10th international conference on gas-liquid and gas-liquid-solid reactor engineering preface

Following the success of the nine previous conferences on Gas–Liquid and Gas–Liquid–Solid reactor Engineering which were held at Columbus, OH, USA (1992), Cambridge, UK (1995), Kanagawa, Japan (1997), Delft, The Netherlands (1999), Melbourne, Australia (2001), Vancouver, Canada (2003), Strasbourg, France (2005), New Delhi, India (2007) and Montreal, Canada (2009) the tenth conference with the same theme is being held in Braga, Portugal, from 26 to 29 June 2011. This conference will cover all aspects of multiphase reactors related to progress made in the understanding, performance and operation of these reactors and will bring together scientists and engineers from universities and industry. The involvement of top researchers in Gas–Liquid and Gas–Liquid–Solid Reactor Engineering, the high quality of the papers presented and the line of continuity that has been guaranteed by the leadership of Prof. L.S. Fan of Ohio State University and the other members of the International Scientific Committee has made GLS a leading conference in Chemical Engineering. GLS has been held at regular intervals, every two years and in order to attract professionals across the globe, the venue of the GLS conference is shifted in a thoughtful manner amongst the continents. This conference has become an important meeting point for the exchange of views among scientists and engineers in one of the most important and complex issues in chemical engineering science and practice. The organizing committee is very pleased to be associated with Elsevier to have, as in most of the previous GLS editions, the proceedings of GLS10 published in Chemical Engineering Science (CES). As a result of a strict peer review process aiming at keeping with the highest standards of the journal, the GLS10 CES special issue includes a total of 39 papers, selected from the 150 Abstracts that were submitted to GLS10. Our sincere acknowledgments are due to Professor Anton P.J. Middelberg, the Executive Editor of CES, for his cooperation throughout the reviewing process. Also, we would like to express our gratitude to all the reviewers that made possible a timely publication of this special issue. Thanks are due to Genevieve Green from Elsevier for the excellent management of this special issue publication. Finally, it is our pleasure to dedicate this GLS10 CES special issue to Professor John Davidson as a tribute to his pioneering work and extraordinary contributions to Gas–Liquid and Gas–Liquid–Solid Reactor Engineering and to Chemical Engineering

Parametric Study of Experimental and CFD Simulation Based Hydrodynamics and Mass Transfer of Rotating Packed Bed: A Review

The emission of CO2 into the atmosphere is one of the major causes of the greenhouse effect, which has a devastating effect on the environment and human health. Therefore, the reduction of CO2 emission in high concentration is essential. The Rotating Packed Bed (RPB) reactor has gained a lot of attention in post-combustion CO2 capture due to its excellent rate of mass transfer and capture efficiency. To better understand the mechanisms underlying the process and ensure optimal design of RPB for CO2 absorption, elucidating its hydrodynamics is of paramount importance. Experimental investigations have been made in the past to study the hydrodynamics of RPB using advanced imaging and instrumental setups such as sensors and actuators. The employments of such instruments are still challenging due to the difficulties in their installation and placement in the RPB owing to the complex engineering design of the RPB. The hydrodynamics of the RPB can be affected by various operational parameters. However, all of them cannot be evaluated using a single instrumental setup. Therefore, the experimental setups generally result in a partial understanding of the flow behavior in the RPB. The cons and pros of experimental methods are reported and critically discussed in this paper. Computational Fluid Dynamics (CFD), on the other hand, is a powerful tool to visually understand the insights of the flow behavior in the RPB with accurate prediction. Moreover, the different multiphase and turbulence models employed to study the hydrodynamics of RPB have also been reviewed in-depth along with the advantages and disadvantages of each model. The models such as Sliding Mesh Model (SMM) and rotating reference frame model have been adopted for investigating the hydrodynamics of the RPB. The current research gaps and future research recommendations are also presented in this paper which can contribute to fill the existing gap for the CFD analysis of Rotating Packed Bed (RPB) for CO2 absorption

Concurrent inhibition of oncogenic and wild-type RAS-GTP for cancer therapy

RAS oncogenes (collectively NRAS, HRAS and especially KRAS) are among the most frequently mutated genes in cancer, with common driver mutations occurring at codons 12, 13 and 611. Small molecule inhibitors of the KRAS(G12C) oncoprotein have demonstrated clinical efficacy in patients with multiple cancer types and have led to regulatory approvals for the treatment of non-small cell lung cancer2,3. Nevertheless, KRASG12C mutations account for only around 15% of KRAS-mutated cancers4,5, and there are no approved KRAS inhibitors for the majority of patients with tumours containing other common KRAS mutations. Here we describe RMC-7977, a reversible, tri-complex RAS inhibitor with broad-spectrum activity for the active state of both mutant and wild-type KRAS, NRAS and HRAS variants (a RAS(ON) multi-selective inhibitor). Preclinically, RMC-7977 demonstrated potent activity against RAS-addicted tumours carrying various RAS genotypes, particularly against cancer models with KRAS codon 12 mutations (KRASG12X). Treatment with RMC-7977 led to tumour regression and was well tolerated in diverse RAS-addicted preclinical cancer models. Additionally, RMC-7977 inhibited the growth of KRASG12C cancer models that are resistant to KRAS(G12C) inhibitors owing to restoration of RAS pathway signalling. Thus, RAS(ON) multi-selective inhibitors can target multiple oncogenic and wild-type RAS isoforms and have the potential to treat a wide range of RAS-addicted cancers with high unmet clinical need. A related RAS(ON) multi-selective inhibitor, RMC-6236, is currently under clinical evaluation in patients with KRAS-mutant solid tumours (ClinicalTrials.gov identifier: NCT05379985).J.E. Klomp is funded by National Cancer Institute grants T32CA009156, F32CA239328 and K99CA276700, and American Cancer Society grant PF-20-069. P.L. is supported in part by the NIH/NCI (1R01CA23074501, 1R01CA23026701A1 and 1R01CA279264-01), The Pew Charitable Trusts, the Damon Runyon Cancer Research Foundation, and the Pershing Square Sohn Cancer Research Alliance. P.L. is also supported by the Josie Robertson Investigator Program and the Support Grant-Core Grant program (P30 CA008748) at Memorial Sloan Kettering Cancer Center. D.S. is funded by AECC Excellence Program 2022 (EPAEC222641CICS). A.J.A. has research funding from Bristol Myers Squibb, Deerfield, Eli Lilly, Mirati Therapeutics, Novartis, Novo Ventures, Revolution Medicines and Syros Pharmaceuticals. A.M.W. was supported by a grant from the NCI (K22CA276632-01). C.J.D. has received research funding support from Deciphera Pharmaceuticals, Mirati Therapeutics, Reactive Biosciences, Revolution Medicines, and SpringWorks Therapeutics, the National Cancer Institute (P50CA257911 and R35CA232113), Department of Defense (W81XWH2110692), and Pancreatic Cancer Action Network (22-WG-DERB). C.A. is funded by grants from the Giovanni Armenise–Harvard Foundation, the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 101001288) and AIRC under IG 2021–ID. 25737 project.Peer reviewe

CFD study: Effect of pulsating flow on gas-solid hydrodynamics in FCC riser

Gas-solid flow in a fluid catalytic cracking (FCC) riser exhibits poor mixing in the form of a core-annulus flow pattern and a dense bottom/dilute top distribution of solids. To enhance gas-solid mixing, studies on dense fluidized beds have suggested using a pulsating flow of gas. The present study investigates the effect of pulsating flow on gas-solid hydrodynamics inside the FCC riser employing computational fluid dynamics. Two flow conditions are investigated: a cold flow of air-FCC catalyst in a pilot-scale riser and a reactive flow in an industrial-scale FCC riser. In the cold-flow riser, pulsating flows cause the slug flow of solids and thus increase the average solid accumulation in the flow domain and solid segregation towards the wall. In the industrial FCC riser, pulsating flows produce radial profiles that are more homogeneous. Pulsating flows further improve the conversion and yield in the initial few metres of height. At 7. m, the conversion from pulsating flow is 59%, compared with 44% in without pulsating flow. The results and analysis presented here will help optimize flow conditions in the circulating fluidized bed riser, in not only FCC but also applications such as fast pyrolysis and combustion

Simulations of low and high solid flux risers using energy minimization multiscale model: Effect of cluster diameter correlations

Accounting an effect of cluster formation on hydrodynamics of FCC riser is critical, and the energy minimization multiscale (EMMS) model provides a framework to capture clusters by using a cluster diameter correlation. In this study, different cluster diameter correlations (CDC) were used with the EMMS model to calculate structure-based drag coefficients, and these drag coefficients were then used to carry out CFD simulations of 2D riser with both low and high flux flows of FCC particles. Initial simulations using the EMMS and Gidaspow drag model showed that the EMMS model could capture an S-shape axial profile with a dense bottom and dilute top with showing qualitative agreements with experimental data. The EMMS drag largely depends on a cluster diameter correlation. Therefore, simulations were performed using the EMMS drag coefficients calculated from different CDCs i.e. (i) Chavan, (1984), (ii) Harris et al., (2002) and (iii) Subbarao, (2010). It was found that the cluster diameter correlations had considerable effect on the calculated drag and hydrodynamic predictions. While no universal agreement was observed between the hydrodynamic prediction from different CDCs and experimental data. Thus, it was concluded that a combination of CDCs in different ranges of voidages can be useful to achieve qualitative agreements between the hydrodynamics predictions and experimental data, and this study can be used to identify possible this combination of the CDCs for a given flow system

Anesthetic management for renal transplant in patients with grade III diastolic dysfunction: case reports

Abstract Background Left ventricular diastolic dysfunction is frequently noticed in patients with multiple co-morbidities. Echocardiography is used to determine the presence of diastolic dysfunction and to grade its severity. In left ventricular diastolic dysfunction, the ventricular diastolic distensibility, filling, or relaxation is abnormal; however, the left ventricular ejection fraction may be normal or decreased. Case presentation We present anesthetic management of two patients with diastolic dysfunction grade III for renal transplant. During declamping in renal transplant, high central venous pressures are required for adequate perfusion of the transplanted kidney. In the operation theater standard monitors including NIBP, SpO2 and five lead ECG were attached. An arterial line (radial) and central line (right internal jugular) were established for IBP and CVP monitoring. Infusions of furosemide and dopamine were started. Nitrogycerine and milrinone infusions were prepared but were not required intraoperatively. Both the patients were extubated at the end of surgery. Conclusions Increased incidence of major adverse cardiovascular events has been reported in surgical patients having grade III diastolic dysfunction. Hemodynamic instability and fluid overload in this set of patients are known to generate pulmonary edema

Effect of baffles on performance of fluid catalytic cracking riser

Increasing demand of automobile fuel and a need to process heavier crude oil makes it imperative to find improvements to the design of existing fluid catalytic cracking (FCC) units. Several modifications to the design of the riser section of FCC units have been suggested in previous studies including: improved feed nozzle designs, multiple nozzle configurations, internal baffles, and novel two-stage-riser systems. In this study, we investigate the effects of baffles on the performance of FCC risers using computational fluid dynamics simulations. In this study, predictions from a basis model (without baffles) are compared with those from four different configurations including: (i) 5-cm baffles at 5-m spacing, (ii) 7.5-cm baffles at 5-m spacing, (iii) 10-cm baffles with 5-m spacing, (iv) 10-cm baffles at 2.5-m spacing, and (v) 10-cm baffles at 1-m spacing. The baffles force the catalyst away from walls toward the center of the riser, enhancing the radial dispersion of the catalyst and the heat transfer inside the riser. The use of longer baffles and smaller spacings further increases the dispersion, yielding more homogeneous radial profiles. The changes in the radial dispersion result in variations in the conversion, yields, and pressure drops. The baffles increase conversion of vacuum gas oil (VGO) and the yield of gasoline. However, the simulations showed that longer baffles and a larger number of baffles did not always give a higher yield or higher conversion. Among the simulated configurations, the 5-cm baffles at 5-m spacing gave the highest conversion of VGO, whereas the 10-cm baffles at 1-m spacing resulted in the highest yield of the gasoline. Thus, rational optimization of baffle configurations is required to achieve optimal performance

Effect of closure models on Eulerian-Eulerian gas-solid flow predictions in riser

Gas–solid flows in a riser have often been investigated by using the Eulerian–Eulerian (E–E) model. The E–E model consists of mass and momentum conservations equations, along with equations for boundary conditions and several closure relations that dictate flow predictions. Despite several previous studies, there is still ambiguity in the selection of appropriate closure laws and boundary conditions for a given flow condition. In this study, the effects of specularity coefficients of partial-slip wall boundary condition, gas phase viscous stress models and interphase drag models on flow predictions from the E–E model have been investigated for both low (14.3 kg/m2 s) and high (489 kg/m2 s) solids flux riser flows. A lower specularity coefficient of 0.0001 gives a reasonable agreement between the predicted axial profiles and experimental data; however, in a dense bottom region (at a height of 3.5 m) of low solids flux riser, a higher specularity coefficient of 0.1 shows a core–annulus radial profile as observed in the experiments. Both laminar and k-ε dispersed turbulent models are able to give qualitative predictions of the experimental values, whereas predictions from k-ε per-phase turbulent model result in wide discrepancies. For both the solids flux conditions, the conventional Gidaspow drag model fails to predict the experimental data; whereas the axial and radial profiles from both the EMMS and corrected-EMMS models are in reasonable agreement with the experimental data.Only a minor difference between the values predicted by the EMMS and corrected-EMMS is observed as the drag values calculated from the both drag models are similar for a range of solid volume fraction from 0 to 0.15. While the laminar or k-ε dispersed turbulent model and EMMS or corrected-EMMS drag model are found to be more appropriate for riser simulations with both flow conditions, the selection of the specularity coefficient requires more investigations at various flow conditions