Post-combustion Capture Plant Research Articles

Hybrid Advanced Control Strategy for Post-Combustion Carbon Capture Plant by Integrating PI and Model-Based Approaches

Even though the energy penalties and solvent regeneration costs associated with amine-based absorption/stripping systems are important challenges, this technology remains highly recommended for post-combustion decarbonization systems given its proven capture efficacy and technical maturity. This study introduces a novel centralized and decentralized hybrid control strategy for the post-combustion carbon capture plant, aimed at mitigating main disturbances and sustaining high system performance. The strategy is rooted in a comprehensive mathematical model encompassing absorption and desorption columns, heat exchangers and a buffer tank, ensuring smooth operation and energy efficiency. The buffer tank is equipped with three control loops to finely regulate absorber inlet solvent solution parameters, preventing disturbance recirculation from the desorber. Additionally, a model-based controller, utilizing the model predictive control (MPC) algorithm, maintains a carbon capture yield of 90% and stabilizes the reboiler liquid temperature at 394.5 K by manipulating the influent flue gas to the lean solvent flowrates ratio and the heat duty of the reboiler. The hybrid MPC approach reveals efficiency in simultaneously managing targeted variables and handling complex input–output interactions. It consistently maintains the controlled variables at desired setpoints despite CO2 flue gas flow disturbances, achieving reduced settling time and low overshoot results. The hybrid control strategy, benefitting from the constraint handling ability of MPC, succeeds in keeping the carbon capture yield above the preset minimum value of 86% at all times, while the energy performance index remains below the favorable value of 3.1 MJ/kgCO2.

Solar-Assisted Carbon Capture Process Integrated with a Natural Gas Combined Cycle (NGCC) Power Plant—A Simulation-Based Study

In the realm of Natural Gas Combined Cycle (NGCC) power plants, it is crucial to prioritize the mitigation of CO2 emissions to ensure environmental sustainability. The integration of post-combustion carbon capture technologies plays a pivotal role in mitigating greenhouse gas emissions enhancing the NGCC’s environmental profile by minimizing its carbon footprint. This research paper presents a comprehensive investigation into the integration of solar thermal energy into the Besmaya Natural Gas Combined Cycle (NGCC) power plant, located in Baghdad, Iraq. Leveraging advanced process simulation and modeling techniques employing Aspen Plus software, the study aims to evaluate the performance and feasibility of augmenting the existing NGCC facility with solar assistance for post-carbon capture. The primary objective of this research is to conduct a thorough simulation of the Besmaya NGCC power plant under its current operational conditions, thereby establishing a baseline for subsequent analyses. Subsequently, a solar-assisted post-combustion capture (PCC) plant is simulated and seamlessly integrated into the existing power infrastructure. To accurately estimate solar thermal power potential at the Baghdad coordinates, the System Advisor Model (SAM) is employed. The integration of solar thermal energy into the NGCC power plant is meticulously examined, and the resulting hybrid system’s technical viability and performance metrics are rigorously evaluated. The paper contributes to the field by providing valuable insights into the technical feasibility and potential benefits of incorporating solar thermal energy into conventional natural gas power generation infrastructure, particularly in the context of the Besmaya NGCC plant in Baghdad. The power generation capacity of the plant was set at 750 MW. With this capacity, the annual CO2 generation was estimated at 2,119,318 tonnes/year which was reduced to 18,064 tonnes/year (a 99% reduction). The findings aim to inform future decisions in the pursuit of sustainable and efficient energy solutions, addressing both environmental concerns and energy security in the region.

Robust real-time optimization and parameter estimation of post-combustion CO2 capture under economic uncertainty

The operational cost of post-combustion carbon capture remains the principal factor impeding its uptake, thus real-time optimization has been proposed for economic operation. This requires that uncertainties be estimated, subjecting its solutions to estimation error. Herein, we propose uncertainty estimation and real-time optimization for post-combustion carbon capture plants. Model parameters are estimated using noisy measurements to address model uncertainty; accordingly, we deploy a low-variance scheme to address noise propagation. Our approach is implemented in a pilot-scale carbon capture plant through uncertain flue gas compositions and thermodynamic activities. The proposed method results in operating points closer to the true optima, with up to 25% improvement in economics compared to alternative operational approaches. Moreover, a robust real-time optimization strategy is proposed for cases in which model parameters and economic factors are simultaneously uncertain. The robust update strategy is deployed jointly with the low-variance estimation scheme to quantify the uncertainty in each model parameter, resulting in economic improvements and a notable reduction (80%) in the set point variability over the standard update approach. Through the schemes proposed, the carbon capture plant was able to operate at set points with high capture rates, low energy consumption, and low cost. This suggests that the proposed approach is suitable for the economic optimization of other energy and carbon capture systems.

Enhancing the post-combustion carbon dioxide carbon capture plant performance by setpoints optimization of the decentralized multi-loop and cascade control system

Enhancing the post-combustion carbon dioxide carbon capture plant performance by setpoints optimization of the decentralized multi-loop and cascade control system

Use of artificial intelligence in reducing energy costs of a post-combustion carbon capture plant

Absorption-based carbon capture (ACC) is the most mature technology for abating CO2 among different post-combustion carbon capture technologies. ACC is, however, energy-intensive and requires large heating and cooling utility consumption, resulting in high operational costs. Reliable and fast estimation of these utility consumptions would be valuable for technical and financial feasibility assessment of different ACC process designs. The objective of this study is to develop an artificial intelligence (AI) based approach that predicts these utility consumptions of different ACC process designs. For prediction of specific reboiler duty, which is the most important energy consumption of the plant and the main source of operational costs in the ACC process, the error of the AI models is between 0.4% and 3.6% for different scenarios of utilizing either limited or extensive training data. Moreover, the contribution of each process parameter to energy consumption was identified using explainable artificial intelligence. The findings of this study facilitate the energy-efficient design of ACC plants and provide a prioritized list of parameters to adjust for reducing the energy consumption of an ACC process.

Design and multi-objective optimization of a CO2 capture plant using deep eutectic solvents

The United Nation’s 2030 Agenda for Sustainable Development has called for taking of urgent action to combat climate change and its impacts, where CO2 capture processes have gained relevance for achieving emission objectives. Traditionally, monoethanolamine (MEA) is used in post-combustion capture (PCC) as a solvent because of its high absorption capacity. However, the use of amines is related to several environmental problems. In this work a novel post-combustion carbon capture plant is designed in Aspen Plus, under a sustainable design scheme considering environmental and economic indexes, using novel green liquids: deep eutectic solvent (DES) choline chloride/urea (1:2). Four case studies are considered for the most used fossil fuels in the power plant: coal, natural gas, associated gas, and biogas. This work represents a base case for multi-objective optimization of the PCC process coupled with a power plant for combustion. An optimization problem was defined considering the following objective functions: minimization of the environmental impact (EcoIndicator 99), minimization of the total solvent recovery energy (TSRE) and greenhouse gas emissions (GHGE); the economic objectives were set to minimize the total annual cost of the plant (TAC) and maximize return over investment (ROI). A metaheuristic optimization method, differential evolution with tabu list was chosen, and Pareto fronts for the objective functions were obtained for all case studies. It was found that the PCC process for coal-based power generation exhibits the best overall performance among all evaluated fuels. A comparison with a similarly optimized MEA-based carbon capture process shows that the use of DES leads to a 171.8% reduction in environmental impact when treating flue gas from a coal-based power process. To showcase the feasibility of the DES as a green solvent, an energy consumption of 6.62 MJ/kgCO2 is needed, compared with 6.40 MJ/kgCO2 for the MEA-based process.

Adaptive Robust Unit Commitment of Combined-Cycle Gas-Turbine Considering Mode-Based Modeling of Carbon Capture Plant

The power sector bears significant responsibility for achieving carbon neutrality. Low-carbon, high-flexibility generation technologies are pivotal in the generation mix of the foreseeable future. In this paper, a mixed-integer operation model of combined-cycle gas-turbine generators is developed, featuring a new mode-based modeling of post-combustion carbon capture plants. The model is applied to a day-ahead adaptive robust unit commitment problem considering wind power uncertainties. Numerical results from a case study on a modified 39-bus benchmark system demonstrate the correctness and practicality of the model. Compared to the linear model widely adopted in the literature, the proposed mode-based model achieves a 4.91% wider operating range in the net electric power output. Besides, the initial solvent ratio as a non-negligible parameter for the short-term operation of carbon capture plants, whose optimal setting leads to a wider operating range in the net electric power output of up to 21.96%.

A Modelling Study of Post-Combustion Capture Plant Process Conditions to Facilitate 95–99% CO2 Capture Levels From Gas Turbine Flue Gases

The principal purpose of this study is to examine the changes in process conditions that might be needed to achieve up to 99% capture levels in amine post-combustion capture (PCC) plants for combined cycle gas turbine (CCGT) flue gases. This information is of interest since, while 95% capture is adequate for current market and regulatory conditions, net zero fossil emissions (99% capture for a CCGT plant) will be required to deliver global climate mitigation targets and is increasingly a target for national climate policies. The conventionally-configured plant in the study is based on FEED studies carried out by Bechtel Corporation and uses MEA at 35% w/w. Performance modelling is undertaken using the Aspen Plus CCSI MEA Steady State Model. The results show that efficient operation at higher capture levels appears to be feasible with minimal adjustments to the plant configuration, provided that the absorber has a sufficient packing height and the stripper is capable of operation at pressures above 2 bar. The study primarily focuses on operation at low lean loadings (0.09–0.15 molCO2/molMEA) and correspondingly low L/G ratios (<1 by mass), the combination of which, in principle, can give a higher rich loading for a given capture level and packing height and consequently reduce energy consumption. However, for a given capture level, there is a minimum absorber packing height below which a near-optimal rich loading cannot be achieved for any lean loading and L/G ratio. For example, at a lean loading of 0.12 molCO2/molMEA, an absorber packing height of approximately 24 m is required for 99% capture with a minimal increase in specific energy requirements (3.77 GJ/tCO2 at 99% capture vs. 3.50 GJ/tCO2 at 95% capture). A stripper pressure of 2.4 bar is also found to be necessary to achieve this lean loading level without excessive energy requirements. The effect of varying lean loading at three constant rich loading levels is reported in detail, as are the effect of rich loading at constant lean loading and the effect of pressure on stripper performance and energy requirements. The study also examines the effects of cooling and intercooling at elevated capture levels. A simple analysis of break-even operating costs suggests that capture levels higher than the 95% envisaged in current United Kingdom guidance, to further reduce CO2 emissions costs for CCGT + PCC, might be attractive if carbon dioxide removal from air is the alternative.

Sustainable offshore natural gas processing with thermodynamic gas-hydrate inhibitor reclamation: Supersonic separation affords carbon capture

Dew-point adjustments and reclamation of thermodynamic gas-hydrate inhibitors injected in subsea flowlines are common operations in offshore natural gas rigs characterized by high costs, power consumption and carbon emissions. Typically, offshore plants employ triethylene-glycol absorption for water dew-point adjustment and Joule–Thomson expansion for hydrocarbon dew-point adjustment, while hydrate inhibitor reclamation is applied only on aqueous-inhibitor streams for re-concentration. To implement economically sustained post-combustion carbon capture on offshore rigs, a more efficient gas processing is necessary. This work contemplates a new process – supersonic separator inhibitor-reclamation – which recovers inhibitors from saturated raw-gas via supersonic separation with liquid-water injection additionally yielding exportable liquefied-petroleum-gas and natural gas with adjusted dew-points. This process dramatically improves profitability for thermodynamic inhibitors methanol, ethanol and monoethylene-glycol, creating an economic leverage that affords a post-combustion capture plant avoiding about 43% of carbon emissions. Even including post-combustion capture penalties, the supersonic separator inhibitor-reclamation process achieves a higher net value than the conventional gas processing without carbon capture. A multi-criteria sustainability assessment, based on quantitative metrics and qualitative aspects over all sustainability dimensions, evinces the supersonic separator inhibitor-reclamation process with carbon capture as more sustainable than the conventional counterpart for all inhibitors, whereas among the three inhibitors, the gas processing with monoethylene-glycol was ranked as the more sustainable for offshore rigs.

Towards Computational CO2 Capture and Storage Models

This review is aimed to increase knowledge on computational CO2 capture and storage models that are gradually evolving in the design and development to act as more effective carbon capture agents with acceptable toxicity and costs and complementary adjuncts to experiments for comprehending amino-CO2 reaction mechanisms. Also, the review discussed experimental research of degradation reactions of aqueous organic amines, measurements, kinetics and forecasts of amine pKₐ values and amine-CO2 equilibria. Also, the researcher comprehensively discussed the computational simulation of mechanisms of carbon capture reactions. In the contexts of experimental and computational studies, the comparative advantages of bicarbonate, carbamic acid, termolecular and zwitterion are described. Computational approaches shall gradually evolve in the design and development to act as more effective carbon capture agents with acceptable toxicity and costs and complementary adjuncts to experiments for comprehending amino-CO2 reaction mechanisms. Some of the main research findings indicate that advancements in quantum computing might help in simulating larger complex molecules such as CO2. Moreover, the simulations might discover new catalysts for CO2 capture that are more efficient and cheaper than present models. CO2 capture and storage (CCS) could minimize the CO2 emission volume by 14%. The first stride in CCS is capturing CO2. It accounts for 70% -80% of this technology total costs. Virtually, 50% of the costs to operate the post-combustion capture (PCC) plants are related to steam costs. It is thus important to acquire the best possible data to avoid unnecessary costs and overdesigns.

Cost Reduction Study for MEA based CCGT Post-Combustion CO <sub>2</sub> Capture at Technology Center Mongstad

A campaign was carried out by Technology Center Mongstad (TCM) and its owners in the amine capture plant to study various cost saving operating options relevant for combined cycle gas turbine plants. The owners chose MEA as solvent for this test because it is a well-studied solvent system with no commercial constraints regarding sharing of data. Learnings obtained from MEA studies are also expected to be of relevance for other solvent systems. During this campaign the main focus was on thermal energy optimization at different flue gas flow rates through the absorber column and MEA emissions, with target for reduced CAPEX and OPEX. During the campaign, new options such as a rich solvent bypass to stripper overhead and higher concentration of MEA (up to 38wt%) were tested. Tests were carried out to identify plant configurations and process parameters with the potential for CAPEX and OPEX reduction in a post-combustion carbon capture plant. Significant cost of CO2 avoided reductions were achieved compared to the previous TCM campaigns for MEA.

Best practices for the measurement of 2-amino-2-methyl-1-propanol, piperazine and their degradation products in amine plant emissions

We herein present the chemical-analytical setup used to measure atmospheric emissions of amines and amine degradation products from an amine-based post-combustion carbon capture plant. The emission measurements were carried out at the Technology Centre Mongstad (TCM) in Norway, in the frame of the ALIGN-CCUS campaign from September 2019 to January 2020, when the amine plant was operated with the CESAR 1 solvent. This advanced solvent is an aqueous solution of 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ). Four chemical-analytical techniques were deployed for characterizing emission of AMP, PZ and their degradation products: online Fourier Transform Infrared (FTIR) Spectroscopy, online Proton-Transfer-Reaction Time-of-Flight Mass Spectrometry (PTR-TOF-MS), online Proton-Transfer-Reaction Quadrupole Mass Spectrometry (PTR-QMS), as well as manual impinger sampling followed by offline Ion Chromatography Mass Spectrometry (IC-MS) analysis. AMP was detected by all four methods, with the results being in reasonably good agreement. PZ was detected by PTR-TOF-MS, PTR-QMS and IC-MS, but because of the low emission levels (single-digit ppb) the latter two methods suffered from a positive bias (due to an interfering compound) and a large measurement uncertainty, respectively. 17 amine degradation products were only detected by the PTR-ToF-MS analyzer. We present exemplary results from the emission measurements carried out during the ALIGN-CCUS 2019-2020 campaign and share some of the lessons learned from this exercise.

Full-scale FEED Study for Retrofitting the Prairie State Generating Station with an 816 MWe Capture Plant using Mitsubishi Heavy Industries Engineering Post-Combustion CO2 Capture Technology

This front-end engineering and design (FEED) study is for a carbon dioxide (CO2) capture system for Unit #2 (816 MW) at the Prairie State Generating Company’s (PSGC) Energy Campus in Marissa, IL. The capture technology used is the Advanced KM CDR Process™ from Mitsubishi Heavy Industries (MHI). The project will be the largest post-combustion capture plant in the world. In addition, it will incorporate advancements in the technology including lessons learned from past projects and a new proprietary solvent. The overall business model being developed by PSGC focuses on the generation of 45Q tax credits as a result of sequestering the captured CO2. Because the Prairie Research Institute (PRI) within the University of Illinois at Urbana-Champaign (UIUC) leads both this capture effort and the storage effort, there is close coordination and integration between the capture and storage efforts. This integration is vital to achieving the desired business targets for the project.

Analysis for a solar stripper design for carbon capture under transient conditions

This paper presents an advanced thermodynamic analysis to design a solar stripper (So-St) field to replace the conventional desorption unit in a post-combustion carbon capture (PCC) plant. By eliminating the large, complex, and costly stripper, a solar collector field (SCF) consisting of a number of So-St arrays is sized to directly release the CO2 gas from the rich solvent under transient conditions. In this study, a design protocol has been developed to address the key design challenges for the evolving two-phase flow in the solar receiver tube analysing the instantaneous flow regime, pressure drop, and vapour molar fraction (VMF) to enhance the heat transfer. This design protocol optimizes the physical properties of the So-St components and eventually leads to the whole So-St field sizing based on the nominal capture capacity. A case-study is demonstrated to capture 1.5M tonneCO2/y from a representative 660 MWe coal-fired power plant in Sydney/Australia. It is found that 22 rich solvent loops that each consists of an array of 6 parallel So-St modules, where each module consists of 6 segments in series is needed. The length/diameter of these So-St segments/modules are optimized for this case-study, and the design procedures are clarified and simplified which can be easily applied for other case-studies. Techno-economic validation of this novel So-St technology is an essential step-forward to fully solarize and autonomies carbon capture industry.

Theoretical comparison between post-combustion carbon capture technology and the use of blue and green H2 in existing natural gas combined cycles as CO2 mitigation strategies: A study under the context of mexican clean energy regulation

The objective of this work is to compare the theoretical implementation of three strategies for reducing CO2 emissions in existing natural gas combined cycles (NGCC) under the context of the Mexican clean energy regulation, namely: NGCC with post-combustion carbon capture plant (CCS); NGCC fueled with blends of natural gas and blue H2 (bH2) or green H2 (gH2). These options were analysed from the point of view of the end users in meeting the National goals in clean electricity generation during the period of 2020–2050. A techno-economic analysis was performed by considering different variables, such as clean energy certificate price, fuel costs, capital expenditure, operating cost and capacity factor plant. In general, the CCS shows a better economic performance than bH2 and gH2 cases for reducing carbon emissions in existing NGCCs. In a low natural gas price scenario ($1/MMBTU), the gH2 case is economically attractive from gH2 cost equal to or less than $ 0.9 per kg. Finally, it is found that under the current Mexican regulatory framework is not possible the incorporation of any of the technologies mentioned above, in which case, this regulation needs to be deeply amended in order to define new technical and administrative criteria for promoting the market entry of these technologies in the country.

Integration of Post-Combustion Capture and Reinjection Plant to Power Generation Cycle Using CO<sub>2</sub>-Rich Natural Gas in Offshore Oil and Gas Installation

The use of CO2-rich natural gas (%CO2 ≈ 20%mol) for power generation in offshore hubs results in simpler upgrade process, while imposes an extra challenge to mitigate emissions. Power generation via combined cycle configurations and post-combustion capture with CO2 reinjection are investigated for carbon-footprint reduction, while increasing gas export and oil production, respectively. The processes are simulated using Aspen HYSYS software and compared to currently installed simple cycle configuration in terms of footprint, weight, power, efficiency and CO2 emissions. The combined cycle including two gas turbines and one single-pressure steam cycle (CC 2:1:1) results in the most favorable power system, having 53% efficiency, 476.8 gCO2/kWh emissions and similar dimensions compared to the simple cycle. The integration of a post-combustion capture sending the CO2 for enhanced oil recovery results in 241 gCO2/kWh for the CC 2:1:1 and 251 gCO2/kWh for the simple cycle, without great impacts in total efficiency. The CC 2:1:1 with post-combustion capture presents higher net efficiency, lower dimensions and greater economic advantages, enabling emissions reduction without having significant impacts on the power generation.

Solvent Recovery System for a CO2-MEA Reactive Absorption-Stripping Plant

The solvent recovery section from the exhaust gas represents an important auxiliary part for an industrial CO2 post-combustion capture plant by the reactive absorption-stripping process. In this work, a partial condenser and a water-wash section configuration were designed to reach 1 ppm of solvent in the exhaust gas, and compared using the Total Annual Cost (TAC) as economic index. Both the configurations ensured the required recovery performance. The results highlighted that the partial condenser alternative is more convenient in terms of capital annualized costs and water make-up, but at the same time it is strongly penalized by the high operating costs for the cooling water. Therefore, the configuration in which the absorber is equipped with the water-wash section resulted the option with the minimum TAC.

Exergy Analysis and Evaluation of the Different Flowsheeting Configurations for CO2 Capture Plant Using 2-Amino-2-Methyl-1-Propanol (AMP)

This paper presents steady-state simulation and exergy analysis of the 2-amino-2-methyl-1-propanol (AMP)-based post-combustion capture (PCC) plant. Exergy analysis provides the identification of the location, sources of thermodynamic inefficiencies, and magnitude in a thermal system. Furthermore, thermodynamic analysis of different configurations of the process helps to identify opportunities for reducing the steam requirements for each of the configurations. Exergy analysis performed for the AMP-based plant and the different configurations revealed that the rich split with intercooling configuration gave the highest exergy efficiency of 73.6%, while that of the intercooling and the reference AMP-based plant were 57.3% and 55.8% respectively. Thus, exergy analysis of flowsheeting configurations can lead to significant improvements in plant performance and lead to cost reduction for amine-based CO2 capture technologies.

Techno-economic analysis of solar-assisted post-combustion carbon capture to a pilot cogeneration system in Mexico

This research evaluates the integration of solar-assisted post-combustion carbon capture into an experimental cogeneration system. A cogeneration system modelled in Thermoflex 25® that includes a 200 kW Capstone microturbine coupled with a thermal oil recovery system was installed at the National Institute of Electricity and Clean Energies (INEEL). Three optimized systems were considered for the economic analysis, namely: a microturbine cogeneration system (COGEN), a microturbine cogeneration system with post-combustion carbon capture plant (COGEN-CCS) and a microturbine cogeneration system with solar-assisted post-combustion carbon capture (COGEN-CCS + SOLAR). The cogeneration system was modelled using Natural Gas (NG) as fuel, applying characteristics typical of Mexico, to obtain the composition of exhaust gas (EG), and thus simulate the CO2 capture system in Aspen Hysys V8.6® using monoethanolamine (MEA) as solvent. Results show that the implementation of CCS results in a sizeable increase in the Levelized Cost Of Electricity (LCOE) (approximately 86%) with near-zero emissions and without the possibility of supplying energy to the process. In addition COGEN-CCS + SOLAR improves overall system performance. CO2 emissions per kilowatt increased by 0.2% with regard to COGEN-CCS, while the LCOE increased by 230% compared to the COGEN case, with near-zero emissions. The use of solar energy would help increase the cogeneration efficiency when coupled with CO2 capture.

A compact and easy-to-use mass spectrometer for online monitoring of amines in the flue gas of a post-combustion carbon capture plant

We herein report on the adaptation and deployment of a compact and easy-to-use mass spectrometer for online monitoring of amines in industrial flue gas at ppb to ppm levels. The use of ammonia as a source gas in proton-transfer-reaction mass spectrometry (PTR-MS) greatly simplifies the detection of amines, making it possible to use a low-end commercial instrument version (PTR-QMS 300) for the measurements. We characterized the analytical performance of the instrument (sensitivity, limit of detection, precision, matrix effects) for nine solvent amines (monoethanolamine, dimethylaminoethanol, aminomethylpropanol, methyldiethanolamine, diglycolamine, piperazine, aminoethylpiperazine, methylpiperazine, N-(2-hydroxyethyl)piperazine) and three degradation amines (methylamine, dimethylamine, trimethylamine). The new analyzer was tested and validated in side-by-side measurements with established emission monitoring techniques at the Technology Centre Mongstad (TCM) in Norway. After validation, the instrument was permanently installed on top of the absorber tower to deliver real-time amine emission data to the plant information management system.