Determinations of Heat Stable Amine Salts and Amines in Amine Scrubbing Solutions Using Suppressed Conductivity and Charge Detection

Transcription

1 Determinations of Heat Stable mine Salts and mines in mine Scrubbing Solutions Using Suppressed Conductivity and Charge Detection Terri Christison, Monika Verma, Pranathi Perati, Linda Lopez Thermo Fisher Scientific, Sunnyvale, C, US

2 Overview Results Heat stable amine (HS) salts, such as organic acids, inorganic anions, and sulfur based salts, in amine scrubber solutions were separated by anion-exchange on a µm particle high-efficiency capillary column. Charge Detection This method utilizes two different but complementary detectors, suppressed conductivity and charge detection. Charge detection provides higher relative responses for multi-charged anions, such as found in heat stable amine salt solutions, than chloride and sulfate. Using these two detectors with different responses were used to confirm peak purity and the presence of co-eluting peaks, thereby improving reporting accuracy. The Dionex QD Ch dissociated compo the charge respon proportionally high FIGURE. Mecha. Introduction n Sour crude natural gas (methane) is typically treated with amine rich scrubber solutions to neutralize carbon dioxide and remove hydrogen sulfide gas impurities before it can be sold as a pure natural gas product., When the neutralizing capacity is deemed inefficient, the amine solutions are regenerated and stripped of elemental sulfur. Dissolved salts (heat stable amine salts) remain, building up over time resulting in higher maintenance costs, and higher incidents of corrosion., nalysis of both the amine concentrations and the heat stable amine salts are needed to ensure a pure product and an efficient scrubbing process. The Thermo Scientific Dionex QD Charge Detector promotes complete dissociation of many weakly dissociated compounds as a result, the charge responses of singlycharged, doubly-charged, and triply-charged ions are proportionally higher than conductivity. CD and QD detector provided different responses were used to confirm peak identity and the presence of unknown co-eluting peaks. Methods Figures 5 demon used for improved Figure shows an detection (R) whic and R) clearly def Samples / Sample Preparation Sour gas amine samples were diluted -fold with deionized water. Some amine samples were treated with Thermo Scientific Dionex OnGuard II RP and Dionex OnGuard II Na cartridges to remove interfering cations and organic compounds. Figure 5 illustrates C concentrations concentration. Instrumentation FIGURE. Using Thermo system. Scientific Dionex ICS-5+ HPIC Ion Chromatography dual capillary Example : QD co DP Dual Pump, EG Eluent Generator, DC Detector Chromatography, and Thermo Scientific Dionex IC Cube modules Thermo Scientific Dionex Detectors: CD Conductivity Detector, QD Charge Detector with Thermo Scientific Dionex QDC Cell utosampler: Thermo Scientific Dionex S-P utosampler Data nalysis: Thermo Scientific Dionex Chromeleon Chromatography Data System Conditions: Thermo Scientific Dionex IonPac GHC-µm, Dionex IonPac SHC-µm,. 5 mm Eluent Source: Thermo Scientific Dionex EGC KOH cartridge, capillary mm KOH (-7 8 min), mm (8 8 min), 85 mm (8 8 min), 85 mm (8 5 min) Flow Rate:.5 ml/min Column Temp.: C Inj. Volume:. µl : Suppressed conductivity, Thermo Scientific Dionex CES nion Capillary Eleyctolytic Suppressor, recycle mode; m : Charge detection, Dionex QDC cell, 6 V Stable mine Salts diagram and minesfor in mine Scrubbing Solutions Using Conductivity and Charge Detection Determinations of Heat FIGURE. Flow the IC system using CDSuppressed and QD detectors. FIGURE 5. Using Example : CD co

3 Thermo Scientific Dionex Detectors: CD Conductivity Detector, QD Charge Detector with Thermo Scientific Dionex QDC Cell utosampler: Thermo Scientific Dionex S-P utosampler Data nalysis: Thermo Scientific Dionex Chromeleon Chromatography Data System Conditions: Thermo Scientific Dionex IonPac GHC-µm, Dionex IonPac SHC-µm,. 5 mm Eluent Source: Thermo Scientific Dionex EGC KOH cartridge, capillary mm KOH (-7 8 min), mm (8 8 min), 85 mm (8 8 min), 85 mm (8 5 min) Flow Rate:.5 ml/min Column Temp.: C Inj. Volume:. µl : Suppressed conductivity, Thermo Scientific Dionex CES nion Capillary Eleyctolytic Suppressor, recycle mode; m : Charge detection, Dionex QDC cell, 6 V FIGURE. Flow diagram for the IC system using CD and QD detectors. FIGURE 5. Using C Example : CD co H High-Pressure Non-Metallic Pump Eluent Generator (OH ) Data Management Charge Detector Separation Column CR-TC Waste Electrolytic Eluent Suppressor Conductivity Detector Figure shows the Dionex IC Cube module and Dionex QDC Charge Detector cell. The Dionex IC Cube is designed to minimize the flow path needed for a capillary flow rate system by containing the columns and consumables in close proximity.. FIGURE. Dionex IC Cube with capillary modules Thermo Scientific Dionex CRD 8 Carbonate Removal Device cartridge Dionex CES Suppressor Dionex Conductivity Detector (CD) Figure 6 shows the acids, and sulfur-b were normalized to which are triply charged nitrite. Th response when no FIGURE 6. Separ Guard and Separation Column tray Dionex IC Cube -Port Injection Valve Thermo Scientific Dionex Degas cartridge Dionex QDC Charge Detector Cell -.5 Thermo Scientific Poster Note PN78_HPLC E_5/S

4 Results ons, and sulfur xchange on a µm pressed relative mine salt solutions, nfirm peak purity ccuracy. Charge Detection The Dionex QD Charge Detector promotes complete dissociation of many weakly dissociated compounds by drawing a current at a fixed potential (Figure ). s a result, the charge responses of singly-charged, doubly-charged, and triply-charged ions are proportionally higher than conductivity. FIGURE. Mechanism of QD Charged Detector FIGURE 7 8: n. crubber solutions es before it can be s deemed tal sulfur. resulting in higher th the amine pure product and ete dissociation of es of singlygher than sed to confirm ome amine RP and Dionex mpounds. 6V Cathode node H FIGURE 7: CD v Y- + + Y- 5 + H 5 6 nion-exchange Membrane Cation-Exchange Membrane Figures 5 demonstrate how the different peak responses by the CD and QD can be used for improved data analysis. Figure shows an example where the peaks have with the same response by CD detection (R) which could be either C or C concentrations; but with QD detection (R and R) clearly defines the concentrations. Figure 5 illustrates another example were QD detection (R) correspond to both C and C concentrations but is clarified by CD detection where R and R confirm C concentration. FIGURE. Using CD and QD detection for peak analysis. ual capillary Figures 7 9 show neutralizing sam was pretreated w compounds and Dionex sample p without introduci QD chromatgram comparison. In F boxes) not notice M Figure 9 show th contamination, s FIGURE 9. 6 Example : QD confirmation. phy, and Thermo CD QD Charge Detector QD or R R R -.5 tem C C C C C-µm, Conclusio capillary 85 mm FIGURE 5. Using CD and QD detection for peak analysis. Example : CD confirmation. Dionex essor, recycle QD R CD or Determinations of Heat Stable mine Salts and mines in mine Scrubbing Solutions Using Suppressed Conductivity and Charge Detection R ors. R Heat stable am organic acids Here we demo stable amine s This method h capillary-size (HPIC) capilla Using differen

5 Conclusion pillary 85 mm FIGURE 5. Using CD and QD detection for peak analysis. Detector cell. pillary flow y. QD This method has capillary-size Dio (HPIC) capillary or R R CD R s. ty Here we demon stable amine sal Example : CD confirmation. Dionex sor, recycle rge Detector Heat stable amin organic acids an C C Using different d detector provide result in improve References C C Figure 6 shows the separation of a standard containing 5 inorganic anions, organic acids, and sulfur-based anions typically found as heat stable amine salts. QD responses were normalized to the nitrite peak. Peak which is doubly charged and Peaks and which are triply charged have higher QD response than strongly ionized singlely charged nitrite. Thiocyanate is a singly charged ion which had a comparable relative response when normalized to nitrite. FIGURE 6. Separation of mixed standard using CD and QD detection Cube 8 Scientific egas µ C tector Cell Minutes 5 Dionex IonPac S-HC-µm with guard Capillary (. 5 mm,. 5 mm) Eluent Source: Dionex, EGC-KOH (Capillary) cartridge Potassium hydroxide mm (-7 8 min), mm (8 8 min), 85 mm (8 8 min), 85 mm (8 5 min) Flow Rate:.5 ml/min Inj. Volume:. µl Column Temp.: C : Suppressed conductivity, Dionex CES suppressor, recycle mode : Dionex QD Charge Detection, 6 V Sample Prep.:. Natural Gas.or. Rooney, P.C.; Corrosivity, Pa Thermo Fisher in Methyldietha Sunnyvale, C lication%&% and%rfi Methyldiethano Peaks:. Fluoride. mg/l 9. Carbonate. cetate.. Sulfite. Propionate.. Sulfate*. Formate.. Oxalate 5. Chloride*. Phosphate 6. Nitrite.. Thiosulfate 7. romide. 5. Thiocyanate 8. Nitrate mg/l ll trademarks are the This information is no the intellectual proper * CD response for chloride and sulfate was truncated at. QD chromatogram was normalized at the nitrite peak. Thermo Scientific Poster Note PN78_HPLC E_5/S 5

6 y weakly ). s a result, ged ions are Figures 7 9 show the determination of heat stable amine salts (HS) in amine neutralizing samples. Prior to injection, the diluted scrubber sample in Figures 7 and 8 was pretreated with Dionex OnGuard RP and Dionex OnGuard Na to remove organic compounds and cation contaminants that were affecting the chromatography. These Dionex sample preparation cartridges are designed to remove select contaminants without introducing IC-detectable ionic contaminants. In Figure 7, the chloride peak in the QD chromatgram was normalized to the same peak in the CD chromatogram for easier comparison. In Figure 8, an expanded QD chromatogram reveals additional peaks (in boxes) not noticeable by CD, thereby providing additional information and peak purity. FIGURE 7 8: nion determinations in -fold diluted amine scrubber solution. FIGURE 7: CD versus QD FIGURE 8: Expanded scale of QD detection. dditional peaks are revealed µ d QD can be Minutes *oxes denote detection of additional peaks se by CD D detection (R o both C and rm C µ 8 6 Conditions:: see Figure 6. : Suppressed conductivity, Dionex CES suppressor, recycle mode : QD Charge Detection, 6 V Sample Prep.: -fold dilution with deionized water, Dionex OnGuard RP and OnGuard Na treatment Peaks (mg/l):. cetate 9. Propionate.8. Formate. Unknown -5. Chloride.9 6. Unknown -7. Carbonate -8. Sulfate.9 9. Oxalate. Unknown. Phosphate. Thiosulfate. Thiocyanate * QD was normalized to the chloride peak Figure 9 show the CD and QD chromatograms of an amine solution with less HS contamination, sampled at an overhead actuator. FIGURE 9. -fold Dilution of an amine solution from an overhead actuator µ Minutes 5 Dionex IonPac S-HC-µm with guard Capillary (. 5 mm,. 5 mm) Eluent Source: Dionex EGC-KOH (Capillary) cartridge Potassium hydroxide, mm (-7 8 min), mm (8 8 min), 85 mm (8 8 min), 85 mm (8 5 min) Flow Rate:.5 ml/min Inj. Volume:. µl Column Temp.: C : Suppressed conductivity, Dionex CES suppressor, recycle mode : QD Charge Detection, 6 V Sample Prep.: Diluted -fold with deionized water Peaks:. cetate. Carbonate. Sulfite. Sulfate 5. Thiosulfate mg/l * QD was normalized to the sulfate peak Conclusion Heat stable amine salts are challenging samples for analysis with many sulfur species, organic acids and high concentrations of inorganic anions. Here we demonstrated an IC method needed by the gas industry to analyze heat stable amine salts in amines samples. This method has high efficiency separations made possible on a µm particle capillary-size Dionex IonPac S-HC-µm column and facilitated by a high-pressure (HPIC) capillary IC system. 6 Determinations of Heat Stable mine Salts and mines in mine Scrubbing Solutions Using Suppressed Conductivity and Charge Detection Using different detectors, such as the CD conductivity detector and the QD charge

7 . Sulfate 5. Thiosulfate * QD was normalized to the sulfate peak Conclusion Heat stable amine salts are challenging samples for analysis with many sulfur species, organic acids and high concentrations of inorganic anions. Here we demonstrated an IC method needed by the gas industry to analyze heat stable amine salts in amines samples. This method has high efficiency separations made possible on a µm particle capillary-size Dionex IonPac S-HC-µm column and facilitated by a high-pressure (HPIC) capillary IC system. Using different detectors, such as the CD conductivity detector and the QD charge detector provide advantages in improved peak identification and peak detection which result in improved reporting accuracy and information. References ons, organic s. QD responses d Peaks and zed singlely able relative n. Natural Gas.org Home Page. (accessed pril 7, ).. Rooney, P.C.; acon, T.R.; DuPart, M.S. Effect of Heat Stable Salts on MDE Corrosivity, Parts and. Hydrocarbon Processing, 996, Mar, 95 ; 997, pr, Thermo Fisher Scientific Technical Note : Separation of Heat Stable mine Salts in Methyldiethanolamine (MDE) Solutions. Thermo Scientific P/N TN79_E, Sunnyvale, C,. [Online] lication%&%technical%notes/chromatography/ion%chromatography/ic% and%rfic%systems/tn--separation-heat-stable-mine-saltsmethyldiethanolamine-solutions-tn79-e.pdf (accessed pril 7, ). S-HC-µm with guard 5 mm,. 5 mm) KOH (Capillary) cartridge droxide n), mm (8 8 min), 8 min), min) d conductivity, suppressor, recycle Charge Detection, 6 V arbonate lfite lfate* alate osphate iosulfate iocyanate mg/l ll trademarks are the property of Thermo Fisher Scientific and its subsidiaries. This information is not intended to encourage use of these products in any manners that might infringe the intellectual property rights of others. d sulfate was truncated was normalized at the nitrite PO78_E 5/S Thermo Fisher Scientific Inc. ll rights reserved. ISO is a trademark of the International Standards Organization. ll other trademarks are the property of Thermo Fisher Scientific Inc. and its subsidiaries. This information is presented as an example of the capabilities of Thermo Fisher Scientific Inc. products. It is not intended to encourage use of these products in any manners that might infringe the intellectual property rights of others. Specifications, terms and pricing are subject to change. Not all products are available in all countries. Please consult your local sales representative for details. frica + 5 ustralia ustria elgium razil Canada China (free call domestic) Denmark Europe-Other + 5 Finland France Germany India Italy Japan Korea Latin merica Middle East + 5 Netherlands New Zealand Norway Thermo Fisher Scientific, Sunnyvale, C US is ISO 9:8 Certified. Russia/CIS + 5 Singapore Sweden Switzerland Taiwan UK/Ireland US PN78_E 5/S