ACS Engineering Au最新文献

{"title":"Emerging Trends of Computational Chemistry and Molecular Modeling in Froth Flotation: A Review","authors":"Abolfazl Alizadeh Sahraei,&nbsp;Dariush Azizi,&nbsp;Abdol Hadi Mokarizadeh,&nbsp;Daria Camilla Boffito* and Faïçal Larachi*,&nbsp;","doi":"10.1021/acsengineeringau.2c00053","DOIUrl":"10.1021/acsengineeringau.2c00053","url":null,"abstract":"<p >Froth flotation is the most versatile process in mineral beneficiation, extensively used to concentrate a wide range of minerals. This process comprises mixtures of more or less liberated minerals, water, air, and various chemical reagents, involving a series of intermingled multiphase physical and chemical phenomena in the aqueous environment. Today’s main challenge facing the froth flotation process is to gain atomic-level insights into the properties of its inherent phenomena governing the process performance. While it is often challenging to determine these phenomena via trial-and-error experimentations, molecular modeling approaches not only elicit a deeper understanding of froth flotation but can also assist experimental studies in saving time and budget. Thanks to the rapid development of computer science and advances in high-performance computing (HPC) infrastructures, theoretical/computational chemistry has now matured enough to successfully and gainfully apply to tackle the challenges of complex systems. In mineral processing, however, advanced applications of computational chemistry are increasingly gaining ground and demonstrating merit in addressing these challenges. Accordingly, this contribution aims to encourage mineral scientists, especially those interested in rational reagent design, to become familiarized with the necessary concepts of molecular modeling and to apply similar strategies when studying and tailoring properties at the molecular level. This review also strives to deliver the state-of-the-art integration and application of molecular modeling in froth flotation studies to assist either active researchers in this field to disclose new directions for future research or newcomers to the field to initiate innovative works.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":"3 3","pages":"128–164"},"PeriodicalIF":0.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/23/16/eg2c00053.PMC10288516.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9714560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrometallurgical Processing of Chalcopyrite by Attrition-Aided Leaching","authors":"Amine Dakkoune,&nbsp;Florent Bourgeois,&nbsp;Adeline Po,&nbsp;Catherine Joulian,&nbsp;Agathe Hubau,&nbsp;Solène Touzé,&nbsp;Carine Julcour*,&nbsp;Anne-Gwénaëlle Guezennec and Laurent Cassayre,&nbsp;","doi":"10.1021/acsengineeringau.2c00051","DOIUrl":"10.1021/acsengineeringau.2c00051","url":null,"abstract":"<p >We report the investigation of a chalcopyrite leaching process that implements millimeter-sized glass beads that are stirred in the leach reactor to combine particle grinding, mechanical activation, and surface removal of reaction products. The paper focuses on demonstrating the impact of the so-called attrition-leaching phenomenon on the leaching rate of a chalcopyrite concentrate and provides a first understanding of the underlying mechanisms. For this purpose, we have compared the copper leaching yield for different configurations under controlled chemical conditions (1 kg of glass beads and 84 g of chalcopyrite concentrate in 2.5 L of H₂SO₄-H₂O solution, pH = 1.3, <i>E</i>_h = 700 mV vs SHE, and <i>T</i> = 42 °C). On top of elemental analysis of the leach solution with time, we provide a full characterization of the solid residue based on X-ray diffraction, elemental analysis, and sulfur speciation. We demonstrate that glass beads led to a remarkable enhancement of the leaching rate in conditions where particles were already passivated by simple leaching and even when large amounts of solid products (elemental sulfur and jarosite) were present. An in-depth evaluation of particle size distribution showed that particle breakage occurred during a rather short time (a few hours) at the beginning of the runs, transforming the initial particles with <i>d</i>_4/3 = 30 μm to finer particles with <i>d</i>_4/3 = 15 μm. Then, particle breakage almost stopped, while an attrition phenomenon was evidenced, inducing the formation of very fine particles (&lt;1 μm) and aggregates concomitantly with copper leaching.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":"3 3","pages":"195–209"},"PeriodicalIF":0.0,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.2c00051","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41296529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Production of Acetaldehyde via Oxidative Dehydrogenation of Ethanol in a Chemical Looping Setup","authors":"Joseph C. Gebers*,&nbsp;Abu Farhan Bin Abu Kasim,&nbsp;George J. Fulham,&nbsp;Kien Yi Kwong and Ewa J. Marek*,&nbsp;","doi":"10.1021/acsengineeringau.2c00052","DOIUrl":"10.1021/acsengineeringau.2c00052","url":null,"abstract":"<p >A novel chemical looping (CL) process was demonstrated to produce acetaldehyde (AA) via oxidative dehydrogenation (ODH) of ethanol. Here, the ODH of ethanol takes place in the absence of a gaseous oxygen stream; instead, oxygen is supplied from a metal oxide, an active support for an ODH catalyst. The support material reduces as the reaction takes place and needs to be regenerated in air in a separate step, resulting in a CL process. Here, strontium ferrite perovskite (SrFeO_3−δ) was used as the active support, with both silver and copper as the ODH catalysts. The performance of Ag/SrFeO_3−δ and Cu/SrFeO_3−δ was investigated in a packed bed reactor, operated at temperatures from 200 to 270 ^°C and a gas hourly space velocity of 9600 h^–1. The CL capability to produce AA was then compared to the performance of bare SrFeO_3−δ (no catalysts) and materials comprising a catalyst on an inert support, Cu or Ag on Al₂O₃. The Ag/Al₂O₃ catalyst was completely inactive in the absence of air, confirming that oxygen supplied from the support is required to oxidize ethanol to AA and water, while Cu/Al₂O₃ gradually got covered in coke, indicating cracking of ethanol. The bare SrFeO_3−δ achieved a similar selectivity to AA as Ag/SrFeO_3−δ but at a greatly reduced activity. For the best performing catalyst, Ag/SrFeO_3−δ, the obtained selectivity to AA reached 92–98% at yields of up to 70%, comparable to the incumbent Veba-Chemie process for ethanol ODH, but at around 250 ^°C lower temperature. The CL-ODH setup was operated at high effective production times (i.e., the time spent producing AA to the time spent regenerating SrFeO_3−δ). In the investigated configuration with 2 g of the CLC catalyst and 200 mL/min feed flowrate ∼5.8 vol % ethanol, only three reactors would be required for the pseudo-continuous production of AA via CL-ODH.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":"3 3","pages":"184–194"},"PeriodicalIF":0.0,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.2c00052","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9714557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Welcome to Volume 3 of ACS Engineering Au","authors":"Vivek V. Ranade*,&nbsp; and ,&nbsp;Linda J. Broadbelt*,&nbsp;","doi":"10.1021/acsengineeringau.3c00001","DOIUrl":"10.1021/acsengineeringau.3c00001","url":null,"abstract":"","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":"3 1","pages":"1–2"},"PeriodicalIF":0.0,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.3c00001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43957572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermodynamics, Kinetics, Morphology, and Raman studies for sH Hydrate of Methane and Cyclooctane","authors":"Namrata Gaikwad,&nbsp;Hyunho Kim,&nbsp;Gaurav Bhattacharjee,&nbsp;Jitendra S Sangwai,&nbsp;Rajnish Kumar* and Praveen Linga*,&nbsp;","doi":"10.1021/acsengineeringau.2c00050","DOIUrl":"10.1021/acsengineeringau.2c00050","url":null,"abstract":"<p >Natural gas is expected to be the major energy source in the near future, and storing it in the form of gas hydrate is a safe, clean, and economical approach. However, required thermodynamic conditions and slow kinetics are the key challenges that need to address for process viability. This study involves an experimental investigation of methane and cyclooctane sH hydrate formation for possible applications in gas storage using thermodynamics, kinetics, morphology, and Raman analysis. The hydrate formation is carried out at such thermodynamic conditions where only sH hydrate would form. The four-phase (L_w-L_HC-H-V) sH hydrate equilibrium is studied for the methane and cyclooctane system via dissociation along the phase boundary method which is a robust method as it delivers a greater number of equilibrium data points in a single experimental run compared to other available methods. The sH hydrate formation helps in lowering the equilibrium conditions compared with sI hydrate formation. The slow sH hydrate formation kinetics can be improved by using low tryptophan concentrations. In this work, 0.1 wt % is the optimum tryptophan concentration as the gas uptake, and the hydrate formation rate is found to be the highest compared to 0.01, 0.05, and 1 wt % tryptophan concentrations. Here, we also visually investigate the sH hydrate formation and observed that the hydrate formation occurs below the interface for the system with no tryptophan; however, hydrate formation occurrence above the interface increases with an increase in the tryptophan concentration. The increase in the hydrate formation could be dedicated to the increased gas uptake due to the increasingly porous nature of hydrate formation. The Raman analysis confirmed the presence of methane and cyclooctane in sH hydrate cages. The higher intensity of the peaks using tryptophan additionally confirms the higher hydrate formation compared to the system with no tryptophan.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":"3 3","pages":"173–183"},"PeriodicalIF":0.0,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.2c00050","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46868608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solid Phase Macromixing Study in a Pilot-Scale Geldart Group B Circulating Fluidized Bed Riser Using Single Particle RTD and RPT Measurements","authors":"Trilokpati Tribedi,&nbsp;Pankaj Tiwari,&nbsp;Harish Jagat Pant and Rajesh Kumar Upadhyay*,&nbsp;","doi":"10.1021/acsengineeringau.2c00049","DOIUrl":"10.1021/acsengineeringau.2c00049","url":null,"abstract":"<p >Solid flow in a Geldart’s group B circulating fluidized bed (CFB) riser is complex, and it exhibits backflow and recirculation in the riser. A single radioactive tracer particle is used to measure the overall and sectional residence time distribution in a CFB riser at a gas velocity of 7.6–9.2 m/s and a solid flux of 100–200 kg/m²s. At the same time, radioactive particle tracking (RPT) data are used to measure the trajectories of the tracer particle and its length distribution at the bottom and middle sections of the riser. Both residence time distribution (RTD) and trajectory length distribution data obtained from RPT and RTD experiments are processed and compared. Results show that the bottom section has higher back mixing than the middle section. The results also show that back mixing in both the sections reduces with an increase in the gas inlet velocity and reduces marginally with an increase in the solid flux. Results confirm that RPT and RTD data are highly correlated and can be used with the same accuracy to quantify the macromixing behavior of any process vessel/reactor.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":"3 3","pages":"165–172"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.2c00049","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44105459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Overcoming the Entropy Penalty of Direct Air Capture for Efficient Gigatonne Removal of Carbon Dioxide","authors":"Jimmy K. Soeherman,&nbsp;Andrew J. Jones and Paul J. Dauenhauer*,&nbsp;","doi":"10.1021/acsengineeringau.2c00043","DOIUrl":"10.1021/acsengineeringau.2c00043","url":null,"abstract":"<p >Atmospheric carbon poses an existential threat to civilization via global climate change. Hundreds of gigatonnes of carbon dioxide must be removed from earth’s atmosphere in the next three decades, necessitating a low-cost, energy-efficient process to extract low concentrations of carbon dioxide for conversion to a stable material permanently stored for thousands of years. In this work, the challenge of removing gigatonnes of CO₂ is described via the scale of effort and the thermodynamics of collecting and reducing this diffuse chemical, the accumulation of which imparts a substantial entropy penalty on any atmospheric carbon capture process. The methods of CO₂ reduction combined with upstream direct air capture (DAC) including absorption, membrane separation, and adsorption are compared with biomass torrefaction and permanent burial (BTB). A Monte Carlo model assesses the mass, energy, and economics of the full process of biomass torrefaction from biomass collection and transport to stable carbon burial to determine that 95% of scenarios could remove carbon for less than $200 per CO₂-tonne-equivalent. Torrefied carbon is further discussed for its long-term stability and availability at the scale required to substantially mitigate the threat of climate change.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":"3 2","pages":"114–127"},"PeriodicalIF":0.0,"publicationDate":"2023-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.2c00043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44726064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Power Consumption and Fluid Mixing in a Scale-Down Geometry of a Stirred Digester for Biogas Production","authors":"Federico Alberini,&nbsp;Francesco Maluta,&nbsp;Alessandro Paglianti and Giuseppina Montante*,&nbsp;","doi":"10.1021/acsengineeringau.2c00047","DOIUrl":"10.1021/acsengineeringau.2c00047","url":null,"abstract":"<p >A unconventional stirred tank of geometry typically adopted for the production of biogas is experimentally investigated with pseudo-plastic model fluids. The apparent viscosities of the fluids, based on the Metzner–Otto method, are in the range of 39–264 mPa·s, resulting in a range of rotational Reynolds number equal to 17–648. The power consumption of the three top-entering agitators is measured by a strain gauge technique, and the power number curve is obtained in the full range of flow regimes, going from laminar to fully turbulent conditions. The flow field measured by particle image velocimetry allows us to observe the fluid circulation patterns and their variations in different operative conditions. The measurements reveal relatively low axial and radial velocities, especially toward the bottom of the tank, that may hinder solid feedstock suspension and subsequent biogas production. Significant changes in the flow patterns are observed with small variations in the impeller speed and the mixture viscosity. The homogenization dynamics of a tracer obtained by planar laser-induced fluorescence leads us to estimate the dimensionless mixing time, a trend similar to that observed for conventional stirred vessel geometries. The detailed fluid dynamics information collected by a combination of different techniques can contribute to optimize the energy requirement and to avoid failure of the biogas production due to poor fluid mixing.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":"3 2","pages":"102–113"},"PeriodicalIF":0.0,"publicationDate":"2023-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.2c00047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44344493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical Recycling of Used PET by Glycolysis Using Niobia-Based Catalysts","authors":"Shadi Shirazimoghaddam,&nbsp;Ihsan Amin,&nbsp;Jimmy A Faria Albanese and N. Raveendran Shiju*,&nbsp;","doi":"10.1021/acsengineeringau.2c00029","DOIUrl":"10.1021/acsengineeringau.2c00029","url":null,"abstract":"<p >Plastic production has steadily increased worldwide at a staggering pace. The polymer industry is, unfortunately, C-intensive, and accumulation of plastics in the environment has become a major issue. Plastic waste valorization into fresh monomers for production of virgin plastics can reduce both the consumption of fossil feedstocks and the environmental pollution, making the plastic economy more sustainable. Recently, the chemical recycling of plastics has been studied as an innovative solution to achieve a fully sustainable cycle. In this way, plastics are depolymerized to their monomers or/and oligomers appropriate for repolymerization, closing the loop. In this work, PET was depolymerized to its bis(2-hydroxyethyl) terephthalate (BHET) monomer via glycolysis, using ethylene glycol (EG) in the presence of niobia-based catalysts. Using a sulfated niobia catalyst treated at 573 K, we obtained 100% conversion of PET and 85% yield toward BHET at 195 °C in 220 min. This approach allows recycling of the PET at reasonable conditions using an inexpensive and nontoxic material as a catalyst.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":"3 1","pages":"37–44"},"PeriodicalIF":0.0,"publicationDate":"2023-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsengineeringau.2c00029","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10769058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine Learning Predictions of Oil Yields Obtained by Plastic Pyrolysis and Application to Thermodynamic Analysis","authors":"Elizabeth R. Belden,&nbsp;Matthew Rando,&nbsp;Owen G. Ferrara,&nbsp;Eric T. Himebaugh,&nbsp;Christopher A. Skangos,&nbsp;Nikolaos K. Kazantzis,&nbsp;Randy C. Paffenroth and Michael T. Timko*,&nbsp;","doi":"10.1021/acsengineeringau.2c00038","DOIUrl":"10.1021/acsengineeringau.2c00038","url":null,"abstract":"<p >Chemical recycling via thermal processes such as pyrolysis is a potentially viable way to convert mixed streams of waste plastics into usable fuels and chemicals. Unfortunately, experimentally measuring product yields for real waste streams can be time- and cost-prohibitive, and the yields are very sensitive to feed composition, especially for certain types of plastics like poly(ethylene terephthalate) (PET) and polyvinyl chloride (PVC). Models capable of predicting yields and conversion from feed composition and reaction conditions have potential as tools to prioritize resources to the most promising plastic streams and to evaluate potential preseparation strategies to improve yields. In this study, a data set consisting of 325 data points for pyrolysis of plastic feeds was collected from the open literature. The data set was divided into training and test sub data sets; the training data were used to optimize the seven different machine learning regression methods, and the testing data were used to evaluate the accuracy of the resulting models. Of the seven types of models, eXtreme Gradient Boosting (XGBoost) predicted the oil yield of the test set with the highest accuracy, corresponding to a mean absolute error (MAE) value of 9.1%. The optimized XGBoost model was then used to predict the oil yields from real waste compositions found in Municipal Recycling Facilities (MRFs) and the Rhine River. The dependence of oil yields on composition was evaluated, and strategies for removing PET and PVC were assessed as examples of how to use the model. Thermodynamic analysis of a pyrolysis system capable of achieving oil yields predicted using the machine-learned model showed that pyrolysis of Rhine River plastics should be net exergy producing under most reasonable conditions.</p>","PeriodicalId":29804,"journal":{"name":"ACS Engineering Au","volume":"3 2","pages":"91–101"},"PeriodicalIF":0.0,"publicationDate":"2022-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/91/0e/eg2c00038.PMC10119934.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9447845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}