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Plant Engineering Calculator

Updated Sep 17, 2026

Steam Desuperheating Water Calculator — Spray Water Flow & Outlet Steam

Estimate spray-water flow for steam desuperheating from a transparent steady-state energy balance.

Live calculationWorking shownPrivate in browser

Inputs

Results

Spray water 1050.4 kg/h
Outlet total flow 11050.4 kg/h
Water/steam ratio 10.50 %
Removed steam enthalpy rate 694.4 kW
More actions

Shared links reopen these inputs. Recent and saved calculations stay in this browser unless you clear site data.

Formula

mw=ms(hin−hout)/(hout−hw).

Your calculation, step by step

These steps use the values currently entered above so the result can be checked independently.

  1. 1.Steam enthalpy reduction = 250.0 kJ/kg.
  2. 2.Spray-water pickup to outlet state = 2380.0 kJ/kg.
  3. 3.Spray flow = 10000 × 250.0 ÷ 2380.0 = 1050.4 kg/h.

How to use this calculator

  1. Enter measured or design values using the units shown beside each field.
  2. Review the live results and the substituted calculation steps before using the estimate.
  3. Check the assumptions below, then continue to a related calculator when the next engineering decision needs another model.

Worked example

10,000 kg/h steam dropping from 3,050 to 2,800 kJ/kg with 420 kJ/kg spray water needs about 1,050 kg/h water.

Assumptions and limits

  • Enter enthalpies from a validated steam-property source at actual pressure.
  • Assumes adiabatic mixing with no separator loss or external heat transfer.

How to interpret the result

Treat the primary result as an engineering screening value, then use the secondary outputs to understand scale, energy or operating impact. Confirm site measurements, equipment limits and applicable standards before making a design or control change.

Questions engineers ask

How much spray water is needed to desuperheat steam?

The required spray flow follows an energy balance between incoming steam, target outlet steam and injection water. Using enthalpy rather than only temperature is important because steam properties vary with pressure and state.

Which spray-water enthalpy should I enter?

Use the enthalpy of the actual injection water at its supply condition from a validated property source. Using an arbitrary room-temperature value can materially distort the result.

Can the calculated spray flow size an attemperator?

It is a thermal screening flow, not a complete hardware selection. Final sizing also needs nozzle turndown, atomization, straight-run requirements, pressure differential, evaporation distance and OEM limits.

Continue the calculation

Use the next calculator in the same engineering workflow instead of restarting from search.

steam superheat energysteam qualitysteam vent loss
Methodology. MAXScanner shows the governing formula, entered values and calculation outputs so the estimate is auditable. The calculator is a screening aid; assumptions and equipment-specific limits remain part of the engineering review.