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Toxic QRAs 05/09/2023
R.A. Hawrelak (PERCS Inc. 519-542-8832)
Fig. 1: Logic Diagram For Toxic Mini-QRA
Start atTab QRA
Tab QRA Tab VM Tab VMSelect Select Vulnerability Model Obtain 4Toxic Chemical (1 - 20) 1 = CPQRA LC50 Concentrations4 Scenario Descriptions 2 = TNO4 Release Durations 3 = Specific Rat Data4 Generic Failure Rates 4 = Manual Input of k1, k2 & nAuto Sort Fatality DataDetermine IR DataDetermine Societal Risk
Tab FR Tab IRSelect Failure Plot Individual Risk to 1E-06 and 1E-08 Fatalities/YrRates For 4Generic Systems
Tab SRPlot Societal Risk vs Dutch QRA Criteria
Tab PPSelect PhysicalProperties
Tabs S1 - S9Select Source Term Models - Delivers Rate Of Discharge and Release Durations
S1 = 2 Liquid and 2 Vapour Orifice Calculations - Sonic & Sub-Sonic FlowS2 = Source Term Model - 2 Liquid and 2 Vapour Models + LogisticsS3 = Evaporation Rate From Un-Restrained Pool Spreading - Transient ReleaseS4 = Evaporation Rate From Restrained Pool Spreading - Transient releaseS5 = Evaporation Rate From Volatile Liquid Below Boiling Point - Steady State ReleaseS6 = Depressurization of a Pressurized Vessel - Transient ReleaseS7 = Release From PSV of a Vessel Containing Toxic Liquid Under Fire or Reactive Chemical ConditionsS8 = A Generalized Correlation for Flashing Choked Flow of Initially Subcooled LiquidS9 = Release of Heavy Toxic gases From Elevated Stacks or PSVs.
Tabs GC & GISelect Dispersion Model - Yields LC50 Distances & Durations For 4 Selected Scenarios
GC = Continuous Gaussian Model + Vulnerability DataGI = Instantaneous Gaussian Model + Vulnerability Data
Toxic QRAs 05/09/2023
R.A. Hawrelak (PERCS Inc. 519-542-8832)
LC50 Concentrations
Release From PSV of a Vessel Containing Toxic Liquid Under Fire or Reactive Chemical Conditions
Mini QRA For MIC Storage 05/09/2023
R.A. Hawrelak 01:46:57
Basis MIC Plant Under Poor Safety Management System (CPQRA Vulnerability Model)
Release and Dispersion Summary Based on a Continuous Gaussian Dispersion Model, CPQRA Vulnerability Probit Constants and Selected Source Term Models
BHOPAL - Incidents From One 90,000 lb Storage Tank Select (1 - 20) = 4Select Model (1 - 2) 1
Scenario Dischg Rate Duration LC50 Gaussian Source Source TermIncident Description kgm - kgm/s Minutes ppmv LC50 Dist, m Term Tab Description
1 2" Liq Leak 15.4353 60 39.86 2,172 Tab S4 Into 1,000 sm Dyked Area2 1/2" Liq Leak 1.54 60 39.86 545 Tab S4 Into 100 sm Restricted Curb Area3 Runaway Rx 3.6936 100 18.23 1,869 Tab S7 & S9 PSV to 8 Inch Ø Stack 108' High4 Tank Rupture 30.8739 85 23.38 4,355 Tab S3 Into 1,670 sm Unrestricted Area
Failure Frequency For System Components
Incident No. 1 - Generic System For 2" Liq Leak
Failure Rate Generic System For Phase Of No. In Frequency SourceNo. Incident 1 2" Liq Leak Leak Events/yr System Failure/Yr Fr FR database34 Valve or Flange Leak Vap or Liq 1.00E-04 10 1.00E-03 Technica35 Impact Failure Of Pipe Vap or Liq 1.00E-05 1 1.00E-05 CPQRA54 Med Pipe Rupt >2" <6" / m Vap or Liq 2.60E-07 1 2.60E-07 CPQRA, P-45948 Leak Errosion / Mech Stress Vap or Liq 1.35E-05 1 1.35E-05 Technica
Total 1.02E-03
Incident No. 2 - Generic System For 1/2" Liq Leak
Failure Rate Generic System For Phase Of No. In Frequency SourceNo. Incident 2 1/2" Liq Leak Leak Events/yr System Failure/Yr34 Valve or Flange Leak Vap or Liq 1.00E-04 10 1.00E-03 Technica39 Pump Seal Leakage Liquid 6.60E-04 1 6.60E-04 Technica22 Pipe Splits - 1/2 Inch Liquid 4.00E-04 1 4.00E-04 Nussey HSE36 PSV Leakage at Norm Press Vap or Liq 1.00E-04 1 1.00E-04 CPQRA99 0 0.00E+00
Total 2.16E-03
Incident No. 3 - Generic System For Runaway Rx See FT Tab For Details
Failure Rate Generic System For Phase Of No. In Frequency SourceNo. Incident 3 Runaway Rx Leak Events/yr System Failure/Yr
MIC Flows To Atm Fr Top VGS Vapor 4.00E-07 Fault Tree (FT)
Incident No. 4 - Generic System For Tank Rupture
Failure Rate Generic System For Phase Of No. In Frequency SourceNo. Incident 4 Tank Rupture Leak Events/yr System Failure/Yr48 Leak Errosion / Mech Stress Vap or Liq 1.35E-05 1 1.35E-05 Technica99 1 0.00E+0099 1 0.00E+0099 1 0.00E+0099 0 0.00E+00
Total 1.35E-05
Summary Of Representative Frequency Estimates BHOPAL - Incidents From OneManually Det'd
Incident Description Frequency/Yr Frequency Basis Source Gaussian Dist, m BM + Gauss, m1 2" Liq Leak 1.02E-03 Generic System see above 2,172 2,4052 1/2" Liq Leak 2.16E-03 Generic System see above 545 5313 Runaway Rx 4.00E-07 Fault Tree see below 1,869 1,9114 Tank Rupture 1.35E-05 Generic System see above 4,355 4,777
Mini QRA For MIC Storage 05/09/2023
R.A. Hawrelak 01:46:57
Based on a Continuous Gaussian Dispersion Model, CPQRA Vulnerability Probit Constants and Selected Source Term Models
Chemical = MICGaussian Dispersion
FrequencyFailure/Yr
Into 1,000 sm Dyked Area 1.02E-03Into 100 sm Restricted Curb Area 2.16E-03PSV to 8 Inch Ø Stack 108' High 4.00E-07Into 1,670 sm Unrestricted Area 1.35E-05
..
Toxic Chemical Vulnerability Model 05/09/2023
R.A. Hawrelak 01:46:57
Case Vulnerability Model (VM) Basis = CPQRA Probits
Toxic Basis 1 (1 = CPQRA, 2 = TNO, 3 = Rat Data, 4 = Manual Input k1, k2, & n)Select 1 to 20 4 MIC STEL 15 min. = ? ppmv CPQRA ProbitsTime = 100 minutes Pr = k1 + (k2)[LN(Dose)] = 4.9999Avg Conc'n = 18.23 ppmv 6.66E+02Avg Conc'n = 42.52 mgm/m3 @ t = 25.00 °C n = 0.6530% Fatality = 50.16% 51.78% 49.97% k1 = -5.6420Risk Message Fatality Potential Dose k2 = 1.6370
MW = 57.1
Fatality = IDLH LC1 LC10 LC50 LC90Probit = 1.6462 2.67 3.72 5 6.28
Minutes Avg ppmv Avg ppmv Avg ppmv Avg ppmv Avg ppmv1 914.16 2,382.19 6,361.61 21,066.96 69,764.872 316.25 824.10 2,200.76 7,287.97 24,134.675 77.74 202.57 540.96 1,791.45 5,932.5110 26.89 70.08 187.14 619.74 2,052.3160 1.73 4.51 12.04 39.86 132.0085 1.01 2.64 7.06 23.38 77.43
100 0.79 2.06 5.51 18.23 60.37
Lethal Toxicity Chart For MIC CPQRA Probits (Page down)
Dose =S(C^n)(t)=
1 10 1000.10
1.00
10.00
100.00
1,000.00
10,000.00
100,000.00
1,000,000.00
FATALITY CHART FOR SELECTED CHEMICAL
LC01LC10LC50LC90LC99IDLHData Pt.ERPG2ERPG3
EXPOSURE DURATION, MINUTES
AVG
PPMV
eg, LC50 = 50% Fatality
Toxic Chemical Vulnerability Model 05/09/2023
R.A. Hawrelak 01:46:57
ppmv - min.
LC99.98.09
Avg ppmv379,313.68131,220.9332,255.2411,158.48
717.71421.02328.26
1 10 1000.10
1.00
10.00
100.00
1,000.00
10,000.00
100,000.00
1,000,000.00
FATALITY CHART FOR SELECTED CHEMICAL
LC01LC10LC50LC90LC99IDLHData Pt.ERPG2ERPG3
EXPOSURE DURATION, MINUTES
AVG
PPMV
eg, LC50 = 50% Fatality
Failure Rates For Database LOOKUP
Failure RateNo. Description Phase Per Year Source1 Instantaneous Vessel Rupture Liquid 1.00E-06 Nussey HSE2 Instantaneous Vessel Rupture Vapor 1.00E-06 Nussey HSE3 Vessel Leakage Liquid 2.40E-05 Nussey HSE4 Vessel Leakage Vapor 3.60E-05 Nussey HSE5 Catastrophic Dist'n Tower Vap or Liq 6.50E-06 CPQRA, p-4596 Serious Dist'n Tower Leak Vap or Liq 1.00E-05 CPQRA, p-4597 2 Inch Hole In Pipe Liquid 1.60E-06 Nussey HSE8 1 Inch Hole In Pipe Liquid 3.20E-06 Nussey HSE9 1/2 Inch Hole In Pipe Liquid 4.00E-06 Nussey HSE
10 1/4 Inch Hole In Pipe Liquid 1.60E-05 Nussey HSE11 2 Inch Hole In Pipe Vapor 2.40E-06 Nussey HSE12 1 Inch Hole In Pipe Vapor 4.80E-06 Nussey HSE13 1/2 Inch Hole In Pipe Vapor 6.00E-06 Nussey HSE14 1/4 Inch Hole In Pipe Vapor 2.40E-05 Nussey HSE15 Gillotine 1 Inch Liquid 1.20E-07 Nussey HSE16 Gillotine 1/2 Inch Liquid 4.00E-05 Nussey HSE17 Gillotine 1/4 Inch Liquid 1.60E-04 Nussey HSE18 Gillotine 1 Inch Vapor 1.80E-07 Nussey HSE19 Gillotine 1/2 Inch Vapor 6.00E-05 Nussey HSE20 Gillotine 1/4 Inch Vapor 2.40E-04 Nussey HSE21 Pipe Splits - 1 Inch Liquid 1.20E-06 Nussey HSE22 Pipe Splits - 1/2 Inch Liquid 4.00E-04 Nussey HSE23 Pipe Splits - /4 Inch Liquid 1.60E-03 Nussey HSE24 Pipe Splits - 1 Inch Vapor 1.80E-06 Nussey HSE25 Pipe Splits - 1/2 Inch Vapor 6.00E-04 Nussey HSE26 Pipe Splits - 1/4 Inch Vapor 2.40E-03 Nussey HSE27 Gasket (3mm thk) 1/4 Dia Liquid 2.00E-06 Nussey HSE28 Gasket (3mm thk) 1/4 Dia Vapor 3.00E-06 Nussey HSE29 Gasket (1.6mm thk) 1/4 Dia Liquid 1.20E-06 Nussey HSE30 Gasket (1.6mm thk) 1/4 Dia Vapor 1.80E-06 Nussey HSE31 Tanker Cplg Transfer Hose Liquid 1.20E-06 Nussey HSE32 Tanker Cplg Transfer Hose Vapor 1.80E-06 Nussey HSE33 Tanker Cplg Transfer Hose Liquid 5.00E-04 CPQRA34 Valve or Flange Leak Vap or Liq 1.00E-04 Technica35 Impact Failure Of Pipe Vap or Liq 1.00E-05 CPQRA36 PSV Leakage at Norm Press Vap or Liq 1.00E-04 CPQRA37 PSV Under Fire Vap or Liq 3.00E-06 CPQRA38 Pump Case Rupture Liquid 6.60E-05 Technica39 Pump Seal Leakage Liquid 6.60E-04 Technica40 Compressor Seal Leakage Vapor 9.20E-06 Technica41 Compressor Case Rupture Vapor 9.20E-05 Technica42 Filter Vessel Rupture Vap or Liq 1.30E-05 Technica43 Filter Seal or Flange Leakage Vap or Liq 9.70E-04 Technica44 Adjacent Line Jet Fire Vap or Liq 5.00E-06 Technica45 Crane Impact on Transf Line Vap or Liq 4.40E-05 Technica46 Nozzle Leak Vap or Liq 6.00E-07 Technica47 Complete Nipple Screw Fail Vap or Liq 5.00E-03 Technica48 Leak Errosion / Mech Stress Vap or Liq 1.35E-05 Technica
49 Pipe Rup Along Transfer Line Vap or Liq 6.70E-05 Technica50 Coll'n Vehicle to Pipe support Vap or Liq 4.40E-06 Technica51 Sight Glass failure Vap or Liq 4.50E-02 Technica52 Small Pipe Rupt <=1" / meter Vap or Liq 8.80E-07 CPQRA, P-45953 Small Pipe Leak <=1" / meter Vap or Liq 8.80E-06 CPQRA, P-45954 Med Pipe Rupt >2" <6" / m Vap or Liq 2.60E-07 CPQRA, P-45955 Med Pipe Leak >2" <6" / m Vap or Liq 5.30E-06 CPQRA, P-45956 Large Pipe Rupt > 6" / meter Vap or Liq 8.80E-08 CPQRA, P-45957 Large Pipe Leak > 6" / meter Vap or Liq 2.60E-06 CPQRA, P-45958 Brittle Vessel Failure Vap or Liq 6.30E-04 ADL - FT596061626364656667686970
Case = Estimate the Frequency of Leaks and Catastrophic Rupture For An LPG Storage Sphere
95% Confidence Limits Of Failure Rate Data - For PV Catastrophic Rupture Failure
Basis: CPQRA, Page 351 See allso V.C. Marshall, Major Chemical Hazards, P-71
Upper Confidence Limit Lower Confidence Limit f1 = 2(x + 1) Eqn 5.5.22 f3 = 2(2 - x + 1) f2 = 2(n - x) Eqn 5.5.23 f4 = 2(x)
Where x = number of observations of failuren = sample size, vessel years
Upper Confidence Limit = (x + 1)F1 / [(n-x) + (x + 1)F1] Eqn 5.5.21
Lower Limit of Confidence = x / [(n-x + 1)F2 + x] Eqn 5.5.24
Where F1 and F2 = value of F-distribution with degrees of freedom f1 and f2 Typically, 95% confidence level is used.
Example: Data Of Smith and Warwick, 1983, CPQRA, page 358
20,000 pressure vessels with an exposure of n = 310,000This includes pipe failures and vessel failures.
Item Failures Table 4: F11 PV Catastrophic Rupture Failure 2 2.12 Catastrophic Pipework Failure 10 1.553 Pipe Work Leaks 34 1.304 Vessel Leaks 42 1.285 1 - 2 Inch Leak Size Failures 25 1.356 2 - 6 Inch leak Size Failures 153 1.00
Select 1 to 4 1 Observed Failures, x =
PV Catastrophic Rupture Failure / vessel yr = 6.45E-06 /vessel yr = x / n
Upper Confidence limit, f1 = 6 Eqn 5.5.22f2 = 619996 Eqn 5.5.23
From Table VII of Hald (1952a) for P = 0.95, F1 = 2.10
Eqn 5.5.21 Upper Confidence Limit = 20.32E-06 PV Catastrophic Rupture Failure / vessel-yrs
For 8,760 hours per years
Failure per 1E06 Hours = 2.32E-03
Lower Confidence Limit, f3 = 619998 Eqn 5.5.25f4 = 4 Eqn 5.5.26
From Table VII of Hald (1952a) for P = 0.95, F2 = 5.63
Eqn 5.5.24 Lower Confidence Limit = 1.15E-06 PV Catastrophic Rupture Failure / vessel-yrs
Failure per 1E06 Hours = 1.31E-04 PERD Lower =
The analyst can be 95% certain the value for PV Catastrophic Rupture Failure
falls in the range Lower Limit = 1.15E-06 to Upper L =failures per vessel year
Index = 1.00
PV Catastrophic Rupture Failure / vessel yr = 1.15E-06 6.45E-06
Failure Rate Within 95% Confidence Limits 1.00 5.63
Estimate the Frequency of Leaks and Catastrophic Rupture For An LPG Storage Sphere
PV Catastrophic Rupture Failure Slope m Constant bHole In Pipe - Liq Phase -1.028771 -12.31858
See allso V.C. Marshall, Major Chemical Hazards, P-71 Inch Fail/Yr Inch Fail/Yr2.00 2.40E-06 2 2.19E-061.00 4.80E-06 1 4.468E-06
Eqn 5.5.25 0.50 6.00E-06 0.50 9.12E-06Eqn 5.5.26 0.25 2.40E-05 0.25 1.86E-05
with f1 and f2
with f3 and f4
vessel years = n
Table 4: F25.631.841.371.331.451.00
2
/vessel yr = x / n
f1 = 2(x + 1) f2 = 2(n - x)
Table 4, p-258
PV Catastrophic Rupture Failure / vessel-yrs
f3 = 2(2 - x + 1)f4 = 2(x)
Table 4, p-258
0.1 1 100.000001
0.00001
0.0001
Column OColumn Q
PV Catastrophic Rupture Failure / vessel-yrs
PERD page =
PV Catastrophic Rupture Failure
2.03E-05
17.73
2.03E-05
17.73
Constant b Slope m Constant bHole In Pipe - Liq Phase -1.028771 -12.72405Inch Fail/Yr Inch Fail/Yr
2 1.60E-06 2 1.46E-061 3.20E-06 1 2.979E-06
0.5 4.00E-06 0.5 6.077E-060.25 1.60E-05 0.25 1.24E-05
Slope m Constant bHole In Pipe - Vapor Phase -1.028771 -12.31858Inch Fail/Yr Inch Fail/Yr
2.00 2.40E-06 2 2.19E-061.00 4.80E-06 1 4.468E-060.50 6.00E-06 0.50 9.12E-060.25 2.40E-05 0.25 1.86E-05
0.1 1 100.000001
0.00001
0.0001
Column OColumn Q
Incident No. 3 - Estimated Fault Tree Analysis For BHOPAL Event - Poor Safety Management System
MIC Flows To Atm Fr Top VGS
E6 = E5*P5 = 4.00E-07 per Yr
And
MIC Flows To Flare Stack Flare Stack Not Available Due ToLine Maintenance
E5 =P4*E4 = 4.00E-06 per Yr P5 = 0.1
And
VGS Pump Fails to Start MIC Flows To Off Line VGS VGS On Standby
Est'd P4 = 0.01 E4 = E3*P3 = 4.00E-04 per Yr
And
Tank At Amb Temp & Runaway Operator Does Not ControlReaction Starts Very Fast Runaway
E3=E1+E2 = 2.00E-03 per Yr P3=P1+P2 = 0.20
Or Or
Water Fr N2 Header Water Enters By Sabotage Inst Alarms & Oprs Do Not Operators Fail To Notice AlarmsOperator error Disgruntled Employee Respond. Incorrect Set Pt. Runaway Takes Off
E1/Yr = 1.00E-03 E2/Yr = 1.00E-03 Prob P1= 0.10 Prob P2=
Operators Fail To Notice AlarmsRunaway Takes Off
0.10
IR
Page 16
0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,0001.00E-08
1.00E-07
1.00E-06
1.00E-05
1.00E-04
1.00E-03
Individual Risk
Data Pts.Best Fit
Distance, Meters
Accu
mul
ated
Ris
k Pe
r Yea
r
Societal F_N Curve 05/09/2023
R.A. Hawrelak 01:46:57
1 10 100 1000 100001.00E-07
1.00E-06
1.00E-05
1.00E-04
1.00E-03
1.00E-02
Societal F-N Curve For MIC Storage Area
AcceptableUnacceptableCase Study
No. Fatalities, N
Freq Of N or More Fatali-
ties/Yr
Unacceptable
Mitig'n
Reqd
Acceptable
Dutch Criteria For Acceptable To Unacceptable - BM - HSE Escape Model
Physical Properties
Chemical = MIC
Vessel Pressure at Failure =. 7.02 barg Press, P =Vessel Temp. at Failure, T = 115.56 °C T =Atm Boiling Point, Tnb = 38.89 °C Tnb =Mol Wt. = 57.1 Atm Press. =UEL, vol % = % Relative Humidity, RH =LEL, vol % = %Heat Of Combustion, HC = 4.4.E+05 J/kgm HC =Spec Heat Ratio, Cp/Cv = 1.146 Ideal Gas Cp-Cv = 2 Cp =Liquid Density @ atm bp = 977.10 kgm.cu.m. DL =Latent Ht @ atm bp, L = 4.03E+05 J/kgm L =Liq Heat Capacity, CpL = 1,800 J/kgm/°K CpL =Vapor Pressure, vp = 7.02 barg Vapor Pressure, vp =Ambient Temperature = 293.00 °K 68.00 °FLiquid Head, hL = 6.10 meters hL =
TNT Equivalent Heat Of Combustion, 4.65E+06 J/kgm TNT HC =Vessel Failure During = PSV Flow See Tab S7Special Conditions = Nitrogen Pad Lost
Basis Engineering Data Book - Natural Gas Process Suppliers Association - 9th Edition - 1972 - Chapter 16
Antoinne Constants Not added to PP yetvp, psi =10^(A+B/(°C+C))
116.35 psia °C = 115.56240 °F A = 5.01922143102 °F B = -976.81162
14.696 psia C = 215.178550.00% Default = 50%
189 BTU/lb15.71 BTU/lb mole/°F
61 lb/cf173.3 BTU/lb0.43 BTU/lb/°F
116.35 psia20.00 °C
20 ft.2,000 BTU/lb (Default = 2,000)
Engineering Data Book - Natural Gas Process Suppliers Association - 9th Edition - 1972 - Chapter 16
Screen 4 Calculation of Source Terms (See Tab PID for Typical Credible Scenarios)
Liquid Leaks For Vessel Holes, Full Bore and Partial Pipe Diameter BreaksBasis = Eqn 2.1.7 CPQRA, P449Scenario = 1 2" Liq Leak Scenario = 2
Dia. = 0.0508 meters Dia. = 0.0127Area = 0.0020 sq.m. Area = 0.00013GL = 47.67 kg/sec GL = 2.98Drain Time = 14.27 minutes Drain Time= 228.35Type = Long Term - Continuous Type = Long Term - Continuous
Determine % Flash If Flash is less than 10%, assume rainout will occur and special pool dispersion is
Frac Flashed = 1-EXP(-CpL*(T - Tnb) / L) = 28.99% > 10%, Assume No Rainout for Any Liquid Releases & Assume 100% vapor
Vapor Leaks For vessel Holes, Full Bore and Partial Pipe Diameter Breaks Basis = Eqn 2.1.1 Page 450 CPQRAScenario 3 = 2 Inch Vapor leak Case = 25% Dia., m
Dia. = 0.0508 meters Dia = 0.0127Area = 0.00203 sq.m. Area = 0.000127Critical Ratio = 1.74 Crit Ratio = 1.74DP Ratio = 8.02 DP Ratio = 8.02Is Flow Sonic? Sonic Is Flow Sonic? SonicFlow factor = 0.68 Flow factor 0.68Alpha 221.04 Alpha = 221.04GV for 2 Vapor Lines = 10.05 kg/s Gv = 0.63Frac Flashed as above = 28.99% Frac Flshd= 28.99%Flash Vapor wo Entrain't = 26,095 kgms Q wo Ent = 26,095Time to Depressure = 43.29 minutes Time to Dep 692.65Type For 1 Lines = Long Term - Continuous Type = Long Term - Continuous
(See Tab PID for Typical Credible Scenarios)
1/2" Liq Leakmeters 0.50 Inchsq.m.kg/sec Noteminutes
Long Term - Continuous
If Flash is less than 10%, assume rainout will occur and special pool dispersion is ( Note)
> 10%, Assume No Rainout for Any Liquid Releases & Assume 100% vapor
To be checked out
25% Dia., mmeters 0.50 Inchsq.m.
kg/sec Note
kgms Assumes constant flash vapor rate.minutes
Long Term - Continuous
Representative Set Of Source Terms 05/09/2023
R.A. Hawrelak 01:46:57
Turbulent Free JetsNew TNO Yellow Book, Chapter 3Example , Part 6, Page 22 Turbulent Free Jet
Data Chemical MIC Outflow = UpwardsMW = 57.1Cp/Cv = 1.30 ideal gas where Cp-Cv = 2Ves Press = 72.1 psia 497,057.40 pascals 4.97 bar absAtm Press = 14.7 psia 101,341.80 pascals 1.01 bar absAmb Temp = 77 °F 298.20 °KHole Dia = 2.00 inches 5.08 cm Hole area, Ao 0.002026879 sq.m.Flow Coeff = 0.60Viscosity = 0.0083 centipoiseLEL = 2.10%UEL = 9.50%
Test For Sonic Flow W 15,363 lb/hrMW Air = 28.84 21% O2Pr/Pa = 4.90 [Pr/Pa]^(1/k)= 3.40Crit Ratio = 1.83Note Pr/Pa > Crit Press Ratio - Sonic Flow
TNO Initial Flow Rate, mo = 1.94 kg/secAmbient Air density = 1.18 kg/m3Gas Density In Vessel, Dg,r = 11.44 kgm/m3Gas expansion factor = 0.63Gas Density at Opening, Dg,o 7.18 kgm/m3Gas Velocity at Opening, Uo = 221.61 m/s
Test For turbulence - Re No. greater than 2.5E+04
Re No. = 7.54E+06 Re > 25000 - Turbulent Flow - Eqns apply.
Gas Dens After Expan'n, Do,e 3.37 kgm/m3
Equivalent Dia., deq = 0.0575 meters 2.26 inches
b1 = 106.93 Eqn (6), p-12, Constant for the velocity distribution
b2 = 104.18 Eqn (7), p-12, Constant for the concentration distribution.
(b1+b2)/b1= 1.97
Density of Gas relative to air 1.98 Relative Density Outside 0.14 to 1.53 Limits - Extrapolations Are ApproximateRela gas density after exp = 2.86 Eqn 8, p-130.32 denominator term = 0.37
Eqn 14, p-14 At LEL, jm = 2.10% x/deq = 253.46 x LEL = 14.56 metersEqn 14, p-14 At UEL, jm = 9.50% x/deq = 58.06 x UEL = 3.34 meters
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
-0.80-0.60-0.40-0.200.000.200.400.600.80
Concentration Profile in the Free jet
LELLELUELUEL
Jet length, Meters
Jet
Wid
th, M
eter
s
Representative Set Of Source Terms 05/09/2023
R.A. Hawrelak 01:46:58
Calculation Of Jet Footprint at LEL 7.882240059x/deq Incs = 22.33
x/deq Conc'n, Jm y/deq x, meters y, meters -y,meters b3 x"253.46 2.10% 0.00 14.56 0.00 0.00 0 #DIV/0!231.13 2.31% 6.91 13.28 0.40 -0.40 0.029912596 13.28206633208.81 2.55% 9.06 12.00 0.52 -0.52 0.043377232 11.99915503186.48 2.86% 10.18 10.72 0.59 -0.59 0.054604034 10.71624373164.16 3.26% 10.67 9.43 0.61 -0.61 0.064993743 9.433332438141.83 3.78% 10.66 8.15 0.61 -0.61 0.075178988 8.150421142119.51 4.51% 10.23 6.87 0.59 -0.59 0.085613378 6.86750984697.18 5.57% 9.40 5.58 0.54 -0.54 0.096768317 5.58459854974.86 7.29% 8.18 4.30 0.47 -0.47 0.109311584 4.30168725352.53 10.55% 6.54 3.02 0.38 -0.38 0.124488624 3.01877595730.21 19.09% 4.40 1.74 0.25 -0.25 0.145561164 1.735864667.88 100.00% 1.52 0.45 0.09 -0.09 0.192571826 0.452953364
Calculation Of Jet Footprint at UEL 7.882240059x/deq Incs = 4.56
x/deq Conc'n, Jm y/deq x, meters y, meters -y,meters58.06 9.50% 0.00 3.34 0.00 053.50 10.35% 1.54 3.07 0.09 -0.0948.94 11.37% 2.03 2.81 0.12 -0.1244.38 12.61% 2.31 2.55 0.13 -0.1339.82 14.16% 2.46 2.29 0.14 -0.1435.25 16.14% 2.51 2.03 0.14 -0.1430.69 18.76% 2.48 1.76 0.14 -0.1426.13 22.40% 2.37 1.50 0.14 -0.1421.57 27.79% 2.19 1.24 0.13 -0.1317.01 36.60% 1.94 0.98 0.11 -0.1112.44 53.59% 1.60 0.72 0.09 -0.097.88 100.00% 1.18 0.45 0.07 -0.07
Calculation Of Volume Of Gas Between UEL and LEL by Eqn 19, p-16
1 to LEL 0.021 0.0225 0.025 0.0275 0.03 0.035 0.04 0.045
(a) = š/3/b2 = 0.0100522488 0.010052249 0.010052249 0.010052249 0.010052249 0.010052249 0.010052249 0.010052249(b) = 2nd term = 0.003604627 0.003604627 0.003604627 0.003604627 0.003604627 0.003604627 0.003604627 0.003604627
(a)(b) = 3.623461E-05 3.62346E-05 3.62346E-05 3.62346E-05 3.62346E-05 3.62346E-05 3.62346E-05 3.62346E-05(c) = 3rd term = 3.847577893 3.847577893 3.847577893 3.847577893 3.847577893 3.847577893 3.847577893 3.847577893(d) = 1/jh^2-1 2266.5736961 1974.308642 1599 1321.31405 1110.111111 815.3265306 624 492.8271605(e) = (c)(d) = 8720.8188461 7596.306285 6152.277051 5083.858727 4271.23897 3137.032335 2400.888605 1896.190888(f) = 4th term = -534.1622151 -497.787532 -446.862977 -405.197431 -370.476143 -315.914119 -274.992601 -243.164754(g) = 5th term = 21.970085521 21.5777252 20.97854321 20.43651717 19.94168616 19.06503602 18.30564712 17.63581865(h) = 6th term = 0.9211140276 0.919702719 0.917350538 0.914998357 0.912646176 0.907941815 0.903237453 0.898533091
(e) - (f) + (g) + (h) = (i) = 9277.8722607 8116.591245 6621.035921 5510.407673 4662.569445 3472.919432 2695.090091 2157.889993
(i)(a)(b)=Vg,Gas Vol, Eq19= 0.3362 0.2941 0.2399 0.1997 0.1689 0.1258 0.0977 0.0782
Vgas 1-2 0.04 0.05 0.04 0.03 0.04 0.03 0.02 0.01Vgas/javg 1.93 2.28 1.53 1.07 1.33 0.75 0.46 0.30Sum (V/j) 10.34 m3 total volume of gas By Simple Inc'ts, Vol. Gas = 10.07 m3Avg Conc = 3.06% Vol %V total 0.32 m3 incremental Volume Of FlammableV total 0.32 m3 Vol LEl - Vol UEL
>>> lbs In Flam = 1.07 kgms 2.35 lbs
Gravity Effects (Page 24) Flow is Upwards
Eta = 2.21 p-24Fr = 1.34E+05 p-24Io = 428.97 p-24Xc = 46.50 meters Culmination Height p-24X LEL = 14.56 meters LEL Ht wo Gravity EffectsXc/XLEL = 3.19 Xc/XLEL >= 1.5 - Culmination Cloud Is Not Explosive.
Based On Calm Weather
If there is wind, the suitability of the calculation method is determined by thevelocity of outflow and the ut / Uo ratio. See Introduction Re17 and on.
Methodology For Evaporation From Unrestricted Spill 05/09/2023
R.A. Hawrelak 01:46:58
Summary Table, Evaporation of Refrigerated MIC
CASE 1: BHOPAL - Incident No. 4 - Loss Of Refrigerated MIC
Unrestrained Circular Pool On Average Soil Surface is PenetrableTotal Spill 40,824 kgms Pool Ht, mm 25 Rough Sand or GravelFlash Liq 40,824 kgms From Pool of Area = 1,670.37 sq. m.Flash Vap 0 kgms During First Minute of SpillWind 11.18 mph Atmospheric Stability = Neutral ConditionsGround at 21.11 deg C
SEE TABLE 4, Page 7 Incremental Total Ground Incremental Total TotalWind Ground Conduction MIC MIC MIC
Convection Conduction From Maxim Lost To Lost To RemainingEvaporation Evaporation Pool Formed Atmosphere Atmosphere In Spill Area
Time Fr, sec Time to, sec kgm. kgm. kgm. kgm. kgm kgm.0.00 16.47 0.00 898.01 0.00 898.01 898.01 39,925.9916.47 60.00 138.77 2,188.94 2,188.94 2,327.71 3,225.72 37,598.2860.00 120.00 191.26 1,186.79 3,375.72 1,378.05 4,603.77 36,220.23
120.00 180.00 191.26 866.87 4,242.59 1,058.13 5,661.90 35,162.10180.00 240.00 191.26 717.62 4,960.21 908.88 6,570.78 34,253.22240.00 300.00 191.26 626.18 5,586.39 817.45 7,388.23 33,435.77300.00 360.00 191.26 562.74 6,149.13 754.01 8,142.23 32,681.77360.00 420.00 191.26 515.39 6,664.52 706.66 8,848.89 31,975.11420.00 480.00 191.26 478.30 7,142.82 669.57 9,518.46 31,305.54480.00 540.00 191.26 448.22 7,591.05 639.49 10,157.95 30,666.05540.00 600.00 191.26 423.19 8,014.24 614.46 10,772.41 30,051.59600.00 660.00 191.26 401.94 8,416.18 593.21 11,365.61 29,458.39660.00 720.00 191.26 383.60 8,799.78 574.87 11,940.48 28,883.52720.00 5,112.00 14,000.59 14,882.57 23,682.36 28,883.17 40,823.65 0.35
Time To Evaporate Spill = 85.20 Minutes Total Lost To Atm in Ist Min = 3,225.72 kgms.Total Lost To Atm in Ist Min = 7,111 lbs% Vaporzd in ist Minute = 7.90%
Initial rate = 3,225.72 kgm/min. 426,569 lb/hrAvg rate = 479.15 kgm/min. 63,363 lb/hr 1056.34 lb/min.Dispn rate = 1,852.44 kgm/min. 244,966 lb/hr 1/2 way between initial and avg rateDispn rate = 30.87 kgms/sec
Methodology For Major Spill Into Dyked Area 05/09/2023
R.A. Hawrelak 01:46:58
Summary Table, Evaporation of Refrigerated MIC
CASE BHOPAL - Scenario 1 - Leak Into 1,000 m2 Restricted Area
Bunded Circular Pool On Average Soil Surface is PenetrableTotal Spill 40,824 kgms Dyke Dia = 35.84 Tank Dia = 3Flash Liq 40,824 kgms From Pool of Area = 1,001.32 sq. m.Flash Vap 0 kgms During First Minute of SpillWind 11.18 mph Atmospheric Stability = Neutral ConditionsGround at 21.44 deg C
See Table 5, Page Incremental Total Ground Incremental TotalWind Ground Conduction MIC MIC
0.0166666667 Convection Conduction From Maxim Lost To Lost ToEvaporation Evaporation Pool Formed Atmosphere Atmosphere
Time fr, hour Time to, hour kgm. kgm. kgm. kgm. kgm0.00 0.0167 100.42 1,540.51 1,540.51 1,640.93 1,640.930.02 0.0333 100.42 638.10 2,178.62 738.52 2,379.450.03 0.0500 100.42 489.63 2,668.25 590.05 2,969.510.05 0.0667 100.42 412.78 3,081.03 513.20 3,482.710.07 0.0833 100.42 363.67 3,444.69 464.09 3,946.790.08 0.1000 100.42 328.78 3,773.47 429.20 4,375.990.10 0.1167 100.42 302.34 4,075.82 402.76 4,778.750.12 0.1333 100.42 281.41 4,357.23 381.83 5,160.590.13 0.1500 100.42 264.31 4,621.54 364.73 5,525.320.15 0.1667 100.42 249.99 4,871.53 350.41 5,875.730.17 0.1833 100.42 237.77 5,109.31 338.19 6,213.920.18 3.22 18,296.38 16,303.29 21,412.59 34,599.67 40,813.59
Time To Evaporate Spill = 3.22 Hours Total Lost To Atm in Ist Min = 1,640.93 Loss To Atm in 2nd Min. = 738.52
Initial Rate = a 1,640.93Avg Rate = b 211.30
Leak Rate and Source term Disp'n Rate = (a+b)/2 926.12Disp'n Rate = (a+b)/2 15.44
Initial Rate = a 3,617.60Avg Rate = b 465.84Disp'n Rate = (a+b)/2 2,041.72Disp'n Rate = (a+b)/2 122,503.31
Methodology For Major Spill Into Dyked Area 05/09/2023
R.A. Hawrelak 01:46:58
meters
TotalMIC
RemainingIn Spill Area
kgm.39,183.0738,444.5537,854.4937,341.2936,877.2136,448.0136,045.2535,663.4135,298.6834,948.2734,610.08
10.41
kgms.kgms
kgm/min.kgm/min.kgm/min.kgm/sec
lb/min.lb/min.lb/min.lb/hr
Methodology for Liquid Evaporation Rate - Non Boiling Liquids 05/09/2023
R.A. Hawrelak 01:46:58
CONVECTIVE EVAPORATION OF VOLATILE LIQUIDS FROM RECTANGULAR POOLSBasis: Lihou Course, p-4, Clancy V.J. Chem Proc Hazards, 1974, p-80, IChemE Symp. Ser. No. 39a
Liquid = Acrylonitrile U.S. EPA Example 4Vapor Mol Wt = 53.1 If multicomponent, evaporation rate may be unsteady stateLiq Temp, T = 77 deg F 298.00 deg K 25.00 deg CVP at T, Ps = 2.06 psia 0.1420 barPool width, y = 110.43 feet 33.66 meters Area, sf = 12195.00Pool Length, x = 110.43 feet 33.66 meters, (wind across this dimension)Wind Speed, U = 3.355 mph 1.50 meters/sec
Calculations per equations 9, Page 4
Satd Vap Density 0.018984 lb/cu. ft. 0.3041 kgm/cu. m RHOS = MW*VP/(10.73*°R)
Unstable Neutral Stablen factor 0.2 0.25 0.2K factor 0.001278 0.00157 0.001786
Rate, kgm/s = 0.44562 0.50161 0.62275 Eqn 9 No Conduction
Rate, kgm/min 26.74 30.10 37.36
Rate, lb/min = 58.94 66.35 82.37
Rate, lb/hr = 3,536.64 3,981.03 4,942.44
CONVECTIVE EVAPORATION OF VOLATILE LIQUIDS FROM CIRCULAR POOLSBasis: Clancy V.J. Chem Proc Hazards, 1974, p-80, IChemE Symp. Ser. No. 39a
Liquid = Acrylonitrile Example 2, Page 4, Lihou CourseVapor Mol Wt = 53.1 If multicomponent, evaporation rate may be unsteady stateLiq Temp, T = 77 deg F 298.00 deg K 25.00 deg CVP at T, Ps = 2.06 psia 0.1420 barPool Radius, r = 62.30 feet 18.99 meters Area, sf = 12,195.00Wind Speed, U = 3.355 mph 1.50 meters/sec
Calculations per equations 10, Page 4
Satd Vap Density 0.018984 lb/cu. ft. 0.3041 kgm/cu. m RHOS = MW*VP/(10.73*°R)
Unstable Neutral Stablen factor 0.2 0.25 0.2K' factor 0.003846 0.004685 0.005285
Rate, kgm/s = 0.44966 0.50775 0.61791 Eqn 10 No Conduction
Rate, kgm/min 26.98 30.46 37.07
Rate, lb/min. = 59.48 67.16 81.73
Rate, lb/hr = 3,568.76 4,029.73 4,904.03
Leak Rate = 4,904.03 lb/hr Stable ConditionsDuration = 4.08 hr 20,000 Lb Tank LoadDens = 50 lb/cfVol = 400.00 cfArea = 12,195 sfLiq Ht = 0.39 inches 1.00 cm
TIME TO DEPRESSURE A VESSEL WITH LIQUID AT ITS BOILING POINT 05/09/2023
R.A. Hawrelak 01:46:58
Case No. Chlorine 90 Ton Tank Car Example
Phys Properties of CHLORINE No Inert Gas Pad Starting Liq Temp = 77.00 °F Vessel Dia., ft 10 Starting Psia 112.90 Vap Press Tan-Tan L, ft 40 Final Psia 14.70 % Full 66.00% Number Incs 20 Vessel Vol., cf 3,142 89 Dp/Inc 4.91 Liq cf= 2,073 181,077 Number of Nozzles 1 Vapor cf 1,068 1,671 Flow Coeff Assumed = 1.0000 Conservative Nozzle Dia., inches 2.00 Cp/Cv = 1.36
Time Vapor Rate Vessel Press Flow Liq In Vessel Vapor Lost toMinutes lb/hr Psia Condition Lbs Atmos., lbs.
0.00 48,154 112.90 Sonic 181,077 01.46 46,091 107.99 Sonic 179,972 1,1453.04 44,045 103.08 Sonic 178,828 1,1874.76 41,997 98.17 Sonic 177,638 1,2346.64 39,947 93.26 Sonic 176,397 1,2868.71 37,897 88.35 Sonic 175,102 1,34311.00 35,844 83.44 Sonic 173,746 1,40513.54 33,789 78.53 Sonic 172,325 1,47316.36 31,732 73.62 Sonic 170,835 1,54519.53 29,671 68.71 Sonic 169,270 1,62123.10 27,608 63.80 Sonic 167,626 1,70327.14 25,541 58.89 Sonic 165,900 1,78831.73 23,471 53.98 Sonic 164,087 1,87737.00 21,396 49.07 Sonic 162,186 1,97043.09 19,317 44.16 Sonic 160,192 2,06650.20 17,233 39.25 Sonic 158,103 2,16558.60 15,143 34.34 Sonic 155,919 2,26568.67 13,048 29.43 Sonic 153,638 2,36781.07 10,844 24.52 Sub Sonic 151,259 2,46997.57 7,858 19.61 Sub Sonic 148,783 2,572
126.99 3,048 14.70 Sub Sonic 146,211 2,673
Overall Mass Balance Dispersion Modeling Of Transient Conditions
Initial Final Initial lb/hr = 48,154Lb in Liquid Ø = 181,077 146,211 Avg lb/hr = 17,082Lb in Vapor Ø = 1,671 383 Final lb/hr = 3,048
Lb Lost To Atm = 0 36,153Totals = 182,747 182,747 For Disp'n, lb/hr = 1/2(Init'l + Avg Rates)
% of Total Lost to Atm = 19.78% Disp'n, lb/hr= 32,618 Time to Vent to Atm Press = 126.99 min. Disp'n Time = 66.50
2.12 hr.
TIME TO DEPRESSURE A VESSEL WITH LIQUID AT ITS BOILING POINT 05/09/2023
R.A. Hawrelak 01:46:58
Flow
m3lbslbs
Accumulated lbs Vapor
01,1452,3313,5654,8516,1947,5999,072
10,61612,23813,94015,72817,60619,57621,64323,80726,07228,43930,90833,48036,153
Dispersion Modeling Of Transient Conditions
SonicSonic
Sub Sonic
For Disp'n, lb/hr = 1/2(Init'l + Avg Rates)
Sonicmin.
SIZING AND COST OF FARRIS PSV SYSTEMS 05/09/2023
R.A. HAWRELAK 01:46:58
PSV SIZING FOR FIRE CODITIONS
Chemical MIC PSV 109 V-11Mol Wt 57.1Method (1=NFPA,2=API-520) 1Orientation (1=H,2=V) 1 Horrizontal Vessel Fator for Wetted Area = 0.75Diameter 8 ft.Tan to Tan 40 ft.Max Liq Height 6 ft.Tot Vessel Area 1,125.95 sq. ftWetted Area = 844.46 sf to max 50 ft. if VerticalHeat Input, Q = 2,710,643 BTU/HrGas Constant 315 (If unknown, set = 315, See Area_Phys_Prop)Atmospheric Pressure = 14.7 psiaCredit Factor (1 to 5) 3 Insulation in accordance with 2-2.5.7 (generally only double steel walled)NFPA Protection factor = 0.3Operating Pressure = 14.7 psiaDesign pressure = 40 psigPSV Set Pressure = 75.4545455 psig Design = 40 psigPSV Flow factor For Fire = 1.21PSV Flow Pressure = 106 psia Set pressure adjusted so that Temp > 212F to boil cooling water applied to vesselPSV Flow Temp = 240 °F From Phys PropsLatent Heat at Flow Temp, L = 173.3 BTU/lb Fr Phys PropVapor Density at Flow Temp = 1.03 lb/cf Fr Phys PropIdeal Vap Den @ Flow Temp = 0.8058 lb/cfCompress Factor @ Flow Temp= 0.7824 Assume 1.0 if unknownFlow Factor For Max PSV Cap = 1.8741 Set at 1 for design. Adjust for max PSV flow capacity Vapor Flow = Q/L 29,314 lb/hr G = 3.6936 kgms/secBack Press < 55% flow Press ? 1 1 = yes, 2 = 0Vaiable or fixed?Kb, Back Press factor = 1 See Farris , p-3.06 Sizing SectionPSV Oficie Area Req'd 2.8530 Sq. inches Adjust till Area Req'd = Selected AreaSelect PSV Class = LSelected Orifice Area = 2.853 sq. in.Estimated Inlet Size = 3 inches (Check DP less 3% of set pressure to prevent chattering)Estimated Outlet Size = 4 inches (Check DP less 10% of set pressure to prevent chattering for conventional PSV type)
Note: to overcome chattering use a balanced bellows PSV
Orifice Selection Typical Inlet Typical Outlet Selection Size Size
Class Sq. in. Sq. in. Inches InchesD 0.110 1 2E 0.196 1 2F 0.307 1.5 2G 0.503 1.5 2.5H 0.785 1.5 3J 1.287 2 3K 1.838 3 4L 2.853 2.853 3 4M 3.600 3.6 4 6N 4.340 4.34 4 6P 6.380 6.38 4 6Q 11.050 11.05 6 8R 16.000 16 6 8T 26.000 26 8 10
SIZING AND COST OF FARRIS PSV SYSTEMS 05/09/2023
R.A. HAWRELAK 01:46:58
Set pressure adjusted so that Temp > 212F to boil cooling water applied to vessel
inches (Check DP less 10% of set pressure to prevent chattering for conventional PSV type)
Fauske Generalized Correlation For Flashing Choked Flow 05/09/2023
R.A. Hawrelak 01:46:58
A Generalized Correlation for Flashing Choked Flow of Initially Subcooled LiquidJ.C. Leung, M.A. Grolmes, Fauske & Associates, Inc., AICheE Journal, April 1988, Vol. 34, No. 4, P-688
Fauske Example, P-690
Initial Liq Temp, To = 512.06 °F 540 °KInitial Vessel Pressure, Po = 798 PSIA 5.50 MPaVapor Pressure at T, Ps = 760 PSIA 5.24 MPaLiquid Density, rfo = 48.26 lb/cf 773.00 kg/cu.m. vfo = 1/ rfo = 0.001294Vapor Density, rgo = 1.6794 lb/cf 26.90 kgm/cu.m. vgo = 1/rgo = 0.037175Liquid Latent Heat, hfgo = 697.72 btu/lb 1,622.90 kJ/kgLiquid Specific Heat, Cfo = 1.2035 btu/lb/°F 5,039.00 J/kg/°K
Omega, w = Cfo*To*Ps*((vfo-vgo)/hfgo)^2/vfo = 5.39 Eqn 5
ns = Ps / Po, by definition, the saturation pressure ratio = 0.9524
nct = (2*Omega-1)/(2*Omega) = 0.9072 Eqn 11
Is ns>=nct? If true, Eqn 10 can be used, = 1 Eqn 10 can be used
nc = ns*(1/nct)*(1-(1-nct/ns)^0.5) = 0.8211 Eqn 10
Gc* = nc / (Omega*ns)^0.5 = critical mass velocity = 0.3625 Eqn 9a,
Po in psia to kgm/sq.m.*g = psia*703*9.81 = Po' = 5.50E+06 (kgm/sq.m.)(m/sec^2)
Gc = (Gc*)(Po'*rfo)^0.5 1.74E+07 lb/hr/sf 23,644 kgm/sq.m./s by Eqn 9a and 9b
If, for example, the hole diameter is 1.0 inch, calculate the rate of two phase flow?
Orifice Dia = 1.00 inch 2.54E-02 meterOrifice Area = D^2/4 =� 5.45E-03 sf 5.07E-04 sq.m.2Ø Flow Rate = (Gc)(A) = 95,086.03 lb/hr 11.98 kgm/sec
This paper gives a generalized correlation for flashing choked flow of an initially subcooled liquid.The model assumptions are:
1. Piping resistance are not included, the release is from a hole in the vessel.2. Isentropic flow.3. Thermal equilibrium.4. Equal phase velocities once saturation is reached.
The model is a limiting case, without consideration of nonequilibrium effects.In this regard, it gives a lower-bound estimate for the mass flow rate and should be a useful tool for many engineering applications.
For Two Phase Flow With Piping Resistance, 1987 Boston Vapor Cloud Conference, p-257.
To account for piping resistance, Fauske determined a flow reduction factor, FR = 1.9454*(L/D equivalent)^-0.2091Determine the equivalent length in the usual manner, determine the flow, as above, and multiply by the flow reduction factor, FR.
For example: Eq Len, L/D FR calc'd FR by Fauske0 1.00 1.00
50 0.8585 0.85100 0.7427 0.75200 0.6425 0.65400 0.5558 0.55
Touchdown Distance by Hoot and Meroney as presented by Gerry Havens, 1987 VC Conference In Boston, p-568Also, Chapter 3, Page 18, Workbook Of Test Cases For Vapor Cloud Source Models / CCPS / AIChE
Bordurtha Eq (1) Max Conc = 3.44*Cs*100*[D/(2*H + hs)]^1.95*vs/U*0.000001Havens Touchdown Distance, X = 0.56*Dj*{(H/Dj)^3*[(2+hs/H)^3-1]*Ua/Uj}^0.5*Frh+Xbar (R1) p-576
Havens Touchdown Conc = 3.1*(Q/U/Dj^2)*((2*H+hs)/Dj)^-1.95/Dv*1000000 (R1) p-576Havens Horizontal Froud No., Frh = Ua/((g*Dj*(RHOj-RHOa)/RHOa))^0.5 (R1) p-576
Havens Xbar = (Dj*Ua/Uj)*Fr^2 (R1) p-576Bordurtha Plume Rise = 1.32*D*(Vs/U)^0.333*SG^0.333*Fr^0.667*0.001
Bordurtha Froud No. Fr = 31.62*Vs/(9.806*D*(SG-1)/SG)^0.5Source Richardson No. = (R2) p-20
u* = (0.065)(Ua)= 0.3250 m/sec (R2) p-20
Wind Velocity, Ua = 5.00 m/s g = 9.815Initial Jet Velocity, Vs = Uj = 63.64 m/s Q = 3.693564 kgms/secRHO, Initial Jet Density 1.7896 kgm/cu.m.RHO air = 1.1786 kgm/cu.m.Jet Diameter, Dj 0.2032 meters D = 203.20 mmBordurtha Froude No., Fr = 77.15 Within HMP Froude No. Range 115.01 to 52.03Havens Horizontal Froude No. = Ffh = 4.92 Within HMP Horizontal Froude No. Range 5.44 to 0.88Havens & Bordurtha Plume Rise, H = 13.05 meters max ht 42.80 ft.Havens X bar, Dist To Max = 95.03 meters downwind distance to max rise 311.76 Existing Stack Height, hs = 32.92 meters 108 ft.Havens C.L. Touchdown Distance 866.96 metersBordurtha Conc'n at Touchdown = 488 ppmvHavens Concentration at Touchdown = 488 ppmvSource Richardson No. = 97.86 Rio > 10 and Dense Gas Model JustifiedExit Nozzle Reynolds No. = 2.31E+06 Re = 6.31(W)/(d)/(Visc cP) (Min.=2.5E04 by Oohms)
Xbar, m = 95.03
Xbar
2,397 ppmv at stack exit elevation14 m
108 Ft. Stack Ht. 488.09 ppmv Concentration at Touchdown 32 m A grade level virtual distance will
be established at this concentrationin a heavy gas model.
(x,y) coords at base of stack=(0,0)TD Radius = 14.39 meters
Touchdown Dis, X TD Area = 650.20 m2866.96 meters
2,844.31 ft.
[g(Dg-Da)/Da](p/4)(Dj)(Uj) / {(Ua)(u*)^2}
(R1)(R2)
8.00
CPQRA Simplified Approaches 05/09/2023
R.A. Hawrelak 01:46:58
All in one eqn with wind at 2m, z = 0 and H = 0 TNO Disp'n Coefficientsppmv = 1/((Dis+VS)^(b+d)/(kgm/s/(PI()*m/s*a*Avg Time Factor*(MW*Atm Press/14.7/1000000/0.082/°K Vap)*c)))Meters = (kgm/s/(PI()*U2*a*ATCF*(ppm*MW*AtmP/14.7/1000000/0.082/°K)*c))^(1/(b+d))-Virt Dis
Senario 1 Scenario 2 Scenario 3 Scenario 4kgms/s = 3.6936 15.44 1.54 3.69 30.8739Wind meas'd @ 10.00 10.00 10.00 10.00 10.00 ft.U10 = 5.00 5.00 5.00 5.00 5.00 m/sWind at = 2.00 2.00 2.00 2.00 2.00 (1) Wind Speed at 2 meters = U2 = U10(2/10)^pWind Corect'n = 0.15 0.15 0.15 0.15 0.15 CPQRA Table 2.3, p-83U2 = 3.93 3.93 3.93 3.93 3.93 Corrected to 2 meters heighta = 0.128 0.128 0.128 0.128 0.128 Stab (1 - 6) = 4b = 0.905 0.905 0.905 0.905 0.905 Rough (1 - 5) 2c = 0.2 0.20 0.20 0.20 0.20d = 0.76 0.76 0.76 0.76 0.76MW = 57.1 57.1 57.1 57.1 57.1 Probit Constant, -5.64 -5.64 -5.64 -5.64 -5.64 Probit Constant, 1.64 1.64 1.64 1.64 1.64 Probit "n" Consta 0.65 0.65 0.65 0.65 0.65Probit = 5.00 5.00 5.00 5.00 5.00 (2.67 = LC01, 3.72 = LC10, 5 = LC50)Atm P = 14.7 14.70 14.70 14.70 14.70° K = 293.3 293.30 293.30 293.30 293.30TD Distance = 866.96 0.00 0.00 866.96 0.00 meters TD Conc = 488.09 1.00E+06 1.00E+06 488.09 1.00E+06 ppmvVirt Dist = 192.69 4.96 1.24 192.69 7.22 meters, (Can set conc = 1,000,000 ppmv and determine Virtual Dist)Sample Time = 100.00 60.00 60.00 100.00 85.00 minutesATCF = 1.5849 1.431 1.431 1.585 1.534 average time correction factor.Conc = 18.23 39.86 39.86 18.23 23.38 ppmvTry Conc = 18.23 18.23 ppmv Dist By CPQRA =TD - VD = 674.27 674.27Dis Fr Virt Dis = 1,195 2,172 545 1,195 4,355 meters 3920.92 ft.ppmv = 18.23 Dis fr Stk = 1,869 Fr All In One Eqn. as a check
EPA and TNO Instantaneous Release Consequence Analysis 05/09/2023
R.A. Hawrelak 01:46:58
EPA PUFF and TNO Point Source Methods For Instantaneous Releases Risk Class Consequence Zone Description Logic Basis: TNO 1979 Yellow Book, EPA Report 600/3-82-078, Wind Corrctd to 2 Meters Ht. 1 100% Certain Fatality > 50% Fatality
2 Wounded / Req Hospitaization Betwenn 1% & 50% Fatality Case Study: BHOPAL AS AN INSTANTANEOUS RELEASE FR PRESSURED VESSEL 3 May Require Hospitalization Between 1% Fatal & IDLH Pr
4 Coughing, Choking, Vomiting Between IDLH Pr & ERPG2 Pr5 No Serious Problems Less Than ERPG2 Probit
Input Data Units Consequences For Special Areas Of Concern (AOCs) Methodology = Chemical Code No. (1-20) = 4 MIC Risk Class = 5 2 3 4 30 Minute IDLH = 5 ppmv fr database Location = Risk Class 1 Risk Class 2 Risk Class 3 Risk Class 4 IDLH Probit Value = 1.6462 fr database Dist Of Concern= 534 3,362 7,549 11,992 60 Minute ERPG2 = 1.00 ppmv fr database Vir Dis @ 100% 0 0 0 0 ERPG2 Probit = 1.0604 fr database Dist For Dispn = 534 3,362 7,549 11,992 Tons of Product Released = 45 Tons Peak C.L. Conc = 66,434.56 585.86 73.28 22.31 Atmospheric Pressure = 14.7 psia Avg Conc = 37,505 331 41 13 Amount Vaporized at Atm = 1 Wt. Frac <1.0 to 0.01> Exposure Min. = 0.69 3.63 7.55 11.47 Temp Of Flash Vapor = 77 F <Default to Amb Temp> Dose(C^n)(t)= 6.66E+02 1.60E+02 8.58E+01 6.00E+01 MW of Vapor = 57.1 fr database Probit = 5.0000 2.6700 1.6462 1.0604 Std Deviations For Cloud = 2.15 < 2.15 For 90% of cloud > % Fatality = 50.17% 0.94% 0.00% 0.00% Initial Dilution = 1.0000 Vol Frac <1.0 to 0.01> Risk Conseq = No Problems Wounded>Hospit May Req Hospit Cough/Chkg/Vom PUFF Methodology = 1 (EPA = 1, TNO = 2) Cld Arriv Time= 2.26 14.27 32.03 50.88 k1 Dose Constant = -5.642 fr database Consequence Summary (With Virtual Distance, If Any) Methodology = k2 Dose Constant 1.637 fr database n Dose Constant = 0.653 fr database Consequence EPA Dist Fr Peak C.L. Fixed on C.L. Ambient Temp = 77 F < Cloud Temp Default > % Fatality Source, m Conc, ppmv Avg PPMV Exp Min. Wind Speed Referenced at = 10 Meter Height 100 50 Out Of Range Out Of Range Out Of Range Wind Speed At Ref Ht. = 11.1835 mph m/s= 5.00 90 194 893,514 504,426 0.27 Wind Speed Correctd to 2m = 8.78 mph m/s= 3.93 80 275 365,686 206,445 0.38 LC50 Peak Concentration = 66,434.56 ppmv (for Briggs Only) 70 354 190,955 107,802 0.47 Stability Class A,B,C,D,or F D Stabil Class =4 60 438 110,368 62,308 0.57 Ground Roughness (1 to 5) = 2 Rural, Zo = 0.1m 50 534 66,435 37,505 0.69 Wind Variation, +/- ° 20.00 +/- Degrees 40 650 39,989 22,576 0.82 Wind Speed Ht Corr Factor = 0.15 CPQRA, Table 2.3, p-83 30 805 23,113 13,048 1.00
20 1,036 12,069 6,814 1.25 Alternate Disp'n Coeff'ts 10 1,467 4,940 2,789 1.71 Briggs Dispn Checking Only For Checking Dist 1 3,362 586 331 3.63 Initialization Counter 2 1 resets Newton Rapson IDLH 7,549 73 41 7.55 Distance to LC50 Conc = 0.5722 km. - Briggs Disp'n Coef ERPG2 11,992 22.31 13 11.47
EPA and TNO Instantaneous Release Consequence Analysis 05/09/2023
R.A. Hawrelak 01:46:58
Betwenn 1% & 50% Fatality Between 1% Fatal & IDLH Pr Between IDLH Pr & ERPG2 Pr Less Than ERPG2 Probit
EPA
Units meters meters meters ppmv ppmv minutes ppmv-min Probit Fr Probits See Above min., W@ 2m
EPA2 m Wind Vel
Cloud Time OfArrival, Min.
0.210.821.171.501.862.262.763.414.406.22
14.2732.0350.88