15:30
Unconventional catalyst synthesis and manufacturing methods 5
Chair: Alexander Navarrete Muñoz
15:30
40 mins
#86
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KEYNOTE: Spatially structured catalysts and reactors for the transformation of CO2 to useful chemicals
Prof. Jorge Gascon
(presenter: Jorge Gascon)
Abstract: The increasing global CO2 levels has led to a massive thrust in research on both Carbon Capture and Storage (CCS) and Carbon Capture and Utilization (CCU). It has been posited that, in terms of volume, the contribution of CCU will be significantly less as compared to CCS for avoiding CO2 emissions and achieving the “2 degree scenario” (2DS) goals. However, what cannot be denied is that the immediate economic potential of CCU far outweighs that of CCS especially considering the fact that large scale capital investment is required in case of the latter.
While it is clear that CCS does need to be implemented in order to realistically achieve the 2DS goals, what is not commonly considered is that instead of approaching CCS and CCU as two separate methods of carbon mitigation, we should think of how CCU can, in fact, help address the problems faced for the implementation of CCS. With research intensifying on CCU, it is not impractical to think of an economic cycle where the profits gained from CCU can help to offset the costs of CCS if an integrated system of CCSU (Carbon Capture Storage and Utilization) is implemented. The reuse of stored CO2 can become beneficial if consumption of fossil fuels is greatly reduced over the next century and the stored CO2 becomes the chief feedstock for carbon-based chemicals.
Utilization of multi-functional catalysis is fast becoming the method of choice to boost the production of valuable chemicals from CO2. In this presentation, we will present several routes based on careful choice of catalytic components and reactor configuration to increase selectivity and productivity in the direct hydrogenation of CO2 to light olefins, aromatics and liquid fuels.
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16:10
20 mins
#44
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MICROREACTOR TECHNOLOGY IN THE INTENSIFIED PRODUCTION OF CHEMICAL INTERMEDIATES: SYNTHESIS OF CHLOROALKANES
Tapio Salmi, Sabrina Schmidt, Kari Eränen, Johan Wärnå, Nicola Gemo, Narendra Kumar, Dmitry Murzin
(presenter: Tapio Salmi)
Abstract:
Many products which are non-toxic and bio-degradable – green products – are made in processes, which have inevitable ‘non-green’ elements. Typical examples are cellulose derivatives, which have a huge number of world-wide applications. Typical cellulose derivatives are alkylcelluloses,which are made from cellulose and a chloroalkane. Flammable and toxic chloroalkanes are prepared via gas-phase hydrochlorination of the corresponding alcohol (R= CH3 or R=CH3CH2), ROH + HCl = RCl + H2O.
A heterogeneous catalyst, typically γ-Al2O3 is needed. Conventional industrial processes are based on fixed bed technology, but a safe and efficient way to carry out the reaction is to shift to microreactors, which even enable on-site production of chloroalkanes: produce, where you use, then the risks of transport and handling of chemicals is minimized.
The experimental work was carried out in stainless-steel microreactors (IMM Mainz) The microreactor consisted of mixing and catalytic zones, each equipped with ten stainless steel microstructured platelets. The catalyst platelets had nine straight channels each, 90-100 μm deep, 460 μm in diameter and 9.5 mm long. The platelets were coated with a neat γ-alumina catalyst using a slurry coating method prior to use. The thickness of the catalyst layer in the microchannels was 15 ± 3 μm. The alcohols and the organic reaction products were analyzed by gas chromatography.
An extensive series of experiments was conducted for both chloromethane and chloroethane. Detailed kinetic modelling of the hydrochlorination process was performed. The rate of hydrochlorination was described by a Langmuir-Hinshelwood model, in which HCl was presumed to be the most abundant surface intermediate and the surface reaction between the adsorbed alcohol and HCl was assumed to be rate determining. The fit of the kinetic model was excellent. The experiments with microreactors revealed that the process can be dramatically enhanced by introducting microreactor technology instead of conventional fixed bed technology. The reason is the thin catalyst layer thickness. In conventional reactors, the minimum catalyst particle size is limited by the pressure drop, and it is therefore difficult to use particles smaller than 1 mm. For rapid reactions, the diffusion resistance inside the pores of the catalyst layer becomes prominent even for relative thin layers. Numerical simulations of the reaction-diffusion model confirmed that the effectiveness factor for chloromethane synthesis was about 0.95, whereas it was 0.06-0.1 only for catalyst layers of 1-2 mm thickness, which implies that by using microreactors, a 10-fold reduction of the reactor size is easily obtainable.
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16:30
20 mins
#16
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A MILLION-MICROCHANNEL MULTIFUEL STEAM REFORMER FOR HYDROGEN PRODUCTION
Núria J. Divins, Jordi Llorca
(presenter: Núria J Divins)
Abstract: Different catalytic reforming technologies can be applied to generate hydrogen from different fuels, For on-site, on-demand applications reactor design is of paramount importance and the use of integrated microreaction technologies is a must. Herein, we show the use of catalytic Si micromonoliths containing ca. 5 million microchannels of only 3.3 µm in diameter coated with a robust RhPd/CeO2 catalyst for the steam reforming of ethanol, acetic acid, acetone, methoxythanol, isopropanol and diesel. Lowering the dimensions of the microchannels has a strong effect on the geometric surface area exposed to reactants, which in turn has a dramatic effect on the yield of hydrogen obtained calculated on a volumetric basis.
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16:50
20 mins
#21
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THE IMPORTANCE OF CATALYST COATING ARCHITECTURE IN THE DIRECT SYNTHESIS OF DME WITH STRUCTURED CATALYSTS
Iñigo Pérez-Miqueo, Oihane Sanz, Mario Montes
(presenter: Oihane Sanz)
Abstract: Metallic structured reactors offer high surface/volume ratio, which allows increasing volumetric productivity, while reducing pressure drop and improved heat transfer. The direct synthesis of dimethyl ether (a clean alternative to diesel fuel) is highly exothermic reactions but represents a simpler and more economical process than the traditional two steps method due to the use of one single reactor and the removal of thermodynamic limitations of methanol synthesis [1]. The use of structured catalysts allows excellent temperature control (a key point of this process), good catalyst stability and higher volumetric productivity than the conventional two reactors technology. However, structuring the catalyst for this reaction involves contacting two different active phases, which can generate undesired interactions if the catalysts do not present the proper contact between them (Figure 1).
In this work, different catalyst architectures have been studied preparing washcoated metallic monoliths and powder fixed beds. The different systems have been characterized and compared with special emphasis on the thermal conductivity and the volumetric productivity of DME (process intensification).
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