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Catalytic combustion of hydrogen and ammonia containing off-gas surrogate from an ammonia solid oxide fuel cell (SOFC) was studied with a focus on nitrogen oxides (NOx) mitigation. Noble and transition metals (Pt, Pd, Ir, Ru, Rh, Cu, Fe, Ni) supported on Al2O3 were tested in the range of 100 to 800 °C. The tested catalysts were able to completely convert hydrogen and ammonia present in the off-gas. The selectivity to NOx increased with reaction temperature and stagnated at temperatures of 600 °C and higher. At low temperatures, the formation of N2O was evident, which declined with increasing temperature until no N2O was observed at temperatures exceeding 400 °C. Over nickel and iridium-based catalysts, the NOx formation was reduced drastically, especially at 300 to 400 °C. To the best knowledge of the authors, the current paper is the first study about catalytic combustion of hydrogen-ammonia mixtures as a surrogate of an ammonia-fed SOFC off-gas.

The current paper reports from development of an auxiliary power unit primarily dedicated for aviation purposes as additional energy source for different possible supply scenarios for passenger aircrafts not discussed in detail here. Three microstructured plate heat-exchanger reactors were switched in series, coated with appropriate self-developed catalysts utilising propylene glycol as fuel. They were designed to feed a fuel cell with a net power output of 5 kW. These reactors are an oxidative steam reformer coupled with a catalytic burner for propylene glycol, an air-cooled water-gas shift reactor and a preferential oxidation reactor with integrated evaporation cooling. Along with a monolithic start-up burner, a heat-exchanger and a hot gas driven evaporator they were forming the components of a highly integrated fuel processor system. To the knowledge of the authors, the described system is the first fuel processor developed for polyalcohol fuel of that size. It had been presented first in the scope of a keynote lecture, however, without any details about reactor performance [ 1 ].

A two-dimensional model was developed for H2S chemisorption in different S-trap designs, including (i) ZnO coated monolith channels, (ii) ZnO fixed bed, and (iii) a new design. The new design was based on a modification of the monolithic reactor with adsorbent (ZnO) particles for filling the microchannels. The predicted concentration breakthrough curves were consistent with experimental literature data dealing with fixed bed and monolith S-traps.

The effect of metal oxide (CeO2, Al2O3 and ZrO2) support and In2O3 co-supported Pt catalysts has been investigated on steam reforming of methanol in microreactors. CeO2, Al2O3 and ZrO2 were prepared by the sol-gel method and they were used as a support, which was impregnated with In2O3 as co-support followed by the introduction of Pt species via the wet impregnation method. The size and dispersion of the Pt nanoparticles on In2O3/support have been examined by transmission electron microscopy. From these TEM and XPS results, it was found that the addition of In2O3 supports the formation of a high concentration of metallic Pt nanoparticles with enhanced dispersion and controlled particle size on the surface. The activity and stability of all the developed catalysts were tested for the steam reforming of methanol in microreactors at different temperatures. Under reforming conditions without prior reduction, a Pt/CeO2 catalyst containing 15 wt % of Pt exhibited complete methanol conversion and high selectivity towards hydrogen at 350 °C. However, the CO formation was found to be very high (7.0 vol %) for this catalyst. Upon addition of In2O3 as a co-support to this formulation the formation of CO decreased considerably. Pt/In2O3/CeO2 catalyst containing 15 wt % of Pt and 15 wt % of In2O3 showed excellent catalytic performance at much lower concentration of CO. This change could be closely associated with the formation of metallic Pt nanoparticles with smaller size, higher dispersion with strong interaction between Pt, In2O3 and support, which creates more oxygen vacancies to activate the water molecule which then react with methanol to produce H2 and CO2 suppressing the CO formation. Moreover, CeO2 supported Pt/In2O3 catalyst displayed higher stability with lowest CO formation under continuous steam reforming operation of 100 h. The superior performance of this catalyst is thought to be due to the relative abundance of redox sites on the CeO2 surface, which is able to create an oxygen vacancy as it possesses higher oxygen storage capacity and oxygen exchange capacity. This work demonstrates that the nature of support plays a crucial role for the continuous activation of reactants and determines the catalytic stability during methanol steam reforming.

The influence of process variables on the DME-to-hydrocarbon (DtH) conversion has been assessed. The reaction was studied at atmospheric pressure, over an MFI zeolite (H-ZSM-5, SiO2/Al2O3 = 58), in a gradientless recycle reactor, under the kinetic regime, and process variables in the range of 598-648 K and space time in the range of 0.008-0.040 h kgcat kgDME -1. The results showed that DME and methanol are not in equilibrium, that the cis-/trans-C4 olefins are in equilibrium with each other but not with the 1-butene, while C5 + hydrocarbons are favored at high oxygenates conversion. Finally, it was observed for the first time, to best of the knowledge of the current authors, that under kinetically controlled conditions, the selectivity to main groups of products can be described by the oxygenates conversion (xoxy), independently of the process conditions, which means that the xoxy controls the process selectivity independently of reaction temperature and space time.

Increasing source runtime, speeding up the transient response, while minimizing weight, volume and cost of the power supply system are key requirements for portable, mobile and off-grid applications of fuel cells. In this respect, Internal Reforming Methanol Fuel Cell (IRMFC) modules were designed, constructed and tested based on an innovative double reformer (DRef) configuration and metallic bipolar plates (BPPs) with unique arrangement. Recently developed cross-linked Advent TPS® high-temperature membrane electrode assemblies (MEAs) were employed for fuel cell operation at 210 °C. Taking into account the requirement for a light-weight and low-volume stack, Cu-based methanol reforming catalyst were supported on carbon papers, resulting in ultra-thin reformers. The proposed configuration offered a significant decrease in the weight and volume of the whole power system, as compared with previous voluminous foam-based modules. Moreover, specifically designed bipolar plates were made of coated Al-metal alloys, which proved to be stable in the strong acidic environment at elevated temperatures. The prototype 32MEAs-32DRef IRMFC stack of 100 W including home-made insulation casing, was integrated for operation at 200–210 °C and at 0.2 A cm−2, demonstrating the functionality of the unit. A power output of 100.7 W (3.14 W per cell; 0.114 W cm−2) was achieved in the last run following several on-off cycles. The volumetric power density of the IRMFC stack including insulation and casing is around 30 W per lt, being among the highest reported either in the case of portable or stationary applications. Overall, the observed stability of reformers and bipolar plates was satisfactory within the timeframe of the work undertaken. Specific targets for improvement of the efficiency were identified, and the main drawback had to do with low thermal and mechanical stability of the membranes under start-up/shut-down transient operation.

A tanks-in-series model has been developed for modeling the transfer processes in a high-temperature proton exchange membrane electrochemical hydrogen pump (HT-EHP). The model is based on the mass and charge balance equations. The predicted HT-EHP performance is consistent with experimental literature data.

Carbon dioxide methanation was carried out over Ni-based catalysts on different supports and chelating ligands in microreactors. To investigate the influence of chelating ligands and supports, the Ni catalysts were prepared using different support such as CeO2, Al2O3, SiO2, and SBA-15 by a citric acid (CA)-assisted impregnation method. The properties of the developed catalysts were studied by X-ray diffraction (XRD), Transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS) measurement, and the results show that the addition of CA in the impregnation solution improved the dispersion, refines the particle size, and enhanced the interaction of nickel species. The catalytic performance of the developed Ni catalysts were evaluated by CO2 methanation in microreactors in the temperature range of 275 °C–375 °C under 12.5 bar pressure. All the catalysts exhibit high CO2 conversion and extremely high selectivity to methane. However, the catalysts prepared via CA-assisted method exhibited excellent activity and stability, compared with Ni catalysts prepared by a conventional impregnation method, which could be attributed to highly dispersed nickel particles with strong metal–support interaction. The activity of CO2 methanation followed the order of Ni/CeO2-CA > Ni/SBA-15-CA > Ni/Al2O3-CA > Ni/SiO2-CA > Ni/CeO2. The Ni/CeO2 catalysts have also been prepared using different chelating ligands such as ethylene glycol (EG), sucrose (S), oxalic acid (OA) and ethylene diamine tetra acidic acid (EDTA). Among the tested catalysts prepared with different support and chelating ligands, the Ni/CeO2 catalyst prepared via CA-assisted method gave superior catalytic performance and it could attain 98.6% of CO2 conversion and 99.7% methane selectivity at 325 °C. The partial reduction of the CeO2 support generates more surface oxygen vacancies and results in a high CO2 conversion and methane selectivity compared with other catalysts. The addition of CA as promoter favored the synergistic effect of Ni and support, which led to high dispersion, controls the size, and stabilizes the Ni nanoparticles. Furthermore, the Ni/CeO2-CA catalyst yields high CO2 conversion in a time-on-stream study due to the ability of preventing the carbon deposition and sintering of Ni particles under the applied reaction conditions. However, the Ni/Al2O3-CA and Ni/SBA-15-CA catalysts showed stable performance for 100 h of time on stream.

In this work, several kinetic models have been studied for the methanol dehydration to dimethyl ether (DME), applying a commercial ZSM-5 catalyst rather than state-of-the-art alumina. The kinetic tests were carried out in a fixed-bed external-recycle reactor, in the absence of temperature and concentration gradients. Kinetic parameters of the different models were calculated and evaluated against physicochemical constraints and guidelines on entropy values. After discrimination, it was concluded that a modification of a model previously developed by Klusácek & Schneider for methanol dehydration over different catalyst formulations than alumina or zeolites describes best the methanol dehydration reaction, with excellent agreement between experimental data and calculated values. The selection of this model supports a mechanism in which methanol experiences dissociative adsorption and a surface reaction is the rate determining step (RDS) of the catalytic cycle. The kinetic measurements were performed at a total pressure of 1 bar, partial pressure of methanol (pm) from 0.3 bar to 1 bar, temperatures from 140 °C to 190 °C, weight hourly space velocities (WHSV) from 15 h−1 to 100 h−1, and two different amounts of water content (0 and 30 wt%). Experiments at different methanol concentrations in the feed revealed a weak dependence of the rate on pm. It could be determined to our knowledge for the first time that the reaction order with respect to water is negative, in the range of −0.80 to 0, thus providing quantitative proof of the inhibition effect of water on the methanol dehydration reaction rate over ZSM-5 catalysts, while DME showed no effect.

The influence of morphology and crystalline facets of nanoshaped ceria oxide support in Rh/CeO 2 and Rh/CeO 2/Al 2O 3 catalysts have been investigated by oxidative steam reforming of propylene glycol in microreactors at 630 °C at S/C = 3.5 and O/C = 0.15. First, well−defined ceria nanorods (NRs) and nanocubes (NCs) have been successfully synthesized by a facile hydrothermal method and then they are deposited on to α−Al 2O 3. The result of transmission electron microscopy indicates that the ceria nanorods exposed (110) and (100) planes but nanocubes possess only (100) planes. The developed shape controlled ceria nanocrystals and they are mixed with alumina have been used as supports for the preparation of highly dispersed and size controlled Rh nanoparticles of Rh/CeO 2 and Rh/CeO 2/Al 2O 3 catalysts. Their performance was tested for the propylene glycol reforming reaction in microreactors, which provide high surface of the catalyst coatings, heat and mass transfer rate and controllability. The XPS and TEM results indicate that the CeO 2 morphology shows the selective exposure of different crystal planes which has a significant impact on the dispersion of Rh nanoparticles that influenced in the reforming reaction. The steam reforming reaction experiments show that the ceria nanorods supported Rh catalyst was achieved significantly better activity and stability for 100 h of time on stream than for the all other catalysts. This could be related to the better dispersion of Rh species and the higher surface oxygen vacancies associated with the exposed (100) and (110) crystal planes favor the stabilization of Rh nanoparticles against sintering and elimination of carbon deposition on active Rh nanoparticles during reforming reaction.

The modeling of transfer processes is a step in the generalization and interpretation of experimental data on heat transfer. The developed two-dimensional model is based on a homogeneous mixture model for boiling water flow in a microchannel with a new evaporation submodel. The outcome of the simulation is the distribution of velocity, void fraction and temperature profiles in the microchannel. The predicted temperature profile is consistent with the experimental literature data.

Highly dispersed and size controlled Ni nanoparticles in CeO2, ZrO2 and CeO2-ZrO2 promoted mesoporous SBA-15 silica were achieved with the aid of treatment by ultrasound. The catalysts were characterized systematically to investigate their morphological structure and surface properties. It was found that Ni nanoparticles with an average particle size of about 4.5 nm have been successfully embedded in the nanochannels of SBA-15 with a homogeneous distribution. The incorporated CeO2 and ZrO2 promotors effectively controlled the size of the Ni particles via strong Ni-promotor interaction, leading to well dispersed Ni particles in the confined nanochannels of SBA-15. The catalysts thus obtained were applied for steam reforming of propylene glycol in continuous flow microchannel reactors, which reduce the heat and mass transfer limitations when operating them under conditions of highly endothermic reforming reactions. The CeO2, ZrO2 and CeO2-ZrO2 promoted Ni/SBA-15 catalysts exhibited superior activity and enhanced long-term stability compared to the Ni/SBA-15 catalyst without promotor addition. This can be attributed to the strong interaction between Ni and the promotors and the confinement effect of the SBA-15 support restricted the sintering of Ni particles. The surface oxygen species arising from CeO2 and ZrO2 contributed to suppressing the carbon deposition effectively, leading to a consistent catalytic performance during propylene glycol reforming.

The CO2 methanation reaction was studied over catalysts containing different amounts of nickel (10-40 wt.%), prepared by the impregnation of alumina, zirconia and ceria supports with aqueous solutions of nickel nitrate and citric acid. It was found that the nickel content did not have a strong influence on the porosity and specific surface area of the respective catalysts. The reducibility of the catalysts decreased in order Ni-CeO2 > Ni-ZrO2 > Ni-Al2O3. High activation temperature was required for alumina supported catalysts. The active surface area of alumina supported catalysts increased with an increase of nickel loading. In contrary, the decrease of the active surface area with an increase of nickel content was observed for zirconia supported catalysts. Hydrogen temperature-programmed desorption studies indicated that the nature of nickel surface sites was influenced by the metal-support interactions. An increase in reduction temperature of CeO2 supported catalysts led to a pronounced increase of mean nickel crystallite size and a decrease of the active surface area. Alumina supported catalysts revealed high resistance against sintering. The catalysts showed high activity and selectivity to methane at low reaction temperatures (200-300 °C). Gradual increase in CO2 conversion with an increase of Ni loading was observed for alumina supported catalysts. Such effect was less evident for ceria and zirconia supported catalysts. Ceria supported catalysts, in spite of lower active surface area showed higher activity than alumina supported catalysts. In-situ Diffuse Reflectance Fourier Transform Infrared spectroscopy studies underlined the influence of the support composition on the course of surface reactions in CO2 methanation.

Catalytic reduction of CO2 to methane has been recognized as one of the most important strategic reactions to produce highly valuable chemicals and for storage of renewable energy (power-to-gas). This study demonstrates a crystal facet-dependent catalytic reduction of CO2 to CH4 on ruthenium nanoparticles deposited over TiO2 nanocrystal with exposed (001) and (101) facets. Compared with TiO2 (101) nanocrystal with the same Ru loading, Ru nanoparticles supported by TiO2 (001) exhibited a highly enhanced CO2 conversion rate and significantly improved methanation reactivity, along with a considerable durability. The physicochemical properties of the samples were characterized by HR-TEM, XRD, BET, FT-IR, UV-vis, Raman, ICP, and temperature-programmed reaction with CO2, and CO2 + H2. In view of the difference in catalytic activity and the physicochemical properties of the supported Ru/TiO2 catalysts, the results uncovered that the nature of the catalyst support of Ru/TiO2 strongly affected the dispersion of Ru species and the synergistic effect between Ru and underlying TiO2 supporting materials due to the strong metal-support interaction, and thus affected their capability to activate CO2 and determined the catalytic activity for CO2 methanation. Our work demonstrated the important role of the exposed crystal facets of the underlying support and the resulting Ru particle which had a large effect on CO2 methanation.

Pt/In2O3/Al2O3 catalysts with extremely low Pt loading (1.0 wt%) prepared by incipient-wetness impregnation method were evaluated for methanol steam reforming (MSR) in the temperature range of 200–500 °C, and characterized by means of X-ray diffractions (XRD), high resolution transmission electronic microscopy (HRTEM), Brunauer–Emmett–Teller (BET), CO chemisorption, hydrogen temperature-programmed reduction (H2-TPR) and H2O temperature-programmed desorption (H2O-TPD). Multiple factors including Pt/In2O3 mass ratio, total In2O3 loadings, steam to carbon ratio (S/C) and gas hourly space velocity (GHSV) were found to affect the catalytic properties. Results indicated that indium oxide was homogeneously dispersed on the surface of Al2O3 and also effectively improved the dispersion of Pt nanoparticles. Meanwhile, a good correlation of water activation ability with catalytic selectivity has been established. Accordingly, the synergistic effect caused by the strong Pt–In2O3 interaction and the intimate Pt–In2O3 contact played the crucial role in effective H2O activation, thus minimizing the CO selectivity and enhancing the stability of Pt/In2O3/Al2O3 catalysts because of its high ability to activate H2O molecule. As a result, the Pt/In2O3/Al2O3 catalyst with Pt/In2O3 mass ratio at 1/30 exhibited complete methanol conversion, 99.6% H2 selectivity and extremely low CO selectivity of 3.2% at 350 °C, outperforming Pt/ZnO/Al2O3 catalyst. Furthermore, Pt/In2O3/Al2O3 catalyst displayed higher stability than Pt/ZnO/Al2O3 catalyst as evidenced by unnoticeable deactivation under continuous operation for more than 16 h.

A kinetic study of methanol steam reforming over bimetallic Pt/In 2 O 3 /Al 2 O 3 catalyst was carried out. The kinetic measurements were performed in a microstructured monolithic reactor with an external recycle free of temperature and concentration gradients. By the help of residence time distribution measurements it could be verified that the reactor showed the behaviour of an ideal continuous stirred tank reactor (CSTR). The absence of external and internal concentration gradients could be proven by corresponding experiments and theoretical diagnostic criteria. The kinetic measurements performed by variation of the reactant inlet partial pressures revealed that in the temperature range from 310 °C to 355 °C the molar rate of methanol consumption mainly depends on the methanol partial pressure, especially at higher temperatures, whereas there is only minor dependence on the water partial pressure. Carbon dioxide has no inhibiting effect, whereas hydrogen showed a weak inhibiting effect. Two power laws and three Langmuir-Hinshelwood rate equations were created for the modelling of the kinetic data. Power laws could not be fitted to the measured values. Therefore the uses of Langmuir-Hinshelwood rate laws with temperature dependent sorption constants are inevitable for the modelling. The model discrimination revealed that the rate law derived from a mechanism, which assumes the dehydrogenation of an adsorbed methoxy-species as rate determining step, described the measured kinetic data second best. Optimum agreement between observed and predicted molar rates of methanol consumption was obtained when applying a Langmuir-Hinshelwood rate law assuming dissociative methanol and molecular water adsorption on the catalyst surface. Dissociative adsorption of water and methanol at the same active site may be excluded. This leads to a better evaluation of the models that assume molecular water adsorption at the same site where methanol ties or the ones with no participation of water in the rate determining step (RDS) under discrimination.

A small scale demonstration plant was designed, set up and operated for the heterogeneously catalysed synthesis of biodiesel under supercritical conditions. An ASPEN plus model was applied to minimise the energy demand for the product purification stages, which were identified as the point of highest energy consumption of the process owing to the high molar excess of methanol required for the process (40:1 molar excess, 1.45:1 on a mass basis). Vacuum distillation followed by a small rectification column was identified as the optimum solution. The determination of the energy demand of the plant revealed the economic viability of the process as far as the energy consumption is concerned. The plant could be operated at full conversion of the feed (not raffinated rapeseed oil). The catalyst incorporated into the plant had been selected out of a large number of possible formulations through a screening procedure applying tricaprin as model substance. γ-Al2O3 modified by acid treatment and La2O3 supported by γ-Al2O3 were identified as most promising candidates. The stability of these formulations was proven through long term stability tests. They revealed stable conversion for different feed stock such as raffinated rapeseed oil, not raffinated rapeseed oil and Used Cooking Oil (UCO), while for partially fermented rapeseed oil severe catalyst deactivation was observed after 250 h test duration.

In this paper a control system for autothermal reforming reactor for diesel fuel is presented. Autothermal reforming reactors and the pertaining purification reactors are used to convert diesel fuel into hydrogen-rich reformate gas, which is then converted into electricity by the fuel cell. The purpose of the presented control system is to control the hydrogen production rate and the temperature of the autothermal reforming reactor. The system is designed in such a way that the two control loops do not interact, which is required for stable operation of the fuel cell. The presented control system is a part of the complete control system of the diesel fuel cell auxiliary power unit (APU).

A proof-of-concept 70 W Internal Reforming Methanol Fuel Cell (IRMFC) stack including Balance-of-Plant (BoP) was designed, assembled and tested. Advent TPS® high-temperature, polymer electrolyte membrane electrode assemblies were employed for fuel cell operation at 200 °C. In order to avoid phosphoric acid poisoning of the reformer, the anode electrocatalyst of each cell was indirectly adjoined, via a separation plate, to a highly active CuMnAlOx catalyst coated onto copper foam, which served as methanol reforming layer. The reformer was in-situ converting the methanol/steam feed to the required hydrogen (internal reforming concept) at 200 °C, which was readily oxidized at the anode electrodes. The operation of the IRMFC was supported through a number of BoP components consisting of a start-up subsystem (air blower, evaporator and monolithic burner), a combined afterburner/evaporator device, methanol/water supply and data acquisition units (reactants/products analysis, temperature control, flow control, system load/output control). Depending on the composition of the liquid MeOH/H2O feed streams, current densities up to 0.18 A cm−2 and power output up to 70 W could be obtained with remarkable repeatability. Specific targets for improvement of the efficiency were identified.

The thermal coupling of endothermic and exothermic reactions is an important pathway for integrated thermal management within chemical reactors, which supports process intensification. Microchannel reactors are unique in the sense that they provide various design and operational characteristics that benefit high throughput and millisecond contact time chemical conversions. These include high microchannel aspect ratios, improved heat transfer (via thin and thermally conductive reactor substrates), and enhanced mass transfer (due to limited diffusional effects). In this review of experimental and simulated microchannel reactors, focus is put on improved designs and operating strategies to support thermal conduction across microchannel walls, yet keep chemical products from the respective reactions separate using spatially-segregated reaction chambers. Three common flow configurations (counter-current, co-current and cross-flow designs) are critically discussed as a result of their abilities to distribute ‒ and in some cases recirculate ‒ reaction heat, the steady-state temperature profiles established within them as a result of flow direction, and reactant conversions/product yields as a result of their thermal characteristics. Special attention is devoted to microchannel design aspects, including wall thermal conductivity, channel dimensions, catalyst positioning and other design strategies (distribution manifolds and heat recirculative reactor designs) to improve heat and mass flows within microchannel reactors.

Many critical issues need to be addressed when microstructured reactors are manufactured in large unit volumes. The most crucial of these are cost, ease of production, and reliability. The lack of breakthrough manufacturing technology to provide high-efficiency, low-cost, high-precision plates is a hindrance to the early market implementation of systems requiring metallic microstructured plates. This contribution focuses on the development and optimization of a combined embossing and bending tool for the quick and continuous manufacture of easily machined plates.

The environmental profile of plasma assisted methane reforming for the production of synthesis gas was researched. A miniaturized gliding arc discharge reactor was applied for the partial oxidation of methane in this study. The best operational condition regarding to the lowest CO2-eq emission was screened out. Studied were the global warming potential, the acidification potential, the eutrophication potential, the human toxicity, the NOx photochemical oxidant creation potential, and the ozone depletion potential. The electricity consumption was the main contribution to the four of these six impacts. A sensitivity research of different energy resources of electricity and electricity mix of different countries was carried out in order to decrease the emission caused by the electricity consumption. Then, the conventional steam reforming was benchmarked to the plasma reforming process, which shows that the global warming potential of the plasma reforming is comparably on the same level as the conventional reforming only in the case when the electricity is generated from renewable or clean energy. So, the environmental impact research of the plasma assisted methane reforming in lab scale shed light on its industrial application from the viewpoint of the environmental profile. In order to decrease the emissions from electricity production, it’s recommended that such plasma plant should be built close to power plants from the renewable or clean energy. The compactness of plasma plants due to their expected process intensification would facilitate such distributed approach, while conventional reforming plants are very large and need Verbund-type integration into ChemParks. Finally, another option to make the plasma reforming process more energy efficient and green is proposed which is to combine the plasma reforming unit with Solid Oxide Fuel Cells.

The current chapter provides a non-comprehensive overview about innovative design aspects for microstructured heat exchangers focussing on an enhancement of the heat transfer at minimum increase of the pressure drop. It turns out that smooth deviations of the flow from the original direction are required to achieve this goal while more severe interference of the flow as it is achieved through irregular structures such as foams leads to higher pressure drop penalties compared to the enhancement of the heat transfer when compared on a dimensionless basis. When designing such devices on the smaller scale, it is mandatory to take into account the effect of axial heat transfer which might deteriorate the heat exchanger performance considerably. Cheap fabrication techniques are required to allow the practical application of such devices, which then have a multitude of potential applications from process industry to aerospace.

Wash-coated Pt/CeO 2 , Pt/CeO 2 /ZrO 2 and Pt/Cu/CeO 2 and Pt/CeO 2 /Al 2 O 3 based formulations were tested in sandwich type microreactors for water–gas shift (WGS) activity. At low reaction temperature of 260 °C, low conversion of carbon monoxide was initially observed which increased considerably upon the addition of air, a behaviour which was observed even after multiple cycles of start-up, operation with and without air and shut-down. At a higher reaction temperature of 400 °C air addition did not further improve the performance of the catalysts, which converted the carbon monoxide already close to equilibrium. One of the catalysts was incorporated into a larger reactor of kW scale and tested for its performance under conditions of WGS and oxygen enhanced WGS. The carbon monoxide conversion was increased by the air addition also on the larger reactor.

In this work the validation of ethylene glycol (EG) as raw material for hydrogen production by steam reforming (SR) and oxidative steam reforming (OSR) reactions was studied using microchannel testing reactors. The experiments were carried out at a steam to carbon ratio (S/C) of 4.0, several temperatures and atmospheric pressure. Rh based catalysts were designed using α-Al2O3 modified with different contents of CeO2 or La2O3 oxides as their supports. Different temperatures were tested for SR experiments (725, 675 and 625 °C) at a volume hourly space velocity (VHSV) of 200 NL/h gcat as well as different VHSV (300 and 100 NL/h gcat) at a constant temperature of 675 °C. In the case of OSR experiments, only the effect of the VHSV was studied at 675 °C. A long term experiment was carried out with the 2.5Rh–20Ce catalyst which lasted over 115 h in stable conditions. The catalysts physicochemical properties were studied by their characterization using the following techniques: ICP-AES, N2 physisorption, TPR, TEM, XRD and XPS.

The current paper focuses on the miniaturization and utilization of the GlidArc® principle for the reforming of fuel gases (such as methane and propane) to synthesis gas (H2 + CO). The reforming characteristics and optimal operating conditions to achieve maximum synthesis gas yield were determined. Parametric screening studies were performed with different (i) atomic ratios of oxygen to carbon (O/C) in the range from 1 to 2, (ii) and feed flow rates from 2 to 10 L/min using alternating current voltage to produce the plasma in the reactor, which was varied from 2.8 to 4.6 kV. A Higher synthesis gas ratio of H2/CO ≈ 2.35 was achieved when methane was processed at O/C = 1 in comparison with propane (H2/CO ≈ 1.52).

The surface state of the Pt/In2O3/Al2O3 catalyst coated onto a microchannel stainless steel reactor was investigated under working conditions using synchrotron-based ambient pressure photoelectron (APPES) and X-ray absorption near-edge structure (XANES) spectroscopies, combined with online mass spectrometry. The surface of the fresh catalyst consists of metallic Pt, In2O3, and Al2O3. Reduction under 0.2 mbar of H2 at 250 °C leads to surface enhancement of Pt and partial reduction of In2O3, while Al2O3 remains unchanged. Reoxidation in O2 atmosphere stimulates surface segregation of In2O3 over Pt, accompanied by partial oxidation of Pt to PtOx. Based on these results a dynamic, gas-phase-dependent surface state is demonstrated. Under methanol steam reforming conditions, the surface state rapidly adapts under the reaction stream regardless of the pretreatment. However, correlation of gas phase with spectroscopic results under working conditions pointed out the beneficial effect of surface indium to reduce t...

In this work Pt based mono and bimetallic catalysts were deposited into microchannel testing reactors and tested under conditions of water-gas shift (WGS). All the catalysts contained 25% of CeO 2 and a metal loading of 2.5% or 5.0% (nominal wt.%). The bimetallic catalysts contained 2.5% Pt and 2.5% of Me where Me = Ni, Co, Mo, Pd, Fe, Re, Y, Cu or Zn. The feed gas composition amounted to 46.23% H 2 , 8.82% CO 2 , 7.94% CO and 37.02% H 2 O (vol.%). The tests were performed at reaction temperatures between 300 °C and 450 °C. 2.1Pt–2.1Re was identified as the catalyst formulation of highest activity. The composition and the preparation method of this catalyst were then modified for further activity and stability improvement. All the catalysts under investigation were characterized applying the following techniques: inductively coupled plasma atomic emission spectroscopy (ICP-AES), N 2 physisorption, temperature programmed reduction (TPR), CO chemisorption, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The activity of the benchmark 3.6Pt catalyst was improved by the 2.1Pt–2.1Re catalyst and the stability of this catalyst was further improved by increasing slightly the nominal Pt content up to 3.33%. Therefore, a significant reduction of the Pt content compared to the benchmark 3.6Pt catalyst was achieved through the incorporation of Re.

Two novel routes for the production of gasoline from pyrolysis oil (from timber pine) and biogas (from ley grass) are simulated, followed by a cradle-to-gate life-cycle assessment of the two production routes. The main aim of this work is to conduct a holistic evaluation of the proposed routes and benchmark them against the conventional route of producing gasoline from natural gas. A previously commercialized method of synthesizing gasoline involves conversion of natural gas to syngas, which is further converted to methanol, and then as a last step, the methanol is converted to gasoline. In the new proposed routes, the syngas production step is different; syngas is produced from a mixture of pyrolysis oil and biogas in the following two ways: (i) autothermal reforming of pyrolysis oil and biogas, in which there are two reactions in one reactor (ATR) and (ii) steam reforming of pyrolysis oil and catalytic partial oxidation of biogas, in which there are separated but thermally coupled reactions and reactors (CR). The other two steps to produce methanol from syngas, and gasoline from methanol, remain the same. The purpose of this simulation is to have an ex-ante comparison of the performance of the new routes against a reference, in terms of energy and sustainability. Thus, at this stage of simulations, nonrigorous, equilibrium-based models have been used for reactors, which will give the best case conversions for each step. For the conventional production route, conversion and yield data available in the literature have been used, wherever available.The results of the process design showed that the second method (separate, but thermally coupled reforming) has a carbon efficiency of 0.53, compared to the conventional route (0.48), as well as the first route (0.40). The life-cycle assessment results revealed that the newly proposed processes have a clear advantage over the conventional process in some categories, particularly the global warming potential and primary energy demand; but there are also some in which the conventional route fares better, such as the human toxicity potential and the categories related to land-use change such as biotic production potential and the groundwater resistance indicator. The results confirmed that even though using biomass such as timber pine as raw material does result in reduced greenhouse gas emissions, the activities associated with biomass, such as cultivation and harvesting, contribute to the environmental footprint, particularly the land use change categories. This gives an impetus to investigate the potential of agricultural, forest, or even food waste, which would be likely to have a substantially lower impact on the environment. Moreover, it could be seen that the source of electricity used in the process has a major impact on the environmental performance.

Zur Industrie 4.0 gehören prozessanalytische Methoden, die schnellstmöglich chemische Informationen über Edukte, Zwischenstufen und Produkte liefern. Erforderlich für Prozessführung und Bilanzierung sind automatische, reproduzierbare und repräsentative Probennahme und Online-Totalanalyse aller Komponenten. In der Kraftstoffsynthese funktioniert dies auch mit einem speziell konfigurierten Gaschromatographen mit massenselektivem Detektor.

A methanol reformer was designed, built and tested, which allows hydrogen production for high temperature PEM fuel cells for mobile applications applying micro-structured plate heat-exchanger technology and a novel, highly active catalyst formulation for oxidative steam reforming of methanol at temperatures exceeding 300 °C. It is one of the first micro-structured methanol reformers with integrated anode off-gas combustion, which works in the kW scale. The reformer was operated under conditions of start-up, steady state and under dynamic conditions, in connection with a 1 kW high temperature PEM fuel cell and finally integrated into a fuel processor, which contained an external evaporator and a heat-exchanger for super-heating the reformer feed. The thermal power of the hydrogen produced by the reformer amounted to 20 kWthermal, which corresponds to 6.5 kWel of a fuel cell at 40% efficiency and 80% hydrogen utilization.

Ni-based (over MgO and Al 2 O 3 ) and noble metal-based (Pd and Pt over Al 2 O 3 ) catalysts were prepared by wet impregnation method and thereafter impregnated in microreactors. The catalytic activity was measured at several temperatures, atmospheric pressure and different steam to carbon, S/C, ratios. These conditions were the same for conventional, fixed bed reactor system, and microreactors. Weight hourly space velocity, WHSV, was maintained equal in order to compare the activity results from both reaction systems. For microreactor systems, similar activities of Ni-based catalyst were measured in the steam methane reforming (SMR) activity tests, but not in the case of natural gas steam reforming tests. When noble metal-based catalysts were used in the conventional reaction system no significant activity was measured but all catalysts showed some activity when they were tested in the microreactor systems. The analysis by SEM and TEM revealed a carbon-free surface for Ni-based catalyst as well as carbon filaments growth in case of noble metal-based catalysts.