Browsing by Author "De la Hoz Siegler, Hector"
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- ItemOpen AccessAcoustic Properties of Oil sands(2017) Patel, Gaurav Jayeshbhai; Gates, Ian Donald; Chen, Shengnan; De la Hoz Siegler, HectorA well-known, efficient and economical method to recover bitumen from oil sand reservoirs is the Steam-Assisted Gravity Drainage (SAGD) process. To monitor this recovery process, each year, operators conduct seismic shoots of the formation and from the interpretation of the data, they estimate the vertical and areal extents of the steam chambers around the SAGD well pairs within the reservoir. One of the important property that is required to process seismic data is the speed of sound in oil sands and bitumen. A lot of laboratory data is available on velocity in oil sands at different pressure and temperature but nearly all are measured at ultrasonic frequencies which is in the hundreds of thousands of Hz. However, seismic shoots are conducted at between 10 and 100 Hz and it has been shown that there is a significant difference of the speed of sound at ultrasonic and seismic frequencies. In the research, a novel large scale (2.3 m long, 2 5/8 inch diameter) high pressure core holder apparatus has been designed and constructed to measure the speed of sound versus pressure and temperature at seismic frequencies. The data obtained from the new experimental apparatus compares well with data from published literature. The same apparatus has been used to study the audible frequency effects on oil sand as a result of viscous dissipation and on bitumen viscosity.
- ItemOpen AccessAutofermentation of alkaline cyanobacterial biomass to enable biorefinery approach(2023-04-08) Demirkaya, Cigdem; Vadlamani, Agasteswar; Tervahauta, Taina; Strous, Marc; De la Hoz Siegler, HectorAbstract Background Carbon capture using alkaliphilic cyanobacteria can be an energy-efficient and environmentally friendly process for producing bioenergy and bioproducts. The inefficiency of current harvesting and downstream processes, however, hinders large-scale feasibility. The high alkalinity of the biomass also introduces extra challenges, such as potential corrosion, inhibitory effects, or contamination of the final products. Thus, it is critical to identify low cost and energy-efficient downstream processes. Results Autofermentation was investigated as an energy-efficient and low-cost biomass pre-treatment method to reduce pH to levels suitable for downstream processes, enabling the conversion of cyanobacterial biomass into hydrogen and organic acids using cyanobacteria’s own fermentative pathways. Temperature, initial biomass concentration, and oxygen presence were found to affect yield and distribution of organic acids. Autofermentation of alkaline cyanobacterial biomass was found to be a viable approach to produce hydrogen and organic acids simultaneously, while enabling the successful conversion of biomass to biogas. Between 5.8 and 60% of the initial carbon was converted into organic acids, 8.7–25% was obtained as soluble protein, and 16–72% stayed in the biomass. Interestingly, we found that extensive dewatering is not needed to effectively process the alkaline cyanobacterial biomass. Using natural settling as the only harvesting and dewatering method resulted in a slurry with relatively low biomass concentration. Nevertheless, autofermentation of this slurry led to the maximum total organic acid yield (60% C mol/C mol biomass) and hydrogen yield (326.1 µmol/g AFDM). Conclusion Autofermentation is a simple, but highly effective pretreatment that can play a significant role within a cyanobacterial-based biorefinery platform by enabling the conversion of alkaline cyanobacterial biomass into organic acids, hydrogen, and methane via anaerobic digestion without the addition of energy or chemicals.
- ItemOpen AccessCatalytic Hydroprocessing of Tire Pyrolysis Oil Distillates(2022-12-16) Marti, Javier; Pereira-Almao, Pedro R.; De la Hoz Siegler, Hector; Clarke, Matthew AlexanderEnergy demand is still in the rising, as well as the environmental concerns related to the use of fossil fuels to meet it. Hence, the transition to alternative and renewable energy sources has become a priority. The production of tire pyrolysis oil (TPO) to eliminate waste tires and produce atmospheric distillates (IBP343°C) has great potential to reduce the amount of waste material and contribute to the energy transition. This work aimed to study the TPO atmospheric distillates upgrading capabilities using the hydrotreating (HDT) process and a new proprietary group of catalysts. First, catalyst Mo2C/Zeolite (P-1) was tested on a synthetic feedstock composed of model molecules emulating TPO atmospheric distillates. Results proved that the highest conversion of nitrogen and sulfur was achieved at 350°C and 0.3 h-1. Additionally, high conversion selectivity of the nitrogenated compounds was observed based on 100 % conversion of the quinoline model molecule. The previous experiment was followed by testing catalyst P-1 and another catalyst Mo2C/γ-Al2O3 (M-3) using a TPO naphtha/kero fraction (IBP-280°C). This test demonstrated that the acidity of the support was key to achieving higher levels of upgrading, nevertheless, it needed to be balanced with a higher hydrogenating function. Later, another set of experiments was performed using a TPO atmospheric distillates (IBP-343°C) fraction and catalysts M-3, P-2 and P-3, the last two with increasing hydrogenation functions. Results showed that catalyst P-3 reached sulfur and nitrogen levels conversion of 90% and 89%, respectively. Additionally, a study of the HDT products obtained in the last experiment was performed based on the distillation of the product into heavy naphtha (IBP-220°C) and diesel (220-343°C). Characterizing these cuts indicated that aromatic and polar compounds initially present in the heavy naphtha are easier to hydrogenate than those in the diesel fraction. Additionally, partial hydrogenation was observed in both cases due to the reduction of polyaromatic compounds and an increase in the tetralin family. Finally, a study on the reaction severity revealed that temperatures of 350°C, weight hourly space velocity of 0.1 h-1, pressure of 1,500 psig and Vol. H2/Oil of 1,200 are preferred for higher hydrogenation.
- ItemOpen AccessCharacterization and Kinetic Study of Ilmenite Ores for Methane Chemical-Looping Combustion(2018-01-12) Khakpoor, Nima; De la Hoz Siegler, Hector; Mahinpey, Nader; Ponnurangam, Sathish; Nassar, NashaatEmitted carbon dioxide from fossil fuels combustion is one of the most influential greenhouse gases leading to global warming. Chemical-looping combustion (CLC) is one of the most efficient methods for carbon capture, resulting in no energy penalty compared to alternative carbon capture methods. CLC is a nonconventional unmixed combustion process where the fuel and air reactions occur in separate reactors. CLC is, however, still a conceptual process due to a series of technical challenges, mainly related to the oxygen carrier. In particular, there is a need for a low-cost, highly stable oxygen carrier capable of withstanding multiple cycles without loss of its oxygen transport capacity and reactivity. Reactivity and oxygen-transport capacity of Canadian and commercial ilmenite ores in the chemical-looping combustion of methane were investigated in a thermogravimetric analyzer (TGA). Oxygen carrier performance was evaluated in multiple cycles during which Canadian ilmenite oxygen transport capacity increased from 2.7% to 14.2% and the commercial sample maintained an approximately constant oxygen transport capacity at 4.5%. XRD and SEM results indicate that new phases were formed, and surface morphology was transformed significantly during cyclic operation. The latter experimental finding explains the increased oxygen transport capacity of the Canadian ilmenite. Studies on carbon deposition on the ilmenite surface indicate that lower methane partial pressure and reduction temperatures are favorable to effectively prevent this phenomenon. The kinetic grain model (GM) was found satisfactorily to fit reduction rate data obtained at atmospheric pressure. Intrinsic reaction rates and kinetic parameters were assessed, accordingly. The activation energy values of 106.7 ± 10.6 kJ/mol and 95.0 ± 8.5 kJ/mol were estimated for the Canadian and commercial samples, respectively.
- ItemEmbargoDevelopment of Carburization-based Chemical Looping Reforming for Hydrogen Production(2024-05-17) Gomes Camacho, Felipe; Mahinpey, Nader; Benneker, Anne Maria; De la Hoz Siegler, Hector; Van Humbeck, Jeffrey Francis; Patience, Gregory S.Chemical looping reforming technology is among the most promising technologies for syngas and hydrogen production. The results from the assessments in this thesis has presented strong evidence that hydrogen could be produced at lower carbon emissions (18.6% to 53.4% less CO2(eq) emissions) and less expensive cost of production (33.1% less than SMR 85%CCS). In order to solve problems faced by conventional looping reforming, this thesis investigates the introduction of a new reaction pathway – carburization reactions, redefining the conventional system. Firstly, a proof-of-concept provides the insights into the main concept for the introduction of carburization reactions into a chemical looping reforming system. Showcasing a thermodynamic assessment for nine possible metal carbides highlighting the best evaluated metals as tungsten carbide and zirconium carbide with a possibility of generating a syngas quality (H2/CO ratio) of 9 and 16 respectively, however the zirconium required higher temperatures and could produce nitrides during oxidation stage when using air as oxidation agent. Then, a second study was performed to have a better understanding of the reaction. The outcomes showed the carburization reaction is described as a two-step mechanism. The first is a nucleation Avrami Erofe’ev second order and the second a nucleation power law fourth order. Furthermore, the application of the process requires it to be investigated in a simulated environment by the application of AspenPlus. The focus was to evaluate the system in three different cases each with different up and downstream units. The inputs and outputs were used for a life cycle assessment to evaluate the systems environmental burdens. This study presented a decrease in greenhouse gas emissions by at least 25% and up to 57% when compared to current steam methane technologies, proving that this is a promising technology for future hydrogen applications and energy transition pathway. Lastly, the results from the simulation were used in a techno-economic assessment. The outcomes of the economic analysis showed that, in general, the proposed carburization-based chemical looping reforming leads to a lower capital cost (at least 42.25% reduction to steam methane reforming) and hydrogen production costs that could achieve up to 45.93% cost reduction.
- ItemOpen AccessEnhancing the Production of Lipids and Antioxidants in Heterotrophic Cultures of Auxenochlorella protothecoides(2016) Ibarra Vidal, Mary; De la Hoz Siegler, Hector; Kallos, Michael; Chu, AngusAuxenochlorella protothecoides, aside its potential for biofuels, is an excellent source of antioxidants, reaching high lipid productivity under heterotrophic conditions utilizing glucose. Glucose-fed cultures, however, experience chloroplast bleaching affecting antioxidants production. In this study, glycerol, was evaluated as a carbon source at varying carbon-nitrogen ratios in batch-cultures. Glycerol presence in glucose fed-cultures reduced, or completely eliminated, chloroplast bleaching and increased the substrate-to-biomass yield beyond its thermodynamic limit. These results, suggest that glycerol forced the photosynthetic pathway to remain active, resulting in dark carbon fixation through the Calvin-cycle reactions. The maximum cell-density and biomass productivity were 17.60 g/L and 1.91 g/L·d respectively. Cultures grown on only-glycerol showed the highest lipid yield, 149 mg-lipids/g-substrate and antioxidants yield 6.650 µmol-Trolox/g-substrate. These values were higher to those observed with sole-glucose fed-cultures by 7% and 93% respectively. The maximum antioxidant productivity reached was 12.53 µM-TEAC/L•d, value comparable to those previously reported for Haematococcus Pluvialis.
- ItemOpen AccessEsterification of Octanoic Acid over Solid Acid Catalysts Derived from Petroleum Coke(2021-06-28) Schemberger Schafranski, Annelisa; Hill, Josephine M.; Hu, Jinguang; De la Hoz Siegler, HectorPetroleum coke (petcoke) is a solid waste of the oil industry, with limited use due to its high sulfur content (> 6.5 wt%) and other impurities. As a carbon-rich, abundant and inexpensive material, petcoke is a potential resource for carbon-based catalysts. Esterification is a broad, important class of reactions for which carbon-based catalysts have been investigated and applied successfully. The treatment of petcoke (functionalization) with different conditions of temperature, time, and types of acid incorporates surface groups, which are the active sites for the reaction. This study tested the catalytic performance of acid-modified petcoke samples over a model reaction: esterification of octanoic acid with methanol. A commercial catalyst, Amberlyst-15, was used for comparison. The effect of various parameters was evaluated, including stirring speed (200 - 800 rpm), temperature (40 - 80 °C), catalyst loading (1 - 4.5 wt%), and methanol-to-acid molar ratio (40:1 - 10:1). The selectivity of all catalysts was 100% towards the ester yield, with no byproducts from the reaction. The method for the evaluation of catalyst activities was based on kinetic parameters and turnover frequency. The catalytic activity of acidic petcoke samples was comparable to the commercial catalyst in terms of conversion with time at the same reaction conditions, and even higher on a per acid site basis. Based on those results, acid-modified petcoke is a prospective material for catalyzing esterification reactions. Different properties arise from the treatment of petcoke with strong acids. The number of strong acid sites, overall acid strength as well as the surface hydrophobicity all influence the catalytic performance for the esterification reaction. Leaching of active sites was problematic and resulted in almost complete deactivation of the petcoke-derived catalysts. An appropriate balance in the surface hydrophobicity/hydrophilicity and a strong attachment of the active sites to the petcoke surface are required for stability.
- ItemOpen AccessExpansion of Skin-Derived Precursor Cells (SKPs) in Stirred Suspension Bioreactors(2016) Boon, Kathryn; Kallos, Michael; Biernaskie, Jeffrey; Ungrin, Mark; Hart, David; De la Hoz Siegler, HectorSkin-derived precursor cells (SKPs) have potential therapeutic applications for dermal regeneration in patients who have undergone split-thickness skin graft (STSG) surgeries due to severe burns. While these cells are traditionally grown in vitro in static t-flasks, a more standardized, well-controlled culture environment is desirable so that sufficient numbers of cells can be produced for clinical applications. This study outlines a bioprocess which could be used to expand SKPs, and establishes a baseline of how these cells grow in static and bioreactor conditions. Using a 9% total body surface area burn as the baseline, it was determined that a fold expansion of approximately 45 to 270 would be required for a 10 cm² piece of donor skin, assuming all cells isolated proliferate and are of therapeutic benefit. While this is not feasible based on current expansion achieved in bioreactors, this study provides useful information moving forward towards more advanced bioprocess development.
- ItemOpen AccessHistory Matching of a SAGD Well Pair Circulation Phase and Wellbore Completion Design Comparison Using a Discretized Thermal Wellbore Modelling Simulator(2017-12-15) Ayala Rivas, Daniel Alexis; Gates, Ian Donald; De la Hoz Siegler, Hector; Shor, Roman JSteam circulation in the early stages of Steam-Assisted Gravity Drainage (SAGD) is crucial for establishing hydraulic communication between the injector and producer well and the future development of the steam chamber. Steam is the carrier of enthalpy to the reservoir and thus, the evolution of pressure, temperature, and steam quality is important for heat transfer efficiency. In the research reported here, the steam circulation phase of a SAGD well pair is examined in detail taking into account heat loss around the wellbore in the vertical/build section and heat transfer and fluid losses in the lateral section of the well pair. In the model developed, well bore hydraulics is also accounted for by using a discretized wellbore model within a fully implicit coupled thermal reservoir simulator. Field data from the circulation phase was history-matched to calibrate the model and subsequently, five different completion designs were examined to evaluate their thermal efficiency. The results show that completion design impact heat transfer and thermal efficiency of the circulation process.
- ItemOpen AccessImproving Algae Growth Kinetics in Suspension Bioreactors for the Production of Recombinant Proteins(2016) Clark, Brendan Robert; Sen, Arindom; Alcantara, Joenel; Hollenberg, Morley; De la Hoz Siegler, Hector; Gates, Ian; Tay, AndrewMillions of individuals rely on recombinant proteins such as essential biopharmaceuticals. Recently, genetically engineered microalgae have been identified as a potentially inexpensive and fast growing host organism for recombinant protein production. Using Chlamydomonas reinhardtii, a species of unicellular green microalgae, the goal was to improve algal cell growth kinetics, genetically engineer the cells and develop a bioprocess to analyze recombinant protein production. C. reinhardtii growth kinetics were improved under mixotrophic growth conditions using acetate in small scale 10 mL cultures. This process was scaled-up to 500 mL spinner flask suspension bioreactors and through the use of a fed-batch acetate feeding strategy, cell growth rates and maximum cell concentrations were improved. A genetic construct was designed, manufactured, isolated and used to genetically transform C. reinhardtii. A bioprocess was then developed to isolate and analyze protein production rates from these cells. Results indicated product concentrations of 8.44 mg/L of culture.
- ItemOpen AccessIntegration of Advanced Biofuel in Alberta(2019-08-19) Young, Cameron; De la Hoz Siegler, HectorIncreasing production of biofuels is one way for Canada to meet its Paris Agreement targets on greenhouse gas emissions. The production of advanced biofuels from residual biomass is an area of growing interest. Steeper Energy has developed technology for producing an advanced biocrude using hydrothermal liquefaction and has tested methods to upgrade said biocrude into usable liquid fuels. Alberta already has a substantial refining infrastructure, which can co-process biocrude along with oil distillate products. Co-processing can reduce the cost of producing biofuels from residual biomass by leveraging existing processes in a refinery. Co-processing in fluid catalytic crackers and hydrotreaters in Western Canadian refineries could co-process up to 53,000 BPD of biocrude. A lifecycle greenhouse gas intensity assessment found biofuel produced using hydrothermal liquefaction approximately 60% less greenhouse has intensive than diesel produced from crude oil
- ItemOpen AccessNonlinear MPC tracking control and set point control for wastewater treatment processes(2019-01-21) Sadeghassadi, Mahsa; Macnab, Chris J. B.; Westwick, David T.; De la Hoz Siegler, Hector; Nielsen, John; Trifkovic, Milana; Ray, Ajay KumarThis thesis concerns the design of feedback controls of a biological wastewater treatment plant (BWT), specifically the benchmark simulation model number 1, and methods for determining optimal set points. In BWT, biological organisms remove unwanted substances including nitrogen, ammonia, and organic material. The feedback controls can manipulate aeration and flow rates in order to control the dissolved oxygen concentration and nitrite/nitrate concentrations. The most basic function of the feedback controls is to ensure that effluent quality meets a pre-determined environmental standard in an energy-efficient manner. Identifying optimal set points can be as important, or more important, in reducing the contaminants/cost as the feedback/feedforward strategy used to track the set point. Thus, choosing an appropriate nitrate/nitrite and oxygen set point, and then maintaining the set point, defines the important objectives of the current work. Several novel methods are developed and compared with a PI control. Initially, Lyapunov-based adaptive controllers with fuzzy set point regulators are designed for both loops. Compared with the existing methods, the proposed methods demonstrate great potential for improving system performance. Moreover, switching techniques on an external carbon source input are proposed to prevent the risk of too much or too little food and/or too little dissolved oxygen. Then, design of the dissolved oxygen (DO) variable set point is presented in parallel to the DO set point tracking control, based on Artificial Neural Network (ANN) models used for set point design and for prediction within the DO Neural Networks Model Predictive Control (NNMPC) algorithm. The solution of an offline multi-objective optimization problem during the first two days of dry weather conditions is used as the initial set point, and then changes in the moving direction provided by an ANN model. Compared with the existing methods, the proposed method shows ability of reducing the effluent quality and the operational cost simultaneously. Next, a single-optimization problem along with an ANN model designs the nitrate/nitrite set point in order to reduce violations in the ammonium and nitrogen limits. The results prove the near-complete removal of violations by using the proposed method. The method in the last chapter includes a way to adjust set point to respond to varying conditions and a model predictive control scheme, which utilizes a cerebellar model arithmetic computer (CMAC). This controller is an adaptive one, since our model used in the MPC updates on-line and in real-time and can thus change due to unknown and changing dynamics. This technique avoids the need for any a-priori estimation step. The CMAC controller learn the desired control signal in a Lyapunov-stable scheme, which provides a guarantee of uniformly ultimately bounded signals.
- ItemOpen AccessOil Sand Remediation(2021-09) Mislan, Michael; Gates, Ian; De la Hoz Siegler, Hector; Ponnurangam, Sathish; Hu, Jinguang; Gieg, Lisa; Jin, ZhehuiOil sand has become an important part of the Canadian economy. It is also a natural, toxic substance. Bitumen and clay suspensions are discussed in context of their position in the biogeochemical carbon and rock cycles, respectively. In the first section, bitumen is described as a product of soil organic matter matured over geological history affected by microbial and environmental conditions. Biological moieties have been preserved intact inside asphaltene-maltene complexes due to the fact that bitumen is fossilized soil or sedimentary organic matter. Therefore the biodegradation of bitumen by common soil biodegrading enzymes is demonstrated using Lipase, for lipid fats, and Cellulase, which degrades the most abundant photosynthetically produced polysaccharide biomass on earth cellulose. These enzymes are able to hydrolytically release biomolecular fragments from bitumen, refluxing them back into the biosphere and carbon cycle. In the second section, similarly to how sedimentary minerals metamorphosize naturally, mature fine tailings (MFT) is geopolymerized to produce a metamorphic, hydrated zeolite solid. MFT samples in tanks were mixed with 1 kg KOH 1 kg K2SiO3/m3 Raw MFT and shown to solidify after 20 days, demonstrating better performance than many competing remediation techniques. In general it is demonstrated that naturalistic methods for oil sand remediation may be possible because oil sand is a natural geological product of aquatic ecosystems.
- ItemOpen AccessPartial Upgrading of Lignocellulosic Bio-Oil via Deep Catalytic Hydrotreating(2021-09-23) Marashi Shoushtari, Nafees Sadat; Pereira Almao, Pedro; Clarke, Matthew; De la Hoz Siegler, HectorAccording to the International Energy Agency, bioenergy accounts for one-tenth of the world's total primary energy supply and biofuel production is forecasted to increase 25% by 2024. The bio-oil is composed of a complex mixture of oxygenated compounds with a relatively high concentration of water. Compared to crude oil, bio-oil has high oxygen content, lower energy density, high acidity, high viscosity and water content. Submitting the bio-oil to atmospheric distillation at the refinery is not possible at this stage since the highly reactive compounds in the bio-oil will plug the distillation column at high temperatures, and moreover, high temperatures will accelerate the corrosion effect of the bio-oil in the refinery lines. Therefore, an upgrading step is necessary to make the bio-oil admissible to the refinery. The ultimate goal of this research is to produce biofuel equivalent to conventional fuels from lignocellulose-derived bio-oil. The main objective of this study is to reduce the oxygen content of the bio-oil via the catalytic hydrotreating process and to improve the quality of the upgraded oil. The effect of the process variables such as operating pressure, temperature and space velocity on the product quality was studied. The best results were obtained using CAT-M5, at 1750 psig, 370 C and 0.4 h-1 space velocity resulting in 77% reduction in oxygen content, 99.5% reduction in viscosity, 100% reduction in total acid number, 55% phenol conversion and 91% residue conversion. It was found that increasing pressure, unlike temperature, does not have a noticeable effect on microcarbon residue reduction, viscosity, and boiling point distribution of the product, but it improves the degree of deoxygenation and molar H/C ratio. Moreover, at temperatures higher than 350 C, hydrocracking along with hydrogenation notably improved the residue conversion, viscosity and MCR reduction. Comparing the performance of catalysts showed that CAT-M5, unlike CAT-M3, eliminated the solid precipitation in the products thanks to its large pore size. Furthermore, CAT-M5 had a higher residue conversion rate, MCR and viscosity reduction rate. In contrast, CAT-M3 had a better performance in deoxygenation and phenol conversion.
- ItemOpen AccessSplit-Flow Integrated Small-Scale LNG Production Process with Cryogenic Carbon Dioxide Capture(2020-09-28) Ostovar, Arash -; Nassar, Nashaat; Hassanzadeh, Hassan; De la Hoz Siegler, HectorThis thesis addressed three challenges facing the processing of natural gas. First, energy is usually required to produce energy, but it takes more energy to produce liquified natural gas (LNG) than other fossil fuels. In other words, LNG production is a very energy-intensive process, which makes it less competitive. Second, many cryogenic NGL-recovery facilities have been working under full capacity due to low natural gas prices and limited accessible new markets. The last challenge concerns the classic aqueous alkanolamine-based sweetening process, which involves saturating gas with water and restricting the LNG production temperature to be begin from ambient temperature and needs a finishing process to handle the produced acid gas.With a view to address these challenges, first, a novel integrated small-scale LNG process concept was developed that can not only maximize the economic value of NGL recovery facilities but also produce LNG via a more efficient and greener process. This was achieved through comprehensive process simulations, optimizations, and heat integration studies. These studies were performed using the Aspen HYSYS simulation package to find an efficient integrated LNG production process that can use available sources of heating/cooling in a cryogenic NGL-recovery facility without sacrificing the NGL production yield. In the development process, it was determined that an adsorption process (nonsolvent) can remove CO2 at cryogenic temperatures and treat natural gas with the aim of meeting the LNG specification (CO2=50 ppm). This led me to the development of the “split-flow integrated small-scale LNG production process (SFI-LNG)”, which has two main pillars—the cryogenic CO2 removal process and the semi-C3-MR liquefaction process.Second, to validate the cryogenic removal of CO2, zeolite-based adsorbents were synthesized and characterized before they were successfully tested under cryogenic conditions.Third, a bench-scale experimental setup was designed and constructed to prove the concept of cryogenic CO2 removal. Finally, the concept was proven at the bench scale.The principle of cryogenic CO2 removal is based on the selective adsorption of CO2 by a Faujasite (FAU)-based adsorbent under cryogenic conditions, which exhibits a high adsorption rate with great recyclability. In addition, there is no need for a finishing process to deal with acid gas, as highly pure CO2 can be produced as a byproduct.
- ItemOpen AccessStrategies for Improving the Productivity and Cost-effectiveness of Microalgal Production Systems(2016) Canon-Rubio, Karen Andrea; De la Hoz Siegler, Hector; Bergerson, Joule; Hettiaratchi, Patrick; De Visscher, AlexMicroalgae cultivation is a potential solution for renewable energy supply issues and environmental remediation; however, low CO2 absorption rates and volumetric productivities restrain commercial application of algal biotechnology. Mixotrophic and high-alkalinity/high-pH approaches for improving the productivity and cost-effectiveness were evaluated. Although mixotrophic cultivation of Chlamydomonas reinhardtii at low light exposure and high inoculum concentrations showed an improvement in biomass productivity (0.080±0.057 g/L·d in phototrophic experiments versus 0.44±0.163 g/L·d in mixotrophic experiments), values were not sufficient to improve performance of large scale microalgal technology. On the other hand, the high-alkalinity/high-pH approach showed a better performance in terms of lower use of resources and smaller equipment size reflected in three-fold less water requirements, twice the energy return on energy investment (EROI) and four-fold lower production costs (8.03 to 1.63 2013 US$/kg biomass). Economic and environmental results highlight the potential of high–alkalinity/high-pH systems in terms of productivity and cost-effectiveness of microalgal technology.
- ItemOpen AccessStudy on Supported Triamino-functionalized Ionic Liquids for Carbon Dioxide Capture(2021-04-29) Huang, Zhoulan; Mahinpey, Nader; De la Hoz Siegler, Hector; Hu, JinguangThe CO2 capture performance of two novel amino acid ionic liquid (AAIL)-based adsorbents was studied. The sorbents were synthesized by immobilizing two triamino-functionalized ionic liquids (i.e., 1-aminoethyl-3-methylimidazolium lysine ([AEMIM][Lys]) and 1-aminopropyl-3-methylimidazolium lysine ([APMIM][Lys])) into two types of supports (i.e., mesoporous silica SBA-15 and polymer poly(methyl methacrylate) (PMMA)) with different loadings. [AEMIM][Lys] and [APMIM][Lys] with one additional amino group in their cations are efficient at enhancing the CO2 capacity of subsequent supported AAILs, as higher numbers of functional amino groups in AAILs significantly increase their CO2 capture capacity. The prepared samples were characterized by Nuclear Magnetic Resonance (NMR), Brunauer-Emmet-Teller (BET) analysis, thermogravimetric analysis (TGA) decomposition, and X-ray diffraction (XRD). The samples were also investigated for CO2 sorption performance by CO2 isotherms and TGA kinetics. 50 wt% [AEMIM][Lys]-immobilized on PMMA showed the best CO2 capture capacities of 1.5 mmol/g-sorb at adsorption conditions of 30°C and under 15% CO2 inlet concentration.
- ItemOpen AccessStudy on the Kinetics of Dissolution and Reversible Hydration of Carbon Dioxide in Aqueous Solutions(2016-02-04) Zhou, Miao; De la Hoz Siegler, Hector; Hassanzadeh, Hassan; Pereira Almao, Pedro; Du, KeMicroalgal CO2 fixation is an emerging technology for abating CO2 emissions. Microalgal cultures productivity is limited by CO2 transfer rates, as CO2 has low solubility in water and its dissolution is kinetically impaired. Scrubbing and hydration of CO2 into bicarbonate solution prior to feeding the cultures has been proposed to increase CO2 availability. The hydration reaction is the rate-limiting step in the CO2 dissolution process. Experiments were performed to test carbonic anhydrase (CA) and metal (oxide) nanoparticles (MNPs) as catalysts by measuring pH and conductivity changes. A model was developed to predict the reaction process over time and compared to experimental measurements. No catalytic activity was observed for MNPs under all experimental conditions evaluated. Although CA has significant catalytic activity, the mechanism controlling the reaction rate was found (experimentally and numerically) to be mass transfer limitation. Changes in reactor geometry and gas distribution were proved effective to mitigate this limitation.
- ItemOpen AccessThe Biotransformation of Bitumen(2016-01-28) Desance, Ismarck; De la Hoz Siegler, Hector; Gates, Ian Donald; Mahinpey, NaderThree microbial strains (Bacillus lentus, Ganoderma applanatum, Pseudomonas fluorescens) were evaluated for their capacity to biotransform bitumen in suspended and porous media. Bitumen is characterized by high viscosity and low mobility at reservoir conditions, and high toxicity. Microbes capable of biotransforming bitumen might potentially be used for bioremediation and enhanced oil recovery. The microbes grew very well in suspended cultures with bitumen presence. Additionally, results in packed bed cultures indicated that B. lentus in medium E (ATCC-1502) had the higher capability for bitumen bioconversion (42±4%), B. lentus in modified mushroom minimal medium (MMM, 24±7%). A supernatant obtained from B. lentus pretreated with bitumen in medium MMM resulted in (14±4%) conversion, which is the highest in the supernatant group. It was observed that bitumen dispersed and floated to the top of the flask. Bitumen treated with either B. lentus or P. fluorescens has an apparent viscosity lower than no-treated.
- ItemOpen AccessTransitioning an Alkaliphilic and Photosynthetic Microbial Consortium from Laboratory to Outdoor Demonstration Scale(2023-10-05) Haines, Marianne Victoria; Strous, Marc; Strous, Marc; Tutolo, Benjamin M.; Dunfield, Peter F.; De la Hoz Siegler, Hector; Kleinegris, Dorinde M.M.The 21st century’s challenges—climate change, growing population, resource decline, habitat and species loss—mean that current practices must be replaced, redesigned, and improved. Phytoplankton, reliant on water, light, nutrients, and CO2, offer versatile applications in nutritional supplements, agricultural feed, bioplastics, wastewater treatment, and bioenergy production. Currently, the most successful commercial ventures center on select taxa like Spirulina and Chlorella and produce high-value products for human consumption. Expanding the scope of viable commercial taxa and their applications hinges on overcoming critical challenges in cultivation, notably biomass productivity, robustness, and resource use. Inspiration can be drawn from natural environments where phytoplankton flourish, like alkaline soda lakes. These lakes are characterized by elevated pH and high carbonate alkalinity. Growing phytoplankton in high pH (10+), high carbonate alkalinity medium (0.5 M) increases the driving force for CO2 capture into solution and helps exclude competitors and predators which can cause biomass instability. This thesis chronicles the transition of biomass from alkaline soda lakes, dominated by the cyanobacterium Sodalinema alkaliphilum, from laboratory to large-scale outdoor demonstration. Chapter 2 explores the microbes inhabiting such lakes and their societal applications. Chapter 3 describes the design, construction, and operation of laboratory photobioreactors with programmable lighting and online growth measurements. Chapter 4 follows outdoor biomass cultivation in a 1,000 L photobioreactor, demonstrating sustained growth at a pH sufficient for CO2 capture from air. In Chapter 5, cultivation in a 3,000 L open raceway pond (ORP) reports long-term medium re-use, water requirements, and CO2 capture from air, although optimisation is necessary. Operational seasons ranged 70–140 days—160 being the maximum possible in Calgary’s temperate climate. Average daily yields were ∼ 3–4 g/m2/day (ash-free) with modeling predicting productivity could reach 6 g/m2/day by reducing biomass density. Finally, Chapter 6 quantifies ORP biomass losses, with stable isotope probing unveiling insights into S. alkaliphilum physiology and ecology. In conclusion, this research explores the feasibility of growing S. alkaliphilum biomass at scale for extended durations and has generated baseline data and operational insights which can be used to inform and refine the sustainability and productivity of future iterations of this technology.