. The methodology includes a levelized cost assessment per barrel of bitumen and estimation of cost ranges for each component. A mean-reversion stochastic price model was also derived for the both natural gas and oil price. By incorporating cost ranges into a ROA framework, the benefit of retaining project flexibility is included in its valuation. Formulated as a decision tree, built-in options include the initial selection to pursue nuclear or natural gas, site selection and licensing, the ability to switch heat source in the planning stage, and the final commitment to construct. Each decision is influenced by uncertainties, including the course of bitumen and natural gas price, as well as emissions policy. By structuring the investment scenario to include these options, the overall value of the project increases by over $150 million. The ability to switch technology type allows for an assessment of the viability of nuclear steam, which becomes economically favorable given high natural gas prices or high emissions taxes. Given an initial selection of natural gas SAGD, there is a 25% probability that a switch to nuclear steam will occur, as evolving financial conditions make nuclear the optimal technology. / text

Η μετατροπή του φυσικού αερίου προς αέριο σύνθεσης αποτελεί εξαιρετικά σημαντική διεργασία αφού το αέριο σύνθεσης είναι απαραίτητο για την παραγωγή μεθανόλης και τη σύνθεση Fischer-Tropsch. Η ευρύτερα διαδεδομένη διεργασία για τη μετατροπή του μεθανίου – το οποίο αποτελεί το κυριότερο συστατικό του φυσικού αερίου - προς αέριο σύνθεσης είναι η αναμόρφωσή του με ατμό. Τα τελευταία χρόνια όμως ερευνήθηκαν κι άλλες μέθοδοι παραγωγής αερίου σύνθεσης από μεθάνιο όπως η αναμόρφωση με CO2, η καταλυτική και μη μερική οξείδωση του μεθανίου κ.ά. Μεταξύ των διεργασιών που προαναφέρθηκαν η καταλυτική μερική οξείδωση του μεθανίου προς αέριο σύνθεσης κερδίζει έδαφος σε ερευνητικό επίπεδο. Η διεργασία παρουσιάζει σημαντικά πλεονεκτήματα όπως το γεγονός ότι δεν είναι τόσο ισχυρά εξώθερμη όσο η καύση του μεθανίου προς CO2 και Η2, καθώς και το γεγονός ότι η αναλογία του παραγόμενου αερίου σύνθεσης είναι CO/H2 : ½ αναλογία που είναι η απαραίτητη για την παραγωγή μεθανόλης και τη σύνθεση Fischer-Tropsch. Η μερική οξείδωση του μεθανίου προς αέριο σύνθεσης έχει μελετηθεί εκτενώς σε αντιδραστήρες σταθερής κλίνης. Λόγω όμως των μειονεκτημάτων που παρουσιάζουν κυριότερα από τα οποία είναι η ανάπτυξη θερμών κηλίδων λόγω της εξώθερμης καύσης που λαμβάνει χώρα στην καταλυτική κλίνη και η υψηλή πτώση πίεσης, η έρευνα στράφηκε στην αναζήτηση νέου τύπου αντιδραστήρων. Στην παρούσα εργασία η μερική οξείδωση του μεθανίου προς αέριο σύνθεσης μελετήθηκε σε αντιδραστήρα τοιχώματος θερμικής ολοκλήρωσης και σε μονολιθικό αντιδραστήρα. Ο αντιδραστήρας τοιχώματος θερμικής ολοκλήρωσης αποτελείται από ένα κεραμικό μη πορώδη σωλήνα υψηλής θερμικής αγωγιμότητας στον οποίο εναποτίθεται καταλύτης σε μορφή συνεχούς φιλμ. Ο αντιδραστήρας εσωκλείεται σε ένα δεύτερο σωλήνα που μπορεί να είναι από κεραμικό ή χαλαζία. Λόγω της κατασκευής του αντιδραστήρα υπάρχει δυνατότητα εναπόθεσης του καταλύτη στο εσωτερικό και στο εξωτερικό τοίχωμα του κεραμικού σωλήνα. Ο καταλύτης που χρησιμοποιήθηκε ήταν Rh/Al2O3. Μελετήθηκε η επίδραση του τρόπου εναπόθεσης του καταλύτη, η μεταβολή της παροχής εισόδου, η μεταβολή της θερμοκρασίας του φούρνου και η επίδραση της ποσότητας του καταλύτη που εναποτίθεται στον αντιδραστήρα. Τα αποτελέσματα έδειξαν ότι η εναπόθεση κατάλληλης ποσότητας καταλύτη στην εξωτερική και εσωτερική επιφάνεια του αντιδραστήρα μπορεί να οδηγήσει σε ομοιόμορφο θερμοκρασιακό προφίλ κατά μήκος του αντιδραστήρα αφού η θερμότητα που παράγεται στην εσωτερική επιφάνεια του αντιδραστήρα κατά την εξώθερμη καύση, μεταφέρεται μέσω του τοιχώματος στην εξωτερική επιφάνεια όπου πραγματοποιούνται οι ενδόθερμές αντιδράσεις αναμόρφωσης. Η απουσία θερμών κηλίδων δίνει τη δυνατότητα χρήσης υψηλών παροχών εισόδου. Από τα πειραματικά αποτελέσματα υπήρχαν ενδείξεις ότι μέρος του παραγόμενου CO παράγεται μέσω του άμεσου σχήματος. Η μερική οξείδωση του μεθανίου προς αέριο σύνθεσης μελετήθηκε και σε μονολιθικό αντιδραστήρα. Το κυριότερο πλεονέκτημα των μονολιθικών αντιδραστήρων είναι η χαμηλή πτώση πίεσης και η μεγάλη ενεργός επιφάνεια. Ο καταλύτης που εναποτέθηκε στο εσωτερικό των καναλιών του μονόλιθου ήταν 0.5% Ru/TiO2 (2%CaO) ο οποίος είναι ενεργός και σταθερός για την μερική οξείδωση του μεθανίου προς αέριο σύνθεσης. Στα πειράματα που πραγματοποιήθηκαν σε μονολιθικό αντιδραστήρα μελετήθηκε η επίδραση της μεταβολής της παροχής, της μεταβολής της θερμοκρασίας του φούρνου, καθώς και η σύσταση του μίγματος εισόδου. Τα πειραματικά αποτελέσματα έδειξαν ότι αρχικά λαμβάνει χώρα η εξώθερμη καύση του μεθανίου προς CO2 και Η2Ο και ακολουθούν οι αντιδράσεις αναμόρφωσης. Η καύση του μεθανίου ευνοείται σε χαμηλή θερμοκρασία ενώ οι αντιδράσεις αναμόρφωσης ευνοούνται σε υψηλή θερμοκρασία φούρνου. Η μετατροπή μεθανίου και η εκλεκτικότητα προς αέριο σύνθεσης επηρεάζονται τόσο από τη παροχή εισόδου όσο και από τη θερμοκρασία του φούρνου. Σημαντικό παράγοντα για τη διατήρηση της σταθερότητας του καταλύτη αποτελεί το μέγεθος των κόκκων του καταλύτη η διάμετρος των οποίων πρέπει να είναι d<0.09mm. Προκειμένου να γίνει πρόβλεψη των φαινομένων που λαμβάνουν χώρα σε ένα μονολιθικό αντιδραστήρα καταστρώθηκε μοντέλο το οποίο προσομοίαζε το μονολιθικό αντιδραστήρα κατά τη διάρκεια της αντίδρασης. Θεωρήθηκε ότι ο καταλύτης που έχει εναποτεθεί στο μονόλιθο ήταν 0.5% Ru/TiO2 (2%CaO). Μελετήθηκε η επίδραση της αρχικής θερμοκρασίας, της αρχικής πίεσης, της σύστασης και της παροχής εισόδου. Τα αποτελέσματα έδειξαν ότι μπορεί να προβλεφθεί ποιοτικά η ανάπτυξη του θερμοκρασιακού προφίλ κατά μήκος του μονόλιθου, καθώς και οι τιμές της μετατροπής μεθανίου και της εκλεκτικότητας προς CO και Η2. Η παράλειψη κάποιων παραδοχών ώστε να προσεγγίζονται καλύτερα οι πραγματικές συνθήκες λειτουργίας του αντιδραστήρα θα οδηγούσε στην προσέγγιση των πειραματικών αποτελεσμάτων με εκείνα που προβλέπονται από τους υπολογισμούς όχι μόνο ποιοτικά αλλά και ποσοτικά. / The conversion of natural gas to synthesis gas is a very important process because synthesis gas is necessary for the Fischer-Tropsch synthesis and also for the production of methanol. The most common process for producing synthesis gas from natural gas is the steam reforming of methane, since methane is the main component of natural gas. Recently, a significant amount of effort has been directed to processes alternative to steam reforming of methane such as CO2 reforming, catalytic and not catalytic partial oxidation of methane, e.t.c. Among the above mentioned processes partial oxidation of methane seems to be the most attractive alternative to steam reforming of methane for converting natural gas to synthesis gas, owing to a number of advantages. The most important among them are, the small amount of heat that is produced during the reaction compared to the heat that is produced during the combustion of methane to CO2 and H2O, and the ratio of the produced synthesis gas which is CO/H2 : ½ which is exactly the necessary ratio for the Fischer Tropsch and methanol synthesis. The catalytic partial oxidation of methane to synthesis gas has been studied using fixed bed reactors, mainly. Due το the disadvantages of this kind of reactors such as the development of hot spots during the combustion of methane and the high pressure drop, the study of partial oxidation of methane has been made in other kind of reactors such as fluidized bed reactors, honeycomb reactors, auto-thermal reactors, e.t.c. In the present study the catalytic partial oxidation of methane has been studied in a Heat Integrated Wall Reactor (HIWAR) and also in a monolithic reactor. The Heat Integrated Wall Reactor consists of a non-porous ceramic tube of high thermal conductivity in the inner and outer surface of which the catalytic film is deposited. The tube is enclosed in another tube, which can be ceramic or quartz. Because of the way of construction of the reactor the catalyst that is deposited in the inner surface of the ceramic tube can be different from the one that is deposited on the outer surface of the tube. The catalyst that was used for the study of the partial oxidation to synthesis gas in the Heat Integrated Wall Reactor was Rh/Al2O3. The factors the influence of which was studied here were the type of deposition of the catalyst film on the tube, the furnace temperature, the flow rate and the amount of catalyst that was deposited in the inner and outer surface of the tube. The experimental results indicated that there is an optimum amount of catalyst that can be deposited on the inner and outer surface of the reactor in order to obtain a flat temperature profile without the development of hot spots. The range of flow rates that can be used in the HIWAR is bigger than the range that can be used in a conventional reactor, due to the absence of hot spots. Some experimental results also indicated that part of CO is produced via the direct scheme. Partial oxidation of methane to synthesis gas had been studied in a monolithic reactor as well. The main advantages of monolithic reactors are the very low pressure drop and the high surface area. The catalyst that was used during this study was 0.5% Ru/TiO2 (1%CaO), which is a very active and stable catalyst for this reaction. During the experiments that took place in the monolithic reactor the factors the influence of which was studied here were the flow rate, the furnace temperature and the feed composition. The experimental results indicated that the combustion of methane takes place initially which is followed by the endothermic reforming reactions. The combustion of methane to CO2 and H2O is favored in low temperatures while the endothermic reforming reaction is favored in high temperatures. Methane conversion as well as CO and H2 selectivity change as the flow rate and furnace temperatures change. Experimental results indicated that a catalyst grain diameter less than 0,09 mm is necessary for the catalyst to be stable during the reaction. In order to predict the behavior of factors such as temperature, methane conversion and CO and H2 selectivity during the catalytic partial oxidation of methane in a monolithic reactor, a one-dimensional model was developed in order to simulate the monolithic reactor during the reaction. The calculations were based on the rate equations that were developed using experimental results for the 0,5%Ru/TiO2 (1% CaO). The influence of the initial temperature, initial pressure, flow rate and feed composition were studied. Comparison of the results of the simulations against those of the experimental studies indicated that calculations qualitatively predict the behavior of the reactor but not quantitatively, probably due to the assumptions that were introduced during the development of the model, i.e. one dimensionality of the model, uncertainties in the rate expressions etc. Relaxing some of those assumptions in order to approach the real operating conditions of the reactor is expected to enhance quantitative agreement between the experimental and numerical results.

Milind Kandlikar is uncovering how Delhi’s air quality problem isn’t necessarily a traffic congestion problem.

Unless subjected to skeptical and conscious scrutiny, environmentally-friendly ocean energy technologies can become “Trojan machines of social inequity” due to the subtle re-organizing influences of technologies on culture and the society. Environmental laws that promote or regulate ocean energy technologies can act as “Trojan legal regimes” in the absence of a framework for assessing and anticipating their adverse impacts on social justice. “Environmental justice” is inadequate for this task, so an alternative framework is proposed: ecological social justice, drawn from the Third World’s perspective of sustainable development as equitable sharing. Though overshadowed by the prevalent notion of sustainable development as limits to growth, a review of international environmental law shows that the ideas of equitable sharing have persisted, underpinning demands for more equitable distribution of resources and environmental amenities, greater public participation in decision-making, and special attention in favor of specified social groups. Beginning with the critiques of environmental justice and then drawing upon a substantivist view of the role of the Economy as an ecological link between Society and Nature, a sketch of ecological social justice is drawn. The assessment of whether specific legal regimes or their implementation promote or hinder social justice revolve around three focal points: distribution, recognition, and participation, and pay special attention to the role of culture and power in society. The assessment also incorporates and emphasizes the ‘local’ conception of social justice in order to remain true to its ‘ecological’ character. To demonstrate, the paper conducts detailed case studies of the Philippines. The 1987 Constitution established a right to environment as a result of the historical evolution of a constitutional policy of promoting social justice, This caused Philippine environmental and ocean resource laws to incorporate provisions that promote ecological social justice. Analysis of Philippine ocean environment and energy laws and two internationally-recognized ocean energy projects reveals insights into how even the most environmentally-friendly but complex technologies can lead to domination and oppression, and how guiding ideals of equitable sharing at the local levels can lead to more socially-just solutions.

A CO2 emission analysis and system investigation of a direct fuel cell waste energy recovery and power generation system (DFC-ERG) for pressure letdown stations was undertaken. The hybrid system developed by FuelCell Energy Inc. is an integrated turboexpander and a direct internal reforming molten carbonate fuel cell system in a combined circle. At pressure letdown stations, popularly called city gates, the pressure of natural gas transported on long pipelines is reduced by traditional pressure regulating systems. Energy is lost as a result of pressure reduction. Pressure reduction also results in severe cooling of the gas due to the Joule Thompson effect, thus, requiring preheating of the natural gas using traditional gas fired-burners. The thermal energy generated results in the emission of green house gases. The DFC-ERG system is a novel waste energy recovery and green house gas mitigation system that can replace traditional pressure regulating systems on city gates. A DFC-ERG system has been simulated using UniSim Design process simulation software. A case study using data from Utilities Kingston’s city gate at Glenburnie was analysed. The waste energy recovery system was modelled using the design specifications of the FuelCell Energy Inc’s DFC 300 system and turboexpander design characteristics of Cryostar TG120. The Fuel Cell system sizing was based on the required thermal output, electrical power output, available configuration and cost. The predicted performance of the fuel cell system was simulated at a current density of 140mA/cm2, steam to carbon ratio of 3, fuel utilization of 75% and oxygen utilization of 30%. The power output of the turboexpander was found to strongly depend on the high pressure natural gas flowrate, temperature and pressure. The simulated DFC-ERG system was found to reduce CO2 emissions when the electrical power generated by the DFC-ERG system replaced electrical power generated by a coal fired plant. / Thesis (Master, Chemical Engineering) -- Queen's University, 2010-08-31 02:02:11.392