de Castro, Tarsila F.Cortez, Daniela, VGoncalves, Daniel B.Bento, Heitor B. S....
8页
查看更多>>摘要：The study deals with the direct use of whole cells of a species of Penicillium as biocatalyst (mycelium-bound lipase) for the hydrolysis of vegetable oils under low-power ultrasonic irradiation. Whole cells of Penicillium purpurogenum with lauric acid-specificity lipase were able to hydrolyze vegetable oils with high content of this fatty acid. Up to 90% hydrolysis values were reached at 7 h of reaction, providing high fatty acid contents in shorter times concerning the literature. The results suggest that the ultrasound wave improves the interfacial area and that the lipase of Penicillium purpurogenum is bound to the cell, in a place with easy access to the substrate. On the other hand, the presence in the substrate of fatty acids with 18 carbons (stearic, oleic, and linoleic) in a concentration greater than 20%, negatively interferes with the degree of hydrolysis, indicating a possible limitation of lipase specificity. The present study highlights the biotechnological potential of mycelium-bound lipase (naturally immobilized enzymes) for use in the hydrolysis of babassu, coconut and kernel oils, which are not directly integrated into the food production chain.(c) 2022 Published by Elsevier Ltd on behalf of Institution of Chemical Engineers.
查看更多>>摘要：The propagation of premixed hydrogen-air deflagration flames in a closed duct with different shapes of obstacles was investigated using large eddy simulation (LES). The turbulent flame wrinkling factor in the LES subgrid turbulent combustion model is dynamically modeled based on Charlette's power-law model. The LES results obtained by the dynamic flame surface density (DFSD) model can accurately match the experimental data quantitatively and qualitatively. Numerical results show that the triangular obstacle induces a higher peak overpressure, 7% and 30% higher than that in the square and circle, respectively. The formation of juxtaposed tulip flames is discovered, and the topological analysis of the velocity vector field reveals that the vortex at the tail of the obstacle is the main inducing factor for its formation. Additionally, the Karlovitz number is used to quantify the degree of turbulence-flame interaction, and the transition of deflagration flame from "wrinkled flame" to "thin reaction zone" is observed. The research helps to un-derstand the mechanism of deflagration flame propagation induced by obstacles and provides critical in-formation for safety planning and explosion protection.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Industrial gaseous emissions of volatile organic compounds (VOCs) may result in adverse effects to en-vironment and human health, thus must be removed from flue gas before emitted to the atmosphere. Here we present a study of a real-world testing of a novel hybrid gas-to-particle conversion system targeting VOC removal from the ventilation air originating at wood processing facilities. Terpenes (primarily alpha-pinene, beta-pinene, and alpha-terpineol) were targeted as the prevailing VOCs. The system was realized as a single-pass reactor having multiple stages of plasmolysis/ozonolysis, photolysis, nucleation, coagulation and agglom-eration of aerosols, as well as precipitation of agglomerates in an electrostatic field. The VOC removal ef-ficiency in terms of total VOCs (TVOCs) has reached 92.8%, while 100% removal efficiency of alpha-pinene, beta-pinene, and alpha-terpineol was achieved with the non-thermal plasma (NTP) operating at a specific energy input (SEI) of 3.6 J/L (42 J/L of entire system). The advanced gas-phase oxidation system proved to be competitive in treating VOC polluted flue gases in terms of removal efficiency and relatively low energy input. The results hereafter promote faster development and extensive industrial application of gas-phase advanced oxidations systems based on the gas-to-particle conversion process.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：As one of the typical multi-hazard natural disasters, floods and hurricanes have caused destructive damage to the process equipment, especially vertical storage tanks, leading to a large number of severe technological accidents in chemical industrial parks. In the present study, aiming at the buckling behavior under the coupling effect of floods and hurricanes, the wind load, flood load, and wave load are analyzed, and the limit state equation of storage tank buckling failure under the coupling effect of floods and hurricanes is established. Then, the load distribution on the tank wall is verified by FLUENT software and the rationality of FLUENT simulation is shown by laboratory experiments of vertical storage tanks. The fragility curves and surfaces are plotted by Monte Carlo Simulation under different wind speeds, considering the effects of flood velocity, flood inundation height, and liquid filling level. The results show that with the increase of wind speed, the influence of flood inundation height on the vulnerability of storage tanks gradually increases, while the influence of flood velocity and filling level on the vulnerability of storage tanks gradually decreases. Flood inundation height is the main disaster parameter affecting the vulnerability of storage tanks. Compared with the case of floods or hurricanes alone, the buckling failure probability of storage tanks under the coupling effects of floods and hurricanes increases by 17.67% and 80.50%, respectively. Moreover, the damaging effect of the coupling of floods and hurricanes is greater than that of the direct superposition effect, and the failure probability increases by 17.57%. The research aims to analyze the failure mechanism of vertical storage tanks, accident prevention, and control under the coupling effects of multiple hazards. (c) 2022 Published by Elsevier Ltd on behalf of Institution of Chemical Engineers.
查看更多>>摘要：Four antibiotics common in wastewater, namely sulfadiazine (SD), sulfamethoxazole (SMX), ciprofloxacin (CIP), and norfloxacin (NOR), were used in the treatment of wastewater by constructed rapid infiltration (CRI), using coke as filler material. Results showed that the removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3-N) and the total phosphorus (TP) of the sulfonamide antibiotics infiltration column reached 75.01%, 40.79% and 91.22%, respectively, which were 6.61%, 12.13% and 2.68% lower than those of the quinolone antibiotics infiltration column. With increasing antibiotic concentration (2-10 mg/L), the removal of SD showed a downward trend. The average removal rates of CIP and NOR by the CRI reached 34.65% and 43.57%, respectively. Oxygen-containing functional groups of the coke played a positive role in the removal of antibiotics. The dehydrogenase (DH) activity in the sulfonamide infiltration column was 0.62 mu g/(g center dot mL), which was 0.48 mu g/(g center dot mL) lower than that of the quinolone infiltration column. Meanwhile, the activity of phosphatase (AKP) in the sulfonamide infiltration column was 0.06 mg/(g center dot h), 0.30 mg/(g center dot h) lower compared to that of the quinolone infiltration column. Microbial community was dominated by Actinomycetes (38.52-55.93%) at the phylum level and by Arthrobacter (34.0 0-49.20%) at the genus level, especially in the sulfonamide infiltration column. Based on Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analysis, carbohydrate (10.79-11.52%) and amino acid metabolism (10.79-11.27%) were the main bacterial pathways. Overall, sulfonamide antibiotics more negative impacted wastewater treatment by the CRI than quinolone antibiotics. (c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Nonylphenol Ethoxylate (NPEO) is a non-ionic surfactant used worldwide in the formulation of cleaning products. Removal of these compounds from domestic sewage is difficult to achieve. In this study, the degradation of NPEO from the co-digestion of domestic sewage (DS) and commercial laundry wastewater (CLW) was evaluated using a pilot-scale expanded granular sludge bed (EGSB) reactor operated for 637 days. In phase I, the reactor was fed with synthetic substrate (SS) - without NPEO, phases II and III with SS plus 3.5 +/- 1.0 mgNPEO L-1 and 7.6 +/- 2.1 mgNPEO L-1, respectively. Phase IV with SS plus CLW containing 4.0 +/- 1.1 mgNPEO L-1, phase V with DS plus CLW and 3.7 +/- 1.3 mgNPEO L-1. Nearly 60% of NPEO was biodegraded and chemical oxygen demand (COD) removal varied from 90 +/- 5% to 97 +/- 2% (for up to 573.8 +/- 130.1 mgCOD L-1). Spirochaetacea exhibit the greatest relative abundance (from 65.3% to 90.7%) throughout the operation. NPEO addition negatively affected methanogenic activity, such that CH4 yield decreased 91% even at high COD removal. Surprisingly, after 549 days of operation, a CH4 yield of 0.30 +/- 0.14 LCH4 gCOD(-1) removed was observed. (C)& nbsp;2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
Idris, Ahmad MuzammilRusli, RiszaNasif, Mohammad ShakirRamli, Ahmad Fakrul...
12页
查看更多>>摘要：A flammable gas detection system is one of the critical control strategies of catastrophic events such as fire and explosion. While gas detector technology has improved significantly, adopting a methodology for optimal placement of gas detectors is still an issue, especially when integrated with a risk-based approach. An enhancement of a risk-based approach is proposed to optimise the placement of flammable gas detectors by integrating a formulation of fuzzy multi-objective mixed-integer linear programming with the goal of minimising the residual risk and total number of detectors for effective explosion protection. The proposed methodology primarily begins with the identification of critical leak scenarios that require detection followed by the prediction of a targeted gas cloud and dispersion analysis using a computational fluid dynamic model. Risk analysis is conducted to identify high risk areas that need flammable gas detectors protection, which is the input for the mathematical model. The proposed risk-based model was tested using a case study involving a natural gas liquids (NGL) recovery unit, and the results were compared to a published greedy algorithm (GA) formulation. By using mixed-integer linear programming (MILP) formulation, the number of detectors needed are lower with higher risk reductions compared to the GA formulation. Additionally, a sensitivity analysis was performed to determine the proposed model's response to parameter variations. (c) 2022 Published by Elsevier Ltd on behalf of Institution of Chemical Engineers.
查看更多>>摘要：The turbulent explosion process of stoichiometric CH4/C2H4/air mixtures was experimentally studied by using a standard 20 L sphere explosion system and it's powder storage tank as the turbulence generator. Taking the initial turbulent environment and ethylene volume fraction as variables, the effects of turbulence intensity and fuel composition on explosion characteristics were studied. The results show that both turbulence intensity and ethylene content promote the explosion of the mixtures and increase the severity of the explosion, but the influence of turbulence intensity on combustion evolution mainly focuses on heat loss, while the influence of ethylene content mainly focuses on adiabatic explosion. When the ethylene ratios increase to 0.5 or more, the increase of explosion severity caused by turbulence is not obvious. The analysis of experimental results and numerical simulation shows that the influence of initial turbulence generated by powder storage tank on explosion is the result of the combined action of turbulent kinetic energy and combustible gas redistribution. (c) 2022 Published by Elsevier Ltd on behalf of Institution of Chemical Engineers.
查看更多>>摘要：Bioretention system has been commonly recognized as an emerging management method to control urban rainwater runoff. However, nitrogen conversion mechanisms in bioretention system in response to for-mulated soil medium remains unknown. In this work, five bioretention columns with different formulated soil medium were established, and results indicated that all bioretention columns achieved high NH4+-N removal rate, but exhibited significantly different NO3--N removal performance. High-throughput se-quencing results suggested that nitrification might be achieved by heterotrophic nitrifying bacteria, while Pseudomonas and Rubellimicrobium may be the main denitrifying bacteria, which served as anaerobic and aerobic denitrifier, respectively. Heterotrophic nitrification-anaerobic/aerobic denitrification may the mi-crobial pathways to realize effective nitrogen removal performance in these bioretention systems. Bioretention system with moderate silt content (NC, 10%) displayed higher abundant potential denitrifier, leading to better nitrogen removal performance. Besides, soil adsorption played an important role in ni-trogen removal, particularly when activated carbon was added. This work could provide guidance of for-mulated soil medium optimization for the application of bioretention systems. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
查看更多>>摘要：Propane (R290) is a widely used environmentally friendly refrigerant with excellent thermodynamic properties, but it may burn once it leaks. Therefore, it is imperative to investigate the combustion mechanism of leaking propane. A series of ReaxFF molecular dynamic simulations were employed, and the reactions involving the decomposition of propane were investigated by density functional theory (DFT), and the results of the ReaxFF molecular dynamic simulations were clarified by comparing the energy barriers, bond dissociation energies and reaction energies required for the reactions. The results indicated that the chemical role of H2O was mainly reflected by the reactions of H2O molecules with H and O radicals to form OH radicals and H-2 molecules. The combustion of propane was promoted by the presence of a low concentration of H2O molecules. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.
NSTL
Elsevier