IR monitoring of absorbent composition and degradation during pilot plant operation
- Authors: Puxty, Graeme , Bennett, Robert , Conway, Will , Webster-Gardiner, Mike , Yang, Qi , Pearson, Pauline , Cottrell, Aaron , Huang, Sanger , Feron, Paul , Reynolds, Alicia , Verheyen, Vincent
- Date: 2020
- Type: Text , Journal article
- Relation: Industrial and Engineering Chemistry Research Vol. 59, no. 15 (2020), p. 7080-7086
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- Description: The monitoring of the absorbent during the operation of CO2 separation processes is a necessary and challenging task. The most common absorbent used is an aqueous amine solution. Traditional approaches to analysis such as titration and chromatography are time-consuming and only provide limited information. This hinders the ability of process operators to rapidly respond to changes in operating conditions. In this work, a combination of infrared (IR) spectroscopy and principle component regression (PCR) analyses have been demonstrated as a rapid and reliable technique to determine the composition of an absorbent during a pilot plant campaign at a brown coal power station. The concentration of amine, a degradation product, CO2, and water was monitored throughout the campaign by a method that provided results in minutes. The results were verified by independent sample analysis using acid-base titration, high-performance liquid chromatography (HPLC), and 13C NMR spectroscopy. It was necessary to use spectral windowing when building the IR-PCR model, but this resulted in a robust and reliable method that has been demonstrated to work in a real-world process environment. © 2019 American Chemical Society.
- Description: The authors wish to acknowledge the financial assistance provided by the Brown Coal Innovation Australia, Ltd., a private member-based company with funding contracts through the Australian National Low Emissions Coal Research and Development, Ltd. (ANLEC R&D) and the Victorian State Government. The work described here was made possible through the PICA project, a collaboration between AGL Loy Yang, IHI, and CSIRO that aims to advance post-combustion CO 2 -capture technology in Australia.
Simulation of an SO2 tolerant amine based post-combustion CO2 capture process
- Authors: Cousins, Ashleigh , Puxty, Graeme , Pearson, Pauline , Weiland, Ralph , Garg, Bharti , Li, Kangkang , Verheyen, Vincent , Feron, Paul
- Date: 2018
- Type: Text , Journal article
- Relation: Chemical Engineering Transactions Vol. 69, no. (2018), p. 817-822
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- Description: Removal of multiple contaminants from flue gas streams in a single process step offers the potential to lower the cost of emissions reduction technologies. An example is the CS-Cap process, developed by CSIRO, which removes both the SO2 and CO2 from combustion flue gases. In order to further develop this process, a rate based simulation is required of not only the CO2 capture section, but also the absorption of SO2 into aqueous amine absorbents. ProTreat® simulation software was used to simulate CSIRO's Loy Yang CO2 capture pilot plant. This pilot plant has previously been used for proof-of-concept operation of the CS-Cap process. The model simulates various scenarios and flue gas conditions to determine the effect on the operating requirements of the SO2 capture stage. It reveals that the recirculating absorbent flow rates required in the SO2 capture loop are of similar magnitude to those required in the CO2 capture stage. Manipulating the operating parameters of the SO2 capture section will affect the properties, particularly sulfate concentration, of the slip stream sent for disposal/treatment. This could potentially allow the properties of the waste stream to be tailored for the particular downstream treatment used. In addition, condensation of water from the inlet flue gas stream is identified as an issue requiring further investigation. © Copyright 2018, AIDIC Servizi S.r.l.
Further developments in dynamic modelling of CO2 capture from flue gas
- Authors: Dickinson, Jillian , Puxty, Graeme , Percy, Andrew , Verheyen, Vincent
- Date: 2015
- Type: Text , Conference paper
- Relation: 8th Vienna International Conference on Mathematical Modelling: MATHMOD 2015 p. 1-6
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- Description: Mathematical modelling of CO2 capture from industrial flue gas by absorption into amine solutions such as monoethanolamine (MEA) has been undertaken for decades and steady state, rate-based and dynamic models have been constructed to predict the changes in the process. Recently, dynamic models have been used to predict the effect that physical operational changes have on the absorption process. As more is learnt about the chemistry of MEA and CO2 it becomes evident that the absorption system is losing available MEA, by degradation and by vaporization into the gaseous phase. This paper describes a dynamic model of the absorber column that can be used to predict the reduction of available MEA, the loss of MEA to the atmosphere, and the build-up of heat stable salts. The proposed mathematical model consists of a system of partial differential equations to represent the change of each component with height of the column and with time. It has been validated with data from a pilot capture plant located at the brown coal fired Loy Yang power station in Australia.
Experimental evaluation of methods for reclaiming sulfur loaded amine absorbents
- Authors: Garg, Bharti , Pearson, Pauline , Cousins, Ashleigh , Verheyen, Vincent , Puxty, Graeme , Feron, Paul
- Date: 2018
- Type: Text , Conference proceedings , Conference paper
- Relation: 14th Greenhouse Gas Control Technologies Conference (GHGT-14); Melbourne, Australia; 21st-26th October 2018 p. 1-8
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- Description: Sulfur dioxide (SO2) is a major flue gas contaminant that has a direct effect on the performance of amine-based carbon dioxide capture units operating on power plant flue gases. In many countries, flue gas desulfurisation (FGD) is an essential upstream requirement to CO2 capture systems, thereby increasing the overall operational and capital cost of the capture system. In Australia, the efficacy of CO2 capture may be compromised by the accumulation of SO2 in the absorption solvent. CSIRO’s CS-Cap process is designed to capture of both these acidic gases in one absorption column, thereby eliminating the need for a separate FGD unit which could potentially save millions of dollars. Previous research at CSIRO’s post-combustion capture pilot plant at Loy Yang power station has shown that mono-ethanolamine (MEA) solvent absorbs both CO2 and SO2, resulting in a spent amine absorbent rich in sulfates. Further development of the CS-Cap concept requires a deeper understanding of the properties of the sulfate-rich absorbent and the conditions under which it can be effectively regenerated. In the present study, thermal reclamation and reactive crystallisation processes were investigated, allowing the parameters affecting the regeneration of sulfate-loaded amine to be identified. It was found that amine losses were considerably higher in thermal reclamation than in reactive precipitation. During thermal reclamation, vacuum conditions were more effective than atmospheric, and pH of the initial solution played a significant role in recovery of MEA from the sulfate-rich absorbent. Reactive crystallisation could be effectively accomplished with the addition of KOH. An advantage of this process was that high purity K2SO4 crystals (~99%) were formed, despite the presence of degradation products in the solvent.
Simulating combined SO2 and CO2 capture from combustion flue gas
- Authors: Verheyen, Vincent , Cousins, Ashleigh , Pearson, Pauline , Puxty, Graeme , Jiang, Kaiqi , Garg, Bharti , Zhai, Rongrong , Ott, Petro , Feron, Paul
- Date: 2019
- Type: Text , Journal article
- Relation: Greenhouse Gases : Science and Technology Vol. 9, no. 6 (2019), p. 1087-1095
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- Description: The requirement to pre‐treat flue gas prior to the CO2 capture step is an economic challenge when using aqueous amine absorbents for capturing CO2 from coal‐fired power station flue gases. A potentially lower cost alternative is to combine the capture of both CO2 and SO2 from the flue gas into a single process, removing the requirement for the desulfurization pre‐treatment step. The CSIRO's CS‐Cap process uses a single aqueous amine absorbent to capture both of these acid gases from flue gas streams. This paper covers the initial simulation of this process applied to both brown and black coal flue gases. Removal of absorbed SO2 is achieved via reactive crystallization. This is simulated here using a ‘black box’ process, resulting in a K2SO4 product. Different operating conditions have been evaluated that increase the sulfate concentration of the absorbent in the SO2 capture section of the process, which is expected to increase the efficiency of the reactive crystallization step. This paper provides information on the absorption of SO2 into the amine solution, and heat and mass balances for the wider process. This information will be required for further detailed simulation of the reactive crystallization step, and economic evaluation of the CS‐Cap process. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.
Oxidative degradation of amine absorbents in carbon capture systems – A dynamic modelling approach
- Authors: Dickinson, Jillian , Percy, Andrew , Puxty, Graeme , Verheyen, Vincent
- Date: 2016
- Type: Text , Journal article
- Relation: International Journal of Greenhouse Gas Control Vol. 53, no. (2016), p. 391-400
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- Description: Fossil fuels are used widely for energy production and are likely to continue to play a major role world wide for many years to come. Much work has been done on the technology for capturing CO2 from gaseous industrial effluent. For large-scale applications like coal or natural gas-fired power plants, using amine solvents to capture post-combustion CO2 is the most mature CO2 capture technology. This technique can be used to retrofit existing plants by treating the flue gas after combustion. This paper details a dynamic mathematical model for the absorber column constructed from first principles. The loss of MEA through oxidative degradation has been quantified here for the first time and this is currently not possible using commercial packages. Reaction rate kinetics have been employed to predict the accumulation of oxidation products which is limited by the incomplete knowledge of the dominant reactions between O2 and MEA. When research has produced more detailed information about the products formed during this oxidation, it can be inserted easily into the model. Validation has been performed using data from the CSIRO PCC pilot plant at AGL Loy Yang. A limited parametric study of the impact of operating conditions on oxidation was performed.