June 16, 2011 Piruz Nezami
Overview
•
Introduction – Definitions and Functions
•
Design Parameters
•
Sizing Bases and Equations
•
API 521 Sample Calculation
•
Spreadsheet
1
Introduction API 521 - ISO 23251 Definition: Vessel in the effluent handling system designed to remove and store liquids. Function of Flare Knockout Drum: To separate liquid from gas and hold maximum amount of liquid relieved in an emergency. KO drum is typically located close to the flare stack upstream of any liquid seal. Unit knockout drums: For process units which possibly release large amount of liquid, it is desirable to have local KO drums inside the battery limit. This reduces the sizing requirements for the main flare knockout drum. Knockout drum can be horizontal or vertical. 2
Design Parameters 1.
Liquid droplet size limited to 300 to 600 µm to avoid burning liquid outside the flame envelope.
2.
Maximum liquid hold up must be considered for vapor-liquid disengagement calculations.
3.
In addition to liquid holdup, liquids that previously accumulated in the drum and not pumped out (slop) should be taken into account.
4.
API 521 recommends a minimum of 20 to 30 minutes holdup time. Longer Holdup might be required if it takes longer to stop flow.
5.
Maximum vapor release may not coincide with the maximum liquid release.
3
Design Parameters 6.
Typically the relief rates (not rated capacities) used for flare header, flare tip, and knockout drum design.
7.
It is normally not necessary to size local knockout drums for efficient vapor-liquid separation at maximum flow rate.
8.
The economics of the drum design can influence the choice between horizontal and vertical drums. ●
Horizontal drums are more suitable for large liquid capacity and high vapor flow. They have lower pressure drop than vertical drums.
●
Vertical drums are typically used when the liquid load is low or limited plot space is available.
4
Design Parameters 9.
Nozzle Configurations: a)
Horizontal Drums: ●
Vapor entering at one end and exiting at the top of the opposite end.
●
Vapor entering at each end and exiting at the center.
● Vapor entering at the center and exiting at each end of the drum. b)
Vertical Drums: ●
Vapor entering radially and exiting at the top of the drum. A baffle is required to direct the flow downward.
●
Vapor entering tangentially and exiting at the top of the drum. 5
Knockout Drum Sizing Sizing a knockout drum is a trial-and-error process. 1st step is to determine drum size for liquid separation. Liquid particles separate: When vapor velocity is sufficiently low to allow the liquid dropout to fall. When the vapor residence time is equal or greater than the time required for the liquid particles to travel the available height at dropout velocity (liquid dropout time). The vertical height is usually taken as the distance from the top of the drum to the maximum liquid level.
6
Vapor Travel - Liquid Dropout Nozzle to Nozzle Distance, L N
HV
High Liquid Level HL
L TV = N VV T V : Vapor Residence Time L N : KO Drum Nozzle to Nozzle Length V V : Vapor Velocity
TD =
HV VD
T D : Liquid Dropout Time H V : Vapor Space Height V D : Liquid Dropout Velocity
7
Horizontal Knockout Drum Sizing Liquid Dropout Velocity:
g D (ρ L − ρV ) V D = 1.15 ρV C VD :
Liquid Dropout Velocity
g:
Gravitational Constant (9.8 m/s2, 32.2 ft/s2)
D:
Particle Diameter
ρL :
Liquid Density at Operating Conditions
ρV :
Vapor Density at Operating Conditions
C:
Drag Coefficient
8
Horizontal Knockout Drum Sizing Drag Coefficient:
(Cte ) ( ρV ) ( D )3 ( ρ L − ρV ) (C ) (Re) = ( µ )2 2
Re : Reynolds Number µ:
Vapor Viscosity at Operating Conditions
Cte : Constant (0.13 x 108 in Metric and 0.95 x 108 in Imperial Units)
9
API 521 – ISO 23251 Sample Calculation Total Flow Rate:
200,000 lb/hr
Liquid Density
31 lb/ft3
Vapor Density
0.18 lb/ft3
Pressure:
2 psig
Temperature:
300 °F
Vapor Viscosity:
0.01 cP
The liquid equilibrium results in 31,000 lb/hr of liquid and 169,000 lb/hr of vapor. In addition, 500 gallons of storage for miscellaneous drainings from the unit is desired. The maximum allowable droplet size is 300 µm. 10
API 521 – ISO 23251 Sample Calculation
RV= 169,000 / (3,600 x 0.18)
Actual Vapor Rate Drag Coefficient x Re2
C x Re2= [ 0.95 x 108 x 0.18 x (0.000984)3 x (31 - 0.18) ] / (0.01)2
Dropout Velocity
UC= 1.15 * [ 32.2 X 0.000984 x (31 - 0.18) / (0.18 x 1.3) ]0.5
Slop Cross Sectional Area
AS= 66.8 (ft3) / L (ft)
Holdup Cross Sectional Area
AH= (31,000 / 31) x (30/60) (ft3) / L (ft)
Drum Cross Sectional Area
AT= π x D2 / 4
Vapor Cross Sectional Area
AV= AT - AS - AH
11
= = =
261 ft3/sec 5,021 2.35 ft/sec
API 521 – ISO 23251 Sample Calculation
AV
HH
HT (D) α β
1 AH + AS = × [ β − Sin (β ) ] × D 2 8
AH
HH
AS =
AS
HS
12
1 × [ α − Sin (α ) ] × D 2 8
API 521 – ISO 23251 Sample Calculation
Diameter Length
Cross Sectional Area
Vertical Height
Dropout
Vapor Minimum
D
L
AT
AS
AH
AV
HT (D)
HS + HH
HV
ft
ft
ft2
ft2
ft2
ft2
in
in
in
sec
ft/sec
ft
1
8.0
19.0
50.27
3.52
26.32
20.43
96.0
55.0
41.0
1.45
12.76
18.5
2
7.5
20.5
44.18
3.26
24.39
16.53
90.0
54.0
36.0
1.28
15.78
20.2
3
7.0
22.5
38.48
2.97
22.22
13.29
84.0
52.3
31.7
1.13
19.62
22.1
4
6.5
25.0
33.18
2.67
20.00
10.51
78.0
50.0
28.0
0.98
24.82
24.3
Case No
13
Time, TD Vel, VV Length, L
API 521 Sample calculation FLARE KNOCK OUT DRUM
PROG NO: JE-103 05/22/2011
JACOBS
Prepared By:
Date:
Project:
API 521 SAMPLE CALCULATION - 1
Checked By:
Job No:
XXXXX-100
R
Subject:
FLARE KNOCK OUT DRUM
Tag No:
V-XXXX
E
Calc No:
XXX-XXXX-XXXXX-000
Client:
1
DESCRIPTION
2
Drum Temperature, t
3
Drum Pressure, P
4
Estimated L/D Ratio, R E Mass Flow Rate, M V
6
Molecular Weight, MW V
7 8
VAPOR
5
9
Compressibility Factor, Z V
File No:
UNIT °F
XXX-XXXX-XXXXX-000 VALUE 300.0
psi-g
2.0
--
2.44
lb/hr
169,000
lb/lbmole --
Sheet:
1
of
Temperature
°F
Pressure
psi
Mass Flow Rate
lb/hr
Liquid Volumetric Flow Rate
ft³/hr
Vapor Volumetric Flow Rate
ft³/hr
Density
lb/ft³
Density, ρ V
lb/ft³
0.180
Dimension
ft
Viscosity, µV
cP
0.010
Area
ft²
Liquid Volume
ft³
lb/hr
31,000
11
Density, ρ L
lb/ft³
31.0
Velocity
ft/sec
micron
300
Viscosity
cP
ft³
66.8
Nozzle Diameter
in
13
LIQUID
Mass Flow Rate, M L Maximum Droplet Size, d M Slop Capacity, V S
14
Holdup Time, (Slop Level to NLL), T H
minute
30
15
Additional Holdup Volume to HLL, V XL
ft³
0.0
14
V
UNITS OF MEASUREMENT
10
12
1
Single Entry
TRUE
SELECTED DRUM DIMENSIONS
Dual Entry
FALSE
UNIT
VALUE
API 521 Sample Calculation 16
Vapor Density, ρV
lb/ft³
17
Volumetric Vapor Rate, Q V
ft³/hr
18
Liquid Holdup Capacity
ft³
19
Calculated Drum Diameter, D C
ft
20
Calculated Minimum Drum Length (T/T), L C
ft
21
Slop Height from Bottom, H SC
22
0.180 KO Drum Pump(s) Capacity
100.00
--
No
micron
303
ft
8.00
19.11 Selected Drum Length (T/T), L S
ft
18.50
ft
0.98 Slop Height from Bottom, H SS
ft
1.00
Liquid Holdup Height from Bottom (NLL), H NC
ft
4.63 Liquid Holdup Ht (Normal Level), H NS
ft
4.69
23
High Liquid Level Height from Bottom, H LC
ft
4.63 High Liquid Level Height, H LS
ft
4.69
24
Liquid Dropout Velocity, V DC
ft/sec
2.35 Liquid Dropout Velocity, V DS
ft/sec
2.38
25
Liquid Dropout Time, T DC
sec
1.37 Liquid Dropout Time, T DS
sec
1.39
26
Vapor Space Height, H VC
ft
3.22 Vapor Space Height, H VS
ft
3.31
27
Vapor Space Cross Sectional Area, A VC
ft²
18.7 Vapor Space Cross Sectional Area, A VS
ft²
19.6
28
Vapor Velocity, V VC
ft/sec
13.95 Vapor Velocity, V VS
ft/sec
13.29
29
--
5,025 C ( Re ) 2 1.298 Drag Coefficient, C S
--
5,180
30
C ( Re ) 2 Drag Coefficient, C C
--
1.284
31
Convergence Absolute Tolerance
ft
--
2.00
--
938,889 Does Second Pump Start at HLL?
ft³/hr
500.0 Droplet Size for Selected Dimensions, d S 7.85 Selected Drum Diameter, D S
0.00E+00 Iteration Weight
15
API 521Sample Calculation 32
Nozzle Centerline to Tangent
33
Nzzl. Centerline to Tan. ft
34
18.50 ft
ft
Inlet Nozzle Dia, in:
35
Outlet Nzzle Dia, in:
12.00
12.00
36 37
Liq Levels From Bottom
( ft )
Section Vol
38
HHLL (ESD)
4.49
( ft³ )
Incoming
Outgoing (2)
Note 3
39
Residence Time, minute
Vapor Space
HLL (2nd Pump Starts)
4.69
-29.5
-1.8
-17.7
-2.0
40
NLL (1st Pump Starts)
4.69
0.0
0.0
0.0
0.0
Add Holdup
41
Slop Level
1.00
500.0
30.0
300.0
33.3
Liq Holdup
42
LLL (Both Pumps Stop)
0.00
66.8
4.0
40.1
4.5
Slop Cap
0.0
0.0
0.0
0.0
Dead Vol
8.0 ft
43 44
18.50 ft
45 46
NOTES
47
1. Do NOT link entry cells (cells highlighted blue) to other cells. These cells SHOULD contain a numeric value.
48
2. Residence time for each section based on the capacity of one pump.
49
3. This is the residence time for each section based on the balance of the incoming liquid flow and the outgoing pump-out rate by one pump.
50
Negative numbers (if applicable) mean the pump-out rate is greater than the incoming flow rate.
51 52 53
16
Knockout Drum Spreadsheet - 1 FLARE KNOCK OUT DRUM Client:
JACOBS
Project:
API 521 SAMPLE CALCULATION - 1
Subject:
FLARE KNOCK OUT DRUM
Calc No:
XXX-XXXX-XXXXX-000
1
DESCRIPTION
2
Drum Temperature, t
3
Drum Pressure, P
4
Estimated L/D Ratio, R E Mass Flow Rate, M V
6
Molecular Weight, MW V
7 8
VAPOR
5
9
File No:
UNIT °F
XXX-XXXX-XXXXX-000 VALUE 300.0
psi-g
2.0
--
2.44
lb/hr
169,000
lb/lbmole
Compressibility Factor, Z V
--
Density, ρ V
lb/ft³
0.180
Viscosity, µV
cP
0.010
Mass Flow Rate, M L
lb/hr
31,000
11
Density, ρ L
lb/ft³
31.0
micron
300
ft³
66.8
12 13
LIQUID
10
Maximum Droplet Size, d M Slop Capacity, V S
14
Holdup Time, (Slop Level to NLL), T H
minute
30
15
Additional Holdup Volume to HLL, V XL
ft³
0.0
17
Knockout Drum Spreadsheet - 2 16
Vapor Density, ρV
lb/ft³
0.180
17
Volumetric Vapor Rate, Q V
ft³/hr
938,889
18
Liquid Holdup Capacity
ft³
500.0
19
Calculated Drum Diameter, D C
ft
7.85
20
Calculated Minimum Drum Length (T/T), L C
ft
19.11
21
Slop Height from Bottom, H SC
ft
0.98
22
Liquid Holdup Height from Bottom (NLL), H NC
ft
4.63
23
High Liquid Level Height from Bottom, H LC
ft
4.63
24
Liquid Dropout Velocity, V DC
ft/sec
2.35
25
Liquid Dropout Time, T DC
sec
1.37
26
Vapor Space Height, H VC
ft
3.22
27
Vapor Space Cross Sectional Area, A VC
ft²
18.7
28
Vapor Velocity, V VC
ft/sec
13.95
29
--
5,025
30
C ( Re ) 2 Drag Coefficient, C C
--
1.298
31
Convergence Absolute Tolerance
ft
0.00E+00
18
Knockout Drum Spreadsheet - 3 SELECTED DRUM DIMENSIONS
UNIT
VALUE
KO Drum Pump(s) Capacity
ft³/hr
100.00
Does Second Pump Start at HLL?
--
No
micron
303
Selected Drum Diameter, D S
ft
8.00
Selected Drum Length (T/T), L S
ft
18.50
Slop Height from Bottom, H SS
ft
1.00
Liquid Holdup Ht (Normal Level), H NS
ft
4.69
High Liquid Level Height, H LS
ft
4.69
Liquid Dropout Velocity, V DS
ft/sec
2.38
Liquid Dropout Time, T DS
sec
1.39
Vapor Space Height, H VS
ft
3.31
Vapor Space Cross Sectional Area, A VS
ft²
19.6
Vapor Velocity, V VS
ft/sec
13.29
C ( Re ) 2 Drag Coefficient, C S
--
5,180
--
1.284
Iteration Weight
--
2.00
Droplet Size for Selected Dimensions, d S
19
Knockout Drum Spreadsheet - 4 32
Nozzle Centerline to Tangent
33
Nzzl. Centerline to Tan. ft
34
18.50 ft
ft
Inlet Nozzle Dia, in:
35
Outlet Nzzle Dia, in:
12.00
12.00
36 37
Liq Levels From Bottom
( ft )
Section Vol
38
HHLL (ESD)
4.49
( ft³ )
Incoming
Outgoing (2)
Note 3
HLL (2nd Pump Starts)
4.69
-29.5
-1.8
-17.7
-2.0
40
NLL (1st Pump Starts)
4.69
0.0
0.0
0.0
0.0
Add Holdup
41
Slop Level
1.00
500.0
30.0
300.0
33.3
Liq Holdup
42
LLL (Both Pumps Stop)
0.00
66.8
4.0
40.1
4.5
Slop Cap
0.0
0.0
0.0
0.0
Dead Vol
39
8.0 ft
43 44
Residence Time, minute
18.50 ft
45 46
NOTES
47
1. Do NOT link entry cells (cells highlighted blue) to other cells. These cells SHOULD contain a numeric value.
48
2. Residence time for each section based on the capacity of one pump.
49
3. This is the residence time for each section based on the balance of the incoming liquid flow and the outgoing pump-out rate by one pump.
50
Negative numbers (if applicable) mean the pump-out rate is greater than the incoming flow rate.
51 52 53
20
Vapor Space
Spreadsheet Features UOM UNITS OF MEASUREMENT Temperature
°F
Pressure
psi
Mass Flow Rate
lb/hr
Liquid Volumetric Flow Rate
ft³/hr
Vapor Volumetric Flow Rate
ft³/hr
Density
lb/ft³
Dimension
ft
Area
ft²
Liquid Volume
ft³
Velocity
ft/sec
Viscosity
cP
Nozzle Diameter
in
Single Entry
Dual Entry
TRUE
21
FALSE
Spreadsheet Features UOM
22
Spreadsheet Features – UOM
23
Features – Number of Entry Nozzles in
Nozzle Diameter Single Entry
Dual Entry
TRUE
SELECTED DRUM DIMENSIONS
FALSE
UNIT
VALUE
Nozzle Centerline to Tangent
Nzzl. Centerline to Tan. ft
18.50 ft
ft
Inlet Nozzle Dia, in:
Outlet Nzzle Dia, in:
12.00
8.0 ft
12.00
Liq Levels From Bottom
( ft )
Section Vol
HHLL (ESD)
4.49
( ft³ )
Incoming
Outgoing (2)
Note 3
HLL (2nd Pump Starts)
4.69
-29.5
-1.8
-17.7
-2.0
NLL (1st Pump Starts)
4.69
0.0
0.0
0.0
0.0
Add Holdup
Slop Level
1.00
500.0
30.0
300.0
33.3
Liq Holdup
LLL (Both Pumps Stop)
0.00
66.8
4.0
40.1
4.5
Slop Cap
0.0
0.0
0.0
0.0
Dead Vol
18.50 ft
24
Residence Time, minute
Vapor Space
Features – Number of Entry Nozzles in
Nozzle Diameter Single Entry
Dual Entry
FALSE
SELECTED DRUM DIMENSIONS
TRUE
UNIT
VALUE
Nozzle Centerline to Tangent
Nzzl. Centerline to Tan. ft
18.50 ft
0.00
ft
Inlet Nozzles Dia, in: 12.00 Outlet Nzzle Dia, in:
8.0 ft
12.00
Liq Levels From Bottom
( ft )
Section Vol
HHLL (ESD)
4.49
( ft³ )
Incoming
Outgoing (2)
Note 3
HLL (2nd Pump Starts)
4.69
-29.5
-1.8
-17.7
-2.0
NLL (1st Pump Starts)
4.69
0.0
0.0
0.0
0.0
Add Holdup
Slop Level
1.00
500.0
30.0
300.0
33.3
Liq Holdup
LLL (Both Pumps Stop)
0.00
66.8
4.0
40.1
4.5
Slop Cap
0.0
0.0
0.0
0.0
Dead Vol
18.50 ft
25
Residence Time, minute
Vapor Space
Features – Iterative Calculations Calculated Values Entered Data 1
DESCRIPTION
2
Drum Temperature, t
3
Drum Pressure, P
4
Estimated L/D Ratio, R E
16
Vapor Density, ρV
lb/ft³
0.180
VALUE
17
Volumetric Vapor Rate, Q V
ft³/hr
938,889
°F
300.0
18
Liquid Holdup Capacity
ft³
500.0
bar-g
0.138
19
Calculated Drum Diameter, D C
ft
7.85
--
2.44
20
Calculated Minimum Drum Length (T/T), L C
ft
19.11
169,000
21
Slop Height from Bottom, H SC
ft
0.98
22
Liquid Holdup Height from Bottom (NLL), H NC
ft
4.63
23
High Liquid Level Height from Bottom, H LC
ft
4.63
24
Liquid Dropout Velocity, V DC
ft/sec
2.35
25
Liquid Dropout Time, T DC
sec
1.37
26
Vapor Space Height, H VC
ft
3.22
ft²
18.7
UNIT
Mass Flow Rate, M V
6
Molecular Weight, MW V
lb/lbmole
Compressibility Factor, Z V
--
7 8
VAPOR
5
9
lb/hr
Density, ρ V
lb/ft³
0.180
Viscosity, µV
cP
0.010
Mass Flow Rate, M L
lb/hr
31,000
11
Density, ρ L
lb/ft³
31.0
micron
300
27
Vapor Space Cross Sectional Area, A VC
ft³
66.8
28
Vapor Velocity, V VC
ft/sec
13.95
--
5,025
--
1.298
ft
0.00E+00
12 13
L IQ U ID
10
Maximum Droplet Size, d M Slop Capacity, V S
14
Holdup Time, (Slop Level to NLL), T H
minute
30
29
15
Additional Holdup Volume to HLL, V XL
ft³
0.0
30
C ( Re ) 2 Drag Coefficient, C C
31
Convergence Absolute Tolerance
26
Features – Convergence FLARE KNOCK OUT DRUM
PROG NO: JE-103 05/08/2011
Converg.
Area
Check
Tolerance
JACOBS
Prepared By:
Date:
Project:
API 521 SAMPLE CALCULATION - 1
Checked By:
Job No:
XXXXX-100
R
FALSE
8.96E-05
Subject:
FLARE KNOCK OUT DRUM
Tag No:
V-XXXX
E
FALSE
-6.86E-10
Calc No:
XXX-XXXX-XXXXX-000
V
FALSE
-9.89E-10
FALSE
9.89E-10
Client:
1
DESCRIPTION
2
Drum Temperature, t
3
Drum Pressure, P
4
Estimated L/D Ratio, R E
File No:
UNIT
Molecular Weight, MW V
lb/lbmole
Compressibility Factor, Z V
--
VAPO R
6
9
Density, ρ V
lb/ft³
Viscosity, µV
cP
of
1
FALSE
Converg.
psi
FALSE
Tolerance
lb/hr
FALSE
5.56E-09
169,000 Liquid Volumetric Flow Rate
gpm
FALSE
0.00E+00
79.11 Vapor Volumetric Flow Rate
ft³/hr
FALSE
4.11E-15
0.900 Density
lb/ft³
FALSE
-3.55E-15
ft
FALSE
ft²
FALSE
ft³
FALSE
2.0 Pressure
lb/hr
1
°F
psi-g --
Sheet:
UNITS OF MEASUREMENT
300.0 Temperature
Mass Flow Rate, M V
8
VALUE
°F
5
7
XXX-XXXX-XXXXX-000
2.44 Mass Flow Rate
Dimension 0.010 Area
Mass Flow Rate, M L
lb/hr
11
Density, ρ L
lb/ft³
31.0 Velocity
ft/sec
FALSE
micron
300 Viscosity
cP
FALSE
66.8 Nozzle Diameter
in
12 13
L IQ U ID
10
Maximum Droplet Size, d M Slop Capacity, V S
ft³
14
Holdup Time, (Slop Level to NLL), T H
minute
15
Additional Holdup Volume to HLL, V XL
ft³
16
Vapor Density, ρV
lb/ft³
17
Volumetric Vapor Rate, Q V
ft³/hr
31,000 Liquid Volume
30
Single Entry
FALSE
26.7 SELECTED DRUM DIMENSIONS 0.180 KO Drum Pump(s) Capacity 938,839 Does Second Pump Start at HLL?
FALSE
Dual Entry
TRUE
FALSE
UNIT
VALUE
FALSE
gpm
12.47
FALSE
No
FALSE
--
Keep Hitting F9 till all the Convergence Checks turns “True” 27
Features – Convergence FLARE KNOCK OUT DRUM
PROG NO: JE-103 05/22/2011
Converg.
Area
Check
Tolerance
JACOBS
Prepared By:
Date:
Project:
API 521 SAMPLE CALCULATION - 1
Checked By:
Job No:
XXXXX-100
R
TRUE
0.00E+00
Subject:
FLARE KNOCK OUT DRUM
Tag No:
V-XXXX
E
TRUE
0.00E+00
Calc No:
XXX-XXXX-XXXXX-000
V
TRUE
0.00E+00
Client:
1
DESCRIPTION
2
Drum Temperature, t
3
Drum Pressure, P
4
Estimated L/D Ratio, R E Mass Flow Rate, M V
6
Molecular Weight, MW V
7 8
VA PO R
5
9
Compressibility Factor, Z V
File No:
UNIT °F bar-g -lb/hr
XXX-XXXX-XXXXX-000 VALUE
Viscosity, µV
cP
of
1
UNITS OF MEASUREMENT
TRUE TRUE
Converg.
0.138 Pressure
bar
TRUE
Tolerance
lb/hr
TRUE
0.00E+00
169,000 Liquid Volumetric Flow Rate
ft³/hr
TRUE
0.00E+00
Vapor Volumetric Flow Rate
ft³/hr
TRUE
0.00E+00
Density
lb/ft³
TRUE
0.00E+00
0.180 Dimension
ft
TRUE
0.010 Area
ft²
TRUE
ft³
TRUE
2.44 Mass Flow Rate
Mass Flow Rate, M L
lb/hr
11
Density, ρ L
lb/ft³
31.0 Velocity
ft/sec
TRUE
micron
300 Viscosity
cP
TRUE
in
TRUE
13
LIQ U ID
10
12
Maximum Droplet Size, d M Slop Capacity, V S
ft³
14
Holdup Time, (Slop Level to NLL), T H
minute
15
Additional Holdup Volume to HLL, V XL
ft³
16
Vapor Density, ρV
lb/ft³
17
Volumetric Vapor Rate, Q V
ft³/hr
0.00E+00
°F
-lb/ft³
1
300.0 Temperature
lb/lbmole
Density, ρ V
Sheet:
31,000 Liquid Volume
66.8 Nozzle Diameter 30
Single Entry
FALSE
0.0 SELECTED DRUM DIMENSIONS 0.180 KO Drum Pump(s) Capacity 938,889 Does Second Pump Start at HLL?
Dual Entry
TRUE
TRUE
UNIT
VALUE
TRUE
ft³/hr
100.00
TRUE
No
TRUE
--
Keep Hitting F9 till all the Convergence Checks turns “True” 28
Features – Selecting Drum Dimensions Selected Variables Calculated Values 16
Vapor Density, ρV
lb/ft³
17
Volumetric Vapor Rate, Q V
ft³/hr
18
Liquid Holdup Capacity
ft³
19
Calculated Drum Diameter, D C
ft
20
Calculated Minimum Drum Length (T/T), L C
ft
21
Slop Height from Bottom, H SC
22
SELECTED DRUM DIMENSIONS 0.180 KO Drum Pump(s) Capacity
VALUE 12.47
--
No
micron
303
ft
8.00
18.84 Selected Drum Length (T/T), L S
ft
18.50
ft
0.99 Slop Height from Bottom, H SS
ft
1.00
Liquid Holdup Height from Bottom (NLL), H NC
ft
4.65 Liquid Holdup Ht (Normal Level), H NS
ft
4.69
23
High Liquid Level Height from Bottom, H LC
ft
4.65 High Liquid Level Height, H LS
ft
4.69
24
Liquid Dropout Velocity, V DC
ft/sec
2.35 Liquid Dropout Velocity, V DS
ft/sec
2.38
25
Liquid Dropout Time, T DC
sec
1.40 Liquid Dropout Time, T DS
sec
1.39
26
Vapor Space Height, H VC
ft
3.29 Vapor Space Height, H VS
ft
3.31
27
Vapor Space Cross Sectional Area, A VC
ft²
19.3 Vapor Space Cross Sectional Area, A VS
ft²
19.6
28
Vapor Velocity, V VC
ft/sec
13.48 Vapor Velocity, V VS
ft/sec
13.29
29
--
5,025 C ( Re ) 2 1.298 Drag Coefficient, C S
--
5,180
30
C ( Re ) 2 Drag Coefficient, C C
--
1.284
31
Convergence Absolute Tolerance
ft
--
3.00
--
938,889 Does Second Pump Start at HLL?
UNIT gpm
500.0 Droplet Size for Selected Dimensions, d S 7.93 Selected Drum Diameter, D S
1.37E-10 Iteration Weight 29
Features – Liquid Levels ft
18.50 ft
0.00
ft
Inlet Nozzles Dia, in: 12.00 Outlet Nzzle Dia, in:
8.0 ft
14.00
Liq Levels From Bottom
( ft )
Section Vol
Residence Time, minute
HHLL (ESD)
0.00
( ft³ )
Incoming
Outgoing (2)
Note 3
HLL (2nd Pump Starts)
4.69
-566.8
-34.0
-340.1
-37.8
NLL (1st Pump Starts)
4.69
0.0
0.0
0.0
0.0
Add Holdup
Slop Level
1.00
500.0
30.0
300.0
33.3
Liq Holdup
LLL (Both Pumps Stop)
0.00
66.8
4.0
40.1
4.5
Slop Cap
0.0
0.0
0.0
0.0
Dead Vol
18.50 ft
Liq. Level LLL: Slop Level: NLL: HLL
Variable Fixed Free Free Free
HHLL: Vapor Space
Fixed Free
Definition Either the lower level tap or where pump(s) stop. Calculated based on slop volume. Calculated based on the holdup time (20-30 minutes) Calculated based on “Additional Holdup Volume”. Normally the second pump (if applicable) starts at this level. Emergency Shut Down (if effective). Calculated from HLL to the top of drum. 30
Vapor Space
Features – Section Vol., & Resid. Time ft
18.50 ft
0.00
ft
Inlet Nozzles Dia, in: 12.00 Outlet Nzzle Dia, in:
8.0 ft
14.00
Liq Levels From Bottom
( ft )
Section Vol
Residence Time, minute
HHLL (ESD)
0.00
( ft³ )
Incoming
Outgoing (2)
Note 3
HLL (2nd Pump Starts)
4.69
-566.8
-34.0
-340.1
-37.8
NLL (1st Pump Starts)
4.69
0.0
0.0
0.0
0.0
Add Holdup
Slop Level
1.00
500.0
30.0
300.0
33.3
Liq Holdup
LLL (Both Pumps Stop)
0.00
66.8
4.0
40.1
4.5
Slop Cap
0.0
0.0
0.0
0.0
Dead Vol
18.50 ft
Section Volumes: Incoming Resid Time: Outgoing Resid Time: Third Column (Note 3):
Volume between the two liquid levels. Based on incoming liquid flow rate. Based on capacity of one pump. Based on the balance of incoming liquid flow and outgoing pump-out rate by one pump. 31
Vapor Space
Features – Effective Drum Length Nozzle Centerline to Tangent 0.51
Nzzl. Centerline to Tan. ft
17.40 ft
0.59
Inlet Nozzle Dia, in:
Outlet Nzzle Dia, in:
12.00
8.0 ft
ft
14.00
Liq Levels From Bottom
( ft )
Section Vol
Residence Time, minute
HHLL (ESD)
0.00
( ft³ )
Incoming
Outgoing (2)
Note 3
HLL (2nd Pump Starts)
4.69
-566.8
-34.0
-340.1
-37.8
NLL (1st Pump Starts)
4.69
0.0
0.0
0.0
0.0
Add Holdup
Slop Level
1.00
500.0
30.0
300.0
33.3
Liq Holdup
LLL (Both Pumps Stop)
0.00
66.8
4.0
40.1
4.5
Slop Cap
0.0
0.0
0.0
0.0
Dead Vol
Vapor Space
18.50 ft
● ●
Effective Length of the drum is between inlet and outlet nozzle centerlines. The distance from the nozzle centerline to head seam must be greater than half of the nozzle diameter.
32
Features – Cell Comments
33
Questions and Discussions
34
