Christian Hulteberg

Biological valorization of low molecular weight lignin.

Lignin is a major component of lignocellulosic biomass and as such, it is processed in enormous amounts in the pulp and paper industry worldwide. In such industry it mainly serves the purpose of a fuel to provide process steam and electricity, and to a minor extent to provide low grade heat for external purposes. Also from other biorefinery concepts, including 2nd generation ethanol, increasing amounts of lignin will be generated. Other uses for lignin - apart from fuel production - are of increasing interest not least in these new biorefinery concepts. These new uses can broadly be divided into application of the polymer as such, native or modified, or the use of lignin as a feedstock for the production of chemicals. The present review focuses on the latter and in particular the advances in the biological routes for chemicals production from lignin. Such a biological route will likely involve an initial depolymerization, which is followed by biological conversion of the obtained smaller lignin fragments. The conversion can be either a short catalytic conversion into desired chemicals, or a longer metabolic conversion. In this review, we give a brief summary of sources of lignin, methods of depolymerization, biological pathways for conversion of the lignin monomers and the analytical tools necessary for characterizing and evaluating key lignin attributes.

Pore Condensation in Glycerol Dehydration

Pore condensation followed by polymerization is proposed as an explanatory model of several observations reported in the literature regarding the dehydration of glycerol to acrolein. The major conclusion is that glycerol pore condensation in the micro- and mesopores, followed by polymerization in the pores, play a role in catalyst deactivation.

Small Scale Reformers for on-site Hydrogen Supply

Abstract This paper presents the major outcome of the IEA Hydrogen Implementing Agreement (IEA-HIA) Task 23 “Small-scale reforming for on-site hydrogen supply”. The task is briefly described, including the three sub-tasks: harmonized industrialization, sustainability and renewables and market information. An exclusive network of worldwide suppliers of reformers as well as gas companies has contributed to the discussion, evaluation and harmonization of on-site production technologies and optimal use of feedstock. The ambition has been to contribute to harmonization of capacities and improved system performance to facilitate both reduced system and production costs.

Techno-economics of carbon preserving butanol production using a combined fermentative and catalytic approach

This paper presents a novel process for n-butanol production which combines a fermentation consuming carbon dioxide (succinic acid fermentation) with subsequent catalytic reduction steps to add hydrogen to form butanol. Process simulations in Aspen Plus have been the basis for the techno-economic analyses performed. The overall economy for the novel process cannot be justified, as production of succinic acid by fermentation is too costly. Though, succinic acid price is expected to drop drastically in a near future. By fully integrating the succinic acid fermentation with the catalytic conversion the need for costly recovery operations could be reduced. The hybrid process would need 22% less raw material than the butanol fermentation at a succinic acid fermentation yield of 0.7g/g substrate. Additionally, a carbon dioxide fixation of up to 13ktonnes could be achieved at a plant with an annual butanol production of 10ktonnes.

Small-Scale Reforming for On-Site Hydrogen Supply

This chapter describes small-scale reforming for on-site production of hydrogen. By small scale is meant a production rate higher than 50Nm3h-1. First, an overview of the reformer technology and feedstock options is given and hydrogen purity issues are discussed. Second, examples of suppliers and cost trends are presented. Finally, research related to progress in materials, development of more robust catalysts, reactor improvements, more compact clean-up components as well as improved safety and control methods is discussed. Technology options for small-scale carbon capture are briefly presented.

Catalytic Abatement of NH3 Using NOx in Reducing Environment

Removal of ammonia from synthesis gas is an important step in gas purification to prevent poisoning of downstream catalyst or formation of nitrogen oxides on combustion. This publication proposes that ammonia can be removed by using selective catalytic abatement with NOx, not unlike the selective catalytic reduction of NOx but under reducing environment. Two different catalysts have been used for the experiments; V2O5/WO3/TiO2 and H-mordenite. The conducted experiments were performed on a model synthesis gas and served to investigate the selectivity and to some extent the longevity of these catalysts under reducing atmosphere, and also the effect of water on the catalyst performance. A number of catalyst characterisation methods have been used to obtain a better understanding of the catalyst morphology and surface. The methods that have been used are Raman spectroscopy, Brunauer–Emmett–Teller nitrogen adsorption, X-ray diffraction and temperature programmed desorption using ammonia. The initial performance with respect to conversion and selectivity is good for the vanadia-based catalyst, but it is not chemically stable. This is manifested by a change in the catalyst crystal structure suggesting an oxygen depletion of the titania support and decreased activity with time-on-stream. The mordenite catalyst is stable but the activity and selectivity, especially to avoid the formation of N2O, needs to be improved before implementation. Based on the experimental work performed, none of the catalysts in their present state are suitable for the proposed operating conditions.