School of Chemical and Metallurgical Engineering
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Item Lignocellulosic Bioethanol Production from Grasses Pre-treated with Acid Mine Drainage: Modeling and Comparison of SHF and SSF(Elsevier, 2019-09-01) Burman, N.W.; Sheridan, C.M.; Harding, K.G.Acid mine drainage (AMD) was used for the pre-treatment of indigenous South African grass (Eragrostis curvula), and compared to H2SO4 (1 wt%) pre-treatment. The optimal pre-treatment duration were investigated and found to be 1 day for H2SO4 and 3 days for AMD pre-treatment. The optimal biomass solid loadings were found to be 20 wt% for both pre-treatment methods. Additionally, enzymatic hydrolysis and fermentation to produce ethanol were investigated for both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF). In both SHF and SSF, the H2SO4 pre-treatment obtained higher concentrations of glucose/ethanol compared to AMD pre-treatment. The concentration of glucose/ethanol obtained using AMD pre-treatment was 70–80% of that achieved using H2SO4 pre-treatment. Empirical equations modeling the glucose/ethanol concentration in all processes were determined using a least squares method. Concentrations predicted by the models were found to have a high correlation (r2 = 0.87–0.99) to concentrations determined experimentallyItem Modelling of Low Temperature Dilute Sulfuric Acid Pre-treatment of South African Grass(Elsevier, 2018-12-01) Burman, N.W.; Sheridan, C.; van Dyk, L.; Harding, K.G.Dilute acid hydrolysis is an effective method of pre-treatment of lignocellulosic biomass. Although there are many studies modelling this pre-treatment at high temperature (120–210 °C), no studies were found modelling this reaction at low temperature. In this study, a long grass species was pre-treated with dilute sulfuric acid (pH 1, 2 & 3) at low temperatures (35 °C, 65 °C, 90 °C). The hydrolysis of xylan was found to obey a bi-phasic model in which there are two fractions of xylan, with significantly different hydrolysis rates. The rates of hydrolysis of the fast reacting fraction was found to obey Arrhenius type temperature dependence (Ea = 155.06 kJ/mol, A0 = 1.65 × 1019/min), which agrees with findings of similar studies at higher temperatures. A negligible rate of hydrolysis was determined for the slow fraction which differs from previous studies. The proportion of the slow reacting fraction (50%) which is lower than previously determined (55%–100%).Item Dealing with Under-Preparedness in Engineering Education Part 1: Defining the Goal: A Taxonomy of Engineering Competency.(American Society for Engineering Education., 2003) Woollacott, L.C.This paper emerges from work conducted on the problem of effectively addressing under-preparedness in entrants to university engineering programs in South Africa. Any educational curriculum is based on a conception of the developmental journey a learner must take in becoming a competent graduate. The conceptions underlying traditional engineering curricula do not match well with the journeys that under-prepared students with ability should take to reach their potential fully. To work towards a better match between conception and reality requires deeper understanding of the nature of under-preparedness, of engineering competency and of the determinants of engineering competency (that is, the underlying factors that determine the quality of the competencies). The first of these areas will inform the process of curriculum design by clarifying the starting point of the developmental journey. The second area will clarify the goal and the third will help to clarify what must be done to get there. This paper addresses the second of these issues –understanding engineering competency. Eight different perspectives on engineering competency have been extracted from the literature and a ninth is developed in the paper. Analysis of their similarities and differences provides a basis for developing a broader, integrated perspective that is presented as a taxonomy of engineering competency. How the taxonomy is used in acquiring a deeper understanding of competency determinants and under-preparedness will be explored in two follow up papers.Item The low temperature oxidation of coal: its kinetics and implications for spontaneous combustion(2010-01-19T10:14:14Z) Itay, MItem Characterisation of metallurgical reductants on the basis of reactivity(2010-01-19T09:53:15Z) Kok, HermanItem Dealing with under-preparedness in engineering education. Part 1: Defining the goal. A taxonomy of engineering competency.(2008-07-10T11:37:22Z) Woollacott, L.C.This paper emerges from work conducted on the problem of effectively addressing under-preparedness in entrants to university engineering programs in South Africa. Any educational curriculum is based on a conception of the developmental journey a learner must take in becoming a competent graduate. The conceptions underlying traditional engineering curricula do not match well with the journeys that under-prepared students with ability should take to reach their potential fully. To work towards a better match between conception and reality requires deeper understanding of the nature of under-preparedness, of engineering competency and of the determinants of engineering competency (that is, the underlying factors that determine the quality of the competencies). The first of these areas will inform the process of curriculum design by clarifying the starting point of the developmental journey. The second area will clarify the goal and the third will help to clarify what must be done to get there. This paper addresses the second of these issues –understanding engineering competency. Eight different perspectives on engineering competency have been extracted from the literature and a ninth is developed in the paper. Analysis of their similarities and differences provides a basis for developing a broader, integrated perspective that is presented as a taxonomy of engineering competency. How the taxonomy is used in acquiring a deeper understanding of competency determinants and under-preparedness will be explored in two follow up papers.