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See detailAssessment of Solvent Degradation within a Global Process Model of Post-Combustion CO2 Capture
Léonard, Grégoire ULg; Heyen, Georges ULg; Toye, Dominique ULg

Conference (2014, June 17)

Solvent degradation may be a major drawback for the large-scale implementation of post-combustion CO2 capture due to amine consumption and emission of degradation products. However, its influence on the ... [more ▼]

Solvent degradation may be a major drawback for the large-scale implementation of post-combustion CO2 capture due to amine consumption and emission of degradation products. However, its influence on the process operations has rarely been studied. In the present work, a kinetics model describing solvent oxidative and thermal degradation has been developed based on own experimental results for the benchmark solvent, i.e. 30 wt% monoethanolamine (MEA) in water. This model has been included into a global Aspen Plus model of the CO2 capture process. The selected process modelling approaches are described in the present work. Using the resulting simulation model, optimal operating conditions can be identified to minimize both the energy requirement and the solvent degradation in the process. This kind of process model assessing solvent degradation may contribute to the design of large-scale CO2 capture plants to consider not only the process energy penalty, but also its environmental penalty. Indeed, both aspects are relevant for the large-scale deployment of the CO2 capture technology. [less ▲]

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See detailAssessment of Solvent Degradation within a Global Process Model of Post-Combustion CO2 Capture
Léonard, Grégoire ULg; Toye, Dominique ULg; Heyen, Georges ULg

in Computer Aided Chemical Engineering (2014), 33

Solvent degradation may be a major drawback for the large-scale implementation of post-combustion CO2 capture due to amine consumption and emission of degradation products. However, its influence on the ... [more ▼]

Solvent degradation may be a major drawback for the large-scale implementation of post-combustion CO2 capture due to amine consumption and emission of degradation products. However, its influence on the process operations has rarely been studied. In the present work, a kinetics model describing solvent oxidative and thermal degradation has been developed based on own experimental results for the benchmark solvent, i.e. 30 wt% monoethanolamine (MEA) in water. This model has been included into a global Aspen Plus model of the CO2 capture process. The selected process modelling approaches are described in the present work. Using the resulting simulation model, optimal operating conditions can be identified to minimize both the energy requirement and the solvent degradation in the process. This kind of process model assessing solvent degradation may contribute to the design of large-scale CO2 capture plants to consider not only the process energy penalty, but also its environmental penalty. Indeed, both aspects are relevant for the large-scale deployment of the CO2 capture technology. [less ▲]

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See detailModeling post-combustion CO2 capture with assessment of solvent degradation
Léonard, Grégoire ULg; Belletante, Ségolène; Cabeza Mogador, Bruno et al

Conference (2013, October)

Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy ... [more ▼]

Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy demand. CO2 is chemically absorbed in an amine solvent that can be regenerated at higher temperature, producing a pure CO2 stream. However, the large impact of this technology on the power plant efficiency and the environmental penalty are the main drawbacks for large-scale implementation. In this work, an innovative approach combining process modeling and evaluation of the environmental penalty due to amine degradation is presented. Based on experimental results, the kinetics of solvent oxidative and thermal degradation is estimated and included in the process model developed in Aspen Plus. Using this model, the influence of operating parameters like the oxygen concentration in the flue gas or the solvent regeneration pressure is studied. This model is a first step for a multi-objective optimization of the CO2 capture process, assessing both energy and environmental penalties of this technology. [less ▲]

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See detailOptimal conception of a post-combustion CO2 capture unit with assessment of solvent degradation
Léonard, Grégoire ULg; Toye, Dominique ULg; Heyen, Georges ULg

Poster (2013, September)

Solvent degradation may be a major drawback for the large-scale implementation of post-combustion CO2 capture due to amine consumption and emission of degradation products. A kinetics model describing ... [more ▼]

Solvent degradation may be a major drawback for the large-scale implementation of post-combustion CO2 capture due to amine consumption and emission of degradation products. A kinetics model describing solvent oxidative and thermal degradation has been developed based on experimental results. This model has been included into a global Aspen Plus model of the CO2 capture process, so that optimal operating conditions can be identified to minimize both energy and environmental impacts of the process. [less ▲]

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See detailDynamic Modeling and control of a pilot CO2 postcombustion capture plant
Léonard, Grégoire ULg; Cabeza Mogador, Bruno; Belletante, Ségolène et al

Poster (2013, June)

A dynamic model of a post-combustion capture pilot plant is developed using Aspen Plus Dynamics. An innovative process control strategy is studied for regulating the water balance of the process. A ... [more ▼]

A dynamic model of a post-combustion capture pilot plant is developed using Aspen Plus Dynamics. An innovative process control strategy is studied for regulating the water balance of the process. A washing section where the flue gas from the absorber is washed with cold water is included to the process in order to reduce the emissions of amine to the air. Control of the water balance in the solvent loop is successfully achieved by changing the washing water temperature. In previous publications regarding CO2 capture pilot plants, the regulation of the water balance always required a water make-up flow which appears here as unnecessary. Rejection of disturbances and different load reduction scenarios are tested to confirm the efficiency of this strategy. Potential operational problems of this control strategy are identified and solved. [less ▲]

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See detailDynamic modelling and control of a pilot plant for post-combustion CO2 capture
Léonard, Grégoire ULg; Cabeza Mogador, Bruno; Belletante, Ségolène et al

in Computer Aided Chemical Engineering (2013), 31

A dynamic model of a post-combustion pilot capture plant is developed using Aspen Plus Dynamics. An innovative process control strategy is studied for regulating the water balance of the process. A ... [more ▼]

A dynamic model of a post-combustion pilot capture plant is developed using Aspen Plus Dynamics. An innovative process control strategy is studied for regulating the water balance of the process. A washing section where the flue gas from the absorber is washed with cold water is included to the process in order to reduce the emissions of amine to the air. Control of the water balance in the solvent loop is successfully achieved by changing the washing water temperature. In previous publications regarding CO2 capture pilot plants, the regulation of the water balance always required a water make-up flow which appears here as unnecessary. Rejection of disturbances and different load reduction scenarios are tested to confirm the efficiency of this strategy. Potential operational problems of this control strategy are identified and solved. [less ▲]

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See detailModélisation du captage post-combustion du CO2 avec évaluation de la dégradation des solvants
Léonard, Grégoire ULg; BELLETANTE, Ségolène; Cabeza Mogador, Bruno et al

in Récents Progrès en Génie des Procédés (2013), 104

Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy ... [more ▼]

Post-combustion CO2 capture in power plants is one of the most mature technologies for a short-term and large-scale decrease of CO2 emissions while simultaneously addressing the growing global energy demand. CO2 is chemically absorbed in an amine solvent that can be regenerated at higher temperature, producing a pure CO2 stream. However, the large impact of this technology on the power plant efficiency and the environmental penalty are the main drawbacks for large-scale implementation. In this work, an innovative approach combining process modeling and evaluation of the environmental penalty due to amine degradation is presented. Based on experimental results, the kinetics of solvent oxidative and thermal degradation is estimated and included in the process model developed in Aspen Plus. Using this model, the influence of operating parameters like the oxygen concentration in the flue gas or the solvent regeneration pressure is studied. This model is a first step for a multi-objective optimization of the CO2 capture process, assessing both energy and environmental penalties of this technology. [less ▲]

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See detailCO2 CAPTURE in POWER PLANTS: Process Simulation and Solvent Degradation
Léonard, Grégoire ULg; Lepaumier, Hélène; Thielens, Marie-Laure et al

Poster (2012, November)

Presentation of the research themes studied at the University of Liège in the field of CO2 capture

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See detailCarbon nanotube synthesis by CCVD process: kinetic study on a Ni-Mo/MgO catalyst
Douven, Sigrid ULg; Pirard, Sophie ULg; Chan, Fang-Yue et al

Poster (2012, October)

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See detailSynthèse de MWNT dans un réacteur continu incliné rotatif à lit mobile par procédé CCVD
Douven, Sigrid ULg; Pirard, Sophie ULg; Chan, Fang-Yue et al

Conference (2012, October)

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See detailModélisation des grands systèmes chimiques: travaux pratiques
Gerkens, Carine; Leruth, Alexandre; Léonard, Grégoire ULg et al

Learning material (2012)

Notes de Travaux pratiques à l'attention des étudiants 1ere master ingénieur civil chimiste et sciences des matériaux

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See detailPOST-COMBUSTION CO2 CAPTURE: Global Process Simulation and Solvent Degradation
Léonard, Grégoire ULg; Lepaumier, Hélène; Blandina, Fabrice et al

Poster (2012, February)

One of the biggest upcoming challenges concerning both environmental and energy systems engineering is the control and limitation of greenhouse gas emissions due to human activity. Fossil fuels-fired ... [more ▼]

One of the biggest upcoming challenges concerning both environmental and energy systems engineering is the control and limitation of greenhouse gas emissions due to human activity. Fossil fuels-fired power plants are in this context one of the main contributors due to the large amounts of CO2 emitted. Different technologies have been developed for capturing CO2 from such power plants. This work focuses on post-combustion CO2 capture by reactive absorption into amine solvents like monoethanolamine (MEA). The main drawback of this technology is actually the high energy requirement of the process, especially for solvent regeneration. It is then highly interesting to model the capture process so that optimal operating conditions could be approached by simulation thus reducing the number of expensive experimental tests. Thanks to the simulation, it has been possible to identify the most influent process variables and to optimize their value. It was also possible to study the impact of process modifications on the global capture efficiency. The improvements studied allowed for a reduction by up to 14% of the process exergy consumption. Another major drawback of the post-combustion CO2 capture is solvent degradation, which can be due to thermal as well as oxidative mechanisms. Degradation affects the CO2 capture process since it may cause corrosion, foaming and fouling, possibly inducing a decrease of the solvent efficiency and high additional operating costs due to solvent replacement. In order to study degradation of conventional amine solvents as well as degradation of novel solvents, a degradation test rig has been built at the University of Liège in collaboration with the company Laborelec, member of the GDF SUEZ group. First results show that degradation obtained on this lab installation can be compared to degradation results observed on CO2 capture pilot installation. The final objective of this thesis is to make a link between degradation and simulation. Experimental data obtained on the degradation test rig will be implemented into the existing simulation model so that optimal operating conditions considering both process energy efficiency and solvent degradation can be determined. [less ▲]

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See detailMachine learning techniques for atmospheric pollutant monitoring
Sainlez, Matthieu ULg; Heyen, Georges ULg

Poster (2012, January 27)

Machine learning techniques are compared to predict nitrogen oxide (NOx) pollutant emission from the recovery boiler of a Kraft pulp mill. Starting from a large database of raw process data related to a ... [more ▼]

Machine learning techniques are compared to predict nitrogen oxide (NOx) pollutant emission from the recovery boiler of a Kraft pulp mill. Starting from a large database of raw process data related to a Kraft recovery boiler, we consider a regression problem in which we are trying to predict the value of a continuous variable. Generalization is done on the worst case configuration possible to make sure the model is adequate: the training period concerns stationary operations while test periods mainly focus on NOx emissions during transient operations. [less ▲]

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See detailStudy of 2-Ethanolamine degradation
Léonard, Grégoire ULg; Toye, Dominique ULg; Heyen, Georges ULg

Conference (2012, January)

One major drawback of the post-combustion CO2 capture using conventional amine solvents is solvent degradation, which can be due to thermal as well as oxidative mechanisms. Degradation affects the CO2 ... [more ▼]

One major drawback of the post-combustion CO2 capture using conventional amine solvents is solvent degradation, which can be due to thermal as well as oxidative mechanisms. Degradation affects the CO2 capture process since it may cause corrosion, foaming and fouling, possibly inducing a decrease of the solvent efficiency and high additional operating costs due to solvent replacement. In order to study degradation of conventional amine solvents as well as degradation of novel solvents, a degradation test rig has been built at the University of Liège in collaboration with the company Laborelec, member of the GDF SUEZ group. Since degradation generally occurs within a few months in real plant conditions, this equipment has been designed to allow the study of different degradation mechanisms under accelerated conditions, at high temperatures (up to 140°C) and high partial pressures in oxygen and CO2 (total pressure up to 20 bar with varying gas composition). An advantage of this degradation test rig is that it can be used in batch as well as in semi-batch mode with constant gas flow. High gas-liquid contact efficiency is also ensured thanks to a mechanical agitation system combined with gas bubbling. For a typical run, 300g of aqueous amine solution (30 wt % MEA in water) is introduced into the reactor and degraded during two weeks. The degraded solutions are then analysed using high pressure liquid chromatography (HPLC) for MEA quantification and gas chromatography with flame ionization detector (GC-FID) for the characterization of degradation products. The gas phase is analysed by Fourier Transform Infra Red spectroscopy. The final objective of this work is to implement the data obtained from experimental results on the degradation test rig into an existing simulation model that has been developed based on an existing pilot plant. [less ▲]

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See detailComparison of supervised learning techniques for atmospheric pollutant monitoring in a Kraft pulp mill
Sainlez, Matthieu ULg; Heyen, Georges ULg

in Journal of Computational & Applied Mathematics (2012)

In this paper, supervised learning techniques are compared to predict nitro- gen oxide (NOx) pollutant emission from the recovery boiler of a Kraft pulp mill. Starting from a large database of raw process ... [more ▼]

In this paper, supervised learning techniques are compared to predict nitro- gen oxide (NOx) pollutant emission from the recovery boiler of a Kraft pulp mill. Starting from a large database of raw process data related to a Kraft recovery boiler, we consider a regression problem in which we are trying to predict the value of a continuous variable. Generalization is done on the worst case configuration possible to make sure the model is adequate: the training period concerns stationary operations while test periods mainly fo- cus on NOx emissions during transient operations. This comparison involves neural network techniques (i.e., multilayer perceptron and NARX network), tree-based methods and multiple linear regression. We illustrate the potential of a dynamic neural approach compared to the others in this task. [less ▲]

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See detailLarge-scale synthesis of multi-walled carbon nanotubes in a continuous inclined mobile-bed rotating reactor by the catalytic chemical vapour deposition process using methane as carbon source
Douven, Sigrid ULg; Pirard, Sophie ULg; Chan, Fang-Yue et al

in Chemical Engineering Journal (2012)

Multi-walled carbon nanotubes (CNTs) were produced in a continuous inclined mobile-bed rotating reactor by the catalytic chemical vapour deposition of methane on a bimetallic Ni-Mo/MgO catalyst whose ... [more ▼]

Multi-walled carbon nanotubes (CNTs) were produced in a continuous inclined mobile-bed rotating reactor by the catalytic chemical vapour deposition of methane on a bimetallic Ni-Mo/MgO catalyst whose activity remains constant in the course of time. Measurements performed on the continuous reactor were validated to ensure that the installation worked correctly and that measurements were precise enough. The performance of the reactor was simulated using a model based on the chemical reactor engineering approach. Hypotheses of the model were verified, and a kinetic study was performed to obtain a kinetic rate expression and to determine the catalytic activity as a function of time. The purity level of produced CNTs depends on the desired properties of the product, so the operating conditions are linked to the purity level that is required. A minimal purity level corresponds to high carbon production, and a maximal purity level corresponds to high specific productivity. It was shown that operating conditions had to be fixed to reach a given specific productivity or a given carbon production, and the optimized operating conditions leading to those two opposite purity level objectives were established. [less ▲]

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See detailComparison of Machine Learning techniques for atmospheric pollutant monitoring in a Kraft pulp mill
Sainlez, Matthieu ULg; Heyen, Georges ULg

Conference (2011, November)

In this paper, machine learning techniques are compared to predict nitrogen oxide (NOx) pollutant emission from the recovery boiler of a Kraft pulp mill. Starting from a large database of raw process data ... [more ▼]

In this paper, machine learning techniques are compared to predict nitrogen oxide (NOx) pollutant emission from the recovery boiler of a Kraft pulp mill. Starting from a large database of raw process data related to a Kraft recovery boiler, we consider a regression problem in which we are trying to predict the value of a continuous variable. Generalization is done on the worst case configuration possible to make sure the model is adequate: the training period concerns stationary operations while test periods mainly focus on NOx emissions during transient operations. This comparison involves neural network techniques (i.e., static multilayer perceptron and dynamic NARX network), tree-based methods and multiple linear regression. We illustrate the potential of a dynamic neural approach compared to the others in this prediction task. [less ▲]

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See detailModeling post-combustion CO2 capture with amine solvents
Léonard, Grégoire ULg; Heyen, Georges ULg

Poster (2011, June)

Carbon capture and storage is a technology that can contribute to face the challenge of rising energy demand combined with a growing environmental awareness. In the present work, the CO2 capture process ... [more ▼]

Carbon capture and storage is a technology that can contribute to face the challenge of rising energy demand combined with a growing environmental awareness. In the present work, the CO2 capture process with monoethanolamine (MEA) is modeled using the simulation tool Aspen Plus. Two different modeling approaches are studied and compared: the equilibrium and the rate-based approaches. An optimization of key process parameters is performed and process modifications are studied with the objective of improving the global process energy efficiency. [less ▲]

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See detailKraft RB : recurrent neural network prediction of steam production
Sainlez, Matthieu ULg; Heyen, Georges ULg

Poster (2011, May 30)

In this study, neural networks approaches are compared for predicting the high pressure (HP) steam flow rate from a Kraft recovery boiler. We apply two types of neural networks: a static multilayer ... [more ▼]

In this study, neural networks approaches are compared for predicting the high pressure (HP) steam flow rate from a Kraft recovery boiler. We apply two types of neural networks: a static multilayer perceptron and a dynamic Elman’s recurrent neural network. Starting from a one-day database of raw process data related to the boiler, the goal is to model and predict the next 12-hours of HP steam flow production from the boiler to the steam turbine. The results illustrate the potential of the dynamic approach in this task. [less ▲]

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