Department of Chemical Engineering (Fredericton)

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Adsorption of Pb (II) ions from water using magnetically modified biochars obtained from microwave-assisted pyrolysis
Adsorption of Pb (II) ions from water using magnetically modified biochars obtained from microwave-assisted pyrolysis
by Patrick Muesi Godwin, In this study, biochars were produced from biomass at pilot scale in a microwave-assisted pyrolysis process. These pyrolyzed biochars were magnetically modified to improve their adsorption performance and facilitate the recovery of the spent biochars from solution. The magnetic chars were investigated as a potential renewable bio-sorbents for removing lead ions from aqueous solution in a batch-mode experiment. The biochar samples from microwave pyrolysis of 1.5 kg hemp stalks and maple wood chips biomass at a temperature range of 500–700 ˚C were first impregnated with H[subscript 2]O[subscript 2] (30%) solution and then magnetized by mixing aqueous Fe[superscript 3+]/Fe[superscript 2+] solution with biochar suspensions, followed by NaOH treatment. The synthesized magnetic adsorbents were characterized. The effects of temperature, pH, dosage, contact time and initial concentration of Pb (II) solution on adsorption were examined. Adsorption kinetics and isotherm of the modified biochars were modelled and their adsorption performance after 5 regeneration cycles quantified. The adsorbents recovery from solution with a low magnetic field was investigated. The prepared magnetic biochars demonstrated a potential as renewable adsorbents in treating lead ions-contaminated water. Keywords: Microwave-pyrolysis; Magnetic biochar; hemp; maple; adsorbent; water treatment; heavy metal ions.
An engineering and economic viability assessment of converting municipal sewage sludge to biocrude via hydrothermal liquefaction (HTL) and catalytic hydrothermal gasification (CHG)
An engineering and economic viability assessment of converting municipal sewage sludge to biocrude via hydrothermal liquefaction (HTL) and catalytic hydrothermal gasification (CHG)
by Andrew Mergl, The economic feasibility of a combined hydrothermal liquefaction (HTL) and catalytic hydrothermal gasification (CHG) process using municipal sewage sludge (MSS) as a feedstock was investigated. A predictive economic model was prepared to determine the areas within the process with the largest economic influence of the design. Laboratory experiments were focused on varying the temperature (280-320°C), residence time (10-40 minutes), and feedstock solids content (5-20wt%) of a batch HTL reaction using local MSS samples. Data from the experiments were input into the model to provide Chief Defense Contractors Inc. an engineering assessment of the proposed process. Economic results indicate that with sufficient feedstock/product flow there exists several scenarios with positive net present values. Experimental data suggests that higher operating temperatures and feedstock solids contents are favourable towards the conversion of carbon from MSS to biocrude.
An investigation of iron concentration effects and modelling of flow accelerated corrosion
An investigation of iron concentration effects and modelling of flow accelerated corrosion
by Michael Alexander Briggs, Flow accelerated corrosion (FAC) is an aggressive form of degradation in power plant piping that leads to substantial wall thinning and sudden failures. An interaction of a complex series of mechanisms, FAC is difficult to detect, requiring predictive tools to identify susceptible components and guide the deployment of mitigating measures. An experimental investigation has been carried out examining the e↵ect of changes in iron concentration on the rate of FAC. A sampling system and process were developed to measure bulk iron concentration in concert with measured FAC rates in an experimental probe at temperature. The UNB mechanistic model has been updated to provide an improved response to variations in bulk iron concentration. The model has also been updated to respond more e↵ectively to mass transfer variations in order to model complex geometry and highly turbulent flow.
Applications of selected chemical additives to decrease pulp fibre network strength and their relation to pipeline plug removal in an industrial setting
Applications of selected chemical additives to decrease pulp fibre network strength and their relation to pipeline plug removal in an industrial setting
by Ryan Christensen, A common issue in pulp and paper operations is the blockage of pipelines by plugs of compacted fibre networks, resulting in time consuming and costly procedures being employed for plug removal. A laboratory set-up was established and then used to measure the break-up pressure of fibre-based plugs, which provided an indication of the fibre network strength. Selected chemical additives, namely cupriethylenediamine (CED) and cationic polyacrylamide (C-PAM), were investigated to determine their ability to decrease the fibre network strength and therefore decrease the pressure required for plug removal. The results demonstrated that CED can decrease the network strength through partial fibre dissolution while C-PAM reduces network strength through inter-fibre friction reduction. Both chemical additives have potential to be used in the pulp and paper industry for resolving and/or improving issues arising from fibre-based plugs.
Bio-nanocomposites for enhancing water vapor barrier of cellulose-based packaging materials
Bio-nanocomposites for enhancing water vapor barrier of cellulose-based packaging materials
by Madjid Farmahini-Farahani, The use of renewable materials within the packaging industry has gained increasing interest in recent years. Cellulose fiber is the most abundant biopolymer on planet earth due to it is sustainable, biodegradable and environmental friendly nature, it is widely utilized in many fields. However, the barrier properties of porous and hydrophilic cellulose fiber network products are inadequate for most barrier applications. In order to improve its barrier properties and widen its applications, extensive studies have been carried out in the current thesis work. In the first section, two biopolymers, poly lactic acid (PLA), poly (3-hydroxybutyrate-co-4-hydroxybutyrate), (PHBV) and their nanocomposites with different nanoclays and with various clay contents were coated on paper. Moreover, various coating methods were also used to control the hydrophilic surface and cover the porous structure of paper in an attempt to improve the water vapor resistance of paper products. It was found that the coating method and clay exfoliation were the most important factors affecting water vapor permeability. The papers coated with exfoliated PHBV nanocomposites drastically improved the water vapor barrier of the paper by lowering the water vapor transmission rate (WVTR) to a level that is similar to those of polypropylene (PP) and low density polyethylene (LDPE). In the second section, a simple route was used to produce regenerated cellulose and regenerated cellulose nanocomposites with sodium-montmorillonite (Na-MMT). A series of novel modified montmorillonites were prepared via solution blending in aqueous alkaline/urea solvent at low temperatures, followed by regeneration of films. The effect of nanoclays loading on the mechanical, crystallinity and water vapor transmission properties of the nanocomposites was investigated. Generally, nanoclays loading improved the mechanical and water vapor barrier properties of the cellulose films. Although, the WVTR values of the resulted nanoclay-cellulose films was much lower than regular paper, but the WVTR values remain much higher than most of the fossil-based polymers.
Catalytic co-conversion of glycerol and proton-donor species to gasoline-range aromatics over alumina
Catalytic co-conversion of glycerol and proton-donor species to gasoline-range aromatics over alumina
by Arian Shahnazari, Glycerol is the main by-product of the biodiesel production process. Saturation of this by-product in the market would negatively affect the growth of biodiesel production industry. Due to complexities in the purification processes of crude-glycerol, less costly chemical conversion of glycerol to value-added products and feedstocks such as propenal and aromatics has gained more attention recently. In this work, the influence of co-feeding proton-donor and olefin-donor species on the catalytic conversion of glycerol over alumina catalyst to gasoline-range aromatics is studied. During the individual catalytic conversion of glycerol over alumina, because of the shortage of proton-donor intermediates in the process and high activity of glycerol on alumina at 470℃, glycerol mostly leads to form high carbon deposit content and aqueous phase stream, but less liquid organic production. Introducing methanol and ethanol as compound models of alcohols, and dodecane and hexadecane as compound models of long-chain alkanes next to glycerol remarkably decreases the formation of undesired stream, while selectivity to aromatics substantially increases. In terms of liquid aromatics generation and restricting the excessive carbonization on the catalyst surface, co-feeding 25 wt.% hexadecane with 75 wt.% glycerol has the highest efficiency among the selected compound models; with increasing the liquid aromatics selectivity from 17.7% to 42.5%. Additionally, Co-processing the latter compound model, noticeably shifts the distribution of produced aromatics from heavy undesired aromatics range to the gasoline-range aromatics such as xylenes and toluene. The potential influence of hexadecane on the glycerol to aromatics reaction pathway over alumina catalyst is also proposed, and the effective reactions between glycerol and hexadecane intermediates are discussed. It is also found that selecting a very high or low operational temperature would inversely affect the optimization of aromatics formation through the co-processing runs of glycerol and hexadecane.
Characterization of a flexible nanocomposite material for tactile sensing
Characterization of a flexible nanocomposite material for tactile sensing
by Árpád Körmendy, This project investigates a new soft, flexible piezoresistive composite material, fabricated from Sylgard® 184 silicone elastomer and generic carbon nanotubes (CNTs). This explorative project specifically investigates the overall material production procedure and measurement methods in an attempt to understand and characterize the material properties. The material production method will show that employing sonication mixing of CNTs in chloroform solvent overcomes the characteristic clumping behaviour that prevents uniform dispersion of the filler in solution. This study explores the importance of the heat curing process and demonstrates the difficulties in the fabrication process. The bulk resistance of the material is measured using both ASTM standards and by a custom created 20-point uniformity measurement device. A selection of electrode materials are tested and compared to see the effect of surface resistance in attempt to measure the uniformity of the bulk resistance. This study reports the creation of a pressure sensitive composite material following a developed material recipe, demonstrates the effectiveness of CNT dispersion in Sylgard by means of sonication, that the average bulk resistance is best measured using the ASTM standard method and demonstrating that the developed 20-Point test method is a viable means of measuring resistive uniformity under dynamic force loading.
Characterization of oxide films grown by flow-accelerated corrosion using scanning electron microscope (SEM) and focused ion beam (FIB) techniques
Characterization of oxide films grown by flow-accelerated corrosion using scanning electron microscope (SEM) and focused ion beam (FIB) techniques
by Cale MacLennan, Flow-Accelerated corrosion (FAC) has remained an issue in steam raising power plants with FAC being the cause of enhanced degradation of plant piping and if the degradation continues it can develop into unexpected pipe wall failure. Therefore understanding the mechanisms of FAC is necessary in order to predict where it will occur and what can be done to mitigate it. To this end a morphology study was conducted on probes corroded by FAC in various conditions. By observing the changes in oxide layer morphology in response to changes in system conditions more information about the mechanisms of FAC can be inferred. The information gained from the morphology study was then used to update the UNB mechanistic model to improve the accuracy of its predictions. After updating the model, it was able to predict FAC rates and oxide thicknesses quite well in both neutral and ammoniated conditions for two different compositions of steel.
Controlled surfactant adsorption and release within oil formations for enhanced oil recovery
Controlled surfactant adsorption and release within oil formations for enhanced oil recovery
by Hassan Mahdi Alhassawi, The adsorption of surfactants onto solid surfaces is a major issue during chemical enhanced oil recovery (EOR) applications. Surfactant adsorption reduces the performance of the chemical injection slug and makes the process uneconomical. In this research, a new surfactant delivery system SDS:-CD inclusion complex, was evaluated as an approach to decrease surfactant adsorption. The effectiveness of this system on the surfactant adsorptive behavior was determined through static and dynamic adsorption tests. Likewise, the performance of this approach during EOR surfactant flooding was investigated through sandpack displacement tests under simulated oil reservoir conditions. The research outcomes indicate that this new technology is greatly efficient in reducing the adsorption of surfactant onto solid surfaces. Sandpack testing demonstrated that the surfactant is released at the oil saturation zones within the sandpack and higher incremental oil was recovered in comparison with the conventional EOR surfactant flooding. This technology has great potential for EOR applications., Electronic Only. (UNB thesis number) Thesis 9340. (OCoLC) 961213660., M.Sc.E., University of New Brunswick, Department of Chemical Engineering, 2014.
Density functional theory studies of furfural hydrodeoxygenations on various catalysts
Density functional theory studies of furfural hydrodeoxygenations on various catalysts
by He Dong, Furfural conversions via hydrodeoxygenation pathways were thoroughly investigated by using density functional theory (DFT) calculations on the Ru/Co3O4 surface, Re/Pt bimetallic system, and Ni2P (0001) surface, respectively. On the Ru/Co3O4 surface, it was found that an oxygen vacancy was necessary to be generated in the form of water for the subsequent hydrodeoxygenation of furfural. In order to generate 2-methylfuran, the reaction initiated from hydrogenation of furfural into furyl–CH2O alkoxide intermediate, followed by C–O bond cleavage, and finally the hydrogenation of the unsaturated furyl–CH2 species. This reaction pathway was both kinetically and thermodynamically facile. Comparing with the group X metals and ruthenium, the decarbonylation pathway to produce furan and carbon monoxide was inhibited on Ru/Co3O4 surface by the adsorption geometry. In the Re/Pt bimetallic system, it was found that the kinetically favoured product was furfuryl alcohol, while the 2-methylfuran and water were the thermodynamically favoured products. Based on the calculations, the hydrodeoxygenation product 2-methylfuran was achievable via the hydrogenation of furfural into hydroxyalkyl species, followed by C–OH bond cleavage, and successive hydrogenations of the furyl–CH intermediate. However, the production of 2-methylfuran was prohibited as the oxidised Re surface cannot accept further oxygen deposition, because the removal of oxygen in the form of water via hydrogenations was difficult at the experimental condition. Comparing the results from the Re/Pt system with those on a monometallic flat Pt surface, we were able to demonstrate that incorporation of the oxophilic metals to active hydrogenation metals could promote the hydrodeoxygenation route by reducing the barrier of C–O bond cleavage. As the Ni3P2-termination was more stable than the Ni3P1-termination in Ni2P (0001) surface, it was mainly focused in the calculations. The generation of 2-methylfuran was favoured via hydrogenation to hydroxyalkyl species, followed by the cleavage of C-OH bond and successive hydrogenations, which indicated that the furfuryl alcohol was not a necessary intermediate for the 2-methylfuran formation. During the further conversion of 2-methylfuran, the ring-hydrogenation pathway to generate 2-methyltetrahydrofuran was kinetically favoured than the ring-opening pathway to produce 2-pentanone. The formation of difurfuryl ether could not be achieved without the participation of phosphorus. The adsorption geometry of furfural was the main factor which inhibited the decarbonylation reaction to generate furan on Ni3P2-termination. Based on the comparisons of these three systems for the hydrodeoxygenation of furfural, Ru/Co3O4 system was the best choice which led to a high selectivity of the desire product 2-methylfuran while inhibited the by-products formation., Chemical formula numbers in abstract should be subscripts
Detoxification of C5 rich prehydrolysate from FPInnovations modified TMP-Bio process for lactic acid fermentation
Detoxification of C5 rich prehydrolysate from FPInnovations modified TMP-Bio process for lactic acid fermentation
by Kalian Hiew, This work studied a combination of methods for detoxifying prehydrolysate produced by FPInnovations’ modified TMP-Bio process from hard wood chips for fermentation based bio-refining. The optimal conditions for pH adjustment based removal of fermentation inhibiting compounds was investigated as well as the results of further refining overlimed pressate by membrane filtration in order to remove additional inhibitors. Initial pH adjustment to 11 with continual stirring in a 25°C water bath removed between 14-19% of the total phenols detected in the pressate (in vanillin equivalents), while reducing the concentration of xylose by 25-28%. Samples were subsequently passed through membrane filtration at 200Da, removing up to 28% of the acetic acid detected after overliming. Dilute pressate samples treated with this combination of detoxification steps was fermentable by Bacillus coagulans, consuming 97% or greater of the available xylose within 24 hours., Graduation booklet notes degree is Master of Science in Engineering (MScE) and document is a thesis.

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