LHN Meter Proving 25241-01

Lesson Handout Notes

25241 METER PROVING

A69.1858-LHN-PRO-25241-01

Effective Date: September 11th , 2007

Training Program : TECHNICIAN: LEVEL 2 CERTIFICATION

Discipline : PROCESS

System : METERING & GAUGING

Sub-System : METER PROVING

Training Focus : PRACTICAL KNOWLEDGE

Training Elements : This lesson targets training on the following training elements: Meter Proving

Meter Proving Systems

Training Objectives : At the end of the Lesson the participants will be able to: Describe how a meter proving system works Extract relevant information from a meter proving run

0 2007-09-11 V. Vladut VV T. Hedison TJH R.G. Hollamby RGH Initial Document

Rev Date Prepared by Initials Checked by Initials Approved by Initials Modifications

Form: A62.1858-ADM-FRM-0303 Cegelec 2006 of 9

This document is the property of Cegelec (The Company). Distribution and use of this document are strictly governed by the Company’s Document Management Policy and Procedures. The contents and form of the document are the sole property of The Company and may not be reproduced, distributed or used without the express written permission of The Company.

Lesson Handout Notes 25241: Meter Proving

A62.1858-LHN-PRO-25241-01

September 11th 2007

25231: Meter Proving Cegelec 2007 of 9

DOCUMENT INFORMATION

TABLE OF CONTENTS

Technician: Level 2 Certification ................................................................................................................................... 1 Process ......................................................................................................................................................................... 1 Metering & Gauging ...................................................................................................................................................... 1 METER PROVING ........................................................................................................................................................ 1 Practical Knowledge ..................................................................................................................................................... 1 Metering definitions ....................................................................................................................................................... 3 Proving system ............................................................................................................................................................. 3 Pipe prover ................................................................................................................................................................... 4 Types of prover pipes ................................................................................................................................................... 5 Bidirectional pipe prover ............................................................................................................................................... 6 Metering Facilities……………...………………………………………………………………………………………………..7

Purpose The purpose of this document is to provide the participant study information. OWNER The owner of this document is the Discipline Team of Ogere Training Facility, Ogere Remo, Ogun State, Nigeria. CUSTODIAN The custodian of this document is the Data Administrator and Document Controller of the Ogere Training Facility, Nigeria


A62.1858-LHN-PRO-25241-01

September 11th 2007


Metering definitions

Custody and fiscal transfer involve royalties; so the main characteristic of a metering system is to reduce inaccuracies to a minimum. For flow, accuracy depends on the type of measurement

- Operational measurement: # 5 %

- Control measurement: # 2 %

- Custody and fiscal transfer: < 1 % for gases and < 0.5 % for liquids

Example: For 1 million of barrels of oil per day the calculation is based on $50 per barrel.

A 0.1 % error represents $50 000 per day.

Design, installation, maintenance and operation of a station should be covered by standards agreed by the Buyer and the Seller and based upon:

- governmental requirements

- industry practices

- company guidelines

The station shall be certified by a third party certifying agency. Custody transfer involves export metering and fiscal transfer involves domestic metering.

Proving system

Proving system is necessary for the accurate determination of the meter calibration factor MF

(number of pulses per unit volume). Proving shall be in accordance with ISO or API standards.

Different systems:

1. Master meter

- uses an accurate meter in series with the meter to be calibrated;

2. Volumetric prover

- uses a vessel of an accurate certified volume;

- considerable time is required for filling, draining and return of the test fluid;

- normal operation of the meter must be interrupted.

3. Prover pipe

- uses of an accurate certified volume of pipe;

- time is relatively short.

- normal operation of the meter will not be interrupted.


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The Prover pipe Consist mainly of: - A pipe section with an exact determined volume limited by two detectors; - A sphere or a piston (neoprene); - A high resolution prover counter; The sphere or piston actuates the two detectors which in turn will start and stop the counting of electrical pulses.

Figure 1. Typical prover pipe

The prover counter determines:

• P and T corrected prover volume Vp from original volume Vo (established by a

certifying authority)

Vp = Vo x Cts x Cps x Ctl x Cpl

Where:

Cts: correction factor for effect of temp. on prover material (API 2531 table I)

Cps: correction factor for effect of pres. on prover material (API 2531 table II)

Ctl: correction factor for effect of temp. on liquid (ASTM D1250 table VI)

Cpl: correction factor for effect of pres. on liquid (API 1101 table II)

• Actual meter calibration factor

MF1 = n1/Vp

Where n1 = number of pulses.


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Types of prover pipe

- Unidirectional:

The sphere passes through the section always in the same direction and is returned to the upstream end through an interchange.

- Bidirectional:

The sphere passes through the section back and forth. The change of direction is accomplished by means of a 4-way-diverter-valve or a combination of valves. Prover can be stationary or mobile depending on the size of the station.

Requirements:

For every loading the meter has to be proved and shall require participation of both Parties.

Periodic testing shall be as often as weekly.

Proving should start after flow parameters (P, T, μ, and F) are stabilized.

To obtain accuracy and repeatability <= 0.02 %:

- Vp shall be at least 0.5 % of the maximum volume per hour;

- A minimum of 10 000 pulses has to be generated;

- The sphere velocity shall not exceed 3 m/s;

- Possible change in the volume shall never exceed 0.1 %;

- Usually if 3 to 5 successive runs agree within 0.02 % of each other, MF is considered

accurate;

- Assure that there is no leakage around the sphere in its passage;

- A test shall be carried-out if there are large variations of pressure, temperature, viscosity and

flow during normal operation.

Prover loop calibration system

It is used to calibrate prover loop volume at periodically period and to determine official prover loop volume. It consists of several calibrated tanks and transfer pump connected to prover loop.


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Figure 2. Bidirectional pipe prover


A62.1858-LHN-PRO-25241-01

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Metering Facilities

This example of a metering system for cargo products and bunkering products consists of ten metering banks. The metering banks accurately measure the volume of products delivered to tankers. The banks also control and monitor the flow of products as they are delivered.

The following products are transferred from the refinery through dedicated pipelines to tankers, passing the metering system:

FOC : Fuel Oil Cargo

FOB : Fuel Oil Bunker

PG : Premium Gasoline

RG : Regular Gasoline

MDB : Marine Diesel Bunker

MDC : Marine Diesel Cargo

MDO : Motor Diesel Oil

KE : Kerosene

NA : Naphtha

JP - 4 : Jet Fuel

LPG : Liquefied Petroleum Gas

The number of meter runs to be used for each loading is based on a maximum required flow rate. For each metering bank, a unidirectional prover loop verifies the accuracy of the meters. This occurs while loading operation is at normal flow rate. The metering and pipe prover functions are operated from the control room at the terminal administration building. Manual proving can also be done at the metering stations.


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Figure 3. Product flow through a meter proving system for the FOC and FOB Skids

Figure 4. Typical configuration of a metering skid.


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The product metering systems have a common inlet header and multiple meters. These are dedicated to loading berths as follows:

Product

Meters to Berth 1 & 2

Meters to Berth 3 & 4

Meter Type

Number Size Number Size

Fuel Oil Cargo (FOC) 4 12” 4 12” PDM

Regular Gasoline (RG) 3 10” 3 10” TM

Premium Gasoline (PG) 3 10” 3 10” TM

Marine Diesel Cargo (MDC)

3 10” 3 10” TM

Motor Diesel Oil (MDO) 3 10” 3 10” TM

Kerosene (KE) 3 10” 3 8” TM

Naphtha (NA) 2 6” 2 6” TM

Jet Fuel (JP-4) 2 4” 2 4” TM

Fuel Oil Bunker (FOB) 3 8” 3 8” PDM

Marine Diesel Bunker (MDB)

2 6” 2 4” TM

LHN Meter Proving 25241-01

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