Testing of CO2 Specifications With Respect to Corrosion and Bulk Phase Reactions

AbstractCaptured anthropogenic CO2 contains impurities that might react and form solids and separate corrosive phases when the impurity concentrations exceed the limit where the impurity combination becomes thermodynamically unstable. A number of tentative CO2 specifications and recommendations for the maximum acceptable impurity concentrations have been published. The recommendations include impurity combinations and impurity levels that are not found in the published CO2 specifications for pipelines that are or have been in operation. The lack of field experience and the lack of published lab data that support these specifications are a concern.The most referred recommendations have been challenged in the present work. Experiments were performed with dense phase CO2 containing 300 ppmv water, 350 ppmv O2, 100 ppmv SO2, 100 ppmv NO2 and 100 ppmv H2S. The CO2 and the impurities were continuously injected in the test autoclaves and the consumption rate of the impurities was measured. The experiments showed that the carbon steel corroded and that elemental sulfur formed together with a liquid phase containing sulfuric and nitric acid.The paper discusses the experimental technique and the results obtained in four autoclave experiments. The paper also discusses how the lack of fundamental data and understanding makes it difficult to predict corrosion rates and define a safe operation window for transport of dense phase CO2 originating from different sources with different contaminants

Experimental and numerical model study of the limiting current in a channel flow cell with a circular electrode

We describe first measurement in a novel thin-layer channel flow cell designed for the investigation of heterogeneous electrocatalysis on porous catalysts. For the interpretation of the measurements, a macroscopic model for coupled species transport and reaction, which can be solved numerically, is feasible. In this paper, we focus on the limiting current. We compare numerical solutions of a macroscopic model to a generalization of a Leveque-type asymptotic estimate for circular electrodes, and to measurements obtained in the aforementioned flow cell. We establish, that on properly aligned meshes, the numerical method reproduces the asymptotic estimate. Furthermore, we demonstrate, that the measurements are partially performed in the sub-asymptotic regime, in which the boundary layer thickness exceeds the cell height. Using the inlet concentration and the diffusion coefficient from literature, we overestimate the limiting current. On the other hand, the use of fitted parameters leads to perfect agreement between model and experiment

Ammonia as Hydrogen Carrier. Effects of Ammonia on Polymer Electrolyte Membrane Fuel Cells

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Ammonia as Hydrogen Carrier. Effects of Ammonia on Polymer Electrolyte Membrane Fuel Cells

dr.ing.dr.ing