non standard tests for predict impact of crude oil quality on

Copyright 2003 Baker Hughes Incorporated

Non Standard Tests for Predict Impact of Crude Oil Quality

on Desalting.

Larry Kremer, Baker PetroliteCrude Oil Quality Group

May 29, 2003

This presentation contains the proprietary information of Baker Petrolite Corporation. By reading this presentation, the reader agrees not to disclose any information contained in the presentation without the prior written consent of Baker Petrolite Corporation, and that the use of the information contained in this presentation is subject to the provisions contained in the Legal Notice included with this Slide Program.


Outline

� Introduction� Electrostatic Desalter Demulsification

Apparatus (EDDA)� Filterable solids� Asphaltene Stability Index Test (ASIT)


Problem with Standard Tests

� Full crude assay� Gravity, %S, %N, SARA, etc.� Does not predict how crude will perform in a

desalter.� Daily variation

� BS&W� Salt in crude

� Refineries normally run blends of crudes


Electrostatic Desalter Demulsification Apparatus


Canadian Crude Refinery(3, 5, 7, 9% wash water)

Water Drop Rate for Different %Wash Water in Crude#1

0

1

2

3

4

5

6

7

8

9

0 5 10 15 20 25 30 35

Electrostatic Demulsification Dehydration Time (min.)

% w

ater

dro

p


Filterable Solids

� Can be measured by ASTM D 4807-88� Washed with toluene to solubilize

asphaltenes� Filtered through 0.45mm filter

� Solids are known to stabilize emulsions� Logan C Waterman -1965� Wasan� Masliyah


Filterable Solids of Selected Crude Oils

CRUDE OIL TYPICAL RANGE HIGH VALUE

Lloydminster 50-150PTB 280

SJV 50-200 800

ANS 25-50 115


Typical Solids Analysis

� Iron Oxide and Iron Sulfide� Sand� Clay� Silt� Scale


Solids Stabilized Emulsion5% Wash Water Added

100 X


Solids and Surfactant MoleculesStabilizing The Oil - Water Interface

EmulsifiedEmulsifiedWaterWater

DropletDroplet

Emulsion Emulsion -- StabilizingStabilizingSolidsSolids

OILOILEmulsion Emulsion --

Stabilizing MoleculesStabilizing Molecules


PTB


Asphaltene Stabilized Emulsions

� Asphaltenes exist as a cross linked network at the oil-water interface� Asphaltene networks form strong interfacial

films stabilizing the emulsion� Asphaltenes at their limit of solubility in

the oil form the most stable emulsions� Predicting asphaltene stability may help

improve desalting operations


Stability Indicators

� Asphaltene to Resin ratio, Saturate to Aromatic ratio� A/R ratio > 0.35 indicates oil has propensity to

asphaltene destabilization� Generally, do not mix high S/A oil with low S/A oil

� Spot tests� Single solvent spot tests, mixed solvent spot tests,

microscope investigations� ASITSM asphaltene stability index test


0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

0.00 0.50 1.00 1.50 2.00 2.50 3.00

Crude #1Crude #2Crude #3Crude #4Crude #4 + Additive

Additives can greatlyincrease the stability

of an oil

ASITSM

Asphaltene Stability Index TestIn

tens

ity

ASI


ASITSM

Asphaltene Stability Index Test

� Used to determine stability of crude oil with regard to asphaltene stability

� Uses NIR laser to detect asphaltene precipitation in petroleum fluids

� Titration technique with non-solvent� Stability based on field correlated results� Gives qualitative information on rate of

fouling


Case History 3

� Introduction of Crude 9 at 50% of normal crude feed resulting in formation of an unusual rag layer & level control problems in preflash tower� Foaming was determined to be the cause of

the level control problems of preflash tower� Blending Crude 9 with other crude oils

resulted in poor desalting and an increase in BS&W


# Oil / Blend ASI 9 Crude 9 1.36

10 Crude 10 1.89 13 80% (Crude 9) 20% (Crude 10) 1.38 14 60% (Crude 9) 40% (Crude 10) 1.48 15 40% (Crude 9) 60% (Crude 10) 1.62 16 20% (Crude 9) 80% (Crude 10) 1.72

C a s e 3A S IT S M A s p h a lte n e S ta b ility In d e x T e s t

05 0

1 0 01 5 02 0 02 5 03 0 03 5 04 0 0

0 0 .5 1 1 .5 2 2 .5A S I

Inte

nsity

# 9

# 1 0

# 1 3

# 1 4

# 1 5

# 1 6


# Oil / Blend ASI 9 Crude 9 1.36

11 Crude 11 1.03 17 84%(Crude 9) 16% (Crude 11) 1.09

Case 3 ASITSM Asphaltene Stability Index Test

0

100

200

300

400

500

600

0 0.5 1 1.5 2ASI

Inte

nsity

# 9# 11# 17# 17 & Additive


EDDA Demulsification Test

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

# 17 # 17 & AsphalteneStaiblizer

# 17, Stabilizer &Demulsifier

Total Wash Water Added = 5%

% W

ater

Dro

p

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

BS&

W %

Water Drop 5 minWater Drop 10 minBS&W


Outcome of Case History 3

� Crude 9 was reduced to 40% or less of the normal feed

� Additives containing asphaltene stabilizers were added to Crude 9 as it was transferred to tank storage

� Addition of asphaltene stabilizer allows refinery to run 85% crude 9 without problems

� Demulsifier program was changed� Asphaltenes destabilization believed to be

contributing cause of foaming in preflash tower� Defoamer injected into feed of preflash tower


Conclusions

� ASITSM asphaltene stability index test, Filterable Solids & Electrostatic desalter dehydration apparatus (EDDA) testing are predictive tools for desalting operations� Used to optimize blending strategies &

indicate problematic blends� Sensitive to small changes in blend

components� Filterable solids are useful in monitoring

batch to batch variation in crude quality.

non standard tests for predict impact of crude oil quality on

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