Atte Aho

Pyrolysis of Softwood Carbohydrates in a Fluidized Bed Reactor

In the present work pyrolysis of pure pine wood and softwood carbohydrates, namely cellulose and galactoglucomannan (the major hemicellulose in coniferous wood), was conducted in a batch mode operated fluidized bed reactor. Temperature ramping (5 °C/min) was applied to the heating until a reactor temperature of 460 °C was reached. Thereafter the temperature was kept until the release of non-condensable gases stopped. The different raw materials gave significantly different bio-oils. Levoglucosan was the dominant product in the cellulose pyrolysis oil. Acetic acid was found in the highest concentrations in both the galactoglucomannan and in the pine wood pyrolysis oils. Acetic acid is most likely formed by removal of O-acetyl groups from mannose units present in GGM structure.

Pyrolysis of pine and gasification of pine chars - influence of organically bound metals.

Pyrolysis of pine and gasification of pine chars was studied in this work, focusing on the influence of organically bound metals. Selective leaching of the major ash-forming elements in pine wood was performed with different acids, namely, nitric, sulfuric, hydrochloric and oxalic acids. No other major changes in the chemical composition of the biomass were observed except the removal of the metals. The effect of organically bound sodium, potassium, magnesium and calcium was studied in both pyrolysis and gasification. Removal of the metals had a positive effect on the pyrolysis, resulting in higher bio-oil, lower char and gas yields.

Isomerization of α-Pinene Oxide Over Iron-Modified Zeolites

Fe-modified mordenite, ferrierite, Y, ZSM-5, ZSM-12 and beta zeolite catalysts were prepared by solid state ion-exchange and conventional liquid phase ion-exchange methods from aqueous solutions. Sn- modified H-beta-300 zeolite catalyst was prepared by the later method. The characterization of proton form, Fe and Sn modified zeolites was carried out using X-ray powder diffraction, scanning electron microscopy, Mössbauer spectroscopy with magnetic measurements, transmission electron microscopy, nitrogen adsorption, X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma spectroscopy, thermo-gravimetric analysis and FTIR spectroscopy using pyridine as a probe molecule. Isomerization of α-pinene oxide over the Fe and Sn modified zeolite catalysts was carried out in the liquid phase using a batch-wise glass reactor. Formation of campholenic aldehyde and fencholenic aldehyde were observed to be influenced by the structure, acidity of zeolite and contents of Fe and Sn, reaction temperature and the catalysts pretreatment.

Zeolite-bentonite hybrid catalysts for the pyrolysis of woody biomass

Hybrid catalysts consisting of a zeolite (ZSM-5 or Beta) and bentonite as a binder were prepared and characterized by XRD, pyridine FTIR and nitrogen adsorption. The hybrid catalysts exhibited similar properties as the combined starting materials. Catalytic pyrolysis over pure ZSM-5 and Beta as well as hybrid catalysts has been successfully carried out in a dual-fluidized bed reactor. De-oxygenation of the produced bio-oil over the different zeolitic materials was increased compared to non-catalytic pyrolysis over quartz sand.

Catalytic pyrolysis of woody biomass

A review of the literature published between 2006 and 2009 concerning the pyrolysis of woody biomass and the catalytic upgrading of bio-oil is presented. The main results of our group regarding catalytic pyrolysis of woody biomass are also overviewed. Three different methods for investigating the effect of catalysts on the catalytic pyrolysis of woody biomass were investigated. The first method was conventional thermogravimetry, but, due to the lack of gas analysis, valuable information could not be obtained by this method. The second method of investigation was simultaneous pyrolysis and upgrading over zeolites in a fluidized bed reactor. In the third method, the pyrolysis occurred in a fluidized bed reactor and the pyrolysis vapors were upgraded downstream over zeolites in another fluidized bed reactor. For laboratory-scale pyrolysis, this method was the most suitable for screening of different zeolite catalysts, which was the main objective. It was possible to deoxygenate the bio-oil over zeolites in both fluidized bed reactor set-ups, resulting in higher CO and water formation.

Catalytic Pyrolysis of Lignocellulosic Biomass

Pyrolysis of lignocellulosic biomass produces liquid, solid, and gaseous products. The liquid, called bio-oil, can be used as a fuel in stationary power plants. In order to use it in mobile applications, it has to be catalytically upgraded. Such upgrading can be performed in different ways, namely, by catalytic pyrolysis using zeolites or mesoporous materials, hydrodeoxygenation, and aqueous and steam reforming, as well as reactive distillation. This review focuses on the catalytic pyrolysis over zeolites and mesoporous materials. The major chemical components in lignocellulosic biomass are presented and the reaction conditions for maximizing the bio-oil yield are explained. Furthermore, the influence of different properties of zeolites and mesoporous materials, namely, acidity, pore size, and metal modification, on the upgrading activity is reviewed.

Green catalysis by nanoparticulate catalysts developed for flow processing? Case study of glucose hydrogenation

Heterogeneous catalysis, flow chemistry, continuous processing, green solvents, catalyst immobilization and recycling are some of the most relevant, emerging key technologies to achieve green synthesis. However, a quantification of potential effects on a case to case level is required to provide a profound answer, whether they can lead to a superior process compared to the industrial standard. To do so, holistic environmental assessment approaches are very useful tools providing insights and decision support during the process development phase. Herein, novel heterogeneous nanoparticulate ruthenium catalysts immobilized on hyperbranched polystyrene (HPS) and nitrogen-doped carbon nanotubes (NCNT) were investigated with respect to their potential environmental impacts and improvements if utilized in an industrially highly relevant process, namely glucose hydrogenation to sorbitol. The results of a comparative Life Cycle Assessment of the alternative catalytic systems under consideration of RANEY® nickel as benchmark catalyst revealed that in particular Ru nanoparticles on porous HPS beads processed under flow-chemistry conditions have the potential to improve the greenness of the overall synthesis, but the concentration of glucose in the reaction mixture is in fact the most influential parameter.

Effect of acidity and texture of micro-, mesoporous and hybrid micromesoporous materials on the synthesis of paramenthanic diol exhibiting anti-Parkinson activity

Abstract Microporous, mesoporous and new hybrid materials were studied in verbenol oxide isomerization for the synthesis of biologically active substance with anti-Parkinson activity. H-Si-MCM-41, H-Al-MCM-41, H-Al-MCM-48, H-Beta-25 and H-Beta-300 were compared with hybrid materials. The latter with a zeolite-like micro-mesoporous structure were characterized and evaluated for their catalytic activity for the first time. The approach of dual templating for synthesis of new materials was applied in this work to combine properties of Beta-zeolites and mesoporous cellular foams. The selectivity to the target product was the highest over microporous mild acidic H-Beta-300 and hybrid ZF-100, with also mild acidity and even absence of strong acid sites. Selectivity at 97% and 99% of conversion was 61% and 59% for H-Beta-300 and hybrid ZF-100, respectively.

Continuous hydrogenation of glucose with ruthenium on carbon nanotube catalysts

Continuous hydrogenation of glucose to sorbitol was studied in an experimental set-up with parallel screening multiphase reactors. After investigating a range of reaction parameters, the suitable conditions for catalyst screening were found to be 130 °C, 2.0 ml min−1 flow rate and 0.2 mol L−1 glucose concentration. The hydrogen pressure was kept at 20 bar under all reaction conditions investigated. A slate of different ruthenium supported on carbon (active carbon and carbon nanotubes) catalysts was screened. All catalysts showed high (>97.4%) selectivities to sorbitol, while activity and stability varied. Long-term evaluation of the two best catalysts was performed over a 100 h period.

On Synthesis and Characterization of Sulfated Alumina–Zirconia Catalysts for Isobutene Alkylation

The porous structure and surface acid–base properties of sulfated zirconia, alumina and alumina–zirconia applied in isobutylene alkylation were characterized using a variety of physico-chemical methods. Catalytic activity was related to catalyst physico-chemical properties.Graphical Abstract