Packed Absorption Column Research Articles

Effect of Liquid Flow Rate on Carbon Dioxide Absorption Performance Using Aqueous Potassium Carbonate Promoted with Glycine at Elevated Pressure Condition of Packed Absorption Column

This paper presented the absorption removal efficiency for carbon dioxide (CO2) removal from natural gas using an environmental friendly solvent, potassium carbonate promoted with glycine. Recently, CO2 capture using this solvent (with precipitating) was studied by previous researchers. However, the precipitates of the solvent increase the potential of blockage in the packing and piping thus result failure in absorption processes. Therefore, this study focused to assess the CO2 removal efficiency of non-precipitating potassium carbonate promoted with glycine. This green solvent contains aqueous blend of 20 wt% potassium carbonate and 8 wt% glycine. The absorption performance of the solvent was obtained by demonstrated a few experimental works using a bench scale packed absorption column. The packing type was Sulzer metal gauze and the column consisted of six sampling point which located equidistance along the packing. The effect of liquid flow rate was assessed in term of its CO2 removal efficiency and concentration profile along the packing. The study shows the increasing trend of CO2 removal as liquid flow rate increases. Higher liquid/molar flow rate gas (L/G) offers a better absorption performance compared to lower L/G ratio. The results demonstrated the efficient absorption up to 77% using non-precipitating potassium carbonate promoted with glycine.

Modeling of CO2-MEA absorption system in the packed column using Sulzer DX structured packing

The accurate design of a packed column is largely dependent upon the accurate calculation of the effective mass transfer area (ae ) of a packing. The experimental and the modelling study for the packed column with CO2-Monoethanolamine (MEA) system has been reported by employing Sulzer DX packing. The model validation results revealed that the modification in the available simple ae correlations is necessary to attain the reliable results using Sulzer DX packing. Recently, a new simple ae correlation suitable for Sulzer DX packing with MEA-CO2 system has been reported. Therefore, in the present study, the rate-based model is developed using the newly developed ae correlation for the packed absorption column with Sulzer DX structured packing for CO2-MEA system. The model has been successfully validated with the experimental data. Overall results depict good accuracy (AAD < 15%) of predicted CO2 concentration profiles due to the reliable ae calculations. However, the relative accuracy is low at high liquid flowrates (> 8 m3/m2h) due to the design limitations of the ae correlation. Therefore, in this study, the adopted ae mass transfer correlation is found suitable for the reliable modelling of the packed absorption column with Sulzer DX packing.

Comparison of sulfin hydrogen cleaning processes in a gas mixture in a packed adsorporal and electrochemical reactors

In this article given a comparative economic and environmental calculation of the use of a packed absorption column and an electrochemical reactor designed to purify air of hydrogen sulfide in the processes of ensuring environmental safety from potentially negative impacts of the surrounding technical facilities of the city, accompanied by emissions of hydrogen sulfide generated in sewers and emitted into the air of settlements. A significant advantage of the electrochemical air purification from hydrogen sulfide is shown compared with the absorption method of cleaning in packed columns using an aqueous solution of monoethanolamine as an absorbent. On the basis of practical experimental data, the optimal technological parameters of the process of electrochemical oxidation of hydrogen sulfide (current and voltage values) and the circuit diagram of a flow-through electrochemical reactor are determined.

Assessment of ionic liquids as H2S physical absorbents by thermodynamic and kinetic analysis based on process simulation

A comprehensive evaluation of ionic liquids (ILs) as potential H2S absorbents was performed using both molecular and process simulation. First, the Conductor-like-Screening MOdel for Real Solvents (COSMO-RS method) was applied to select promising ILs absorbents and to understand the H2S gas solubility from a molecular point of view. The ILs screening more than 700 ionic combinations determines that H2S physical absorption is mainly controlled by the hydrogen-bond acceptor capacity of the anion, due to the easily hydrogen bond formation when mixed with the acidic solute. Based on molecular simulation analysis, 6 ILs of different nature were evaluated in a typical industrial packed absorption column using COSMO-based/Aspen Plus methodology. Equilibrium based simulations demonstrated higher H2S separation efficiency (i.e. lower solvent expenses and smaller equipment sizes) when increasing H2S absorption capacity of the IL solvent. In contrast, rigorous process simulation analysis (including kinetic equations) reveals a strong mass transfer kinetic control in the H2S absorption in commercial packed column, which severely limits the maximum H2S absorption given by thermodynamics. As a result, ILs that present the best performance in the thermodynamic aspect, become worse for the operation. In fact, it was found that H2S recovery at given operating conditions increases when decreasing the viscosity of IL, being 1-ethyl-3-methylimidazolium dicyanamide, the one that presents the best absorbent performance, requiring the lowest operating temperatures and liquid volume flows. Lastly, the absorption operation was designed to achieve fixed H2S recovery using different liquid/gas feed ratios, resulting in column heights and diameters inside the typical range marked by heuristic rules for usual industrial packed columns. In sum, current prospective study based on COSMO-RS and Aspen Plus have been proved as a useful tool to analyze the potential industrial application of ILs in the H2S capture and to select the most adequate ILs, before starting with experimental tests, highly demanding in cost and time.

Rate-Based Modeling for Packed Absorption Column of the MEA–CO2–Water System at High-Pressure and High-CO2 Loading Conditions

Pandya proposed the first steady-state rate-based model for the chemical absorption process in a packed column using the aqueous CO2–MEA system. Later several modeling studies are also reported bas...

3D printed structures for optimized carbon capture technology in packed bed columns

ABSTRACTThe use of 3D printed structured packing for the optimization of aqueous-amine based carbon capture in packed absorption columns is examined in this paper. An experimental testing system has been set up, and initial comparisons were made between metal, plastic, and 3D printed 16-inch packing elements and between three 8-inch 3D printed elements of different densities. Pressure drop measurements were obtained at various air flowrates under dry conditions. Measurements were also taken for a wet system by adding water at six different liquid flowrates. In each case, theoretical calculations for pressure drop were performed based on a model presented in the literature. It was found that, for the 16-inch dry column, the model slightly overpredicts the pressure drop. The model provides an accurate prediction for the dry 8-inch experimental data, especially for the two least dense packing elements. For the wet system, the model overpredicts the pressure drop, likely due to modeling deficiencies when the column reaches its loading limit. These results provide sufficient confidence to move forward with testing and process intensification of the CO2 capture process.

CO2 REMOVAL EFFICIENCY FROM NATURAL GAS AT ELEVATED PRESSURE OF PACKED ABSORPTION COLUMN USING POTASSIUM CARBONATE PROMOTED WITH GLYCINE

This article reports the absorption removal efficiency for carbon dioxide (CO2) capture from natural gas using an environmental friendly solvent, potassium carbonate promoted with glycine. Recently, CO2 capture using this solvent (with precipitating) was studied by previous researchers. However, the precipitates of the solvent increase the potential of blockage in the packing and piping thus result failure in absorption processes. Therefore, this study focused to assess the CO2 removal efficiency of non-precipitating potassium carbonate promoted with glycine. This green solvent contains aqueous blend of 20 wt% potassium carbonate and 8 wt% glycine. The absorption performance of the solvent was obtained by demonstrated a few experimental works using a bench scale packed absorption column. The packing type was Sulzer metal gauze and the column consisted of six sampling point which located equidistance along the packing The system was running over a range of liquid flow rate 1.81-7.22 m3/m2.h at fixed operating pressure (4 Mpa), CO2 inlet concentration (20%), gas flow rate (33 kmol/m2.h) and solvent temperature (60 . The effect of liquid flow rate was assessed in term of its CO2 removal efficiency and concentration profile along the packing. The study shows the increasing trend of CO2 removal as liquid flow rate increases. Higher liquid/molar flow rate gas (L/G) offers a better absorption performance compared to lower L/G ratio. This study demonstrated the efficient absorption up to 77 % using non-precipitating potassium carbonate promoted with glycine.

Calculation of a packed column for absorption of hydrogen sulfur from gases formed by separation of crude oil

According to the well-known calculating algorithm for the packed absorption column, the main technological parameters and geometric dimensions of the apparatus for hydrogen sulfide containing gases, formed during the separation of crude oil, are determined. A 2,5-n solution of monoethanolamine is selected as the absorbent. Comparative results of the calculations are showing, that the working pressure in the column should be 4 atm, since with their lower values, the flow rate of the absorbent and the size of the column are increasing. The increase in working pressure is impractical, since it will require a transition from centrifugal and compresses pumps to piston pumps. ∏ The obtained parameters were compared for an absorption column in which the flow structure of the gas and liquid phases corresponds to ideal displacement, with the calculation results when the flow structure in the gas phase corresponds to the ideal displacement mode (as in the standard calculation algorithm) and in the liquid phase to ideal mixing. It is shown that, with the Peclet number of longitudinal diffusion pe&lt;40 the height and volume of the column increases by 10 and more percent and should be taken into account when packed columns, intended for absorption processes, are designed. At pe=30 the height and volume of the nozzle in the column increases by 27%. Another feature of the modelling and calculation of devices is a spike in concentration, meaning, that the lower part of the working line will cross the equilibrium. Calculations in thisparticular case show that at ≈ 11 the working line crosses the equilibrium and theoretically column height and volume →∞.

Mass Transfer Enhancement for CO2 Absorption in Structured Packed Absorption Column

The acidic gas, Carbon dioxide (CO2) absorption in aqueous ammonia solvent was carried as an example for industrial gaseous treatment. The packed column was provided with a novel structured BX-DX packing material. The overall mass transfer coefficient was calculated from the absorption efficiency of the various runs. Due to the high solubility of CO2, mass transfer was shown to be mainly controlled by gas side transfer rates. The effects of different operating parameters on KGav including CO2 partial pressure, total gas flow rates, volume flow rate of aqueous ammonia solution, aqueous ammonia concentration, and reaction temperature were investigated. For a particular system and operating conditions structured packing provides higher mass transfer coefficient than that of commercial random packing.

Geothermal power plant layouts with water absorption and reinjection of H2S and CO2 in fields with a high content of non-condensable gases

The reinjection of non-condensable gases (NCG) back to the geothermal reservoir has recently proved to be an effective emission abatement method in Iceland, yet it would raise new challenges when applied to geothermal fields with a much higher NCG content and different reservoir’s rock composition like the Italian fields. The features of the surface equipment to implement gas reinjection are rarely reported in the literature, being the attention mostly focused on the subsurface reservoir. To fill this gap, this study examines the integration of the water absorption and reinjection equipment in dry steam and flash steam geothermal power plants fed by steam with a high NCG content (8%). Three novel plant layouts are proposed, modelled and analysed which include a packed absorption column where H2S and CO2 are absorbed in water at high pressure. The study searches for those conditions ensuring an overall H2S abatement similar to that achieved by state-of-the-art emission abatement methods (e.g., AMIS) and, at the same time, enabling a significant capture of the CO2 contained in the geothermal steam, which is currently unabated. The results show that, with minimum modifications to the original plant layout, an overall H2S abatement of 86.5% and CO2 abatement of 47% are attainable. This is obtained using a column pressure of 36 bar, a water supply of 100 ton/hr, and coping with a net power output reduction of 6% and a moderate cost of the added equipment estimated equal to 1.0–2.2 M€.

Effects of operating parameters of packed columns on the K G a v for CO 2 absorption by amine solutions using optimization–simulation framework

Abstract The aim of this study is to investigate the effects of key operating parameters of packed absorption columns on the performance of mass transfer considering the volumetric overall mass transfer coefficient ( K G a V ). The effects were studied for CO2 absorption by using 4-diethylamino-2-butanol (DEAB) and N,N-Diethylethanolamine (DEEA) mixed with monoethanolamine (MEA) as novel amine solutions. In doing so, an optimization–simulation framework was developed based on the two-film theory model, thermodynamic model, multi-layer perceptron neural network (MLPNN), and statistical technique. To predict the CO2 loading as one of the parameters in input of MLPNN model, the Deshmukh–Mather model, as an electrolyte thermodynamic model, was developed for CO2 + DEAB + H2O and CO2 + DEEA + MEA + H2O systems. The effect of enhancement factor on the K G a V was considered based on the series resistances model including pseudo-first order enhancemnt factor and instantaneous enhancemnt factor. To optimize and rank the key operating factors that simultaneously affect the K G a V , the Taguchi method was used. Statistical indices showed that our model could efficiently predict the experimental data with AARDs of 5.6%, 0.43% and 4.96%, respectively, for K G a V data, CO2 loading data of DEAB and DEEA + MEA. A significant order of process variables affecting the K G a V values was as CO2 mole fraction > amine temperature > amine flow rate > gas temperature > packing type > CO2 loading > amine concentration. Moreover, the sensitivity analysis results showed that by increasing the CO2 mole fraction in gas feed, gas temperature, and CO2 loading, the K G a V values decreased, and by increasing the amine concentration, amine flow rate, and amine temperature, the K G a V values increased.

Modification of effective surface area correlation for structured packed absorption column at elevated pressures

Correlation for effective surface area is one of the important input for modeling of gas absorption in countercurrent packed column. Although the correlation previously developed by other researchers was able to provide quite decent prediction of carbon dioxide (CO2) absorption system, improvement still need to be done especially for high pressure condition whereby consideration for the decrease of effective surface area due to severe vapour backmixing situation needs to be taken into account. In this work, pressure dependent correction correlation was developed by incorporating the ratio of liquid to gas densities. The correlation developed in this study was found to successfully improve the prediction trend of the CO2 concentration profile along the column

Absorption methods for the determination of mass transfer parameters of packing internals: A literature review

Methods for the determination of mass‐transfer coefficients and effective interfacial areas in packed absorption columns are reviewed. For each parameter, the methods are grouped into categories on the basis of their physical principle; the chemical systems used, experimental protocol, and the advantages and inconveniences are discussed. The treatment of end effects, the influence of packed bed height, and the recent efforts in standardization of measurement methods are also treated. The aim of the review is to give a broad overview of the methods used in literature in the last eight decades, some of which might be reconsidered in the light of modern measurement techniques and to evaluate them in relation to precision, practicality and hazardousness thereby to facilitate the search for reliable, precise, and convenient experimental practices. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3246–3275, 2017

Process behaviour in a packed absorption column for high pressure CO2 absorption from natural gas using PZ + AMP blended solution

This paper reports the use of piperazine promoted 2-amino-2-methyl-1-propanol (PZ+AMP) blended solution for the removal of high concentration CO2 in natural gas (NG). The process behaviour was investigated by conducting the experiments in a bench-scale packed absorption column at high pressure conditions. The CO2 concentration and temperature profiles along the column were presented in order to study the process behaviour in the column at various operating pressures, CO2 concentration in NG, total gas flow rates, liquid flow rates, amine concentration and inlet liquid temperature. The temperature bulge was observed in the column and further discussed in this paper.

Continuous absorption of CO2 in packed column using MDEA solution for biomethane preparation

Nowadays, the energy consumption in Indonesia is increasing. Raising of energy consumption force Indonesia to find other energy resources. Biogas is one of the renewable energy, which was developed in anticipation to the fossil energy reduction. Reducing the content of impurities in biogas may reduce the corrosion impact and increase the combustion efficiency. The biomethane can be utilised as fuel for generator in small and medium scale industries (IKM). Continuous CO2 absorption in packed column using MDEA solution as absorbent is studied for biomethane preparation. CO2 absorption experiments was performed continuously in the packed absorption column with a diameter of 6 cm and 75 cm length. Gas is sparged from the bottom of the column while the liquid is pumped through the top of the column. The concentration of CO2 at exit gas is analysed by GC and recorded as a function of time. The flowrate of the inlet gas was varied at 1 LPM; 1.5 LPM; and 1.8 LPM. Variation of MDEA solution concentration used was 20% and 35.31%. Mathematical model for unsteady state CO2 absorption in packed column was developed. The reaction rate constant (k) and mass transfer coefficient KGa were determined by fitting the outlet CO2 concentration data as a function of time to the model solution with smallest Sum of Square of Errors (SSE). The experimental data shows that absorption of 1 LPM gas flow rate with 0,15 LPM MDEA solution flow rate may reduce 40 % CO2 to be 17 % CO2 in outlet gas. The steady state process reaches at 10 minutes. Increasing gas flow rates shows the higher overall mass transfer coefficient. The reaction rate constant is not affected by gas flow rate variation.

Modelling of high pressure CO2 absorption using PZ+AMP blended solution in a packed absorption column

Abstract A rate-based steady-state model for CO 2 absorption into a PZ+AMP blended solution is presented by taking into account the column hydraulics, mass transfer resistances and chemical reactions. The simulation results were compared with the experimental results of CO 2 absorption by a PZ+AMP blended solution in a packed absorption column at low and high CO 2 partial pressure conditions. The model predicts CO 2 concentration, amine concentration, the chemical enhancement factor, and liquid temperature profiles along the column. The model was in good agreement to predict the CO 2 concentration profiles along the column at low CO 2 partial pressure. However, it was found that the model needs to be corrected by introducing a correction factor for overall volumetric mass transfer coefficient ( K g a e ) for the simulation of CO 2 concentration profiles along the column at high CO 2 partial pressure conditions in the range of 404–1616 kPa.

Physical–chemical properties of gas–liquid contactors in packed absorption column

The burning of combustible material that produces emissions released to the atmosphere results in unfavorable climate change due to emissions of CO2, NOx, and acid rain by SOx, endangering the health of the population. The treatment of combustion gases by means of a packed absorption column with a high-efficiency liquid–gas contactor material reduces pollutant emissions to the atmosphere, where combustion gases make contact with aqueous amine solution of mono ethanol amine (MEA), using different structured packing materials which can be metallic, polymeric, or ceramic. The objective of this work is to study which one of these three types of materials of gas–liquid contactors presents the lowest deterioration in the presence of combustion gases flowing countercurrent to MEA. The materials were evaluated according to the Standard Test Methods ASTM G31-2004 for corrosion testing, ASTM E8-1998 for tension testing, ASTM E384-1990 for microhardness testing, ASTM G5-1999 for potentiodynamic and potentiostatic testing, and the procedure of NRF-194 PEMEX-2007. The properties studied were the tensile strengths, the hardness values, and the elastic moduli, before and after structured packing materials made contact with combustion gases in MEA aqueous solution. The results showed that in acidic and basic mediums, the metallic material was the most resistant to abrasion; it has the highest tensile strength, and presents more resistance during the stress test. The hardness results for the materials were metallic: 190 KH, polymeric: 20 KH, and ceramic: 700KH. The respective corrosion resistances in the presence of MEA were 1.63 × 10−3, 3.76 × 10−3, and 1.42 × 10−2 mm/year.

High pressure CO2 absorption from natural gas using piperazine promoted 2-amino-2-methyl-1-propanol in a packed absorption column

Monoethanolamine (MEA) is the most established solvent used in CO2 absorption studies at low-pressure conditions. However, it has several limitations, such as a low CO2 loading capacity, high degradation, and a tendency to corrode processing equipment. Therefore, this study reports the absorption performance of an alternative absorbent: the Piperazine (PZ) promoted 2-Amino-2-Methyl-1-Propanol (AMP) blended solvent for use in the removal of CO2 from natural gas (NG) in high pressure conditions. The performance of the PZ+AMP blended solvent was compared with the MEA solvent according to various operating pressures (0.1–4.0MPa), in percentage terms of CO2 removal efficiency, as well as the overall volumetric mass transfer coefficient for the gas phase based on unit mol fraction driving force (Kyav). The absorption experiments were conducted in an absorption column packed with Sulzer metal gauze packing for the effects of total gas flow rate (33–51kmol/m2h), liquid flow rate (2.89–3.97m3/m2h), MEA concentration (20–40wt%) and liquid temperature (30–45°C). From this study, the Kyav value of the 7wt% PZ+23wt% AMP blended solvent was higher than the value for 30wt% MEA solvent. Nonetheless, the Kyav values for both solvents increased from a rising operating pressure, most notably at operating pressures greater than 2.0MPa.

Effect of Liquid Flow Rate and Amine Concentration on CO&lt;sub&gt;2&lt;/sub&gt; Removal from Natural Gas at High Pressure Operation in Packed Absorption Column

Greenhouse gas (GHG) emissions such as carbon dioxide (CO2) and methane (CH4) from oil and natural gas operation at offshore platforms have significant contribution to global warming. The reduction of these GHG emissions is possible through CO2 capture technology. This study reports the absorption performance of monoethanolamine (MEA) for the removal of CO2 from natural gas (NG) at high pressure conditions. The absorption experiments were performed in an absorption column packed with Sulzer Metal Gauze Packing at 5.0 MPa operating pressure. The absorption performance was evaluated in terms of CO2 removal (%) with liquid flow rate ranging from 1.81 to 4.51 m3/m2.h and MEA concentration of 1.0 - 4.0 kmol/m3. It was found that CO2 removal (%) had increased with increasing liquid flow rate and MEA concentration.

Pilot plant results for a precipitating potassium carbonate solvent absorption process promoted with glycine for enhanced CO2 capture

The absorption performance of a glycine promoted precipitating potassium carbonate (K2CO3) solvent absorption process for carbon dioxide (CO2) capture has been presented using a laboratory scale pilot plant. Glycine has been added as a rate promoter to 40–45wt.% K2CO3 solutions to examine the enhancement of the CO2 absorption process. The laboratory scale pilot plant has been designed to capture 4–10kg/hr of CO2 from an air/CO2 mixture at a feed gas rate of 30–55kg/hr. Performance data of the absorber including pressure drop, holdup and CO2 removal efficiency has been collected from the pilot plant and presented for a range of operating conditions. The addition of glycine was found to improve the CO2 recovery rate by up to 6 times whilst also slightly increasing the pressure drop and holdup measured in the packed absorption column which is likely due to a reduction in the surface tension of the solvent. Additionally, increasing the K2CO3 solvent concentration and operating with a higher CO2 feed gas concentration were found to increase the CO2 recovery results. Finally performance data from the absorber has been used to validate an Aspen Plus simulation of the system.