Monoethanolamine Solvent Research Articles

Machine learning-driven assessment of relationship between activator properties in phase change solvent and its absorption performance for CO2 capture

Amine-based phase change solvents are recognized as an energy saving alternative to the benchmark solvent, mono-ethanolamine (MEA), for CO2 capture owing to their unique phase separation behavior and low energy penalty. However, screening of the phase change solvents is labor intensive via the experimental analysis. To address this issue, this work intends to develop a machine learning-driven assessment system to screen promising phase change solvents via exploring the relationship between activator properties and absorption performance. Based on the machine learning and quantum calculation, the relationships between 11 properties of 30 activators and 6 performance parameters were observed. Subsequently, the sensitive analysis was conducted via focusing on 5 key activator properties, such as alkalinity, hydrophobicity, molar refraction index, molar volume and the ADCH charge of N atom. Based on the proposed assessment system, 4 phase change solvents with potential excellent performance were screened, and kinetics and thermodynamics were further verified by experimental results. Among them, the regenerative heat of diethylenetriamine/N,N-Diethylethanolamine (DETA/DEEA) was around 2.44 GJ t−1, which is ∼ 34 % lower than that of benchmark MEA solvent. It is believed that the assessment system developed in this work can deepen the understanding of screening and practical application of phase change solvents.

Use of copper carbonate as corrosion inhibitor for carbon steel in post combustion carbon capture

The realisation of post-combustion CO2 capture (PCCC) at industrial scale remains limited; one challenge is the concerns around capital costs and another concern is corrosion of the system itself. Corrosion resistance and mitigation against the amine solvent monoethanolamine (MEA) was studied, using the inhibitor copper (II) carbonate basic (CC). Carbon steel (C1018) was tested in CO2 loaded, 5M aqueous MEA solution, alone and in the presence of CC, to assess the corrosivity of the solution. Immersion testing used mass loss, Fe and Cu ion concentration in solution via ICP-MS, imaging (SEM) and analytical techniques (XRD and EDX) to investigate the effect of corrosion. Generally, the use of CC improved C1018 corrosion resistance relative to C1018 alone. Even at low concentrations (0.9 mM), CC was effective in inhibiting corrosion against CO2 loaded MEA, as the observed corrosion rate was effectively zero and no dissolved Fe was detected in solution. There was no evidence of copper surface adsorption. To clarify the solution chemistry resulting in corrosion inhibition, the local chemical environment of Fe and Cu were probed by Cu and Fe K-edge X-ray Absorption Spectroscopy, respectively. The Cu K- edge HERFD-XANES spectra reveal that a Cu2+ amine complex forms, critical to understanding the structure which is promoting significant corrosion inhibition.

Life cycle assessment of potassium lysinate for biogas upgrading

Monoethanolamine solvent (MEA) is a common solvent used in biogas upgrading plant for carbon dioxide (CO2) and hydrogen sulfide (H2S) removal. However, it has some downsides such as corrosive, high toxicity, and promotes products degradation. Alternatively, amino acid-based solvents such as potassium lysinate (LysK) have been found to have good absorption performance. It is also claimed to be more environmentally friendly as it is less toxic and has a good biodegradability. However, its actual environmental impact for the application of biogas upgrading has not been quantified in a detailed manner. Therefore, in this study, the environmental impact of LysK solvent is quantified from gate to grave in terms of Global Warming Potential (GWP), Acidification Potential (AP) and Eutrophication Potential (EP) using life cycle assessment (LCA) approach. The process was simulated using process simulator, SuperPro Designer version 10 to obtain the input-output data. LysK solvent has a low heat of absorption, which could result in lower CO2 emissions during the biogas upgrading process. However, due to its energy-intensive nature, the incineration process significantly contributed to GWP, AP, and EP. There were also emissions of NOx and SO2 from the flue gas of the incinerator. The findings of this research provide some insight on the environmental impact of utilising LysK for biogas upgrading.

Impact of Solvent on the Thermal Stability of Amines.

Water-lean solvents have been proposed as a possible alternative to aqueous amine systems in postcombustion carbon capture. There is however little data available on how amine degradation is affected by different solvents. This study presents new insights on the effect of solvent on thermal degradation of alkanolamines from laboratory-scale degradation experiments. Replacing the water in aqueous monoethanolamine (MEA) solutions with organic diluents resulted in varying thermal degradation rates. Overall, all tested organic diluents (triethylene glycol, diethylene glycol, mono ethylene glycol, tetrahydrofurfuryl alcohol, N-formyl morpholine/water, and N-methyl-2-pyrrolidone) resulted in higher thermal degradation rates for loaded MEA. None of the proposed parameters, such as acid-base behavior, polarity, or relative permittivities, stood out as single contributing factors for the variation in degradation rates. The typical degradation compounds observed for an aqueous MEA solvent were also observed for MEA in various concentrations and with various organic diluents.

Techno-economic evaluation of post-combustion carbon capture based on chemical absorption for the thermal cracking furnace in ethylene manufacturing

As the core unit of an ethylene production plant, thermal cracking furnace generates a large amount of CO2 emissions. To reduce the CO2 emissions, post-combustion carbon capture based on chemical absorption using monoethanolamine (MEA) solvent is used to capture CO2 from the thermal cracking furnace. The computational fluid dynamics (CFD) method was used to simulate the operation of a 60kt/a thermal cracking furnace to obtain the flow rate and composition of the flue gas. A carbon capture plant model was developed using Aspen Plus® and validated using the pilot plant test data from Technology Centre Mongstad (TCM) in Norway. Scale-up of the capture plant model was carried out to match the flue gas flow rate of the thermal cracking furnace. Two integration cases of the carbon capture plant and the industrial thermal cracking unit were carried out. The results show that the excess heat of the gasoline fractionator can be used to provide heat for the carbon capture plant without affecting ethylene production. The economic evaluation was conducted based on the two case studies. Results show that the cost of CO2 capture can be reduced from $80.03/tonne (without heat integration) to $70.41/tonne with heat integration. When considering the impact of carbon credits on capture costs, the cost will be further reduced to $50.41/tonne.

Pilot scale assessment of a novel phase-change solvent for energy efficient post -combustion CO2 capture.

The proliferation of industrial-scale CO2 capture technologies requires improvements in existing systems. Absorption/desorption capture processes that employ phase-change solvents (PCS) are promising for energy and cost reduction. Several PCSs have been investigated at bench scale, but very few have been tested in pilot-scale plants. The novel PCS mixture S1N (N1- cyclohexylpropane-1,3-diamine)/DMCA (Dimethylcyclohexylamine) has previously exhibited desirable performance in equilibrium experiments, economic and sustainability studies. This work presents the pilot-scale evaluation of S1N/DMCA for the first time, at two different concentrations and various liquid-to-gas ratios. Experimental evidence on key performance indicators is brought forward, including absorption efficiency, cyclic capacity, distance from equilibrium and regeneration energy in comparison to benchmark solvent MEA (monoethanolamine). S1N/DMCA enables robust operation as it maintains a cyclic capacity of 0.63mol/kg at different liquid-to-gas ratios, which is about two times higher than that of MEA. It achieves operating loadings close to equilibrium, reaching 1.6mol/kg, and a regeneration energy of 2.3 GJ/tn CO2, representing 45% reduction compared to MEA.

CO2 regeneration energy requirement of carbon capture process with an enhanced waste heat recovery from stripped gas by advanced transport membrane condenser

This study proposed to build an energy efficient and reliable CO2 regeneration system, via the integration of an advanced transport membrane condenser (TMC) and principle of rich solvent-split (RS), namely the TMC-based RS system. With the monoethanolamine (MEA) solvent and a TMC module housed commercial 19-channel hydrophilic ceramic membranes, the operational stability and energy requirement of the proposed system were evaluated. With a relatively low error (i.e., ± 5%) of the overall mass balance, the proposed system exhibited excellent reliability in operation. Compared to the traditional CO2 regeneration process without the RS modification, the conventional system with only the RS modification showed 4.8% saving in the reboiler duty (kWh/kg-CO2) at the split fraction of 10%; while the TMC-based RS process showed up to 21.7% saving in the reboiler duty with 0.2 m2 membrane area at the split fraction of 30%. The energy saving corresponded to a decrease from 5.2 MJ/kg-CO2 to 3.9 MJ/kg-CO2 in terms of the calculated CO2 regeneration heat requirement. The sensitivity analysis showed that the TMC-based RS system was less susceptible to variations in operation conditions, demonstrating a low and relatively stable reboiler duty. An additional benefit of the proposed system was the reduced consumption of cooling water.

Inducing efficient proton transfer through Fe/Ni@COF to promote amine-based solvent regeneration for achieving low-cost capture of CO2 from industrial flue gas

Catalytic amine-based solvent regeneration with solid acid is a feasible option for reducing energy consumption of CO2 capture, but facing crucial challenges on designing material structures and understanding reaction mechanisms. Herein, we cover the nanoscale NiFe2O4 cluster with covalent organic frameworks (COFs), to prepare solid acid catalysts. The pristine chemical bonds of Ni(Fe)-O and Ni(Fe)-Ni(Fe) are substituted by Ni(Fe)-N and Ni(Fe)-N-Ni(Fe) by targeting the anchoring of NiFe2O4 cluster over COFs. The created coordination state stimulates the production of Brønsted acid sites. The obtained nanomaterials achieve a considerable improvement in CO2 desorption of up to 290.1 mmol/(min·g) at 88 °C for spent monoethanolamine (MEA) solvent, representing a substantial increase of 540% relative to traditional thermal desorption. Consequently, the energy consumption of MEA generation is reduced by approximately 58%. Intermediate species (HCO3−, CO32−, and RNHCOO−) and reaction pathways are established by combining operando Raman spectroscopy and ex situ 13C NMR spectrum measurements. Theoretical calculations are performed to clarify the transformation mechanism of the acid sites around Ni/Fe atoms and its intrinsic role in the adsorption equilibrium of solvent regeneration.

Environment-friendly recycling of CFRP composites via gentle solvent system at atmospheric pressure

The recovery of high-value carbon fibers from carbon fiber-reinforced polymer (CFRP) composites is essential for ensuring a sustainable future. In this work, a simple and eco-friendly approach was presented for the chemical recycling of anhydride-cured epoxy-based CFRP composites with a mixed solution of monoethanolamine (MEA) and potassium hydroxide (KOH). In this solvent catalyst system, the resin matrix was decomposed by cleaving the ester bonds. Thus, a high CFRP composite decomposition ratio of 99% was achieved at ∼160 °C within 60 min under ambient pressure. The recovered carbon fibers (CFs) had a clean surface and retained more than 95% of their original stiffness and strength. Moreover, one of the highlights of this process was that the excess MEA solvent and degraded epoxy resin (DER) were recovered from the degraded organic products (DOP) by simple distillation. The DER was reused in combination with the original epoxy resin system to prepare new resin material with good mechanical properties, forming a closed-loop chemical recycling route. The advantages of this method include facile reaction conditions, near-complete recovery of CFs and solvent, and the absence of harmful solid waste, demonstrating that this recycling process has a high degree of environmental friendliness.

Investigation of equilibrium CO2 solubility in 35 wt% aqueous 1-(2-aminoethyl) piperazine (AEP) and performance study over monoethanolamine for CO2 absorption

The present study investigates the CO2 absorption capacity of 1-2-(aminoethyl)piperazine (AEP) as a potential solvent for post combustion CO2 capture. The CO2 absorption performance has been evaluated in terms of Equilibrium CO2 solubility at varied temperature and pressure range. The CO2 solubility measurement was conducted using high pressure stirred autoclave reactor within the temperature and Pressure range of (308.15–328.15) and (2–200) kPa respectively. The equilibrium CO2 solubility data are further correlated using semi-empirical model and equilibrium based Modified Kent-Eisenberg model which shows a better agreement with the generated experimental data. In addition to this, a comprehensive parametric study was also carried out in Aspen-Plus Platform to evaluate the performance of proposed solvent over conventional solvent monoethanolamine (MEA). Influence of various important operating parameters such as flow rates of solvent and Gas medium, amine concentration, solvent inlet temperature and (L/G) ratio on the % CO2 removal was studied.

Modeling and Parametric Investigation of Rotating Packed Bed Processes for CO2 Capture and Mineralisation

Rotating Packed Beds (RPB) are receiving increased attention in CO2 capture, due to their considerably lower volume compared to conventional packed-beds and their beneficial effects on process capital costs. As a result of these advantages, RPB have also been considered as a CO2 mineralisation option for the production of precipitated calcium carbonate (PCC). In the area of CO2 capture, the few model-based investigations employ either the two-film or Higbie’s penetration theory to model the gas-liquid mass transfer as the main driving force of the systems’ operation. In the area of PCC production, there is only one model type available that is based on the two-film theory. While the latter includes the limiting assumption of linear and steady-state mass transfer within the liquid film, Higbie’s theory is considerably closer to realistic operation due to the assumption of time-dependent and non-linear, gas-to-liquid mass transfer. Considering this significant advantage, this work proposes for the first time a model for RPB-based, PCC production using Higbie’s penetration theory. The model is first developed and validated considering solvent-based CO2 capture with monoethanolamine (MEA) solvent, taking advantage of the available experimental data in published literature. The model is then adapted to PCC production to perform a parametric investigation based on various performance indicators. Results indicate that the proposed model enables improved accuracy compared to the two film theory. Higher rotation speeds and liquid flowrates enable improved mass transfer, whereas PCC production can be achieved at lower energy consumption simultaneously with high CO2 capture efficiency.

Design and cost estimation of a CO2 capture plant from cement flue gas for urea production in Nepal

This paper presents a detailed design, cost estimation and sensitivity analysis for establishing a CO2 capture plant for use in urea manufacturing in the context of Nepal. The commercially proven post combustion capture process, monoethanolamine (MEA) solvent based scrubbing, was designed with the help of Aspen Plus to determine the size of scrubbing towers, accessory equipment's and the utilities for capturing 90% of CO2 from the flue gas. The flue gas stream data was obtained from a local cement industry. Our analysis showed that absorber and stripper columns of 10 m and 7 m packing height respectively are required to capture approximately 250 Ktons/year of CO2. The columns will have packing diameters of 6 m and 4 m respectively. The total capital cost and the production cost for the plant of this scale was calculated to be $10 million and $21 million respectively. The bulk of the total production cost, $18 million per year, was the utility (electricity) cost for regenerating the solvent. The profitability of the capture plant was found to be highly sensitive to the electricity cost which presents a huge opportunity for Nepal. Based on our estimate, the total cost per kg of CO2 capture in Nepal will be about $0.086. A 30% lower electricity cost would lower the capture cost to $0.063/kg CO2. The availability of cheap hydropower electricity (lower than $0.01/kWh) makes CO2 capture based urea manufacturing process to be a viable alternative for Nepal. We hope this economic evaluation data will serve as the baseline for the policy makers to undertake a more detailed study on the carbon capture and electrolysis based urea manufacturing plant in the country.

Diamine based water‐lean CO2 solvent with extra high cyclic capacity and low viscosity

AbstractThe industrial application of emerging water‐lean solvents to CO2 capture from flue gas is challenged by their high viscosity. In this work, we report a novel water‐lean CO2 solvent which possesses lower viscosity and higher CO2 cyclic capacity than other water‐lean solvents reported in the literature. The new solvent consists of N, N‐dimethyl‐1, 2‐ethanediamine (DMEDA), physical cosolvent N‐methyl‐2‐pyrrolidone (NMP) and up to 15% water (named ENH). We evaluated the effect of the solvent composition on the viscosity, CO2 cyclic capacity and regeneration energy of ENH and compared it with the reference monoethanolamine (MEA) based solvents. It was found that ENH containing 5% H2O (ENH‐5%H2O) with a CO2 loading of 0.767 mol CO2·mol amine–1 had a viscosity of 7.603 mPa·S at 40 ˚C, which was comparable with that of traditional blended amines. Excellent cyclic capacity performance was also observed, with ENH‐5% H2O showing a 140% improvement compared to aqueous MEA. Regeneration energy of ENH‐5% H2O was estimated to be 2.418 GJ·tCO2–1 which is 36% lower than the 30 wt. % aqueous MEA solvent. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.

Comprehensive Evaluation of a Deep Eutectic Solvent Based CO2 Capture Process through Experiment and Simulation

As an emerging green and sustainable solvent, a deep eutectic solvent (DES) applied to the carbon capture process is considered to be a promising absorbent. This work aims to comprehensively evaluate the potential and effectiveness of DESs for CO2 capture. First, a hydrophobic DES, which is composed of tetrabutylammonium bromide as the hydrogen bond acceptor (HBA) and decanoic acid as the hydrogen bond donor (HBD) with a molar ratio of 1:2, was screened out from 280 DESs by the conductor-like screening models–segment activity coefficient (COSMO-SAC) model. Then, quantum chemistry methods were used to investigate the interaction mechanism between the DES and CO2. The results show that the interactions between CO2 and the DES are mainly weak hydrogen bonds and van der Waals dispersion attraction forces. Next, gas–liquid equilibrium experiments were performed to investigate the effects of temperature and pressure, the types of HBAs and HBDs, and the molar ratios of HBA to HBD on the solubility of CO2. The results show that the process of DES absorbing CO2 obeys Henry’s law and confirm the reliability of the COSMO-SAC model prediction. Finally, a rigorous rate-based model for the DES-based postcombustion CO2 capture process was simulated, and the life cycle environmental sustainability was evaluated and compared with that of the traditional solvent monoethanolamine, confirming the advantages of the negligible vapor pressure, thermal stability, and low ecological toxicity of the DES. This study provides a technical reference for applying new solvents developed in the laboratory to practical industrial processes.

Model predictive control for amine-based CO[formula omitted] capture process with advanced flash stripper

Advanced flash stripper (AFS) has been suggested as a process alternative for conventional absorption-based post-combustion carbon capture process, which can significantly reduce the solvent regeneration energy. However, such reduction is enabled through energy integration achieved by two additional heat exchangers, which can pose serious challenges to the control and operation of carbon capture processes. For complex energy-integrated processes, simple decentralized control scheme, where multiple proportional–integral–derivative (PID) controllers are employed, typically shows limited control performances. Thus, this study aims to propose an effective control structure for the carbon capture process with AFS, which can regulate the process under various dynamic scenarios involving significant changes in operational variables such as flue gas flowrate and carbon capture rate. Specifically, a dynamic model for the post-combustion carbon capture process is built in gPROMS, where 30 wt% Monoethanolamine (MEA) solvent is used in the absorber. Then, step responses of the controlled outputs with respect to the manipulated and disturbance inputs are analyzed to characterize the dynamic behavior of such process. A model predictive control (MPC) strategy is proposed on the basis of the understanding from the analysis. Finally, the closed-loop performances of the proposed control strategy and decentralized PID controllers are compared to demonstrate the effectiveness of the MPC strategy. The MPC strategy demonstrates that it can track the set-point change at least 20 min faster than the PID strategies, and stabilize the stripper section about 200 min faster.

Parametric Study on Co-Feeding of Municipal Solid Waste and Coal in an IGCC Power Plant with Pre-Combustion Carbon Capture

Municipal solid waste (MSW) is one of the top contributors in greenhouse gas (i.e. methane) emissions - particularly from landfill disposals. However, it could be a remarkable source of renewable energy. In Bangladesh, generation of municipal solid waste is at least 2.7 million tonne per year in the major cities, implying a heavy environmental burden. On the other hand, there are several coal-based power plants are in the pipeline to meet the increasing energy demand in Bangladesh with the potential of significant CO2 emission. To find a remedy to the above situation, a power plant using Integrated Gasification and Combustion Cycle (IGCC) technology with pre-combustion carbon capture is considered in this study. IGCC has the advantage of producing high quality syngas from a wide variety of feed and assists in the capture of CO2 at a lower cost while providing high electric efficiency. The power plant was simulated by commercial simulation packages (Aspen PLUS™ and Aspen HYSYS™) using MSW and bituminous coal (Indonesian) as a combined feed. With a feed rate of 1800 tonne per day, Syngas produced from an entrained flow type gasifier was then treated for CO2 removal using mono-ethanol amine (MEA) solvent after necessary shift in a high temperature shift reactor. About 91% efficiency was achieved in the shift reactor while the CO2 capture efficiency was varied for this study from 30% to 85%. Further parametric variation was studied by varying the moisture content of MSW and MSW to coal feed ratio. Through combustion of the H2 rich syngas in a gas turbine and subsequent steam cycle with reheat resulted in 125 MW of electricity at an efficiency of 28.95% while capturing 50% of the CO2 generated in the process for an MSW to Coal feed ratio of 1:1. With variation in moisture content especially during monsoon season, the plant efficiency could be affected remarkably. On the other hand, it was observed that the energy requirement varied from 6 to 8 MW for every 10% increase in CO2 capture quantity. Overall, by capturing 50% of the generated CO2, it is possible to reduce the emission of a same size ultra-supercritical coal-based power plant from about 700 kg CO2/MWh to about 360 kg of net CO2/MWh incorporating co-feeding and pre-combustion capture in an IGCC power plant.
 Chemical Engineering Research Bulletin 21(2020) 37-42

Technical and economic performance assessment of post-combustion carbon capture using piperazine for large scale natural gas combined cycle power plants through process simulation

The main challenges to the commercial deployment of the solvent-based post-combustion carbon capture technology include high energy consumption and high capital and operating costs. New solvents and alternative process configurations are being pursued to reduce the energy consumption and costs of the process. This paper investigates the technical and economic performance of the process using piperazine (PZ) solvent for a 250 MWe natural gas combined cycle power plant. Three different configurations of the process using PZ were evaluated and compared to the standard process using 30 wt% monoethanolamine (MEA) solvent. The technical performance of the process was evaluated using the rate-based model developed in Aspen Plus® V8.4 and the economic evaluation was carried out in Aspen Process Economic Analyzer®V8.4. The technical results showed that the total energy demand of the process reduces from 5.34 GJ/tCO2 using 30 wt% MEA to 3.56 GJ/tCO2 using 30 wt% PZ. The lowest energy demand of 2.76 GJ/tCO2 was achieved with the advanced flash stripper using 40 wt% PZ. The economic results show that the lowest total annual cost of M$26.58 per year and CO2 capture cost of $34.65 per tonneCO2 were obtained using the advanced flash stripper (AFS) with 40 wt% PZ. It was concluded that the 40 wt% PZ solvent would bring practical technical and economic benefits to the large-scale applications of the capture process compared to the current 30 wt% MEA solution. Therefore, this study will inspire policymakers and researchers towards the large-scale deployment of solvent-based PCC process.

A Benchmark for Compact CO2 Capture Plant Designs by Monoethanolamine Solvent Testing at Technology Centre Mongstad

Technology Centre Mongstad (TCM) is a large and flexible demonstration site for post-combustion CO2 capture. It is located next to the Equinor refinery at Mongstad (Norway) which is the source of the flue gases supplied to TCM. It has been used for testing CO2 capture with MEA solvent and a compact design, providing a benchmark for compact CO2 capture technologies.. The absorber was used with its lowest possible packing height of 12m, and only one of two water washes was used (3m height). The plant was operated with a high flue gas flow rate (67,000 Sm3/h) and 35 wt% MEA with a sensitivity down to 30 wt%. The CO2 inlet concentration was 6% mimicking some industrial exhausts, small turbines with exhaust gas recycle or modern turbines with high turbine inlet temperatures. The tests demonstrated that such a low absorber can capture more than 80% of the CO2 with only a slightly higher steam demand than conventional applications with higher packing heights of 18-24m. The low absorber gave 3.9 MJ/kg CO2 for the specific reboiler duty, while previous tests at other conditions and with higher absorbers gave 3.5-3.7. Acceptable emissions were observed, while degradation was higher than earlier TCM campaigns due to the choice of running with 35 w% MEA. Overall, a benchmark has been provided for future improved compact capture technologies.

Energy Performance Analysis of Post-combustion Carbon Capture using Piperazine for Large-scale Natural Gas Combined Cycle Power Plants

Post-combustion carbon capture (PCC) via chemical absorption has the potential to reduce CO2 emission significantly. The main challenges to this technology include the high energy consumption and high capital and operating costs. Alternative process configurations and new solvents are being pursued to reduce the energy consumption process. In this study, the rate-based model of the PCC process using piperazine (PZ) was developed in Aspen Plus® V8.4. The model was validated at pilot scale with experimental data. The model correctly predicted the CO2 capture level, rich loading and reboiler duty measured in the pilot plants. The validated model was scaled up to a PCC plant capable of processing flue gas from a 250 MWe natural gas combined cycle (NGCC) power plant. Three different configurations of the large-scale PCC process using 30-40 wt% PZ were simulated and the energy consumption was evaluated to determine which combination of configuration and solvent gives the best energy performance. The energy performance of the PCC process using PZ was also compared to the standard process using 30 wt% monoethanolamine (MEA) solvent. A regeneration energy of 4.97 GJ/tonneCO2 was obtained for the PCC process with 30 wt% MEA. Compared to the lowest regeneration energy obtained using the standard PCC process with PZ, the regeneration energy reduces by 35%, 41%, and 45% respectively for 30, 35 and 40 wt% PZ concentrations. The minimum regeneration energy of 2.41 GJ/tCO2 was achieved with the advanced flash stripper (AFS) process using 40 wt% PZ.

Results From MEA Testing at the CO <sub>2</sub> Technology Centre Mongstad. Verification of Residual Fluid Catalytic Cracker (RFCC) Baseline Results

Technology Center Mongstad (TCM) houses a pilot-scale test facility for CO2 capture solvents termed the “amine plant”, where multiple test campaigns have been performed on monoethanolamine (MEA). The third MEA test campaign (MEA-3) was conducted in June 2017 and several subsequent tests on MEA (MEA-4 and MEA-5) were performed, through October 2018. MEA-3, MEA-4, and MEA-5 have been the most significant collaborative test campaigns that the owners of TCM, TCM DA, have conducted since its inauguration in 2012. The large number of public, industrial, research, and academic participants involved in these campaigns have enriched the projects and ensured that the significant results will serve a broad audience. The main objective of these campaigns was to produce knowledge that can be used to reduce the cost as well as the technical, environmental, and financial risks for the commercial-scale deployment of post-combustion CO2 capture (PCC). This includes demonstration of a model-based control system, dynamic operation of the amine plant, investigating amine aerosol emissions, establishment of residual fluid catalytic cracker (RFCC) — a flue gas emanating from a nearby Equinor refinery that emulates coal in composition — baseline performance with MEA, and specific tests targeted at reducing CO2 avoided cost. Through the campaigns, both flue gas sources currently available to TCM were used, including the RFCC gas as well as flue gas from a nearby combined-cycle gas turbine (CCGT)-based combined-heat-and-power plant (CHP) that operates off of natural gas. The Electric Power Research Institute, Inc. (EPRI) assessed the performance of the MEA-based process using an independent verification protocol (IVP) previously developed for the CHP flue gas. The IVP provides a structured testing procedure for assessing the thermal and environmental performance of PCC processes under normal operating conditions. Based on this, methodology results were presented by Faramarzi et al. The IVP was updated for use with the RFCC as this gas contains 13–14 vol% CO2 content by volume whereas the CHP flue gas has 3.5 vol% CO2 content. Throughout the RFCC testing, TCM DA manually collected extractive samples from the depleted flue gas and product CO2 outlets sequentially. As part of the IVP, EPRI also assessed critical plant instrumentation at TCM for accuracy and precision error based on a comparative analysis done during testing operations and against calibration checks. The MEA baseline process was evaluated during thirteen individual test periods over four days in May 2018. During the tests, extractive samples were taken to measure process contaminants such as aldehydes, ketones, amines, and ammonia. Sulfur oxides and nitrogen oxides were continuously monitored using Fourier-transform infrared (FTIR) analyzers on the depleted flue gas and product CO2 streams. TCM DA has installed multiple measurements of the CO2 concentration (FTIR, non-dispersive infrared sensor, and gas chromatography) allowing comparative confirmation during the test periods. The capture rate was calculated via four methods. CO2 recovery (overall mass balance) was evaluated and the thermal performance (energy consumption) was assessed based on measured data taken during the tests. The CO2 capture rate achieved during the MEA RFCC testing was close to 90%, with steam reboiler duties of 3.43–3.51 GJ/tonne-CO2, and the CO2 gas mass balance closures were close to 100%. These data and the associated assessments, along with the results of TCM DA sampling during these tests, will be presented in this paper and will provide a new baseline case for 30 wt% MEA solvent in higher concentration flue gas capture cases. Based on this, TCM will now have two baselines covering flue gases with 3.5 vol% CO2 (Faramarzi et al.) and with 13–14 vol% CO2 (this project).