Mohamed Khalil, PhD Candidate – Chemical Engineering Department, École Polytechnique de Montréal, working under the supervision of Prof. Jamal Chaouki and Prof. Jean-Philippe Harvey, won the 1st place in Polytechnique Montréal’ Ma thèse en 180 secondes / Three Minute Thesis competition (Francophone) and the 2nd place (Anglophone). He’ll represent Polytechnique at the provincial finals organized by the ACFAS – Association francophone pour le savoir, that will be held on May 4, 2017 at McGill University.
Jaber Shabanian, Pierre Sauriol, Navid Mostoufi, and Jamal Chaouki has recently published a research article in the Powder Technology. The performance of different approaches for the early detection of defluidization in a high temperature bubbling gas-solid fluidized bed and their robustness with respect to the changes in superficial gas velocity, operating temperature, and bed inventory were compared in this study. The results showed that the novel approach proposed by Shabanian et al. 2015 (Procedia Eng. 102 (2015) 1006-1015), which employs the idea of simultaneous monitoring of temperature and in-bed differential pressure signals, with the detection thresholds introduced by Shabanian et al. 2017 (Chem. Eng. J. 133 (2017) 144-156) provides the best performance.
Abstract of the article is provided below:
Identifying the onset of an agglomeration phenomenon at an early stage in processes utilizing gas-solid fluidized beds that operate under the influence of cohesive interparticle forces affords enough time to apply counteractive strategies and avoid a disastrous agglomeration of particles potentially leading to complete bed defluidization. In this paper, we compare the performance of different leading approaches proposed in the open literature for the advanced detection of defluidization. The approaches include the single-signal-monitoring of evolutions of total bed pressure drop, standard deviation of pressure signals, or -value from the attractor comparison analysis as well as the simultaneous-monitoring of temperature and in-bed differential pressure signals during the process. The results show that the simultaneous-monitoring of temperature and in-bed differential pressure signals provided the best prediction of the onset of agglomeration while it demonstrated the least sensitivity to the changes in gas velocity, operating temperature, and bed inventory.
Jaber Shabanian and Jamal Chaouki has recently published a review article in the Chemical Engineering Journal. This review addresses the effects of operating temperature and pressure and interparticle forces on the gas-solid fluidization of a wide spectrum of powders that behave like Geldart groups A, B, and D powders at ambient conditions.
Abstract of the article is provided below:
An in-depth examination of the hydrodynamics of gas-solid fluidized beds at high temperature and pressure is critical for their design and operation owing to the global trend of processing lower quality feedstocks, e.g., high ash content coal, biomass, and waste, in these units. Current knowledge on gas-solid fluidization, though, refers to ambient conditions and the hydrodynamic models based on these conditions by merely changing the gas properties, i.e., its density and viscosity, are generally employed to estimate the overall performance of gas-solid fluidized bed processes under extreme conditions. This strategy, however, overlooks possible modifications induced by the operating conditions on the structure and dynamics of fluidized particles, i.e., the level of interparticle forces. With the development of new processes adopting gas-solid fluidized beds under extreme conditions, a comprehensive review of the experimental and simulation studies of gas-solid fluidization at elevated temperatures and pressures and in the presence of interparticle forces is warranted. This review addresses the effects of temperature, pressure, and interparticle forces on the fluidization characteristics of gas-solid fluidized beds for a wide spectrum of particle systems, ranging from Geldart groups A, B, and D classifications, refer to the fluidization behavior at ambient conditions.
Jaber Shabanian, Pierre Sauriol, and Jamal Chaouki has recently published a research article in the Chemical Engineering Journal. A novel approach was introduced for the early detection of defluidization conditions in a bubbling gas-solid fluidized bed. The new approach benefits from its simplicity, effectiveness, and robustness with respect to the variation of influential operating parameters, i.e., bed temperature, superficial gas velocity, and bed inventory.
Below you can find the abstract:
This study presents a simple approach for the early detection of agglomeration in a bubbling gas-solid fluidized bed. This monitoring approach is based on the simultaneous measurements of local temperatures and the in-bed differential pressure drop from the well-stabilized section of the bed. Defluidization experiments (800–1000oC) showed that when a bubbling gas-solid fluidized bed approaches complete defluidization the average in-bed differential pressure drop progressively decreases from a reference value obtained under normal conditions while the temperature difference along the axis, particularly between a temperature reading right above the distributor plate and others at higher levels within the dense bed, simultaneously increases. This novel approach was thus proposed for the concurrent occurrence of these drifts to provide an opportune recognition of the onset of agglomeration in a bubbling gas-solid fluidized bed. The results demonstrated that it could effectively detect the defluidization condition minutes to hours before the complete defluidization state depending on the growth rate of agglomeration within the bed. Two pairs of detection thresholds for the timely recognition of agglomeration in bubbling fluidized beds of coarse silica sand particles were introduced according to the observations made in this study. The approach exhibited minimal sensitivity to variations in the superficial gas velocity (±10%), operating temperature (±100oC), and bed inventory (±20%) while both legs of the in-bed differential pressure transducer were well below the splash zone and above the jetting zone formed in the vicinity of the distributor plate.
Sherif Farag and Jamal Chaouki, in collaboration with researchers of Queen’s University, published a new research paper entitled “Impact of the Heating Mechanism on the Yield and Composition of Bio-Oil from Pyrolysis of Kraft Lignin” on the Journal of Biomass and Bioenergy.
Below, abstract of the paper is provided:
The aim of this work is to differentiate between the yield and composition of bio-oils obtained from microwave and conventional pyrolysis of kraft lignin. Four different conditions were performed, microwave and conventional pyrolysis with and without mixing the raw material with a strong microwave receptor. The key findings of this work include that applying microwaves in pyrolysis applications leads to preserving the structure of the obtained products, which consequently enhances the product selectivity. As a result, the liquid product from the pyrolysis of lignin contains 40% more chemicals, and 27% less water than that of the conventional pyrolysis. The impact of electromagnetic waves on the quantitative aspect is not considerable as the difference between the liquid yields from both techniques is slight. Increasing the heating rate and/or the residence time, particularly in conventional pyrolysis, makes secondary reactions play a vital role in decomposing and/or combining the obtained aromatic hydrocarbons.
Sepehr Hamzehlouia, doctoral student in chemical engineering, won the contest “Pitch-nous ta techno!” presented by Univalor, in collaboration with polymtl.
Mr. Hamzehlouia is working on a technique to improve the effectiveness of catalytic reactions for the production of syngas, under the supervision of professors Jamal Chaouki and Robert Legros. He won an award of $ 300 and the accompaniment of Univalor for the marketing of his technology.
The 5th international Congress on Green Process Engineering was held in Mont Tremblant, Quebec, Canada during June 19-24, 2016.
Professor Jamal Chaouki delivered a plenary speech entitled “Improving Resource Efficiency to Address Climate Change by Observing Nature” that was co-authored by Jocelyn Doucet, a former PEARL member.
Drs. Mohammad Latifi, Abdelmajid Rakib, Pierred Sauriol, Jaber Shabanian and Jamal Chaouki presented their research on “Co-Combustion of Coal and a ReEngineered Feedstock for Emissions Reduction”.
In collaboration with researchers of Laval University, Mohammad Latifi co-authored in publication of a research article entitled “Ionic-liquid Collectors for Rare-Earth Minerals Flotation—Case of Tetrabutylammonium Bis(2-ethylhexyl)-Phosphate for Monazite and Bastnäsite Recovery” on the Journal of Colloids and Surfaces A: Physicochemical and Engineering Aspects.
Below, abstract of the paper are provided:
Application of tetrabutylammonium bis(2-ethylhexyl)-phosphate ([N4444][DEHP]), a room temperature ionic liquid (IL), as an aqueous collector for flotation of model monazite and bastnäsite minerals was investigated through micro-flotation tests, zeta potential measurements, Fourier Transform Infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The ionic liquid was shown to have superior performance to float both model rare-earth (RE) minerals as compared with calcite, dolomite and quartz minerals as typical gangue minerals. Parallel to this, micro-flotation tests of a rare-earth ore containing bastnäsite and monazite minerals were found in line with [N4444][DEHP] stronger collecting power towards RE model minerals even outperforming hydroxamic acid-containing collectors. With regard to the mineral surface chemistry, zeta potential measurements, FTIR characterization and XPS analysis, it was established that [N4444][DEHP] uptake on bastnäsite and monazite surfaces was via chemisorption involving specifically the PO and PO groups of the IL anionic moiety. IL anionic and cationic interactions during RE mineral flotation were rationalized in terms of an inner synergistic pathway: IL anionic moiety chemisorbing on bastnäsite and monazite surfaces prompting uptake of cationic moiety via electrostatic attraction and/or via hydrophobic chain interactions of the cation alkyl chains with the chemisorbed IL anionic layer. Finally, for calcite as the most responsive among gangue minerals, the characterization techniques divulged the weaker IL-surface interactions. Hence, this investigation opens up new prospects for more selective ionic-liquid collectors to be used in the flotation of RE minerals.