Combatting Corrosion in Refineries:Using Ion Exchange Chromatography to Measure Free Cyanide in Sour Water

Jay Sheffer, Jay Gandhi

Metrohm USA

Tuesday, October 16, 2018

Gulf Coast Conference

Abstract # 186

2

•An interesting view of a

refinery’s purpose…

“Process or generate as much

product as possible from a

refinery before it all falls down.”

- unknown

Much Ado About Corrosion

3

•Corrosion is of great concern to

refineries and industry

Costs ~ $4 billion annually

•Halides, sulfur, cyanide in

feedstocks and products break

down to form acids

Corrosive to refinery, equipment, and

engines

Corrosive species include: fluoride,

chloride, sulfur, cyanide

Concerns for Corrosion

4

Crude Refinement

5

Crude Refinement

• Desalting• Desulfurization

(Sour Water Stripping)

Why?

Prevent corrosion

Sour Water Stripping

Refinery PAT

• Steam Stripping Process

Sour Water Stripping

Refinery PAT

• Parameters of Interest• Sulfide

• Ammonia

• Phenol

• Cyanide

• Parameters of Interest• Sulfide

• Ammonia

• Phenol

• Cyanide• pH

• Conductivity

• Alkalinity & Hardness

HCN/CN- is very corrosive

https://scindeks-clanci.ceon.rs/data/pdf/0042-8469/2016/0042-84691604048P.pdf

• 930 Compact IC Flex - Cation

• A SUPP 10 250mm x 4mm column

• A SUPP 10 Guard/4.0 guard

• Anion-exchange column

• Eluent: 100mM NaOH + 0.01mM Na2EDTA

• Flow: 0.8mL/min

• Column temperature: 45°C

• Sample loop: 20mL

• 858 ProfIC Sample Processor

Cyanide by Ion Exchange Chromatography

2.930.2160

Compact IC Flex Oven/Deg2.858.0020

ProfIC Sample Processor

•Amperometric detection• Ag working electrode

• Pd solid-state reference electrode

• Mode: direct current (DC), 0.0 volts

• Detector temperature: 40°C

Cyanide by Ion Exclusion Chromatography

2.850.9110

Amperometric Detector

11

Calibration standards

• Standards were prepared in ppb

range to accommodate sample

dilution (1:1000)

Standard CN- (mg/L)

# 1 2.5 ppb

# 2 5.0 ppb

# 3 10.0 ppb

# 4 32.5 ppb

# 5 50 ppb

Correlation 0.99986

RSD (%) 1.804 %

Cyanide (CN-)

Calibration Plot

AW IC US6-0257-022018

Calibration Standards

A SUPP 10 250mm x 4mm column

A SUPP 10 Guard/4.0 guard

Eluent: 100mM NaOH + 0.01mM Na2EDTA

Flow: 0.8mL/min

Column temperature: 45°C

Sample loop: 20mL

Overlay of Calibration Standards

2.5ppb to 50ppb

Cyanide

AW IC US6-0257-022018

No Interference with Sulfide Matrix

• Some methods encounter sulfide interference

• Flow-injection analyzers (FIA)

• Other techniques require sulfide removal using toxic salts

1) Precipitation with Pd, Cd, or other heavy metals

• Produces additional toxic waste streams

2) Centrifugation

3) Filtration

Sulfide is easily separated with ion chromatography

No sample prep required

AW IC US6-0257-022018

No Interference with Sulfide Matrix

Sample:

• 3% sulfide matrix

• Cyanide = 12ppm

Sample + spike:

• 3% sulfide matrix

• Cyanide = 12ppm

+ 10ppm CN- spike

AW IC US6-0257-022018

Cyanide, ppm

(Sample)

Cyanide, ppm

(Sample + spike)

Recovery

%

Replicate 1 0 1.73 86.5

Replicate 2 0 1.78 89.0

Replicate 3 0 1.79 89.5

Replicate 4 0 1.82 91.0

Replicate 5 0 1.77 88.5

Replicate 6 0 1.85 92.5

Average - 1.79 89.5

Std Dev. - 0.0415 -

Results – Spike Recovery

Low-level spike

Spike = 2.0ppm cyanide

Cyanide, ppm

(Sample)

Cyanide, ppm

(Sample + spike)

Recovery

%

Replicate 1 12.1 22.3 109

Replicate 2 12.1 21.9 104

Replicate 3 12.1 22.8 114

Replicate 4 12.1 22.1 106

Replicate 5 12.1 23.1 117

Replicate 6 12.1 21.8 103

Average - 22.3 109

Std Dev. - 0.516 -

Spike = 9.4ppm cyanide

High-level spike

AW IC US6-0257-022018

Summary

• Ion chromatography provides simple and reliable

measurements of cyanide in sour water

No interference from 3% sulfide matrix

No sample preparation is required; therefore, no

additional toxic waste is generated nor requires

disposal

High-capacity anion exchange column readily

separates sulfide from cyanide

Cyanide detection down to 2ppm

Metrohm at GCC 2018

Abstract # Title Time

188 Simple, Efficient Petrochemical Analysis with NIR and Raman

Spectroscopy

10:30am – 11:00am

190 Fast Hydroxyl Number Analysis 1:30pm – 2:00pm

191 Moisture Analysis of Solids, Liquids, and Gases 2:00pm – 2:30pm

Technical Presentations: Tuesday 10/16, Wysteria

Metrohm at GCC 2018

Abstract # Title Time

187 Burning Through the Confusion: See How Combustion IC

Provides Superior Halide Analysis

10:00am – 10:30am

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

Metrohm at GCC 2018

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

Titration Ion Chromatography Electrochemistry

Process Monitoring Spectroscopy

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