Burning Through the Confusion: See How Combustion IC Provides Superior Halide Analysis

Transcription

1 Burning Through the Confusion: See How Combustion IC Provides Superior Halide Analysis Jay Sheffer Metrohm USA Wednesday, October 17, 2018 Gulf Coast Conference Abstract # 187

2 Organic Halides in Crude Rarely occur naturally in crude oils Introduced at production sites, pipelines, or tanks in cleaning operations Produce HCl, HF, etc., in reforming and hydrotreating processes Leads to corrosion and catalyst poisoning Speciation of halides is important to trace the contamination source. Current specifications expect < 2ppm org Cl in crude oil Detection at low levels (< 5ppm) is of most importance to industry

3 Recent ASTM Development New methodology was developed in ASTM D02 for additional testing methodologies for organic chloride in crude: 1) Updated ASTM D4929: organic chloride measurement in crude oil by distillation and XRF detection (new Procedure C) 2) New ASTM D8150: organic chloride measurement in crude oil by distillation and Combustion IC detection

4 Development of ASTM D4929 and D8150 Test methods consist of: Distillation to 400ºF Water wash (removes inorganic chloride) Caustic wash (removes sulfur) Detection by: 1) D4929-Test Method A: Sodium biphenyl reduction and potentiometry, or 2) D4929-Test Method B: Combustion and microcoulometry, or 3) D4929-Test Method C: X-ray fluorescence spectroscopy (including MWDXRF, MEDXRF, and EDXRF) 4) D8150-Test Method: Combustion Ion Chromatography

5 Method Confusion??? Combustion IC

6 Data from ILS reports for D4929 and D8150 development and available from ASTM Precision: Original D Methods A & B Test Method A (Sodium biphenyl reduction, potentiometry) r = 0.32 ( X ) R = 0.7 ( X ) Method A and B: repeatability and Reproducibility Test Method B (Combustion, microcoulometry) r = 1.01 ( X 0.17) Std Dev Method A r Method A R Method B r Method B R R = 1.32 ( X 0.17) Cl in Crude Conc

7 Precision: Original D Methods A & B D Methods A and B: repeatability (r) and Reproducibility (R) Concentrations of chloride < 5ppm is of most importance to industry Specifications often dictate organic chloride < 2ppm Std Dev Method A r Method A R Method B r Method B R Cl in Crude Conc Data from ILS reports for D4929 and D8150 development and available from ASTM

8 Data from ILS reports for D4929 and D8150 development and available from ASTM Precision: D4929 Method C - XRF 3 Method C: repeatability and Reproducibility Std Dev 1.5 MWDXRF r MWDXRF R MEDXRF r MEDXRF R 1 EDXRF r EDXRF R Cl in Crude Conc

9 Data from ILS reports for D4929 and D8150 development and available from ASTM Precision: D CIC 3 CIC + XRF + Method A and B: repeatability and Reproducibility Std Dev 1.5 CIC r CIC R Cl in Crude Conc

10 Data from ILS reports for D4929 and D8150 development and available from ASTM Comparing Precision of D4929 and D CIC + XRF + Method A and B: repeatability and Reproducibility 2.5 CIC r 2 Std Dev 1.5 CIC R MWDXRF r MWDXRF R MEDXRF r MEDXRF R EDXRF r 1 EDXRF R Method A r Method A R Method B r 0.5 Method B R Cl in Crude Conc

11 13 Spike Recovery: D CIC Sample ID Expected Concentration (Approximate) (mg/kg) CIC Mean Concentration (mg/kg) 7 Average Recovery of Org Cl Spike by CIC and XRF (multiple samples spiked with 0,1,5ppm were averaged as a single point) SA SB SC SD SE 0 (no spike) SF SG SH 0 (no spike) SI Recovered Concentration, mg/kg Cl CIC Averaged Ideal Recovery SJ Spiked Concentration, mg/kg Cl

12 Challenges with D4929 Test Methods A and B Sodium biphenyl reduction and potentiometry Combustion and microcoulometry Interference from other titratable halides including HBr and HI Interference with oxyhalides HOBr and HOI Detection limit of 1ppm Cl

13 Challenges with D4929 Test Method C EDXRF, MEDXRF, MWDXRF Interference with sulfur S Ka = 2.3 kev S KB = 2.45 kev Cl Ka = 2.55 kev When using Ag anode x-ray tube (less overlap than Rh or Pd anode tubes) 100ppm Cl + 5,000ppm S interferent High Sulfur Crudes = 1ppm Cl + 10,000ppm S interferent

14 Detection Limits Comparison D4929 Test Methods A, B: Cl < 1ppm D4929 Test Method C: EDXRF, MEDXRF Cl < 1ppm MWDXRF Cl < 0.13 to 0.3ppm D8150 Combustion IC Cl < 0.1ppm Can be pushed lower with good techniques

15 Combustion IC Advantages Determination of chloride without interference from other species Determination of individual halides and sulfur in one sample run No need to remove sulfur (eliminating caustic wash) Determine total, individual halides including organic and inorganic sources (without water wash) Determine organic, individual halides (with water wash) Allows more flexibility with your analysis

16 Combustion Ion Chromatography (CIC) Automated pyrohydrolytic combustion Heat + Oxygen - Breaks covalent bonds to remove halogens from organic molecules

17 Combustion IC Advantages Capable of performing simultaneous determination of sulfur and individual halides in a single run F, Cl, Br S (as SO 4 )

18 Combustion IC Advantages ASTM D CIC Column Metrosep A Supp x 4.0mm Eluent 3.2mmol/L Na2CO mmol/l NaHCO3 Eluent flow 0.7mL/min Combustion temperature 1050 C Combustion volume 100µL Unwashed Naphtha Distillate Cl SO 4-2 Absorption solution Ultra-pure water Injection volume 200µL Detector Suppressed Conductivity Component Name Retention Time [min] Organic Chloride Concentration Naphtha [mg/kg] Organic Chloride Concentration Crude [mg/kg] Chloride

19 Summary Combustion Ion Chromatography demonstrates superior performance, selectivity, sensitivity, and lack of interferences. Able to determine individual concentrations of halides and sulfur in a variety of matrices Permits refineries to control corrosion and associated costs by predicting, locating, and preventing it Becoming widely accepted with several new methods under development in ASTM

20 Metrohm at GCC 2018 Technical Presentations: Wednesday 10/17, Wysteria Abstract # Title Time 251 Simple, Efficient Petrochemical Analysis with NIR and Raman Spectroscopy 193 Better Surfactant Analysis and a New Approach for Cloud Point 10:30am 11:00am 1:30pm 2:00pm 194 Robotic Titration for Consolidating Petrochemical Titrations 2:00pm 2:30pm

21 Metrohm at GCC 2018 Technical Posters: Wednesday 10/17, South Lobby Abstract # Title Time 196 OMNIS: Titration for Faster, Safer and Easier Analysis 10:00am 12:30pm 1976 Acid Number of Crude Oils and Petroleum Products by Catalytic Thermometric Titration using ASTM D8045 1:30pm 4:00pm

22 Visit Metrohm at Booth #817 Titration Ion Chromatography Electrochemistry Process Monitoring Spectroscopy