Some common steam and condensate equations can be expressed as Steam Heating
ms = H / 960
Where
• ms = steam mass flow rate (Lbs /hr)
• H = heat flow rate (Btu/hr)
Steam Heating Liquid Flow
Ms = QL x 500 x SGL x CPL x ▲T / L S
Where
• Ms = steam mass flow rate (Lbs /hr)
• QL = volume flow liquid (GPM)
• SGL = specific heat capacity of the liquid (Btu/lb °F)
• CPL = specific gravity of the fluid
• ▲T = temperature difference liquid (°F)
• L S =latent heat of steam at steam design pressure (Btu/lb)
Steam Heating Air or Gas Flow
ms = QG x 60 x ρG x CPG x ▲TG / LS
Where
• ms = steam mass flow rate (lbs /hr)
• QG = volume flow gas (CFM)
• ρG = density of the gas (lb/ft3 )
• CPG = specific gravity of the gas (Air CPG = 0.24 Btu/Lb)
• ▲TG = temperature difference gas (0F)
• LS = latent heat of steam at steam design pressure (Btu/lb)
Steam Pipe Sizing Equations
▲P = [(0.01306 x W2 x (1+ 3.6/ID)] / (3600 x D x ID5)
W = 60 x {(P x D x ID5) / [0.01306 x (1+3.6 / ID)]}1/2
W = 0.41667 x V x AINCHES x D = 60 x V x AFEET x D
V = 2.4 x W/ AINCHES x D = W / (60 x AFEET x D)
Where
• ▲P = Pressure Drop per 100 Feet of Pipe (Psig/100 feet)
• W = Steam Flow Rate (Lbs /Hr)
• ID = Actual Inside Diameter of Pipe (Inches)
• D = Average Density of Steam at System Pres sure (Lbs/Cu-ft)
• V = Velocity of Steam in Pipe (Feet/Minute)
• AINCHES = Actual Cross Sectional Area of Pipe (Sq-inches)
• AFEET = Actual Cross Sectional Area of Pipe (Sq-ft)
Steam Condensate Pipe Sizing Equations
FS = (Hss – Hsc) / HLC x 100
WCR = FS / 100 x W
Where
• FS = Flash Steam (Percentage %)
• Hss = Sensible Heat at Steam Supply Pressure (Btu/Lb)
• Hsc = Sensible Heat at Condensate Return Pressure (Btu/Lb)
• HLC = Latent Heat at Condensate Return Pressure (Btu/Lb)
• W = Steam Flow Rate (Lbs/Hr)
• WCR = Condensate Flow based on percentage of Flash Steam created during condensing
process (Lbs/hr)
Use this flow rate in steam equations above to determine condensate return pipe size.
