查看更多>>摘要：The current scheme of bioethanol production generally involves pretreatment, enzymatic hydrolysis and fermentation. After pretreatment, extensive washing is usually applied prior to enzymatic hydrolysis. This study investigates the potential of eliminating washing step in glucose recovery and ethanol production scheme when DES pretreatment is applied. The feasibility of DES synthesized using choline-chloride with citric acid (ChCl-CA), glycerol (ChCl-Gly), urea (ChCl-Urea) and malonic acid (ChCl-MA) were investigated in pretreating sugarcane bagasse. The pretreatment condition of the best performed DES was then optimized. Subsequently, glucose recovery and bioethanol production using washed and unwashed DES-pretreated bagasse were compared. Results show that ChCl-MA is the most suitable DES to pretreat sugarcane bagasse due to high sugar recovery while having low sugar loss during the process. The pretreatment was best conducted at 130 degrees C, 3.2 h with 4% solid loading. The maximum amount of glucose recovered after 48 h of enzymatic hydrolysis from both washed and unwashed pretreated substrate was insignificantly different. Bioethanol obtained from unwashed pretreated substrate was slightly higher (5.2 g/L) compared to washed substrate (4.9 g/L). This study suggests that the application of recyclable DES in pretreatment, alongside with the potential elimination of washing could improve the current bioethanol production scheme. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：This study explores the process intensification techniques and process control strategies on the product properties optimization. a-PABA, a long needle-like shape, can cause problems for the downstream processing. This study proposes ultrasound technique, supercooling control (SSC), and temperature cycling (TC) technologies to optimize the morphology and crystal size distribution of a-PABA. Firstly, the solubility and metastable zone of a-PABA in ethanol solvent are measured to determine the operational range. Next, the concentration calibration model is established to correlate the solubility with the ATR-FTIR intensity and temperature qualitatively. Furthermore, the process improvement techniques and control strategies are introduced to optimize the products. The ultrasound intensification contributes to produce the uniform crystal seeds. The SSC is benefit for the crystal growth, and can reduce the L/D ratio of the crystal product. While, TC is an efficient tool to eliminate the fine crystals. Moreover, the combination of ultrasound, SSC, and TC technology can show a significant improvement on the product particle aspects. The L/D ratio, crystal size, crystal morphology can show different degree of improvement under the combination techniques. At last, the outlook and perspectives on the process analytical technology are developed.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：This paper investigated the effect of the surface roughness (0.3 mu m, 1.1 mu m, 2.5 mu m, and 4.5 mu m) on the oil-gas separation efficiency. Through spraying the oil-gas mixture onto the vertical wall, the droplets impingement in inertial separators was imitated. The impact separation efficiency on a wall was calculated by comparing the volume of the collected oil flowing down from the wall with the volume of the impinging oil. Experiments were conducted three different impingement conditions. The impinging velocity and droplets size distributions on the impingement surface were characterized by the Malvern particle size analyzer and the particle image velocimetry (PIV) technique, respectively. The droplets impinging velocities varied in the range of 3-5 m/s, and the Sauter mean diameter was observed around 40 mu m. The collecting process can be divided into the initial stage and the steady stage according to the film flow state. It was found that the surface roughness has both advantages and disadvantages effect on the film flow. These two opposite effects are of different importance at different roughness levels. Under the studied impingement conditions, the separation efficiency was all above 80%, and the surface of the middle roughness (1.1-2.5 mu m) performed better than the smoothest 0.3 mu m surface and the roughest 4.5 mu m surface. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
Shehab, ShazaLinke, PatrickAl-Mohannadi, Dhabia M.
13页
查看更多>>摘要：Environmental concerns and depleting resources motivate economies to become more circular and encourage engineers to re-consider plant design by enhancing internal integration. This can be achieved by designing an eco-industrial park (EIP), in which a cluster of plants are synergistically integrated for mass and energy resources. Deciding which plants to include in the cluster determines its overall performance. In terms of economic performance, this is especially challenging as raw materials, products, and utility prices continuously fluctuate on the market, which results in the overall profit of a cluster becoming variable and imposes an investment risk to consider in decision making. In this study, Modern Portfolio Theory (MPT) is adopted to guide the selection of plants to be included in a process investment portfolio, considering both integrated (clusters) and non-integrated process plants or clusters. While integrated clusters typically enable improved returns through savings of energy and mass inputs over individual, stand-alone plants, their coupling may affect variability, and therefore, the risk dimension of portfolio construction. An MPT approach is proposed, which extends a recently presented MPT approach for stand-alone plant portfolio selection to consider optimally integrated clusters of plants, which are synthesized using an optimal design method that simultaneously considers all energy and material resources of a cluster. The MPT approach determines the process plant portfolios that are most attractive for investment from a risk-return perspective and the optimum capital distribution among portfolio constituents. A case study of six plants is presented to illustrate the MPT approach. The findings show that optimal risk-return portfolios do not consist of only integrated clusters of plants (EIPs) but are often complemented by stand-alone plants contributing to portfolio stability.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Aqueous ammonia has been widely applied to carbon dioxide capture thanks to its strong absorption capacity and low energy consumption, but the easily occurring ammonia escape may result in an additional environmental pollution. In this work, the aqueous ammonia with the Cr3+ or Ni2+ mixed at low temperatures is proposed and experimentally investigated to inhibit the ammonia escape and enhance carbon dioxide absorption. By taking the total ammonia escape, carbon dioxide absorption capacity and ammonia escape per unit carbon dioxide absorption as evaluation criteria, the effects of Ni2+ and Cr3+ on ammonia escape are compared. The results show that the increased reaction temperature and ammonia concentration result in the aggregated ammonia escape. The ammonia slip gets reduced but the carbon dioxide absorption is slightly affected with the Ni2+ and Cr3+ used due to the complex reaction between the metal ions and free ammonia. The additive of Ni2+ is basically superior to Cr3+ in restraining the ammonia escape, that the maximum inhibition efficiency of Ni2+ is 50.5% while Cr3+ is only 39.9%. By using additives, the reaction temperature can be raised to reduce the energy consumption of carbon dioxide absorption. It is recommended to adopt the chilled ammonia with additives for the carbon dioxide absorption by ammonia solution. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Adsorbent performance evaluation metrics such as selectivity and regenerability that can be computed from the results of molecular simulations are widely used to identify the most promising metal organic frameworks (MOF) for separation of CO2/N-2 mixture. Parasitic energy is recently offered to rank the MOFs for comparing the cost-effectiveness of an adsorption-based CO2/N-2 separation process. In this work, we performed Grand Canonical Monte Carlo simulations for 1661 MOFs to compute CO2/N-2 mixture adsorption data and then calculated selectivity, working capacity, adsorbent performance score (APS), regenerability (R%) of MOFs and parasitic energy. MOFs were ranked following two different approaches, one based on a combination of APS and R%, the other based on parasitic energy. Results showed that many MOFs are common in the top 100 adsorbents list of the two approaches, but the rankings of MOFs significantly differ since materials offering a low parasitic energy do not necessarily have a high R%. These results will provide important insights into the ranking of large number of MOFs based on different performance metrics for efficient identification of the most promising adsorbents for flue gas separation. (C) 2022 The Author(s). Published by Elsevier Ltd on behalf of Institution of Chemical Engineers.
查看更多>>摘要：This study focuses on computational fluid dynamics (CFD) modelling of the air entrainment phenomena in water columns which are commonly used in processing plants. The CFD model is first validated against experimental data. Then, a comprehensive set of CFD simulations are conducted to understand the effect of inlet jet velocity, nozzle diameter, tank diameter, and tank height on the bubble formation. Three main patterns are identified: dispersed bubbles, medium air pockets (MAP) and large air pockets (LAP). For the dispersed bubble case, the initially formed air pockets break into smaller bubbles and hence the water level rises linearly. For the MAP case, the size of the air pockets remains larger than for the dispersed bubble case, though, with time they burst at the surface. Finally, for the LAP case, the inkling jet interacts violently with the wall and hence large air pockets are trapped within the column, causing the overflow of the fluid. The flows are further analysed using non-dimensionless Reynolds and Froude numbers, providing an acceptable range of operating parameters that ensure the fluid does not overflow.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
Abadi, Pouria Khalili AtaKheradmand, SaeidNejad, Javad Vaziri Naeen
15页
查看更多>>摘要：This study has been investigated the effect of the height variation of the cyclone components under the non-uniform flow. Oscillating flow is an approach to consider the real flow condition in the use of cyclones as an inlet air filter for the internal combustion engine. Accordingly, an oscillating flow with an inlet velocity of 15 (m/s) along with a range of pressure based on the motor inlet is applied to the cyclones dirty and clean outlets. Seven cyclone models including a base model, and models with height change in vortex finder, cylinder, and cone have been created and gridded. The numerical solution has been run using the Large Eddy Simulation and the EulerianLagrangian model. Having validated, the flow field and cyclone performance have been considered. The results indicate that under the non-uniform flow, a decrease in the vortex finder height and an increase in the height of the cyclones cylinder and cone minimize the pressure drop. Applying oscillations along with the 30% change in the vortex finder height increases vortices power in the cone, cylinder, and vortex finder zones by 4.23, 8.99, and 21.42 percent, respectively. Additionally, the efficiency dependence on the change in length of cyclone components under the uniform flow is much higher than that of under the non-uniform flow. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：The discharge of fluids with complex rheological properties from industrial tanks, pipes, dispensers, or packaging containers through an orifice is a complex process often encountered in industry, which, if not properly characterized, can result in slow discharge and significant residual fluid left in the container. The discharge is strongly affected by the orifice geometry and fluid rheology. In this article, we review and summarize the current state-of-the-art in the discharge of complex fluids through orifices. While general correlations to predict the orifice flow are available, a more in-depth analysis of the fluid dynamics of the orifice discharge process as well as innovative surface modification techniques are required to improve industrial equipment design, process operation, and consumer packaging. Future perspectives that have the potential to address discharge issues and decrease the amount of waste are also discussed, including the utilization of high-precision multi-dimensional flow monitoring techniques such as Particle Image Velocimetry (PIV) and Magnetic Resonance Imaging (MRI), computational methods such as Computational Fluid Dynamics (CFD), and recent innovative surface modification techniques reducing fluid-container interaction, thus avoiding the no-slip boundary condition that causes viscous fluids to adhere to the container. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Production of 5-hydroxymethylfurfural from sugar beet molasses as feed-stock should in theory be a straight-forward process: first, hydrolysis of sucrose, followed by dehydration of fructose, but is in reality challenging. The enzyme-catalysed sucrose hydrolysis is inhibited by impurities and the dehydration of fructose has low conversions. In this study, pretreatment of crude molasses through purification using membrane filtration was investigated. The pretreatment process was evaluated with respect to the sucrose hydrolysis reaction rates and for the downstream 5-hydroxymethylfurfural production. Results from the ultra-/nanofiltration experiments showed good filtration fluxes (1134 L/m(2) h bar), high flux recovery after being heavily fouled (>80%) and ability to purify sucrose. The sucrose hydrolysis results showed an improved reaction rate for nanofiltered molasses (concentrate), while the ultrafiltration permeate showed no major difference from the crude molasses, indicating that the inhibitory compounds are of low molecular weight. Furthermore, the ultrafiltered molasses showed highly efficient fructose conversion (near 100%) and 5-hydroxymethylfurfural selectivity of 57% in the biphasic acid-catalysed dehydration, in contrast to only 49% fructose conversion in the crude molasses. (C) 2022 The Author(s). Published by Elsevier Ltd on behalf of Institution of Chemical Engineers.
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