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Fredericia, Denmark

DONG Energy ) is an integrated energy company based in Fredericia, Denmark. It is Denmark's largest energy company. Wikipedia.

Rasmussen H.,DONG Energy | Sorensen H.R.,DONG Energy | Meyer A.S.,Technical University of Denmark
Carbohydrate Research | Year: 2014

The degradation compounds formed during pretreatment when lignocellulosic biomass is processed to ethanol or other biorefinery products include furans, phenolics, organic acids, as well as mono- and oligomeric pentoses and hexoses. Depending on the reaction conditions glucose can be converted to 5-(hydroxymethyl)-2-furaldehyde (HMF) and/or levulinic acid, formic acid and different phenolics at elevated temperatures. Correspondingly, xylose can follow different reaction mechanisms resulting in the formation of furan-2-carbaldehyde (furfural) and/or various C-1 and C-4 compounds. At least four routes for the formation of HMF from glucose and three routes for furfural formation from xylose are possible. In addition, new findings show that biomass monosaccharides themselves can react further to form pseudo-lignin and humins as well as a wide array of other compounds when exposed to high temperatures. Hence, several aldehydes and ketones and many different organic acids and aromatic compounds may be generated during hydrothermal treatment of lignocellulosic biomass. The reaction mechanisms are of interest because the very same compounds that are possible inhibitors for biomass processing enzymes and microorganisms may be valuable biobased chemicals. Hence a new potential for industrial scale synthesis of chemicals has emerged. A better understanding of the reaction mechanisms and the impact of the reaction conditions on the product formation is thus a prerequisite for designing better biomass processing strategies and forms an important basis for the development of new biorefinery products from lignocellulosic biomass as well. © 2013 Elsevier Ltd. All rights reserved. Source

Nygaard N.G.,DONG Energy
Journal of Physics: Conference Series | Year: 2014

We present the first analysis of wake losses in some of the largest offshore wind farms built to date. In addition, we give an example of the external wake losses that can be imposed by a neighbouring wind farm. Both situations lend insights to the wake phenomena in large offshore wind farm clusters. A simple wake model is compared to the data to assess the need for a more detailed physical description of large wind farm wakes. © Published under licence by IOP Publishing Ltd. Source

Nguyen T.L.T.,University of Aarhus | Hermansen J.E.,University of Aarhus | Nielsen R.G.,DONG Energy
Journal of Cleaner Production | Year: 2013

This paper assesses the environmental performance of biomass gasification for electricity production based on wheat straw and compares it with that of alternatives such as straw-fired electricity production and fossil fuel-fired electricity production. In the baseline simulation, we assume that the combustion of biomass and fossil fuel references for electricity production takes place in a combined heat and power plant, but as a sensitivity analysis, we also consider combustion in a condensing mode power plant where only electricity is produced. Our results show that the production of 1 kWh of electricity from straw through gasification would lead to a global warming potential of 0.08 kg CO2e, non-renewable energy use of 0.2 MJ primary, acidification of 1.3 g SO2e, respiratory inorganics of 0.08 g PM2.5e and eutrophication potential of -1.9 g NO3e. The production of electricity from straw based on gasification technology appears to be more environmentally friendly than straw direct combustion in all impact categories considered. The comparison with coal results in the same conclusion as that reached in the comparison with straw direct combustion. The comparison with natural gas shows that using straw gas as an alternative energy source reduces global warming, non-renewable energy use and eutrophication but increases acidification and respiratory inorganics. The relative performance of straw gasification versus direct combustion and fossil fuel references does not change with varying assumptions about whether or not heat recovery is considered. © 2013 Elsevier Ltd. All rights reserved. Source

Toftegaard M.B.,Technical University of Denmark | Toftegaard M.B.,DONG Energy | Brix J.,Technical University of Denmark | Jensen P.A.,Technical University of Denmark | And 2 more authors.
Progress in Energy and Combustion Science | Year: 2010

Oxy-fuel combustion is suggested as one of the possible, promising technologies for capturing CO2 from power plants. The concept of oxy-fuel combustion is removal of nitrogen from the oxidizer to carry out the combustion process in oxygen and, in most concepts, recycled flue gas to lower the flame temperature. The flue gas produced thus consists primarily of carbon dioxide and water. Much research on the different aspects of an oxy-fuel power plant has been performed during the last decade. Focus has mainly been on retrofits of existing pulverized-coal-fired power plant units. Green-field plants which provide additional options for improvement of process economics are however likewise investigated. Of particular interest is the change of the combustion process induced by the exchange of carbon dioxide and water vapor for nitrogen as diluent. This paper reviews the published knowledge on the oxy-fuel process and focuses particularly on the combustion fundamentals, i.e. flame temperatures and heat transfer, ignition and burnout, emissions, and fly ash characteristics. Knowledge is currently available regarding both an entire oxy-fuel power plant and the combustion fundamentals. However, several questions remain unanswered and more research and pilot plant testing of heat transfer profiles, emission levels, the optimum oxygen excess and inlet oxygen concentration levels, high and low- temperature fire-side corrosion, ash quality, plant operability, and models to predict NOx and SO3 formation is required. © 2010 Elsevier Ltd. All rights reserved. Source

The present invention relates to a distributed electrical power system comprising a plurality of rechargeable power units such as electrical vehicles coupled to a common electrical power grid at remote locations. A dispatch controller is configured for controlling the supply of electrical power to the plurality of rechargeable power units in accordance with computed charge priorities.

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