Gregory Patience | École Polytechnique de Montréal (original) (raw)

Papers by Gregory Patience

Applied Catalysis B-environmental, Jun 1, 2021

Abstract Stranded natural gas is economically unattractive due to high operating and investment c... more Abstract Stranded natural gas is economically unattractive due to high operating and investment costs of conventional technologies necessary to bring it to market. However, milli-second reactors operating at a GHSV up to 200 000 h−1 reduce investment. The first step of a gas-to-liquids process produces syngas—a mixture of CO and H2. Here, we propose promoted Ni-based catalysts supported on FeCrAl knitted gauze to partially oxidize CH4 in air to syngas. High syngas selectivities at 1 bar, 700 °C and CH4/O2 ratios of 2.5 to 5 suggests an apparent direct reaction path to CO and H2. Ru promoted catalysts had higher turnover rates in CH4 activation compared to Ni, Ni-Pt and Ni-Pt-Ru. All catalysts containing Pt formed carbon species refractory to air regeneration at 700 °C. 2.25% Ni with 0.1% Ru had the highest CH4 turnover rate (155 mol s−1 mol−1) and CO selectivity (80%) at a CH4/O2 ratio 2.5. CH4 conversion and CO production were constant after 50 reaction-regeneration cycles that dosed the catalyst for 25 min with methane/air followed by an equal time in air at the same reaction temperature.

Chemical Engineering Journal, 2020

Converting waste associated natural gas from oil fields is uneconomic with current gas-to-liquid ... more Converting waste associated natural gas from oil fields is uneconomic with current gas-to-liquid technology. Micro Gas-to-Liquids technology (μGtL) combines process intensification and numbering up economics to reduce capital costs to convert flared and vented natural gas to value-added synthetic fuel: Millisecond contact times in the catalytic partial oxidation of methane (CPOX) integrated with a tandem Fischer-Tropsch (FT) step meets the economic constraints together with remote process control. FeCralloy knitted fibres with high thermal conductivity and low pressure drop, resist thermal and mechanical stresses in the high pressure CPOX step. The FeCralloy catalysts are free of pre-reduction treatments. We deposited Pt and/or CeO 2 over the fibre surface via solution combustion synthesis. Methane conversion was higher at ambient pressure compared to 2 MPa while the Pt/CeO 2 FeCralloy was relatively inert from 0.1 MPa to 2 MPa. However, both catalysts demonstrated high activity in quasi-chemical looping partial oxidation of methane: during the reduction step while feeding methane, an on-line mass spectrometer only detected H 2 while in the oxidation step it detected predominantly CO. Kinetic modeling of the oxidation-reduction cycles suggests that the reaction follows a direct mechanism to produce CO and H 2 rather than an indirect mechanism that first produces CO 2 and H 2 O followed by reforming.

Catalysis Communications, Sep 1, 2017

Formation of iron pentacarbonyl in a pressurized CO cylinder changes the photoreaction path Photo... more Formation of iron pentacarbonyl in a pressurized CO cylinder changes the photoreaction path Photoreaction highly depends on the UV wavelength under atmospheric pressure Fe(CO) and Fe are substantial species which play the role of catalytic initiators *Highlights (for review)

Catalysis Today, Jul 1, 2016

Abstract μ-Gas-to-Liquids technology (μ-GTL) can potentially reduce natural gas that is flared th... more Abstract μ-Gas-to-Liquids technology (μ-GTL) can potentially reduce natural gas that is flared throughout the world. Integrating syngas production (at high pressure) together with Fischer–Tropsch in the same vessel addresses both investment costs and operating costs challenges related to μ-GTL. Pt on a Fecralloy woven metal support effectively oxidizes methane in the presence of O2/Ar mixtures. Both CO and H2 selectivity are higher over the Fecralloy compared to either a commercial Pt-gauze or a Pt/Rh gauze at 900 °C and 20 bar. The catalyst activity is stable over 1 h but the 80–300 nm Pt particles agglomerate and form popcorn shape particles that are as large as 1150 nm.

Processes

Research on cannabis oil has evolved to encompass the pharmaceutical industry for the therapeutic... more Research on cannabis oil has evolved to encompass the pharmaceutical industry for the therapeutic potential of the active compounds for pathologies such as Alzheimer, auto-immune disorders, and cancer. These debilitating diseases are best treated with cannabinoids such as tetrahydrocannabinol (∆9-THC), cannabigerol (CBG), and cannabinol (CBN), which relieve neuropathic pain and stimulate the immune system. We extracted cannabinoids from plants with supercritical CO2 and produced an extract with a total yield close to 26%. The three-level Box–Behnken experimental design considered four factors: Temperature, pressure, CO2 flow rate, and processing time, with predetermined parameters at low, medium, and high levels. The mathematical model was evaluated by regression analysis. The yield of ∆9-THC and CBG reached a maximum after 2 h and 15 g/min of CO2, 235 bar, 55 °C (64.3 g THC/100 g of raw material and 4.6 g CBG/100 g of raw material). After another 2 h of extraction time, the yield o...

Social Science Research Network, 2022

Journal of CO2 Utilization

Production of Biofuels and Chemicals with Ultrasound, 2014

Mass transfer is a rate limiting step in biodiesel production. Ultrasound can accelerate tremendo... more Mass transfer is a rate limiting step in biodiesel production. Ultrasound can accelerate tremendously the mass transfer in both triglycerides transesterification and free fatty acid esterification by finely emulsifying reagents that are poorly miscible. We describe reactor configurations for both transesterification and esterification, with emphasis on the work published by the authors. Ultrasound in the esterification increases the mass transfer in raw oils at temperatures below 40 °C. The Eley–Rideal kinetic model of the esterification including the mass transfer resistance between the phases is in excellent agreement with the experimental data. The Rosett cell reactor combines acoustic cavitation and turbulence and transesterifies 90 % of the feedstock in 5 min, whereas it takes 90 min in a conventional batch reactor. Continuous and semi-continuous tubular reactors irradiated at a power density of 40 kW/cm3 converts 90 % of the oil in 10 min. A Sonitube® (Synetude) converts 90 % of the oil after a single passage in a continuous reactor. This corresponds to 18 s and a rate 300 times faster than the conventional process. Sonitube ® improves mass transfer substantially and is worthy of scaling up.

Spray dried fluidized bed catalysts belong to the Geldart Group A classification and vary between... more Spray dried fluidized bed catalysts belong to the Geldart Group A classification and vary between 22 m to 200 m in diameter (1). Binder is either distributed throughout the particle with the active phase or surrounds the active phase as in a core-shell structure (2, 3). We slurried WO3/TiO2 micronized powder (0.2 m to 2 m) with colloidal silica (LUDOX HS-40) to form a slurry with a mass fraction of 5 % to 20 % solids. The solution entered the top of GB-22 Yamato fluidized bed spray dryer chamber (0.12 m ID) through a two-fluid nozzle and the drying air entered the bottom counter-currently. We varied the feed slurry concentration, binder concentration, slurry and drying air flow rates, two-phase nozzle pressure drop and inlet temperature.

Education for Chemical Engineers, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Journal of Power Sources, 2020

The growing market for electrical vehicles requires inexpensive, long-lasting batteries. LiFePO 4... more The growing market for electrical vehicles requires inexpensive, long-lasting batteries. LiFePO 4 (LFP) melt-synthesized from ore concentrate fits this role, but the manufacturing process requires additional steps that includes grinding large ingots into a nanoparticle suspension followed by a dessication step. Spray drying, rather than tray drying, creates a mesoporous powder that enhances wettability. Adding lactose and high-M w polyvinyl alcohol (PVA) to the suspension of nanostructures followed by pyrolysis, creates a carbon-cage that interconnects the cathode nanoparticles, imparting better capacity (LiFePO 4 /C: 161 mA h g −1 at 0.1C), discharge rate (flat plateau, 145 mA h g −1 at 5C), and cyclablity (91 % capacity retention after 750 cycles at 1C). Particle size affects battery stability; PVA increases the suspension's viscosity and alters the powder morphology, from spherical to hollow particles. A model describes the non-Newtonian suspension's rheology changing: shear, temperature, LFP and PVA loading. Carbon precursors prevent the nanoparticles from sintering during calcination but lactose gasifies 50 % of the carbon, according to the chemical and allotropic composition measurements (CS analyzer, XPS, and Raman). The carbon-cage imparts microporosity and we correlate the SEM and TEM powder's morphology with N 2 physisorption porosimetry. Ultrasonication of the suspension fragments the PVA chain, which is detrimental to the final cathode performance.

Journal of Food Engineering, 2020

Abstract Green tea (Camellia sinensis) leaves are particularly rich in polyphenols. Here we propo... more Abstract Green tea (Camellia sinensis) leaves are particularly rich in polyphenols. Here we propose the clarification of green tea extract by an innovative process consisting of a two-stage filtration through asymmetric alumina (Al2O3) hollow fibers, which we specially designed for this application by the phase inversion technique. The fibers presented outer sponge like-layers, mainly responsible for the membrane selectivity (turbidity of green tea extract was reduced by 90%) and mechanical strength (135 MPa), and an inner finger-like layer that reduced the resistance to flux permeation (water permeability of 2.56 × 10−9 m3 s−1 m−2 Pa−1). In order to increase the membrane retention coefficient, we deposited a polyethersulfone (PES) coating layer on the fiber outer surface. This polymeric layer further reduced the green tea extract turbidity by 97.8% in the permeate. As a consequence, no team cream formed even after 30 days of refrigerated storage. Thus, the membranes that we conceived enabled to obtain a product with superior clarity and stability. Additionally, a mathematical description of flux decay during the filtration processes showed that cake formation and internal pore blockage models better described flux decay through Al2O3 and PES/Al2O3 hollow fibers, respectively.

Applied Catalysis A: General, 2018

Heteropoly acids are among the best catalysts to produce carboxylic acids from light hydrocarbons... more Heteropoly acids are among the best catalysts to produce carboxylic acids from light hydrocarbons. The Keggin structure maintains metals at a high oxidation particularly in the presence of cesium, vanadium, and copper. They effectively catalyze the partial oxidation of 2-methyl-1,3-propanediol (2MPDO)-a co-product in the hydroformylation of allyl alchol to 1-4 butanediol. Converting 2MPDO to methacrylic acid would improve the economics of this route to 1-4 butanediol. Here, we establish the relationship between heteropoly acid performance and calcination temperature at 300 • C and 350 • C. The molybdenum oxidation state was higher after the high temperature treatment but it reduced to a greater extent during reaction (from Mo 6+ to Mo 5+). The higher extent of reduction confirms the higher O 2-→ Mo 6+ charge-transfer in the Keggin anion. Maximum MAA and MAC selectivities were 61 % and 28 %, respectively at 250 • C after 480 min over cycling oxidation-reduction and 2MPDO/O 2 /Ar= 13/10/77 as the best reaction condition and feed composition. Though, the route of direct dehydration of 2MPDO (C−OH bond cleavage) followed by oxidation to MAC is the most direct path to the products detected, we propose a mechanism that passes through the homolitic dissociation of the tertiary C−H bond, in reason of the very similar bonding energies.

Scientific reports, Jan 2, 2018

Malaria devastates sub-Saharan Africa; the World Health Organization (WHO) estimates that 212 mil... more Malaria devastates sub-Saharan Africa; the World Health Organization (WHO) estimates that 212 million people contract malaria annually and that the plasmodium virus will kill 419 000 in 2017. The disease affects rural populations who have the least economic means to fight it. Impregnated mosquito nets have reduced the mortality rate but the Anopheles mosquitoes are changing their feeding patterns and have become more active at dusk and early morning rather than after 22h00 as an adaptation to the nets. Everyone is susceptible to the Anopheles at these times but infants and pregnant women are the most vulnerable to the disease. Plant-based mosquito repellents are as effective as synthetic repellents that protect people from bites. They are sustainable preventative measures against malaria not only because of their efficacy but because the local population can produce and distribute them, which represents a source of economic growth for rural areas. Here, we extract and test the essen...

Heliyon, 2017

Databases catalogue the corpus of research literature into scientific categories and report class... more Databases catalogue the corpus of research literature into scientific categories and report classes of bibliometric data such as the number of citations to articles, the number of authors, journals, funding agencies, institutes, references, etc. The number of articles and citations in a category are gauges of productivity and scientific impact but a quantitative basis to compare researchers between categories is limited. Here, we compile a list of bibliometric indicators for 236 science categories and citation rates of the 500 most cited articles of each category. The number of citations per paper vary by several orders of magnitude and are highest in multidisciplinary sciences, general internal medicine, and biochemistry and lowest in literature, poetry, and dance. A regression model demonstrates that citation rates to the top articles in each category increase with the square root of the number of articles in a category and decrease proportionately with the age of the references: ...