Time filter

Source Type

Linkebeek, Belgium

Vitry V.,University of Mons | Nardone S.,Laborelec | Breyer J.-P.,Marichal Ketin | Sinnaeve M.,Marichal Ketin | Delaunois F.,University of Mons
Materials and Design | Year: 2012

High speed steels (HSS) present excellent hardness, wear resistance and high-temperature properties. These mechanical properties are due to the presence of a great amount of hard carbides in the martensitic matrix. In the last 10. years, Japanese rollmakers have developed HSS grades and introduced them into hot strip mills. The Marichal Ketin society (Liège, Belgium) has developed two grades of HSS: Kosmos and Aurora. Both grades present interesting properties but Aurora shows overall better performance than Kosmos, mainly because of a better distribution of harder (MC and M2C) carbides in the martensitic matrix. Moreover, the hardness of the Aurora grade stays constant in depth and can be strongly improved by heat treatment, due to secondary hardening. The purpose of this work is to describe the microstructure and the mechanical properties of the Kosmos and Aurora grades by various techniques such as optical microscopy, scanning electron microscopy (SEM), and macrohardness measurements. © 2011 Elsevier Ltd. Source

Khakharia P.,TNO | Brachert L.,Karlsruhe Institute of Technology | Mertens J.,Laborelec | Huizinga A.,TNO | And 4 more authors.
International Journal of Greenhouse Gas Control | Year: 2013

The prevention of emissions of amine species is of high importance for the overall sustainability and performance of Post Combustion CO2 Capture facilities. There is a clear understanding of amine emissions based on volatility in the treated flue gas. Emission via aerosols from Post Combustion CO2 Capture facilities has only been pointed out recently. Thus, there is little knowledge about emission via aerosols in contrast to emission based on volatility. It has been found that flue gas quality plays an important role for emissions caused by aerosols formation. In this work, we study the experimental assessment of the impact of flue gas quality on the level of monoethanolamine (MEA) emission via aerosols. In a dedicated test rig, effects of the flue gas components such as sulphuric acid aerosols and extremely fine particles like soot has been studied. An aerosol generator capable of producing controlled amounts of soot and dosing sulphuric acid aerosol to a mobile CO2 capture mini-plant was used as a test equipment for this study. Soot particle number concentration were in the range of 104-106 per cm3. The particle number concentration for different amount of H2SO4 aerosols were in the order of 108 per cm3. Amine emissions up to 4.3ppmv (12mg/Nm3 for MEA) is considered to be as an upper limit for the design of a Post Combustion CO2 Capture plant. MEA emissions in the presence of soot particles were in the range of 100-200mg/Nm3 which is 2-4 times higher than baseline vapour based emissions of about 45mg/Nm3. The expected particle size of H2SO4 aerosols is well below 100nm, while the corresponding mass concentration range is between 1 and 5mg/m3. The MEA emissions observed due to H2SO4 aerosols were in the range of 600-1100mg/Nm3. Moreover, parametric tests have shown that besides flue gas quality, the absorber temperature profile and the presence of CO2 in the flue gas are pre-requisite for aerosol emissions. It is evident that the observed level of emissions in this study are unacceptable. Therefore, it is imperative that fundamental know-how about aerosol formation and reduction is generated in order to design appropriate counter measures. © 2013 Elsevier Ltd. Source

Brachert L.,Karlsruhe Institute of Technology | Mertens J.,Laborelec | Khakharia P.,TNO | Schaber K.,Karlsruhe Institute of Technology
Journal of Aerosol Science | Year: 2014

In this study, two different methods for the measurement of the sulfuric acid aerosol which is formed in wet flue gas cleaning processes have been investigated. The condensation particle counter (UFCPC, PALAS GmbH) provides information about the number concentration. With the electrical low pressure impactor (ELPI+, Dekati Ltd.) also the size evaluation is possible. Both measurement methods reveal number concentrations above 108cm-3 under well controlled conditions in a pilot plant and the good conformance of the both methods is shown. With the ELPI+ the effect of dilution on the size of the volatile aerosol can be observed. The predicted trend of an existing simulation tool can be verified: the higher the sulfuric acid concentration, the larger are the droplet sizes. The number concentration, however, doesnD́t change considerably when altering the sulfuric acid concentration. © 2013 Elsevier Ltd. Source

Zurek J.,Julich Research Center | De Bruycker E.,Laborelec | Huysmans S.,Laborelec | Quadakkers W.J.,Julich Research Center
Corrosion | Year: 2014

In new and future generation power plants, creep-resistant steels selected for high-temperature components are subjected to several service environments. In many of these applications, water vapor has been found to substantially alter the technologically relevant properties, mainly growth rate and adherence, of the surface oxides. Various data sets exist in the literature for steam oxidation for this type of steel; however, these data show a substantial variability. These differences can be related to, e.g., "batch-to- batch" variations, oxidation conditions, surface treatment, and differences between laboratory/power plants data. Therefore, these literature data need careful and critical verification when being used to estimate the long-term materials behavior in real power generation plants. The paper discusses the existing steam oxidation data for the martensitic steels P91 (9%Cr-V-Mo), P92 (9%Cr-WV- Mo), and VM12 (12%Cr-Co-W-V-Mo), with the main emphasis on discussing the parameters that are responsible for the observed variations in oxidation rates for the various types of materials. Differences in minor alloying additions and surface treatment have as a result that for the 9%Cr steels the scale thickness after a given oxidation time may easily differ by a factor of two. Because of the "batch-to-batch variation" in oxidation behavior, the common procedure used to determine service temperatures of tubes made of low-Cr steels on the basis of measured oxide layer thicknesses, has to be used with some care in case of the 9% to 12%Cr martensitic steels. This is especially the case for the 12%Cr steels because their oxidation rates between 500°C and 650°C may not steadily increase with increasing temperature.© 2014, NACE International. Source

Mertens J.,Laborelec | Knudsen J.,DONG Energy | Thielens M.-L.,Laborelec | Andersen J.,DONG Energy
International Journal of Greenhouse Gas Control | Year: 2012

The study presents pioneering on-line emission data from a PCCC (post combustion carbon capture) pilot plant of both inorganic and organic components measured using an extractive FTIR (Fourier Transform Infra Red) system. A comparison with other emission measurements allowed concluding that the system is suitable as research tool for investigating the effect of PCCC operational settings on amine emissions. However, it also showed that sampling and analysing single organic components in flue gases is difficult and more research is needed on this topic. Linking the operational data of the plant with the on-line emission data identified two important operational settings that control the amine emissions from a PCCC plant to a large extent: (i) flue gas temperature at the top of the absorber (downstream of the washing section) and (ii) flue gas temperature difference over the washing section. A positive correlation between NH 3 emission and the O 2 content entering the pilot plant suggests that oxidative degradation occurs. The study emphasizes the importance of a well-designed washing section (if necessary, multi stage) which will be able to reduce emissions to very low levels keeping in mind the lessons learned in this study with respect to its operational settings. Therefore, the knowledge obtained within this research project will be of great use for the future post combustion carbon capture demo and full-scale installations. © 2011 Elsevier Ltd. Source

Discover hidden collaborations