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Condensing Steam

Reference data and engineering information about condensing steam for steam and condensate applications.

condensingsteam

Overview

Engineering reference data for Condensing Steam in steam condensate.

Key Formulas

Steam Quality

x=mvmtotalx = \frac{m_v}{m_{total}}

Mass fraction of vapor in two-phase mixture.

Enthalpy of Wet Steam

h=hf+x⋅hfgh = h_f + x \cdot h_{fg}

Specific enthalpy of wet steam.

Flash Steam

mflash=mliquidhf−hf2hfg2m_{flash} = m_{liquid} \frac{h_f - h_{f2}}{h_{fg2}}

Steam generated when condensate flashes to lower pressure.

Condensate Load

mc=Qhfgm_c = \frac{Q}{h_{fg}}

Condensate generated by heat transfer.

Variables

SymbolDescriptionUnit
xxSteam quality—
hfh_fEnthalpy of saturated liquidkJ/kg
hfgh_{fg}Latent heat of vaporizationkJ/kg
hhSpecific enthalpykJ/kg
QQHeat transfer ratekW

Worked Examples

Example 1: Heat Released from Condensing Steam Calculate the heat released when condensing 5 kg of steam at atmospheric pressure (100 °C). The specific evaporation enthalpy is 2257 kJ/kg.

Using the formula for heat released: Q=he⋅MsQ = h_e \cdot M_s

Substituting the values: Q=(2257 kJ/kg)×(5 kg)=11,285 kJQ = (2257 \ \text{kJ/kg}) \times (5 \ \text{kg}) = 11,285 \ \text{kJ}

Example 2: Heat Transfer Rate in a Condensing Steam Flow Determine the heat transfer rate (power) for a condensing steam flow rate of 8 kg/h (0.0022 kg/s) at atmospheric pressure (100 °C). The specific evaporation enthalpy is 2257 kJ/kg.

Using the formula for heat transfer rate: q=he⋅m˙sq = h_e \cdot \dot{m}_s

Substituting the values: q=(2257 kJ/kg)×(0.0022 kg/s)=5 kW (kJ/s)q = (2257 \ \text{kJ/kg}) \times (0.0022 \ \text{kg/s}) = 5 \ \text{kW} \ (\text{kJ/s})

Steam Properties Reference

The specific evaporation enthalpy (heh_e) varies with pressure and temperature. For accurate calculations, consult the Properties of Saturated Steam tables available for both Imperial (Btu/lb) and SI (kJ/kg) units.

References

Source: engineeringtoolbox.com