Research Outputs (Chemical and Metallurgical Engineering)

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Browsing Research Outputs (Chemical and Metallurgical Engineering) by Author "Burman, N.W."

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    Feasibility assessment of the production of bioethanol from lignocellulosic biomass pretreated with acid mine drainage (AMD)
    (Elsevier, 2020-09-01) Burman, N.W.; Sheridan, C.; Harding, K.G.
    A techno-economic evaluation of a lignocellulosic bioethanol facility that uses acid mine drainage for the pre-treatment of weeping love grass (Eragrostis curvula) was performed. Both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) reactor configurations were evaluated. Results were compared to an evaluation of the same process with biomass pre-treated with dilute H2SO4. Capital and operating costs were estimated and a simple economic evaluation was conducted. It was found that all scenarios made a loss except for biomass pre-treated with H2SO4 in the SHF reactor configuration, although the high capital cost resulted in a payback period of 80.7 years, which is unfeasible. SHF was found to produce more ethanol at a lower capital cost than SSF, indicating that it is more economically feasible. Incorporating the remediation of AMD into a simultaneous process could help improve process economics. It is thus recommended that a techno-economic evaluation be conducted on a process that produces bioethanol through SHF and simultaneously remediates AMD
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    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 experimentally
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    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%).