Tanja Kolli

Biobutanol Production from Biomass

There is a demand for the increased production and usage of biofuels from both environmental and a political point of view. Biobutanol has great potential to become a novel replacement fuel for gasoline and diesel or an additive compound of these fuels in the future. This chapter reveals the superior fuel properties of butanol over ethanol, including better energy content, usability, safety, and easier distribution of the fuel. Traditional biochemical (acetone-butanol-ethanol fermentation) and chemical production processes of butanol are reviewed. In addition, the novel production routes of biobutanol are highlighted. Challenges in the implementation of feasible biochemical production processes of butanol in industrial scale include cost of raw materials, low product yield from fermentation, and expensive processing techniques. Process development techniques and different methods in order to increase the yield of fermentative butanol production by means of for instance new processing technologies and metabolic engineering are discussed.

Deactivation of Diesel Oxidation Catalysts by Sulphur in Laboratory and Engine-Bench Scale Aging

The activity of sulphur–water- and water-treated PtPd/Al2O3- and Pt/Al2O3-based monolith catalysts was investigated. The catalysts were characterized by X-ray photoelectron fluorescence, X-ray photoelectron spectroscopy, transmission electron microscopy and BET–BJH. The sulphur poisoning had a diminishing effect on the catalyst activity. The correlation between the laboratory-poisoned and engine-bench-aged catalyst activity was detected and found to have a relatively good correspondence.

Influence of OSC material on the behaviour of metallic Pd catalysts in C2H4 and CO oxidation as well as in NO reduction

The interaction of CO, C2H4, O2, and NO reaction gas compounds over the metallic Pd/Al2O3 and Pd/OSC/Al2O3 monoliths was investigated in order to understand the behaviour of OSC material in the oxidation and reduction reactions. FT-IR gas analyser was used for the analysis of the product gas composition. Several activity experiments carried out with dissimilar feedstreams have revealed that the CexZr1–xO2 mixed oxide is an oxygen storage compound, which promotes CO and C2H4 oxidation as well as NO reduction in particular at low temperatures.

Crown Ether Complexes of Six-Membered N-heteroaromatic Cations

Crown ether complexes of six-membered N-heteroaromatic cations and the closely related bicyclic purinium cation (6) have been studied by 1H NMR, mass spectrometric and crystallographic methods. The stability constants for the complexes were determined by 1H NMR titration in acetonitrile solution and the complexation stoichiometry by 1H NMR and ESI mass spectrometric methods. Altogether six crystal structures of complexes were determined to study the complexation in the solid state. Hydrogen bonding was observed to be the most important interaction for the complexation both in solution and in the solid state but π–π interactions also contribute to it. All crystal structures of the DB18C6 complexes with six-membered N-heteroaromatic cations, except for 4-hydroxypyridinium, are isomorphous to previously studied five-membered N-heteroaromatic cations and pyridinium complexes. Such a close resemblance is not observed in B18C6 and 18C6 complexes or DB18C6ċpurinium (6).

The Effect of Phosphorus Exposure on Diesel Oxidation Catalysts—Part II: Characterization of Structural Changes by Transmission Electron Microscopy

Abstract Phosphorus poisoning and its effect on the diesel oxidation catalysts morphology was studied by transmission electron microscopy (TEM). The studied catalyst samples were PtPd or Pt supported on the alumina-based washcoat including additives. The laboratory-scale phosphorus exposures were carried out with two different phosphorus concentrations. The cross-sectional TEM samples were prepared from the fresh and phosphorus-treated catalysts. After phosphorus exposures, significant structural changes were observed compared to the fresh catalysts. The shape of the noble metal particles had changed from irregular to more spherical-shaped particles. In addition, phosphorus was detected throughout the catalyst TEM samples but the amount varied depending on the local composition of the support. Phosphorus accumulated mainly in the alumina-containing areas of the support and indications of dense and amorphous aluminium phosphates were found. Based on the results gained, cross-sectional TEM characterization is essential to observe these kinds of morphological changes in the catalysts caused e.g. by phosphorus exposures. In addition, cross-sectional TEM samples are needed to study the effect of local variation in the support composition on the phosphorus accumulation.

The Effect of Biofuel Originated Potassium and Sodium on the NH3-SCR Activity of Fe–ZSM-5 and W–ZSM-5 Catalysts

The effect of potassium, sodium and water on Fe–ZSM-5, W–ZSM-5 and ZSM-5 catalysts was investigated. Catalysts were characterized by several techniques and tested in the NH3-SCR reaction. The impact of water-, K- and Na-treatments on the activity of catalysts was negligible. Thus, the catalysts can be concluded to be resistant to K- and Na-treatments.

Advances in catalysts for membrane reactors

Abstract: Membrane reactors with a catalyst bed are designed to be used in various reactions, such as hydrogenation, dehydrogenation, oxidation and reforming reactions. The catalyst can be introduced into the reactor as a bed in several ways in the form, for example, of pellets, extrudates or tablets; or it can be incorporated in the reactor as a catalytic membrane wall. However, in many cases, the studies concentrate on the membrane itself, the development of catalysts is ignored, and commercial catalysts are used in the experiments. Most of the catalysts tested are aluminium oxide (alumina, Al 2 O 3 ) based, as alumina is a mature support and already well proven in convectional reactors. However, some new catalyst materials such as carbon nanotubes (CNTs), carbon black, gels and anodic aluminium oxide (AAO) are developed as innovative catalyst supports and catalysts, since there is also a need for new catalysts for membrane reactors.

Partial oxidation (POX) processes and technology for clean fuel and chemical production

Abstract: Interest in partial oxidation (POX) has expanded because emissions reduction is a key topic in research and design of industrial processes. For example, hydrogen production from renewable sources is an important research area worldwide. POX processes operate with non-stoichiometric fuel-to-air mixtures, at high temperatures and elevated pressures. Catalytic partial oxidation (CPOX) enhances reactions; therefore operating temperature and pressure can be decreased. Problems include hot spots and poor heat conductivity in catalyst beds during very exothermic reactions. Efforts have been made to solve these problems in partial oxidation: fluidized bed reactors and using endothermic reactions such as steam reforming with POX. Catalysts based on nanomaterials and reactor systems using membranes, photocatalysis and microreactors have been developed to advance POX processes.