No abstract

The product distribution for the Fischer-Tropsch synthesis is normally described using the kinetically derived (Anderson-Schultz-Flory) ASF model. Variations of the kinetic model have been proposed to explain deviations from the ASF distribution. The Fischer-Tropsch system can be equally well described using a pseudo-element (CH 2 , H 2 , O) equilibrium approach. A one-parameter equilibrium model is derived for the product distributions for alkenes, alkanes and alcohols.The Fischer-Tropsch system should be considered as three separate partial equilibria systems: the product homologous series; the water gas shift system, and the redox behaviour of the catalyst with the H 2 /O ratio of the gas. This approach correctly predicts the impacts of changes in a variety of parameters (temperature pressure, feed composition) on the ASF product distribution. In addition, the catalyst phase changes with gas composition and pressure, indicative of an equilibrium response. Equilibrium is of much greater importance to the Fischer-Tropsch system than previously thought, and the decision to use a complex kinetics-based model rather than a simpler equilibrium based model should be taken with care.La distribution de produits dans la synthèse Fischer-Tropsch est normalement décrite par le modèle ASF (Anderson-Schultz-Flory)établi par la cinétique. Des variations du modèle cinétique sont proposées pour expliquer lesécarts par rapportà la distribution de l'ASF. Le système FischerTropsch peutêtre aussi bien décrit par la méthode deséquilibres de pseudo-éléments (CH 2 , H 2 , O). Un modèle d'équilibreà un paramètre est etabli pour la distribution des alcènes, alcanes et alcools. Le système Fischer-Tropsch devraitêtre considéré comme 3 systèmes d'équilibres partiels séparés: la série homologue de produits, le système de conversion eau-gaz et le comportement redox du catalyseur avec le rapport H 2 :O du gaz. Cette approche prédit correctement l'impact des changements sur plusieurs paramètres (température, pression, composition de l'alimentation) sur la distribution de produits de l'ASF. En outre, la phase du catalyseur change avec la composition du gaz et la pression, indiquant une réactioǹ a l'équilibre. L'équilibre est d'une importance beaucoup plus grande pour le modèle Fischer-Tropsch que ce qu'on pensait, et la décision d'utiliser un modèle complexe basé sur la cinétique plutôt que basé sur deséquilibres plus simple devraitêtre soigneusement pesée.

A method is presented for identifying a subset of species (from a set of reacting species) that are within a specified numerical tolerance of equilibrium, as implied by a given experimental composition. The method also determines a linearly independent set of reactions involving these species and the number of stoichiometric restrictions inherent in the set. This is an aid in reactor modeling, for example, in the computation of concentration profiles, in examining kinetic schemes or reaction mechanisms, and in identifying rate-controlling processes. An example involving the methanol-to-gasoline synthesis is given to illustrate the method.

Cocoa beans are found inside an outer husk; 60% of the cocoa fruit is the outer husk, which is a waste biomass. The husk cannot be used directly as a soil amendment as it promotes the fungal black pod disease, which reduces crop yield. The pods are segregated from the trees, and their plant nutrient value is wasted. This is particularly true for the small acreage farmers in West Africa. Cocoa pod husk is well suited to be used as a biomass source for electricity production. The waste ash is rich in potassium, which can be converted in various chemical products, most notably, high-purity potassium carbonate. This study reviews the information known about cocoa and cocoa pod husk, and considers the socio-economic implications of creating a local economy based on collecting the cocoa pod husk for electricity production, coupled with the processing of the waste ash into various products. The study demonstrates that the concept is feasible, and also identifies the local conditions required to create this sustainable economic process.

The Chemical Engineering program at the University of Toronto has been in existence since 1904. In this first statistical study of graduating student performance, 10 years of student data have been analyzed. Data for more than 1100 graduated students were evaluated in the core mathematics and engineering science courses. There are no gender-based or visa/residency status-based differences in the cGPA (cumulative GPA) at graduation. Further, there is no gender-based difference in the performance in the mathematics and engineering science courses. However, students on study visas outperform their Domestic and Permanent Resident peers regardless of gender, and the difference persists into the upper years even though the concepts involved have been taught in our program. Students' life-long learning attribute has been investigated through analysis of completions of engineering minors and certificates. Nearly 60% of students graduate with at least one minor, and female students are 10% more likely to complete a minor than their male peers. Domestic female students are much more likely to complete minors in bioengineering or environmental engineering, whereas their male peers and study visa students are more likely to complete minors in sustainable energy. The implications for curriculum changes and faculty teaching assignments are discussed.