STEAM & CONDENSATE EQUATIONS

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.