Static Liquid Measurement Standards Tank Gauging (Ch 3) Christian Skaug, Emerson

Large storage tanks (65+ ft high, 160+ ft diameter) Think about Oil price @ ~100 USD / bbl Each mm is a lot of inventory value $$$$

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API standards MPMS Ch. 2 Tank Calibration MPMS Ch. 3.1A Manual Gauging MPMS Ch. 3.1B Automatic Tank Gauging (Atmospheric) MPMS Ch. 3.3 Automatic Tank Gauging (Pressurized) MPMS Ch. 3.4 Automatic Tank Gauging (Marine, Atmospheric) MPMS Ch. 3.5 Automatic Tank Gauging (Marine, Pressurized) MPMS Ch. 3.6 Hybrid Measurements MPMS Ch. 7 Temperature Measurements MPMS Ch. 7.3 Automatic Tank Temperature Measurements MPMS Ch. 11 Physical Properties Data (VCFs) MPMS Ch. 12 Calculations API 2350 Overfill Protection

Ch. 8 (Sampl.) Ch. 9

(Density)

Ch. 3.1A

ATT ATG

PT

PT

Ch. 7 Ch. 3.1B

Ch. 3.6 (Online Density)

Ch. 11 (VCF) Ch. 12

(Calc.) Ch. 2 (Tank Cal.)

Ch. 3.3 (Level)

Ch. 7.3 (Temp)

The API standards typically covers:

Equipment requirements Design Performance

Installation guidelines for best measurement result in the field for

different applications (best practice, considerations)

Procedures

Physical Properties Data and Calculations

Best practices in tank gauging

MPMS Ch. 3.1A (Manual Gauging):

- Land and marine tanks

- Health and safety precautions

- Equipment

- Gauging procedures

- Accuracy and Traceability

MPMS Ch. 3.1A, verification of working tapes:

- Calibrated master tape - Regular intervals - Within +/-2 mm

MPMS Ch. 3.1B & 3.3, installation and procedures (example):

Typical guidance include: - Stability, still pipe requirements etc - Considerations such as turbulence - Calibration/Verification procedures

MPMS Ch. 3.1B, CT accuracy requirements

Requirement Custody transfer

Factory calibration 1 mm (1/16 in) Effect of installation 3 mm (1/8 in) Initial verification 4 mm (3/16 in) Subsequent verification

4 mm (3/16 in)

Example (verification of ATG)

Tank Movement

Good procedures are very important!

Date Time Ullage Dip 1 Ullage Dip 2 Ullage Dip 3 Avg. Ullage Level Gauge Diff. Level Remark/ Tape id Sign

Dip Reading Gauge - Dip

mm mm mm mm Ullage mm mm

200x-xx-xx 10.20 16144 16144 16144 16144 16144 0 TT-CS tape (calibrated) TT-CS

200x-xx-xx 10.30 16149 16149 16144 -5 Tape No. 1 (bad) Person 1200x-xx-xx 10.35 16142 16142 16142 16144 2 Tape No. 2 (OK?) Person 1

200x-xx-xx 10.40 16143 16143 16144 1 TT-CS tape (calibrated) Person 1

200x-xx-xx 11.00 16699 16701 16704 16701 16694 -7

16713 after (tank was emptying despite information that level should be stable, would'nt be discovered if only one handdip was taken.) TT-CS

200x-xx-xx 16.00 16838 16837 16838 16838 16839 1 TT-CS

Bad tape Different person

MPMS Ch. 3.6, Hybrid Tank Measurement System: - Four major components

- ATG - ATT - Pressure sensors - Hybrid processor

- Density or Mass

- Uncertainty calculations

MPMS Ch. 3.6, Hybrid Tank Measurement System:

CT Accuracy Requirements @ 4 m level: Requirement Custody transfer Density 0.5%

MPMS Ch. 7.x overview Current Ch 7 will be split up in the following chapters: Ch. 7.1: Liquid-In-Glass Thermometers (pending) Ch. 7.2: PETs (pending) Ch. 7.3: Fixed Automatic Tank Temperature Systems (Oct 2011) Ch. 7.4: Dynamic Temperature Measurement (pending)

MPMS Ch. 7.3, Equipment requirements (example):

Maximum filling height

Sensor 1

Sensor 2

Sensor n

Sensor n+1

Sensor 3

Anchor weight

Flexible element housing (probe)

Junction box or temperature transmitter

-Temperature sensors -Stratification -...

MPMS Ch. 7.3, CT system accuracy requirements:

Requirement Custody transfer Factory calibration 0.25 C (0.5 F) Initial Field Verification 0.25 C (0.5 F) Subsequent Verification

0.5 C (1 F)

MPMS Ch. 11 (Reference Density Calculations)

Different tables for different product types (53A, 53B,)

Input: Observed Density Average Temperature Etc

Output:

Reference Density

MPMS Ch. 11 (VFC Calculations)

Different tables for different product types (54A, 54B,)

Input: Reference Density Average Temperature Etc

Output:

VCF

MPMS Ch. 12.1.1 (Calculations Static Petroleum Quantities)

Ch. 8 (Sampl.) Ch. 9

(Density)

Ch. 3.1A

ATT ATG

PT

PT

Ch. 7 Ch. 3.1B

Ch. 3.6 (Online Density)

Ch. 11 (VCF) Ch. 12

(Calc.) Ch. 2 (Tank Cal.)

Ch. 3.3 (Level)

Ch. 7.3 (Temp)

Tank gauging coverage

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Temp

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Equip

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Certif

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Lega

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Labo

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envir

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Field

Envir

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Instal

lation

guide

lines

Proce

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Tank

Calib

ration

Hybri

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surem

ent

Physi

cal Pr

opert

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Calcu

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Custo

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ansfe

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Inven

tory

API

OIML

ISO

Other

API standards usage:

Customers want guidelines they know will be accepted world wide (buying/selling). Much easier if possible to say in compliance with API requirements.

Some customers more or less adopt the standards as their own and make them mandatory requirements.

Easy to use already written procedures at situations like FAT, SAT (inspections etc)

Up to date standards

Aim to harmonize requirements with standards in other standardization organizations => wider acceptance

THANK YOU!

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