Absorption Of Hydrogen Sulfide Research Articles

Double H-bonds multimer absorbent design for H2S absorption

A double H-bonds multimer absorbent for hydrogen sulfide (H2S) absorption was designed via intermolecular self-assembly using 1,8-Diazabicyclo-[5.4.0]-undec-7-ene (DBU) and ethylene glycol (EG) under the guidance of quantum chemical calculation (QCC). The formation mechanisms of multimer absorbents and the absorption mechanisms between those absorbents and H2S were explored by QCC and experiments. It was found that the formed multimer absorbent at the DBU/EG molar ratio of 1:2 has two intermolecular H-bonds with different strengths between DBU and EG, which can combine with H2S via strong intermolecular forces. Furthermore, the characteristics analysis of multimer absorbents and complexes confirmed the above mechanisms. Experimental results indicated that the DBU-2EG has a higher H2S solubility of 5.8 mol/kg multimer absorbent with a low viscosity value of 15.12 mPa·s at 25 °C and better regeneration performance. The multimer absorbent exhibits great potential in the H2S capture process.

Evaluation of amine-based ionic liquids as potential solvents for hydrogen sulfide absorption using COSMO-RS: Computational and experimental validation

Ionic liquids (ILs) is an effective way to convert and remove hydrogen sulfide, H2S from natural gas streams. Amine-based ILs have recently been discovered due to their efficiency of removing H2S due to their excellent characteristics. However, the selection of potential amine-based ILs from a wide range combination of cations and amine-based anions are rather challenging if performed experimentally. Conductor-like Screening Model for Real Solvents (COSMO-RS) was used for the prediction of liquids thermodynamics such as activity coefficient at infinite dilution, selectivity, capacity and performance index (PI) values to evaluate the performance of each amine-based ILs and determine the most efficient ILs for H2S absorption without requiring any experimental data. A total of 42 previously unexplored ionic liquids, amine-based ILs from a combination of 7 amine cations and 6 anions were screened by COSMO-RS model. The findings from COSMO-RS prediction results revealed that ILs without aromatic rings displayed higher efficiencies compared to ILs with aromatic rings. Moreover, N,N,N′,N′-tetramethyl-1,3-propanediamine chloride, [TMPDA][Cl] cation-anion combinations displayed the highest PI value of 52.55 among the screened ILs thus, predicted as the most efficient ILs for H2S absorption. The experimental results obtained validated the COSMO-RS predictions with an approximation of ± 4.51% discrepancies between predicted and experimental data. Hence, it is concluded that COSMO-RS can be used for a reliable pre-experimental prediction and amine-based ILs approach has a huge potential for effective H2S absorption in industrial applications.

CHEMISORPTION-CATALYTIC PROPERTIES OF ZINC OXIDE IN THE PROCESS OF REDUCTION OF PROPYL MERCAPTAN

In this work, the adsorption and catalytic properties of zinc oxide, which it exhibits in the process of desulfurization of propyl mercaptan, are studied. It is shown that zinc oxide obtained by ammonia-carbonate technology has a specific surface area of 40.34 m2/g. Nitrogen adsorption-desorption isotherms refer to type IV according to the IUPAC classification, which is typical for mesoporous materials. The calculation of the pore size distribution shows that ZnO contains pores with a diameter of 2 to 40 nm. The characteristics of the chemisorption-catalytic activity of zinc oxide are given. It has been established that during the catalytic reduction of C3H7SH with hydrogen, the formation and absorption of H2S with the formation of zinc sulfide occur. In this case, depending on the time of operation, there is a gradual decrease in the average size of crystallites of the ZnO phase and an increase in the size of crystallites of the zinc sulfide phase. The study of catalytic activity in the hydrogenation reaction of propyl mercaptan with hydrogen was studied during the full cycle of ZnO operation at temperatures of 350 and 400 °C in a flow-type installation. The stages of the process of interaction of the components of the gas mixture (propyl mercaptan and hydrogen sulfide) with zinc oxide are revealed. It is shown that in the initial period of ZnO operation, intense absorption of hydrogen sulfide occurs with the formation of a zinc sulfide phase. The appearance of hydrogen sulfide at the outlet of the catalytic reactor is fixed after 100-200 min of operation. The second stage is characterized by a rapid increase in the concentration of hydrogen sulfide at the outlet of the catalytic reactor with a simultaneous decrease in the concentration of propyl mercaptan. The third stage occurs after 450-550 min of operation and is characterized by the constancy of the composition of the gas mixture at the outlet of the reactor.

Application of TDLAS for measuring absorption coefficients of H2S rotational absorption lines near the wavelength of 2 µm

This paper presents the experimental measurement of hydrogen sulfide absorption coefficients in the pressure range of 75–460 mbar of two rotational absorption lines of the vibrational band of H2S molecule at 021-000 transition using the tunable diode laser absorption spectroscopy technique. The obtained results are compared with the data of the HITRAN spectroscopic database.

Study on the hydraulic condition of absorption tower of CGH unit for increasing the desulfurization capacity; simulation and execution results

Hydro-desulfurization processes are widely used in oil refineries to increase the quality of gasoline. The sulfur compounds react with hydrogen to produce hydrogen sulfide (H2S) gas. Hydrogen sulfide is absorbed on the absorption tower with an amine solution. In this study, the increase in desulfurization capacity was investigated by simulating the CGH unit of the IKORC (Imam Khomeini Oil Refinery Company). First, this unit was simulated with Aspen Hysys 11 software, which is accurate for refining processes. The simulation validity was obtained when the software output matched the vendor calculations and data. After ensuring the accuracy of the simulation, the maximum amount of amine flow has been obtained. This amount of amine has the maximum absorption of hydrogen sulfide. Any changes in temperature, pressure and the flow of gas and liquid streams can lead the absorption tower to destructive phenomena. The flooding in the absorption tower is the most significant effect of increasing the amine flow. This study purposed finding the maximum amine flow, away from flooding. For gasoline production with Euro 5 standard, maximum desulfurization is desirable, requiring the maximum amines flow in the adsorption tower. Finally, after presenting the results of this study, these changes in the process were implemented in the CGH unit. The execution of the obtained results strengthens the practical aspect of this study and confirms the simulation’s accuracy.

Intelligent modeling of the hydrogen sulfide removal by deep eutectic solvents for the environmental protection

Hydrogen sulfide (H2S) is an acidic gas which produces by both natural (hot spring, volcano, microorganism decomposition) and industrial (biogas production, natural gas, liquefied petroleum gas, and oil refineries) processes. Due to the highly toxic and corrosive nature of H2S, researchers continuously search to find a practical scenario for its elimination from gas and liquid mixtures. Hydrogen sulfide absorption by deep eutectic solvents (DES), has recently found considerable attention, mainly in laboratory-scale investigations. Despite a relatively comprehensive experimental analysis of H2S absorption by DESs, there is no reliable empirical or intelligent methodology to predict the amount of this removal. Thus, the current study utilizes three machine learning classes (i.e., artificial neural network, support vector regression, and hybrid neuro-fuzzy system) to estimate the amount of H2S removal by 18 different DESs. The DES composition and operating conditions are the independent variables of these intelligent tools. The relevancy analysis approves that the amount of absorbed H2S by DESs is mainly controlled by hydrogen bond acceptor type, pressure, and temperature. Statistical and graphical analyses approve that the hybrid neuro-fuzzy system (hybrid NFS) is the highest accurate model to estimate the DES-H2S phase equilibria. The hybrid NFS predicts 495 experimental samples of H2S removal by DESs with the AARD = 6.11 %, MAE = 0.064, RAE = 5.64 %, MSE = 0.0149, and R-value = 0.99709. The combination of [C1-TMHDA]Ac and acetamide (1:2) is the best DES to achieve the maximum level of H2S elimination.

Intensification of hydrogen sulfide absorption by diethanolamine in industrial scale via combined simulation and data-based optimization strategies

A novel combinatorial approach including computer-aided simulation and robust statistical data-based methods was introduced to intensify the chemical absorption process of H2S by diethanolamine (DEA) from sour industrial off-gas. Effects of three parameters (lean amine H2S impurity (LAHI), lean amine temperature (LAT) and column pressure (CP) on the alteration trends and sensitivity of H2S removal were studied using response surface methodology (RSM) and Sobol’s sensitivity analysis (SA). Then, the optimal conditions for maximizing the H2S removal were determined. Results depicted that H2S removal will be decreased at higher LAHI and LAT. SA showed that LAHI (83%) was the most impactful factor on H2S removal. LAT (15%) and CP (2%) showed a relatively-low and negligible effects on the removal efficiency, respectively. It was shown that low impact of LAT and CP on H2S removal arised from weak variations of thermodynamic parameters of H2S absorption (H2S solubility, equilibrium constant, and enthalpy of absorption) with those factors. Maximum H2S removal of 99.995% was resulted at the optimal values of LAHI = 0.01 molH2S/molDEA, LAT = 53.7 °C, and CP = 1500 kPa.

Effect of sodium dodecyl sulfate on CO2 and H2S absorption enhancement of functionalized multiwall carbon nanotubes in water: Experimental study and empirical model

A single bubble absorption column was used to examine the effect of hydrodynamic on carbon dioxide (CO2) and hydrogen sulfide (H2S) absorption in pure water and water-based nanofluids dispersed with neat, and OH and NH2 functionalized multiwall carbon nanotubes (MWCNTs). Sodium dodecyl sulfate (SDS) was used as a surfactant and stabilizer. The maximum absorption of CO2 and H2S were found to be 0.0038 mmol/m2·s and 0.056 mmol/m2·s using NH2-MWCNTs /nanofluid with 0.5 wt% content, respectively. The diffusion coefficients of gases into the nanofluids were computed by using an equation attained based on Dankwert’s theory. A last, an empirical correlation was proposed to determine the Sherwood number for the absorption of the aforementioned gases into the nanofluids.

Sb-Fe bimetallic non-aqueous phase desulfurizer for efficient absorption of hydrogen sulfide: A combined experimental and DFT study

Sb-Fe bimetallic non-aqueous phase desulfurizer for efficient absorption of hydrogen sulfide: A combined experimental and DFT study

Effect of nanoparticles on desulfurization/regeneration performance of deep eutectic solvent based nanofluid system

Using choline chloride as hydrogen bond acceptor and urea as hydrogen bond donor, the deep eutectic solvent (DES) was prepared, and different alkaline substances were added to obtain two alkaline DES systems with different viscosities. SiO2 nanoparticles were introduced into the above two systems to construct different DES-based nanofluid systems: ethanolamine-deep eutectic solvent (E-DES-NF) system and polyethyleneimine-deep eutectic solvent (P-DES-NF) system. The viscosity of the nanofluid system was measured, and it was found that with the increase of the proportion of nanoparticles, the viscosity of both nanofluids increased firstly and then decreased. The hydrogen sulfide absorption experiment was carried out to explore the effect of nanoparticles on the desulfurization and regeneration performance of different nanofluid systems. The experimental results showed that the DES system synthesized in this study can maintain 100% removal rate for at least 40 min. The desulfurization and regeneration performances were improved simultaneously after the addition of moderate nanoparticle. In the E-DES system, when the mass fraction of SiO2 nanoparticles was 0.1%, the highest desulfurization performance was conducted. Besides, the addition of an appropriate amount of water was found to be beneficial to the regeneration of exhausted desulfurizer of E-DES-NF system. In the P-DES-NF system, the optimal mass fraction of SiO2 nanoparticles was confirmed as 0.01%. Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction were used for the characterization of the nanofluid systems as well as SiO2 nanoparticles before and after absorption as well as after multiple absorption–regeneration cycles. The morphology of SiO2 nanoparticles itself had little changes. A large amount of liquid substances were found gather on the surface of nanoparticles, and with the increase of the number of absorption–regeneration cycles, the surface attachment gradually decreased.

Theoretical studies of H2S, SO2 and O2 absorption in mass exchanged apparatus with a continuous bubbling layer and mechanical dispersion of an absorbent

The paper reports the results of theoretical studies on kinetic and technological characteristics of oxygen, hydrogen sulfide and sulfur(IV) oxide absorption by water in mass-transfer apparatus of two various types: absorber with a continuous bubbling layer (AСBL) and horizontal absorber with bucket-shaped dispersers (HABD). The main purpose of these studies was the theoretical reasoning for the choice of mass-transfer equipment used in the purification of exhaust gases from sulfur compounds. It was shown that the resistance of the gas phase in ACBL is less than the resistance of the liquid phase by (2.75…3.78)106, (3.43…4.78)104, and (2.18…3.05)103 times for oxygen, hydrogen sulfide, and sulfur oxide, respectively; and it can be neglected when calculating the mass transfer coefficient. It was found that an increase in the diameter of the bubble from 1.510–3 m to 3.010–3 m leads to a decrease in the mass transfer coefficient by 1.63 times. It was calculated that the values of mass transfer coefficients in ACBL for H2S and SO2 are much higher than for O2, so the purification process will be controlled by the rate of oxygen absorption. It was found that the gas phase resistance during the absorption of oxygen and hydrogen sulfide for HABD has virtually no effect on the mass transfer coefficients and can be neglected. For the absorption of gases that are low-concentrated with respect to sulfur(IV) oxide, the mass transfer coefficient in HABD is determined by the resistance of the gas phase, and the optimal droplet diameter is within 2.00.5 mm. It was calculated that the technologically expedient initial speed of dispersed drops is 12 m/s, and their diameter is 1.5…3.0 mm for the industrial HABD. It was shown that the values of kinetic and technological indicators of mass transfer in HABD are several orders of magnitude higher than those in ACBL and have a significant potential for intensification.

Prediction of Ionic Liquids Performance for Hydrogen Sulfide Absorption from Natural Gas using COSMO-RS

The capability of ionic liquids (ILs) in various applications makes them attracted by many researchers. They have potential to be developed as “green” solvents for gas separation, especially hydrogen sulfide (H 2S) gas. In this work, it is attempted to predict the solubility of H 2S in ILs by COSMO-RS method. Since H 2S is a toxic pollutant, it is difficult to handle in the laboratory, therefore an appropriate model will be necessary in prior work. The COSMO-RS method is implemented to predict the Henry’s law constants and activity coefficient of H 2S in 140 ILs with various combinations of cations and anions. It is found by the screening that more H 2S can be absorbed in ILs with chloride ([Cl]-) and acetate ([Ac]-) anion. The solubility of H 2S in ILs with different alkyl chain at the cations not much affected and with different type of cations are slightly influence H 2S capture capacities. Even though the cations do not affect much in solubility of H 2S, the effectiveness of cation still need to be considered in different way. The prediction results only show their physical absorption ability, but the absorption of H 2S need to be consider chemically to get high capacity of absorption of H 2S.

Prevention and Control of Hydrogen Sulphide Accidents in Mining Extremely Thick Coal Seam: A Case Study in Wudong Coal Mine

Hydrogen sulphide is a toxic gas often present in coal seams and seriously threatens the lives and health of underground workers in coal mines. In this study, we theoretically modelled hydrogen sulphide generation in extremely thick underground coal mines with the +575 level #45 coal seam of Wudong Coal Mine as an example and obtained the on-site hydrogen sulphide emission pattern and spatial distribution features by combining field measurements and computational fluid dynamics simulation. The results showed that hydrogen sulphide mainly exists in the coal porous system in an adsorbed state. Because hydrogen sulphide has a molecular weight greater than the average molecular weight of air molecules, its concentration decreases with the increase of altitude to the bottom plate. When mining the upper stratified coal stratum, it diffuses widely in the working space; while when mining the lower coal stratum, it mainly concentrates at the bottom of the working face. Based on these analyses, on-site treatments were carried out using mixtures with different concentrations of sodium carbonate and sodium bicarbonate. In addition, different combinations of catalysts as well as type A and type B wetting agents were also tested. Eventually, a neutral KXL-I absorbent was developed, and the process of preinjecting absorbent and spraying absorbent was designed. The results showed that the newly developed KXL-I absorbent has high hydrogen sulphide absorption ability and is suitable for use as an absorbent in Wudong Coal Mine; preinjecting and spraying the absorbent can effectively prevent hydrogen sulphide disasters in the +575 level #45 coal seam in Wudong Coal Mine with the optimal final concentration of 0.9% and the absorption rate of 87% at the shearer of 66.6% at the support. Overall, our study provides valuable information for the prevention and control of hydrogen sulphide disasters in coal mines.

Подбор нейтрализаторов сероводорода для получения товарного мазута на Астраханском ГПЗ

The content of hydrogen sulfide in the gas condensate of the Astrakhan gas condensate field, which is the raw material of the Astrakhan gas processing plant (Astrakhan GPP), is about 26% by volume. The high content of sulfur compounds in the reservoir mixture leads to an increased content in the fraction of >350°C, which is obtained during the primary fractionation of stable condensate. The selection of an effective reagent for the absorption of hydrogen sulfide and mercaptans from fuel oil is a very urgent task that is important for the company’s economy. The results of laboratory tests of reagents-neutralizers are the first stage of admission to industrial use at the Astrakhan GPP. This article is devoted to the search for analogs of reagents-neutralizers for reducing hydrogen sulfide and mercaptans in the fuel oil of the Astrakhan GPP.

ИССЛЕДОВАНИЕ ПРОЦЕССА ОЧИСТКИ БИОГАЗА ОТ СЕРНИСТЫХ СОЕДИНЕНИЙ С ИСПОЛЬЗОВАНИЕМ АППАРАТА ВИХРЕВОГО СЛОЯ

The use of biogas for the operation of recycling equipment in its pure form is unacceptable due to the high content of sulfur compounds (hydrogen sulfide), which leads to corrosion of metal parts of the equipment contacting with biogas and reduces its service life. The article considers various ways of cleaning biogas from sulfur compounds. (Research purpose) The research purpose is in studying the process of biogas purification from sulfur compounds by sulfonating in the vortex layer apparatus. (Materials and methods) The laboratory of bioenergetic and supercritical technologies of VIM created an experimental device of a vortex magnetic layer. Authors used information research methods, including standard analytical methods of modern system approach, processing and analysis. (Results and discussion) The amount of hydrogen sulfide in the biogas was sharply reduced and when the gas stayed in the working chamber for 5 minutes, it did not exceed 20 parts per million. The concentration of carbon dioxide decreased slightly. The water in the working chamber of the installation serves as a solvent for incoming gases, and the ferromagnetic particles, when worn out, form a fine (20-50 micrometers) iron powder, which reacts chemically with dissolved hydrogen sulfide to form iron sulfide. Fast-rotating ferromagnetic particles create a large contact surface of liquid and gas, which improves the absorption of hydrogen sulfide and carbon dioxide. (Conclusions) It is possible to purify biogas from sulfur compounds by sulfonating in the vortex layer apparatus. The article proposes a method for improving the cleaning process by increasing the pressure and reducing the temperature of water in the working chamber of the vortex layer apparatus.

Comprehensive Computational Analysis Exploring the Formation of Caprolactam-Based Deep Eutectic Solvents and Their Applications in Natural Gas Desulfurization

Several deep eutectic solvents (DESs) have been recently developed for extraction of hydrogen sulfide from natural gas. Among these newly designed DESs, a combination of caprolactam and tetrabutylammonium halides at a molar ratio of 1:1, as the DESs, has the highest desulfurization efficiencies. In this work, we explored the formation of caprolactam-based DESs using molecular dynamics (MD) simulations and ab initio computations. The results, based on the time average of the equilibrated production run of MD simulations, revealed ∼15% decrease in the ionic interactions of tetrabutylammonium halides and, more interestingly, ∼92% decrease in the hydrogen bonds between caprolactam, thereby explaining the strong depression in the melting point observed in experiments during the formation of the DES. Next, simulations of the DES with mixtures of methane and hydrogen sulfide were performed to mimic the natural gas desulfurization process. Efficient absorption of hydrogen sulfide from natural gas under different operating conditions (5000 and 10,000 ppm H2S, at 25 and 60 °C, and at 1 and 10 bar) can be observed from the simulations. The results further unveiled strong interactions between the anions of the DESs and hydrogen sulfide, with interaction energies 10-fold higher than those of methane/hydrogen sulfide, explaining the mechanism of desulfurization by these DESs. Additionally, two different DESs composed of monoethanolamines/methyltriphenylphosphonium bromide and urea/choline chloride were used to evaluate and compare their capacity to absorb hydrogen sulfide; however, we observed that the caprolactam-based DESs are highly efficient, particularly at low temperatures, low pressures, and low fuel/DES mole ratios. As the existing literature covers only experiments on the removal of hydrogen sulfide via the DESs, the simulations presented herein provide insights into the mechanism of absorption, thereby paving a way forward for better design of the DESs.

Liquid-liquid phase-change absorption of hydrogen sulfide by superbase 1,8-diazabicyclo[5.4.0]undec-7-ene and its chemical regeneration

Here, we developed a novel absorbent for the sustainable capture of hydrogen sulfide (H2S), which is the blend of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-triethylene glycol dimethyl ether (TEGDME)-H2O. The results indicated that the gravimetric absorption capacity was 0.174 g H2S/g lower phase at 101.3 kPa and 15 °C, which was 1.3 times higher than that of widely used aqueous methyldiethanolamine (MDEA) solution under the similar condition. In addition, TEGDME was mainly remained in the upper phase, while H2S, H2O, and DBU were mainly concentrated in the lower phase. Moreover, only around 44 wt% of the total absorbent needed to be delivered to the stripper for desorption, and other portion of absorbent was directly sent to the absorption tower. Most importantly, this absorption system was demonstrated to be a benign medium for absorbent regeneration through the liquid-phase Claus process. Our results suggested that this DBU-TEGDME-H2O blend was promising for the sustainable H2S capture and conversion in industrial applications.

Oxidation absorption of hydrogen sulfide from gas stream using vacuum ultraviolet/H2O2/urea wet scrubbing system

Hydrogen sulfide has serious harm to human body and equipment. Advanced oxidation technology shows excellent development prospect for hydrogen sulfide (H2S) removal due to strong oxidation ability and green process. This article proposed a novel separation process for H2S from gas stream using vacuum ultraviolet (VUV)/H2O2/urea wet scrubbing system in a VUV-spraying scrubber, and studied the effectiveness of H2S removal and removal pathways using VUV/H2O2/urea wet scrubbing system. Results indicated that the highest H2S removal efficiency was up to 98.2 % under optimal experimental conditions. Increasing UV-light intensity and solution pH improved the H2S removal efficiency. Increasing flue gas flow rate and H2S concentration decreased the H2S removal efficiency. The increase of H2O2 concentration, reaction temperature, liquid-gas ratio or urea concentration first increased and then reduced the H2S removal efficiency. H2S was removed by five pathways such as ionization, urea absorption, H2O2 oxidation, photolysis and ·OH oxidation. Photolysis and ·OH oxidation were the two major pathways for the H2S removal.

Absorption removal of hydrogen sulfide from recirculated biogas

Abstract This study is focused on the effect of biogas recirculation with hydrogen sulfide removal on anaerobic treatment of sulfur-enriched synthetic wastewater in a UASB reactor. The presence of hydrogen sulfide in biogas causes problems in its further energy recovery while sulfides inhibit the anaerobic process. The reactor was gradually loaded with sulfates and their effect on the reactor operation was monitored. At the same time, external absorption of hydrogen sulfide from biogas with absorbent regeneration was operated. The results show that low concentrations of added sulfates support biogas production. At the sulfate concentration of 125 mg l−1, biogas production increased by approximately 2 l d−1. However, further increasing of the amount of sulfates in the substrate led to the opposite effect. At twice the amount of sulfates, the biogas production decrease by 1 l d−1 and its adverse effects on the removal of N-NH4, NC and P-PO4 were observed. Biogas recirculation through the absorption column ensured a decrease in the hydrogen sulfide concentration from 19 960 ppm to 4 030 ppm and an increase in the methane content from 59.2 % to 83 % and also a decrease in the sulfides concentration in the reactor. From the measured data it can be concluded that this method reduces sulfides inhibition.

Hydrogen sulfide solubility in 50 wt% and 70 wt% aqueous methyldiethanolamine at temperatures from 283 to 393 K and total pressures from 500 to 10000 kPa

The hydrogen sulfide (H2S) absorption capacity of a 70 wt% aqueous methyldiethanolamine (MDEA) solution was investigated in a static-analytic apparatus at temperatures of 283, 353 and 393 K and pressures of 2000, 6000 and 10000 kPa in the presence of methane. New experimental data were also produced for a 50.1 wt% aqueous MDEA at 323 K and pressures of 500 and 3000 kPa as part of the apparatus validation procedure. A model based on electrolyte non-random two-liquid (eNRTL) activity coefficient model to describe the liquid phase and Peng-Robinson Equation of State to describe the vapor phase non-idealities was developed for the system H2S-MDEA-H2O, which can potentially be used also for the system in the presence of methane at low pressures. Vapor pressure measurements of pure MDEA were also performed in the range of 405–435 K in an ebulliometer and parameters for the Antoine correlation were proposed.