Calculation and Specification of Compressed Air System: Design Iv Machinery System Department of Marine Engineering
Calculation and Specification of Compressed Air System: Design Iv Machinery System Department of Marine Engineering
Calculation and Specification of Compressed Air System: Design Iv Machinery System Department of Marine Engineering
Prepared by Approved by
Rev. Date Remark A.A.B. Dinariyana D. P., S.T.,
Sean Chen Gyarino
MES., Ph.D.
DESIGN IV MACHINERY SYSTEM
DEPARTMENT OF MARINE ENGINEERING
ATTACHMENT
I. INTRODUCTION
In Wartsila 26 Project Guide, the compressed air system is explained by this
statement :
Compressed air is used to start engines and to provide actuating energy for safety
and control devices. The use of starting air for other purposes is limited by the
classification regulations. To ensure the functionality of the components in the
compressed air system, the compressed air has to be free from solid particles and
oil.
II. OBJECTIVES
The objective of this chapter are :
a) Knowing the components and function of the Compressed Air System
b) Knowing the specification of pumps ad equipment used.
III. REFERENCES
a) ClassNK Part D, Chapter 13, Piping System
b) Project Guide Wartsila 26
No Abbreviations Explanation
1 kPa Kilo Pascal
2 t Time
3 mm Milimeter
4 h Hour
5 kW Kilowatt
6 RPM Radian per Minute
7 v Velocity
8 Q Capacity
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V. SYSTEM DESCRIPTION
Compressed air is used to start engines and to provide actuating energy for safety
and control devices. The use of starting air for other purposes is limited by the
classification regulations.
To ensure the functionality of the components in the compressed air system, the
compressed air has to be free from solid particles and oil.
The design of the starting air system is partly determined by classification
regulations. Most classification societies require that the total capacity is divided
into two equally sized starting air receivers and starting air compressors. The
requirements concerning multiple engine installations can be subject to special
consideration by the classification society.
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VI. DESIGN REQUIREMENTS
Key
No Reference Parameter Design
Equipment
Air compressors are to be so arranged that entry of
oil into inlet air may be minimized as practicable.
Each air compressor is to be provided with a relief
valve to prevent the pressure from rising more than
Class NK Part
10% above its maximum working pressure in
D Chapter
cylinders.
13.13.1
Arrangment Where water jackets of air coolers might be subject
of Air to dangerous excessive pressure due to leakage of
Compresse compressed air into them, suitable pressure relief
1 r and arrangement is to be provided for the water jackets.
Pressure Where the main propulsion machinery is designed
Relief for starting by compressed air, two or more starting
System air compressors are to be provided and arranged so
Class NK Part as to be able to charge each air reservoir.
D Chapter The total capacity of air compessor is to be
13.13.3 sufficient to supply air in the air reservoirs from
atmospheric pressure to the pressure requires for
the consecutive starts prescribed in 2.5.3-2 within
one hour
Starting air pipes from the air reservoirs to the main
propulsion machinery or auxiliary engines are to be
entirely separate from the compressor discharge
system prescribed in -2.
The prime movers driving the emergency air
Emergency
Class NK Part compessor are to be capable of starting without
Air
2 D Chapter compressed air.
Compresso The capacity of the emergency air compressor is to
13.13.4
rs be sufficient to start the prime movers of the air
compressor prescribed in 13.13.3. For this
purpose, a small air reservoir for emergency air
compressor may be provided.
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Drainage system is to be provided to compressed
air piping containing drain inside the pipes.
All discharging pipes to starting air reservoirs are to
Class NK Part be led directly from starting air compressors.
3 Piping D Chapter Starting air pipes from the air reservoirs to the main
13.13.5 propulsion machinery or auxillary engines are to be
entirely separate from the compressore discharge
system.
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At least two starting air compressors must be
installed. It is recommended that the compressors
are capable of filling the starting air vessel from
Starting Air
Wartsilla 26 minimum (1.8 MPa) to maximum pressure in
7 Compresso
Project Guide 15...30 minutes.For exact determination of the
r
minimum capacity,the rules of the classification
societies must be followed.
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VII. SUMMARY OF CALCULATION
b. Air Receiver
BRAND = Mellcon SL 3
Volume = 500 liter
Height = 1550 mm
Diameter = 600 mm
Max Pressure = 30 bar
b. Compressor Selection
BRAND = Hatlapa RPM = 1150
Type = L9 Frequency = 50 Hz
Capacity = 6.6 m3/h Phase = 3
Power = = 1.7 kW Voltage = 380 V
So, based on calculation the sepesification of starting air vessel choosen is:
Starting Air Vessel Dimension
Merk Mellcon SL 3 Height 1550 mm
Type Vertical Diameter 600 mm
Volume 500 Liter
Max Press. 30 Bar
c. Calculation Capacity of Compressor
At least two starting air compressors must be installed. It is recommended that the
compressors are capable of filling the starting air vessel from minimum (1.8 MPa) to
maximum pressure in 15...30 minutes. For exact determination of the minimum
capacity, the rules of the classification societies must be followed.
The formula is:
𝑉
𝑄 =
𝑡
Where,
● V = Volume of Starting Air Vessel
= 0.90 m3
● t = 15 Minutes
= 0.25 Hour
So, The Capacity of Compressor is:
Q = 0.9
0.25
= 3.60 m3
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4. SPEFICATION OF EQUIPMENT
A. Air Reciever
B. Compressor