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Bad Essen, Germany

Open Grid Europe is Germany's leading natural gas transmission company. Open Grid Europe plans, constructs, operates and monitors the country's largest natural gas transmission system, with a total length of about 12,000 km. The natural gas transmission within the OGE pipeline system will be realized by the use of compressor stations. On the compressor station in Köln-Porz a gas turbine was upgraded in 2010 using OGE developed technology, which is suitable to meet tighter environmental regulations. Using the example of the gas turbine Frame 3R DLE the following article shows how an oldie is kept fit for the future. Source

Benten R.,Open Grid Europe GmbH | Steiner K.,E.ON | Uhl P.,HGC Hamburg Gas Consult | Dirk Weissenfels W.,E.ON
GWF, Gas - Erdgas

Local biogas production and supply via natural gas networks gains increasing market potential. It modifies gas deliveries by adding carbon neutral biomethan. Pressure regulating and metering stations enable network access thereby connecting biogas production to the supply infrastructure. Standarized network access solutions provide advantages to grid operators and traders. It limits cost and guaranties transparent project courses. Furthermore, proven technology secures reliability of supply. E.ON Ruhrgas solutions are described, regulatory terms and conditions of network access discussed, and advantages to operators and traders exemplified. Source

Schmitt G.,Institute for Maintenance and Corrosion Protection Technologies gGmbH | Schoeneich H.-G.,Open Grid Europe GmbH | Siegmund G.,ExxonMobil
NACE - International Corrosion Conference Series

The paper reports on the influence of alternating current (AC) on the hydrogen uptake of X80 pipeline steel cathodically polarized with a constant current density of -100 A/m2 in different media (0.2 M Na2SO4, 0.2 M and 0.8 M NaOH, 0.2 M NaCl/MgCl2/CaCl2, artificial soil solution) at room temperature. Under these conditions AC current densities of 30, 100 and 500 A/m2 were applied. While the Devanathan-Stachurski method was not successful to indicate AC effects on hydrogen permeation, the volumetric quantification of hydrogen permeation proved its feasibility. In the absence of promoters (e.g. arsenite) no hydrogen permeation was measured in all media regardless of the presence of AC (30 to 500 A/m2). Hydrogen permeation started only after addition of a promotor. In NaOH solution containing arsenite as promotor a small AC effect could be detected which, however, led to a small reduction of the hydrogen permeation rate. The effect was more visible at high AC current densities (e.g. 500 A/m2). As a side effect, intergranular 'cathodic' iron dissolution with formation of intergranular pits was found in promotor-free 0.2 M NaCl/MgCl2/CaCl2 solution. Within 24 h pit depths of 50 μm (some grain layers) could be formed in combination with Fe-, Ca- and Mg-containing deposits exhibiting filigree structures. In the presence of AC the formation of such deposits and scales was retarded. The mechanism of this 'cathodic' iron dissolution is discussed. During the experimental investigations no indications were found that AC can favor hydrogen related failure mechanisms at high strength pipeline steels under cathodic corrosion protection. © 2015 by Nace International. Source

Schmitt G.,Institute for Maintenance and Corrosion Protection Technology gGmbH | Forster R.,Open Grid Europe GmbH
NACE - International Corrosion Conference Series

Magnetite as the major part of black powder encountered in transmission pipelines all over the world can form galvanic elements with the pipeline steel, provided a liquid film with some ionic conductivity is present. This galvanic element can exist also in the absence of water, provided other compounds are present to assure some ionic conductivity, e.g. organic acids like formic acid, acetic acid, acetates, or ammonium compounds from inhibitor packages. In this galvanic element iron forms the anode and magnetite the surface for the cathodic reaction. The element currents are in the μA range and increase with increasing ionic conductivity, with increasing temperature, with increasing oxygen partial pressure, and specifically with the ratio of cathodic and anodic surface A pronounced increase of the element current was observed at oxygen partial pressures as low as 200 mbar in the gas. Element currents measured under pipeline relevant filming conditions can cause iron dissolution rates well over the target penetration rate of 0.1 mm/y. © 2015 by Nace International. Source

Pfetsch M.E.,TU Darmstadt | Fugenschuh A.,Helmut Schmidt University | Geissler B.,Friedrich - Alexander - University, Erlangen - Nuremberg | Geissler N.,Open Grid Europe GmbH | And 17 more authors.
Optimization Methods and Software

In this article, we investigate methods to solve a fundamental task in gas transportation, namely the validation of nomination problem: given a gas transmission network consisting of passive pipelines and active, controllable elements and given an amount of gas at every entry and exit point of the network, find operational settings for all active elements such that there exists a network state meeting all physical, technical, and legal constraints. We describe a two-stage approach to solve the resulting complex and numerically difficult non-convex mixed-integer nonlinear feasibility problem. The first phase consists of four distinct algorithms applying mixed-integer linear, mixed-integer nonlinear, nonlinear, and methods for complementarity constraints to compute possible settings for the discrete decisions. The second phase employs a precise continuous nonlinear programming model of the gas network. Using this setup, we are able to compute high-quality solutions to real-world industrial instances that are significantly larger than networks that have appeared in the mathematical programming literature before. © 2014 Taylor & Francis. Source

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