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1 Challenges in Opportunity Crude Processing 16 th April 2012 Thomas Lu Industry Development Manager Asia Pacific Overview Opportunity Crude Trends (High TAN Crude) and its challenges Overview of Factors Affecting Corrosion

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1

Challenges in Opportunity Crude Processing

16th April 2012

Thomas Lu

Industry Development Manager Asia Pacific

Overview

  • Opportunity Crude Trends

(High TAN Crude) and its challenges

  • Overview of Factors Affecting

Corrosion

  • Prevention Methods
  • High Temperature Corrosion

Control

  • Summary
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Opportunity Crude Trends

  • Declining conventional
  • il production
  • Opportunity crude oil

production forecast to grow up to 20% by 2025

  • Extra Heavy (< 22o API) as part of

crude slates (average globally)

Fundamentals

Historic Perspective

  • Problem since 1920s
  • Systematic study since 1950s
  • Chevron published correlation in 1980s
  • Nalco first Scorpion program in 1984
  • Nalco published Sulfidic corrosion phenomenon in

2005

  • Review of 25 years of Scorpion program published

in 2006

4

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What are High Acid Crudes

Crudes with a TAN of 1.0 or higher

5

R CH 2 m C - OH n O

R = Alkyl Groups COOH = Carboxylic Acid CH2 = Alkyl chain

Fundamentals

Measurement

  • TAN = Total Acid Number
  • Two common ASTM methods:
  • D974 (colorimetric- older, used for distillates)
  • D664 (potentiometric- more accurate but measures acid gases, in

addition to organic acids)

  • Differences important on crudes, less significant on distillates)
  • UOP 565 / UOP 587 more applicable
  • Nalco NAT

6

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Will it Cause Corrosion?

 Majority of the challenge crudes on the market are high

acid crudes

  • Total acidity
  • Naphthenic acid content
  • Distribution of acids

 Other species include organic acids, organic chlorides,

undesaltable chlorides, amines, etc.

 Not all TAN is a problem  Measure of naphthenic acid content better gauge

  • f corrosivity

High Temperature Naphthenic Acid Corrosion

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 Distribution can be used to determine likely areas

  • f concern
  • Some newer assays have this TAN data
  • Nalco has a library of high acid crude nap acid

distributions

  • Relative comparison with respect to field experience

Distribution of Acid Corrosivity Testing

Laboratory apparatus

used to simulate temperature and shear stress

Test metallurgy of the

unit

Test inhibitor

effectiveness

2 4 6 8 10 12 14 16 18 Corrosion Rate, MPY C S 5Cr 9C r 410SS Test Sample

Untreated Treated

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Factors Affecting Corrosion

 Vulnerable Locations for

HAC

 Preventative Methods  Other Impacts

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Examples: Vacuum Unit

12

Severe Corrosion on an Outer Bend of an Elbow Just Upstream from the Collection Header

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Examples: Vacuum Bubble Cap Corrosion

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Severe pitting Corrosion of Type 410 Stainless Bubble Cap from a Resid Stripper Column Another View of the Corroded Bubble Cap

Examples: 5 Cr - 1/2 Mo Check Valve in HVGO in Crude Unit

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Factors Effecting Corrosion

Temperature

  • Naphthenic acids concentrate above 450°F (232°C)

boiling range

  • Highest concentration in 600-800°F (316-427°C)

boiling range

  • Lowest temperature where attack occurs ~400°F

(200°C)

  • Lower molecular acids at water condensing locations:

HCOOH ; (CH3)n-COOH

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Factors Effecting Corrosion cont.

Velocity

  • At low velocity, turbulence caused by boiling and

condensing causes attack

  • At high velocity, rapid corrosion can occur
  • Limits well defined for “conventional” crudes

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Naphthenic Acid Corrosion of Carbon Steel

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150 302 200 250 300 350 10 20 30 40 200 390 250 480 300 570 350 660 Temperature, oC (o F)

Corrosion Rate of Carbon Steel at 1.8 - 2.4 TAN

Influence of Linear Velocity on Corrosion Rates in Crude Oil

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Material TAN Linear Velocity, (ft/sec) Corrosion Rates at elbows (mm/yr)

C.S. 1.5 73 12 C.S. 1.5 26 6 5Cr-1/2Mo 1.5 73 2 5Cr-1/2Mo 1.5 26 0.6 9Cr-1Mo 1.5 73 0.7

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Corrosion Rates of Some Alloy Steels During 7 Month Coupon Exposure in a Crude Unit

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Temperature

  • C (oF)

Acid No. C.S. 410SS 304SS 316SS 377 (710) 3+ 48+ 22 0.09 0.06 342 (648) 3.6 49+ 0.5 33 0.08 338 (640) 3.6 48+ 30 30 4.8 300 (570) 4.1 37 5.8 10 0.01

* Corrosion rates shown are MPY; data from literature

Naphthenic Acids - Distillation profile

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Profiles available for many crudes

1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 0 % 1 0 % 2 0 % 3 0 % 4 0 % 5 0 % 6 0 % 7 0 % 8 0 % 9 0 % 1 0 0 % V o lu m e P e r c e n t Temp (deg C)

C e rro Ne g ro (Ve n e z u e la ) D O B A G ra n e D A R P e re g rin o P e tro A n d in a A lb a c o ra

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Prevention Methods

 Blending

  • Typically , blend high TAN with low TAN crude
  • Blending primarily based on desired product mix
  • Metallurgy can become limiting
  • Crude compatibility needs evaluation
  • Sulfur in blend crude may be critical

 Materials Upgrade

  • In mild service, 9 Cr - 1 Mo sometimes adequate
  • Usually 316L (2% Mo) minimum material
  • 317L (3% Mo) often used
  • Structured packing requires 317L min.
  • When chloride stress corrosion cracking (CISCC) is a potential

problem, 2205 or 2507 have been used

  • When high corrosion and/or CISCC are a problem, I625 has

been used

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Prevention Methods cont

Use of Inhibitors

  • Continuous use of high acid crudes (HAC)
  • Successful applications exist for wide range of TAN and NAT
  • Important to maintain monitoring in areas at risk
  • Can be continuous or (depending upon strategy) until

metallurgy is upgraded.

  • Intermittent use of HAC
  • Used when corrosion rates are excessive based on monitoring
  • Cost directly related to amount of equipment

protected

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High Temperature Corrosion Control

SCORPION High Temperature Corrosion Control

  • 25+ Years of Experience
  • >130 HAC Assessments Globally
  • Innovative Monitoring (FSM)
  • Most Comprehensive Chemistries

Best Practice in KM (KM, Downstream, Our Brands, click on SCORPION logo) Step 1. Assessment

Risk Assessment

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Unit / Risk System Description Assessment Line from mix5 to split6 Moderate Line from split6 to furnace 302B control valve manifold. Low Crude to Furnace control valve Low Furnace lines Moderate Line from furnace colector to mix 6 High Line from split6 to mix6 (by-pass) Low Furn.302B to Furn.151B &101B Line from mix6 to split7 Moderate Line from split7 to furnace 101B manifold valve Moderate Manifold lines (inlets 101B) Low 101B Furnace lines convective area Moderate 101B Furnace lines radiation area Moderate Lines from furnace 101B colector to mix7.1 Low Line from mix7.1 to mix7 Low Line from split7 to furnace 151B manifold valve Moderate Manifold lines (inlets 151B) Moderate 151B Furnace lines convective area Moderate 151B Furnace lines radiation area Low Lines from furnace 151B colector to mix7.2 High Line from mix7.2 to mix7 High

Example of Risk Assessment Example of Risk Assessment Risk Assessment

High Acid Crude Assessment Output

SCORPION Inhibitor Injection Location Corrosion Probe Monitoring Location

CP

I

P718 To DCU/Tk 434 U26.1 LVGO 316SS 316SS 316SS HVGO CS 5Cr 545-565°F 385

  • F

597oF Vapor

I

CS CS OverFlash 650-700

  • F

9Cr 5Cr 600-650

  • F

Quench Flash Zone 750oF 750-760

  • F

316L SS

I

Feed Surge Drum (5Cr) 625-650

  • F

5Cr 5Cr Atmos. Resid 9Cr 5Cr CS 316L SS 5Cr 9Cr F-1 Charge Heater Fuel Gas/Distillate to Vacuum System 275oF CS U26.1 U25.1 5Cr U25.1 CP CP CP 5Cr CP CP CP

CP CP

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Benchmarking Nalco Scorpion Applications

1 2 3 4 5 6 7 8

1% of Applications > 6 3% of Applications > 4 22% of Applications > 3 33% of Applications > 2 59% of Applications > 1 85% of Applications > 0.5

How Does SCORPION Work?

Inhibitors work by forming an extremely tenacious

and persistent passive surface

Currently there are three types of SCORPION

inhibitors supplied by Nalco

  • Phosphorous-based
  • Sulphur-based
  • Phosphorous and Sulphur based

Nalco possessed patents on Phosphate ester

chemistry, and possesses patents on Sulphur and combination chemistries.

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How Long Does the Film Persist?

 Example shown: >14 days  A lot less for a transfer line  Depends on velocity and turbulence

C o r r o s i o n R a t e a n d % H A C C r u d e

1 2 3 4 5 6 7 8 9 1 0

3

  • M

a r 8

  • M

a r 1 3

  • M

a r 1 8

  • M

a r 2 3

  • M

a r 2 8

  • M

a r 2

  • A

p r 7

  • A

p r 1 2

  • A

p r 1 7

  • A

p r 2 2

  • A

p r 2 7

  • A

p r 2

  • M

a y 7

  • M

a y 1 2

  • M

a y 1 7

  • M

a y 2 2

  • M

a y 2 7

  • M

a y 1

  • J

u n 6

  • J

u n 1 1

  • J

u n 1 6

  • J

u n 2 1

  • J

u n 2 6

  • J

u n 1

  • J

u l 6

  • J

u l 1 1

  • J

u l 1 6

  • J

u l D a t e

Corrosion Rate (mpy)

1 0 2 0 3 0 4 0 5 0 6 0

% HAC Crude / Inhibitor (ppm)

C o r r o s i o n R a t e I n h i b i t o r ( E C 1 2 4 5 A ) % H A C C r u d e

Impact of Inhibitor

U n tre a te d T r e a te d U n tre a te d T r e a te d 4 1 0 S S 9 Chrom e 5 Chrom e C a r b o n S te e l

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Corrosivity (mm/yr)

D O B A C o rro sivity T estin g

4 1 0 S S 9 C h ro m e 5 C h ro m e C a rb o n S te e l LVG O C U T 370-425 C H VG O C U T 510-555 C

Inhibitor Comparative Performance w/Various Crudes

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Naphthenic Acids other impacts

Impact on Tank Farm

  • Poor water removal
  • Emulsion formation in

tankage

Impact on Desalter

  • Emulsion in desalter
  • Oil undercarry
  • Water carryover

Tank Farm Solutions

  • Tank mixers
  • Crude blending
  • Tankage dehydration

additives

Desalter Solutions

  • Increase wash water
  • Increase temperature
  • Increase mixing
  • Demulsifier selection

Summary

 Processing opportunity crudes (e.g. High TAN) can

significantly improve refinery profitability, often offer >US$10/bbl discounts

 Testing can be done before the crude arrives to identify

potential risks in desalting, fouling, corrosion, and waste plant

 Communication between buyers, refiners and crude

process aid suppliers is key to successful introduction

 Planning ahead can allow the refiner to reduce unknown

risks associated with running Challenge/Opportunity Crudes

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SCORPION High Temperature Corrosion Control Protecting Your Plant and Profits

Crude Challenge – Low TAN, High Sulfur SCORPION High Temperature Corrosion Control

  • Proven effective against Sulfidic attack in the lab
  • Proven effective against Sulfidic attack in the field 2008 - present

EuroCorr 2007 paper, Hydrocarbon Engineering article, September 2008;

  • Chemical Inhibition of High Temperature Sulphidic Corrosion in Lab Evaluations

and Petroleum Refinery Applications, C. Claesen, S. A. Lordo, G. Scattergood

2008 paper, March 2009 article in Hydrocarbon Engineering

  • Chemical Inhibition of Sulfidic Corrosion at Chinese Refinery, V. Chua, G.

Scattergood

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Thank you