Transcript

Sizing

Pressure Regulators &
Control Valves

CAPACITY REDUCTION TABLE: REGULATOR INTEGRAL SLAM SHUT INTEGRAL MONITOR INTEGRAL SILENCER APERFLUX 851 -5% -5% -5% REFLUX 819 -7% -7% -5% REFLUX 819/FO -7% -7% -5% APERVAL SA -10% SB -5% -5% -5% REVAL 182 SA -10% SB -7% -7% -5% Not applicable DIXI -3% Not applicable DIVAL 600 0% Not applicable 0% NORVAL -7% Not applicable Not applicable NORVAL 608 -7% Not applicable -10% Pu . when the values of Pu.526 x Pu x sin K1x Pd x ( Pu . 526 x Cg x Pu x sin K 1 x ( A-2 in critical conditions: (Pu ≥2xPd) Q = KG 2 x Pu Q = 0 . Flow rates at fully open position and various operating conditions are related by the following formulae where: Q = flow rate in Stm3/h Pu = inlet pressure in bar (abs) Pd = outlet pressure in bar (abs). and hence the regulator size. the flow rate can be calculated as follows: A-1 in sub critical conditions: (Pu<2xPd) Pd x ( Pu . Pd and Q are known. as well as Pu and Pd.Pd Pu ( .Pd ) B-2 in critical conditions (Pu ≥2xPd) KG = 2xQ Cg = Pu Q 0.Pd ) Q = KG x ( Pu .the Cg or KG values. A > When the Cg and KG values of the regulator are known. may be calculated using: B-1 in sub-critical conditions: (Pu<2xPd) Q KG = Q Cg = ( 0 .Pd Pu Q = 0 . 526 x Cg x Pu B > Vice versa.Sizing the Pressure Regulators Sizing of regulators is usually made on the basis of Cg valve and KG sizing coefficients.526 x Pu NOTE: The sin val is understood to be DEG.

53 2. .0 .15 + tu ) Correction factors FC Type of gas Air Propane Butane Nitrogen Oxygen Carbon dioxide Relative density 1.78 0. to avoid premature erosion phenomena and to limit noise emissions. CAUTION: in order to get optimal performance. must be multiplied by a correction factor Fc.14 1. calculated as above.97 1. the value of the flow rate.The above formulae are applicable to natural gas having a relative density of 0.79 0.52 Fc Factor 0. 92 x x 2 1 + Pd DN where: V = Q = DN = Pd = gas speed in m/sec gas flow rate in Stm3/h nominal size of regulator in mm outlet pressure in barg.61 w. 002 x Pd V = 345 .r.73 0.8 Fc = S x ( 273.55 0. as follows: 175.63 0.0 0.t. air and a regulator inlet temperature of 15°C.63 Lists the correction factors Fc for anumber of gases at 15°C. Gas speed at the outlet flange [m/sec] 450 400 350 300 250 200 150 100 50 0 0 5 10 15 20 25 30 35 40 45 50 55 Outlet pressure [bar] The gas speed at the outlet flange may be calculated by means of the following formula: Q 1 . it is recommended to check gas speed at the outlet flange does not exceed the values of the graph below.0 1. For gases having a different relative density d and temperature tu in °C.

78 106.78 106.Cg and Kg valve coefficient Tables Aperflux 101 50 2” 1682 1768 103 Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor 80 3” 4200 4414 108 Aperflux 851 Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor 25 1" 480 505 113.78 106.9 80 3" 3790 3979 113.9 Reflux 819 Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor 25 50 80 100 150 200 250 1" 2" 3" 4" 6" 8" 10" 575 2220 4937 8000 16607 25933 36525 605 2335 5194 8416 17471 27282 38425 106.9 50 2" 1550 1627 113.78 106.78 106.9 100 4" 5554 5837 113.78 106.78 106.78 Reflux 819/FO Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor 25 50 80 100 150 200 250 1" 2" 3" 4" 6" 8" 10" 575 2220 4937 8000 16607 25933 36525 605 2335 5194 8416 17471 27282 38425 106.78 106.78 106.9 250 10" 24548 25850 113.78 106.78 106.9 200 8" 17316 18199 113.78 106.78 .9 150 6" 11112 11678 113.

5 25 1" 140 147 93.78 106.78 106.78 K1 body shape factor Nominal diameter (mm) 25 1" Size (inches) 130 Cg flow coefficient 136 KG flow coefficient K1 body shape factor 106.Dival 160 AP Dixi AP Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor 25 1" 159 167 99.78 Aperval 101 Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor 50 2” 2091 2199 108 80 3” 4796 5045 108 100 4” 7176 7546 108 Aperval Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor 25 1" 584 613 90 50 2" 1978 2077 101 65 2"1/2 3530 3706 101 80 3" 4525 4751 101 100 4" 6719 7055 101 .5 Staflux 187 Staflux 185 25 50 80 Nominal diameter (mm) 1" 2" 3" Size (inches) 439 1681 3764 Cg flow coefficient 462 1768 3960 KG flow coefficient 106.

78 106.78 106.78 Terval Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor 50 2" 1706 1796 108 65 2"1/2 2731 2875 104 80 3" 3906 4112 100 100 4" 5490 5775 100 50 2" 1667 1755 104 65 2"1/2 2793 2940 104 80 3" 4099 4315 106 100 4" 5660 5954 106 25 1" 540 567 96 40 1"1/2 983 1034 96 50 2" 1014 1066 96 Terval/R Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor Dixi Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor .Cg and Kg valve coefficient Tables Reval 182 50 65 80 100 150 200 250 Nominal diameter (mm) 25 1/2 1" 2" 4" 6" 2" 3" 8" 10" Size (inches) 575 2220 3320 4937 8000 16607 25933 36525 Cg flow coefficient 605 2335 4197 5194 8416 17471 27282 38425 KG flow coefficient K1 body shape factor 106.78 106.78 106.78 106.78 106.78 106.

Dival 600 Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor Dival 700 Head ø 280 25 40 50 1" 1"1/2 2" 269 652 781 283 685 821 94 94 86 Head ø 280/TR 25 40 50 1" 1"1/2 2" 315 692 770 331 727 809 97 95 97 See the capacity Table Norval 40 50 Nominal diameter (mm) 25 1" 1"1/2 2" Size (inches) 331 848 1360 Cg flow coefficient 348 892 1430 KG flow coefficient K1 body shape factor 106.78 65 80 100 150 200 2"1/2 3" 4" 6" 8" 2240 3395 5100 10600 16600 2356 3571 5365 11151 17463 106.78 106.78 106.78 Norval 608 Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient K1 body shape factor 50 2" 1700 1788 106 80 3" 3500 3681 106 .78 106.78 106.78 106.78 106.

526 x Cg x Pu x sin (106.Cg and Kg valve coefficient Reflux 919 .8 x Pu (valid for Pu < 2 x Pd) Q Cg = ( ( 0. as well as Pu and Pd.Pd ( Pu Q = 0.78 KG = 2xQ Pu Cv = Pu .8 x Cv x Pu x sin (106. For gases with different relative specific gravity (S) and temperature t (in °C) ).Syncroflux .Cg coefficient corresponds numerically to the value of air flow in SCF/H in critical conditions with full open valve operating with an upstream pressure of 1 psia at a temperature of 15°C.8 x Cv x Pu Q= 0. Cv.526 .VLM Nominal diameter (mm) Size (inches) Cg flow coefficient KG flow coefficient Cv flow coefficient 25 1" 575 605 18 50 2" 2200 2335 69 80 3" 4937 5194 154 100 4" 8000 8416 250 150 200 6" 8" 16607 25933 17471 27282 519 810 250 10" 36525 38425 1141 . Pd and Q are known.1 > in non critical conditions: (Pu . when the values of Pu.Pd ( Pu 16. calculate the values of Cv.15 + tu ) Reflux 919 . Above formulae are valid for natural gas with a relative specific gravity of 0.Pd ) 2. Cg formulae give flow rate values more correct while KG formulae give values 5% higher than real ones only in noncritical conditions. In the case of noise limitation level a speed at the outlet flange of 130 m/sec.KG.8 .78 1.78 Cg = Q 0.VLM Sizing the Control Valve Choise of the valve is usually on the basis of Cg valve and Cg flow rate coefficients. the flow rate can be calculated as follows: Q = KG 1.2 > in critical conditions: Q = KG 2 x Pu Pu .2 > in critical conditions: Q Cv = ( 16. x Pu x sin x 106.Pd) Pd Q = Pu .Pd Pu Q 16. are bound by the following formule where: Pu = inlet pressure in bar (abs) Pd = outlet pressure in bar (abs) Q = flow rate in Stm/H KG.8 Fc = S x ( 273.78 (valid for Pu < 2 x Pd) (valid for Pu ≥ 2 x Pd) Q= 16. value of flow rate calculated as above. coefficient corresponds numerically to the value of natural gas flow rate in Stm/h in critical conditions with full open valve operating with an upstream pressure of 2 bar abs at a temperature of 15°C.Syncroflux . Cg = valve coefficent 1 > When the Cg and KG values of the control valve are known.526 x Pu Pu . Flow rates at full open position and various working conditions.61 compared to air and temperature of 15° C at inlet. must be adjusted multiplying by: 175. it is also raccomanded.526 x Cg x Pu 2 > Vice versa. x Pu x sin x 106.Pd Pu ( (valid for Pu ≥ 2 x Pd) A oversizing of 20% on calculated values is raccomanded. Cg or KG with: KG = Q Pd ( Pu .

5F2 P1) Volume flow rate (gas and vapor) PΔ (P1+P2) GT Q = 290 Cv Weight flow rate (gas and vapor) GΔP (P1+P2) T Q = 355 Cv Weight flow rate (saturated steam) W = 13.5F2 P1) Constant liquid/gas mixture ratio (liquid containing non condensable gas or liquid containing high title vapor) W = 19.5F2 P1) Volume flow rate (gas and vapor) Q= 262 F Cv P1 GT W = 13.00126 Δ t) 100 w2 = Xg (Vg2-Vf) + 100 Vf .Deltaflux Sizing the Control Valve GAS.5F2 P1) Constant liquid/gas mixture ratio (liquid containing non condensable gas or liquid containing high title vapor) B. VAPOR AND STEAM A.5) Weight flow rate (gas and vapor) W = 321 F Cv P1 G T Weight flow rate (saturated steam) W = 19.55 BIPHASE FLUIDS ΔP (P1+P2) (1+0.1 Cv ΔP w1 ΔP (P1+P2) Weight flow rate (overheated steam) W = 13.5 F Cv P1 (w1+w2) Variable liquid/vapor mixture ratio (liquid containing low title vapor.73 F Cv P1 (1+0. Critical conditions (when ΔP 0.1 F Cv P1 w1 100 w1 = Xg (Vg1-Vf) + 100 Vf W = 11.00126Δt) B.5) W = 27.73 F Cv P1 Weight flow rate (overheated steam) W = 11.1 Cv ΔP (w1+w2) Variable liquid/vapor mixture ratio (liquid containing low title vapor. less then 0. less then 0. Critical conditions (when ΔP ≥ 0. Subcritical conditions (when ΔP < 0.55 Cv Cv A. Subcritical conditions (when ΔP < 0.

Subcritical conditions (when ΔP < F2 ΔPc) B.013 bar abs: Sm3/h = volume flow rate: m3/h = weight flow rate: Kg/h = upstream mixture density: kg/m3 = downstream mixture density: kg/m3 = specific volume of liquid: m3/kg = specific volume of gas or vapor at upstream pressure: m3/kg = specific volume of gas or vapor at downstream pressure: m3/kg . Glossary Cv = valve flow rate coefficient: US gpm of water with ∆P = 1 psi ΔP = valve pressure drop P1-P2: bar ΔPc = maximum dimensioning differential pressure: bar ΔPk = cavitation differential pressure: bar = overheating temperature delta t1 . Critical conditions (when ΔP ≥ F2 ΔPc) Volume flow rate Qf = Cv 1.28 Pv ) Pk ΔPk = Kc (P1-Pv) Note: For values of ΔP ≥ ΔPk the valve works under cavitation conditions.ts: °C Δt = valve recovery factor: non dimensional F = gas relative density (air=1): non dimensional G Gf = liquid relative density at operating temperature (water at 15°C=1) Kc = valve incipient cavitation factor: non dimensional Xg = weight percentage of gas or vapor in the mixture at upstream pressure: % P1 = valve upstream pressure: bar abs P2 = valve downstream pressure: bar abs Pc Pk Pv T t1 ts Q Qf W W1 W2 Vf Vg1 Vg2 = vena contracta critical pressure: bar abs = thermodynamic critical point pressure: bar abs = vapor pressure at operating temperature: bar abs = upstream gas absolute temperature (273+°C): °K = overheated steam upstream temperature: °C = saturated steam temperature at upstream pressure: °C = volume flow rate at 15 °C and 1.17 Volume flow rate ΔP Gf Qf = Weight flow rate F Cv 1.96-0.Deltaflux Cg and Kg valve coefficient LIQUIDS A.17 ΔPc Gf Weight flow rate W = 855 Cv GfΔP W = 855 F Cv Gf ΔPc ΔPc = P1-Pc Pc = Pv (0.

in detail. for the dimensioning of Deltaflux control valves bigger than 24”. .p.A. always refer to Pietro Fiorentini S.Deltaflux Cv coefficient Deltaflux Dn 2" 3" 4" 6" 8" 10" 12" 14" 16" 18" 20" 24" Cv coefficient at 100% opening 82 215 405 1080 1750 2860 3980 5000 6800 8400 10600 16100 Deltaflux Dn 2" 3" 4" 6" 8" 10" 12" 14" 16" 18" 20" 24" Cv coefficient at 100% opening 60 150 290 650 1225 1975 2825 3475 4675 5950 7500 11100 Liquid control application Liquid trim Gas control application Gas trim Note: To verify the dimensioning and.

pressure loss can still be calculated with the above formula.8 S x ( 273 .Sizing the Slam Shut Valves Calculation of the pressure drop The following formula can be used to calculate pressure losses of the slam shut valve in fully open position: 2 2 2 Δp = KG x Pu . replacing the value of the flow coefficent in the table with: KG1 = KG x 175 .(KG x Pu ) .61 (air=1) temperature of 15 °C at valve inlet.4Q 2 x KG Δp = pressure loss in bar Pu = absolute inlet pressure in bar Q = flow rate Stm3/h KG = flow coefficient Pressure loss calculated as above is referred to natural gas with specific gravity of 0. for gases with different specific gravity S and temperatures t °C. 15 + t ) .

SBC 782 Nominal diameter (mm) 25 1" Size (inches) 510 KG flow coefficient 50 2" 1970 65 2"1/2 3550 80 3" 4390 100 4" 7120 150 6" 14780 200 8" 23080 SCN Nominal diameter (mm) 25 1" Size (inches) 549 KG flow coefficient 40 1"1/2 1116 50 2" 1788 65 2"1/2 2603 80 3" 4086 100 4" 6122 HBC 975 Nominal diameter (mm) Size (inches) KG flow coefficient 100 4" 7120 150 6" 14780 200 8" 23080 25 1" 500 40 1"1/2 860 50 2" 976 Dilock 108 Nominal diameter (mm) Size (inches) KG flow coefficient 250 10" 32470 150 200 6" 8" 13680 21700 250 10" 32506 .

9 x C) • P1 A • M Z1 T1 q M Q = 23. in Kg/h Q = maximum flow rate (Stm3/h) A = minimum area (cm2) (see table) Kc = outflow coefficient P1= setting pressure plus a 10% overpressure (bar abs) T1= temperature in °K of the fluid at the valve inlet during the discarge.9 = safety coefficient M = molecular mass of the fluid in Kg/Kmol (see table) Z1 = compressibiliti factor of the fluid under the P1 conditions to be considered approximately equal to one if the actual values is not known.661 q = maximum flow rate to be discharged. 0. Cp = specific heat at consistant pressure Cv = specific heat at consistant volume C = coefficient of expansion = C = (see table) k( 2 k+1 ) k+1 k-1 . k= Cp Cv exponent of equation of the isentropic expansion under the P1 and T1 conditions.9 Kc) • (394.Sizing the Safety Relief Valves Calculation of the safety relief valves The flow rate is calculated by the following formulae: q = (0. reported by user or by designer.

PVS 782 Nominal diameter (mm) Size (inches) Calculation area (cm2) Outflow coefficient K 25 1" 4.669 0.686 0.56 0. Relative density Carbon dioxide Hydrogen Methane Natural gas* Nitrogen Oxigen Propane * Medium value Molecular mass M 28.09 Coefficient of expansion C 0.01 2.03 0.56 80 3" 43.02 16.56 Molecular mass and expansion coeff.04 28.56 150 200 6" 8" 168.71 0.02 32.668 0.00 44.685 0.56 50 2" 20.01 0.66 0.56 259.669 0.685 0.04 18.56 100 4" 74.685 0.59 0.635 Pressure Capacity table versus pressure Nominal diameter (mm) Size 2 barg 10 barg 20 barg 30 barg 40 barg Flow rate (Kg/h) 25 1" 332 1885 2472 5337 7063 50 2" 2144 8016 15357 22697 30038 80 3" 4604 17214 32976 48738 64500 100 4" 7991 29881 57242 84603 111964 150 6" 18043 67462 129235 191008 252781 200 8" 27788 103894 199028 294161 389295 .97 44.

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