Firefighting Tank Verification

Verification & Recommendation Report

PREPARED BY:
OFFSHORE DESIGN ENGINEERING

FOR:

Client Company Name:

EL WASTANI PETROLEUM COMPANY
Document Number: 358051-PRO-RP-40000
Rev.A
Issue Date: 22 November 2017
Firefighting Tank Verification
Verification & Recommendation Report

DISCLAIMER

All information contained within this document must only be used for the purpose under that for which it
was contracted. As such the information should not be used as a basis for any fabrication, construction,
installation and/or operation other than as already agreed in writing by ODE without further engineering
studies to validate its application. ODE cannot be held liable for the consequences of any use or misuse of
the information contained within this report which exceeds its original and stated purpose.

APPROVAL

Author: Checked: Approved:

Name: Name: Name:
Yahya Abdelbarr Ahmad Eshra Dina Kabesh
Job Title: Job Title: Job Title:
Process Engineer Lead Process Engineer Project Manager
Signature: Signature: Signature:

Date: 22/11/2017 Date: 22/11/2017 Date: 22/11/2017

A 22/11/2017 Issued for CRC YA AIE DK

Issued Checked Approved
Rev No Date Status
By By By

REVISION RECORD SHEET

Revision
Purpose List of Updated/Modified Sections
Number
A Issued for CRC First Issue

HOLDS

Revision
Description of HOLD Section
Number
- None -

358051-PRO-RP-40000 Rev.A Page 2 November 2017

Firefighting Tank Verification
Verification & Recommendation Report

CONTENTS
1. INTRODUCTION ................................................................................................................. 4
2. TANK VOLUME VERIFICATION......................................................................................... 5
3. NOZZLES VERIFICATION .................................................................................................. 6
3.1 Tank T-7301 Nozzles ............................................................................................. 6
4. TANK TYPE VERIFICATION .............................................................................................. 7
4.1 Blanketing Gas ....................................................................................................... 7
5. ACCESSORIES & INSTRUMENTATION ............................................................................ 8
5.1 PVRV & Flame Arrestor ......................................................................................... 8
5.2 Temperature Indicator ............................................................................................ 8
5.3 Level Transmitters.................................................................................................. 8
6. FIREFIGHTING ................................................................................................................... 9
7. CONCLUSION................................................................................................................... 10
8. REFERENCES .................................................................................................................. 11

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Firefighting Tank Verification
Verification & Recommendation Report

1. INTRODUCTION
WASCO has an existing firefighting tank with a total capacity of 1,514 m3 located at
El-Wastani Plant. The proposed extension of the firewater system will require a new
larger capacity tank. Therefore, WASCO wish to investigate the possibility of reusing
the current firewater tank and an additional condensate storage tank.

The current operating philosophy is using 2 condensate storage tanks 15,000 Bbls/
EA. One for filling mode and the second for dispatching. The proposed scenario is to
tie-in the modified firewater tank to be operated in parallel with the two existing
condensate tanks.

Figure 1 WASCO Firewater Tank

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Firefighting Tank Verification
Verification & Recommendation Report

2. TANK VOLUME VERIFICATION

Firewater tank T-7301 is to be assessed in terms of operating capacity in order to
calculate the maximum throughput the tank can handle. The tank data received from
WASCO is as follows:

Parameter Unit Value

Diameter m 13.41

Height m 10.97

Capacity m3 1,514.2

Max Operating Capacity m3 1,362.8

Design Pressure ATM 1

Design Temperature C AMB

Table 1 Firewater Tank T-7301 Data

According to the data provided by WASCO, the total flowrate for the stabilized
condensate from both the existing CPF and the new standalone processing facility (SPF)
is 7,972 Bbls/d. Assuming the case of filling Tank T-7301 solely, the required filling time
is 26 hours.

Downstream the condensate storage tanks, five pumps are installed; two boosting pumps
and the other three ones are for transferring purposes. They all have the same actual
capacity which is 572 USGPM. Accordingly, the required time to empty Tank T-7301
completely is 10.5 hours.

Parameter Unit Value

Filling Time Hr 26

Dispatching Time Hr 10.5

Table 2 Tank T-7301 Findings

358051-PRO-RP-40000 Rev.A Page 5 November 2017

Firefighting Tank Verification
Verification & Recommendation Report

3. NOZZLES VERIFICATION

3.1 Tank T-7301 Nozzles

Figure 2 Firewater Tank T-7301 Nozzles

As shown in the figure above, the mechanical drawing for Firewater Tank T-7301 and the
existing nozzles are not enough for the required service of stabilized condensate storing.
Additional nozzles must be constructed to make the tank fit for its designated future
service.

Level transmitting instruments must be installed on the tank to ensure a proper operation.
Furthermore, a nozzle for PVRV is to be constructed to prevent the tank from pressure
fluctuations. To monitor the temperature inside the tank, a temperature indicator is to be
installed on the tank.

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Firefighting Tank Verification
Verification & Recommendation Report

4. TANK TYPE VERIFICATION

Floating roof tanks are the most proper type of tanks to be used for stabilized condensate
storing, as they provide safe, efficient storage of volatile products with minimum vapor
loss to the environment. However, the firewater tank is of fixed roof type and to make fit
to store stabilized condensate installing blanketing system is a must either by gas or by
nitrogen.

As the two existing storage tanks are of the same type of the assessed one, it is
expected to find a gas blanketing system existing on site to ensure safe operation of the
existing ones. This system could be utilised to the proposed fire water tank.

4.1 Blanketing Gas

Fuel gas is to be used as blanketing gas for the assessed tank. As per WASCO
documents the fuel gas composition is as follows:

Component Mole%

H2O 0.00

CO2 0.32

Nitrogen 0.14

Methane 92.23

Ethane 5.77

Propane 1.29

i-Butane 0.16

n-Butane 0.08
Table 3 Blanketing Gas Composition

The blanketing gas flowrate calculations were made based on API 2000. The calculated
flowrate is the summation of the required gas flow due to pump-out and secondly the gas
flow rate due to atmospheric thermal cooling.

The required gas flow due to maximum pump-out rate is 4,590 SCFH, and the required
gas flow due to atmospheric thermal cooling is 15,000 SCFH, which in turn gives a total
gas flowrate of 19,590 SCFH.

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Firefighting Tank Verification
Verification & Recommendation Report

5. ACCESSORIES & INSTRUMENTATION

The current tank instruments and accessories are not enough to operate the tank
efficiently and in a safe mode. Proper sets of instruments and accessories are needed
and they can be summarized as follows:

5.1 PVRV & Flame Arrestor

A pressure vacuum relief valve along with a flame arrestor needs to be installed on the
tank in order to accommodate the pressure fluctuations inside the tank.

5.2 Temperature Indicator

A temperature indicator is to be installed on the tank in order to monitor the temperature

which is a very important factor in properly storing the stabilized condensate.

5.3 Level Transmitters

Level transmitters are needed to be installed to the tank in order to monitor the
condensate level inside the tank, and even send signals to controllers when upsets take
place.

A HLL & LLL transmitter is to be installed along with two other sets of level transmitters;
the first set for monitoring the HHLL and the second one for monitoring the LLLL.

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Firefighting Tank Verification
Verification & Recommendation Report

6. FIREFIGHTING
The current tank has no firefighting accessories which is not acceptable with its new
proposed designated service. Cooling rings with water spray nozzles along with all
accessories and equipment shall be installed on the tank. Additionally, foam system is to
be installed also on the tank.

Hydrants and monitors are to be installed near the tank.

Accessories and equipment to be installed according to the codes and standards of

firefighting i.e. NFPA.

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Firefighting Tank Verification
Verification & Recommendation Report

7. CONCLUSION
In terms of capacity, the firewater tank T-7301 is smaller than the current two tanks used
to store the stabilized condensate, however its size wont cause any disruption to the
current process as it will give more condensate storing capacity to the system anyways.

In terms of tank type, storing stabilized condensate is recommended in floating roof tanks
whilst the existing firewater tank is of fixed roof type and in order to make fit for service
gas blanketing is to be applied to the tank.

In terms of the available nozzles, there are not enough in order to properly operate the
tanks for its new designated service. New nozzles must be drilled in the tank in order to
install the required instruments and accessories.

On the safety side, firefighting systems and equipment must be installed on the firewater
tank according to the prevailing codes and standards.

Finally, visual inspection and change in service tests have taken place in order to assess
the integrity of the tank, and there were no any raised concerns as per OCA Egypt
External Visual Tank Inspection Report No.: 0015/0020/2320/0020/001 and OCA Egypt
Change in Service Assessment Report No.: 0115/0020/2320/0020/002.

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Firefighting Tank Verification
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8. REFERENCES
OCA Egypt Change in Service Assessment Report No.:
0115/0020/2320/0020/002

OCA Egypt External Visual Tank Inspection Report No.:

0015/0020/2320/0020/001

358051-PRO-RP-40000 Rev.A Page 11 November 2017

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Telephone: +20 2 2517 2631

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