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1
Franklin, Simon. "Reactor reaction." Physics World 11, no. 5 (May 1998): 22. http://dx.doi.org/10.1088/2058-7058/11/5/20.
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Omoregbe, Osaze, Artur Jacek Majewski, and Robert Steinberger-Wilckens. "CO2 Methanation over an Ni/YSZ Catalyst: Impact of Altering the Catalyst Bed Ratio in Two Reactors in Series." ECS Meeting Abstracts MA2023-01, no. 28 (August 28, 2023): 2841. http://dx.doi.org/10.1149/ma2023-01282841mtgabs.
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CO2 methanation is a promising method of preventing the wastage of excess energy generated from renewable electricity sources such as wind and solar. The excess energy is used to power an electrolytic cell to produce H2 which is then reacted with CO2 to form CH4 (chemical energy). The stored CH4 can be converted back to electric energy and released into the power grid whenever energy demand exceeds production. To achieve the best result, a suitable catalyst and good reactor design are crucial. Therefore, this study investigated the effect of varying the catalyst ratio in two reactors in series, including water removal, for CO2 methanation over a 10%Ni/YSZ catalyst. The water removal was installed to prevent or minimise the interference effect of water formed in the reactor on the catalyst along the further reactor bed. The results revealed that the reactor configurations with less catalyst in the first reactor compared to the second reactor generally showed better performances. These results can be attributed to the fact that the majority of the water produced in the first reactor was trapped before entering the second reactor since the quantity was small while the reacting species entering reactor 2 had more active sites for the reaction to take place. This study has shown that the ratio of catalysts in multiple reactors connected in series considerably influences the performance of the system. The hydrogenation of CO2 into CH4, also known as CO2 methanation, can help to resolve the problem of safe storage and transportation associated with H2, since CH4 has a higher volumetric energy density [C. Wang, Nano Res. (2023) 1–12, L. Shi, J. Energy Storage. 62 (2023) 106846]. In addition, CO2 methanation is a promising method of preventing the wastage of excess energy generated from renewable sources such as wind and solar. The excess energy is used to power an electrolytic cell to produce H2 which then is reacted with CO2 to form CH4 (chemical energy). The stored CH4 can be converted back to electric energy and released into the power grid whenever energy demand exceeds production, or more generally be used as a substitute for natural gas. The activity of the Ni/YSZ catalyst was examined in two fixed-bed quartz reactors arranged in series with a water trap. The product stream was analysed by gas chromatography. We investigated the effect of varying the catalyst ratio in the two-reactor configuration in series with a water trap for CO2 methanation over the 10%Ni/YSZ catalyst. The water trap was installed to prevent or at least minimise the interference effect of water formed in the first reactor on the catalyst in reactor 2. Many studies have reported that water has a negative effect on the activity of catalysts during CO2 methanation. The water from reactor 1 will compete with other reacting species at the catalyst active sites if not removed before entering reactor 2. For example, Hernandez et al. [Chem. Eng. J. 390 (2020) 124629] reported that the addition of water in the feed caused a negative effect during CO2 methanation. Hashemi et al. [Energies. 14 (2021)] also found that the removal of water significantly improved the average reaction rate within the reactor, leading to an increase in CO2 conversion within a reactor operating at static conditions. It is also believed that the removal of water before the reactant stream enters the second reactor helps to overcome the thermodynamic limitations of conversion [S.E. Hashemi, Energies. 14 (2021)]. The effect of varying the catalyst ratios in two reactors in series with water removal for CO2 methanation over 10%Ni/YSZ catalyst was studied. The water trap was installed to prevent or minimise the interference effect of water formed in reactor 1 on the catalyst in reactor 2. The results revealed that the reactor configurations with less catalyst in the first reactor compared to the second reactor generally showed better performances. These interesting results can be attributed to the fact that as the majority of the water produced in the first reactor was trapped before entering the second reactor, the reacting species entering reactor 2 had more active sites for the reaction to take place, as they were not competing with the water molecules. This resulted in a better overall conversion rate. This study has shown that the ratio of catalysts in multiple reactors connected in series influences the performance of the system, along with the provision of product water removal along the reaction pathway.
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Bankovic-Ilic, Ivana, Marija Miladinovic, and Vlada Veljkovic. "Continuous reciprocating plate and packed bed multiphase reactors in biodiesel production: Advancements and challenges." Chemical Industry, no. 00 (2024): 10. http://dx.doi.org/10.2298/hemind230630010b.
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Biodiesel, a renewable and environmentally friendly alternative to conventional fossil fuels, has gained significant attention over the last two decades. Continuous production of biodiesel offers efficiency, productivity, and scalability advantages. This paper provides a concise overview of continuous reactor systems for biodiesel production, focusing on two specific systems-the reciprocating plate reactor and the packed bed reactor-subjects of the authors' extensive research. A thorough comparison of these reactors, spanning biodiesel yield, reaction kinetics, and conversion efficiency, underscores their advantages. The reciprocating plate reactor demonstrates superior mixing characteristics, which improve mass transfer and reaction kinetics. Conversely, the packed bed reactor offers a higher catalyst-to-feedstock ratio and longer residence time, enhancing conversion efficiency. Both reactors exhibit favourable performance for continuous biodiesel production. This research can contribute to understanding continuous biodiesel production using innovative reactor designs. The comparative analysis between the reciprocating plate and packed bed reactors offers valuable insights for process optimization and reactor selection based on specific requirements such as feedstock availability, reaction kinetics, and economic considerations. These insights pave the way for the implementation of sustainable and efficient biodiesel production processes in the future.
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Lu, Ningning, and Donglai Xie. "Novel Membrane Reactor Concepts for Hydrogen Production from Hydrocarbons: A Review." International Journal of Chemical Reactor Engineering 14, no. 1 (February 1, 2016): 1–31. http://dx.doi.org/10.1515/ijcre-2015-0050.
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AbstractMembrane reactors are attracting increasing attention for ultrapure hydrogen production from fossil fuel, integrating catalytic reaction and separation processes into one single unit thus can realize the removal of hydrogen or introduction of reactant in situ, which removes the thermodynamic bottleneck and improves hydrogen yield and selectivity. In this review, the state-of-the-art concepts for hydrogen production through membrane reactors are introduced, mainly including fixed bed membrane reactors, fluidized bed membrane reactors, and micro-channel membrane reactors, referring higher hydrocarbons as feedstock, such as ethanol, propane, or heptane; novel heating methods, like solar energy realized through molten salt; new modular designs, including panel and tubular configurations; ultra-compact micro-channel designs; carbon dioxide capture with chemical looping; multifuel processors for liquid and/or solid hydrocarbons; etc. Recent developments and commercialization hurdles for each type of membrane reactor are summarized. Modeling the reactor is fundamental to explore complex hydrodynamics in reactor systems, meaningful to investigate the effects of some important operating factors on reactor performances. Researches for reactor modeling are also discussed. Reaction kinetics for hydrocarbons reforming and reactor hydrodynamics are summarized respectively. Cold model is introduced to investigate physical phenomena in reactors.
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Elmaleh, S., T. I. Yoon, and A. Grasmick. "Influence of Macromixing on Organic Carbon Uptake and Solids Production by Aerobic Suspended Biomass." Water Science and Technology 17, no. 2-3 (February 1, 1985): 209–19. http://dx.doi.org/10.2166/wst.1985.0131.
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The influence of macromixing on organic carbon uptake by aerobic suspended biomass has been investigated using two reactors operated in parallel, i.e. a perfectly mixed reactor and a compartmented reactor. Conversion determined on filtrated samples is identical in both of the reactors but with less solids production in the low-dispersed reactor. The reaction rate established on the perfectly mixed reactor shows an apparent first-order with influence of inlet concentration but this relation cannot be used in a mass balance over the compartmented reactor.
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Kong, Rui, Lingen Chen, Shaojun Xia, Penglei Li, and Yanlin Ge. "Minimization of Entropy Generation Rate in Hydrogen Iodide Decomposition Reactor Heated by High-Temperature Helium." Entropy 23, no. 1 (January 8, 2021): 82. http://dx.doi.org/10.3390/e23010082.
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The thermochemical sulfur-iodine cycle is a potential method for hydrogen production, and the hydrogen iodide (HI) decomposition is the key step to determine the efficiency of hydrogen production in the cycle. To further reduce the irreversibility of various transmission processes in the HI decomposition reaction, a one-dimensional plug flow model of HI decomposition tubular reactor is established, and performance optimization with entropy generate rate minimization (EGRM) in the decomposition reaction system as an optimization goal based on finite-time thermodynamics is carried out. The reference reactor is heated counter-currently by high-temperature helium gas, the optimal reactor and the modified reactor are designed based on the reference reactor design parameters. With the EGRM as the optimization goal, the optimal control method is used to solve the optimal configuration of the reactor under the condition that both the reactant inlet state and hydrogen production rate are fixed, and the optimal value of total EGR in the reactor is reduced by 13.3% compared with the reference value. The reference reactor is improved on the basis of the total EGR in the optimal reactor, two modified reactors with increased length are designed under the condition of changing the helium inlet state. The total EGR of the two modified reactors are the same as that of the optimal reactor, which are realized by decreasing the helium inlet temperature and helium inlet flow rate, respectively. The results show that the EGR of heat transfer accounts for a large proportion, and the decrease of total EGR is mainly caused by reducing heat transfer irreversibility. The local total EGR of the optimal reactor distribution is more uniform, which approximately confirms the principle of equipartition of entropy production. The EGR distributions of the modified reactors are similar to that of the reference reactor, but the reactor length increases significantly, bringing a relatively large pressure drop. The research results have certain guiding significance to the optimum design of HI decomposition reactors.
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Kong, Rui, Lingen Chen, Shaojun Xia, Penglei Li, and Yanlin Ge. "Minimization of Entropy Generation Rate in Hydrogen Iodide Decomposition Reactor Heated by High-Temperature Helium." Entropy 23, no. 1 (January 8, 2021): 82. http://dx.doi.org/10.3390/e23010082.
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The thermochemical sulfur-iodine cycle is a potential method for hydrogen production, and the hydrogen iodide (HI) decomposition is the key step to determine the efficiency of hydrogen production in the cycle. To further reduce the irreversibility of various transmission processes in the HI decomposition reaction, a one-dimensional plug flow model of HI decomposition tubular reactor is established, and performance optimization with entropy generate rate minimization (EGRM) in the decomposition reaction system as an optimization goal based on finite-time thermodynamics is carried out. The reference reactor is heated counter-currently by high-temperature helium gas, the optimal reactor and the modified reactor are designed based on the reference reactor design parameters. With the EGRM as the optimization goal, the optimal control method is used to solve the optimal configuration of the reactor under the condition that both the reactant inlet state and hydrogen production rate are fixed, and the optimal value of total EGR in the reactor is reduced by 13.3% compared with the reference value. The reference reactor is improved on the basis of the total EGR in the optimal reactor, two modified reactors with increased length are designed under the condition of changing the helium inlet state. The total EGR of the two modified reactors are the same as that of the optimal reactor, which are realized by decreasing the helium inlet temperature and helium inlet flow rate, respectively. The results show that the EGR of heat transfer accounts for a large proportion, and the decrease of total EGR is mainly caused by reducing heat transfer irreversibility. The local total EGR of the optimal reactor distribution is more uniform, which approximately confirms the principle of equipartition of entropy production. The EGR distributions of the modified reactors are similar to that of the reference reactor, but the reactor length increases significantly, bringing a relatively large pressure drop. The research results have certain guiding significance to the optimum design of HI decomposition reactors.
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Popa, Simona, Andra Tamas, Vasile Simulescu, Dorin Jurcau, Sorina Boran, and Giannin Mosoarca. "A Novel Approach of Bioesters Synthesis through Different Technologies by Highlighting the Lowest Energetic Consumption One." Polymers 13, no. 23 (November 30, 2021): 4190. http://dx.doi.org/10.3390/polym13234190.
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Fatty acids esters have a wide application as bioplasticizers and biolubricants in different industries, obtained mainly in classic batch reactors, through an equilibrium complex reaction, that involves high temperatures, long reaction times, vigorously stirring, and much energy consumption. To overcome these shortcomings, we synthesized a series of fatty acid esters (soybean oil fatty acids being the acid components with various hydroxyl compounds) through novel low energy consumption technologies using a bubble column reactor, a microwave field reactor and for comparison meaning, a classic batch reactor. The obtained bioesters physicochemical properties were similar to one another, a good concordance among their rheological properties was obtained, but the energetic consumption is lower when using the bubble column or the microwave reactors instead of the classical batch reactor.
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Selvamony, Subash Chandra Bose. "Kinetics and Product Selectivity (Yield) of Second Order Competitive Consecutive Reactions in Fed-Batch Reactor and Plug Flow Reactor." ISRN Chemical Engineering 2013 (September 12, 2013): 1–17. http://dx.doi.org/10.1155/2013/591546.
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This literature compares the performance of second order competitive consecutive reaction in Fed-Batch Reactor with that in continuous Plug Flow Reactor. In a kinetic sense, this simulation study aims to develop a case for continuous Plug Flow Reactor in pharmaceutical, fine chemical, and related other chemical industries. MATLAB is used to find solutions for the differential equations. The simulation results show that, for certain cases of nonelementary scenario, product selectivity is higher in Plug Flow Reactor than Fed-Batch Reactor despite the fact that it is the same in both the reactors for elementary reaction. The effect of temperature and concentration gradients is beyond the scope of this literature.
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Smith, R. C., and D. B. Oerther. "Microbial community development in a laboratory-scale nitrifying activated sludge system with input from a side-stream bioreactor treating digester supernatant." Water Science and Technology 54, no. 1 (July 1, 2006): 209–16. http://dx.doi.org/10.2166/wst.2006.389.
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Three laboratory-scale activated sludge treatment trains were operated to investigate the effect on biodiversity in plug flow (PFR) main-stream sewage treatment from input of biomass from side-stream reactors treating anaerobic digester supernatant. One train had a completely mixed (CSTR) side-stream reactor, one a PFR side-stream reactor, and the third train was a control that did not receive input from a side-stream reactor. Restriction endonucleases were used to digest polymerase chain reaction-amplified ammonia monooxygenase subunit A (amoA) genes in monthly samples from each reactor. Restriction fragment banding patterns from polyacrylimide gel electrophoresis indicated that the structure of the ammonia oxidizing bacteria (AOB) populations in all five reactors stabilized by the fourth month of operation and then did not vary subsequently. Furthermore, a dendrogram generated using the Jaccard distance showed that the AOB in each side-stream reactor was most similar to the main-stream reactor in the same train indicating that the AOB population in the side-stream reactor exerts a strong influence on the population in the main-stream reactor. Sequencing results indicated that Nitrosomonas europea, an r-strategist, was the dominant AOB in the PFR side-stream reactor, while Nitrosomonas europea and Nitrosomonas marina, a marine bacterium, were strongly represented in the CSTR side-stream reactor.
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Primozic, Mateja, Maja Habulin, Muzafera Paljevac, and Zeljko Knez. "Enzyme-catalyzed reactions in different types of high-pressure enzymatic reactors." Chemical Industry and Chemical Engineering Quarterly 12, no. 3 (2006): 159–63. http://dx.doi.org/10.2298/ciceq0603159p.
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The enzyme-catalyzed hydrolysis of carboxy-methyl cellulose (CMC) was performed in three different types of reactors; in a batch stirred-tank reactor (BSTR) operating at atmospheric pressure, in a high-pressure batch stirred-tank reactor (HP BSTR) and in a high-pressure continuous tubular-membrane reactor (HP CTMR). In the high-pressure reactors aqueous SC CO2 was used as the reaction medium. The aim of our research was optimization of the reaction parameters for reaction performance. All the reactions were catalyzed by cellulase from Humicola insolens. Glucose production in the high-pressure batch stirred-tank reactor was faster than in the BSTR at atmospheric pressure. The optimal temperature for the reaction performed in the BSTR at atmospheric pressure was 30?C, while the optimal temperature for the reaction performed in SC CO2 was 32?C. The influence of the application of tubular ceramic membranes in the high-pressure reaction system was studied on the model reaction of CMC hydrolysis at atmospheric pressure and in SC CO2. The reaction was catalyzed by cellulase from Humicola insolens covalently linked to the surface of the ceramic membrane. The hydrolysis of CMC in SC CO2 and at atmospheric pressure was performed for a long time period. The reaction carried out in SC CO2 was more productive than the reaction performed at atmospheric pressure.
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BUISMAN, C., B. WIT, and G. LETTINGA. "Biotechnological sulphide removal in three polyurethane carrier reactors: stirred reactor, biorotor reactor and upflow reactor." Water Research 24, no. 2 (February 1990): 245–51. http://dx.doi.org/10.1016/0043-1354(90)90110-r.
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Yao, Qikai. "The challenges of nuclear fusion reactor." Theoretical and Natural Science 11, no. 1 (November 17, 2023): 105–10. http://dx.doi.org/10.54254/2753-8818/11/20230387.
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Energy shortage is one of nonnegligible problems nowadays. Even since the twenty centuries, the achievement of fission reactor has proved that nuclear energy is a powerful source. However, fission reaction could cause radiation hazard if operation error happens. Nuclear fusion can provide more clean energy. This paper discusses nuclear fusion and two typical models of fusion reactor, inertial confinement fusion reactor and tokamak, and their properties. Fusion reactors use deuterium and tritium to fuse heavier nucleus and release energy. With -distribution, deuterium-tritium fusion reactivity can be boosted at relatively low temperature. Furthermore, fusion reactor has initial success. The more energy can be created than energy used to ignition. To solve nuclear fuel problem, continue ignition progress problem, possibly achieving controllable fusion reaction. The improvements which this paper mentioned perhaps allow to extend the application context of fusion reactor.
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Soponpongpipat, Nitipong, Suwat Nanetoe, and Paisan Comsawang. "Thermal Degradation of Cassava Rhizome in Thermosyphon-Fixed Bed Torrefaction Reactor." Processes 8, no. 3 (February 26, 2020): 267. http://dx.doi.org/10.3390/pr8030267.
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A thermosyphon-fixed bed reactor was designed and constructed to investigate the temperature distribution of the cassava rhizome and its decomposition behavior. To study the properties of torrefied char obtained from this reactor, cassava rhizome was torrefied in five different configurations, including the thermosyphon-fixed bed reactor, a laboratory reactor in compact bulk arrangement with N2 as the purge gas and without any purge gas, and another one in a hollow bulk arrangement with and without purge gas. It was found that the use of thermosyphons with a fixed bed reactor improved the uniform temperature distribution. The average heating rate to the cassava rhizome bed was 1.40 °C/min, which was 2.59 times higher than that of the fixed bed reactor without thermosyphons. Compared to the other configurations, this reactor gave the highest higher heating value (HHV) and the lowest mass yield of 23.97 MJ/kg and 47.84%, respectively. The water vapor produced in this reactor played an autocatalyst role in the decomposition reaction. Finally, the thermosyphon-fixed bed reactor gave an energy yield in the range of 70.43% to 86.68%. The plot of the HHV ratio–mass yield diagram indicated the difference of torrefied char obtained from different reactors. The thermosyphon-fixed bed reactor produced torrefied biomass with the highest HHV ratio compared to that of other reactors at the same energy yield.
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Muhammad Asyraaf Asri, Nurul Fitriah Nasir, Ishkrizat Taib, and Djamal Hissein Didane. "Prediction of Fluid Pattern of Biodiesel Production in a Membrane Reactor." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 111, no. 1 (December 28, 2023): 156–65. http://dx.doi.org/10.37934/arfmts.111.1.156165.
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Utilization of membrane reactors for biodiesel production has been an alternative to conventional batch reactors. The membrane in the reactor acts as a separation layer, preventing the formation of by-products and allowing the desired biodiesel product to pass through. This can improve yields and reduce waste, making the process more environmentally friendly and economically viable. This study aimed to analyze the fluid flow and velocity profile inside the membrane reactor and determine the volume fraction of biodiesel. The modeling and simulation of the fluid flow of biodiesel in a membrane reactor was carried out using SOLIDWORK and ANSYS software. Using a Eulerian-Eulerian two-fluid model, multiphase simulations were carried out. Three different temperatures, 333 K, 338 K, and 343 K, were used in the simulation. The results have found that at 333K, the biodiesel production in the membrane reactor shows the best flow characteristics compared to reaction temperatures of 338 K and 343 K. Additionally, the highest volume fraction can be predicted at the temperature of 333K. Further research and simulation study can be implemented to explore the effects of inlet velocity and reaction time on the fluid flow pattern of biodiesel inside the membrane reactor.
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Song, Lin, Xin Zhang, Xiao Long Zeng, and Ming Yu Li. "Role of the Cathode in a Novel Photo-Electro-Chemical Catalytic Reactor." Advanced Materials Research 455-456 (January 2012): 985–90. http://dx.doi.org/10.4028/www.scientific.net/amr.455-456.985.
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A novel photo-electro-chemical catalytic reactor with single/double-tank was designed. TiO2/Ti thin film electrode was used as photo-anodes, graphite as cathode and a saturated calomel electrode (SCE) as the reference electrode in the reactor. The efficiency of photo-electro-chemical catalysis was enhanced because the target pollutant was degraded not only titanium dioxide electrode in anodic tank, but also hydrogen peroxide through reducing dissolved oxygen with graphite electrode in catholyte. Malachite green (MG) and crystal violet (CV) were degradated effectively in these two reactors. The degradation efficiency of the double-tank reactor is superior to that of single-tank reactor and its apparent reaction rate constant is twice or more of than that of the single-tank reactor, which was result from the higher concentration of H2O2 in the double-tank reactor. In the single-tank reactor, H2O2 generated during cathodal reaction diffused to the anode and was consumed, while it could be prevented in the double-tank reactor. Under the conditions of cathodic potential Ec at-0.6V, initial solution pH at 3.0 and initial solution concentration 30 mg·L-1, the catalytic degradation of MG and CV were both pseudo-first order reactions.
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Borovinskaya, Ekaterina, Valentin Khaydarov, Nicole Strehle, Alexander Musaev, and Wladimir Reschetilowski. "Experimental Studies of Ethyl Acetate Saponification Using Different Reactor Systems: The Effect of Volume Flow Rate on Reactor Performance and Pressure Drop." Applied Sciences 9, no. 3 (February 4, 2019): 532. http://dx.doi.org/10.3390/app9030532.
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Microreactors intensify chemical processes due to improved flow regimes, mass and heat transfer. In the present study, the effect of the volume flow rate on reactor performance in different reactors (the T-shaped reactor, the interdigital microreactor and the chicane microreactor) was investigated. For this purpose, the saponification reaction in these reactor systems was considered. Experimental results were verified using the obtained kinetic model. The reactor system with a T-shaped reactor shows good performance only at high flow rates, while the experimental setups with the interdigital and the chicane microreactors yield good performance throughout the whole range of volume flow rates. However, microreactors exhibit a higher pressure drop, indicating higher mechanical flow energy consumption than seen using a T-shaped reactor.
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Wei, Gui, and Hong Chang. "Design of Photocatalytic Reactor with Photocatalyst Film Loaded on Substrate." Advanced Materials Research 823 (October 2013): 214–17. http://dx.doi.org/10.4028/www.scientific.net/amr.823.214.
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After analytical studies of the characteristics of various slurry and supported photocatalytic reactors, a photocatalytic reactor with photocatalyst film loaded on substrate is designed in this paper. This reactor is characterized by the easy attachment and convenient installation & replacement of photocatalyst, higher light utilization, and complete photocatalytic reaction.
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Alinejad, Milad Mohammad, Kamran Ghasemzadeh, Adolfo Iulianelli, Simona Liguori, and Milad Ghahremani. "CFD Development of a Silica Membrane Reactor during HI Decomposition Reaction Coupling with CO2 Methanation at Sulfur–Iodine Cycle." Nanomaterials 12, no. 5 (February 28, 2022): 824. http://dx.doi.org/10.3390/nano12050824.
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In this work, a novel structure of a hydrogen-membrane reactor coupling HI decomposition and CO2 methanation was proposed, and it was based on the adoption of silica membranes instead of metallic, according to their ever more consistent utilization as nanomaterial for hydrogen separation/purification. A 2D model was built up and the effects of feed flow rate, sweep gas flow rate and reaction pressure were examined by CFD simulation. This work well proves the feasibility and advantage of the membrane reactor that integrates HI decomposition and CO2 methanation reactions. Indeed, two membrane reactor systems were compared: on one hand, a simple membrane reactor without proceeding towards any CO2 methanation reaction; on the other hand, a membrane reactor coupling the HI decomposition with the CO2 methanation reaction. The simulations demonstrated that the hydrogen recovery in the first membrane reactor was higher than the methanation membrane reactor. This was due to the consumption of hydrogen during the CO2 methanation reaction, occurring in the permeate side of the second membrane reactor system, which lowered the amount of hydrogen recovered in the outlet streams. After model validation, this theoretical study allows one to evaluate the effect of different operating parameters on the performance of both the membrane reactors, such as the pressure variation between 1 and 5 bar, the feed flow rate between 10 and 50 mm3/s and the sweep gas flow rate between 166.6 and 833.3 mm3/s. The theoretical predictions demonstrated that the best results in terms of HI conversion were 74.5% for the methanation membrane reactor and 67% for the simple membrane reactor.
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Chen, Junjie. "Hydrogen production in microchannel methanol steam reforming reactors." BASRA JOURNAL OF SCIENCE 40, no. 1 (June 3, 2022): 83–106. http://dx.doi.org/10.29072/basjs.20220105.
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Many attempts have been made to improve heat transfer for thermally integrated microchannel reforming reactors. However, the mechanisms for the effects of design factors on heat transfer characteristics are still not fully understood. This study relates to a thermochemical process for producing hydrogen by methanol steam reforming in a microchannel reactor. Computational fluid dynamics simulations are conducted to understand the consumption, generation, and exchange of thermal energy between endothermic and exothermic processes in the reactor. The effects of wall heat conduction properties and channel dimensions on heat transfer characteristics and reactor performance are investigated. A thermodynamic analysis is performed based on specific enthalpy to understand the evolution of thermal energy in the reactor. The results indicate that the thermal conductivity of the channel walls is fundamentally essential. Highly thermally-conductive solids are preferred for the channel walls. Wall materials with poor heat conduction properties degrade the reactor performance. Reaction heat flux profiles are considerably affected by channel dimensions. The peak reaction heat flux increases with the channel dimensions while maintaining the flow rates. The change in specific enthalpy is positive for the exothermic reaction and negative for the endothermic reaction. The change in specific sensible enthalpy is always positive. Design recommendations are made to improve thermal performance for the reactor.
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Sargsyan, Garnik, Anatolii Silveistr, Mykhailo Lysyi, Mykola Mokliuk, and Hrachya Sargsyan. "The appearance of standing wave structures in the reaction medium during the diffusion development of the chain reaction process." Scientific Herald of Uzhhorod University Series Physics, no. 54 (November 20, 2023): 36–46. http://dx.doi.org/10.54919/physics/54.2023.36.
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Relevance. Understanding the dynamic behavior of radicals in reactors undergoing gas-phase oxidation of organic substances is crucial for optimizing reactor design and safety across industries. Purpose. This study aims to elucidate the emergence of standing wave structures influenced by feedback mechanisms in reactors with cylindrical and spherical symmetry, using mathematical principles governing the propagation of oscillations and shock waves in diffusion-driven chain reactions. Methodology. Materials and methods for the research included a computer simulation using MATHCAD 2001i, and comparative analysis of experimental data obtained from reactor experiments. The computational modeling revealed vivid formations of standing wave structures in reactors influenced by feedback mechanisms. Results. The impact of reverse connections in reactors with cylindrical and spherical symmetry significantly contributed to the formation of various standing wave structures of radical concentrations within the reaction zone. It was found that these structures were largely imperceptible visually and could only be observed when the reaction was accompanied by intense light emission. These visual representations served as compelling evidence of the intricate interplay between reaction kinetics and feedback effects. The study emphasized the importance of understanding and predicting the root causes of instabilities, ultimately enhancing the reliability and safety of reactors across various industries. The results demonstrated a correlation between specific feedback mechanisms and the spatial distribution of standing wave structures. Conclusions. The derived computational patterns, as presented in this paper, provide compelling evidence supporting the feasibility of standing wave structure formation within reactors when influenced by feedback mechanisms. The study unveiled the potential for fine-tuning reactor parameters to influence the formation and stability of these structures. The findings represented a significant stride towards a more comprehensive understanding of dynamic regimes in reactors, with implications for reactor design, operation, and safety protocols. The insights garnered from uncovering standing wave structures influenced by feedback mechanisms offered valuable opportunities to optimize reactor design and operational safety, leading to more efficient and sustainable processes
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Shulaeva, Ekaterina A. "Application of Electrodynamic Catalytic Reactors for Intensification of Heat and Mass Exchange Processes of Heterophase Catalysis." WSEAS TRANSACTIONS ON POWER SYSTEMS 17 (March 2, 2022): 37–44. http://dx.doi.org/10.37394/232016.2022.17.4.
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This article discusses a model of an electrodynamic reactor. It is fundamentally different in the way of supplying energy to the reaction zone from the reactors currently in operation in industry. This significantly reduces energy consumption, simplifies process control and increases the efficiency of the reactor. The environmental advantage of the developed reactor is also of great importance. There are no emissions of gases into the atmosphere, which are formed in large quantities during fuel combustion in superheating furnaces, the consumption of water is reduced, which is used only in a closed cycle to cool the microwave generator and circulator as a matching load during its operation. The overall efficiency of the electrodynamic reactor is 1.2 times higher than that of existing industrial ones. A method for calculating thermodynamic processes in electrodynamic reactors is proposed. It allows you to determine the technological parameters of the process to ensure a given temperature distribution and provides the maximum yield of the target reaction products with the minimum possible energy consumption of electromagnetic radiation.
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Chen, Junjie. "Methanol steam reforming for hydrogen production in microchannel reactors." Chemical Engineering Journal Storage 1, no. 4 (April 26, 2022): 1. http://dx.doi.org/10.29103/cejs.v1i4.6176.
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Many attempts have been made to improve heat transfer for thermally integrated microchannel reforming reactors. However, the mechanisms for the effects of design factors on heat transfer characteristics are still not fully understood. This study relates to a thermochemical process for producing hydrogen by the catalytic endothermic reaction of methanol with steam in a thermally integrated microchannel reforming reactor. Computational fluid dynamics simulations are conducted to better understand the consumption, generation, and exchange of thermal energy between endothermic and exothermic processes in the reactor. The effects of wall heat conduction properties and channel dimensions on heat transfer characteristics and reactor performance are investigated. Thermodynamic analysis is performed based on specific enthalpy to better understand the evolution of thermal energy in the reactor. The results indicate that the thermal conductivity of the channel walls is fundamentally important. Materials with high thermal conductivity are preferred for the channel walls. Thermally conductive ceramics and metals are well-suited. Wall materials with poor heat conduction properties degrade the reactor performance. Reaction heat flux profiles are considerably affected by channel dimensions. The peak reaction heat flux increases with the channel dimensions while maintaining the flow rates. The change in specific enthalpy is positive for the exothermic reaction and negative for the endothermic reaction. The change in specific sensible enthalpy is always positive. Design recommendations are made to improve thermal performance for the reactor.
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Chen, Junjie. "Methanol steam reforming for hydrogen production in microchannel reactors." Chemical Engineering Journal Storage 1, no. 4 (April 26, 2022): 1. http://dx.doi.org/10.29103/cejs.v1i4.6176.
Full textAbstract:
Many attempts have been made to improve heat transfer for thermally integrated microchannel reforming reactors. However, the mechanisms for the effects of design factors on heat transfer characteristics are still not fully understood. This study relates to a thermochemical process for producing hydrogen by the catalytic endothermic reaction of methanol with steam in a thermally integrated microchannel reforming reactor. Computational fluid dynamics simulations are conducted to better understand the consumption, generation, and exchange of thermal energy between endothermic and exothermic processes in the reactor. The effects of wall heat conduction properties and channel dimensions on heat transfer characteristics and reactor performance are investigated. Thermodynamic analysis is performed based on specific enthalpy to better understand the evolution of thermal energy in the reactor. The results indicate that the thermal conductivity of the channel walls is fundamentally important. Materials with high thermal conductivity are preferred for the channel walls. Thermally conductive ceramics and metals are well-suited. Wall materials with poor heat conduction properties degrade the reactor performance. Reaction heat flux profiles are considerably affected by channel dimensions. The peak reaction heat flux increases with the channel dimensions while maintaining the flow rates. The change in specific enthalpy is positive for the exothermic reaction and negative for the endothermic reaction. The change in specific sensible enthalpy is always positive. Design recommendations are made to improve thermal performance for the reactor.
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Li, Guochao, Jie Chen, Tao Yang, Jianqi Sun, and Shenglu Yu. "Denitrification with corncob as carbon source and biofilm carriers." Water Science and Technology 65, no. 7 (April 1, 2012): 1238–43. http://dx.doi.org/10.2166/wst.2012.960.
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In this research the agricultural by-product corncob was investigated as a carbon source as well as a biofilm carrier to remove organic matter, expressed as chemical oxygen demand (COD) and nitrate nitrogen (nitrate-N), from wastewater in a batch laboratory reactor. The performance of a reactor with corncob as the carbon source and the biofilm carrier was compared with a control batch reactor with suspended plastic carriers and glucose as the sole carbon source. With 60 vol% of corncob carriers inside the reactor, a soluble COD/N ratio of 4.2 g COD g N−1 was enough for total denitrification, nearly half of the control reactor (9.5 g COD g N−1), at 23 h reaction time. The specific denitrification rate decreased with increasing soluble COD consumption for both reactors. Nitrate and COD removal efficiencies decreased with shorter retention times, with accentuated effects in the reactor. This study suggested corncob as a feasible carbon source and that reaction time was a limiting factor with corncob used as the carbon source for denitrification.
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Mularski, Jakub, and Norbert Modliński. "Impact of Chemistry–Turbulence Interaction Modeling Approach on the CFD Simulations of Entrained Flow Coal Gasification." Energies 13, no. 23 (December 7, 2020): 6467. http://dx.doi.org/10.3390/en13236467.
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This paper examines the impact of different chemistry–turbulence interaction approaches on the accuracy of simulations of coal gasification in entrained flow reactors. Infinitely fast chemistry is compared with the eddy dissipation concept considering the influence of turbulence on chemical reactions. Additionally, ideal plug flow reactor study and perfectly stirred reactor study are carried out to estimate the accuracy of chosen simplified chemical kinetic schemes in comparison with two detailed mechanisms. The most accurate global approach and the detailed one are further implemented in the computational fluid dynamics (CFD) code. Special attention is paid to the water–gas shift reaction, which is found to have the key impact on the final gas composition. Three different reactors are examined: a pilot-scale Mitsubishi Heavy Industries reactor, a laboratory-scale reactor at Brigham Young University and a Conoco-Philips E-gas reactor. The aim of this research was to assess the impact of gas phase reaction model accuracy on simulations of the entrained flow gasification process. The investigation covers the following issues: impact of the choice of gas phase kinetic reactions mechanism as well as influence of the turbulence–chemistry interaction model. The advanced turbulence–chemistry models with the complex kinetic mechanisms showed the best agreement with the experimental data.
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Wang, Boyan, Zhiyuan Wang, Yan Ma, and Yijing Liang. "Heat Transfer Enhancement of Indirect Heat Transfer Reactors for Ca(OH)2/CaO Thermochemical Energy Storage System." Processes 9, no. 7 (June 30, 2021): 1136. http://dx.doi.org/10.3390/pr9071136.
Full textAbstract:
The efficiency of a thermochemical energy storage system can be improved by optimizing the structure of the thermochemical energy storage reactor. We proposed two modified structures for indirect heat transfer thermochemical energy storage reactors for a Ca(OH)2/CaO system to improve their heat transfer performance. Our results showed that improving convective heat transfer offered varying effects on heat transfer performance in different reaction processes. For a half-plate pin fin sinks (HPPFHS) reactor and a plate pin fin sinks (PPFHS) reactor, enhancing the convective heat transfer process could improve the heat transfer performance in the dehydration process for a porosity of 0.5, and the time needed to complete reaction was reduced by around 33% compared with plate fin sinks (PFHS) reactor. As for the hydration process, because heat conduction along the bed dominated heat transfer performance, this method had little effect. Furthermore, we found that enhancing heat conduction along the bed and convective heat transfer had different effects on reaction process at different reaction areas. The HPPFHS reactor had a lower pressure drop along the HTF channel and exorbitant velocity of heat transfer fluid (HTF) was unnecessary. Under the condition of the bed porosity of 0.8, due to the lower thermal conductivity of material, both modified reactor structures had little effect on dehydration. However, because the temperature difference between bed and HFT was bigger, the PPFHS reactor could reduce the time of completing the hydration reaction by 20%. Above all, when planning to modify the reactor structure to improve the heat transfer performance to enhance the reaction process, the heat conditions along the bed, convective heat transfer between HTF and the bed and material parameters should be considered totally.
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Ogijoh Jibrin Yakubu, Olalekan Michael Adeloye, and Princewill Woyinbrakemi Igbagara. "Simulation of packed bed reactors for naphtha reforming unit." International Journal of Engineering Research Updates 3, no. 2 (November 30, 2022): 053–63. http://dx.doi.org/10.53430/ijeru.2022.3.2.0060.
Full textAbstract:
The study focused on the performance evaluation of catalytic naphtha reforming unit via a packed bed reactors arranged in series. Three series arranged packed bed naphtha reforming reactors were developed and simulated using Aspen hysys software and steady state performance models of the packed bed naphtha reforming reactor were developed through the application of the principle of conservation of mass and energy to predict both the yields of theses reactors, their dimensions in terms of length, diameter, height, volume and temperature effects or progressions along the reactors’ length respectively. Three main reaction paths were considered in this research study that include the conversion of naphthenes to aromatics, naphthenes to paraffins and hydrocracking of paraffins. The developed performance models yielded first order ordinary differential equations which were solved using Runge-Kutta fourth order ODE45 solver. The packed bed reactor operating conditions of temperature and pressure are between 4800C and 5200C and 2atm respectively with ninety percent (90%) conversion. The simulated reactor performance model for the three reactors yielded 29.7 m3, 40.78 m3 and 52.33 m3 for reactor volume, catalyst bed height of 11m, 12.98 m, 16 m, and reactor’s diameter of 1.85 m, 2 m and 2.04 m respectively.
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Chaedir, Benitta A., Jundika C. Kurnia, Lianjun Chen, Lishuai Jiang, and Agus P. Sasmito. "Numerical Investigation of Ventilation Air Methane Catalytic Combustion in Circular Straight and Helical Coil Channels with Twisted Tape Insert in Catalytic-Monolith Reactors." Catalysts 10, no. 7 (July 17, 2020): 797. http://dx.doi.org/10.3390/catal10070797.
Full textAbstract:
In a catalytic combustion of ventilation air methane, one of the key factors determining the reactor performance is the geometry of the reactor. It should be designed to provide maximum energy conversion at minimum catalyst usage and operating cost. This numerical study is conducted to investigate the catalytic combustion of ventilation air methane from a gassy underground mine in a circular straight and helical reactor channel with twisted tape insert. A three-dimensional computational fluid dynamics model which considers conservation of mass, momentum, energy, and species together with chemical reactions, and constitutive relations for species properties and reactions kinetics was developed and validated against the previously published data. The effect of several key factors affecting the catalytic combustion performance such as inlet Reynolds number, twisted tape ratio, and reactor length are evaluated to obtain the optimum reactor parameters. For evaluation purpose, the reaction performance of the studied reactors will be compared to the straight reactor without twisted tape which is set as a baseline. The results give a firm confirmation on the superior performance of the reactors with twisted tape insert as compared to those without. In addition, it is found that helical reactors generate higher net power as compared to their respective straight reactor counterpart despite having lower FoM due to larger catalyst area. Interestingly, the higher twisting ratio offers better performance in terms of net power as well as FoM. Overall, the results highlight the potential of twisted tape insert application in catalytic combustion.
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Macků, Lubomír. "Determination of exothermic batch reactor specific model parameters." MATEC Web of Conferences 292 (2019): 01063. http://dx.doi.org/10.1051/matecconf/201929201063.
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An alternative method of determining exothermic reactor model parameters which include first order reaction rate constant is described in this paper. The method is based on known in reactor temperature development and is suitable for processes with changing quality of input substances. This method allows us to evaluate the reaction substances composition change and is also capable of the reaction rate constant (parameters of the Arrhenius equation) determination. Method can be used in exothermic batch or semi- batch reactors running processes based on the first order reaction. An example of such process is given here and the problem is shown on its mathematical model with the help of simulations.
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Liu, Daoyin, Zhonglin Zhang, Yaming Zhuang, and Xiaoping Chen. "Comparison of CFD Simulation and Simplified Modeling of a Fluidized Bed CO2 Capture Reactor." International Journal of Chemical Reactor Engineering 14, no. 1 (February 1, 2016): 133–41. http://dx.doi.org/10.1515/ijcre-2015-0058.
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AbstractCO2 capture using solid sorbents in fluidized bed reactors is a promising technology. The multiphase CFD model is increasingly developed to study the reactors, but it is difficult to model all the realistic details and it requires significant computational time. In this study, both the multiphase CFD model (i.e., CFD-DEM model coupled with reaction) and the simplified reactor models (i.e., plug flow model and bubbling two-phase model) are developed for modeling a fluidized bed CO2 capture reactor. The comparisons are made at different gas velocities from fixed bed to fluidized bed. The DEM based model reveals a detailed view of CO2 adsorption process with particle flow dynamics, based on which the assumptions in the simplified models can be evaluated. The plug flow model predictions generally show similar trends to the DEM model but there are quantitative differences; thus, it can be used to determine the reactor performance limit. The bubbling two-phase model gives better predictions than the plug flow model because the effect of bubbles on the inter-phase mass transfer and reaction is included. In the future, a closer combination of the multiphase CFD simulation and the simplified reactor models will likely be an efficient design method of CO2 capture fluidized bed reactors.
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E, Katsman. "Optimization of Reaction Conducting Efficiency by using the Potential of Column Catalytic Reactor." Petroleum & Petrochemical Engineering Journal 8, no. 1 (January 23, 2024): 1–6. http://dx.doi.org/10.23880/ppej-16000378.
Full textAbstract:
The paper intends for art of running heterogeneous-catalytic chemical reactions with high efficiency using column catalytic reactor with fixed catalyst layer. Described are potential possibilities of this undervalued apparatus to satisfy conditions for selective running of first step in multistep irreversible or reversible reactions in liquid-gas/vapor flow. Minor changes of working regime and construction of the apparatus discussed with the aim to increase the indexes. The idea of these changes is to suppress side reaction steps using due space localization and segregation of reaction participants. As a result, the needed reagents only have possibility for good contact with catalyst and each other. These features may straightly relate to reactionrectification, but realizes much cheaper. The examples chosen for demonstration are Ipatieff’s alkylation of benzene with propylene on “solid acid” and so called “selective hydrogenation” of acetylenes and conjugated dienes.
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Lindeque, Rowan, and John Woodley. "Reactor Selection for Effective Continuous Biocatalytic Production of Pharmaceuticals." Catalysts 9, no. 3 (March 14, 2019): 262. http://dx.doi.org/10.3390/catal9030262.
Full textAbstract:
Enzyme catalyzed reactions are rapidly becoming an invaluable tool for the synthesis of many active pharmaceutical ingredients. These reactions are commonly performed in batch, but continuous biocatalysis is gaining interest in industry because it would allow seamless integration of chemical and enzymatic reaction steps. However, because this is an emerging field, little attention has been paid towards the suitability of different reactor types for continuous biocatalytic reactions. Two types of continuous flow reactor are possible: continuous stirred tank and continuous plug-flow. These reactor types differ in a number of ways, but in this contribution, we focus on residence time distribution and how enzyme kinetics are affected by the unique mass balance of each reactor. For the first time, we present a tool to facilitate reactor selection for continuous biocatalytic production of pharmaceuticals. From this analysis, it was found that plug-flow reactors should generally be the system of choice. However, there are particular cases where they may need to be coupled with a continuous stirred tank reactor or replaced entirely by a series of continuous stirred tank reactors, which can approximate plug-flow behavior. This systematic approach should accelerate the implementation of biocatalysis for continuous pharmaceutical production.
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Mustafa Kamal Pasha, Mustafa Kamal Pasha, Iftikhar Ahmad Iftikhar Ahmad, Jawad Mustafa Jawad Mustafa, and Manabu Kano Manabu Kano. "Modeling of a Nickel-based Fluidized Bed Membrane Reactor for Steam Methane Reforming Process." Journal of the chemical society of pakistan 41, no. 2 (2019): 219. http://dx.doi.org/10.52568/000729/jcsp/41.02.2019.
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Hydrogen being a green fuel is rapidly gaining importance in the energy sector. Steam methane reforming is one of the most industrially important chemical reaction and a key step in the production of high purity hydrogen. Due to inherent deficiencies of conventional reforming reactors, a new concept based on fluidized bed membrane reactor is getting the focus of researchers. In this work, a nickel-based fluidized bed membrane reactor model is developed in the Aspen PLUSand#174; process simulator. A user-defined membrane module is embedded in the Aspen PLUSand#174; through its interface with Microsoftand#174; Excel. Then, a series combination of Gibbs reactors and membrane modules are used to develop a nickel-based fluidized bed membrane reactor. The model developed for nickel-based fluidized bed membrane reactor is compared with palladium-based membrane reactor in terms of methane conversion and hydrogen yield for a given panel of major operating parameters. The simulation results indicated that the model can accurately predict the behavior of a membrane reactor under different operating conditions. In addition, the model can be used to estimate the effective membrane area required for a given rate of hydrogen production.
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Suryono, T. J., Sudarno, S. Santoso, and R. Maerani. "Modelling of FPGA-based Reactor Protection Systems of an Experimental Power Reactor." Journal of Physics: Conference Series 2048, no. 1 (October 1, 2021): 012038. http://dx.doi.org/10.1088/1742-6596/2048/1/012038.
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Abstract The reactor protection system of nuclear power plants including an experimental power reactor which will be built by Indonesia is a safety system that actuates the control rods to be inserted in the reactor core to absorb the neutron to stop the fission reaction and then shut down the reactor (reactor trip). The reactor protection system (RPS) is actuated when the level of signals from the sensors of important components in the reactors deviates from the setpoint determined in the bi-stable processor of the RPS. RPS for the experimental power reactor has 3 redundant channels for reliability and to minimize fake signals from the sensors due to electrical noise. It can be done by selecting the channels in local coincidence logic in the RPS by voting 2 of 3 channels which are eligible to generate actuation signals to trip the reactor. Recently, the RPSs are based on the programmable logic controller (PLC). However, now the trend changes to FPGA-based RPS because of its simplicity and reliability. This paper investigates the model of the FPGA-based RPS for an experimental power reactor and the functionality of each component of the model. The results show that the model can represent the functionality of RPS for the experimental power reactor.
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Caravella, Alessio. "Extended Definition of Conversion and Reaction Extent for a Systematic Development of the Design Equations for Reactor Networks." Processes 12, no. 1 (January 1, 2024): 107. http://dx.doi.org/10.3390/pr12010107.
Full textAbstract:
The aim of this work is to present in a systematic way a novel general methodology to develop the design equations (heat and mass balances) for networks of ideal reactors, that is, Plug-Flow Reactors (PFRs) and Continuous Stirred Tank Reactors (CSTRs). In particular, after introducing the general definition of conversion to be used for reactor networks, several case studies of interest in chemical engineering are presented as topic-examples of application: (i) adiabatic-stage reactors with recycle, (ii) adiabatic-stage reactors with split, (iii) adiabatic-stage reactors intercooled by reactants and (iv) adiabatic-stage reactors with interstage distributed feed. More generally, the presented methodology can also be applied to develop the design equations for complex networks of interconnected reactors, not restricted to those considered in the present work. The motivation behind the present study lies in the fact that, to the best of our knowledge, a systematic development of the design equations of single reactors in reactor networks is currently missing in the open literature as well as in the reference textbooks of chemical reaction engineering and reactor design.
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Vlaev, Serafim D., and Jindřich Zahradník. "Energy effectiveness and working characteristics of different tower reactors for aerated slurry systems." Collection of Czechoslovak Chemical Communications 52, no. 11 (1987): 2624–39. http://dx.doi.org/10.1135/cccc19872624.
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Decisive hydrodynamic and mass transfer characteristics of different types of tower reactors (rotating disc reactor, single and multistage sieve-tray bubble columns, tower reactor with ejector gas distributor) as well as the energy effectiveness of their performance were compared with the purpose to establish a quantitative basis for the qualified choice of the proper reactor type according to demands of specific reaction processes. Selected design parameters included gas and solid phase holdup, kLaL, liquid phase residence time distribution, and axial distribution of the solid phase, the experiments were carried out in a wide range of solid phase concentration (0-20 wt. %) and particle sizes (2.3-280 μm). The experimental results proved that due to their favourable suspension characteristics and operation stability the rotating disc reactors can be advantageously used for slow reaction processes with low demands on the intensity of interfacial gas-liquid contact which can be carried out at low gas flow rates. On the other hand the multistage bubble column reactors proved to be superior devices for transport–controlled reaction processes regarding both the achievable rate of interfacial mass transfer and the overall energetic efficiency of phase contacting.
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Durán Peralta, Héctor Armando, and Luis Fernando Córdoba C. "Stability analysis of a PFTR reactor for a first order kinetic reaction using the Lyapunov functionals." Ingeniería e Investigación 27, no. 1 (January 1, 2007): 115–22. http://dx.doi.org/10.15446/ing.investig.v27n1.14790.
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The stability of reactors having encompassing concentration and temperature parameters, such as continuous flow stirred tank reactors (CSTR), has been widely explored in the literature; however, there are few papers about the stability of tubular reactor having distributed spatial concentration and temperature parameters such as the plow flow tubular reactor (PFTR). This paper analyses the stability of isothermal and non-isothermal PFTR reactors using the Lyapunov functional method. The first order kinetic reaction was selected because one of this paper’s objectives was to apply Lyapunov functionals to stability analysis of distributed parameter reactors (technique used in electrical engineering systems’ stability analysis). The stability analysis revealed asymptotically stable temperature and concentration profiles for isothermal PFTR, non-isothermal PFTR with kinetic constant independent of temperature and adiabatic non-isothermal PFTR. Analysis revealed an asymptotically stability region for the heat exchange reactor and an uncertain region where it may have oscillations.
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Pereira, J. O., E. F. A. Mac Conell, S. Q. Silva, and C. A. L. Chernicharo. "Granular biomass selection in a double-stage biogas collection UASB reactor: effects on SMA, abundance and diversity of the methanogenic population." Water Science and Technology 66, no. 12 (December 1, 2012): 2570–77. http://dx.doi.org/10.2166/wst.2012.483.
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The present work aimed at investigating biomass selection in a pilot-scale double-stage biogas collection (DSBC) upflow anaerobic sludge bed (USAB) reactor treating domestic wastewater. Specific methanogenic activity (SMA) measurements and FISH countings were applied to sludge samples collected during 102 days of operation of the DSBC–UASB and of a control reactor. Results showed that both reactors presented similar SMA values in early stages of operation however the UASB–DSBC reactor showed much higher SMA after day 45, when the biomass was in granular stage. In terms of archaeal abundance, no statistical difference was observed between the reactors. Polymerase chain reaction–denaturing gradient gel electrophoresis (PCR–DGGE) revealed a similar composition of the archaeal communities in the two reactors and during the operational period, mainly constituted by Methanosaeta concilii. The results suggest that cell activity rather than archaeal abundance or diversity drive the methane production in the UASB reactors.
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Silva, Renan Rodrigues de Oliveira, and Mauri Sergio Alves Palma. "Flow synthesis of n-substituted 5-benzylidinethiazolidine-2,4-dione." STUDIES IN ENGINEERING AND EXACT SCIENCES 3, no. 2 (June 1, 2022): 385–402. http://dx.doi.org/10.54021/sesv3n2-006.
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Process intensification based on micro reactor technology allows safe manner and a new pathway to run organic synthesis due to its intrinsic characteristics, and can reduce time-to-market of new drugs. The main objective of this work was to study the batch and flow reaction of five n-substituted 5-benzylidenethiazolidine-2,4-dione heterocyclic intermediates present in the synthesis of glitazone class drugs, in capillary micro reactor. Batch process was conducted with ethanol as solvent at the boiling point and pyrrolidine as promoting base of the reaction. Higher yields were obtained in shorter reaction times in temperatures above solvent boiling point. Also, we evaluated that 3.8 micro reactors in parallel would be necessary to reach the same mean molar flow rate of a 60 mL batch reactor. Kinetic and thermodynamic study indicated that the reaction followed the second-order model and allowed estimating its main thermodynamic parameters. The continuous flow micro reactor proved to be an efficient alternative to the batch process in scaling up the production of Active Pharmaceutical Ingredient intermediates (APIs).
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Li, Penglei, Lingen Chen, Shaojun Xia, and Lei Zhang. "Entropy Generation Rate Minimization for Methanol Synthesis via a CO2 Hydrogenation Reactor." Entropy 21, no. 2 (February 13, 2019): 174. http://dx.doi.org/10.3390/e21020174.
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The methanol synthesis via CO2 hydrogenation (MSCH) reaction is a useful CO2 utilization strategy, and this synthesis path has also been widely applied commercially for many years. In this work the performance of a MSCH reactor with the minimum entropy generation rate (EGR) as the objective function is optimized by using finite time thermodynamic and optimal control theory. The exterior wall temperature (EWR) is taken as the control variable, and the fixed methanol yield and conservation equations are taken as the constraints in the optimization problem. Compared with the reference reactor with a constant EWR, the total EGR of the optimal reactor decreases by 20.5%, and the EGR caused by the heat transfer decreases by 68.8%. In the optimal reactor, the total EGRs mainly distribute in the first 30% reactor length, and the EGRs caused by the chemical reaction accounts for more than 84% of the total EGRs. The selectivity of CH3OH can be enhanced by increasing the inlet molar flow rate of CO, and the CO2 conversion rate can be enhanced by removing H2O from the reaction system. The results obtained herein are in favor of optimal designs of practical tubular MSCH reactors.
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He, Li, Han, Cabassud, and Dahhou. "Development of a Numerical Model for a Compact Intensified Heat-Exchanger/Reactor." Processes 7, no. 7 (July 15, 2019): 454. http://dx.doi.org/10.3390/pr7070454.
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A heat-exchanger/reactor (HEX reactor) is a kind of plug-flow chemical reactor which combines high heat transfer ability and chemical performance. It is a compact reactor designed under the popular trend of process intensification in chemical engineering. Previous studies have investigated its characteristics experimentally. This paper aimed to develop a general numerical model of the HEX reactor for further control and diagnostic use. To achieve this, physical structure and hydrodynamic and thermal performance were studied. A typical exothermic reaction, which was used in experiments, is modeled in detail. Some of the experimental data without reaction were used for estimating the heat transfer coefficient by genetic algorithm. Finally, a non-linear numerical model of 255 calculating modules was developed on the Matlab/Simulink platform. Simulations of this model were done under conditions with and without chemical reactions. Results were compared with reserved experimental data to show its validity and accuracy. Thus, further research such as fault diagnosis and fault-tolerant control of this HEX reactor could be carried out based on this model. The modeling methodology specified in this paper is not restricted, and could also be used for other reactions and other sizes of HEX reactors.
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Chen, Qiang, Mingming Mao, Min Gao, Yongqi Liu, Junrui Shi, and Jia Li. "Design and Performance Investigation of a Compact Catalytic Reactor Integrated with Heat Recuperator." Energies 15, no. 2 (January 9, 2022): 447. http://dx.doi.org/10.3390/en15020447.
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The catalytic combustion has the advantage of lower auto-ignition temperature and helps to expand the combustible limit of lean premixed gas. However, the intake needs to be preheated to certain temperature commonly through an independent heat exchanger. Similar to the principles of non-catalytic RTO combustion, this paper presents a similar approach whereby the combustion chamber is replaced by a catalytic combustion bed. A new catalytic reactor integrated with a heat recuperator is designed to enhance the heat recirculation effect. Using a two-dimensional computational fluid dynamics model, the performance of the reactor is studied. The reaction performances of the traditional and compact reactors are compared and analyzed. Under the same conditions, the compact reactor has better reaction performance and heat recirculation effect, which can effectively decrease the ignition temperature of feed gas. The influences of the inlet velocity, the inlet temperature, the methane concentration, and the thermal conductivity of porous media on the reaction performance of integrated catalytic reactor are studied. The results show that the inlet velocity, inlet temperature, methane concentration, and thermal conductivity of porous media materials have important effects on the reactor performance and heat recirculation effect, and the thermal conductivity of porous media materials has the most obvious influence. Moreover, the reaction performance of multiunit integrated catalytic reactor is studied. The results show that the regenerative effect of multiunit integrated catalytic reactor is further enhanced. This paper is of great significance to the recycling of low calorific value gas energy and relieving energy stress in the future.
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Manassero, Agustina, Orlando Mario Alfano, and María Lucila Satuf. "Degradation of Emerging Pollutants by Photocatalysis: Radiation Modeling and Kinetics in Packed-Bed Reactors." Water 14, no. 22 (November 9, 2022): 3608. http://dx.doi.org/10.3390/w14223608.
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Radiation modeling and kinetics in two different packed-bed reactors filled with TiO2-coated glass rings are presented. The first reactor was cylindrical, irradiated from one end by a 150 W mercury lamp. It was employed to obtain the values of the intrinsic kinetic parameters of the degradation of the emerging contaminant clofibric acid (CA). The expression to represent the kinetics of the pollutant was derived from a proposed reaction scheme, and it includes explicitly the effect of photon absorption rate on the reaction rate. The second reactor was annular, irradiated internally and externally by 40 UV-LED lamps. The kinetic parameters calculated in the first reactor were directly employed to simulate the performance of the second one, without using any adjustable parameter. The Monte Carlo method was applied to solve the radiation models in both reactors. Good agreement was obtained between simulation results and experimental data under different operating conditions, with a percentage root-mean-square error of 4.6%. The kinetic parameters proved to be independent of the irradiation source, reactor geometry, and catalyst film thickness, and can be readily applied to design real scale devices.
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Sutopo, Catur Febriyanto, and Arifin M. Susanto. "Kajian pembentukan peraturan mengenai sistem pendingin reaktor dan sistem terkait untuk reaktor berpendingin gas." Jurnal Pengawasan Tenaga Nuklir 1, no. 2 (December 15, 2021): 11–19. http://dx.doi.org/10.53862/jupeten.v1i2.014.
Full textAbstract:
IN 2021, BAPETEN, AS THE REGULATORY BODY, IS ESTABLISHING A BAPETEN REGULATION REGARDING THE REACTOR COOLANT SYSTEM AND RELATED SYSTEMS, WHICH CURRENTLY ARE NOT YET AVAILABLE. Therefore, it is crucial to establish the BAPETEN Regulation. Based on the reasons, before setting the BAPETEN Regulation, it is necessary to conduct a study that is expected to provide a more comprehensive description and provide recommendations on what things need to be regulated in the BAPETEN Regulation, especially for gas-cooled reactors. The method used in this study is a literature study from various relevant references. The result of this study is that it is essential to require a capacity of the ultimate heat sink, including the spent nuclear fuel storage pool and a minimum period of the ability of the top heat sink in the accident analysis if the decay heat in the storage pool and the residual heat in the reactor core fail simultaneously. On the other hand, it is also necessary to require a margin of uncertainty to evaluate a situation and take corrective action. Likewise, independent and redundant access to the ultimate heat sink is needed to increase reliability. As for gas-cooled reactors, it is required to adapt the terms used. In addition, it is necessary to determine the appropriate definition because some of the terms used in water-cooled reactors have the same terms as gas-cooled reactors but have different functions. Keywords: Regulatory assessment, coolant system, related systems, gas-cooled reactors
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Kalyuzhnyi, Sergey, and Vyacheslav Fedorovich. "Integrated mathematical model of UASB reactor for competition between sulphate reduction and methanogenesis." Water Science and Technology 36, no. 6-7 (September 1, 1997): 201–8. http://dx.doi.org/10.2166/wst.1997.0592.
Full textAbstract:
The existing mathematical models of anaerobic treatment processes were mainly developed for ideally mixed reactors with no concentration gradients on substrates, intermediates, products and bacteria inside the reactor. But for conventional UASB reactors with low upward velocity, the distribution of these components along the reactor height is very far from uniform. This paper presents an integrated mathematical model of the functioning of UASB reactor taking into account this non-uniformity as well as multiple-reaction stoichiometry and kinetics. In general, our integrated model includes the following blocks: a) kinetic block, including the growth and metabolism of acidogenic, acetogenic, methanogenic and sulphate-reducing bacteria; b) physico-chemical block, for the calculation of pH in each compartment of the liquid phase; c) hydrodynamic block, describing liquid flow as well as the transport and distribution of the components along the reactor height; d) transfer block, describing a mass transfer of gaseous components from the liquid to gas phase. This model was calibrated to some experimental studies of the functioning of UASB reactors made by in 1994. Hypothetical computer simulations are presented to illustrate the influence of different factors (recycle number, hydraulic retention time, quality of seed sludge, SO42−:COD ratio etc.) on the operation performance of UASB reactor.
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Jiang, Junan, Ning Yang, Hanyang Liu, Jianxin Tang, Chenfeng Wang, Rijie Wang, and Xiaoxia Yang. "Modification of Meso-Micromixing Interaction Reaction Model in Continuous Reactors." Processes 11, no. 5 (May 22, 2023): 1576. http://dx.doi.org/10.3390/pr11051576.
Full textAbstract:
The yields of chemical reactions are highly dependent on the mixing pattern between reactants. Herein, we report the modification of a meso-micromixing interaction reaction model which is applied in batch reactors by leveraging the flow characteristics in the continuous reactors. Both experimental and model-predicted yields were compared using the classical Villermaux–Dushman method in a self-designed split and recombination reactor. This modified model significantly reduced the error in predicted product yields from approximately 15% to within 3%, compared to a model containing the micromixing term only. The effects of flow rates and reactor structure parameters on mixing performance were analyzed. We found that increasing flow rates and the degree of twist in the mixing element’s grooves, as well as decreasing the cross-sectional area of grooves, improved mixing performance. The optimization of reactor flow rates and structural parameters was achieved by combining Gaussian process regression and Bayesian optimization with the modified model. This approach provided higher target product yields for consecutive reactions, while simultaneously achieving a lower pressure drop in the reactor. Corresponding combinations of reactor parameters were also identified during this process. Our modified model-based optimization methodology can be applied to a diversity of reactors, serving as a reference for the selection of their structure and operational parameters.
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Truong Duc, Duc, Huy Nguyen Trung, and Thang Le Minh. "Improving the catalytic activity of Au/SiO2 catalyst in the directly conversion of CO2, C2H4 and H2 using a new dual-reactor concept." Vietnam Journal of Catalysis and Adsorption 9, no. 1 (April 30, 2020): 81–87. http://dx.doi.org/10.51316/jca.2020.013.
Full textAbstract:
Directly conversion of CO2 to propanol using C2H4 and H2 had succeeded over Au/SiO2 catalyst in one reactor mode. However, application of new dual-reactor concept enhaned the catalytic activity strongly by using two saparated reactors. To this details, a first reactor is used to convert CO2 to CO through the reverse water gas shift (RWGS) reaction, consecutive hydroformylation of C2H4 with resulting CO and H2 to propanal and finally the hydrogenation of propanal to propanol takes place in a second reactor at a different temperature. The selectivity to oxo products (propanol and propanal) increased from 15% up to 60% while yeild of oxo products improved from 7% to 15% in comparison with the previous publications.
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Asano, Shusaku, Yosuke Muranaka, Taisuke Maki, Koki Ikeda, and Kazuhiro Mae. "Kinetic Modeling of an Enzyme Membrane Reactor for the Selective Production of Oligosaccharides." Fermentation 8, no. 12 (December 2, 2022): 701. http://dx.doi.org/10.3390/fermentation8120701.
Full textAbstract:
An enzyme membrane reactor is an attractive tool for producing oligosaccharides from biomass-based polysaccharides. However, kinetic modeling and reactor design based on the rate equations have rarely been reported for enzyme membrane reactors because of the difficulty in tracing the depolymerization process. In this study, a simplified reaction model based on Michaelis–Menten-type kinetics has been built to simulate the enzyme membrane reactor. Ramping various species into reactant, target, and byproduct worked well for discussing reactor performance. The use of a membrane with a molecular weight cut-off (MWCO) of 10 kDa with continuous feeding of the reactant was suggested for the efficient production of chitosan hexamer and pentamer by enzymatic hydrolysis of chitosan.
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Zhao, Dong Mei, and Xue Peng Liu. "The Simulation of Poly Reactors and Chain-Analyzing Method in Material Engineering." Advanced Materials Research 583 (October 2012): 366–69. http://dx.doi.org/10.4028/www.scientific.net/amr.583.366.
Full textAbstract:
One or a series of continuous stirred tank reactors (CSTR) is adopted in material engineering. The first esterification reactor and the final stage polyeondensation reactor are very significant，which operation affect the quality of output directly. The influence of operational variables is discussed separately. Toward the final stage Polycondensation reactor，it is regarded as ten CSTR s and obtain approximatively the figure of each component along with shaft. In the“chain-analyzing method”， Polymer is regarded as many chains. It is not the Polymer but the chain that is regarded as the component of the system. so the model treats the calculation of the reaction rates，the mass balance and the heat balance in the Polymer reaction as easily as in the reaction of low-molecular-weight substances