Absorption Column Research Articles

A detailed look at the thermal and nonthermal X-ray emission from the Vela supernova remnant with SRG/eROSITA

Context. The Vela supernova remnant (SNR) is one of the most nearby and extended objects in the X-ray sky. It constitutes a unique laboratory for studying the thermal and nonthermal X-ray emission from an evolved SNR and its central plerion at an unprecedented level of detail. Aims. Our goal is to characterize the hot ejecta and shocked interstellar medium (ISM) associated with the Vela SNR, as well as the synchrotron-emitting relativistic electrons injected into the ambient medium by the central pulsar. To achieve this, we analyzed the dataset of Vela acquired by SRG/eROSITA during its first four all-sky surveys. Methods. We present and analyze the energy-dependent morphology of Vela using X-ray images extracted in multiple energy bands. A quantitative view of the physical parameters affecting the observed thermal and nonthermal emission is obtained by performing spatially resolved X-ray spectroscopy of over 500 independent regions using multicomponent spectral models. Results. Imaging demonstrates that the X-ray emission of the Vela SNR consists of at least three morphologically and energetically distinct components, with shell-like structures dominating below 0.6 keV, radial outward-directed features becoming apparent at medium energies, and the pulsar wind nebula (PWN) dominating the hard emission above 1.4 keV. Our spectroscopy reveals a highly structured distribution of X-ray absorption column densities, which intriguingly appears to lack any correlation with optical extinction measurements, possibly due to dust destruction or a clumpy ISM. The shock-heated plasma in Vela is found to be comparatively cool, with a median temperature of 0.19 keV, but exhibits several, often ejecta-rich, warmer regions. Within the observed ejecta clumps, we find an unexpectedly high concentration of neon and magnesium relative to oxygen, when compared to nucleosynthetic predictions. This includes the bright “shrapnel D”, in which we can separate shocked ISM in the soft bow-shock from a hot, ejecta-rich clump at its apex, based on the new data. Finally, we find an extremely extended, smoothly decreasing distribution of synchrotron emission from the PWN, which extends up to three degrees (14 pc) from the pulsar. The integrated X-ray luminosity of the PWN in the 0.5–8.0 keV energy band corresponds to 1.5 × 10−3 of the pulsar’s present-day spin-down power. The extended PWN emission likely traces the diffusion of a high-energy electron population in an ISM-level magnetic field, which requires the existence of a TeV counterpart powered by inverse Compton radiation.

Carbonic anhydrase textile structured packing for efficient CO2 absorption in methyldiethanolamine solvent

AbstractCarbonic anhydrase (CA) is an attractive biodegradable catalyst for CO2 absorption in solvent‐based CO2 capture. However, maintaining the stability of CA as a homogeneous component of the solvents is a challenge. Solvent regeneration temperature typically exceeds the enzyme thermal tolerance, which leads to CA deactivation. To reduce the need for frequent CA replenishment and to avoid inactive CA accumulation in the solvent, this work shows the benefits of an immobilization strategy where CA is fixed in a second‐generation design of textile structured packing (CATSP‐2) modules. The enzyme‐immobilized packing showed 1.5 times better performance in CO2 separation compared with traditional structured packing with a corresponding increased CO2 loading in the rich solvent. The modules exhibited good CA activity retention of ~80% during the tests without any CA replenishment. Applying CATSP‐2 could potentially decrease the packing height and absorber column size for a lower cost per amount of CO2 captured.

Machine learning based modelling and optimization of post-combustion carbon capture process using MEA supporting carbon neutrality

The role of carbon capture technology using monoethanolamine (MEA) is critical for achieving the carbon-neutrality goal. However, maintaining the efficient operation of the post-combustion carbon capture is challenging considering the hyperdimensional design space and nonlinear characteristics of the process. In this work, CO2 capture level from the flue gas in the absorption column is investigated for the post-combustion carbon capture process using MEA. Artificial neural network (ANN) and support vector machine (SVM) models are constructed to model CO2 capture level under extensive hyperparameters tuning. The comparative performance analysis based on external validation test confirmed the superior modelling and generalization ability of ANN for the carbon capture process. Later, partial derivative-based sensitivity analysis is carried out and it is the found that absorbent-based input variables like lean solvent temperature and lean solvent flow rate are the two most significant input variables on CO2 capture level in the absorption column. The optimization problem with the ANN model embedded in the nonlinear programming-based optimization environment is solved under different operating scenarios to determine the optimum operating ranges for the input variables corresponding to the maximum CO2 capture level. This research presents the optimum operating conditions for CO2 removal from the flue gas for the post-combustion carbon capture process using MEA that contributes to achieving the carbon neutrality goal.

Influence of free ammonia extraction in methane production from human urine

ABSTRACT Human urine has a high chemical oxygen demand (COD) content which makes anaerobic treatments potentially appropriate for the management of yellow waters, allowing for energy recovery. However, its high N content makes this treatment challenging. The present work studied the viability of performing an anaerobic digestion process for COD valorization on a real (not synthetic) urine stream at laboratory scale. To deal with nitrogen inhibition, two different ammonia extraction systems were proposed and tested. With them, a proper evolution of acidogenesis and methanogenesis was observed. Nitrogen was recovered in the form of ammonium sulphate, which could be used for agriculture, in two different ways: ammonia extraction from the urine stream before feeding the reactor and in situ extraction in the reactor. The first method, which proved to be a better strategy consisted in a desorption process (NaOH addition, air bubbling and acid (H2SO4) absorption column, HCl for final pH adjustment) whereas the in situ extraction in the reactor consisted of an acid (H2SO4) absorption column installed in the biogas recycling line of both reactors. Stable methane production over 220 mL/g COD was achieved and methane content in the biogas was stable around 71%.

Study of axial dispersion on several modern structured and random packings

The study investigates the phenomenon of axial dispersion in a packed absorption column, which is known to reduce the efficiency of separation equipment by reducing the mass transfer driving force. The aim of the study is to determine the Bodenstein number, which represents axial dispersion, for five types of modern packings used in the column. The packings used in the study were random packings (NeXRing0.7 and NeXRing1.2) and structured packings (MellaPak350Y, 452Y, and 500Y). The data obtained from dynamic experiments in the form of a response to a step change in tracer substance concentration were compared to a diffusion-type differential equation, which was solved with boundary conditions for a closed system. By measuring the responses at two different packed bed heights and using convolution, the influence of the end effects was eliminated. The lowest axial dispersion was obtained for M452Y, and it is almost twice as low as for M250Y. It was found that the values of the Bodenstein number for standard series of Mellapak type packing (M250Y, M350Y and M500Y) have comparable axial dispersion, especially at low liquid rates. The axial dispersion obtained for random packings is generally higher compared to structured packings. However, compared to other random packings such as Pall rings (25 mm) and Intalox saddles (25 mm), NXR0.7 and NXR1.2 exhibit up to a two-fold reduction in axial dispersion.

Analysis of Absorber Packed Height for Power Plants with Post-Combustion CO2 Capture

The electricity generation process from fossil fuels is one of the sources of CO2 emissions. The post-combustion CO2 capture is an alternative to minimize emissions. The packed absorption column is the first unit of the CO2 capture process. In this study, the values of the process parameters were established to reduce the absorber-packed height using a simulator developed in this work. The simulator was validated using measurements in a laboratory-scale absorption unit; simulations were carried out with the same operating conditions as measurements and two different fuels were treated; coal and natural gas. A combined-cycle power plant in Mexico was simulated, with the objective of evaluating the main parameters in the absorption process and required dimensions of the packed absorption column required to carry out the capture of CO2 in the power plant. From the result of the simulations, three columns treatment with 3 m diameter and 7 m height were established to remove 99% of the CO2 of the flue gases with 20 wt.% of MEA composition using Mellapak 500Y structured packaging.

Thermoeconomic and life cycle assessments for a trigeneration system: A case study

ABSTRACT The current need to diversify the global energy matrix implies introducing renewable energy sources and evaluating commercially available solutions. This study assesses a trigeneration system from thermoeconomic and environmental viewpoints, employing the Theory of Exergy Cost and Life Cycle Assessment. The location of the theoretical study case is the state of Pernambuco, Northeast Brazil. The trigeneration system operates on biogas and is comprised of four subsystems: biogas purification, molted carbon fuel cell, combined cycle, and absorption refrigeration system. The energy services produced are electricity, heat (hot water), and cooling. The results of the thermoeconomic analysis revealed that the energy system requires an electricity tariff of at least US$ 106.76/MWh to generate revenue due to the high costs associated with the purchase of biogas and capital costs of the equipment for biogas purification and fuel cell. The life cycle assessment identified that the biogas purification step presented the highest environmental impacts due to the material composition of the absorption and regeneration columns, which is interesting as this is the most critical step of the process. LCA results indicate that although methane is a vital energy vector for energy transition, further studies are required on the technical and environmental aspects of its use in energy systems.

Automated detection of loading and flooding points in packed columns

Predictive correlations for packed distillation and absorption columns usually cannot account for changes in operating limits due to phenomena such as fouling. A method for detection of loading and flooding points even under altered operating conditions would therefore be highly desirable. In this work, a new approach for real-time detection of packed column loading and flooding points is introduced. The method utilises Fourier analysis of pressure drop data. Pressure drop fluctuations occurring even under steady-state conditions are sampled and treated with Fast Fourier transform (FFT) to derive the corresponding frequency spectra. Results of examinations with three structured packings (RSP 250Y, RMP N 250X, RMP N 250Y) conducted at three liquid loads each show that operating regions (below loading point, loading point, loading region, flooding point) can be identified from the obtained frequency spectra. Starting at the loading point, certain amplitudes within the spectra grow and increase up to the flooding point. This behavior is consistent for all examined packings. The results from this study suggest that the proposed approach could support column operation as an additional monitoring tool that is low in cost and not reliant on additional measurements besides pressure drop.

Process design for the recovery of waste refrigerants using deep eutectic solvents

The environmental impact on climate change of fluorinated gases (F-gases), used mainly in refrigeration applications, is boosting the search of new recovery processes that would allow their reuse in a circular economy framework. Deep eutectic solvents (DESs) have been recently proposed as alternative absorbents in separation processes because they present several advantages, such as lower price and toxicity, in comparison with other traditional absorbents such as ionic liquids. In this work, the gas solubility of four common F-gases in different choline chloride (ChCl)-based DESs has been studied. In general, the observed gas solubility followed the next trend with the studied DESs: R-32 >R-134a>R-125 >R-143a. The affinity of the DESs for the studied F-gases was higher for ChCl:EG (1:3) than for ChCl:Gly (1:3) (10% H2O). The DESs showed good ideal selectivity for the separation of binary mixtures containing the studied F-gases. A separation process for R-410A (a 50% (w/w) mixture of R-32 and R-125) using two absorption columns was proposed and simulated with Aspen Plus using experimental data. It was found that the DESs were valid to separate R-125 with high purity (>98% w/w) and that in the case of ChCl:Gly (1:3) (10% H2O) it was possible to be recovered with high purity (>98%) and recovery (>98%) both F-gases. This work represents a step forward in the study of alternative absorbents, such as DESs, for the separation of commercial refrigerants (F-gases mixtures) for its further reuse in a circular economy context.

Observing the onset of the accretion wake in Vela X-1

High-mass X-ray binaries (HMXBs) offer a unique opportunity to investigate accretion onto compact objects and the wind structure in massive stars. A key source for such studies is the bright neutron star HMXB Vela X-1 whose convenient physical and orbital parameters facilitate analyses and in particular enable studies of the wind structure in HMXBs. Here, we analyse simultaneous XMM-Newton and NuSTAR observations at ϕorb ≈ 0.36–0.52 and perform time-resolved spectral analysis down to the pulse period of the neutron star based on our previous NuSTAR-only results. For the first time, we are able to trace the onset of the wakes in a broad 0.5–78 keV range with a high-time resolution of ~283 s and compare our results with theoretical predictions. We observe a clear rise in the absorption column density of the stellar wind NH,1 starting at orbital phase ~0.44, corresponding to the wake structure entering our line of sight towards the neutron star, together with local extrema throughout the observation, which are possibly associated with clumps or other structures in the wind. Periods of high absorption reveal the presence of multiple fluorescent emission lines of highly ionised species, mainly in the soft-X-ray band between 0.5 and 4 keV, indicating photoionisation of the wind.

Mobile pilot plant for CO2 capture in biogas upgrading using 30 wt% MEA

This study utilizes a new mobile pilot plant to capture CO2 from real biogas with 30 wt% monoethanolamine (MEA). The pilot plant is described in detail and validated by data reconciliation showing that the pilot plant produces reliable steady state data. It is demonstrated that the pilot plant can upgrade 32 kg biogas per hour by capturing 20 kg CO2 per hour. Further, the pilot plant can achieve below 2.5 mol% CO2 in the methane product at a specific reboiler duty of 3.74 GJ per ton of CO2. The absorber column was found to be operated close to pinch conditions as temperatures reached above 90 °C giving a potential for process optimization and heat integration.

Dynamic Modeling Assessment of CO2 Capture Process Using Aqueous Ammonia

In the pursuit of addressing climate change and achieving sustainable development, this study presents a comprehensive and intricate mathematical model that provides valuable insights into the process of carbon dioxide capture using ammonia aqueous solutions as solvents. The ability of the model to accurately describe the process under consideration is supported by the validation results. Specifically, the validation process involves the examination of four parameters over the height of the absorption column. The results demonstrate a strong correlation as the model predicted profiles are in close agreement with experimental values, with an error coefficient exceeding R = 0.91. When subjecting the system to a 25% variation in flue gas inflow, the carbon capture rate exhibits a significant fluctuation (7–10%) for both increasing and decreasing cases. In addition, the validated model is scaled-up to simulate the industrial-scale ammonia-based absorption process of carbon dioxide. The simulation incorporates a column with intercooling after each layer of packing. The results indicate that by minimizing the temperature within the column, the concentration of ammonia in the clean gases obtained at the top remains below 10 ppm, while the capture rate increases up to 94%. Furthermore, the analysis of a predetermined scenario reveals that the model can effectively replicate the behavior of the system under various conditions. This finding highlights its potential utility for future applications, including process optimization and the implementation of control techniques aimed at mitigating the above-mentioned drawbacks, such as solvent loss due to vaporization.

Mass transfer mechanism and model of CO2 absorption into a promising DEEA-HMDA solvent in a packed column

Mass transfer performance plays an important role in solvent evaluation as well as design and scale-up of CO2 absorption process. The mass transfer process of CO2 absorption into blended DEEA -HMDA solution was studied over different operating conditions in a lab-scale absorption column packed with Sulzer DX structured packing. The effect of those operating parameters on KGav was fully investigated and discussed in this work. Meanwhile, mass transfer mechanism of CO2 absorption into blended DEEA-HMDA solution was comprehensively presented by identifying the rate-controlling step of mass transfer and the reaction zone of CO2 with amines, which could provide the operation guideline for running plans. In addition, a new KGav model was proposed and developed on basis of the observed experimental value of KGav, which gave a much better predication performance in comparison with empirical Kohl-Risenfield-Astarita model and Sheng model with respect to AAD.

The effect of pressure on the concentration of methane and carbon dioxide absorption in biogas

Biogas is playing a vital role in the emerging market for renewable energy. Biogas is an alternative energy that can be used as a substitute for fossil energy. The main composition of biogas is methane gas (CH4) and carbon dioxide gas (CO2) with a small amount of hydrogen sulfide (H2S). Therefore, it is necessary to do treatment to enrich gas methane and reduce CO2 and H2S content in optimizing the use of biogas. Absorption is a CO2 capture technology often used in the chemical industry. A chemical absorption technique using a solvent solution is one of the most widely used techniques to capture CO2. This research uses MDEA (Nmethyldiethanolamine) solvent as an alkanolamine solution dissolved in water. The unit operation usually used to carry out the absorption process is an absorber, and the type of absorber used is a spray column absorber. Simulating variations in pressure on the absorber was conducted in this research. The result of this research is that the increase in pressure will increase the composition percent of CH4 in sweet gas and increase the amount of CO2 absorption in biogas. The best result of absorber pressure is obtained at a pressure of 48 bar. The purity of CH4 and %removal of CO2 in biogas can be solved simply by using the evaluation parameters of the various absorber pressures presented, which we expect to contribute to the biogas industry in the future.

Machine Learning Applied to X-Ray Spectra: Separating Stars in Orion Nebula Cluster from Active Galactic Nuclei in CDFS

Modern X-ray telescopes have detected hundreds of thousands of X-ray sources in the universe. However, current methods to classify these sources using the X-ray data themselves suffer problems—detailed X-ray spectroscopy of individual sources is too time consuming, while hardness ratios often lack accuracy, and can be difficult to use effectively. These methods fail to use the power of X-ray CCD detectors to identify X-ray emission lines and distinguish line-dominated spectra (from chromospherically active stars, supernova remnants, etc.) from continuum-dominated ones (e.g., compact objects or active galactic nuclei, AGN). In this paper, we probe the use of artificial neural networks (ANN) in differentiating Chandra spectra of young stars in the Chandra Orion Ultradeep Project (COUP) survey from AGN in the Chandra Deep Field South (CDFS) survey. We use these surveys to generate 100,000 artificial spectra of stars and AGN, and train our ANN models to separate the two kinds of spectra. We find that our methods reach an accuracy of ∼92% in classifying simulated spectra of moderate-brightness objects in typical exposures, but their performance decreases on the observed COUP and CDFS spectra (∼91%), due in large part to the relatively high background of these long-exposure data sets. We also investigate the performance of our methods with changing properties of the spectra such as the net source counts, the relative contribution of background, the absorption column of the sources, etc. We conclude that these methods have substantial promise for application to large X-ray surveys.

Investigation of Applying Technical Measures for Improving Energy Efficiency Design Index (EEDI) for KCS and KVLCC2

While extensive research is being conducted to reduce greenhouse gases in industrial fields, the International Maritime Organization (IMO) has implemented regulations to actively reduce CO2 emissions from ships, such as energy efficiency design index (EEDI), energy efficiency existing ship index (EEXI), energy efficiency operational indicator (EEOI), and carbon intensity indicator (CII). These regulations play an important role for the design and operation of ships. However, the calculation of the index and indicator might be complex depending on the types and size of the ship. Here, to calculate the EEDI of two target vessels, first, the ships were set as Deadweight (DWT) 50K container and 300K very large crude-oil carrier (VLCC) considering the type and size of those ships along with the engine types and power. Equations and parameters from the marine pollution treaty (MARPOL) Annex VI, IMO marine environment protection committee (MEPC) resolution were used to estimate the EEDI and their changes. Technical measures were subsequently applied to satisfy the IMO regulations, such as reducing speed, energy saving devices (ESD), and onboard CO2 capture system. Process simulation model using Aspen Plus v10 was developed for the onboard CO2 capture system. The obtained results suggested that the fuel change from Marine diesel oil (MDO) to liquefied natural gas (LNG) was the most effective way to reduce EEDI, considering the limited supply of the alternative clean fuels. Decreasing ship speed was the next effective option to meet the regulation until Phase 4. In case of container, the attained EEDI while converting fuel from Diesel oil (DO) to LNG was reduced by 27.35%. With speed reduction, the EEDI was improved by 21.76% of the EEDI based on DO. Pertaining to VLCC, 27.31% and 22.10% improvements were observed, which were comparable to those for the container. However, for both vessels, additional measure is required to meet Phase 5, demanding the reduction of 70%. Therefore, onboard CO2 capture system was designed for both KCS (Korea Research Institute of Ships & Ocean Engineering (KRISO) container ship) and KVLCC2 (KRISO VLCC) to meet the Phase 5 standard in the process simulation. The absorber column was designed with a diameter of 1.2–3.5 m and height of 11.3 m. The stripper column was 0.6–1.5 m in diameter and 8.8–9.6 m in height. The obtained results suggested that a combination of ESD, speed reduction, and fuel change was effective for reducing the EEDI; and onboard CO2 capture system may be required for Phase 5.

A pilot study comparing MEA and AEEA solvents in carbon capture

The goal of reducing the energy consumption of the CO2 removal process from flue gas may be pursued by modifying the process flow system, insertion of new technical solutions or developing new solvents. This paper provides data and discussion of the pilot plant experimental results using an aqueous 2-(2-aminoethylamino)ethanol (AEEA) compared to ethanolamine (MEA) solution. The post-combustion carbon capture pilot plant study was conducted with stripper inter-heating for advanced various flow systems, mainly for multi absorber feed (MAF) process setups, namely one with the lean amine stream being split 50/50 and served at different heights of the absorption column. A comparison with the standard (S) and split flow (SF) process flow modification has been also performed. The test showed that unskillful running of the process with AEEA solution can lead to excessive heat consumption, higher than for MEA.

Experimental and modelling approach to the design of chemical absorption columns with fast gas-liquid reaction: A case-study on flue-gas desulfurization with H2O2 oxidative solutions

In this work, we propose a methodology to approach the design of chemical absorption columns with fast gas-liquid reactions by an experimental and modelling study, which accounts for thermodynamic (solubility) data, mass-transfer phenomena, and the reaction kinetics contribution. As a reference case, the SO2 absorption in aqueous solution of H2O2 at different concentrations, which oxidizes SO2 to sulfuric acid, is considered. A lab-scale fed-batch bubble column is used to evaluate SO2 solubility dataset in absorbing solutions of distilled water containing different dosages of H2O2. A thermodynamic model is developed and validated in a Thermodynamic Flash block of ASPEN PLUS®, allowing to describe the experimental results with optimum agreement. For kinetic experiments, a lab-scale falling-film absorber is used to investigate both SO2 mass-transfer rates and the fundamental kinetic aspects of an absorption process with chemical reaction. The physical contribution to the mass-transfer rate is evaluated through a set of dedicated experiments, which allowed determining gas-side (kGa) and liquid-side (kLa) coefficients in the falling-film absorber. Subsequently, the Enhancement factor (EL) of the SO2 oxidative absorption is evaluated for the oxidizing reaction (SO2 + H2O2 → H2SO4) under the explored experimental conditions, using the equilibrium dataset and the mass transfer coefficients previously obtained. Finally, EL is correlated to the Hatta number (Ha) with the Danckwerts kinetic model as a pseudo-mth-nth-order non-reversible reaction type and the model kinetic parameters are calculated.

A review of process intensified CO2 capture in RPB for sustainability and contribution to industrial net zero

Carbon dioxide (CO2), a significant greenhouse gas released from power plants and industries, substantially impacts climate change; minimizing it and achieving carbon net zero is essential globally. In the direction of reducing CO2 emissions into the atmosphere, post-combustion carbon capture from large point CO2 emitters by chemical absorption involving the absorption of this gas in a capturing fluid is a commonly used and efficacious mechanism. Researchers have worked on the process using conventional columns. However, process intensification technology is required because of the high capital cost, the absorption column height, and the traditional columns’ low energy efficiency. Rotating packed bed (RPB) process intensification equipment has been identified as a suitable technology for enhanced carbon capture using an absorbing fluid. This article reviews and discusses recent model developments in the post-combustion CO2 capture process intensification using rotating packed beds. In the literature, various researchers have developed steady-state mathematical models regarding mass balance and energy balance equations in gas and liquid phases using ordinary or partial differential equations. Due to the circular shape, the equations are considered in a radial direction and have been solved using a numerical approach and simulated using different software platforms, viz. MATLAB, FORTRAN, and gPROMS. A comparison of various correlations has been presented. The models predict the mole fraction of absorbed CO2 and correspond well with the experimental results. Along with these models, an experimental data review on rotating packed bed is also included in this work.

Robust synthesis of amine-based natural gas sweetening plants

The natural gas processing and refining industry uses acid gas removal units to improve the quality of their sour gas feed to a certain level. Various disturbances such as sour gas feed conditions or solvent quality can influence the operation of such plants. A framework is developed using linear control tools which can be used to assess the flexibility of the operating condition of a sweetening plant against such disturbances. A quantitative measure of the flexibility and controllability of a design is provided as a systematic tool for the designer to evaluate different process structures or conditions. The framework can also be used to calculate the maximum tolerable disturbances by the process. The framework is illustrated in a plant that removes acid gas from a raw gas stream using MDEA as the solvent. The parameter σ1 as the maximum singular value of the steady state transfer matrix of the plant is considered as the sensitivity of the outlet H2S and CO2 purities against external disturbances where a higher value means more sensitivity. The results show that higher solvent concentrations are preferred considering the robustness of the absorption column against the sour gas feed disturbances and the uncertainties of the solvent properties. For example, at the solvent flow rate of 40,000 kg/h, the value of σ1 is 2.817, 0.736 and 0.148 at the wt% of 20%, 30% and 40%, respectively. Also, it is shown that for a plant designed with the sweet gas H2S purity of 2 ppm, when a solvent with 20 wt% and flow of 88897.3 kg/h is used, the feed quality disturbance of 0.59 kg/h and 505.19 kg/h in the H2S and CO2 mass flows relative to their nominal can be tolerated before reaching the maximum allowable value of 3 ppm. Such calculations at the 45% point with solvent flow of 44015.8 kg/h lead to the maximum tolerable disturbance of 1.79 kg/h and 967.36 kg/h in the H2S and CO2 flows. The rationale behind this behavior can be well understood if the plot of acid gas loading of rich amine is considered. A lower acid gas loading is observed at higher solvent wt% which means that more free solvent molecules are available in the solvent stream to absorb new acid gases. Accordingly, it has a better capability of confronting external disturbances. Also, the effect of the number of stages of the absorption column on the maximum tolerable disturbance is studied. It is concluded that the robustness of the process will decrease against both types of disturbances as the number of stages increases and lower disturbances can be handled without H2S outlet constraint violation.