- Email: [email protected]
Removal of MDEA foam creators using foam fractionation: Parametric study coupled with foam characterization
Accepted Manuscript Removal of MDEA Foam Creators Using Foam Fractionation: Parametric Study coupled with Foam Characterization Emad Alhseinat, Mahmoud Amr, Rami Jumah, Fawzi Banat PII:
S1875-5100(15)30018-4
DOI:
10.1016/j.jngse.2015.06.050
Reference:
JNGSE 850
To appear in:
Journal of Natural Gas Science and Engineering
Received Date: 8 March 2015 Revised Date:
3 June 2015
Accepted Date: 25 June 2015
Please cite this article as: Alhseinat, E., Amr, M., Jumah, R., Banat, F., Removal of MDEA Foam Creators Using Foam Fractionation: Parametric Study coupled with Foam Characterization, Journal of Natural Gas Science & Engineering (2015), doi: 10.1016/j.jngse.2015.06.050. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Removal of MDEA Foam Creators Using Foam Fractionation: Parametric Study coupled with Foam Characterization Emad Alhseinata*, Mahmoud Amrb , Rami Jumahb, Fawzi Banata of Chemical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi, United Arab Emirates b Department of Chemical Engineering, Jordan University of Science and Technology, Irbid, Jordan * Corresponding author: P.O Box 2533, Abu Dhabi, UAE E-mail address: [email protected]
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a Department
Abstract
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This work aimed at investigating the use of foam fractionation as a potential technique for contaminants removal from Methyldiethanolamine (MDEA) solutions. Industrial corrosion inhibitor was added as model contaminant and foam creator in gas sweetening units. The foaming tendency of aqueous MDEA solution was reported in terms of foam volume. Foam stability was reported on the basis of the time required for the last bubble to break. The effect of process parameters such as time of foamate collection, flowrate of dispersion gas, initial liquid
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volume, and corrosion inhibitor concentration on foam fractionation performance was investigated. Surface tension of collected samples from bulk liquid before and after foaming as well as from foamate was measured and correlated with the separation efficiency. Foaming was capable for separating and concentrating corrosion inhibitor into the foamate. The added
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corrosion inhibitor increased the foam breaking time and volume. Increasing amine volume at the same gas flowrate decreased the contaminants’ separation efficiency. The maximum
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separation was noticed at gas flowrate of 1.0 L/ min (0.009 m3/ m2.s). The observations of this study show that foam fractionation can be used effectively to remove surface active contaminates from MDEA amine solutions; however, operating conditions should be selected carefully.
1. Introduction
Amine foaming is a common problem in gas sweetening plants, which causes process upsets. The foam is caused by contaminants and degradation products present in the amine solvent. The current operating practices regarding foaming problems concern more in solving the incidents of foaming rather than develop a strategy to track the sources of foaming and alleviate them or
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reduce their impact. Where in fact, the focus should be on the separation of the sources of foam and eliminate them rather than trying to suppress the foam [1]. The separation of foaming creators is a very challenging and crucial step. Adsorptive bubble separation through foam fractionation is a very promising technique for the removal and separation of foaming creators.
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Foam fractionation is a technique for partially separating or concentrating dissolved material by adsorption at the surfaces of bubbles [2]. In view of the fact that the species responsible for foaming in gas sweetening units will tend to accumulate in the foam itself, it may be possible to concentrate them using foam fractionation in order to facilitate their removal.
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Foam fractionation has been used in applications involving separation and recovery of proteins, surfactants, and metals. Li et al [3] used foam fractionation to recover whey soy proteins from
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soy whey waste water. Several parameters like: sodium sulfite concentration, superficial gas velocity, and temperature were studied. Davis et al [4] used foam fractionation to recover fermentation products from culture broths. Another use of foam fractionation for surfactant recovery was reported by Rujirawanich et al [5]. They used multistage foam fractionator with bubble caps to remove cationic surfactants from water. They investigated the effects of design parameters and operating parameters on the overall multistage foam fractionator. The removal of
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metals (Calcium, Magnesium, and Iron) using foam fractionation was investigated by Rangarajan et al [6]. Foam fractionation column with reflux was designed, fabricated, and tested for the recovery of Cytel Pyridinium Chloride surfactant (CPC) by Wall [7]. The application of foam fractionation technology in the removal of amine contaminants was only reported by von
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Phul [8]. Unfortunately, there are no studies available in literature that can be considered as a systematic and quantitative investigation addressing the applicability of foam fractionation for
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amine solutions cleaning. The current knowledge is not adequate for the development of foam fractionation as cost-effective preventive and control technology for foaming in gas sweetening applications.
To the authors’ knowledge, there is no literature data about the effect of operating parameters on the separation performance of foam fractionation for the removal of foam creators from amine solutions. This work aimed at investigating the effect of some process parameters including foamate collecting time, dispersion gas flowrate, liquid height, and corrosion inhibitors
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concentration on the cleanup of foam creators from MDEA lean amine used in gas sweetening units.
2. Materials and methods
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The effect of the addition of industrial corrosion inhibitor on foaming behavior of 50 wt% MDEA was investigated initially. Then, parametric study on foam fractionation was carried out. The aim of this study as mentioned earlier is to investigate the effect of some process parameters i.e. foamate collecting time, dispersion gas flow rate, liquid height, and corrosion inhibitors
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concentration on removal of foam creators from the 50 wt% MDEA solution. 2.1 Materials
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Pure MDEA, lean MDEA, and industrial corrosion inhibitor were obtained from GASCO, Habshan, Abu Dhabi. 2.2 Experimental Setup
Foaming experiments were carried out using the pneumatic method modified from the standard ASTM D892 for foaming tests of lubricating oils [9]. As illustrated in Figure 1, the experimental
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setup was composed of a 500 ml graduated cylinder cell with cross sectional area of 0.0019 m2 and height of 0.34 m, a temperature bath, and a flow meter. Compressed and dry air was used as a dispersed gas bubbles to the tested amine solution. The same setup was used as a semi batch
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foam fractionation.
Fig. 1. Schematic diagram for semi batch foam fractionation experimental setup
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2.3 Experimental Procedures and conditions 2.3.1 Foaming Characterization Prior to each experiment, a 150 ml of the tested solution was placed into the test cell without
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mechanical shaking or stirring and then left in a water bath with fixed temperature (25oC) for approximately 20 minutes to reach thermal equilibrium. A gas diffuser was inserted into the test cell and left for approximately 5 minutes to be saturated with the test solution. Air was then introduced to the cell at a fixed volumetric flowrate of 1.0 L/min (0.009 m/s with respect to the
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cross section area of the graduated cylinder). A stopwatch was used to track duration of bubbling and breaking time. The test solution was vigorously bubbled by air through the gas diffuser with a blowing time of 20 min ±5 seconds. The blowing time was first counted when the first air
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bubble raised from the gas diffuser. The air was eventually released to the atmosphere from the outlet of the test cell.
During the blowing time, the foam volume above the gas dispersion layer was recorded during 20 minute. Prior to testing each specific contaminates, 50 weight% MDEA (without any additive) was run as a base line. The foaming tendency of MEDA was reported in terms of foam
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volume. Foam stability was reported on the basis of the time required for the last bubble to break after air flow was discontinued. 2.3.2 Foam Fractionation
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The same procedure was followed for the foam fractionation parametric study. However, the operating parameters, such as time, dispersion gas flow rate, feed flow rate, liquid height and initial feed contaminates concentration were varied one by one to examine their individual effect
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on separation performance. Three samples i.e. main solution sample (before foam separation), foamate sample and liquid sample (remaining MDEA solution in the foam fractionation column) were collected from each experiment and tested for surface tension. The Digital Tensiometer K9 (Kruss, Germany) was used to measure the surface tensions of the tested solutions as the main indicator of the separation performance. The resolution of the Digital Tensiometer K9 is 0.1 mN/m. Table 1 gives the experimental matrix that was followed in this study.
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Several samples were analyzed to evaluate the repeatability of the results. Selected experiments were repeated to test the reproducibility of the results. For surface tension measurements; at least five measurements were taken for each tested sample. Then, the stander deviation and stander error were calculated. All results were within the uncertainty of the used instrument. Selected
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foam and breaking time experiments have been repeated three times. The results in the repeated experiments indicate almost exact readings for foam volume with less than 1% deviation and 2% deviation in the breaking time readings.
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Table 1. Experimental Matrix Parameter Studied
Air Flowrate (L/min) 1 1 1 1 1 1 1 1 1 0.5 1.5 2 2.5 3 1 1 1 1
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Liquid Volume (mL) 150 150 150 150 150 150 100 200 250 150 150 150 150 150 150 150 150 150
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Corrosion Inhibitor Concentration (ppm) 25 50 100 250 500 1000 250 250 250 250 250 250 250 250 250 250 250 250
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Experiment #
Foam Collection Time (min) 5 5 5 5 5 5 5 5 5 5 5 5 5 5 0 10 15 20
3. Results and discussion 3.1 Corrosion inhibitor: Effect on foam behavior of 50 wt% MDEA solution Corrosion inhibitors are chemicals that are used in the industry to protect the metallic surfaces by forming a film on the surface to prevent it from corrosion, some corrosion inhibitors are surface active agents and thus it might have influence on the foam behavior of the amine solution.
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To investigate the effect of corrosion inhibitor on the foaming behavior of 50 wt % MDEA solution; a commercial corrosion inhibitor used in gas sweetening plant was added to 50 wt % MDEA solution. Foam volume, foam breaking time and solution surface tension were recorded. Figure 2 shows the effect of corrosion inhibitor concentrations on the surface tension of 50 wt%
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MDEA solution.
Fig. 2. Effect of commercial corrosion inhibitor on the surface tension of 50 wt% MDEA.
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As can be seen from Fig. 2, the addition of corrosion inhibitor decreased significantly the surface tension of the 50 wt% MDEA solution.
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Figure 2 illustrates the relation between concentration of corrosion inhibitor and surface tension. The data were fitted to Eq. 1 with R-squared value of 0.934 as follows: (1)
Where γ is the surface tension (mN/m), and CCI is the corrosion inhibitor concentration in ppm. To study the effect of corrosion inhibitor on foaming behavior of 50 wt% MDEA solution, different concentrations of corrosion inhibitor (25, 50, 100, 250, 500, and 1000 ppm) were added to 50 wt% MDEA solutions. Effect of the corrosion inhibitor on foam height and breaking time
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were recorded. For this experiment, the initial liquid height used was 150 mL, with an air flowrate of 1.0 L/min minute (0.009 m/s with respect to the cross section area of the graduated cylinder). Surface tension for the main solutions was measured and correlated to final foam volume. Figure 3 shows the relation between the final foam volume and the corrosion inhibitor
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concentration.
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Fig. 3. Effect of corrosion inhibitor concentration in 50 wt% MDEA foam volume. As shown in Fig. 3, increasing the concentration of the corrosion inhibitor increased the final
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foam volume. This can be related to the decrease of the surface tension of the MDEA solution as a result of the increase of corrosion inhibitor concentration. Figure 4 shows the effect of surface tension in foam volume. It can be seen that the foam volume increased as a result of surface tension decrease. This is maybe due to the increase of surface elasticity as a result of the decrease of surface tension.
Surface tension plays a major role in foam tendency through changing foam elasticity. Surface tension is force acting parallel to the surface which opposes any attempt to expand the surface area. Indeed, lower surface tension leads to more elastic surface; this will result in a greater foam
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volume. Thus surface tension can be considered as an indication of a solution’s tendency to foam [10-16]. The foam volume (Vfoam in mL) was correlated to the surface tension (γ in mN/m) by Eq. 2 with
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a value of 28, b value of 1581 and R-squared value of 0.996.
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(2)
Fig. 4. Effect of surface tension on foam volume of 50 wt% MDEA solution.
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Figure 5 shows increasing in foam breaking time as the corrosion inhibitor concentration increases. The increase in the corrosion inhibitor concentration decreases the surface tension of
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the solution which enhance the formation and stabilization of the foam.
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Fig. 5. Effect of corrosion inhibitor concentration on the foam breaking time of 50 wt% MDEA solution.
It can be concluded that increasing the concentration of the corrosion inhibitor will enhance the
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foam tendency and stability of 50 wt% MDEA. 3.2 Foam fractionation parametric study
A parametric study has been carried out to investigate the effect of initial feed contaminates concentration, foamate collecting time, dispersion gas flow rate and initial liquid height on the
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performance of foam fractionation for 50 wt% MDEA.
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3.2.1 Effect of Corrosion Inhibitor Concentration: The effect of corrosion inhibitor concentration was studied by adding different concentrations i.e. 25, 50, 100, 250, 500, and 1000 ppm, to 150 mL of 50 wt% MDEA solution with an air flowrate of 1 L/min (0.009 m/s). The surface tension of the foamate and the remaining liquid as a function of corrosion inhibitor concentration is shown in Table 2. The surface tension of the foamate is less than the remaining liquid and both are decreasing with increasing corrosion inhibitor concentration. This indicates that the corrosion inhibitor has been separated and concentrated in the foamate. Figure 6 shows the surface tension of the remaining liquid and foamate at different corrosion inhibitor concentration.
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Table 2. Effect of corrosion inhibitor concentration of foamate and liquid surface tension for 150 mL of 50 wt% MDEA solution with an air flowrate of 1 L/min. Liquid Surface Tension (mN/m) 54.04 ±0.12 52.48 ±0.05 52.52 ±0.06 48.32 ±0.12 43.30 ±0.06 42.18 ±0.11
Surface Tension Difference 0.44 0.20 2.26 8.24 2.72 4.44
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Foamate Surface Tension (mN/m) 53.60 ±0.13 52.28 ±0.10 50.26 ±0.04 40.08 ±0.07 40.58 ±0.08 37.74 ±0.06
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Corrosion Inhibitor Concentration (ppm) 25 50 100 250 500 1000
Fig. 6. Surface tension of liquid and foamate at different initial corrosion inhibitor concentration and 150 mL of 50 wt% MDEA solution with air flowrate of 1 L/min. The surface tension in the foamate is lower than the surface tension in the remaining liquid which indicts higher concentration of the corrosion inhibitor in the foamate and thus efficient separation of the corrosion inhibitor using the foam fractionation.
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3.2.2 Effect of solution Volume The effect of initial solution volume on the separation efficiency, in term of the difference between the surface tension in the remaining liquid and produced foamate, was studied by
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varying the solution volume of a 50 wt% MDEA with 250 ppm corrosion inhibitor and with an air flowrate of 1 L/min. The increase in liquid volume was inversely affected the extent of separation as shown in Fig. 7. As can be seen in Fig. 7 shows that the deference between the remaining liquid surface tension and the foamate surface tension decreased with increasing the initial liquid volume. Indeed, lower surface tension deference between the remaining liquid and
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the foamate indicates low separation efficiency and low corrosion inhibitor concentration in the foamate. This decrease in separation efficiency as a result of the increase in initial liquid volume
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can be due to the increase in foam wetness. This increase in foam wetness decreases the gravity drainage. Thus, more MDEA was carried over with the foam to the foamate solution which
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decreases the difference in the surface tension between the foamate and the remaining liquid.
Fig.7. Effect of initial solution volume on the separation efficiency, in terms of the difference between the surface tension in the remaining liquid and produced foamate for 50 wt% MDEA with 250 ppm corrosion inhibitor and air flowrate of 1 L/min.
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The above observation suggests that initial solution volume should not be chosen arbitrarily for foam fractionation application since the separation efficiency may deteriorate as a result of using un-optimized initial solution volume.
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3.2.3 Effect of Air Flowrate To investigate the effect of gas flowrate, the air flowrate was varied from 0.5 L/min (0.004 m/s) to 3.0 L/min (0.026 m/s) in 150 mL of 50 wt% MDEA solution with 250 ppm of corrosion inhibitor. Table 3 shows the surface tension of the remaining liquid and produced foamate. As
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can be seen in Fig. 8, the maximum separation was at gas flowrate of 1 L/min (0.009 m/s). It can be observed that at high gas flowrate, above 1.5 L/min, the separation efficiency was dramatically decreased. This is maybe because increasing gas flowrate increased the turbulence
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in the solution to the limit that disrupts the foam formation. Also this deteriorating of separation efficiency can be due to the decrease of the contact time between the bubbles and the corrosion inhibitor as a result of the increase in gas flowrate. The gas flowrate of 1 L/min (0.009 m/s) shows the biggest difference in surface tension between the remaining liquid and produced foamate and thus it was used as optimum air flowrate to investigate the effect of the other
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operating parameters.
Table 3. Effect of gas flowrate on the surface tension of the remaining liquid and produced foamate of 150 mL of 50 wt% MDEA solution with 250 ppm of corrosion inhibitor. Liquid Surface Tension (mN/m)
Difference in Surface Tension
0.004 0.009 0.013 0.018 0.022 0.026
44.98 46.54 43.36 48.38 47.86 48.74
47.6 49.82 46.34 48.04 47.48 48.74
2.62 3.28 2.98 -0.34 -0.38 0
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0.5 1 1.5 2 2.5 3
Foamate Surface Tension (mN/m)
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Air Flowrate (L/min)
Super facial velocity (m/s)
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Fig. 8. Effect of air flowrate on the separation efficiency, in term of the difference between the surface tension in the remaining liquid and produced foamate for 150 ml of 50 wt% MDEA with 250 ppm corrosion inhibitor. 3.2.4 Effect of foamate collecting time
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The effect of foamate collecting time was studied by varying the sampling time from 0.0 to 20 min for 150 mL of 50 wt% MDEA solution and 250 ppm of corrosion inhibitor using an air flowrate of 1 L/min. The surface tension of the remaining liquid and produced foamate is shown in Table 4. It was observed that the optimum foamate collection time is at 5 min from starting the
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experiment as shown in Fig. 9. This observation may be explained by the two following hypothesis: For very short time less than 5 min, the contact time between the gas bubbles and the
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corrosion inhibitor will not be enough to reach the maximum surface adsorption and thus the separation efficiency will not be the greatest. For longer time more than 5 min, the foam bubbles breaking will increase lead to loss of corrosion inhibitor from the foamate and higher mixing between the liquid and the foamate thus less difference in surface tension. Also long time will be sufficient to reach the critical micelles concentration (CMC) and thus the corrosion inhibitor will start to aggregate in micelles and back to the MDEA solution.
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Table 4. Effect of foamate collecting time on the surface tension of the remaining liquid and produced foamate for 150 mL of 50 wt% MDEA solution and 250 ppm of corrosion inhibitor using air flowrate of 1 L/min Liquid Surface Tension (mN/m) 52.3 51.74 52.14 50.54 49.48
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Foamate Surface Tension (mN/m) 47.74 43.24 48.08 46.64 44.86
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Foam collecting Time (mins) 0 5 10 15 20
Fig. 9. Effect of foamate collecting time on the separation efficiency, in term of the difference between the surface tension in the remaining liquid and produced foamate for 150 mL of 50 wt% MDEA solution and 250 ppm of corrosion inhibitor using air flowrate of 1 L/min
4. Conclusion The effect of the addition of industrial corrosion inhibitor on foaming behavior of 50 wt% MDEA was studied. Then, the effects of operating parameters i.e. foamate collecting time, dispersion gas flowrate, initial liquid volume, and initial corrosion inhibitor concentration on
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foam fractionation separation efficiency were investigated. It was found that increasing the concentration of the corrosion inhibitor increased the foam breaking time and volume. Increase initial liquid volume inversely affected the extent of separation due to the increase in foam wetness. The maximum separation was at gas flowrate of 1 L/min (0.007 m/s). It was observed
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that at high gas flowrates, above 1.5 L/min, the separation efficiency dramatically decreased. It was observed that the optimum foamate collection time is at 5 min from starting the experiment. These experimental observations can help to design more efficient foam fractionation unit for
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cleaning purposes of amine solution in industrial gas sweetening processes.
Acknowledgments funding the project (GRC006).
References
4.
5.
6.
7. 8. 9. 10.
11.
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3.
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2.
Pauley, C.R., Face the facts about amine foaming. Chemical Engineering Progress, 1991. 87(7): p. 33-38. Lemlich, R., CHAPTER 3 - PRINCIPLES OF FOAM FRACTIONATION AND DRAINAGE, in Adsorptive Bubble Separation Techniques, R. Lemlich, Editor 1972, Academic Press. p. 33-51. Li, R., et al., Pilot study of recovery of whey soy proteins from soy whey wastewater using batch foam fractionation. Journal of Food Engineering, 2014. 142(0): p. 201-209. Davis, D.A., H.C. Lynch, and J. Varley, The application of foaming for the recovery of Surfactin from B. subtilis ATCC 21332 cultures. Enzyme and Microbial Technology, 2001. 28(4–5): p. 346354. Rujirawanich, V., et al., Recovery of surfactant from an aqueous solution using continuous multistage foam fractionation: Influence of design parameters. Chemical Engineering and Processing: Process Intensification, 2012. 52(0): p. 41-46. Rangarajan, V. and R. Sen, An inexpensive strategy for facilitated recovery of metals and fermentation products by foam fractionation process. Colloids and Surfaces B: Biointerfaces, 2013. 104(0): p. 99-106. Wall, D., Advanced Chemical Separation Using Foam Fractionation, in Mansfield College2007, Oxford. Phul, S.A.V. Sweetening process foaming and abatement. in Laurance Reid Gas Conditioning Conference. 2001. (ASTM), A.S.f.T.a.M., ASTM D892- Standard Test Method for Foaming Characteristics of Lubricating Oil, 1999, ASTM: West Conshohocken, PA. Chen, X., S.A. Freeman, and G.T. Rochelle, Foaming of aqueous piperazine and monoethanolamine for CO2 capture. International Journal of Greenhouse Gas Control, 2011. 5(2): p. 381-386. Pauley, C.R., R. Hashemi, and S. Caothien, Analysis of Foaming Mechanisms in Amine Plants, P. Corporation, Editor 1988, American Institute of Chemical Engineer.
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The authors are grateful to the Gas Research Centre at The Petroleum Institute in Abu Dhabi for
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15.
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14.
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13.
Alhseinat, E., et al., Effect of MDEA degradation products on foaming behavior and physical properties of aqueous MDEA solutions. International Journal of Greenhouse Gas Control, 2015. 37(0): p. 280-286. Alhseinat, E., et al., Foaming study combined with physical characterization of aqueous MDEA gas sweetening solutions. Journal of Natural Gas Science and Engineering, 2014. 17(0): p. 49-57. Thitakamol, B. and A. Veawab, Foaming behavior in CO2 absorption process using aqueous solutions of single and blended alkanolamines. Industrial and Engineering Chemistry Research, 2008. 47(1): p. 216-225. Thitakamol, B. and A. Veawab, Foaming model for CO2 absorption process using aqueous monoethanolamine solutions. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2009. 349(1–3): p. 125-136. Wilson, A., Foams: Physics, Chemistry and Structure; Springer-Verlag1989, London, Great Britain: Springer-Verlag.
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Removal of MDEA Foam Creators Using Foam Fractionation: Parametric Study coupled with Foam Characterization Emad Alhseinata*, Mahmoud Amrb , Rami Jumahb, Fawzi Banata of Chemical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi, United Arab Emirates b Department of Chemical Engineering, Jordan University of Science and Technology, Irbid, Jordan * Corresponding author: P.O Box 2533, Abu Dhabi, UAE E-mail address: [email protected]
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• •
Foam fractionation as a potential technique for contaminants removal from Methyldiethanolamine (MDEA) solutions was investigated. The effect of process parameters on foam fractionation performance was studied. Industrial corrosion inhibitor was added as model contaminant and foam creator in gas sweetening units. Foam fractionation was capable for separating and concentrating surface active contaminates into the foamate.
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•
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a Department
1
S1875-5100(15)30018-4
DOI:
10.1016/j.jngse.2015.06.050
Reference:
JNGSE 850
To appear in:
Journal of Natural Gas Science and Engineering
Received Date: 8 March 2015 Revised Date:
3 June 2015
Accepted Date: 25 June 2015
Please cite this article as: Alhseinat, E., Amr, M., Jumah, R., Banat, F., Removal of MDEA Foam Creators Using Foam Fractionation: Parametric Study coupled with Foam Characterization, Journal of Natural Gas Science & Engineering (2015), doi: 10.1016/j.jngse.2015.06.050. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Removal of MDEA Foam Creators Using Foam Fractionation: Parametric Study coupled with Foam Characterization Emad Alhseinata*, Mahmoud Amrb , Rami Jumahb, Fawzi Banata of Chemical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi, United Arab Emirates b Department of Chemical Engineering, Jordan University of Science and Technology, Irbid, Jordan * Corresponding author: P.O Box 2533, Abu Dhabi, UAE E-mail address: [email protected]
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a Department
Abstract
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This work aimed at investigating the use of foam fractionation as a potential technique for contaminants removal from Methyldiethanolamine (MDEA) solutions. Industrial corrosion inhibitor was added as model contaminant and foam creator in gas sweetening units. The foaming tendency of aqueous MDEA solution was reported in terms of foam volume. Foam stability was reported on the basis of the time required for the last bubble to break. The effect of process parameters such as time of foamate collection, flowrate of dispersion gas, initial liquid
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volume, and corrosion inhibitor concentration on foam fractionation performance was investigated. Surface tension of collected samples from bulk liquid before and after foaming as well as from foamate was measured and correlated with the separation efficiency. Foaming was capable for separating and concentrating corrosion inhibitor into the foamate. The added
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corrosion inhibitor increased the foam breaking time and volume. Increasing amine volume at the same gas flowrate decreased the contaminants’ separation efficiency. The maximum
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separation was noticed at gas flowrate of 1.0 L/ min (0.009 m3/ m2.s). The observations of this study show that foam fractionation can be used effectively to remove surface active contaminates from MDEA amine solutions; however, operating conditions should be selected carefully.
1. Introduction
Amine foaming is a common problem in gas sweetening plants, which causes process upsets. The foam is caused by contaminants and degradation products present in the amine solvent. The current operating practices regarding foaming problems concern more in solving the incidents of foaming rather than develop a strategy to track the sources of foaming and alleviate them or
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reduce their impact. Where in fact, the focus should be on the separation of the sources of foam and eliminate them rather than trying to suppress the foam [1]. The separation of foaming creators is a very challenging and crucial step. Adsorptive bubble separation through foam fractionation is a very promising technique for the removal and separation of foaming creators.
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Foam fractionation is a technique for partially separating or concentrating dissolved material by adsorption at the surfaces of bubbles [2]. In view of the fact that the species responsible for foaming in gas sweetening units will tend to accumulate in the foam itself, it may be possible to concentrate them using foam fractionation in order to facilitate their removal.
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Foam fractionation has been used in applications involving separation and recovery of proteins, surfactants, and metals. Li et al [3] used foam fractionation to recover whey soy proteins from
M AN U
soy whey waste water. Several parameters like: sodium sulfite concentration, superficial gas velocity, and temperature were studied. Davis et al [4] used foam fractionation to recover fermentation products from culture broths. Another use of foam fractionation for surfactant recovery was reported by Rujirawanich et al [5]. They used multistage foam fractionator with bubble caps to remove cationic surfactants from water. They investigated the effects of design parameters and operating parameters on the overall multistage foam fractionator. The removal of
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metals (Calcium, Magnesium, and Iron) using foam fractionation was investigated by Rangarajan et al [6]. Foam fractionation column with reflux was designed, fabricated, and tested for the recovery of Cytel Pyridinium Chloride surfactant (CPC) by Wall [7]. The application of foam fractionation technology in the removal of amine contaminants was only reported by von
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Phul [8]. Unfortunately, there are no studies available in literature that can be considered as a systematic and quantitative investigation addressing the applicability of foam fractionation for
AC C
amine solutions cleaning. The current knowledge is not adequate for the development of foam fractionation as cost-effective preventive and control technology for foaming in gas sweetening applications.
To the authors’ knowledge, there is no literature data about the effect of operating parameters on the separation performance of foam fractionation for the removal of foam creators from amine solutions. This work aimed at investigating the effect of some process parameters including foamate collecting time, dispersion gas flowrate, liquid height, and corrosion inhibitors
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concentration on the cleanup of foam creators from MDEA lean amine used in gas sweetening units.
2. Materials and methods
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The effect of the addition of industrial corrosion inhibitor on foaming behavior of 50 wt% MDEA was investigated initially. Then, parametric study on foam fractionation was carried out. The aim of this study as mentioned earlier is to investigate the effect of some process parameters i.e. foamate collecting time, dispersion gas flow rate, liquid height, and corrosion inhibitors
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concentration on removal of foam creators from the 50 wt% MDEA solution. 2.1 Materials
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Pure MDEA, lean MDEA, and industrial corrosion inhibitor were obtained from GASCO, Habshan, Abu Dhabi. 2.2 Experimental Setup
Foaming experiments were carried out using the pneumatic method modified from the standard ASTM D892 for foaming tests of lubricating oils [9]. As illustrated in Figure 1, the experimental
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setup was composed of a 500 ml graduated cylinder cell with cross sectional area of 0.0019 m2 and height of 0.34 m, a temperature bath, and a flow meter. Compressed and dry air was used as a dispersed gas bubbles to the tested amine solution. The same setup was used as a semi batch
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foam fractionation.
Fig. 1. Schematic diagram for semi batch foam fractionation experimental setup
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2.3 Experimental Procedures and conditions 2.3.1 Foaming Characterization Prior to each experiment, a 150 ml of the tested solution was placed into the test cell without
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mechanical shaking or stirring and then left in a water bath with fixed temperature (25oC) for approximately 20 minutes to reach thermal equilibrium. A gas diffuser was inserted into the test cell and left for approximately 5 minutes to be saturated with the test solution. Air was then introduced to the cell at a fixed volumetric flowrate of 1.0 L/min (0.009 m/s with respect to the
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cross section area of the graduated cylinder). A stopwatch was used to track duration of bubbling and breaking time. The test solution was vigorously bubbled by air through the gas diffuser with a blowing time of 20 min ±5 seconds. The blowing time was first counted when the first air
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bubble raised from the gas diffuser. The air was eventually released to the atmosphere from the outlet of the test cell.
During the blowing time, the foam volume above the gas dispersion layer was recorded during 20 minute. Prior to testing each specific contaminates, 50 weight% MDEA (without any additive) was run as a base line. The foaming tendency of MEDA was reported in terms of foam
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volume. Foam stability was reported on the basis of the time required for the last bubble to break after air flow was discontinued. 2.3.2 Foam Fractionation
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The same procedure was followed for the foam fractionation parametric study. However, the operating parameters, such as time, dispersion gas flow rate, feed flow rate, liquid height and initial feed contaminates concentration were varied one by one to examine their individual effect
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on separation performance. Three samples i.e. main solution sample (before foam separation), foamate sample and liquid sample (remaining MDEA solution in the foam fractionation column) were collected from each experiment and tested for surface tension. The Digital Tensiometer K9 (Kruss, Germany) was used to measure the surface tensions of the tested solutions as the main indicator of the separation performance. The resolution of the Digital Tensiometer K9 is 0.1 mN/m. Table 1 gives the experimental matrix that was followed in this study.
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Several samples were analyzed to evaluate the repeatability of the results. Selected experiments were repeated to test the reproducibility of the results. For surface tension measurements; at least five measurements were taken for each tested sample. Then, the stander deviation and stander error were calculated. All results were within the uncertainty of the used instrument. Selected
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foam and breaking time experiments have been repeated three times. The results in the repeated experiments indicate almost exact readings for foam volume with less than 1% deviation and 2% deviation in the breaking time readings.
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Table 1. Experimental Matrix Parameter Studied
Air Flowrate (L/min) 1 1 1 1 1 1 1 1 1 0.5 1.5 2 2.5 3 1 1 1 1
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Liquid Volume (mL) 150 150 150 150 150 150 100 200 250 150 150 150 150 150 150 150 150 150
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Corrosion Inhibitor Concentration (ppm) 25 50 100 250 500 1000 250 250 250 250 250 250 250 250 250 250 250 250
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Foam Collection Time (min) 5 5 5 5 5 5 5 5 5 5 5 5 5 5 0 10 15 20
3. Results and discussion 3.1 Corrosion inhibitor: Effect on foam behavior of 50 wt% MDEA solution Corrosion inhibitors are chemicals that are used in the industry to protect the metallic surfaces by forming a film on the surface to prevent it from corrosion, some corrosion inhibitors are surface active agents and thus it might have influence on the foam behavior of the amine solution.
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To investigate the effect of corrosion inhibitor on the foaming behavior of 50 wt % MDEA solution; a commercial corrosion inhibitor used in gas sweetening plant was added to 50 wt % MDEA solution. Foam volume, foam breaking time and solution surface tension were recorded. Figure 2 shows the effect of corrosion inhibitor concentrations on the surface tension of 50 wt%
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MDEA solution.
Fig. 2. Effect of commercial corrosion inhibitor on the surface tension of 50 wt% MDEA.
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As can be seen from Fig. 2, the addition of corrosion inhibitor decreased significantly the surface tension of the 50 wt% MDEA solution.
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Figure 2 illustrates the relation between concentration of corrosion inhibitor and surface tension. The data were fitted to Eq. 1 with R-squared value of 0.934 as follows: (1)
Where γ is the surface tension (mN/m), and CCI is the corrosion inhibitor concentration in ppm. To study the effect of corrosion inhibitor on foaming behavior of 50 wt% MDEA solution, different concentrations of corrosion inhibitor (25, 50, 100, 250, 500, and 1000 ppm) were added to 50 wt% MDEA solutions. Effect of the corrosion inhibitor on foam height and breaking time
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were recorded. For this experiment, the initial liquid height used was 150 mL, with an air flowrate of 1.0 L/min minute (0.009 m/s with respect to the cross section area of the graduated cylinder). Surface tension for the main solutions was measured and correlated to final foam volume. Figure 3 shows the relation between the final foam volume and the corrosion inhibitor
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concentration.
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Fig. 3. Effect of corrosion inhibitor concentration in 50 wt% MDEA foam volume. As shown in Fig. 3, increasing the concentration of the corrosion inhibitor increased the final
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foam volume. This can be related to the decrease of the surface tension of the MDEA solution as a result of the increase of corrosion inhibitor concentration. Figure 4 shows the effect of surface tension in foam volume. It can be seen that the foam volume increased as a result of surface tension decrease. This is maybe due to the increase of surface elasticity as a result of the decrease of surface tension.
Surface tension plays a major role in foam tendency through changing foam elasticity. Surface tension is force acting parallel to the surface which opposes any attempt to expand the surface area. Indeed, lower surface tension leads to more elastic surface; this will result in a greater foam
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volume. Thus surface tension can be considered as an indication of a solution’s tendency to foam [10-16]. The foam volume (Vfoam in mL) was correlated to the surface tension (γ in mN/m) by Eq. 2 with
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a value of 28, b value of 1581 and R-squared value of 0.996.
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(2)
Fig. 4. Effect of surface tension on foam volume of 50 wt% MDEA solution.
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Figure 5 shows increasing in foam breaking time as the corrosion inhibitor concentration increases. The increase in the corrosion inhibitor concentration decreases the surface tension of
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the solution which enhance the formation and stabilization of the foam.
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Fig. 5. Effect of corrosion inhibitor concentration on the foam breaking time of 50 wt% MDEA solution.
It can be concluded that increasing the concentration of the corrosion inhibitor will enhance the
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foam tendency and stability of 50 wt% MDEA. 3.2 Foam fractionation parametric study
A parametric study has been carried out to investigate the effect of initial feed contaminates concentration, foamate collecting time, dispersion gas flow rate and initial liquid height on the
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performance of foam fractionation for 50 wt% MDEA.
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3.2.1 Effect of Corrosion Inhibitor Concentration: The effect of corrosion inhibitor concentration was studied by adding different concentrations i.e. 25, 50, 100, 250, 500, and 1000 ppm, to 150 mL of 50 wt% MDEA solution with an air flowrate of 1 L/min (0.009 m/s). The surface tension of the foamate and the remaining liquid as a function of corrosion inhibitor concentration is shown in Table 2. The surface tension of the foamate is less than the remaining liquid and both are decreasing with increasing corrosion inhibitor concentration. This indicates that the corrosion inhibitor has been separated and concentrated in the foamate. Figure 6 shows the surface tension of the remaining liquid and foamate at different corrosion inhibitor concentration.
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Table 2. Effect of corrosion inhibitor concentration of foamate and liquid surface tension for 150 mL of 50 wt% MDEA solution with an air flowrate of 1 L/min. Liquid Surface Tension (mN/m) 54.04 ±0.12 52.48 ±0.05 52.52 ±0.06 48.32 ±0.12 43.30 ±0.06 42.18 ±0.11
Surface Tension Difference 0.44 0.20 2.26 8.24 2.72 4.44
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Foamate Surface Tension (mN/m) 53.60 ±0.13 52.28 ±0.10 50.26 ±0.04 40.08 ±0.07 40.58 ±0.08 37.74 ±0.06
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Corrosion Inhibitor Concentration (ppm) 25 50 100 250 500 1000
Fig. 6. Surface tension of liquid and foamate at different initial corrosion inhibitor concentration and 150 mL of 50 wt% MDEA solution with air flowrate of 1 L/min. The surface tension in the foamate is lower than the surface tension in the remaining liquid which indicts higher concentration of the corrosion inhibitor in the foamate and thus efficient separation of the corrosion inhibitor using the foam fractionation.
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3.2.2 Effect of solution Volume The effect of initial solution volume on the separation efficiency, in term of the difference between the surface tension in the remaining liquid and produced foamate, was studied by
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varying the solution volume of a 50 wt% MDEA with 250 ppm corrosion inhibitor and with an air flowrate of 1 L/min. The increase in liquid volume was inversely affected the extent of separation as shown in Fig. 7. As can be seen in Fig. 7 shows that the deference between the remaining liquid surface tension and the foamate surface tension decreased with increasing the initial liquid volume. Indeed, lower surface tension deference between the remaining liquid and
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the foamate indicates low separation efficiency and low corrosion inhibitor concentration in the foamate. This decrease in separation efficiency as a result of the increase in initial liquid volume
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can be due to the increase in foam wetness. This increase in foam wetness decreases the gravity drainage. Thus, more MDEA was carried over with the foam to the foamate solution which
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decreases the difference in the surface tension between the foamate and the remaining liquid.
Fig.7. Effect of initial solution volume on the separation efficiency, in terms of the difference between the surface tension in the remaining liquid and produced foamate for 50 wt% MDEA with 250 ppm corrosion inhibitor and air flowrate of 1 L/min.
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The above observation suggests that initial solution volume should not be chosen arbitrarily for foam fractionation application since the separation efficiency may deteriorate as a result of using un-optimized initial solution volume.
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3.2.3 Effect of Air Flowrate To investigate the effect of gas flowrate, the air flowrate was varied from 0.5 L/min (0.004 m/s) to 3.0 L/min (0.026 m/s) in 150 mL of 50 wt% MDEA solution with 250 ppm of corrosion inhibitor. Table 3 shows the surface tension of the remaining liquid and produced foamate. As
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can be seen in Fig. 8, the maximum separation was at gas flowrate of 1 L/min (0.009 m/s). It can be observed that at high gas flowrate, above 1.5 L/min, the separation efficiency was dramatically decreased. This is maybe because increasing gas flowrate increased the turbulence
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in the solution to the limit that disrupts the foam formation. Also this deteriorating of separation efficiency can be due to the decrease of the contact time between the bubbles and the corrosion inhibitor as a result of the increase in gas flowrate. The gas flowrate of 1 L/min (0.009 m/s) shows the biggest difference in surface tension between the remaining liquid and produced foamate and thus it was used as optimum air flowrate to investigate the effect of the other
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operating parameters.
Table 3. Effect of gas flowrate on the surface tension of the remaining liquid and produced foamate of 150 mL of 50 wt% MDEA solution with 250 ppm of corrosion inhibitor. Liquid Surface Tension (mN/m)
Difference in Surface Tension
0.004 0.009 0.013 0.018 0.022 0.026
44.98 46.54 43.36 48.38 47.86 48.74
47.6 49.82 46.34 48.04 47.48 48.74
2.62 3.28 2.98 -0.34 -0.38 0
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0.5 1 1.5 2 2.5 3
Foamate Surface Tension (mN/m)
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Air Flowrate (L/min)
Super facial velocity (m/s)
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Fig. 8. Effect of air flowrate on the separation efficiency, in term of the difference between the surface tension in the remaining liquid and produced foamate for 150 ml of 50 wt% MDEA with 250 ppm corrosion inhibitor. 3.2.4 Effect of foamate collecting time
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The effect of foamate collecting time was studied by varying the sampling time from 0.0 to 20 min for 150 mL of 50 wt% MDEA solution and 250 ppm of corrosion inhibitor using an air flowrate of 1 L/min. The surface tension of the remaining liquid and produced foamate is shown in Table 4. It was observed that the optimum foamate collection time is at 5 min from starting the
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experiment as shown in Fig. 9. This observation may be explained by the two following hypothesis: For very short time less than 5 min, the contact time between the gas bubbles and the
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corrosion inhibitor will not be enough to reach the maximum surface adsorption and thus the separation efficiency will not be the greatest. For longer time more than 5 min, the foam bubbles breaking will increase lead to loss of corrosion inhibitor from the foamate and higher mixing between the liquid and the foamate thus less difference in surface tension. Also long time will be sufficient to reach the critical micelles concentration (CMC) and thus the corrosion inhibitor will start to aggregate in micelles and back to the MDEA solution.
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Table 4. Effect of foamate collecting time on the surface tension of the remaining liquid and produced foamate for 150 mL of 50 wt% MDEA solution and 250 ppm of corrosion inhibitor using air flowrate of 1 L/min Liquid Surface Tension (mN/m) 52.3 51.74 52.14 50.54 49.48
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Foamate Surface Tension (mN/m) 47.74 43.24 48.08 46.64 44.86
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Foam collecting Time (mins) 0 5 10 15 20
Fig. 9. Effect of foamate collecting time on the separation efficiency, in term of the difference between the surface tension in the remaining liquid and produced foamate for 150 mL of 50 wt% MDEA solution and 250 ppm of corrosion inhibitor using air flowrate of 1 L/min
4. Conclusion The effect of the addition of industrial corrosion inhibitor on foaming behavior of 50 wt% MDEA was studied. Then, the effects of operating parameters i.e. foamate collecting time, dispersion gas flowrate, initial liquid volume, and initial corrosion inhibitor concentration on
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foam fractionation separation efficiency were investigated. It was found that increasing the concentration of the corrosion inhibitor increased the foam breaking time and volume. Increase initial liquid volume inversely affected the extent of separation due to the increase in foam wetness. The maximum separation was at gas flowrate of 1 L/min (0.007 m/s). It was observed
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that at high gas flowrates, above 1.5 L/min, the separation efficiency dramatically decreased. It was observed that the optimum foamate collection time is at 5 min from starting the experiment. These experimental observations can help to design more efficient foam fractionation unit for
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cleaning purposes of amine solution in industrial gas sweetening processes.
Acknowledgments funding the project (GRC006).
References
4.
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7. 8. 9. 10.
11.
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Pauley, C.R., Face the facts about amine foaming. Chemical Engineering Progress, 1991. 87(7): p. 33-38. Lemlich, R., CHAPTER 3 - PRINCIPLES OF FOAM FRACTIONATION AND DRAINAGE, in Adsorptive Bubble Separation Techniques, R. Lemlich, Editor 1972, Academic Press. p. 33-51. Li, R., et al., Pilot study of recovery of whey soy proteins from soy whey wastewater using batch foam fractionation. Journal of Food Engineering, 2014. 142(0): p. 201-209. Davis, D.A., H.C. Lynch, and J. Varley, The application of foaming for the recovery of Surfactin from B. subtilis ATCC 21332 cultures. Enzyme and Microbial Technology, 2001. 28(4–5): p. 346354. Rujirawanich, V., et al., Recovery of surfactant from an aqueous solution using continuous multistage foam fractionation: Influence of design parameters. Chemical Engineering and Processing: Process Intensification, 2012. 52(0): p. 41-46. Rangarajan, V. and R. Sen, An inexpensive strategy for facilitated recovery of metals and fermentation products by foam fractionation process. Colloids and Surfaces B: Biointerfaces, 2013. 104(0): p. 99-106. Wall, D., Advanced Chemical Separation Using Foam Fractionation, in Mansfield College2007, Oxford. Phul, S.A.V. Sweetening process foaming and abatement. in Laurance Reid Gas Conditioning Conference. 2001. (ASTM), A.S.f.T.a.M., ASTM D892- Standard Test Method for Foaming Characteristics of Lubricating Oil, 1999, ASTM: West Conshohocken, PA. Chen, X., S.A. Freeman, and G.T. Rochelle, Foaming of aqueous piperazine and monoethanolamine for CO2 capture. International Journal of Greenhouse Gas Control, 2011. 5(2): p. 381-386. Pauley, C.R., R. Hashemi, and S. Caothien, Analysis of Foaming Mechanisms in Amine Plants, P. Corporation, Editor 1988, American Institute of Chemical Engineer.
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The authors are grateful to the Gas Research Centre at The Petroleum Institute in Abu Dhabi for
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13.
Alhseinat, E., et al., Effect of MDEA degradation products on foaming behavior and physical properties of aqueous MDEA solutions. International Journal of Greenhouse Gas Control, 2015. 37(0): p. 280-286. Alhseinat, E., et al., Foaming study combined with physical characterization of aqueous MDEA gas sweetening solutions. Journal of Natural Gas Science and Engineering, 2014. 17(0): p. 49-57. Thitakamol, B. and A. Veawab, Foaming behavior in CO2 absorption process using aqueous solutions of single and blended alkanolamines. Industrial and Engineering Chemistry Research, 2008. 47(1): p. 216-225. Thitakamol, B. and A. Veawab, Foaming model for CO2 absorption process using aqueous monoethanolamine solutions. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2009. 349(1–3): p. 125-136. Wilson, A., Foams: Physics, Chemistry and Structure; Springer-Verlag1989, London, Great Britain: Springer-Verlag.
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Removal of MDEA Foam Creators Using Foam Fractionation: Parametric Study coupled with Foam Characterization Emad Alhseinata*, Mahmoud Amrb , Rami Jumahb, Fawzi Banata of Chemical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi, United Arab Emirates b Department of Chemical Engineering, Jordan University of Science and Technology, Irbid, Jordan * Corresponding author: P.O Box 2533, Abu Dhabi, UAE E-mail address: [email protected]
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Foam fractionation as a potential technique for contaminants removal from Methyldiethanolamine (MDEA) solutions was investigated. The effect of process parameters on foam fractionation performance was studied. Industrial corrosion inhibitor was added as model contaminant and foam creator in gas sweetening units. Foam fractionation was capable for separating and concentrating surface active contaminates into the foamate.
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