scholarly journals Stochastic modeling of microstructure of homopolymers and copolymers in batch reactor

2020 ◽  
Vol 9 (2) ◽  
pp. e04921930
Author(s):  
Matheus Dias Carvalho ◽  
Jorge David Alguiar Beliido ◽  
Antonio Marcos de Oliveira Siqueira ◽  
Júlio Cesar Costa Campos
Keyword(s):  
Stochastic Modeling ◽  
Chemical Reactions ◽  
Batch Reactor ◽  
Polymer Chains ◽  
Stochastic Methods ◽  
Batch Reactors ◽  
Straight Chain ◽  
Reaction Conditions ◽  
C Language ◽  
Methyl Styrene

Find the microstructure of the product generated in a reaction of polymerization is desirable from a material science standpoint, due to the association between the microstructure and the physical properties. For the science of this fact, this paper aims to use stochastic modeling to obtain the microstructure and key information from a set of polymer chains generated during a reaction. From this data, the present article contributes to the minimization of experimental expenses, besides the saving of time, since no experiments are necessary to discover the characteristics of the polymer obtained under certain reaction conditions. This information cannot be found by other usual methodologies for modeling chemical reactions, such as the deterministic form. Also, from a given desired structure, the initial concentration and temperature conditions for forming that product can be obtained. This study was conducted based on Monte Carlo stochastic methods, by which we seek to replicate the randomness present in chemical reactions. The algorithm created in C ++ language determines the variation of the number of molecules of each species with time, besides the chemical composition, the sequence of mere and size of the generated chains. This approach applies to straight-chain homopolymerizations and copolymerizations. In this paper, we studied the polymerization in styrene batch reactors to form polystyrene, in addition to the copolymerization of styrene with alpha-methyl styrene. These simulations were characterized by forming chains with small blocks of monomers.

A simulation apparatus for the experimental study of batch reactor control methods

1986 ◽  
Vol 51 (6) ◽  
pp. 1259-1267
Author(s):  
Josef Horák ◽  
Petr Beránek
Keyword(s):  
Experimental Study ◽  
Closed Loop ◽  
Dynamic Properties ◽  
Batch Reactor ◽  
Exothermic Reaction ◽  
Electric Heating ◽  
Batch Reactors ◽  
Exchange Area ◽  
The Stability ◽  
Methods Of Control

A simulation apparatus for the experimental study of the methods of control of batch reactors is devised. In this apparatus, the production of heat by an exothermic reaction is replaced by electric heating controlled by a computer in a closed loop; the reactor is cooled with an external cooler whose dynamic properties can be varied while keeping the heat exchange area constant. The effect of the cooler geometry on its dynamic properties is investigated and the effect of the cooler inertia on the stability and safety of the on-off temperature control in the unstable pseudostationary state is examined.

scholarly journals Minimization of N2O Emission through Intermittent Aeration in a Sequencing Batch Reactor (SBR): Main Behavior and Mechanism

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 210
Author(s):  
Tang Liu ◽  
Shufeng Liu ◽  
Shishi He ◽  
Zhichao Tian ◽  
Maosheng Zheng
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Batch Reactor ◽  
Quantitative Polymerase Chain Reaction ◽  
N2o Emission ◽  
Ammonia Oxidizer ◽  
Batch Reactors ◽  
Intermittent Aeration ◽  
Major Pathway ◽  
Nitrifier Denitrification

To explore the main behavior and mechanism of minimizing nitrous oxide (N2O) emission through intermittent aeration during wastewater treatment, two lab-scale sequencing batch reactors operated at intermittently aerated mode (SBR1), and continuously aerated mode (SBR2) were established. Compared with SBR2, the intermittently aerated SBR1 reached not only a higher total nitrogen removal efficiency (averaged 93.5%) but also a lower N2O-emission factor (0.01–0.53% of influent ammonia), in which short-cut nitrification and denitrification were promoted. Moreover, less accumulation and consumption of polyhydroxyalkanoates, a potential endogenous carbon source promoting N2O emission, were observed in SBR1. Batch experiments revealed that nitrifier denitrification was the major pathway generating N2O while heterotrophic denitrification played as a sink of N2O, and SBR1 embraced a larger N2O-mitigating capability. Finally, quantitative polymerase chain reaction results suggested that the abundant complete ammonia oxidizer (comammox) elevated in the intermittently aerated environment played a potential role in avoiding N2O generation during wastewater treatment. This work provides an in-depth insight into the utilization of proper management of intermittent aeration to control N2O emission from wastewater treatment plants.

scholarly journals Visible Light Photochemical Reactions for Nucleic Acid-Based Technologies

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 556
Author(s):  
Bonwoo Koo ◽  
Haneul Yoo ◽  
Ho Jeong Choi ◽  
Min Kim ◽  
Cheoljae Kim ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Visible Light ◽  
Chemical Reactions ◽  
Chemical Biology ◽  
Photochemical Reactions ◽  
Reaction Conditions ◽  
Promising Tool ◽  
Recent Developments ◽  
Visible Light Driven

The expanding scope of chemical reactions applied to nucleic acids has diversified the design of nucleic acid-based technologies that are essential to medicinal chemistry and chemical biology. Among chemical reactions, visible light photochemical reaction is considered a promising tool that can be used for the manipulations of nucleic acids owing to its advantages, such as mild reaction conditions and ease of the reaction process. Of late, inspired by the development of visible light-absorbing molecules and photocatalysts, visible light-driven photochemical reactions have been used to conduct various molecular manipulations, such as the cleavage or ligation of nucleic acids and other molecules as well as the synthesis of functional molecules. In this review, we describe the recent developments (from 2010) in visible light photochemical reactions involving nucleic acids and their applications in the design of nucleic acid-based technologies including DNA photocleaving, DNA photoligation, nucleic acid sensors, the release of functional molecules, and DNA-encoded libraries.

scholarly journals Evaluation of the Bioelectrochemical Approach and Different Electron Donors for Biological Trichloroethylene Reductive Dichlorination

Toxics ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 37
Author(s):  
Edoardo Dell’Armi ◽  
Marta Maria Rossi ◽  
Lucia Taverna ◽  
Marco Petrangeli Papini ◽  
Marco Zeppilli
Keyword(s):  
Reductive Dechlorination ◽  
Molecular Hydrogen ◽  
Batch Reactor ◽  
Electron Donors ◽  
Utilization Efficiency ◽  
Batch Reactors ◽  
Organic Substrates ◽  
Chlorinated Aliphatic Hydrocarbons ◽  
Low Solubility ◽  
Dechlorination Reaction

Trichloroethylene (TCE) and more in general chlorinated aliphatic hydrocarbons (CAHs) can be removed from a contaminated matrix thanks to microorganisms able to perform the reductive dechlorination reaction (RD). Due to the lack of electron donors in the contaminated matrix, CAHs’ reductive dechlorination can be stimulated by fermentable organic substrates, which slowly release molecular hydrogen through their fermentation. In this paper, three different electron donors constituted by lactate, hydrogen, and a biocathode of a bioelectrochemical cell have been studied in TCE dechlorination batch experiments. The batch reactors evaluated in terms of reductive dechlorination rate and utilization efficiency of the electron donor reported that the bio-electrochemical system (BES) showed a lower RD rate with respect of lactate reactor (51 ± 9 µeq/d compared to 98 ± 4 µeq/d), while the direct utilization of molecular hydrogen gave a significantly lower RD rate (19 ± 8 µeq/d), due to hydrogen low solubility in liquid media. The study also gives a comparative evaluation of the different electron donors showing the capability of the bioelectrochemical system to reach comparable efficiencies with a fermentable substrate without the use of other chemicals, 10.7 ± 3.3% for BES with respect of 3.5 ± 0.2% for the lactate-fed batch reactor. This study shows the BES capability of being an alternative at classic remediation approaches.

scholarly journals A Novel Approach of Bioesters Synthesis through Different Technologies by Highlighting the Lowest Energetic Consumption One

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4190
Author(s):  
Simona Popa ◽  
Andra Tamas ◽  
Vasile Simulescu ◽  
Dorin Jurcau ◽  
Sorina Boran ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Energy Consumption ◽  
Bubble Column ◽  
Batch Reactor ◽  
Reaction Times ◽  
Fatty Acid Esters ◽  
Bubble Column Reactor ◽  
Batch Reactors ◽  
Novel Approach ◽  
Microwave Reactors

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.

scholarly journals Anaerobic Digestion Process for the Treatment of Sisdole Landfill Leachate in Nepal

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Bikash Adhikari ◽  
Shilpa Koirala
Keyword(s):  
Anaerobic Digestion ◽  
Removal Efficiency ◽  
Landfill Leachate ◽  
Waste Treatment ◽  
Batch Reactor ◽  
Batch Reactors ◽  
Leachate Treatment ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Solids Concentration

Along with the population, organic waste has been rising significantly in recent years. The resulting uncontrollable waste loads and conventional methods of waste treatment have begun to cause chaos at the landfill sites. This study evaluates the performance of an anaerobic digestion process using batch reactors for the treatment of landfill leachate collected from the Sisdole landfill site in Nuwakot, Nepal. A lab-scale anaerobic batch reactor was set up in Kathmandu University, Nepal. Using an anaerobic digestion process, COD values of the leachate decreased from 2230 mg/l to 1125 mg/l (removal efficiency of ~50%), whereas total solids concentration decreased from 1925 to 925 mg/L under a retention time of 10 days. In addition, Monod’s model was established to design an Anaerobic Sequential Batch Reactor to achieve better performance, resulting in 85% removal efficiency for the leachate treatment. Overall, this study analyzed the anaerobic digestion process on the landfill leachate of Sisdole, and modeled the process to identify the conditions required for increasing the efficiency of treatment of Sisdole landfill leachate.

Performance Analysis of Three Controllers for the Polymerisation of Styrene in a Batch Reactor

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
Emmanuel E Ekpo ◽  
Iqbal M Mujtaba
Keyword(s):  
Performance Analysis ◽  
Batch Reactor ◽  
Monomer Conversion ◽  
Average Chain Length ◽  
Generic Model ◽  
Batch Reactors ◽  
Dynamic Optimisation ◽  
Model Control ◽  
Simple Kinetic Model ◽  
Generic Model Control

The performance analysis of three advanced non linear controllers is the main focus of this paper. All three controllers are applied for the control of a batch polymerisation reactor which is defined by a very simple kinetic model for the polymerisation of styrene. This simple set of equations describing the polymerisation process is first solved using the sequential strategy i.e. Control Vector Parameterisation (CVP) technique within gPROMS to find optimal initial initiator concentrations and the reactor temperature trajectory necessary to yield desired polymer molecular properties (defined here as fixed values of monomer conversion and number average chain length) in minimum time. The sequential solution strategy has had limited application in solving optimisation problems for polymerisation in batch reactors, most researchers instead employing the Pontryagin's Maximum Principle (PMP) to solve optimal control problems involving these systems.The temperature trajectory obtained from the dynamic optimisation is used as the setpoint to be tracked by the three controllers: Dual Mode control with PID, which is representative of industrial practice, Generic Model Control (GMC) with Neural Networks as online heat release estimator, and Direct Inverse Control (DIC). Published work on the last two controllers as applied to the control of a batch polymerisation reactor is absent from the literature.When the performances of the different controllers are evaluated, it is seen that the GMC-NN controller performs better than the other two for the system under consideration.

Kinetics of Glycerol Biotransformation to Dihydroxyacetone by Immobilized Gluconobacter oxydans and Effect of Reaction Conditions

2007 ◽  
Vol 72 (9) ◽  
pp. 1269-1283 ◽  
Author(s):  
Jiří Raška ◽  
František Skopal ◽  
Karel Komers ◽  
Jaroslav Machek
Keyword(s):  
Yeast Extract ◽  
Batch Reactor ◽  
Gluconobacter Oxydans ◽  
Poly Vinyl Alcohol ◽  
Glycerol Concentration ◽  
Reaction Conditions ◽  
Extract Concentration ◽  
Autocatalytic Model ◽  
Kinetics Of ◽  
Reaction Schemes

Biotransformation of glycerol to 1,3-dihydroxyacetone was carried out in an isothermal isochoric batch reactor with Gluconobacter oxydans immobilized in poly(vinyl alcohol) gel capsules. The reaction course was described with a three-step kinetic model. Two reaction schemes were proposed and compared with 8 kinetic experiments at 25 °C. The experimental dependences of glycerol and dihydroxyacetone concentrations on reaction time were simulated very well by the autocatalytic model. The effects of reaction temperature and initial concentrations of yeast extract and glycerol were studied. Temperature 25-30 °C, initial yeast extract concentration 2-4 g l-1 and initial glycerol concentration 20-50 g l-1 were found as optimal. The determined rate constants can be used to advantage for industrial production of dihydroxyacetone from glycerol.

Intensification of the Production of 2-Ethyl-Hexyl Acrylate: Batch Kinetics and Reactive Distillation

2018 ◽  
Vol 16 (7) ◽  
Author(s):  
Vivek D. Talnikar ◽  
Onkar A. Deorukhkar ◽  
Amit Katariya ◽  
Yogesh S. Mahajan
Keyword(s):  
Kinetic Model ◽  
Acrylic Acid ◽  
Process Development ◽  
Reactive Distillation ◽  
Batch Reactor ◽  
Process Intensification ◽  
Complete Conversion ◽  
Reaction Conditions ◽  
Batch Mode ◽  
Batch Kinetics

Abstract The reaction of acrylic acid and 2-ethyl-1 hexanol was explored in this work with the intent of process intensification. In order to assess the effect of important parameters on the course of reaction, this work initially conducted batch reactor experiments. Reaction conditions in the batch reactor for a specific conversion (~ 30 %) were obtained. A kinetic model was then obtained through regression to arrive at a rate expression that is later used in process development. Experiments were performed in the reactive distillation (RD) environment in batch mode, which showed substantial increase in conversion (~ 80 %) indicating the applicability of RD. Further, this work performed simulation in the RD environment to assess process intensification. Simulations show that it is possible to obtain complete conversion of the acid.

Reactor Design for Complex Reactions

2001 ◽  
Author(s):  
L. K. Doraiswamy
Keyword(s):  
Batch Reactor ◽  
Plug Flow ◽  
Reaction Network ◽  
Reactor Design ◽  
Batch Reactors ◽  
Complex Reaction ◽  
Mixed Flow ◽  
Flow Reactors ◽  
Design Procedures ◽  
Reactor Types

Procedures were formulated in Chapter 5 for treating complex reactions. We now turn to the design of reactors for such reactions. Continuing with the ethylation reaction, we consider the following reactor types for which design procedures were formulated earlier in Chapter 4 for simple reactions: batch reactors, continuous stirred reactors (or mixed-flow reactors), and plug-flow reactors. However, we use the following less formal nomenclature: A = aniline, B = ethanol, C = monoethyaniline, D = water, E = diethylaniline, F = diethyl ether, and G = ethylene. The four independent reactions then become Using this set of equations as the basis, we now formulate design equations for various reactor types. Detailed expositions of the theory are presented in a number of books, in particular Aris (1965, 1969) and Nauman (1987). Consider a reaction network consisting of N components and M reactions. A set of N ordinary differential equations, one for each component, would be necessary to mathematically describe this system. They may be concisely expressed in the form of Equation 5.5 (Chapter 5), or . . . d(cV)/dt = vrV (11.1) . . . The use of this equation in developing batch reactor equations for a typical complex reaction is illustrated in Example 11.1.

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