Asumsi 1. Kebutuhan steam yang dihitung adalah steam untuk meningkat temperature ke 2. Penurunan temperatur sehingga mengharuskan pemanasan adalah 5 C 3. Volume oil yang dipanaskan diasumsikan 155 m3 yang merupakan volume maksim Kalkulasi Kebutuhan Steam per Tangki MFO Initial T 60 C Final T 65 C Heating time 5 hr Maintain T 65 C Wind velocity 10.08 km/h 6.25 mph Ambient T 27.4 C 81.32 F Diameter 6.8 m Height 6.04 m h 1.7 m Tank manhole 20 in 0.508 m Volume oil 155 m3 Delta T 5K Faktor 1 Data Cp, MFO 2.09 kJ/kg K Densitas MFO 988.8 kg/m3 Pressure Steam 8 bar Latent heat 2768.3 kJ/kg 873 Btu/lb Basic Data Calculation Tank capacity 219 m3 153266 kg 62.5 C 144.5 F Tank wall area 129 m2 1387 ft2 Tank roof area 41 m2 437 ft2 Heat up Load Heat up load 320,326 kJ/hr 305,072 Btu/hr Tank wall heat loss 120 Btu/hr/ft2 2 Weight of fluid in tank Average liquid temperature Tank wall heat loss Wind velocity correction
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Asumsi1. Kebutuhan steam yang dihitung adalah steam untuk meningkat temperature ke temperatur maintenance dan steam yang dibutuhkan untuk meningkatkan temperatur mula-mula 155 m3 fuel oil2. Penurunan temperatur sehingga mengharuskan pemanasan adalah 5 C3. Volume oil yang dipanaskan diasumsikan 155 m3 yang merupakan volume maksimal tangki
Kalkulasi Kebutuhan Steam per Tangki MFO
Initial T 60 CFinal T 65 CHeating time 5 hrMaintain T 65 CWind velocity 10.08 km/h
Kebutuhan steam satu tangki Kebutuhan steam dua tangki
Volume MFO yang akan dipanaskan (m3)
Kons
umsi
stea
m (k
g/hr
)
Asumsi:- Peningkatan temperatur 5 C- Waktu pemanasan 5 jam
0 30 60 90 120 150 180 -
50
100
150
200
250
300
350
400
450
Kebutuhan steam satu tangki Kebutuhan steam dua tangki
Volume MFO yang akan dipanaskan (m3)
Kons
umsi
stea
m (k
g/hr
)
1. Kebutuhan steam yang dihitung adalah steam untuk meningkat temperature ke temperatur maintenance dan steam yang dibutuhkan untuk meningkatkan temperatur mula-mula 155 m3 fuel oil
I. Inlet and Outlet Pressure Condition of the trap
Inlet Pressure
10 bargInlet pressure to control valve 8.000 bargPressure drop in coil 0.005 barg
7.995 bargPressure drop in coil 0.005 bargInlet pressure to steam trap 7.990 barg
Outlet Pressure
Outlet pressure 0 barg Atmospheric tank system-gravity drainage(see Equipment Type 1, Class A)
Differential Pressure
Differential pressure 7.990 barg115.86 psig
II. Condensate Load Calculation
Asumsi
Pemanasan dalam tangki diasumsikan hanya disebabkan oleh heat loss dari tangki karena pengaruh lingkungan
Heat loss
Tank wall heat loss 66,181.43 Btu/hrTank roof heat loss 10,412.93 Btu/hrTotal tank heat loss 76,594.36 Btu/hr
Condensate load
Condensate load 87.74 lb/hr 39.48 kg/hr
III. Safety factor
Safety factor 3 see matrix
IV. Desired Trap Capacity
Desired trap capacity each tank 118.44 kg/hr
Maximum pressure in steam line supply
Outlet pressure from control valve to coil
V. Available Steam Trap Capacity
See graphic below
Discharge capacity 350 kg/hr (Hot condensate near steam temperature)Discharge capacity 3300 kg/hr (Cold water 21 C)
VI. Selection Criteria
Mechanical Thermostatic Thermodynamic
First level criteria
Safety P P PEfficiency P P PService life P P P
Second level criteria
Ease of checking
7.99 psig
116 psig
Sensitivity to backpressure
Resistance to freeze damage
Dirt sensitivity
Installation versatility
Air venting
Responsiveness to changing load Very responsive Very responsive
Predominant failure mode
Discharge mode
Tend to decline in efficiency as backpressure exceed 50% of the inlet pressure
Mechanical traps do not easily lend themselves to flexibility of use
Some models can be installed successfully in horizontal or vertical line
Some models can be installed successfully in horizontal or vertical line
Pass air very quicly
Thermodynamic disc trap and bucket trap release air much more slowlyy
Must first cool slightly before they can open wider to pass a greater amount of condensate
Resistance to shock vibration and water hammer
The closed-float are fragile and damage-prone
Bimetallic thermostatic generally are very rugged
Generally are very rugged
Bellows thermostatic trap will fail either open or closed (depending on the design of bellows)
Thermodynamic and bimetal trap fail open when they are worn out
Cyclic thermodynamic disc and bucket trap are easier to check for proper maintenance and better at passing dirt particles
Condensate discharge temperature relative to saturation curve
Most thermodynamic trap follows saturation curve closely
Ease of maintenance
Third level criteria
Product availability
Post-sales service
Warranty
Price
Magniture of condensate sub-cooling
Supplementing accessories or features
Atmospheric tank system-gravity drainage(see Equipment Type 1, Class A)
Pemanasan dalam tangki diasumsikan hanya disebabkan oleh heat loss dari tangki karena pengaruh lingkungan
(Hot condensate near steam temperature)
Note
When properly sized and installed
When properly sized and installed
When properly sized and installed
350
The faster the air is vented, the more quickly equipment is brought up to temperature
A trap that fails open is more desirable than one that fails closed in order to preserve the process
Continuous draining float trap is especially responsive to rapidly changing condensate loads and does not contribute to pressure surges in return system
A trap with little subcooling will discharge condensate within 2-3 degrees of steam temperature, while a trap with large subcooling will discharge condensate with 30 or more degree F of steam temperature. It is desirable to discharge condensate as soon as it forms to achieve steady temperature control