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Salehi K.,TU Hamburg - Harburg | Kordsachia O.,Thunen Institute of Wood Research | Patt R.,TU Hamburg - Harburg
Industrial Crops and Products | Year: 2014

MEA (monoethanolamine)/AQ pulping of wheat and rye straw and bleaching of the produced pulps were investigated. The delignification behaviour of wheat and rye straw using varying MEA/water and liquor/straw ratios was studied. Furthermore, the impacts of mono-, di-, tri-ethanolamine/water mixtures and addition of KOH to the cooking liquor were monitored. The best results were achieved with a MEA/water ratio of 50/50 at a liquor/straw ratio between 3:1 and 4:1. The use of the mixture of mono-, di-, tri-ethanolamine instead of MEA only was not effective for straw pulping. The effect of adding KOH to the MEA pulping liquor was negligible. The results of MEA pulping of both straw species were compared with results for production and bleaching of soda and soda/AQ reference pulps. At similar degree of delignification, the MEA pulps showed 10% higher yield (based on straw), which demonstrates the unusually high selectivity of MEA in straw pulping. The MEA straw pulps showed fairly low brightness and were more difficult to bleach than the corresponding soda pulps. Nevertheless, it is possible to bleach MEA pulps to more than 80% ISO brightness, applying an ECF bleaching sequences (O-Q-OP-DQ-P). With regard to bleachability, yield and strength properties the rye straw pulp sample performed much better than wheat straw pulp sample. © 2013 Elsevier B.V. Source

Elliott D.C.,Pacific Northwest National Laboratory | Oasmaa A.,VTT Technical Research Center of Finland | Meier D.,Thunen Institute of Wood Research | Preto F.,CANMET Energy | Bridgwater A.V.,Aston University
Energy and Fuels | Year: 2012

An international round robin study of the viscosity measurements and aging of fast pyrolysis bio-oil has been undertaken recently, and this work is an outgrowth from that effort. Two bio-oil samples were distributed to two laboratories for accelerated aging tests and to three laboratories of long-term aging studies. The accelerated aging test was defined as the change in viscosity of a sealed sample of bio-oil held for 24 h at 80 °C. The test was repeated 10 times over consecutive days to determine the intra-laboratory repeatability of the method. Other bio-oil samples were placed in storage at three temperatures, 21, 5, and -17 °C, for a period of up to 1 year to evaluate the change in viscosity. The variation in the results of the accelerated aging test was shown to be low within a given laboratory. The long-term aging studies showed that storage of a filtered bio-oil under refrigeration can minimize the amount of change in viscosity. The accelerated aging test gave a measure of change similar to that of 6-12 months of storage at room temperature for a filtered bio-oil. Filtration of solids was identified as a key contributor to improving the stability of the bio-oil as expressed by the viscosity based on results of the accelerated aging tests as well as long-term aging studies. Only the filtered bio-oil consistently gave useful results in the accelerated aging and long-term aging studies. The inconsistency suggests that better protocols need to be developed for sampling bio-oils. These results can be helpful in setting standards for use of bio-oil, which is just coming into the marketplace. © 2012 American Chemical Society. Source

Meier D.,Thunen Institute of Wood Research | Van De Beld B.,BTG | Bridgwater A.V.,Aston University | Elliott D.C.,Pacific Northwest National Laboratory | And 2 more authors.
Renewable and Sustainable Energy Reviews | Year: 2013

Fast pyrolysis of biomass is becoming increasingly important in some member countries of the International Energy Agency (IEA). Six countries have joined the IEA Task 34 of the Bioenergy Activity: Canada, Finland, Germany, Netherlands, UK, and USA. The National Task Leaders give an overview of the current activities in their countries both on research, pilot and demonstration level. © 2012 Elsevier Ltd. Source

The study deals with younger glacial history (<5500 BP) of some remote high valleys in the Inner Himalaya. Field survey, geomorphological mapping, photo comparisons, equilibrium line altitude (ELA) lowerings, lichen findings as well as one radiocarbon date provide insights in the former behaviour of 25 subcontinental glaciers. Each glacier forefield is bordered by great lateral moraines, propably indicating the historical maximum glaciation (stage 1, <1700 yr. BP). Outside the forefield deposits occur moraine walls that were deposited during the neoglacial period (5500-2000 yr. BP). The last build up of the stage 1-moraines most likely took place during the Little IceAge (LIA)maximum(AD1600-1800). Between the stage 1-moraines and the present glacier snouts, threemore glacier stages (2, 3 and 4) were mapped. Stages 2 and 3 could be correlated to cold and humid phases in the first half of the 19th century and in the beginning of the 20th century. Photographic material documents that the stage 4-moraines were deposited from ca. AD 1974 to 1980. The very similar moraine sequences in each glacier forefield, as well as the consistently documented glacier stage 4 around 1974 to 1980, support the hypothesis that the snouts of the comparably small (due to their low avalanche nourishment) and debris poor glaciers in the Inner Himalaya, respond relatively directly to climate signals. © 2014 by the Wadia Institute of Himalayan Geology, Dehradun 248001, India. Source

Brischke C.,Leibniz University of Hanover | Melcher E.,Thunen Institute of Wood Research
Wood Science and Technology | Year: 2015

While, for instance, oils and waxes were found to be promising for protecting wood under laboratory test conditions, long-term outdoor experience with these materials is limited. This study aimed at investigating the performance of wax-treated wood exposed aboveground in double-layer and lap-joint configurations. Wetting resistance, susceptibility to checking and durability were investigated over several years. All wax-treated wood performed better in the lap-joint exposure than in double layer, which was characterized by severe moisture trapping. However, durability and moisture performance were considerably better compared to untreated controls, but diminished with increasing exposure time. Already after 1 year of exposure, the number of cracks on lap-joint specimens was nearly identic between treated and untreated samples. Due to the wax migration observed during exposure, the formation of checks, accumulation of water in treated samples and partial infection, it can be concluded that the chosen synthetic wax types are not recommendable for practical applications. On the other hand, the principle of wood protection through moisture protection became evident in the aboveground field tests: As long as moisture exclusion was assured, the development of decay was inhibited. © 2014, Springer-Verlag Berlin Heidelberg. Source

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