Papers by Christian Hulteberg
Journal of Loss Prevention in the Process Industries
Topics in Catalysis, Jan 18, 2023
Active sites in Mo-based hydrotreating catalysts are produced by sulfidation. To achieve insights... more Active sites in Mo-based hydrotreating catalysts are produced by sulfidation. To achieve insights that may enable optimization of the catalysts, this process should be studied in situ. Herein we present a comparative XAFS study where the in situ sulfidation of Mo/δ-Al 2 O 3 and Ni/δ-Al 2 O 3 is compared to that of δ-Al 2 O 3 supported NiMo catalysts with different NiMo ratios. The study also covers the comparison of sulfidation of Ni and Mo using different oxide supports as well as the sulfidation conditions applied in the reactor. The XAFS spectra confirms the oxide phase for all catalysts at the beginning of the sulfidation reaction and their conversion to a sulfidized phase is followed with in situ measurements. Furthermore, it is found that the monometallic catalysts are less readily sulfidized than bimetallic ones, indicating the importance of Ni-Mo interactions for catalyst activation. Mo K-edge XAFS spectra did not show any difference related to the support of the catalyst or the pressure applied during the reaction. Ni K-edge XAFS spectra, however, show a more complete sulfidation of the Ni species in the catalyst when SiO 2 is used as a support as compared to the Al 2 O 3. Nevertheless, it is believed that stronger interactions with Al 2 O 3 support prevent sintering of the catalyst which leads to its stabilization. The results contribute to a better understanding of how different parameters affect the formation of the active phase of the NiMo catalysts used in the production of biofuel.
Catalysts
Nickel (Ni)-promoted Molybdenum (Mo)-based catalysts are used for hydrotreatment processes in the... more Nickel (Ni)-promoted Molybdenum (Mo)-based catalysts are used for hydrotreatment processes in the chemical industry where the catalysts are exposed to high-pressure H2 at elevated temperature. In this environment, the catalyst transforms into the active phase, which involves the reduction of the oxide. Here, we report on the first in situ study on the reduction of alumina supported Ni- and Mo-based catalysts in 1 mbar H2 using ambient-pressure X-ray photoelectron spectroscopy (APXPS). The study confirms that mixing Ni and Mo lowers the reduction temperature of both Ni- and Mo-oxide as compared to the monometallic catalysts and shows that the MoO3 reduction starts at a lower temperature than the reduction of NiO in NiMo/Al2O3 catalysts. Additionally, the reduction of Ni and Mo foil was directly compared to the reduction of the Al2O3-supported catalysts and it was observed that the reduction of the supported catalysts is more gradual than the reduction of the foils, indicating a stron...
32nd International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2019, 2019
Co-feeding of renewable feedstocks in general, and lignin streams in particular, in petroleum ref... more Co-feeding of renewable feedstocks in general, and lignin streams in particular, in petroleum refineries is an attractive means of increasing the proportion of renewable fuel. Four separate units in an integrated refinery can be envisioned using lignin as a feedstock: the hydrotreater, the fluidised catalytic cracker, the hydrocracker and the slurry hydrotreater. A conceptual process design study, including cost assessments, is presented on the possibility of co-feeding lignin in one of these stages in a conventional crude oil refinery. The addition of lignin to an existing diesel hydrotreating unit is investigated in a refinery environment. Rigorous process simulation models were developed for such an integrated lignin-petroleum refinery based on real data. The lignin product shows good potential of ending up in the gasoline pool with about one third having a boiling point within the gasoline range, one third in the diesel range and the final third ending up in the LPG and kerosene pools. The total production cost of gasoline from lignin is estimated to be 0.82 €/L. If all or most tax reductions on fuels from sustainable sources could be utilised, lignin would be a viable resource for the production of biomass-based gasoline
Biotechnology for Biofuels, 2019
ACS Sustainable Chemistry & Engineering, 2021
Industrial lignin such as kraft lignin is an abundant feedstock for renewable chemicals and mater... more Industrial lignin such as kraft lignin is an abundant feedstock for renewable chemicals and materials. In this study, a process was developed for depolymerization of kraft lignin followed by an upgrading separation step and further bioconversion of the obtained monoaromatic compounds to muconic acid. First, industrial kraft lignin, Indulin AT, was processed into a guaiacolrich stream using base-catalyzed depolymerization. This stream was subsequently upgraded using liquid−liquid extraction and evaporation to yield a more concentrated and less inhibitory stream, adapted for bioconversion. Finally, guaiacol was quantitatively converted to muconic acid through bioconversion using an engineered Pseudomonas putida strain containing cytochrome P450 and ferredoxin reductase for guaiacol assimilation and deletion of the native catBC genes for muconic acid production. Isomerization of muconic acid in a fermentation medium depending on pH was also studied.
The present invention describes a method for the treatment of tall oil pitch (TOP), said method c... more The present invention describes a method for the treatment of tall oil pitch (TOP), said method comprising heating the TOP and optionally additives including water and steam to a temperature of at least 300°C; maintaining the temperature in the reactor at 300°C or higher for a period of time to enable thermal treatment of the TOP to act on components thereof toproduce fatty acids and/or rosin acids, and/or derivatives thereof,and/or unsaponifiables and/or derivatives having lower molecular weight compared to the high molecular weight components with molecular weights of at least 350 g/mole present in the original TOP, to yield a modified TOP material with lower viscosity
It is not easy to replace fossil-based fuels in the transport sector, however, an appealing solut... more It is not easy to replace fossil-based fuels in the transport sector, however, an appealing solution is to use biomass and waste for the production of renewable alternatives. Thermochemical conversion of biomass for production of synthetic transport fuels by the use of gasification is a promising way to meet these goals. One of the key challenges in using gasification systems with biomass and waste as feedstock is the upgrading of the raw gas produced in the gasifier. These materials replacing oil and coal contain large amounts of demanding impurities, such as alkali, inorganic compounds, sulphur and chlorine compounds. Therefore, as for all multi-step processes, the heat management and hence the total efficiency depend on the different clean-up units. Unfortunately, the available conventional gas filtering units for removing particulates and impurities, and also subsequent catalytic conversion steps have lower optimum working temperatures than the operating temperature in the gasification units. This report focuses on ongoing research and development to find new technology solutions and on the key critical technology challenges concerning the purification and upgrading of the raw gas to synthesis gas and the subsequent different fuel synthesis processes, such as hot gas filtration, clever heating solutions and a higher degree of process integration as well as catalysts more resistant towards deactivation. This means that the temperature should be as high as possible for any particular upgrading unit in the refining system. Nevertheless, the temperature and pressure of the cleaned synthesis gas must meet the requirements of the downstream application, i.e. Fischer-Tropsch diesel or methanol. Before using the gas produced in the gasifier a number of impurities needs to be removed. These include particles, tars, sulphur and ammonia. Particles are formed in gasification, irrespective of the type of gasifier design used. A first, coarse separation is performed in one or several cyclone filters at high temperature. Thereafter bag-house filters (e.g. ceramic or textile) maybe used to separate the finer particles. A problem is, however, tar condensation in the filters and there is much work performed on trying to achieve filtration at as high a temperature as possible. The far most stressed technical barriers regarding cleaning of the gases are tars. To remove the tar from the product gas there is a number of alternatives, but most important is that the gasifier is operated at optimal conditions for minimising initial tar formation. In fluid bed and entrained flow gasification a first step may be catalytic tar cracking after particle removal. In fluid bed gasification a catalyst, active in tar cracking, may be added to the fluidising bed to further remove any tar formed in the bed. In this kind of tar removal, natural minerals such as dolomite and olivine, are normally used, or catalysts normally used in hydrocarbon reforming or cracking. The tar can be reformed to CO and hydrogen by thermal reforming as well, when the temperature is increased to 1300ºC and the tar decomposes. Another method for removing tar from the gas is to scrub it by using hot oil (200-300ºC). The tar dissolves in the hot oil, which can be partly regenerated and the remaining tar-containing part is either burned or sent back to the gasifier for regasification. Other important aspects are that the sulphur content of the gas depends on the type of biomass used, the gasification agent used etc., but a level at or above 100 ppm is not unusual. Sulphur levels this high are not acceptable if there are catalytic processes downstream , or if the emissions of e.g. SO2 are to be kept down. The sulphur may be separated by adsorbing it in ZnO, an irreversible process, or a commercially available reversible adsorbent can be used. There is also the possibility of scrubbing the gas with an amine solution. If a reversible alternative is chosen, elementary sulphur may be produced using the Claus process. Furthermore, the levels of ammonia formed in gasification (3,000 ppm is not uncommon) are normally not considered a problem. When combusting the gas, nitrogen or in the worst case NOx (so-called fuel NOx) is formed; there are, however, indications that there could be problems. Especially when the gasification is followed by downstream catalytic processes, steam reforming in particular, where the catalyst might suffer from deactivation by long-term exposure to ammonia. The composition of the product gas depends very much on the gasification technology, the gasifying agent and the biomass feedstock. Of particular significance is the choice of gasifying agent, i.e. air, oxygen, water, since it has a huge impact on the composition and quality of the gas, The gasifying agent also affects the choice of cleaning and upgrading processes to syngas and its suitability for different end-use applications as fuels or green chemicals. The ideal upgraded syngas consists of H2 and CO at a correct ratio with very low water and CO2 content allowed. This means that the tars, particulates, alkali salts and inorganic compounds mentioned earlier have to be removed for most of the applications. By using oxygen as the gasifying agent, instead of air, the content of nitrogen may be minimised without expensive nitrogen separation.
This project is financed and carried out within the f3 and Swedish Energy Agency collaborative re... more This project is financed and carried out within the f3 and Swedish Energy Agency collaborative research program Renewable transportation fuels and systems (Förnybara drivmedel och system). f3 Swedish Knowledge Centre for Renewable Transportation Fuels is a networking organization which focuses on development of environmentally, economically and socially sustainable renewable fuels, and Provides a broad, scientifically based and trustworthy source of knowledge for industry, governments and public authorities Carries through system oriented research related to the entire renewable fuels value chain Acts as national platform stimulating interaction nationally and internationally. f3 partners include Sweden's most active universities and research institutes within the field, as well as a broad range of industry companies with high relevance. f3 has no political agenda and does not conduct lobbying activities for specific fuels or systems, nor for the f3 partners' respective areas of interest. The f3 centre is financed jointly by the centre partners and the region of Västra Götaland. f3 also receives funding from Vinnova (Sweden's innovation agency) as a Swedish advocacy platform towards Horizon 2020. Chalmers Industriteknik (CIT) functions as the host of the f3 organization (see www.f3centre.se). The project has been a collaboration between six f3 partners including both universities and companies as follows: Lund University, Environmental and Energy Systems Studies (Pål Börjesson,
Additional file 1: Figure S1. (a) The SEC chromatogram of 1 g/L depolymerized (at 220 °C, 5 mL/mi... more Additional file 1: Figure S1. (a) The SEC chromatogram of 1 g/L depolymerized (at 220 °C, 5 mL/min) lignin. Red-dotted lines represent the fractions collected. The collected fraction at 95–108 minutes corresponds to the 0.2–0.4 kDa peak in the SEC chromatograms calibrated with PEG standards. (b) UHPLC chromatograms of the fractions obtained from SEC. The peaks in the fraction 95–108 minutes correspond to aromatic monomers (Vanillin-3.5 min; guaiacol-4.6 min; acetovanillone-4.7 min). Table S1. Results of homology BLAST with the previously well-characterized DyP proteins against the genome of the organisms used in this study. P. putida EM42 strain used in this study is the modified version of KT2440 and hence, the genome of KT2440 (parental strain) was used for BLAST searches. Proteins with identity more than 75 % are emphasized in green. Proteins that were found absent and the ones with less than 30 % query are highlighted in red. P. fluorescens highlighted in blue is the only organi...
Topics in Catalysis, 2017
Preface : Special issue of Topics in Catalysis constitutes the Proceedings of the 17th Nordic Sym... more Preface : Special issue of Topics in Catalysis constitutes the Proceedings of the 17th Nordic Symposium of Catalysis
Through the 20th century the use of glycerine has mainly been focused to the food industry, the c... more Through the 20th century the use of glycerine has mainly been focused to the food industry, the cosmetic industry and the pharmaceutical industry. The required volumes for these industries can’t be compared with the larger bulk chemicals produced today. These low requirements together with the increased glycerine production, associated with the biodiesel production from which glycerine is a large by-product, has forced the prices down to approximately 100-150 $/tonne. This low cost crude glycerine has been an initiator for developing methods on how to convert the glycerine to more usable products. A proposed method by the company Biofuel Solutions has been to convert the glycerine into bio-LPG. With the EU directives stating that at least 10 % of the fuels in the transport sector should come from renewable sources this route may turn out favourable. This will though cause a large increase in demand as one of the few new ways to provide bio-LPG and thus increase in price, which will ...
Performing fundamental operando catalysis studies under realistic conditions is a key to further ... more Performing fundamental operando catalysis studies under realistic conditions is a key to further develop and increase the efficiency of industrial catalysts. Operando X-ray photoelectron spectroscopy (XPS) experiments have been limited to pressures, and the relevance for industrial applications has been questioned. Herein, we report on the CO oxidation experiment on Pd(100) performed at a total pressure of 1 bar using XPS. We investigate the light-off regime and the surface chemical composition at the atomistic level in the highly active phase. Furthermore, the observed gas-phase photoemission peaks of CO 2 , CO, and O 2 indicate that the kinetics of the reaction during the light-off regime can be followed operando, and by studying the reaction rate of the reaction, the activation energy is calculated. The reaction was preceded by an in situ oxidation study in 7% O 2 in He and a total pressure of 70 mbar to confirm the surface sensitivity and assignment of the oxygen-induced photoemission peaks. However, oxygen-induced photoemission peaks were not observed during the reaction studies, but instead, a metallic Pd phase is present in the highly active regime under the conditions applied. The novel XPS setup utilizes hard X-rays to enable high-pressure studies, combined with a grazing incident angle to increase the surface sensitivity of the measurement. Our findings demonstrate the possibilities of achieving chemical information of the catalyst, operando, on an atomistic level, under industrially relevant conditions.
ChemSusChem, 2020
Abstract Lignin is a polyaromatic polymer contained in plant cell walls, and it is considered the... more Abstract Lignin is a polyaromatic polymer contained in plant cell walls, and it is considered the most abundant noncarbohydrate polymer on Earth. The aromaticity and richness of its functional groups render lignin an attractive starting biomacromolecule for conversion into a variety of value‐added products. The development of successful strategies for lignin valorization infers the design of effective depolymerization protocols. Most research on lignin depolymerization has focused on batch‐mode processing, whereas only a few studies have investigated such lignin transformations in continuous reactor systems. In this Concept, emerging developments within the concept of continuous lignin processing and the challenges remaining in realizing the efficient valorization of lignin by using this technology are highlighted. A special focus is set on the hydrothermal conversion of technical lignin under continuous‐flow conditions, together with suggestions for future research and technology development.
Journal of Colloid and Interface Science, 2019
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Papers by Christian Hulteberg