Editorial

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5 pages, 3651 KiB

Open AccessEditorial

Process Intensification in Chemical Reaction Engineering

by Vincenzo Russo, Stefan Haase and Pasi Tolvanen

Processes 2022, 10(7), 1294; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10071294 - 30 Jun 2022

Cited by 2 | Viewed by 1419

Abstract

Process Intensification (PI) is a modern trend in Chemical Reaction Engineering (CRE) science [...] Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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Research

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14 pages, 9779 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Reactive Chromatography Applied to Ethyl Levulinate Synthesis: A Proof of Concept

by Carmelina Rossano, Claudio Luigi Pizzo, Riccardo Tesser, Martino Di Serio and Vincenzo Russo

Processes 2021, 9(9), 1684; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9091684 - 20 Sep 2021

Cited by 4 | Viewed by 2297

Abstract

Levulinic acid (LA) has been highlighted as one of the most promising platform chemicals, providing a wide range of possible derivatizations to value-added chemicals as the ethyl levulinate obtained through an acid catalyzed esterification reaction with ethanol that has found application in the [...] Read more.

Levulinic acid (LA) has been highlighted as one of the most promising platform chemicals, providing a wide range of possible derivatizations to value-added chemicals as the ethyl levulinate obtained through an acid catalyzed esterification reaction with ethanol that has found application in the bio-fuel market. Being a reversible reaction, the main drawback is the production of water that does not allow full conversion of levulinic acid. The aim of this work was to prove that the chromatographic reactor technology, in which the solid material of the packed bed acts both as stationary phase and catalyst, is surely a valid option to overcome such an issue by overcoming the thermodynamic equilibrium. The experiments were conducted in a fixed-bed chromatographic reactor, packed with Dowex 50WX-8 as ion exchange resin. Different operational conditions were varied (e.g., temperature and flow rate), pulsing levulinic acid to the ethanol stream, to investigate the main effects on the final conversion and separation efficiency of the system. The effects were described qualitatively, demonstrating that working at sufficiently low flow rates, LA was completely converted, while at moderate flow rates, only a partial conversion was achieved. The system worked properly even at room temperature (303 K), where LA was completely converted, an encouraging result as esterification reactions are normally performed at higher temperatures. Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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39 pages, 13722 KiB

Open AccessFeature PaperArticle

Reactor Selection for Upgrading Hemicelluloses: Conventional and Miniaturised Reactors for Hydrogenations

by Stefan Haase, Cesar A. de Araujo Filho, Johan Wärnå, Dmitry Yu. Murzin and Tapio Salmi

Processes 2021, 9(9), 1558; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9091558 - 31 Aug 2021

Cited by 1 | Viewed by 2421

Abstract

This work presents an advanced reactor selection strategy that combines elements of a knowledge-based expert system to reduce the number of feasible reactor configurations with elaborated and automatised process simulations to identify reactor performance parameters. Special focus was given to identify optimal catalyst [...] Read more.

This work presents an advanced reactor selection strategy that combines elements of a knowledge-based expert system to reduce the number of feasible reactor configurations with elaborated and automatised process simulations to identify reactor performance parameters. Special focus was given to identify optimal catalyst loadings and favourable conditions for each configuration to enable a fair comparison. The workflow was exemplarily illustrated for the Ru/C-catalysed hydrogenation of arabinose and galactose to the corresponding sugar alcohols. The simulations were performed by using pseudo-2D reactor models implemented in Aspen Custom Modeler^® and automatised by using the MS-Excel interface and VBA. The minichannel packings, namely wall-coated minichannel reactor (MCWR), minichannel reactor packed with catalytic particles (MCPR), and minichannel reactor packed with a catalytic open-celled foam (MCFR), outperform the conventional and miniaturised trickle-bed reactors (TBR and MTBR) in terms of space-time yield and catalyst use. However, longer reactor lengths are required to achieve 99% conversion of the sugars in MCWR and MCPR. Considering further technical challenges such as liquid distribution, packing the reactor, as well as the robustness and manufacture of catalysts in a biorefinery environment, miniaturised trickle beds are the most favourable design for a production scenario of

5000 t / a

galactitol. However, the minichannel configurations will be more advantageous for reaction systems involving consecutive and parallel reactions and highly exothermic systems. Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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24 pages, 30036 KiB

Open AccessArticle

CO Preferential Oxidation in a Microchannel Reactor Using a Ru-Cs/Al₂O₃ Catalyst: Experimentation and CFD Modelling

by Kyatsinge Cedric Musavuli, Nicolaas Engelbrecht, Raymond Cecil Everson, Gerrit Lodewicus Grobler and Dmitri Bessarabov

Processes 2021, 9(5), 867; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9050867 - 14 May 2021

Cited by 3 | Viewed by 2338

Abstract

This work presents an experimental and modelling evaluation of the preferential oxidation of CO (CO PROX) from a H₂-rich gas stream typically produced from fossil fuels and ultimately intended for hydrogen fuel cell applications. A microchannel reactor containing a washcoated 8.5 [...] Read more.

This work presents an experimental and modelling evaluation of the preferential oxidation of CO (CO PROX) from a H₂-rich gas stream typically produced from fossil fuels and ultimately intended for hydrogen fuel cell applications. A microchannel reactor containing a washcoated 8.5 wt.% Ru/Al₂O₃ catalyst was used to preferentially oxidise CO to form CO₂ in a gas stream containing (by vol.%): 1.4% CO, 10% CO₂, 18% N₂, 68.6% H₂, and 2% added O₂. CO concentrations in the product gas were as low as 42 ppm (99.7% CO conversion) at reaction temperatures in the range 120–140 °C and space velocities in the range 65.2–97.8 NL g_cat⁻¹ h⁻¹. For these conditions, less than 4% of the H₂ feed was consumed via its oxidation and reverse water-gas shift. Furthermore, a computational fluid dynamic (CFD) model describing the microchannel reactor for CO PROX was developed. With kinetic parameter estimation and goodness of fit calculations, it was determined that the model described the reactor with a confidence interval far greater than 95%. In the temperature range 100–200 °C, the model yielded CO PROX reaction rate profiles, with associated mass transport properties, within the axial dimension of the microchannels––not quantifiable during the experimental investigation. This work demonstrates that microchannel reactor technology, supporting an active catalyst for CO PROX, is well suited for CO abatement in a H₂-rich gas stream at moderate reaction temperatures and high space velocities. Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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20 pages, 4095 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Influence of Macroscopic Wall Structures on the Fluid Flow and Heat Transfer in Fixed Bed Reactors with Small Tube to Particle Diameter Ratio

by Thomas Eppinger, Nico Jurtz and Matthias Kraume

Processes 2021, 9(4), 689; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9040689 - 14 Apr 2021

Cited by 6 | Viewed by 2364

Abstract

Fixed bed reactors are widely used in the chemical, nuclear and process industry. Due to the solid particle arrangement and its resulting non-homogeneous radial void fraction distribution, the heat transfer of this reactor type is inhibited, especially for fixed bed reactors with a [...] Read more.

Fixed bed reactors are widely used in the chemical, nuclear and process industry. Due to the solid particle arrangement and its resulting non-homogeneous radial void fraction distribution, the heat transfer of this reactor type is inhibited, especially for fixed bed reactors with a small tube to particle diameter ratio. This work shows that, based on three-dimensional particle-resolved discrete element method (DEM) computational fluid dynamics (CFD) simulations, it is possible to reduce the maldistribution of mono-dispersed spherical particles near the reactor wall by the use of macroscopic wall structures. As a result, the lateral convection is significantly increased leading to a better radial heat transfer. This is investigated for different macroscopic wall structures, different air flow rates (Reynolds number Re = 16 ...16,000) and a variation of tube to particle diameter ratios (2.8, 4.8, 6.8, 8.8). An increase of the radial velocity of up to 40%, a reduction of the thermal entry length of 66% and an overall heat transfer increase of up to 120% are found. Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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17 pages, 4321 KiB

Open AccessFeature PaperArticle

Shear-Thinning Effect of the Spinning Disc Mixer on Starch Nanoparticle Precipitation

by Sahr Sana, Vladimir Zivkovic and Kamelia Boodhoo

Processes 2020, 8(12), 1622; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8121622 - 09 Dec 2020

Cited by 4 | Viewed by 2459

Abstract

Spinning disc technology is capable of achieving intensified micromixing within thin liquid films created through large shear rates, typically of the order of 10³ s⁻¹, generated by means of fast disc surface rotation. In this study the effect of the [...] Read more.

Spinning disc technology is capable of achieving intensified micromixing within thin liquid films created through large shear rates, typically of the order of 10³ s⁻¹, generated by means of fast disc surface rotation. In this study the effect of the high shear on solvent–antisolvent mixing and starch nanoparticle precipitation is reported. Rheological studies of starch solutions at 2% w/v and 4% w/v have demonstrated their shear-thinning behaviour at the large shear rates experienced on the spinning disc surface. The effect of such high shear rate on starch nanoparticle precipitation is investigated alongside solute concentration and several other operating parameters such as flow rate, disc rotational speed, and solvent/antisolvent ratio. A reduction in nanoparticle size has been observed with an increase in starch concentration, although agglomeration was found to be more prevalent amongst these smaller particles particularly at larger flow rates and disc rotational speeds. Micromixing time, estimated on the basis of an engulfment mechanism, has been correlated against shear rate. With fast micromixing of the order of 1 ms observed at higher shear rates, and which are practically unaffected by the starch concentrations used, micromixing is not thought to be influential in determining the particle characteristics highlighted in this work. Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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32 pages, 1604 KiB

Open AccessArticle

Multi-Aspect Comparison of Ethyl Acetate Production Pathways: Reactive Distillation Process Integration and Intensification via Mechanical and Chemical Approach

by Branislav Šulgan, Juraj Labovský and Zuzana Labovská

Processes 2020, 8(12), 1618; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8121618 - 08 Dec 2020

Cited by 20 | Viewed by 6595

Abstract

This paper provides a multi-aspect comparison of selected methods of ethyl acetate production and shows the possibility of further reactive distillation process integration and sophisticated intensification including process stream regeneration. The production pathways were selected with respect to their practical applicability and sufficient [...] Read more.

This paper provides a multi-aspect comparison of selected methods of ethyl acetate production and shows the possibility of further reactive distillation process integration and sophisticated intensification including process stream regeneration. The production pathways were selected with respect to their practical applicability and sufficient experimental and feasibility studies already published. A total of four case studies were designed and compared: conventional process set-up (ethyl acetate is produced in a chemical reactor) is designed as a base case study; reactive distillation with a separation unit is derived from the conventional process set-up. The mechanical and chemical approach to reactive distillation process intensification and integration were assumed: reactive distillation column with a stripper and reactive distillation column with an auxiliary chemical reaction (ethylene oxide hydration). Process models were compiled in the Aspen Plus software. Complex process flowsheets of selected case studies including separation and regeneration were designed and optimized. Three different points of view were applied to evaluate the selected process benefits and drawbacks. Process energy, economy, and safety were assessed. As a result, a reactive distillation column with an auxiliary chemical reaction has been proven to be the most suitable pathway for ethyl acetate production assuming all three evaluated aspects. Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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24 pages, 7776 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Enhancing the Thermal Performance of Slender Packed Beds through Internal Heat Fins

by Nico Jurtz, Steffen Flaischlen, Sören C. Scherf, Matthias Kraume and Gregor D. Wehinger

Processes 2020, 8(12), 1528; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8121528 - 24 Nov 2020

Cited by 14 | Viewed by 2947

Abstract

Slender packed beds are widely used in the chemical and process industry for heterogeneous catalytic reactions in tube-bundle reactors. Under safety and reaction engineering aspects, good radial heat transfer is of outstanding importance. However, because of local wall effects, the radial heat transport [...] Read more.

Slender packed beds are widely used in the chemical and process industry for heterogeneous catalytic reactions in tube-bundle reactors. Under safety and reaction engineering aspects, good radial heat transfer is of outstanding importance. However, because of local wall effects, the radial heat transport in the vicinity of the reactor wall is hindered. Particle-resolved computational fluid dynamics (CFD) is used to investigate the impact of internal heat fins on the near wall radial heat transport in slender packed beds filled with spherical particles. The simulation results are validated against experimental measurements in terms of particle count and pressure drop. The simulation results show that internal heat fins increase the conductive portion of the radial heat transport close to the reactor wall, leading to an overall increased thermal performance of the system. In a wide flow range (

100 < R e_{p} < 1000

), an increase of up to 35% in wall heat transfer coefficient and almost 90% in effective radial thermal conductivity is observed, respectively. Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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17 pages, 5990 KiB

Open AccessFeature PaperArticle

Auto-Aspirated DAF Sparger Study on Flow Hydrodynamics, Bubble Generation and Aeration Efficiency

by Dmitry Vladimirovich Gradov, Andrey Saren, Janne Kauppi, Kari Ullakko and Tuomas Koiranen

Processes 2020, 8(11), 1498; https://0-doi-org.brum.beds.ac.uk/10.3390/pr8111498 - 19 Nov 2020

Cited by 2 | Viewed by 3092

Abstract

A novel auto-aspirated sparger is examined experimentally in a closed-loop reactor (CLR) at lab scale using particle image velocimetry, high-speed camera and oxygen mass transfer rate measurements. State-of-the-art 3D printing technology was utilized to develop the sparger design in stainless steel. An insignificant [...] Read more.

A novel auto-aspirated sparger is examined experimentally in a closed-loop reactor (CLR) at lab scale using particle image velocimetry, high-speed camera and oxygen mass transfer rate measurements. State-of-the-art 3D printing technology was utilized to develop the sparger design in stainless steel. An insignificant change in the bubble size distribution was observed along the aerated flow, proving the existence of a low coalescence rate in the constraint domain of the CLR pipeline. The studied sparger created macrobubbles evenly dispersed in space. In pure water, the produced bubble size distribution from 190 to 2500 μm is controlled by liquid flow rate. The bubble size dynamics exhibited a power-law function of water flow rate approaching a stable minimum bubble size, which was attributed to the ratio of the fast-growing energy of the bubble surface tension over the kinetic energy of the stream. Potentially, the stream energy can efficiently disperse higher gas flow rates. The oxygen transfer rate was rapid and depended on the water flow rate. The aeration efficiency below 0.4 kW/m³ was superior to the commonly used aerating apparatuses tested at lab scale. The efficient gas dissolution technology has potential in water treatment and carbon capture processes applications. Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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Review

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23 pages, 2796 KiB

Open AccessFeature PaperReview

Process Intensification in Chemical Reaction Engineering

by Stefan Haase, Pasi Tolvanen and Vincenzo Russo

Processes 2022, 10(1), 99; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10010099 - 04 Jan 2022

Cited by 17 | Viewed by 6113

Abstract

In the present review article, the definitions and the most advanced findings within Process Intensification are collected and discussed. The intention is to give the readers the basic concepts, fixing the syllabus, as well as some relevant application examples of a discipline that [...] Read more.

In the present review article, the definitions and the most advanced findings within Process Intensification are collected and discussed. The intention is to give the readers the basic concepts, fixing the syllabus, as well as some relevant application examples of a discipline that is well-established and considered a hot topic in the chemical reaction engineering field at present. Full article

(This article belongs to the Special Issue Process Intensification in Chemical Reaction Engineering)

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