Modeling post-combustion CO2 capture with amine solvents

Poster (2010)

In order to avoid the emission of large amounts of greenhouse gas, CO2 capture in fossil fuel power plants and subsequent underground CO2 sequestration is studied. The capture occurs by reactive CO2 ... [more ▼]

In order to avoid the emission of large amounts of greenhouse gas, CO2 capture in fossil fuel power plants and subsequent underground CO2 sequestration is studied. The capture occurs by reactive CO2 absorption into chemical solvent systems at moderate temperature (~50°C) followed by solvent regeneration at higher temperature (~120°C). So far, the most employed solvent for acid gas capture is monoethanolamine (MEA). One main drawback of this technology is the high energy consumption necessary to regenerate the solvent. In the present work, the CO2 capture process with MEA is modeled using the simulation tool Aspen Plus®. The base case process is optimized and some process improvements are studied that imply a significant decrease of the process exergy consumption. [less ▲]

Recovery boiler monitoring : steam flow prediction with random forests

Poster (2010)

Variance of Estimates in Dynamic Data Reconciliation

(2009, June 14)

Propulsion vehicle integration for reusable launcher using in-flight oxygen collection

in Aerospace Science and Technology (2008), 12(6), 429-435

The use of in-flight oxygen collection has shown to significantly improve space launcher performance. The conceptual approach followed by Belgian teams working on oxygen collection has been to try to ... [more ▼]

The use of in-flight oxygen collection has shown to significantly improve space launcher performance. The conceptual approach followed by Belgian teams working on oxygen collection has been to try to widening the available design margins in order to reduce the required technological leap and limit the economical risk associated with such a development. The aim of the ESA-funded theoretical and experimental study on an air separation device is to demonstrate the possibility of performing efficient air distillation in a compact rotating column. An integration of the vehicle, propulsion system and separation unit designs is presented. The objective is to optimise the overall vehicle performance while keeping technological difficulty and system complexity at a reasonable level. Reference vehicles are presented within their specific mission profiles with an emphasis on TSTO's. Different layouts of the internal energy and mass flowsheets have been studied and were compared in order to make best use of the refrigeration capacity of the hydrogen fuel running through the propulsion system during the first phase of the flight. In those flowsheets, the separator is considered as a classical distillation tray column. That analysis provides the requirements in terms of heat exchange capacity, compression ratios and number of so-called transfer units needed in the separator. The system is intentionally kept simple to limit complexity, but the analysis is thorough and accurate, including, for example, the effect of the presence of argon. Results for a supersonic carrier are presented. A compact separation unit has been designed in order to reach those requirements. That includes internals, practical building with estimates of pressure drops, separation performance and flow limitation. Main results are given, sizing of the separator bed is provided for a carrier plane showing that such on-board separator is indeed practical. (C) 2007 Elsevier Masson SAS. All rights reserved. [less ▲]

Suivi de performances et optimisation de procédés industriels

Poster (2008)

Propulsion vehicle integration for reusable launcher using in-flight oxygen collection

in Aerospace Science and Technology (2007), 12

The use of in-flight oxygen collection has shown to significantly improve space launcher performance. The conceptual approach followed by Belgian teams working on oxygen collection has been to try to ... [more ▼]

The use of in-flight oxygen collection has shown to significantly improve space launcher performance. The conceptual approach followed by Belgian teams working on oxygen collection has been to try to widening the available design margins in order to reduce the required technological leap and limit the economical risk associated with such a development. The aim of the ESA-funded theoretical and experimental study on an air separation device is to demonstrate the possibility of performing efficient air distillation in a compact rotating column. An integration of the vehicle, propulsion system and separation unit designs is presented. The objective is to optimise the overall vehicle performance while keeping technological difficulty and system complexity at a reasonable level. Reference vehicles are presented within their specific mission profiles with an emphasis on TSTO’s. Different layouts of the internal energy and mass flowsheets have been studied and were compared in order to make best use of the refrigeration capacity of the hydrogen fuel running through the propulsion system during the first phase of the flight. In those flowsheets, the separator is considered as a classical distillation tray column. That analysis provides the requirements in terms of heat exchange capacity, compression ratios and number of so-called transfer units needed in the separator. The system is intentionally kept simple to limit complexity, but the analysis is thorough and accurate, including, for example, the effect of the presence of argon. Results for a supersonic carrier are presented. A compact separation unit has been designed in order to reach those requirements. That includes internals, practical building with estimates of pressure drops, separation performance and flow limitation. Main results are given, sizing of the separator bed is provided for a carrier plane showing that such on-board separator is indeed practical. [less ▲]

Carbon nanotubes synthesis by CCVD process : kinetic study on a Fe-Co/Al2O3 catalyst

in Carbon (2007), 45(6), 1167-1175

A kinetic study was performed to describe the initial specific rate of multi-walled carbon nanotube synthesis by catalytic chemical vapor deposition (CCVD) on a bimetallic cobalt-iron catalyst at high ... [more ▼]

A kinetic study was performed to describe the initial specific rate of multi-walled carbon nanotube synthesis by catalytic chemical vapor deposition (CCVD) on a bimetallic cobalt-iron catalyst at high temperature using ethylene decomposition to solid carbon and gaseous hydrogen. The study uses a mass spectrometer that allows reaction rate to be inferred from the exhaust gas composition measurements. The aim is to obtain a better understanding of the elementary steps involved in the production of carbon nanotubes so as to derive phenomenological kinetic models in agreement with experimental data. The best models assume the elimination of the first hydrogen atom from adsorbed ethylene as rate determining step and involve a hydrogen adsorption weak enough to be neglected. It was proved that hydrogen partial pressure has no influence on initial reaction rate of carbon nanotube synthesis with the catalyst used for this study. Activation energy and ethylene adsorption enthalpy were found to be equal to around 130 and - 130 kJ mol(-1), respectively. (C) 2007 Elsevier Ltd. All rights reserved. [less ▲]

A kinetic study of multi-walled carbon nanotube synthesis by catalytic chemical vapor deposition using a Fe-Co/Al2O3 catalyst

in Carbon (2007), 45(6), 1167-1175

A kinetic study was performed to describe the initial specific rate of multi-walled carbon nanotube synthesis by catalytic chemical vapor deposition (CCVD) on a bimetallic cobalt-iron catalyst at high ... [more ▼]

A kinetic study was performed to describe the initial specific rate of multi-walled carbon nanotube synthesis by catalytic chemical vapor deposition (CCVD) on a bimetallic cobalt-iron catalyst at high temperature using ethylene decomposition to solid carbon and gaseous hydrogen. The study uses a mass spectrometer that allows reaction rate to be inferred from the exhaust gas composition measurements. The aim is to obtain a better understanding of the elementary steps involved in the production of carbon nanotubes so as to derive phenomenological kinetic models in agreement with experimental data. The best models assume the elimination of the first hydrogen atom from adsorbed ethylene as rate determining step and involve a hydrogen adsorption weak enough to be neglected. It was proved that hydrogen partial pressure has no influence on initial reaction rate of carbon nanotube synthesis with the catalyst used for this study. Activation energy and ethylene adsorption enthalpy were found to be equal to around 130 and - 130 kJ mol(-1), respectively. (C) 2007 Elsevier Ltd. All rights reserved. [less ▲]

Comparaison de techniques de validation dynamique de données

(2006, October)

Experimental Study Of An In-Flight Air Separation Device

in AIAA/CIRA 13th International Space Planes and Hypersonics Systems and Technologies Conference (2005, May)

Intending to provide in-flight Oxygen Collection capability to new launchers, a subscale model of a centrifugally enhanced air distillation unit is under development. The vehicle we foresee for this ... [more ▼]

Intending to provide in-flight Oxygen Collection capability to new launchers, a subscale model of a centrifugally enhanced air distillation unit is under development. The vehicle we foresee for this application is described elsewhere, the present paper concentrating only on the technological and experimental aspects. While the test setup has already been shown to be able to provide the adequate cooling power, the rig is still under construction. The experimental and technical aspects include choices and main trade-offs that had to be made during the design process. Of particular interest are the stainless steel all welded heat exchangers allowing for deep cooling and liquefaction of air from the main compressor and dryers. Specifically, developed hardware is described in details. On the test rig side, design of the rotating cryogenic separator is explained, including mechanical aspects, heat management and sealing. The whole system has modes of operation allowing, among other parameters, to explore various air compositions and mass flows rates on the gaseous and liquid sides. Perspectives are given for the testing of the separator. [less ▲]