Steam Requirement

\[\dot{m}_s=\frac{Q}{h_s-h_c}\]

Variables

mssteam mass flow rate (kg/s)

Qheat duty (kW)

hssteam specific enthalpy (kJ/kg)

hccondensate specific enthalpy (kJ/kg)

Description

What is this formula?

The steam requirement formula calculates the amount of steam needed to deliver a specified heat duty in a process heater, heat exchanger, reactor, evaporator, or other thermal equipment.

When to use it

Use this equation when sizing steam systems, estimating utility consumption, or performing energy balances in industrial plants.

Example

A heat exchanger requires 500 kW of heat. Saturated steam enters with an enthalpy of 2760 kJ/kg and leaves as condensate with an enthalpy of 505 kJ/kg.

Formula:

ms = Q / (hs - hc)

Substitution:

ms = 500 / (2760 - 505)

ms = 500 / 2255

Result:

ms = 0.222 kg/s

Approximately 0.222 kg/s of steam is required.

Applications

- Steam utility systems

- Heat exchanger design

- Process heating calculations

- Evaporator design

- Industrial energy balances

Note

This equation assumes that all available steam enthalpy is transferred to the process and that heat losses are negligible. Actual steam consumption may be higher due to equipment inefficiencies, condensate losses, and heat leakage.