Burning Through the Confusion: See How Combustion IC ......Burning Through the Confusion: See How...

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

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193 Better Surfactant Analysis and a New Approach for Cloud Point

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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

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