PROCESS ENGINEERING
No. Dokumen
DISPERSION STUDY
FMLP-LNG-GTL-PRO-CALC-005
Revisi
Halaman
B
1 dari 10
PEMBERI KERJA
:
PT. LIKUID NUSANTARA GAS
KONTRAKTOR
:
PT GT LADANG TEKNIK
NAMA PROYEK
:
FEED FOR MINI LNG PLANT
LOKASI
:
Pasuruan Industrial Estate Rembang
NO. KONTRAK
:
LNG-01-SPK-240123-YFT00
B
17 Jul 2023
Issued for Approval
RB
FNS
UT
A
21 Jun 2023
Issued for Review
RB
FNS
UT
Prepare
Review
Approve
REV
TANGGAL
STATUS
PT GT LADANG TEKNIK
Review
Approve
PT. LIKUID
NUSANTARA GAS
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DISPERSION STUDY
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LEMBAR REVISI
REV
TANGGAL
HAL.
KETERANGAN
A
21 June 2023
All
Issued For Review
B
17 July 2023
All
Issued For Approval
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DISPERSION STUDY
FMLP-LNG-GTL-PRO-CALC-005
DAFTAR ISI
1.
GENERAL ........................................................................................................................... 4
2.
OBJECTIVE ........................................................................................................................ 4
3.
DEFINITION AND ABBREFIATION .................................................................................... 4
3.1
Definition ................................................................................................................... 4
3.2
Abbreviation.............................................................................................................. 5
4.
REFERENCES, DOCUMENTS, CODES AND STANDARDS ............................................. 5
5.
GENERAL DESIGN CONDITION AND CRITERIA.............................................................. 5
6.
7.
5.1
Environmental Data .................................................................................................. 5
5.2
Fluid Composition .................................................................................................... 5
5.3
Fluid Data .................................................................................................................. 6
5.4
Vent Data ................................................................................................................... 6
CALCULATION METHOD................................................................................................... 6
6.1
Vent Load .................................................................................................................. 6
6.2
Dispersion Study ...................................................................................................... 6
RESULT .............................................................................................................................. 7
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DISPERSION STUDY
FMLP-LNG-GTL-PRO-CALC-005
1.
GENERAL
PT. Likuid Nusantara Gas (PT LNG) plan to build Mini LNG Plant. The Plant capacity is 2.5
MMSCFD. The Plant is design to process natural gas by separating the impurities and liquify
it into LNG. The plant also have 40 ft Isotank filling station and also have VGL filling station.
The plant located in Pasuruan Industrial Estate Rembang, East Java. The plant location is
stated in picture below.
Picture 1.1 Mini LNG Plant Location
2.
OBJECTIVE
This document is developed to describe dispersion of gas during venting operation for Mini
LNG Plant Pasuruan owned by PT Likuid Nusantara Gas.
3.
DEFINITION AND ABBREFIATION
3.1
Definition
PT LNG
: PT Likuid Nusantara Gas, as Project Owner
PROYEK
: Mini LNG Plant Pasuruan
CONSULTANT
: PT GT Ladang Teknik
MIGAS
: Badan pemerintah Indonesia yang bertanggung jawab
dalam hal menerbitkan ijin operasi dan pengelolaan untuk
fasilitas Minyak dan Gas.
PT PGS
: PT Penta Gas Solusi, Technology Provider that supply Mini
LNG Plant main process.
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Certification Agency
3.2
4.
: Third Party Inspection Agency as MIGAS representative.
Abbreviation
P&ID
: Piping & Instrument Diagram
NPSH
: Process Control Systems
LLL
: Low Low Level
HHLL
: High High Level
REFERENCES, DOCUMENTS, CODES AND STANDARDS
Code and Standard that use in this calculation are:

API STD 520
Sizing, Selection, and Installation
of Pressure- Relieving
Devices in Refineries

API STD 521
Pressure-Relieving and Depressurizing Systems
5.
GENERAL DESIGN CONDITION AND CRITERIA
5.1
Environmental Data
The environment data for West Batara Facility are as follow:
5.2

Temperature
: 35oC

Relative Humidity
: 85% (average)

Wind Speed
: 5 m/s. 2.5 m/s, dan 1.5 m/s (estimated)
Fluid Composition
Fluid composition used are describe as follow:
Table 4. Fluid Specification
ITEM
Nitrogen
Carbon Dioxide
Methane
Ethane
Propane
I-Butane
N-Butane
I-Pentane
N-Pentane
Hexane +
UNIT
% Mole
% Mole
% Mole
% Mole
% Mole
% Mole
% Mole
% Mole
% Mole
% Mole
VALUE
0.024
0.930
97.531
0.723
0.433
0.118
0.128
0.050
0.039
0.024
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5.3
Fluid Data
Fluid data for vent dispersion study is taken from the worst case of PSV outlet rate at pipeline
area.
FLUID DATA
Gas Flow Rate
Pressure
Temperature
5.4
UNIT
kg/hr
MMSCFD
Barg
o
C
VALUE
6566
7.893
1.38
35
Vent Data
Vent data that will be used for simulation are:
6.
6.1
 Type of Vent
: Vent Stack
 Vent Height
: 10 meter
 Dimension
: 6 inch
 Angle Discharge
: 90 degree
CALCULATION METHOD
Vent Load
The source of disposed gas is coming from PSV at pipeline area. Load of this PSV shall
be the basis of designing Vent Stack.
6.2
Dispersion Study
The Analysis of vent stack dispersion is performed by DNV PHAST 8.4 simulation software.
This software shall simulate gas dispersion that will occur when venting operation is
conducted. Simulation will be conduct base on passcuil F (night condition) and pascuil D (day
condition).
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DISPERSION STUDY
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7.
RESULT
Result of Cloud Dispersion Side View Graphic Analysis is summarize in table below. This
calculation use the longest section as the basis.
Table 1. Cloud Dispersion Side View Graphic Analysis
Case
Day
Night
Day
Night
Day
Night
Day
Night
Wind
Speed
1.5 m/s
2.5 m/s
5 m/s
10 m/s
a. Wind Velocity 1.5 m/s

Day
Cloud distance for concentration
Cloud Elevation
(HFL)
(LFL)
(50% LFL)
0.41 m
1.8 m
3.94 m
10-28.14 m
0.50 m
1.81 m
3.59 m
10-27.20 m
0.50 m
1.91 m
4.13 m
10-24.42 m
0.53 m
1.84 m
3.76 m
10-23.55 m
0.40 m
2.04 m
4.36 m
10-19.97 m
0.42 m
1.91 m
3.95 m
10-19.41 m
0.53 m
2.1 m
4.70 m
10-16.75 m
0.55 m
1.98 m
4.30 m
10-16.4 m
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
Night
b. Wind Velocity 2.5 m/s

Day

Night
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c. Wind Velocity 5 m/s

Day

Night
d. Wind Velocity 10 m/s

Day
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
Night