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  • 1.
    Bergman, Susanna L
    et al.
    Princeton University, Science Division, Yale-NUS College, Singapore.
    Granestrand, Jonas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Tang, Yu
    University of Kansas.
    Suárez Paris, Rodrigo
    Scania CV.
    Nilsson, Marita
    Scania CV.
    Feng Tao, Franklin
    University of Kansas.
    Tang, Chunhua
    National University of Singapore.
    Pennycook, Stephen J
    National University of Singapore.
    Pettersson, Lars J
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Bernasek, Steven L
    Princeton University, Science Division, Yale-NUS College, Singapore.
    In-situ characterization by Near-Ambient Pressure XPS of the catalytically active phase of Pt/Al2O3 during NO and CO oxidation2018In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 220, p. 506-511Article in journal (Refereed)
    Abstract [en]

    This study concerns near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) studies of a Pt/Al2O3 diesel oxidation catalyst used in exhaust aftertreatment. We apply the technique to an industrial-grade porous catalyst, thus bridging both the pressure and materials gap, and probe the shift in binding energy of Pt 4d under different atmospheres. We observe that oxidizing atmospheres induce a shift in binding energy, corresponding to changes in Pt oxidation state, especially pronounced under an atmosphere of NO and O2. Such changes in Pt oxidation state have previously been linked to dynamic changes in NO oxidation activity.

  • 2. Creaser, Derek
    et al.
    Karatzas, Xanthias
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lundberg, Bjorn
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Dawody, Jazaer
    Modeling study of 5 kW(e)-scale autothermal diesel fuel reformer2011In: Applied Catalysis A: General, ISSN 0926-860X, E-ISSN 1873-3875, Vol. 404, no 1-2, p. 129-140Article in journal (Refereed)
    Abstract [en]

    A model was developed that successfully describes key operating features of a 5 kW(e)-scale autothermal diesel fuel reformer with an engineered monolith-supported Rh based catalyst. The model consisted of a kinetic model comprised of four overall reactions including total oxidation, fuel steam reforming, methane formation via fuel decomposition and the water-gas shift reaction. The model also accounted for heat and mass transport effects that were of importance when coupling the exothermic oxidation reactions with endothermic steam reforming reactions in a full-scale reformer. According to the model, the total oxidation and steam reforming reactions occurred simultaneously, however the heat effects of the oxidation reaction dominated near the reactor inlet resulting in a local hot spot. Transport resistances were found to hinder the rates of the main reactions, especially at higher temperature operating conditions. The model was primarily based on experimental data for a commercial low-sulphur diesel fuel (MK1), however it was found to also reasonably well describe the operation of the reactor with a diesel surrogate (n-tetradecane).

  • 3. Creaser, Derek
    et al.
    Nilsson, Marita
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Dawody, Jazaer
    Kinetic Modeling of Autothermal Reforming of Dimethyl Ether2010In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 49, no 20, p. 9712-9719Article in journal (Refereed)
    Abstract [en]

    A global kinetic model was developed for the autothermal reforming of dimethyl ether (DME) over a Pd-Zn/Al2O3 catalyst on a cordierite monolith. A kinetic model consisting of five key overall reactions was found to capture the main features of experimental data. The modeling also accounted for heat transport effects in the reactor that are of importance when coupling the exothermic oxidation reactions with endothermic steam reforming reactions. The modeling confirmed that oxidation reactions dominate near the inlet of the reactor, generating a local hot spot. The heat from oxidation reactions accelerates the reforming reactions. Water adsorption was found to have a weak detrimental influence on the activity. On the basis of the model, the influence of the reactor scale and oxygen supply by air feed on the performance of the reactor was examined.

  • 4.
    Dahlin, Sandra
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Lantto, Cornelia
    Luleå University of Technology, Knightec AB.
    Englund, Johanna
    Chalmers University of Technology.
    Westerberg, Björn
    Scania CV.
    Regali, Francesco
    Scania CV.
    Skoglundh, Magnus
    Chalmers University of Technology.
    Pettersson, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Chemical aging of Cu-SSZ-13 SCR catalysts for heavy-duty vehicles –Influence of sulfur dioxide2018In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 320, p. 72-83Article in journal (Refereed)
    Abstract [en]

    Selective catalytic reduction of nitrogen oxides is an efficient technique for emission abatement in heavy-dutyvehicles. Cu-SSZ-13 SCR catalysts are more active than vanadium-based catalysts at low temperatures, but aremore sensitive to deactivation by sulfur. Consequently, there is a need to study poisoning by sulfur for thiscatalyst material. This experimental investigation focuses on the effect of sulfur on the low-temperature per-formance of Cu-SSZ-13 SCR catalysts. The effect of sulfur exposure temperature, and the influence of the NO 2 /NO x ratio, are considered and two different regeneration temperatures are compared. In addition, catalystsamples from an engine-aged catalyst are evaluated. The SO 2 exposure temperature is shown to have an im-portant impact on the deactivation of the Cu-SSZ-13 catalyst. The lowest sulfur exposure temperature (220 °C)results in the most severe deactivation, while the highest temperature during sulfur exposure (400 °C) results inthe lowest degree of deactivation. This was found to be related to the amount of sulfur on the catalyst.Additionally, SO 2 exposure was shown to decrease the N 2 O selectivity. The engine-aged catalyst has a decreasedperformance in terms of both decreased activity and increased N 2 O selectivity. For this catalyst, impurities fromfuel and engine-oil can play a role in the deactivation. Different deactivation mechanisms are seen for the lab-and engine-aged catalysts.

  • 5.
    Dahlin, Sandra
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Nilsson, Marita
    Backstrom, Daniel
    Bergman, Susanna Liljegren
    Bengtsson, Emelie
    Bernasek, Steven L.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology. Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University, Stellenbosch, South Africa.
    Multivariate analysis of the effect of biodiesel-derived contaminants on V2O5-WO3/TiO2 SCR catalysts2016In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 183, p. 377-385Article in journal (Refereed)
    Abstract [en]

    This study investigates the effect of biodiesel-derived contaminants on vanadia-based NH3-SCR catalysts in heavy-duty exhaust aftertreatment. The aim was to study, not only the effect of single contaminants on the catalyst performance, but also of possible interaction effects between poisons. The effect of six potential catalyst poisons (Na, K, Mg, P, S and Zn) was evaluated using an experimental design and multivariate data analysis. Monolithic V2O5-WO3/TiO2 catalysts were subjected to accelerated laboratory-scale aging, where the six contaminants were fed simultaneously using a wet impregnation method. In addition to NO conversion tests, the catalysts were characterized by means of ICP-OES, SEM-EDX, XPS, N-2 physisorption and NH3-TPD. The lab-aged samples were compared to fresh and vehicle-aged catalysts. The accelerated aging method showed good reproducibility and gave rise to surface compounds similar to those found in vehicle-aged catalysts. Despite plausible differences regarding penetration depth of the contaminants into the walls of the catalyst, the aging method appears to be an efficient way to point out significant chemical poisons. The model obtained from the experimental design was found to correlate well with the experimental data and can therefore be used to predict effects of the various poisons and poison interactions. Significant effects on the NOx conversion were found for P, S, Na, Mg and K as well as for the interactions P x Na, P x K and S x Na. A poisoning effect was found for Mg, Na, K, P x K, and P x Na, where Na and K exhibited the strongest poisoning effect. The deactivating effect of alkali was lowered in the presence of phosphorus and sulfur, which is explained by the formation of phosphates and sulfates, preventing the interaction of the alkali metals with the vanadia active sites.

  • 6. Edvardsson, J.
    et al.
    Westberg, H.
    Dawody, J.
    Andersson, L.
    Milh, M.
    Ingelsten, H. H.
    Kannisto, H.
    Gunnarsson, F.
    Palmqvist, A.
    Heijl, R.
    Ma, Y.
    Cederkrantz, D.
    Andersson, R.
    Högblom, O.
    Pettersson, Lars. J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Karatzas, Xanthias
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Ziethén Granlund, Moa. Z.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Larsson, P. -O
    Holmgren, L.
    Andreasson, F.
    E4-Mistra, a research program for the development of an energy efficient low emission exhaust aftertreatment system for heavy duty vehicles2012In: World Renewable Energy Forum, WREF 2012, Including World Renewable Energy Congress XII and Colorado Renewable Energy Society (CRES) Annual Conference, American Solar Energy Society , 2012, p. 4530-4536Conference paper (Refereed)
    Abstract [en]

    This paper presents a unique system approach applied in a joint academic - industrial research program, E4 Mistra, to reach the goals of energy efficiency and low emissions exhaust aftertreatment system for heavy duty vehicles. The high energy efficiency is achieved by heat recuperation, on-board hydrogen production for use in both an auxiliary power unit and for NOx reduction and by finding new solutions for making the after-treatment system active at low exhaust temperatures. To reach low particulate emissions a mechanical filter using a sintered metal filter is developed. Low NOx emissions are achieved by an efficient NOx reduction catalyst. The system is based on four technological advances: Thermoelectric material s for heat recuperation, catalytic reduction of NOx over innovative catalyst substrates using hydrocarbons from the fuel and H2 from a high efficiency fuel reformer, and particulate filtration over a porous metal filter.

  • 7.
    Engvall, Klas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Kusar, Henrik
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Sjöström, Krister
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Upgrading of raw gas from biomass and waste gasification: Challenges and opportunities2011In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 54, no 13-15, p. 949-959Article, review/survey (Refereed)
    Abstract [en]

    The depletion of fossil fuel-based resources and concerns for increasing emissions of CO2 call for newways of producing environmentally- friendly substitutes for motor fuels and chemicals. Thermo-chemical conversion of biomass andwaste using gasification is a strong candidate tomeet these challenges. For efficient and cost-effective application of this technique, novel solutions for hot gas cleaning are needed. This review highlights some important areas for improvement of upgrading technologies for pressurised fluidised bed gasification systems using biomass as a fuel.

  • 8.
    Gonzalez, Angelica V.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Karatzas, Xanthias
    Scania CV AB.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Autothermal reforming of Fischer-Tropsch diesel over alumina and ceria-zirconia supported catalysts2013In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 107, p. 162-169Article in journal (Refereed)
    Abstract [en]

    Autothermal reforming (ATR) of synthetic Fischer-Tropsch diesel has been carried out to evaluate the fuel reformer and the catalyst performance at realistic operating conditions. Hydrogen was produced via ATR in a full-scale reformer (ID = 84 mm, L = 400 mm) at 650-750 degrees C. The two monolithic catalysts were sequentially located in the reformer and simultaneously tested. The catalysts were composed of 1:1 wt% Rh:Pt as active metals; CeO2, MgO, Y2O3, and La2O3 were used as promoters. The first catalytic monolith was supported on delta-Al2O3 and the second on CeO2-ZrO2. Fresh samples were characterized by N-2-BET, XRD and H-2-TPR analyses. Catalyst activity was evaluated at O-2/C similar to 0.34-0.45 and H2O/C similar to 2-3. Results show an increased catalyst activity after the second monolithic catalyst due to the effect of steam reforming, water-gas shift reaction (WGS) and higher catalyst reducibility of RhxOy species on the CeO2-ZrO2 mixed oxide as a result of the improved redox properties. Hydrogen concentrations of 42 vol% and fuel conversion of 98% after the CeO2-ZrO2-supported catalyst was obtained at O-2/C = 0.42 and H2O/C = 2.5.

  • 9.
    Gonzalez, Angelica V.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Full-scale autothermal reforming for transport applications: The effect of diesel fuel quality2013In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 210, p. 19-25Article in journal (Refereed)
    Abstract [en]

    This study evaluates the feasibility of H-2 production through a fuel flexible reformer, at realistic operating conditions for electricity supply by FC-APUs in the transport sector. The fuel flexibility is evaluated by comparison of autothermal reforming performance with biodiesel (RME), Fischer-Tropsch, low-sulfur diesel (MK1) and European standard diesel (DIN 590). ATR experiments with two monolithic catalysts, Rh1.0Pt1.0Ce10La10/Al2O3 (CAT 1) and Rh1.0Pt1.0Mg4.0Y5.0/CeO2-ZrO2 (CAT 2), sequentially placed in the axial direction of the reformer length were used for full-scale tests. The O-2/C ratio was varied from 0.3 to 0.5 and the H2O/C ratio varied from 2 to 3.5, reaching temperatures in the interval of 700-800 degrees C. The hydrogen production and fuel conversion showed an upward trend from RME < DIN 590 < MK1 < FT with maximum 42 vol.% H-2 and 99% fuel conversion for FT diesel.

  • 10.
    González Arcos, Angélica Viviana
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Rostrup-Nielsen, J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Engvall, Klas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Promoted RhPt bimetallic catalyst supported on δ-Al2O3 and CeO2-ZrO2 during full-scale autothermal reforming for automotive applications: Post-mortem characterization2015In: Applied Catalysis A: General, ISSN 0926-860X, E-ISSN 1873-3875, Vol. 491, p. 8-16Article in journal (Refereed)
    Abstract [en]

    The influence of sulfur and coke formation on the steam reforming of diesel was evaluated for two promoted RhPt bimetallic catalysts, composed of 1:1 Rh:Pt/10:10 La2O3: CeO2/ δ-Al2O3 (CAT 1) and 1:1 Rh:Pt/4:5 MgO: Y2O3/CeO2 − ZrO2 (CAT 2). The intrinsic activity is related to the total Rh and Pt area observed after the exposure to sulfur. Therefore, the degree of deactivation is related to the amount of sulfur deposited on the active metal sites. Sulfur analysis on the aged catalyst washcoat showed a decreasing sulfur concentration in the axial direction of the reformer. The estimated sulfur coverage related to metal surface area after 40 h on stream reached values of 0.145 in CAT 2, below the equilibrated sulfur coverage of 0.19 after tests with DIN 590. Thus, showing a partial deactivation due to sulfur poisoning. Further catalyst characterization on carbon deposits and thermal aging was performed by TPO, TGA, BET, CO chemisorption, and TEM analysis.

  • 11.
    Granlund, Moa Z.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Görke, Oliver
    Pfeifer, Peter
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Comparison between a micro reactor with multiple air inlets and a monolith reactor for oxidative steam reforming of diesel2014In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 39, no 31, p. 18037-18045Article in journal (Refereed)
    Abstract [en]

    Abstract In order to lower the emission from idling heavy-duty trucks auxiliary power units can be implemented. Due to limited space available on-board the truck the units needs to be both efficient and compact. One alternative for these units is a fuel cell supplied with hydrogen from a fuel reformer. Today, mostly monolithic reactors are used in the field of oxidative steam reforming of fuels, which has some challenges that need to be addressed before a possible breakthrough occurs on the market. One is the temperature gradient developed over the length of the monolith as a consequence of the sequential reactions. This could be improved by using a metallic micro reactor with better heat integration between the reaction zones and further improving the integration with multiple air inlets along the catalytic bed. The aim with this study was to compare a conventional monolith reactor for oxidative steam reforming of fuel with a novel micro reactor design where air was dosed at four different positions along the reactor channels. The experiments were not necessarily conducted autothermal, i.e. a heating jacket was applied for operation.

  • 12.
    Granlund, Moa Z.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Jansson, Kjell
    Stockholm University, Arrhenius Laboratory, Department of Materials and Environmental Chemistry.
    Nilsson, Marita
    Scania CV AB, Materials Technology, Engine Performance and Emissions.
    Dawody, Jazaer
    Volvo Group Trucks Technology, Advanced Technology & Research, Energy Efficiency & Environmen.
    Pettersson, Lars. J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Evaluation of Co, La, and Mn promoted Rh catalysts for autothermal reforming of commercial diesel2014In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 154, p. 386-394Article in journal (Refereed)
    Abstract [en]

    The objective of this paper was to study the influence three promoters (Co, La, Mn) had on the catalytic activity of Rh-based catalysts for autothermal reforming of diesel. The catalysts were supported on CeO2ZrO2 and the loading was 1 wt.% Rh and 6 wt.% promoter. The catalytic activity was evaluated in a monolith bench scale reactor with Swedish Environmental diesel, MK1. The process parameters employed at the ATR experiments were; O-2/C similar to 0.45, H2O/C similar to 2.5 and GHSV similar to 50,000h(-1), meanwhile the reactor temperature was ramped from 700 degrees C to 950 degrees C. The catalysts were compared based on their fuel conversion, H-2 yield and the selectivity of different short-chain hydrocarbons. The results showed that all three catalysts had both high fuel conversion and H-2 yield in the optimal ATR operation temperatures. The H-2 yield and fuel conversion were increasing in the order Rh/Mn, Rh/La, Rh/Co. To get further insight in the difference between the materials the fresh and aged catalytic materials were characterized. The characterization methods used were H-2-temperature programmed reduction (H-2-TPR), powder X-ray diffraction (XRD), and BET surface measurements. The BET surface measurements showed that promotion with La gave improved thermal stability of the material. The XRD showed a high dispersion of all metals except Co, which was present as crystals in the size range of the particles of the support.

  • 13.
    Granlund, Moa Z.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Jansson, Kjell
    Stockholm University.
    Nilsson, Marita
    Dawody, Jazaer
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Evaluation of Co, La, and Mn promoted Rh catalysts for autothermal reforming of commercial diesel: Aging and characterization2015In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 172, p. 145-153Article in journal (Refereed)
    Abstract [en]

    In this study three bimetallic catalysts are evaluated for autothermal reforming (ATR) of fuels (1 wt.% Rh and 6 wt.% X (X = Co, La or Mn) supported on high-surface area CeO2-ZrO2). The catalysts are aged for approximately 35 h and carefully characterized both as fresh and aged materials. The objective is to illuminate the changes in material properties after time on stream as well as the differences among the materials. The changes in material properties are evaluated by H2-TPR, BET surface area analysis, TEM, SEM and STEM. The material’s tendency to coke is investigated by TPO analysis.

    The three materials exhibit promising initial activity. However, the Co-promoted sample decreases sharply in activity after 25 h of operation. Meanwhile, the other two materials display a more stable activity throughout the evaluated time. The deactivation of the Co-promoted material could be linked to the high amount of coke deposited during operation. Based on the results from the activity evaluation and characterization, the material promoted with lanthanum displays the most promising results. The addition of lanthanum resulted in a catalyst that was both stable and had high activity, even though a low rhodium loading is used. The material also shows superior thermal resistance compared to the other two materials. In addition, the tendency to coke is significantly lower compered to the other materials, which is especially beneficial when dealing with ATR of complex fuels. 

  • 14.
    Granlund, Moa Z.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Zacherl, Sabina
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology. Univ Stellenbosch, South Africa.
    Comparison between ceria-zirconia and alumina as supports for oxidative steam reforming of biodiesel2015In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 58, no 14-17, p. 933-938Article in journal (Other academic)
    Abstract [en]

    The objective of the study is to illustrate the advantages with using ceria–zirconia instead of promoted alumina as support for rhodium-based catalysts in oxidative steam reforming of biodiesel. The evaluation is based on long-term oxidative steam reforming experiments where the stability and durability of the catalysts are evaluated. The durability and fuel conversion of the two catalysts were comparable. However, the H2 yield of the ceria–zirconia supported catalyst was 10 % higher than for the catalyst supported on promoted alumina after 65 h on stream. Included are also measurements of the acidity of the catalysts, where it was concluded that the promoted alumina catalyst was significantly more acidic. The acidity of the materials could then be related to the amount of coke deposited, where the amount of coke on the alumina catalyst was almost five times higher after 50 h of operation compared to the ceria–zirconia catalyst.

  • 15.
    Gunnarsson, Fredrik
    et al.
    Chalmers Tekniska Högskola.
    Granlund, Moa. Z.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Englund, Mattias
    Chalmers Tekniska Högskola.
    Dawody, Jazaer
    Pettersson, Lars. J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Härelind, Hanna
    Chalmers Tekniska Högskola.
    Combining HC-SCR over Ag/Al2O3 and hydrogen generation over Rh/CeO2-ZrO2 using biofuels: An integrated system approach for real applications2015In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 162, p. 583-592Article in journal (Refereed)
    Abstract [en]

    Abstract We report on a high NOx reduction activity over Ag/Al2O3 catalysts, using hydrogen produced in a fuel reformer. The focus of the study is to evaluate the performance of a hydrocarbon selective catalytic reduction (HC-SCR) catalyst in real conditions. Initially, the catalytic materials for the fuel reformer (Rh/CeO2-ZrO2) and the HC-SCR (Ag/Al2O3) were evaluated in separate bench-scale reactor setups. These two setups were subsequently joined into an integrated bench-scale reactor setup with the aim to evaluate the influence of the reformate on the HC-SCR activity in a controlled environment. In the final phase of the study a 4 wt.% Ag/Al2O3 catalyst doped with 100 ppm(w) Pt was scaled up and tested in a pilot-scale reactor setup. The pilot-scale reactor setup enabled evaluation of the HC-SCR activity in real exhaust gases generated by a single cylinder engine (genset) together with a hydrogen-rich gas supplied from a fuel reformer. Commercial biodiesel (NExBTL) was used as reducing agent for the HC-SCR as well as fuel in the fuel reformer for both the bench-scale and pilot-scale experiments. This study gives an excellent link between evaluations of the catalytic materials, controlled bench-scale experiments and applied engine experiments, proving a viable concept for lean NOx reduction together with onboard hydrogen production. A NOx conversion of above 70% was reached at temperatures below 250 °C, in bench-scale experiments when hydrogen produced in the fuel reformer is added.

  • 16. Kannisto, H.
    et al.
    Karatzas, Xanthias
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Edvardsson, J.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Ingelsten, H. H.
    Efficient low temperature lean NOx reduction over Ag/Al2O3-A system approach2011In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 104, no 1-2, p. 74-83Article in journal (Refereed)
    Abstract [en]

    This study focuses on lean NOx reduction (LNR) by n-octane using silver-alumina based catalysts, with the addition of hydrogen. The work takes a system approach, where parameters such as temperature, reformate gas composition, fuel penalty and realistic monolith samples are considered. The LNR catalyst samples were prepared by impregnation and sol-gel methods and the NOx reduction performance was characterized by flow-reactor experiments, where realistic engine-out gas compositions were used. The hydrogen feed over the LNR catalyst samples was determined via data achieved by autothermal reforming experiments over a rhodium based catalyst, using real diesel as feedstock. The LNR catalyst samples generally show an enhanced NOx reduction when hydrogen is added to the gas feed. In particular, a 2 wt% silver-alumina sample with the addition of minute amounts of platinum, shows a high increase in NOx reduction when hydrogen is added to the feed. The addition of CO, a potential poison in the reaction and a by-product from the reforming, did not show any significant effect on the LNR catalyst performance at the conditions used. This is beneficial, since it renders a CO clean-up step in the reformer system unneeded. Ammonia formation is discussed in terms of a possible dual-SCR system. Finally, the fuel penalty for hydrogen production and hydrocarbon addition is taken into consideration. It is found that an addition of 1000 ppm H-2 leads to unacceptable fuel penalties.

  • 17.
    Karatzas, Xanthias
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Creaser, Derek
    Volvo Technology.
    Grant, Ann
    Volvo Technology.
    Dawody, Jazaer
    Volvo Technology.
    Pettersson, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Hydrogen generation from n-tetradecane, low-sulfur and Fischer-Tropsch diesel over Rh supported on alumina doped with ceria/lanthana2011In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 164, no 1, p. 190-197Article in journal (Refereed)
    Abstract [en]

    The present study demonstrates the use of rhodium-based monolithic catalyst for onboard reforming of diesel fuels. Experimental results from hydrogen generation of n-tetradecane, low-sulfur and Fischer-Tropsch diesel, via autothermal reforming (ATR), were acquired with a catalyst consisting of 3 wt% Rh supported on alumina doped with Ce/La. The catalyst was prepared by impregnation using the incipient wetness technique, and deposited onto a 400 cpsi cordierite monolith. Furthermore, the catalyst was tested over ranges of oxygen-to-carbon and water-to-carbon feed ratios, both in a bench-scale and a full-scale reactor. Fresh powder samples of the catalyst were characterized by XRD, N(2)-BET, H(2) chemisorption, H(2)-TPR and XPS analyses. The activity results showed that high fuel conversions and hydrogen production could be achieved with 3 wt% Rh for all fuels. Furthermore, the highest formation of CO and C(2)H(4) was found in the product gas stream from the low-sulfur diesel. In addition, partial oxidation and steam reforming reactions were identified by closely studying the distribution of the analyzed product gas composition and the temperature measurements. The characterization results showed the presence of finely dispersed Rh particles in the support. Furthermore, bulk and surface rhodium oxides were detected, which have been suggested to be one of the major active phases for ATR of diesel. Bulk and surface cerium oxides (CeO(2)) and surface La in the dispersed phase were also found to be present in the catalyst composition. These promoters are believed to improve the catalyst activity and durability.

  • 18.
    Karatzas, Xanthias
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Dawody, Jazaer
    Grant, Ann
    Svensson, Erik Elm
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Zone-coated Rh-based monolithic catalyst for autothermal reforming of diesel2011In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 101, no 3-4, p. 226-238Article in journal (Refereed)
    Abstract [en]

    In this work we present results of hydrogen generation from diesel via autothermal reforming (AIR) obtained with monolithic catalysts consisting of either one or two layers of monometallic Rh and bimetallic RhPt washcoats. The Rh metal loading of the monometallic washcoats was varied between 0.5, 1.0 and 3.0 wt%, while the weight ratio of Rh:Pt in the bimetallic washcoats was kept constant at 1:1. Furthermore, non-doped and CeLa-doped catalysts were also tested to detect differences in catalyst activity. The catalysts consisting of two layers of washcoats were termed zoned catalysts and each layer was applied to some given length in the axial direction of the monolith. All catalysts were prepared by impregnation using the incipient wetness technique with delta-Al2O3 B as support and deposited onto 400 cpsi cordierite monoliths. A total of eight catalysts, including both single layered and zone-coated, were tested in a bench-scale reactor using low-sulfur diesel as fuel at operating conditions H2O/C=2.5, O-2/C=0.49 (lambda = 0.33), GHSV 17,000 h(-1) and P = 1 atm. The results showed that the zoned catalyst, covered with the two washcoats Rh1.0Pt1.0-Ce10La5.0/delta-Al2O3 and Rh-3.0-Ce10La10/delta-Al2O3, respectively, was most active in terms of fuel conversion and hydrogen production. The zoned catalyst's long-term performance and stability was also evaluated in a full-scale reactor using low-sulfur and Fischer-Tropsch diesels at operating conditions H2O/C = 2.5, O-2/C = 0.49 (lambda =0.33), GHSV= 10,800 h(-1), P = 1 atm, and at H2O/C = 2.4, 02/C = 0.39 (lambda=0.26), GHSV- 10,200 h(-1), P = 1 atm. respectively. The results showed that high fuel conversion and hydrogen production were obtained from both fuels. In addition, partial oxidation and steam reforming reactions were identified by closely studying the distribution of the analyzed product gas composition and the temperature measurements. Fresh and aged samples of the catalysts were characterized by N-2-BET, H-2 chemisorption, XRD, H-2-TPR, O-2-TPO and XPS analyses.

  • 19.
    Karatzas, Xanthias
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Jansson, Kjell
    Stockholm University.
    Dawody, Jazaer
    Volvo Technology.
    Lanza, Roberto
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Microemulsion and incipient wetness prepared Rh-based catalyst for diesel reforming2011In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 175, no 1, p. 515-523Article in journal (Refereed)
    Abstract [en]

    The role of the catalyst preparation technique was investigated for diesel reforming. Reverse microemulsion (ME) and incipient wetness (IW) techniques were used for the preparation of Rh-based monolithic catalysts that were employed for hydrogen generation of low-sulfur diesel via autothermal reforming (ATR). The washcoat of the tested catalysts consisted of 0.5 wt% Rh, 1 wt% Rh, and 1: 1 wt% Rh: Pt supported on gamma-alumina. All washcoats were deposited on 400 cpsi cordierite monoliths. The reaction condition was T(feed) = 650 degrees C, H(2)O/C similar to 2.5, O(2)/C similar to 0.49, TOS = 3 h, GHSV similar to 13 000 h(-1) and P = 1 atm. Fresh and aged powder samples of the catalyst were characterized by N(2)-BET, H(2) chemisorption, XRD, H(2)-TPR, O(2)-TPO and TEM. The activity results established that Rh and RhPt formulations, prepared by ME and IW, are highly active for ATR of diesel where fuel conversions above 92% were obtained. FTIR and NDIR analysis also showed that the highest formation of ethylene was found in the product gas stream from the bimetallic samples indicating that RhPt/Al(2)O(3) is less resistant towards carbon deposition. The latter observation was confirmed by O(2)-TPO analysis of the aged samples where high loads of coke were found both on the active metals and on the support. Interestingly, these effects were less significant on the ME samples. The characterization results clearly showed differences in morphology between the ME and the IW samples. N(2)-BET analysis showed that higher surface area, similar to 268-285 m(2)/g, was obtained with the ME samples. Also, H(2) chemisorption analysis showed that the rhodium dispersion was similar to 10% higher for the ME samples (H/Rh similar to 60-66%). XRD analysis showed that crystalline phases of gamma-alumina were present on all samples. The diffractograms also showed small traces of metallic Pt (similar to 16-30 nm) in the bimetallic samples. H(2)-TPR analysis, showed peaks ascribed to bulk rhodium oxides and rhodium aluminates. It was also noted that the addition of Pt on the support lowered the reducibility of the different rhodium species. TEM analysis performed on the fresh and aged ME and IW bimetallic samples showed mainly Rh(x)Pt(1-x) alloys with an average particle size of similar to 20-50 nm were present on the alumina support. Also, for the aged samples, no sintering effects were noted. Furthermore, rhodium was found to switch oxidation state from e. g. Rh(3+) to Rh(0) while Pt remained in the metallic state.

  • 20.
    Karatzas, Xanthias
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Jansson, Kjell
    Stockholm University.
    González, Angélica
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Dawody, Jazaer
    Volvo Technology.
    Pettersson, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Autothermal reforming of low-sulfur diesel over bimetallic RhPt supported on Al2O3, CeO2-ZrO2, SiO2 and TiO22011In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 106, no 3-4, p. 476-487Article in journal (Refereed)
    Abstract [en]

    The objective of this paper is to study and clarify the role of selected supports (both reducible and non-reducible) on the activity, selectivity and stability of RhPt-based catalyst for diesel reforming. Autothermal reforming (AIR) of low-sulfur diesel (S similar to 6 ppm, C/H similar to 6.43 (w/w)), H(2)O/C similar to 2.5, O(2)/C similar to 0.49, was tested at bench scale to detect differences in activity for catalysts consisting of 1 wt% Rh and 1 wt% Pt supported on alumina, ceria-zirconia (17.5 wt% ceria), silica and titania. Promoters in the form of MgO. Y(2)O(3), La(2)O(3), CeO(2) and ZrO(2), ranging from 4 wt% to 10 wt%, were also added onto the supports to detect differences in catalyst activity in terms of diesel conversion, CO(2) selectivity, and hydrogen and ethylene production. All metals were added sequentially onto the support by the incipient wetness technique and washcoated on 400 cpsi cordierite monolithic carriers with dimensions d = 17.8 mm, l=30.5 mm.

    The product gas analysis, using FTIR and NDIR, showed that RhPt/CeO(2)-ZrO(2) was found to be most active for AIR of diesel since a fuel conversion close to 98% was obtained. Furthermore, the catalyst activity of the unpromoted samples, in terms of diesel conversion, increased in the following order: RhPt/SiO(2) < RhPt/TiO(2) < RhPt/Al(2)O(3) < RhPt/CeO(2)-ZrO(2). The addition of promoters was found to be insignificant as well as having a negative impact on the catalyst performance in most cases, except for the alumina-promoted sample. The addition of 10 wt% La(2)O(3) on RhPt/Al(2)O(3) was found to enhance diesel conversion, hydrogen productivity as well as lower the ethylene concentration from 3700 ppm to less than half that value. The latter observation was confirmed by O(2)-TPO analysis of aged powder samples where lower loads of coke were present than on the La-promoted sample.

    The morphology, surface and bulk properties of RhPt/CeO(2)-ZrO(2) were closely examined in order to provide a possible correlation between the activity and characterization results. N(2)-BET analysis showed that the surface area of RhPt/CeO(2)-ZrO(2) was 64 m(2)/g, while the silica samples exhibited the highest area, similar to 137-185 m(2)/g. Hence, the difference in the surface areas was not enough to explain the trends observed in the activity measurements. XRD analysis of RhPt/CeO(2)-ZrO(2) showed crystalline phases characteristic of zirconia, most likely tetragonal. Also, the diffractogram did not reveal any Rh or Pt peaks indicating that the noble metal particles are highly dispersed on the support. In contrast, peaks ascribed to metallic Pt (similar to 30-46 nm) were clearly visible on the XRD patterns taken from all the other supported samples. H(2)-TPR analysis of RhPt/CeO(2)-ZrO(2) showed reduction peaks ascribed to Rh(i)O(x) species as well as a minor hydrogen spillover effect on the support to be present at T=120 degrees C and 450 degrees C, respectively. Also, the hydrogen consumption of the Rh(i)O(x) species was the highest compared to the other supported RhPt samples. TEM analysis performed on fresh RhPt/CeO(2)-ZrO(2) showed that the Rh(i)O(x) and Pt particles were highly dispersed on the support, both with particle sizes in the vicinity of similar to 5-15 nm. Rh species was found on ceria and zirconia, while Pt was present mainly on the ceria layer possibly in the form of Pt-O-Ce bonds. H(2)-chemisorption analysis measured at T similar to 40 degrees C shows similar Rh dispersion results.

    To summarize, the higher activity results of RhPt/CeO(2)-ZrO(2) for AIR of diesel, compared to other supported catalysts, may be ascribed to the higher reducibility of Rh(i)O(x) species as well as the superior Rh and Pt dispersion. Also, the support contribution, in particular ceria, is believed to promote water gas-shift activities as well as reduce coke deposits on the catalyst surface.

  • 21.
    Karatzas, Xanthias
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Nilsson, Marita
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Dawody, Jazaer
    Lindström, Bard
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Characterization and optimization of an autothermal diesel and jet fuel reformer for 5 kW(e) mobile fuel cell applications2010In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 156, no 2, p. 366-379Article in journal (Refereed)
    Abstract [en]

    The present paper describes the characterization of an autothermal reformer designed to generate hydrogen by autothermal reforming (ATR) from commercial diesel fuel (similar to 10 ppm S) and jet fuel (similar to 200 ppm S) for a 5 kW(e) polymer electrolyte fuel cell (PEFC). Commercial noble metal-based catalysts supported on 900 cpsi cordierite monoliths substrates were used for ATR with reproducible results. Parameters investigated in this study were the variation of the fuel inlet temperature, fuel flow and the H2O/C and O-2/C ratios. Temperature profiles were studied both in the axial and radial directions of the reformer. Product gas composition was analyzed using gas chromatography. It was concluded from the experiments that an elevated fuel inlet temperature (>= 60 degrees C) and a higher degree of fuel dispersion, generated via a single-fluid pressurized-swirl nozzle at high fuel flow, significantly improved the performance of the reformer. Complete fuel conversion, a reforming efficiency of 81% and an H-2 selectivity of 96% were established for ATR of diesel at P=5kW(e), H2O/C = 2.5, O-2/C = 0.49 and a fuel inlet temperature of 60 degrees C. No hot-spot formation and negligible coke formation were observed in the reactor at these operating conditions. The reforming of jet fuel resulted in a reforming efficiency of only 42%. A plausible cause is the coke deposition, originating from the aromatics present in the fuel, and the adsorption of S-compounds on the active sites of the reforming catalyst. Our results indicate possibilities for the developed catalytic reformer to be used in mobile fuel cell applications for energy-efficient hydrogen production from diesel fuel.

  • 22.
    Lanza, Roberto
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Eriksson, E.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    NOx selective catalytic reduction over supported metallic catalysts2009In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 147, p. S279-S284Article in journal (Refereed)
    Abstract [en]

    In this work we present the results obtained with 3 catalysts (Pt, Rh and Ag on alumina) tested in ranges of temperatures and gas hourly space velocities typical of diesel engines in real trucks. NO concentration was 500 ppm, C3H6 ranged between 500 and 2000 ppm, while oxygen was always 5%. All the catalysts were active and showed high conversions. Both Pt and Rh were active at low temperature (T-50 = 200-250 degrees C) but had quite high selectivity towards NO2. Silver was active at higher temperature, but showed very high selectivity towards N-2. A strong boosting effect on NO conversion was recorded if H-2 was added to the gas mixture.

  • 23. Lilja, J.
    et al.
    Warna, J.
    Salmi, T.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Ahlkvist, J.
    Grenman, H.
    Ronnholm, M.
    Murzin, D. Y.
    Esterification of propanoic acid with ethanol, 1-propanol and butanol over a heterogeneous fiber catalyst2005In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 115, no 02-jan, p. 1-12Article in journal (Refereed)
    Abstract [en]

    Esterification kinetics of propanoic acid with ethanol, 1-propanol and butanol over a fibrous polymer-supported sulphonic acid catalyst (Smopex-101) was studied. Experiments were carried out in a batch reactor operating isothermally at three different temperatures: 60, 70 and 75 degrees C (80 degrees C for butanol) and with different initial molar ratios of propanoic acid and alcohol (1:1, 1:2 and 2:1). The fiber catalyst was active and stable in all the experiments. The experimental results were modeled according to a Langmuir-Hinshelwood model and with an advanced adsorption-based model. The activity coefficients were calculated according to the UNIFAC model. The activation energy of esterification of propanoic acid with ethanol was found to be 52.6 kJ/mol, 49.9 kJ/mol with 1-propanol and 47.3 kJ/mol with butanol. The kinetic model, which includes the adsorption of carboxylic acid and water combined with the activities of the species, explained the experimentally recorded concentrations well.

  • 24. Lindström, B.
    et al.
    Agrell, J.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Combined methanol reforming for hydrogen generation over monolithic catalysts2003In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 93, no 1, p. 91-101Article in journal (Refereed)
    Abstract [en]

    An experimental investigation on hydrogen generation from methanol using monolithic catalysts is presented in this paper. The activity and carbon dioxide selectivity for the reforming of methanol over various binary copper-based materials, Cu/Cr, Cu/Zn and Cu/Zr, have been evaluated. The methanol reforming was performed using steam reforming and combined reforming (CMR, a combination of steam reforming and partial oxidation). The CMR process was carried out at two modes of operation: near auto-thermal and at slightly exothermal conditions. The catalysts have been characterized using BET surface area measurement, X-ray diffraction (XRD), temperature programmed reduction (TPR) and scanning electron microscopy (SEM-EDS). The results show that the choice of catalytic material has a great influence on the methanol conversion and carbon dioxide selectivity of the reforming reaction. The zinc-containing catalyst showed the highest activity for the steam reforming process, whereas the copper/chromium catalyst had the highest activity for the CMR process. The copper/zirconium catalyst had the highest CO2 selectivity for all the investigated process alternatives.

  • 25. Lindström, B.
    et al.
    Karlsson, J. A. J.
    Ekdunge, P.
    De Verdier, L.
    Häggendal, B.
    Dawody, J.
    Nilsson, Marita
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Diesel fuel reformer for automotive fuel cell applications2009In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 34, no 8, p. 3367-3381Article in journal (Refereed)
    Abstract [en]

    Fuel economy and emission abatement are issues, which are highly prioritized areas in the automotive industry of today. The debate about climate change has in recent years even more emphasized the importance of these issues and has increased the search for finding sustainable technical solutions. This paper describes an effort to develop an innovative and environmentally-benign hydrogen generation system operating on commercial diesel fuel to avoid running the engine to supply electricity at stand-still. The use of a fuel cell-based auxiliary power unit (APU) has the potential of delivering electricity at high efficiencies independent of the heavy-duty truck engine. During the reformer development phase, spray formation and mixing of reactants proved to be crucial to obtain high reforming efficiencies and low diesel slip. The diesel is being injected through a nozzle creating a spray of fine droplets of a size which can establish rapid evaporation. Air and steam are being pre-heated and injected into the mixture chamber and subsequently mixed with the evaporated diesel fuel. Depending on the operating parameters, a part of the fuel is being oxidized and produces heat. Autothermal reforming was chosen to circumvent the heat transfer problem in catalytic steam reforming. By supplying heat directly to the catalyst surface by an oxidation reaction the heat demand of the strongly endothermic steam reforming reaction can be fulfilled. We employed CFD calculations, which revealed the importance of avoiding large recirculation zones leading to a prolonged residence time of the hydrocarbon molecules and causing auto-ignition and excessive temperatures in the catalyst. Five different reformer generations are being described and discussed in detail in this publication. The first one was based on a fixed bed reactor, while the other four all relied on catalytic monoliths enabling low pressure drops. The early reactor designs all suffered from auto-ignition and instability problems. The latter generations exhibited a considerably more stable temperature profile in the reformer. The conversion of diesel and the reformer efficiencies are significantly higher than the early generation diesel reformers.

  • 26. Lindström, B.
    et al.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    A brief history of catalysis2003In: CATTech, ISSN 1384-6566, E-ISSN 1572-8811, Vol. 7, no 4, p. 130-138Article in journal (Refereed)
    Abstract [en]

    Historical studies are usually divided into segments of time that were marked by intellectual progress or specific achievements. Some periods are clearly identified by great events or an individual accomplishment that revolutionizes the entire concept. However, in most cases the advancement from one period to another is not marked by distinct accomplishments, but rather the result of a series of advances. This paper follows this conventional style and we have divided our subject of catalysis into five distinct periods.

  • 27. Lindström, B.
    et al.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Catalytic oxidation of liquid methanol as a heat source for an automotive reformer2003In: Chemical Engineering & Technology, ISSN 0930-7516, E-ISSN 1521-4125, Vol. 26, no 4, p. 473-478Article in journal (Refereed)
    Abstract [en]

    A reactor for catalytically oxidizing liquid methanol has been developed for supplying heat to an automotive reformer. In the tests presented in this paper we show that it is possible to catalytically combust liquid methanol by dispersing the methanol and air by a nebulizer over the catalysts. In the experiments we tested several base and noble metals and found that either platinum or palladium was required at the ignition zone. The tests also showed that it was possible to achieve complete combustion when only 25% of the catalyst bed contained a noble metal.

  • 28. Lindström, B.
    et al.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Deactivation of copper-based catalysts for fuel cell applications2001In: Catalysis Letters, ISSN 1011-372X, E-ISSN 1572-879X, Vol. 74, no 02-jan, p. 27-30Article in journal (Refereed)
    Abstract [en]

    The activity of copper catalysts for the steam reforming of methanol was investigated under deactivating conditions. The effects of adding poisonous substances which can occur in the fuel, such as sulphur and chlorine, were studied. Thermal ageing by sintering was observed while exposing the catalyst to high temperatures. The catalyst activity for steam reforming was greatly affected by the addition of low concentrations of sulphur and chlorine. Sulphur was more detrimental to the catalyst than chlorine.

  • 29. Lindström, B.
    et al.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Development of a methanol fuelled reformer for fuel cell applications2003In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 118, no 02-jan, p. 71-78Article in journal (Refereed)
    Abstract [en]

    A compact methanol reformer for fuel cell vehicles (FCVs) has, been developed and successfully tested. The reformer which has been constructed to serve a 5 Me fuel cell operates by combined reforming of methanol (CRM) (a combination of steam reforming and partial oxidation). The exploitable energy surplus in a fuel cell vehicle is low and therefore a combustion system for heating the reformer which utilizes a catalyst for both evaporation and oxidation of liquid methanol was developed. We were able to obtain start-up times in the region of 4-6 min depending on the oxygen-to-methanol ratio (OMR) used for the combined reforming reaction. The main drawback from decreasing the start-up time by increasing the oxygen-to-methanol ratio was that the CO concentrations in the product stream increased. The reforming reaction was performed over copper-based catalysts while the oxidation took place over a mixture of platinum and manganese-based catalysts. The catalysts were characterized using SEM-EDS, BET surface area measurement and X-ray diffraction (XRD).

  • 30. Lindström, B.
    et al.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Hydrogen generation by steam reforming of methanol over copper-based catalysts for fuel cell applications2001In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 26, no 9, p. 923-933Article in journal (Refereed)
    Abstract [en]

    This paper presents an investigation concerning the reforming of methanol over various base-metal oxide catalysts. Copper-based catalysts were effective for the steam reforming of methanol. The selectivity and conversion was studied in a flow reactor in the temperature interval 180-320 degreesC. The active materials were impregnated on gamma -alumina pellets using the wet impregnation method. The promoters used in the investigation were chromium (Cr), zinc (Zn) and zirconia (Zr). The copper content and promoter used played an important role in the catalyst's ability to selectively convert methanol at low temperatures. Catalysts with high copper contents generally gave higher conversions and selectivities for the steam reforming reaction. The use of ternary components generally increased the catalyst selectivity towards carbon dioxide. Zirconia had a positive influence on the catalytic performance at low temperatures. The possibilities for the use of reforming systems with copper-based catalysts in fuel cell applications are promising.

  • 31. Lindström, B.
    et al.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Steam reforming of methanol over copper-based monoliths: the effects of zirconia doping2002In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 106, no 02-jan, p. 264-273Article in journal (Refereed)
    Abstract [en]

    In this paper, an experimental investigation concerning steam reforming of methanol over various alumina-supported monolithic copper-based catalysts is presented. The activity and carbon dioxide selectivity was studied over two sets of catalysts, one of which was doped with zirconium, with five different copper contents. The zirconium-doped catalyst were less active with respect to the hydrogen yield, however, they were at all times more selective towards carbon dioxide over the entire temperature interval. The catalysts have been characterised using Brunauer-Emmett-Teller (BET) surface area measurement and X-ray diffraction (XRD). The results show that the copper loading and modification of the active material by zirconia doping had a great influence on the methanol conversion and carbon dioxide selectivity of the steam reforming reaction.

  • 32. Lindström, B.
    et al.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Menon, P. G.
    Activity and characterization of Cu/Zn, Cu/Cr and Cu/Zr on gamma-alumina for methanol reforming for fuel cell vehicles2002In: Applied Catalysis A: General, ISSN 0926-860X, E-ISSN 1873-3875, Vol. 234, no 02-jan, p. 111-125Article in journal (Refereed)
    Abstract [en]

    The influence of catalyst properties on the activity and selectivity of hydrogen generation by methanol reforming over copper-based catalysts impregnated on gamma-alumina pellets has been investigated. In the experiments, three sets of copper-based catalysts with various compositions were tested: Cu/Zn/Al2O3, Cu/Cr/Al2O3 and Cu/Zr/Al2O3. The catalysts were characterized using temperature programmed reduction (TPR), temperature programmed oxidation (TPO), SEM-EDS, Brunauer-Emmett-Teller (BET) surface area measurement and X-ray diffraction (XRD). The copper surface area was determined by pulse chemisorption using N2O. We found a correlation between the copper surface area and catalytic activity. The activity tests were performed in a fixed bed reactor with 15 g of spherical catalyst pellets using a gas hourly space velocity (GHSV) of 25,000. The results of the activity tests indicate that the choice of promoter and the catalyst composition greatly influence the activity as well as the selectivity for CO2 formation. The highest conversions were achieved for the zinc-containing catalysts (Cu/Zn/Al2O3) for both steam reforming and the combined reforming process. Complete conversion of methanol was only obtained for the zinc-containing catalysts when running the steam reforming process. The combined reforming process generally yielded A product stream containing lower carbon monoxide concentrations compared to steam reforming at the equivalent reactor temperature for all of the catalysts tested.

  • 33.
    Lindström, Bård
    et al.
    Powercell Sweden AB.
    Pettersson, Lars J
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Lundgren, Staffan
    Volvo Technology AB.
    REFORMER REACTOR AND METHOD FOR CONVERTING HYDROCARBON FUELS INTO HYROGEN RICH GAS2014Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    A reformer reactor is provided for converting hydrocarbon fuel into hydrogen rich gas by auto-thermal reaction process. The reformer reactor has a preferably cylindrically shaped, double wall housing with an inner wall and an outer wall and two side faces, wherein the inner wall and the two side faces form a  reaction  chamber. Additionally,  the inner wall is charged with a first electric charge which prevents the hydrocarbon fuel molecules injected into the reaction chamber by a fuel inlet from hitting the warm inside surfaces of the reaction chamber and burn to soot, subsequently.

  • 34.
    Moud, Pouya H.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Granestrand, Jonas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Dahlin, Sandra
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Nilsson, Marita
    Scania CV AB, Mat Technol Engine Performance & Emiss, Sodertalje, Sweden..
    Andersson, Klas
    Haldor Topsoe Res Labs, Lyngby, Denmark..
    Pettersson, Lars J.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Engvall, Klas
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Process Technology.
    Role of alkali in heterogeneous catalysis for gas cleaning in stationary and mobile applications2015In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Article in journal (Other academic)
  • 35.
    Musavi, Zahra S.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Engvall, Klas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Modeling, Design, and Verification of a Burner for Partial Oxidation of Biomass Product Gas in an Autothermal Reformer2016In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 55, no 36, p. 9687-9697Article in journal (Refereed)
    Abstract [en]

    There is global interest in utilization of biomass energy through thermochemical processes such as gasification. The crucial step in many gasification processes is the upgrading of the produced gas, removing for example problematic components, such as tar, preferably with a flexible solution that adapts to several feedstock compositions, gasification technologies, and conditions. The present work focuses on the underpinning modeling for the development of a burner for partial combustion in an autothermal tar reformer. A design and modeling study considering the effect of the burner geometry and inlet locations on flame stability was performed. The model and the constructed burner is verified and validated against experimental results, displaying a successful operation of the combustion zone, verifying and validating the developed model against specific requirements. The verified model was finally applied for an extended process window.

  • 36.
    Nilsson, Marita
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Dawody, Jazaer
    Lindström, Bård
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Effect of Mn addition to CeO2-ZrO2-supported Rh and Ru catalysts on the activity for diesel reformingIn: Catalysis Letters, ISSN 1011-372X, E-ISSN 1572-879XArticle in journal (Other academic)
  • 37.
    Nilsson, Marita
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Jansson, Kjell
    Jozsa, Peter
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Catalytic properties of Pd supported on ZnO/ZnAl2O4/Al2O3 mixtures in dimethyl ether autothermal reforming2009In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 86, p. 18-26Article in journal (Refereed)
    Abstract [en]

    The catalytic properties of Pd supported on mixtures of zinc oxide, zinc aluminate, and alumina, prepared from gamma-alumina and zinc nitrate, were studied for autothermal reforming (ATR) of dimethyl ether (DME). The performance of the catalysts was tested in a small-scale reactor, using cordierite monoliths as substrate. The catalysts exhibited high activity and generated hydrogen-rich product gases with CO concentrations below 5 vol.% in the temperature range between 350 and 450 degrees C (at O-2:DME = 0.7, H2O:DME = 2.5, and GHSV = 15000 h(-1)). The highest DME conversion was obtained for a catalyst in which the support comprised mainly ZnAl2O4. Physical mixing of the catalysts with gamma-Al2O3 resulted in increased DME conversion but a lowering of the CO2 selectivity.The catalysts were characterized by CO chemisorption, liquid nitrogen adsorption, temperature-programmed desorption of ammonia, temperature-programmed reduction, transmission electron microscopy, and X-ray diffraction. It was found that decreasing surface area and decreasing number of acid sites, caused by thermal treatment during generation of the supports, did not affect the activity negatively. The high CO2 selectivity of the catalysts was correlated with PdZn alloy formation.

  • 38.
    Nilsson, Marita
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Jozsa, Peter
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Evaluation of Pd-based catalysts and the influence of operating conditions for autothermal reforming of dimethyl ether2007In: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 76, p. 41-49Article in journal (Refereed)
    Abstract [en]

    A series of different Pd-based catalysts supported on ceramic monoliths were synthesized and tested in a screening study for autothermal reforming of dimethyl ether (DME). Alumina-supported Pd was shown to be very active for this reaction at temperatures between 350 and 400 degrees C. Adding Zn to Pd/gamma-Al2O3 decreased the activity of decomposition reactions leading to better reforming activity, and resulting in high selectivity to carbon dioxide. Pd-Zn/gamma-Al2O3 was further evaluated in a parameter study varying oxygen-to-DME ratio, steam-to-DME ratio and temperature. The effect on the reformer performance of changing the operating conditions is discussed. The Pd-Zn/gamma-Al2O3 catalyst generated carbon monoxide concentrations below 5%, and hydrogen concentrations close to 50%. The catalyst performance was significantly improved by preconditioning in hydrogen. Results from a first round of catalyst characterization studies suggest that Pd-Zn species are formed on the alumina support following reduction

  • 39.
    Nilsson, Marita
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Karatzas, Xanthias
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Lindström, Bård
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Assessing the adaptability to varying fuel supply of an autothermal reformer2008In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 142, p. 309-317Article in journal (Refereed)
    Abstract [en]

    The present paper describes the study of an autothermal reformer and its fuel-flexible capabilities. Experiments have been performed in a reactor designed to generate hydrogen by autothermal reforming for a 1-5 kW(e) polymer electrolyte fuel cell. Both logistic fuels (diesel, gasoline, and E85) and alternative fuel candidates (methanol, ethanol, and dimethyl ether) were tested in the reformer. The same catalyst composition, Rh supported on Ce/La-doped gamma-Al2O3 and deposited on cordierite monoliths, was used for all fuels. The practical feasibility of reforming each fuel in the present reactor design was tested and evaluated in terms of fuel conversion and selectivity to hydrogen and carbon dioxide. Temperature profiles were studied both in the axial and radial direction of the reformer. It was concluded from the experiments that the reformer design was most suitable for use with hydrocarbon mixtures Such as diesel, gasoline, and E85, where it represents a good basis for an optimized multifuel-reformer design.

  • 40.
    Nilsson, Marita
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Karlsson, Anders
    Lindström, Bård
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Study of a reactor concept for hydrogen generation from diesel fuelIn: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045Article in journal (Other academic)
  • 41.
    Nilsson, Marita
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Lindström, Bard
    Hydrogen generation from dimethyl ether for fuel cell auxiliary power units2006In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 20, no 5, p. 2164-2169Article in journal (Refereed)
    Abstract [en]

    Copper-based catalysts have been evaluated for the combined partial oxidation and steam reforming of dimethyl ether (DME) in a reformer designed to produce hydrogen for a full-scale heavy-duty truck auxiliary power unit. The experiments were conducted using gas mixtures similar to realistic operating conditions. A Pd-promoted CuZn catalyst was found to be highly selective for hydrogen production from DME at O-2/DME = 0.25 and H2O/ DME = 2.5. The catalysts were characterized using Brunauer-Emmett-Teller surface area measurement, X-ray diffraction, and temperature-programmed reduction. The copper surface area was determined by pulse chemisorption of nitrous oxide. In addition to the reforming catalyst evaluation, a startup sequence was tested, where DME was catalytically ignited and combusted over platinum or iron oxide catalysts.

  • 42.
    Persson, Henry
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Duman, Isa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Wang, Shule
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Pettersson, Lars
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Catalytic pyrolysis over transition metal-modified zeolites: a comparative study between catalyst activity and deactivation2019In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 138, p. 54-61Article in journal (Refereed)
    Abstract [en]

    The utilization of metal-doped zeolites in catalytic pyrolysis of biomass is a well-known approach to promote the formation of certain compounds. One major technical issue of using zeolites in biomass pyrolysis processes is their rapid deactivation due to coke formation. However, little is known about how metal-doping influences the characteristics of coking, such as coking rate and its composition.

    In this study, four different materials were experimentally evaluated based on their catalytic activity and coking characteristics: HZSM-5, Fe/ZSM-5, Ni/ZSM-5 and FeNi/ZSM-5. The materials were prepared and characterized followed by screening in a bench-scale setup for in-situ catalytic pyrolysis. The mass balance and composition of pyrolysis products including catalyst coke were analyzed.

    It was found that metal-doping increases the concentration of aromatic hydrocarbons in the liquid product from 59.0 to 82.8 % of GC/MS peak area, especially monoaromatic hydrocarbons (MAHs) and naphthalenes. Fe mainly promotes MAHs whereas Ni additionally promotes naphthalenes. FeNi/ZSM-5 enhances the production of both compound groups as well as further reducing the total acid number (TAN). Regarding the catalyst coke, metal-doped catalysts present an increased concentration of aromatic hydrocarbons in terms of MAHs, naphthalenes and polyaromatic hydrocarbons. For each catalyst, the chemical composition of catalyst coke reflects the catalyst’s activity seen in vapor upgrading. A reaction pathway based on the observed catalyst activities of metal-doped ZSM-5 and HZSM-5 is proposed.

    The results also show that metal-doping of catalysts increases the formation of catalyst coke, mainly due to a higher concentration of strong acid sites. Also, the rate of coking is dependent on the strength of acid sites, where the strength correlates with the severity of coking. The coke yield was seen to increase from 3.5 wt% in the case of HZSM-5 to maximum 7.2 wt% over Fe/ZSM-5. However, the metal-doping of catalysts reduces the temperature of catalyst regeneration and catalyzes the oxidation of coke. Overall, this work presents a comparative study between catalyst activity and deactivation during thermochemical conversion of biomass.

  • 43. Persson, K.
    et al.
    Thevenin, P. O.
    Jansson, K.
    Agrell, J.
    Järås, Sven G.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Preparation of alumina-supported palladium catalysts for complete oxidation of methane2003In: Applied Catalysis A: General, ISSN 0926-860X, E-ISSN 1873-3875, Vol. 249, no 1, p. 165-174Article in journal (Refereed)
    Abstract [en]

    Alumina-supported palladium catalysts (Pd/Al2O3) have been prepared by incipient wetness (IW), grafting (G) and microemulsion techniques (ME). Two slightly different microemulsion methods have been used (ME1) and (ME2). The catalysts have been calcined at 1000 degreesC for 4 h. The catalysts have then been examined with respect to their activity for the combustion of methane, during heating and cooling ramps. Pd/Al2O3-IW and Pd/Al2O3-ME2 exhibit the highest activity whereas Pd/Al2O3-ME1 and Pd/Al2O3-G are the less active. There is not much of a difference in activity between Pd/Al2O3-IW and Pd/Al2O3-ME2, despite strong differences in palladium particle size observed by TEM analysis. TPO experiments show that Pd/Al2O3-IW and Pd/Al2O3-ME2 present a higher PdO/Pd ratio than the other samples exhibit. The preparation technique affects the reoxidation ability of palladium during cooling, hence the combustion activity of the fresh catalyst, as PdO is more active than Pd for the complete oxidation of methane under lean conditions.

  • 44.
    Petersson, Lars
    KTH, Superseded Departments, Numerical Analysis and Computer Science, NADA.
    A framework for integration of processes in autonomous systems2002Doctoral thesis, monograph (Other scientific)
  • 45.
    Pettersson, Lars J.
    et al.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Westerholm, R.
    State of the art of multi-fuel reformers for fuel cell vehicles: problem identification and research needs2001In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 26, no 3, p. 243-264Article, review/survey (Refereed)
    Abstract [en]

    This review is focused on discussions about multi-fuel reformer technology for fuel cell vehicles where techniques for onboard hydrogen generation and gas clean-up processes, as well as full considerations and emissions are included. Our conclusion is that the potential for developing a highly efficient, durable and reliable reformer system fur automotive applications is considerably higher if dedicated fuel reformers are used instead of applications where all types of fuels ranging from natural gas to heavy diesel fuels can be used. The authors propose that petroleum-derived fuels should be designed for potential use in mobile fuel cell applications. The present literature review together with site visit discussions has led to the conclusion that there are relatively low emissions from fuel cell engines compared to internal combustion engines. However, the major research work on reformers-fuel cells have been performed during steady-state operation. Emissions during start-up, shutdown and transient operation are basically unknown and must be investigated in more detail.

  • 46. Pocoroba, E.
    et al.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Agrell, J.
    Boutonnet, Magali
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Jansson, K.
    Exhaust gas catalysts for heavy-duty applications: influence of the Pd particle size and particle size distribution on the combustion of natural gas and biogas2001In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 16, no 04-jan, p. 407-412Article in journal (Refereed)
    Abstract [en]

    In this study, an experimental investigation concerning exhaust gas catalysts for heavy-duty diesel engines fuelled by natural gas or biogas is presented. Miniature monoliths, 2.5 wt% Pd/Al2O3, have been prepared, characterised and tested. Various methods have been used in order to obtain different palladium particle sizes, including incipient wetness and microemulsion technique. Crystallite sizes between 2 and 40 nm were obtained. We observed that the metal particle size influences the activity for methane oxidation. Moreover, the homogeneity of the active material was found to affect the reaction rate.

  • 47.
    Sebelius, Sara
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Le, Tan Thanh
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Pettersson, Lars J.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Lind, Hanna
    Identification of urea decomposition from an SCR perspective: A combination of experimental work and molecular modeling2013In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 231, p. 220-226Article in journal (Refereed)
    Abstract [en]

    For the automotive industry selective catalytic reduction (SCR) is the most effective way to get rid of poisonous nitrogen oxides (NOX) in the exhaust. Urea is used as precursor for the reducing agent ammonia. The stricter legislation on NOX emissions for heavy duty vehicles in Euro 6 makes it even more important to optimize the conversion of urea to ammonia.Competing with ammonia formation is the formation of two byproducts commonly observed in the SCR system, biuret and cyanuric acid. These byproducts are formed before the SCR catalyst in the trucks. In the literature different possibilities on the reaction pathway to biuret and cyanuric acid are described. The aim of this study is to understand which of these pathways that is more likely to occur.In this study, the decomposition and synthesis pathways from urea to biuret and cyanuric acid were identified by a combination of laboratory experiments and Density Functional Theory (DFT) calculations. This is the first DFT study on these reactions performed without the influence of a catalyst. Accordingly, this is a study of the reactions where they do occur, before and not over the catalyst. A new gas phase FTIR method for urea and its byproducts was developed.

  • 48. Thevenin, P. O.
    et al.
    Alcalde, A.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Järås, Sven G.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Fierro, J. L. G.
    Catalytic combustion of methane over cerium-doped palladium catalysts2003In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 215, no 1, p. 78-86Article in journal (Refereed)
    Abstract [en]

    Various Pd-supported catalysts have been prepared using three different types of alumina as support material: (a) gamma-alumina, (b) Ba-stabilized alumina, and

  • 49. Thevenin, P. O.
    et al.
    Pocoroba, E.
    Pettersson, Lars J.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Karhu, H.
    Vayrynen, I. J.
    Järås, Sven G.
    KTH, Superseded Departments, Chemical Engineering and Technology.
    Characterization and activity of supported palladium combustion catalysts2002In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 207, no 1, p. 139-149Article in journal (Refereed)
    Abstract [en]

    The catalytic activity of Pd supported on gamma-Al2O3, Ba-Al2O3, and La-Al2O3 has been examined in complete oxidation of methane when operating in excess of oxygen. Two different sizes of I'd particles have been considered. Foreign ions have a strong influence with respect to the stabilization of alumina when submitted to a temperature as high as 1000 degrees C. In contrast, no specific effect can be detected when the samples are calcined at 500 degreesC. Interaction with the supported palladium particles, observed during the combustion reaction, has been investigated by X-ray photoelectron Spectroscopy and temperature-programmed oxidation. The difference in combustion activity is attributed to the difference in surface oxidation states of the Pd particles. The presence of foreign ions in the alumina structure results in surface PdO only. When supported on gamma-Al2O3, small amounts of metallic Pd can be detected, resulting in a lower ignition temperature.

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