In pellet production, the parameters, such as densification pressure, temperature, feed moisture content, and coal and biomass concentration, that affected pelletizing and pellet quality were investigated. Gasification was carried out in a downdraft gasifier by using red oak hard wood as the feedstock. The raw syngas primarily contained carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), methane (CH4), and nitrogen (N2) as well as contaminants such as ash, water vapor, ammonia, and oxygen. Ash was removed with the filter bag. Water vapor was removed by desiccant absorption. Ammonia was removed by water scrubbing. Oxygen was removed by a CuO/CeO2-Al2O3 catalyst in a fixed-bed tubular reactor from 1% to less than 1ppm. After cleaning, the syngas was compressed up to 2000 psig pressure. The clean syngas was readily used for the Fischer-Tropsch catalytic reaction.

Στόχος της παρούσας εργασίας είναι η ανάπτυξη ενός μεθοδολογικού σχήματος που συνίσταται από τον CLEAN αλγόριθμο, και την παραγοντική ανάλυση, για τη μελετη χρονοσειρων παραμετρων βιολογικου καθαρισμου βιομηχανιας. Ο CLEAN αλγόριθμος χρησιμοποιείται για την πλήρωση κενών στα αρχικά δεδομένα ώστε να προκύψουν συνεχείς χρονοσειρές, ενώ η παραγοντική ανάλυση ανιχνεύει τις σχέσεις μεταξύ των αρχικών μεταβλητών. Η ανάπλαση των χρονοσειρών αναδεικνύει τις σημαντικότερες πληροφορίες όσον αφορά τη χρονική διακύμανση των κυρίαρχων διεργασιών του βιολογικού καθαρισμού – τα αποτελέσματα ενισχύονται με την εφαρμογή της παραγοντικής ανάλυσης. Η παρούσα εργασία προτείνει ένα σχετικά απλό και αποτελεσματικό μεθοδολογικό σχήμα για τη καλύτερη παρακολούθηση της λειτουργίας μονάδων βιολογικού καθαρισμού. Αναλύθηκαν και μελετήθηκαν δεκατρείς παράμετροι, οι οποίες συλλέχθηκαν σε περίοδο οχτώ ετών. Με την εφαρμογή της CLEAN φασματικής ανάλυσης και της παραγοντικής ανάλυσης επεξεργάστηκαν συνολικά 37.960 δεδομένα. Αρχικά, ο CLEAN αλγόριθμος λειτούργησε με μεγάλη επιτυχία και συμπλήρωσε όλα τα κενά των αρχικών ανεπεξέργαστων δεδομένων και στη συνέχεια με την εφαρμογή της παραγοντικής ανάλυσης φάνηκε ότι επτά διεργασίες ελέγχουν διαχρονικά τη λειτουργία του βιολογικού καθαρισμού. Η CLEAN φασματική ανάλυση σε συνδυασμό με την πολυδιάστατη στατιστική παραγοντική ανάλυση αποτελούν ένα αποτελεσματικό και εξαιρετικά χρήσιμο εργαλείο για την μελέτη περιβαλλοντικών δεδομένων. / The scope of the study is the development of a methodology based on CLEAN algorithm and factor analysis for the study of the time series of parameters from a waste water treatment unit. CLEAN algorithm is used to cover missing data and measurements in order to create a time series without gaps, while factor analysis is used to detect relations and connection between the different parameters. Filling in the gaps in the time series, points out the most important information about frequency and repeatability of the basic procedures in the waste water treatment – those results are further supported by application of the factor analysis. This study suggests a simple and efficient approach for the supervision of waste water treatment units. Thirteen parameters, recorded for an eight years period were analyzed using the suggested methodology. 37.960 data in total were analyzed and processed. CLEAN algorithm was successfully applied to fill the gaps in the data. Factor analysis was used to point out 7 procedures as the key – factors controlling the waste water treatment operation for the whole time period. CLEAN algorithm in combination with the multiparameter statistical factor analysis compose a useful and effective tool for the study of complex environmental systems, like waste water units.

No description available.

The Kyoto Protocol allows for the development of an international emissions-trading system. This led to the formulation of various mechanisms, namely Joint Implementation (JI), the Clean Development Mechanism (CDM) and Emissionstrading (ET). Given the potential emission-reduction targets in 2012 for developing countries, and in particular for South Africa, the objective of this study is identifying the current implementation of the CDM project cycle steps, as well as assessing the appropriateness of them. Constraints, bottlenecks and opportunities, are identified and suggestions for improvement are made, in order to improve the body of scientific knowledge. From the literature survey, and from discussions with experts in the field, it appears as if the benefits and issues identified, corroborate international findings. Benefits for countries hosting CDM projects include improved balance of payment, technology transfer and replacement of inefficient technology. Commonly occurring concerns, are that baseline setting, additionality and the entire CDM project cycle is complex. Resource and time constraints could jeopardize projects. Transaction costs have been prohibitive, further compounded by lack of initial upfront funding. Bureaucracy from the CDM executive board has frustrated attempts to implement projects. Lack of methodologies, as well as huge risk and cost in developing new methodologies have been obstacles for project developers, while clear guidelines on monitoring, governance and additionality have been conspicuously absent. Suggestions for improvement have been regular baseline revision and standard assessment procedures, application of the gold standard and an additionality tool. Issues that seem to be uniquely particular to South Africa are the slow adoption of large companies to accept the benefits of CDM, difficulty in convincing company executives to embark on CDM projects, as well as unwillingness to delegate authority to technical staff. Another notable pattern is a mismatch of opinion between scientists, academics and business. South Africa uniquely, produces 90% of its energy from fossil fuels, which could limit the adoption of CDM. Lack of institutional knowledge and experience is concerning, as well as ethics and little collaboration amongst stakeholders. Innovative suggestions for improvement have included a weighting for sustainable development indicators, benchmarks to simplify baselines, sink projects to be excluded owing to their risk, sellers clearing houses, industrial gases to be excluded, and programmatic CDM. Another important suggestion is that taxation of CDM credits should be abandoned, and the restrictive Public Finance Management Act to be improved. The proposed study has attempted to highlight some of these significant issues, with the view to improving the current knowledge and advance the possibility of alleviating some of these burdening issues.

Non-thermal plasmas are considered to be very promising for the initiation of chemical reactions and a vast amount of experimental work has been dedicated to plasma assisted hydrocarbon conversion processes, which are reviewed in the fourth chapter of the thesis. However, current knowledge and experimental data available in the literature on plasma assisted liquid hydrocarbon cracking and gaseous hydrocarbon decomposition is very limited. The experimental methodology is introduced in the chapter that follows the literature review. It includes the scope and objectives section reflecting the information presented in the literature review and the rationale of this work. This is followed by a thorough description of the design and construction of the experimental plasma reformer and the precise experimental procedures, the set-up of hydrocarbon characterization equipment and the development of analytical methods. The methodology of uncertainty analysis is also described. In this work we performed experiments in attempt the cracking of liquid hexadecane into smaller liquid hydrocarbons, which was not successful. The conditions tested and the problems encountered are described in detail. In this project we performed a parametric study for methane and propane decomposition under a corona discharge for COx free hydrogen generation. For methane and propane a series of experiments were performed for a positive corona discharge at a fixed inter-electrode distance (15 mm) to study the effects of discharge power (range of 14 - 20 W and 19 – 35 W respectively) and residence time (60 - 240 s and 60 – 303 s respectively). A second series of experiments studied the effect of inter-electrode distance on hydrogen production, with distances of 15, 20, 25, 30 and 35 mm tested. The analysis of the results shows that both discharge power and residence time, have a positive influence on gaseous hydrocarbon conversion, hydrogen selectivity and energy conversion efficiency for methane and propane decomposition. Longer discharge gaps favour hydrogen production for methane and propane decomposition. A final series of experiments on corona polarity showed that a positive discharge was preferable for methane decomposition.

No description available.

Let R be a ring. We say x ∈ R is clean if x = e + u where u is a unit and e is an idempotent (e2 = e). R is clean if every element of R is clean. I will give the motivation for clean rings, which comes from Fitting's Lemma for Vector Spaces. This leads into the ABCD lemma, which is the foundation of a paper by Camillo, Khurana, Lam, Nicholson and Zhou. Semi-perfect rings are a well known type of ring. I will show a relationship that occurs between clean rings and semi-perfect rings which will allow me to utilize what is known already about semi-perfect rings. It is also important to note that I will be using the Fundamental Theorem of Torsion-free Modules over Principal Ideal Domains to work with finite dimensional vector spaces. These finite dimensional vector spaces are in fact strongly clean, which simply means they are clean and the idempotent and unit commute. This additionally means that since L = e + u, Le = eL. Several types of rings are clean, including a weaker version of commutative Von Neumann regular rings, Duo Von Neumann regular, which I have proved. The goal of my research is to find out how many ways to write matrices or other ring elements as sums of units and idempotents. To do this, I have come up with a method that is self contained, drawing from but not requiring the entire literature of Nicholson. We also examine sets other than idempotents such as upper-triangular and row reduced and examine the possibility or exclusion that an element may be represented as the sum of a upper-triangular (resp. row reduced) element and a unit. These and other element properties highlight some of the complexity of examining an additive property when the underlying properties are multiplicative.

<p>Lean refers to the concepts of Lean operations, Lean principle, Lean philosophy, etc. It is what people often talk about in operation management. Clean refers to the concepts of being green, environmental friendly, less environmental impact, etc. These two words seem to be unrelated, but somehow connected.</p><p>In this thesis, we explored the linking between Lean and environmental issues; analyze the possible benefits of coordination between Lean and environment. In the case study, we assessed the overall Lean performance of Alderholmens mekaniska, a local manufacturing company in Gävle, Sweden. This company was seeking for solutions of their environmental wastes in the production.</p><p>We found that Lean activities could be used to achieve environmental objectives. Lean methods are capable of reducing environmental waste. To coordinate Lean and environmental issues could foster an organizational culture of continuous improvement in order to encourage people to improve for better overall performance; this also benefits the environmental performance.</p><p>Based on the observation in the company, and the questionnaire made during an interview with their Lean specialist, we gave some proposals on Lean implementation with emphasis on environmental issues, in order to solve their problems of environmental wastes and, furthermore, improve the performance.</p>

No description available.

One of the main challenges that investors in the Clean Development Mechanism (CDM) project face is the management of the volatility of the price of Certified Emission Reduction (CERs). Large scale CDM projects require a long-term investment with significant amount of costs, and this type of investment is often irreversible. Project investors should quantitatively assess the CER trigger price that justifies the initiation of a CDM investment. The traditional discounted cash flow valuation is unable to capture the option value associated with uncertain investment, and thus it tends to underestimate the trigger price which initiates the investment. Real options theory explicitly considers the option value of delayed investment and can provide a better measurement of the trigger price. This paper presents a theoretical model of the CDM investment project and derives the CER trigger prices that guide investment decisions by using historical market data. It develops a stochastic dynamic programming model for both the geometric Brownian motion process and the mean-reverting process. An analytical solution for the trigger price is derived for the former process, and the trigger price is numerically estimated for the latter. By considering various parameter values, it analyzes the effects of different market environments on the trigger price.