Peter Arendt Jensen

Bio: Peter Arendt Jensen is an academic researcher from Technical University of Denmark. The author has contributed to research in topics: Pyrolysis & Combustion. The author has an hindex of 54, co-authored 217 publications receiving 10513 citations.

A review of catalytic upgrading of bio-oil to engine fuels

Abstract: As the oil reserves are depleting the need of an alternative fuel source is becoming increasingly apparent. One prospective method for producing fuels in the future is conversion of biomass into bio-oil and then upgrading the bio-oil over a catalyst, this method is the focus of this review article. Bio-oil production can be facilitated through flash pyrolysis, which has been identified as one of the most feasible routes. The bio-oil has a high oxygen content and therefore low stability over time and a low heating value. Upgrading is desirable to remove the oxygen and in this way make it resemble crude oil. Two general routes for bio-oil upgrading have been considered: hydrodeoxygenation (HDO) and zeolite cracking. HDO is a high pressure operation where hydrogen is used to exclude oxygen from the bio-oil, giving a high grade oil product equivalent to crude oil. Catalysts for the reaction are traditional hydrodesulphurization (HDS) catalysts, such as Co–MoS2/Al2O3, or metal catalysts, as for example Pd/C. However, catalyst lifetimes of much more than 200 h have not been achieved with any current catalyst due to carbon deposition. Zeolite cracking is an alternative path, where zeolites, e.g. HZSM-5, are used as catalysts for the deoxygenation reaction. In these systems hydrogen is not a requirement, so operation is performed at atmospheric pressure. However, extensive carbon deposition results in very short catalyst lifetimes. Furthermore a general restriction in the hydrogen content of the bio-oil results in a low H/C ratio of the oil product as no additional hydrogen is supplied. Overall, oil from zeolite cracking is of a low grade, with heating values approximately 25% lower than that of crude oil. Of the two mentioned routes, HDO appears to have the best potential, as zeolite cracking cannot produce fuels of acceptable grade for the current infrastructure. HDO is evaluated as being a path to fuels in a grade and at a price equivalent to present fossil fuels, but several tasks still have to be addressed within this process. Catalyst development, understanding of the carbon forming mechanisms, understanding of the kinetics, elucidation of sulphur as a source of deactivation, evaluation of the requirement for high pressure, and sustainable sources for hydrogen are all areas which have to be elucidated before commercialisation of the process.

Transformation and Release to the Gas Phase of Cl, K, and S during Combustion of Annual Biomass

Abstract: The transformation of inorganic constituents in annual biomass was experimentally investigated at grate-combustion conditions. A laboratory fixed-bed reactor was applied to obtain quantitative information of the release of Cl, K, and S to the gas phase from six distinctively different annual biomass fuels. Samples of 4.0 g of biomass were combusted at well-controlled conditions at temperatures from 500 to 1150 °C. The elemental release was quantified by analysis of the residual ash and a mass balance on the system. The experimental results revealed that potassium was released to the gas phase in significant amounts at combustion above 700 °C. The potassium release increased with the applied combustion temperature for all biomass fuels; however, the quantity released was largely determined by the ash composition. At 1150 °C, between 50 and 90% of the total potassium was released to the gas phase. The biomass fuels with an appreciable content of silicate showed the lower release of potassium. Between 25 and...

Experimental Investigation of the Transformation and Release to Gas Phase of Potassium and Chlorine during Straw Pyrolysis

Abstract: When straw undergoes thermal treatment the initial process is a pyrolysis at which some K and Cl can be volatilized, and this may result in problems with deposit formation and corrosion of the reactor containment. A laboratory batch reactor was applied to study the release and transformation of K and Cl as a function of temperature, at an initial heating rate of approximately 50 °C/s. To facilitate the interpretation of the batch reactor experiments thermodynamic equilibrium calculations at reducing condition were conducted, and SEM (scanning electron microscopy) and leaching investigations were carried out on straw and char samples. The experiments showed that chlorine was released in two steps, about 60% was released when the temperature increased from 200 to 400 °C and most of the residual chlorine was released between 700 and 900 °C. Below 700 °C no significant potassium release was observe; above that temperature it increased progressively until about 25% potassium release at 1050 °C. During pyrolysi...

Screening of Catalysts for Hydrodeoxygenation of Phenol as a Model Compound for Bio-oil

Abstract: Four groups of catalysts have been tested for hydrodeoxygenation (HDO) of phenol as a model compound of bio-oil, including oxide catalysts, methanol synthesis catalysts, reduced noble metal catalysts, and reduced non-noble metal catalysts. In total, 23 different catalysts were tested at 100 bar H2 and 275 °C in a batch reactor. The experiments showed that none of the tested oxides or methanol synthesis catalysts had any significant activity for phenol HDO under the given conditions, which were linked to their inability to hydrogenate the aromatic ring of phenol. HDO of phenol over reduced metal catalysts could effectively be described by a kinetic model involving a two-step reaction in which phenol initially was hydrogenated to cyclohexanol and then subsequently deoxygenated to cyclohexane. Among reduced noble metal catalysts, ruthenium, palladium, and platinum were all found to be active, with activity decreasing in that order. Nickel was the only active non-noble metal catalyst. For nickel, the effect o...

Catalytic Transformation of Lignin for the Production of Chemicals and Fuels

Abstract: and Fuels Changzhi Li,† Xiaochen Zhao,† Aiqin Wang,† George W. Huber,†,‡ and Tao Zhang*,† †State Key Laborotary of Catalysis, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China ‡Department of Chemical and Biological Engineering, University of WisconsinMadison, Madison, Wisconsin 53706, United States

Carbon capture and storage update

Abstract: In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coal (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.