Grégoire Léonard

Dynamic modelling and control of a pilot plant for post-combustion CO2 capture

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.

Influence of process operating conditions on solvent thermal and oxidative degradation in post-combustion CO2 capture

Abstract The CO 2 post-combustion capture with amine solvents is modeled as a complex system interconnecting process energy consumption and solvent degradation and emission. Based on own experimental data, monoethanolamine degradation is included into a CO 2 capture process model. The influence of operating conditions on solvent loss is validated with pilot plant data from literature. Predicted solvent consumption rates are in better agreement with plant data than any previous work, and pathways are discussed to further refine the model. Oxidative degradation in the absorber is the largest cause of solvent loss while thermal degradation does not appear as a major concern. Using a single model, the process exergy requirement decreases by 10.8% and the solvent loss by 11.1% compared to our base case. As a result, this model provides a practical tool to simultaneously minimize the process energy requirement and the solvent consumption in post-combustion CO 2 capture plants with amine solvents.

Modeling post-combustion CO2 capture with amine solvents

Abstract 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 CO 2 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.

Assessment of Solvent Degradation within a Global Process Model of Post-Combustion CO2 Capture

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.

Design and evaluation of a high-density energy storage route with CO2 re-use, water electrolysis and methanol synthesis

Abstract The energy transition corresponding to more electricity generation from variable and decentralized renewable energy sources requires the development of electricity storage technologies ranging from seconds to seasons. The power-to-fuel process provides a way to store electricity as a liquid energy vector, leading to high energy density and cheap long-term storage at ambient conditions. In the present work, we study the power-to-methanol process combining CO 2 capture, water/CO 2 co-electrolysis and methanol synthesis. An Aspen Plus model focussing on the electrolysis and methanol synthesis sub-processes is presented. The energy conversion efficiency is improved from 40.1 to 53.0 % thanks to heat integration using the pinch method. Further works include the experimental demonstration of this technology as well as the development of control strategies for its regulation.

Dynamic simulation of a post-combustion CO2 capture pilot with assessment of solvent degradation

Abstract To predict solvent degradation in an industrial CO2 capture process and for a better understanding of the interactions between solvent degradation and performance of the capture process, an existing dynamic model of an amine based pilot plant for carbon capture has been improved and adapted at the University of Babes-Bolyai on the basis of the kinetic model of solvent oxidative degradation proposed at the University of Liege. The developed dynamic model has been used to simulate the transient behavior of the CO2 capture process with assessment of solvent degradation.

Recent Evolutions and Trends in the Use of Computer Aided Chemical Engineering for Educational Purposes at the University of Liège

Abstract The present paper addresses the evolution and perspectives in the teaching of CAPE methods in the Department of Chemical Engineering at the University of Liege. The transition that happened in the 90ies with the arrival of commercial software is highlighted, as the learning outcomes evolved from the ability of building programs to solve chemical engineering problems towards the ability to use complex commercial software and to understand their limitations. Moreover, CAPE methods were extended to non-dedicated CAPE courses, which is illustrated here by the goals and challenges of their use in courses like “Reactor Engineering” and “Life Cycle Analysis”. It was observed that students sometimes assume that CAPE softwares provide straightforward and trustworthy solutions without the need of understanding their mathematical bases and assumptions. Thus, solutions to make students aware of these limitations are proposed, including the creation of an integrated project focussing on complex multi-disciplinary issues, evidencing the need for critical input from the operator.