Flow-Through PolyHIPE Silver-Based Catalytic Reactor

Catalytic reactors performing continuously are an important step towards more efficient and controllable processes compared to the batch operation mode. For this purpose, homogenous high internal phase emulsion polymer materials with an immobilized silver catalyst were prepared and used as a continuous plug flow reactor. Porous material with epoxide groups was functionalized to bear aldehyde groups which were used to reduce silver ions using Tollens reagent. Investigation of various parameters revealed that the mass of deposited silver depends on the aldehyde concentration as well as the composition of Tollens reagent. Nanoparticles formed on the pore surface showed high crystallinity with a cuboctahedra crystal shape and highly uniform surface coverage. The example of the 4-nitrophenol catalytic reduction in a continuous process was studied and demonstrated to be dependent on the mass of deposited silver. Furthermore, productivity increased with the volumetric silver density and flow rate, and it was preserved during prolonged usage and storage.

Download Full-text

Deactivation of Cu/SSZ-13 NH3-SCR Catalyst by Exposure to CO, H2, and C3H6

Catalysts ◽

10.3390/catal9110929 ◽

2019 ◽

Vol 9 (11) ◽

pp. 929 ◽

Cited By ~ 1

Author(s):

Auvray ◽

Mihai ◽

Lundberg ◽

Olsson

Keyword(s):

Flow Reactor ◽

Catalytic Reduction ◽

Plug Flow ◽

Acid Sites ◽

Drift Spectroscopy ◽

Scr Catalyst ◽

Nh3 Scr ◽

Scr Catalysts ◽

Nh3 Oxidation ◽

Diffuse Reflectance Infrared

Lean nitric oxide (NOx)-trap (LNT) and selective catalytic reduction (SCR) are efficient systems for the abatement of NOx. The combination of LNT and SCR catalysts improves overall NOx removal, but there is a risk that the SCR catalyst will be exposed to high temperatures and rich exhaust during the LNTs sulfur regeneration. Therefore, the effect of exposure to various rich conditions and temperatures on the subsequent SCR activity of a Cu-exchanged chabazite catalyst was studied. CO, H2, C3H6, and the combination of CO + H2 were used to simulate rich conditions. Aging was performed at 800 °C, 700 °C, and, in the case of CO, 600 °C, in a plug-flow reactor. Investigation of the nature of Cu sites was performed with NH3-temperature-programed desorption (TPD) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) of probe molecules (NH3 and NO). The combination of CO and H2 was especially detrimental to SCR activity and to NH3 oxidation. Rich aging with low reductant concentrations resulted in a significantly larger deactivation compared to lean conditions. Aging in CO at 800 °C caused SCR deactivation but promoted high-temperature NH3 oxidation. Rich conditions greatly enhanced the loss of Brønsted and Lewis acid sites at 800 °C, indicating dealumination and Cu migration. However, at 700 °C, mainly Brønsted sites disappeared during aging. DRIFT spectroscopy analysis revealed that CO aging modified the Cu2+/CuOH+ ratio in favor of the monovalent CuOH+ species, as opposed to lean aging. To summarize, we propose that the reason for the increased deactivation observed for mild rich conditions is the transformation of the Cu species from Z2Cu to ZCuOH, possibly in combination with the formation of Cu clusters.

Download Full-text

Experimental and Modeling Study of CO-Selective Catalytic Reduction of NO Over Perovskite-Type Nanocatalysts

Periodica Polytechnica Chemical Engineering ◽

10.3311/ppch.13767 ◽

2019 ◽

Vol 64 (1) ◽

pp. 46-53 ◽

Cited By ~ 1

Author(s):

Shiva Abedi ◽

Aligholi Niaei ◽

Najaf Namjou ◽

Darioush Salari ◽

Ali Tarjomannejad ◽

...

Keyword(s):

Kinetic Model ◽

Selective Catalytic Reduction ◽

Flow Reactor ◽

Catalytic Reduction ◽

Sol Gel ◽

Plug Flow ◽

Correlation Coefficients ◽

Reduction Of No ◽

Proposed Model ◽

Perovskite Type

In this work LaFeO3, LaFe0.7Mn0.3O3 and LaMn0.7Fe0.3O3 nanocatalysts with perovskite structures have been synthesized by sol-gel method. The selective catalytic reduction of NO with CO (CO-SCR) using synthesized nanocatalysts was investigated in a plug flow reactor. The kinetics of CO-SCR process was studied and three kinetic models were used to describe the behavior of the system, including power low model (PLM), kinetic model 1 (KM1) and kinetic model 2 (KM2). The KM1 was the best model with correlation coefficients of 0.9924, 0.9911 and 0.9902 and the sum of squared errors of 0.0504, 0.0488 and 0.0397, for LaFeO3, LaFe0.7Mn0.3O3 and LaFe0.3Mn0.7O3 catalysts, respectively. By comparing experimental results with the predicted results of the KM1, it was found that the proposed model can predict the performance of catalysts in the CO-SCR process with considerable precision. The structure and morphology of perovskite-type oxides were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively.

Download Full-text

A Modelling Approach of the Catalytic Oxidation of Volatile Organic Compounds in the SCR-DeNOx Monolithic Reactor

Revista de Chimie ◽

10.37358/rc.20.7.8227 ◽

2020 ◽

Vol 71 (7) ◽

pp. 79-87

Author(s):

Liliana Lazar ◽

Heinz Koeser ◽

Ioana Fechete ◽

Ion Balasanian

Keyword(s):

Volatile Organic Compounds ◽

Catalytic Oxidation ◽

Organic Compounds ◽

Flow Reactor ◽

Pollution Abatement ◽

Plug Flow ◽

Integrated Approach ◽

Design Development ◽

Catalytic Reactors ◽

Volatile Organic

Monolithic reactors play an important role in the integrated approach to environmental protection, especially in air pollution abatement. Mathematical modelling of catalytic reactors has become a key procedure in the design, development and optimisation of many industrial processes. The objective of this study was the modelling and simulation of the catalytic oxidation of volatile organic compounds by a commercial V2O5-WO3/TiO2 honeycomb catalyst, specific for the SCR-DeNOx process in high-dust flue gases from stationary incineration. The mathematical model is developed for the numerical simulation of a tubular plug flow reactor, using mass balance equation to predict results for benzene conversion under isothermal conditions.

Download Full-text

A stochastic model for two-station hydraulics exhibiting transient impact

Water Science & Technology ◽

10.2166/wst.1997.0156 ◽

1997 ◽

Vol 36 (5) ◽

pp. 19-26 ◽

Cited By ~ 1

Author(s):

J. L. Jacobsen ◽

H. Madsen ◽

P. Harremoès

Keyword(s):

Parameter Estimation ◽

Flow Reactor ◽

Deterministic Model ◽

Plug Flow ◽

Stochastic Methods ◽

Sewer System ◽

Statistical Tool ◽

Water Level Variation ◽

Deterministic Description ◽

Linear Reservoir

The objective of the paper is to interpret data on water level variation in a river affected by overflow from a sewer system during rain. The simplest possible, hydraulic description is combined with stochastic methods for data analysis and model parameter estimation. This combination of deterministic and stochastic interpretation is called grey box modelling. As a deterministic description the linear reservoir approximation is used. A series of linear reservoirs in sufficient number will approximate a plug flow reactor. The choice of number is an empirical expression of the longitudinal dispersion in the river. This approximation is expected to be a sufficiently good approximation as a tool for the ultimate aim: the description of pollutant transport in the river. The grey box modelling involves a statistical tool for estimation of the parameters in the deterministic model. The advantage is that the parameters have physical meaning, as opposed to many other statistically estimated, empirical parameters. The identifiability of each parameter, the uncertainty of the parameter estimation and the overall uncertainty of the simulation are determined.

Download Full-text

Efficient Production of Light Olefin Based on Methanol Dehydration: Simulation and Design Improvement

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207323666200720104614 ◽

2020 ◽

Vol 23 ◽

Author(s):

S. Majid Abdoli ◽

Mahsa Kianinia

Keyword(s):

Dimethyl Ether ◽

Flow Reactor ◽

New Technology ◽

Plug Flow ◽

Light Olefins ◽

Efficient Production ◽

Actual Process ◽

Light Olefin ◽

Aspen Hysys ◽

Improved Design

Background: Ethylene, propylene, and butylene as light olefins are the most important intermediates in the petrochemical industry worldwide. Methanol to olefins (MTO) process is a new technology based on catalytic cracking to produce ethylene and propylene from methanol. Aims and Objective: This study aims to simulate the process of producing ethylene from methanol by using Aspen HYSYS software from the initial design to the improved design. Methods: Ethylene is produced in a two-step reaction. In an equilibrium reactor, the methanol is converted to dimethyl ether by an equilibrium reaction. The conversion of the produced dimethyl ether to ethylene is done in a conversion reactor. Changes have been made to improve the conditions and get closer to the actual process design done in the industry. The plug flow reactor has been replaced by the equilibrium reactor, and the distillation column was employed to separate the dimethyl ether produced from the reactor. Result and Conclusion: The effect of the various parameters on the ethylene production was investigated. Eventually, ethylene is

Download Full-text

PLUG-FLOW REACTOR-BASED ANTIBIOTIC AND NUTRIENT REMOVAL BY VETIVER GRASS (CHRYSOPOGON ZIZANIOIDES)

10.1130/abs/2020am-358630 ◽

2020 ◽

Author(s):

Dibyendu Sarkar ◽

◽

Saumik Panja ◽

Rupali Datta

Keyword(s):

Nutrient Removal ◽

Flow Reactor ◽

Plug Flow ◽

Plug Flow Reactor ◽

Vetiver Grass ◽

Chrysopogon Zizanioides

Download Full-text

Enhancing Fenton-like oxidation of crystal violet over Fe/ZSM-5 in a plug flow reactor

Reaction Kinetics Mechanisms and Catalysis ◽

10.1007/s11144-021-02001-z ◽

2021 ◽

Author(s):

Sara Modarresi-Motlagh ◽

Fatemeh Bahadori ◽

Mohammad Ghadiri ◽

Arash Afghan

Keyword(s):

Crystal Violet ◽

Flow Reactor ◽

Plug Flow ◽

Plug Flow Reactor

Download Full-text

Effect of Aspect Ratio on the Mixing Performance in the Kenics Static Mixer

Processes ◽

10.3390/pr9030464 ◽

2021 ◽

Vol 9 (3) ◽

pp. 464

Author(s):

Xingren Jiang ◽

Ning Yang ◽

Rijie Wang

Keyword(s):

Pharmaceutical Industry ◽

Aspect Ratio ◽

Flow Reactor ◽

Mixing Time ◽

Continuous Process ◽

Scale Up ◽

Influence Factors ◽

Continuous Manufacturing ◽

Static Mixer ◽

Mixing Performance

Continuous manufacturing has received increasing interest because of the advantages of intrinsic safety and enhanced mass transfer in the pharmaceutical industry. However, the difficulty for scale-up has limited the application of continuous manufacturing for a long time. Recently, the tubular flow reactor equipped with the Kenics static mixer appears to be a solution for the continuous process scale-up. Although many influence factors on the mixing performance in the Kenics static mixer have been investigated, little research has been carried out on the aspect ratio. In this study, we used the coefficient of variation as the mixing evaluation index to investigate the effect of the aspect ratio (0.2–2) on the Kenics static mixer’s mixing performance. The results indicate that a low aspect ratio helps obtain a shorter mixing time and mixer length. This study suggests that adjusting the aspect ratio of the Kenics static mixer can be a new strategy for the scale-up of a continuous process in the pharmaceutical industry.

Download Full-text

The Effect of Mg and Zn Dopants on Pt/Al2O3 for the Dehydrogenation of Perhydrodibenzyltoluene

Catalysts ◽

10.3390/catal11040490 ◽

2021 ◽

Vol 11 (4) ◽

pp. 490

Author(s):

Rudaviro Garidzirai ◽

Phillimon Modisha ◽

Innocent Shuro ◽

Jacobus Visagie ◽

Pieter van Helden ◽

...

Keyword(s):

Electron Microscopy ◽

Inductively Coupled Plasma ◽

Flow Reactor ◽

Plug Flow ◽

Optical Emission ◽

Catalytic Performance ◽

Emission Spectrometry ◽

Hydrogen Yield ◽

X Ray ◽

Temperature Programmed

The effects of Mg and Zn dopants on the catalytic performance of Pt/Al2O3 catalyst were investigated for dehydrogenation of perhydrodibenzyltoluene (H18-DBT) as a liquid organic hydrogen carrier. Al2O3 supports were modified with Mg and Zn to produce Mg-Al2O3 and Zn-Al2O3 with a target loading of 3.8 wt.% for dopants. The modified supports were impregnated with chloroplatinic acid solution to produce the catalysts Pt/Al2O3, Pt/Mg-Al2O3 and Pt/Zn-Al2O3 of 0.5 wt.% Pt loading. Thereafter, the catalysts were characterised using inductively coupled plasma- optical emission spectrometry, scanning electron microscopy-energy dispersive X-ray spectroscopy, hydrogen temperature-programmed reduction, carbon-monoxide pulse chemisorption, ammonia temperature-programmed desorption, X-ray diffraction and transmission electron microscopy. The dehydrogenation experiments were performed using a horizontal plug flow reactor system and the catalyst time-on-stream was 22 h. Pt/Mg-Al2O3 showed the highest average hydrogen flowrate of 29 nL/h, while an average of 27 nL/h was obtained for both Pt/Al2O3 and Pt/Zn-Al2O3. This has resulted in a hydrogen yield of 80% for Pt/Mg-Al2O3, 71% for Pt/Zn-Al2O3 and 73% for Pt/Al2O3. In addition, the conversion of H18-DBT ranges from 99% to 92%, Pt 97–90% and 96–90% for Pt/Mg-Al2O3, Pt/Zn-Al2O3 and Pt/Al2O3, respectively. Following the latter catalyst order, the selectivity to dibenzyltoluene (H0-DBT) ranges from 78% to 57%, 75–51% and 71–45%. Therefore, Pt/Mg-Al2O3 showed improved catalytic performance towards dehydrogenation of H18-DBT.

Download Full-text