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Burning Through the Confusion:See How Combustion IC Provides Superior Halide Analysis
Jay ShefferMetrohm USAWednesday, October 17, 2018
Gulf Coast ConferenceAbstract # 187
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 hydro-
treating 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
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
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
Method Confusion???
Combustion IC
Precision: Original D4929 - Methods A & B
• Test Method A(Sodium biphenyl reduction, potentiometry)
r = 0.32 ( X + 0.33)0.644
R = 0.7 ( X + 0.33)0.644
• Test Method B(Combustion, microcoulometry)
r = 1.01 ( X – 0.17)0.467
R = 1.32 ( X – 0.17)0.4670
1
2
3
4
5
6
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Std
Dev
Cl in Crude Conc
Method A and B: repeatability and Reproducibility
Method A r
Method A R
Method B r
Method B R
Data from ILS reports for D4929 and D8150 development and available from ASTM
0
1
2
3
0 1 2 3 4 5
Std
Dev
Cl in Crude Conc
D4929 - Methods A and B: repeatability (r) and Reproducibility (R)
Method A r
Method A R
Method B r
Method B R
• Concentrations of chloride < 5ppm is of most importance to industry
• Specifications often dictate organic chloride < 2ppm
Precision: Original D4929 - Methods A & B
Data from ILS reports for D4929 and D8150 development and available from ASTM
Precision: D4929 Method C - XRF
0
0.5
1
1.5
2
2.5
3
0 1 2 3 4 5
Std
Dev
Cl in Crude Conc
Method C: repeatability and Reproducibility
MWDXRF r
MWDXRF R
MEDXRF r
MEDXRF R
EDXRF r
EDXRF R
Data from ILS reports for D4929 and D8150 development and available from ASTM
Precision: D8150 - CIC
0
0.5
1
1.5
2
2.5
3
0 1 2 3 4 5
Std
Dev
Cl in Crude Conc
CIC + XRF + Method A and B: repeatability and Reproducibility
CIC r
CIC R
Data from ILS reports for D4929 and D8150 development and available from ASTM
Comparing Precision of D4929 and D8150
0
0.5
1
1.5
2
2.5
3
0 1 2 3 4 5
Std
Dev
Cl in Crude Conc
CIC + XRF + Method A and B: repeatability and Reproducibility
CIC r
CIC R
MWDXRF r
MWDXRF R
MEDXRF r
MEDXRF R
EDXRF r
EDXRF R
Method A r
Method A R
Method B r
Method B R
Data from ILS reports for D4929 and D8150 development and available from ASTM
Spike Recovery: D8150 - CIC
Sample ID Expected Concentration(Approximate)(mg/kg)
CIC Mean Concentration(mg/kg)
SA 1 1.024
SB 12 11.771
SC 10 8.435
SD 3 3.156
SE 0 (no spike) 0.185
SF 1 1.007
SG 5 4.946
SH 0 (no spike) 0.154
SI 6 4.069
SJ 5 5.076 0
1
2
3
4
5
6
7
0 1 1 2 2 3 3 4 4 5 5
Reco
vere
d Co
ncen
tratio
n, m
g/kg
Cl
Spiked Concentration, mg/kg Cl
Average Recovery of Org Cl Spike by CIC and XRF(multiple samples spiked with 0,1,5ppm were averaged as a single point)
CIC Averaged
Ideal Recovery
13Data from ILS reports for D4929 and D8150 development and available from ASTM
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
Challenges with D4929 Test Method C
• EDXRF, MEDXRF, MWDXRF
• Interference with sulfurS Ka = 2.3 keVS KB = 2.45 keVCl Ka = 2.55 keV• When using Ag anode x-ray tube
(less overlap than Rh or Pd anode tubes)
100ppm Cl + 5,000ppm S interferentHigh Sulfur Crudes = 1ppm Cl + 10,000ppm S interferent
Detection Limits Comparison
• D4929 Test Methods A, B:Cl < 1ppm
• D4929 Test Method C:• EDXRF, MEDXRFCl < 1ppm• MWDXRFCl < 0.13 to 0.3ppm
• D8150 Combustion IC• Cl < 0.1ppm• Can be pushed lower with good techniques
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
• Automated pyrohydrolytic combustion• Heat + Oxygen - Breaks covalent bonds to remove halogens from
organic molecules
Combustion Ion Chromatography (CIC)
• Capable of performing simultaneous determination of sulfur and individual halides in a single run• F, Cl, Br• S (as SO4)
Combustion IC Advantages
Combustion IC Advantages
Column Metrosep A Supp 5 150 x 4.0mm
Eluent3.2mmol/L Na2CO3+1.0 mmol/L NaHCO3
Eluent flow 0.7mL/min
Combustion temperature 1050°C
Combustion volume 100µL
Absorption solution Ultra-pure water
Injection volume 200µL
Detector Suppressed Conductivity
Cl
SO4-2
ASTM D8150 - CIC
Component Name
Retention Time[min]
Organic Chloride Concentration Naphtha[mg/kg]
OrganicChlorideConcentration Crude[mg/kg]
Chloride 6.40 12.037 2.923
Unwashed Naphtha Distillate
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
Metrohm at GCC 2018
Abstract # Title Time
251 Simple, Efficient Petrochemical Analysis with NIR and Raman Spectroscopy
10:30am – 11:00am
193 Better Surfactant Analysis and a New Approach for Cloud Point
1:30pm – 2:00pm
194 Robotic Titration for Consolidating Petrochemical Titrations 2:00pm – 2:30pm
Technical Presentations: Wednesday 10/17, Wysteria
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
Technical Posters: Wednesday 10/17, South Lobby
Metrohm at GCC 2018
Titration Ion Chromatography Electrochemistry
Process Monitoring Spectroscopy
Visit Metrohm at Booth #817
