Tutorial Depressuring Second [Compatibility Mode]
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Transcript of Tutorial Depressuring Second [Compatibility Mode]
Fill Depressuring Inventory Data
Calculate the wetted area based on this size.Then, Compare with the actual wetted area
HYSYSLiquid percent = 35.6 %Wetted height = (35.6 / 100) * 11.37Wetted Area = 96 ft2 (8.9 m2)
ACTUAL
Process System2
Checking the wetted area of this model, will result the wetted area is different with the actual wetted area The model volume is good enough but sometimes the wetted area is not match with the real condition.
ACTUAL Wetted Area = 155 ft2 ( 14.4 m2)
To be applied only if heat flux of 21.000 BTU/hr ft^1.64 orQ = : Q = 21000FA^0.82
Other cases , such as *)1. For system with adequate draining
and fire fighting do not exist, the heat flux is 34500 BTU/hr.ft^1.64 C1 = 34500
2. Jet fire , the heat flux is 95,500
C2 is locked, we cannot use this value for jet fire and when fraction area 1.0 ( in small
CHECK !
Fill Depressuring HEAT FLUX of FireAPI521
Process System3
2. Jet fire , the heat flux is 95,500 BTU/ft2/hr.C1 = 95,500
2. For small system, the fraction area exposed by fire is 1.0 instead of 0.82C2 = 1
3. For vessel with insulation, or covered by earth, the environment factor less than 1.0ex = 0.3
fraction area 1.0 ( in small system)
Double click the sub flow sheet of depressuring � go to sub-flow sheet environment � double click Duty spreadsheet
CHECKING HEAT FLUX Correlation
Process System4
Lets checking this spreadsheet after running …
Sometimes, this wetted area is different with the actual data.
CHECKING HEAT FLUX Correlation after Running With input data heat flux of 21000 btu/ft^1.64/hr(POOL FIRE CASE).Unit is already consistent .
Sometimes, this wetted area is different with the actual data.
Process System5
different with the actual data.
With input data heat flux of 34500 btu/ft^1.64/hr(POOL FIRE – DRAINAGE DO NOT EXIST). Unit is already consistent
With input data heat flux of 94500 btu/ft2/hr ( = 300 kW/m2)(JET FIRE CASE ).Unit is NOT consistent.
Process System6
1. JET FIRE consider less wetted area than pool fire.
2. Use one biggest equipment for the wetted area consideration
C2 = 1 for jet fire
With input data heat flux of 300000
Input C1 = 300 000 W/m2 instead of 94500 btu/ft2/hr
Process System7
With input data heat flux of 300000 W/m2( = 300 kW/m2)(JET FIRE CASE ) Unit is consistent.
Now ,,We GET the PROBLEM.
1. HYSYS Depressuring Utility does not have Jet fire case
2. The Wetted Area not match with the real condition
Process System8
Click view spreadsheet � go to spreadsheet
Spreadsheet method
Unit area in m2, thereforeInput C1 = 300 kW/m2C2 = 1
Process System9
C2 = 1C3 = 1
Cannot be changed
Select connections page and delete ‘Cell D8’ for tank wetted area.
DELETE : tank wetted area D8
Back to spreadsheet
Process System10
Now, the wetted area can be revised based on actual data
Input = 1, ���� FireAPI 521 method is Applied
VERYFY RESULT
View Historical Data
Wetted area match
Process System11
Wetted area match with the actual data
# Wetted Area = 14.4 m2# Duty = 300 x 1 x 14.4
= 4320 kW
In Hysys Depressuring utility, the model is only specified as one horizontal
or vertical vessel. Dimension of that single vessel, is back calculated
based on total liquid and vapour volume. Wetted area calculation is
difficult for horizontal vessel. It is very difficult to match wetted area and
liquid volume of vessel with wetted area and volume of a real system.
HYSYS also provided fire case of pool fire and doesn’t have Jet fire case.
SUMMARY
Process System12
HYSYS also provided fire case of pool fire and doesn’t have Jet fire case.
To overcome this problem, we can use spreadsheet method as explained
in this tutorial.
Process System13