Evaporator Calculator
Concentrating 10,000 kg/h of a 5 % solution to 25 % in a single effect boiling at 100 °C takes 9562.22 kg/h of 120 °C steam.
Saturated steam at 120 °C: 2202 kJ/kg.
9562.2161671208 kg/h
Full answer, then cut to fewer decimals (not rounded):
- 9562.2161671208 kg/h
- 9562.216167120 kg/h
- 9562.21616712 kg/h
- 9562.2161671 kg/h
- 9562.216167 kg/h
- 9562.21616 kg/h
- 9562.2161 kg/h
- 9562.216 kg/h
- 9562.21 kg/h
- 9562.2 kg/h
- Product rate P = F x_F/x_P
- 2000 kg/h
- Water evaporated V = F − P
- 8000 kg/h
- Heat load Q
- 5848.888889 kW
- Steam economy V/S
- 0.8366261398
- Heat transfer area A = Q/(UΔT)
- 146.2222222 m²
Step-by-step solution
- P = 10000 × 0.05 ÷ 0.25 = 2000 kg/h; V = 8000 kg/h
- Q = F c_p (T₁ − T_F) + V λ = 3000000 + 18056000 = 21056000 kJ/h
- S = Q/λ_s = 9562.216167 kg/h
Evaporator Formula
S λ_s = F c_p (T₁ − T_F) + V λ
P = F x_F/x_P, V = F − P, economy = V/S, A = Q/(U ΔT)
Worked Example
10,000 kg/h of 5 % solution fed at 25 °C, concentrated to 25 % at 100 °C with 120 °C steam:
- P = 10000 × 0.05 ÷ 0.25 = 2000 kg/h; V = 8000 kg/h
- Q = F c_p (T₁ − T_F) + V λ = 3000000 + 18056000 = 21056000 kJ/h
- S = Q/λ_s = 9562.216167 kg/h
Water evaporated V = F − P: 8000 kg/h · Heat load Q: 5848.888889 kW · Steam economy V/S: 0.8366261398 · Heat transfer area A = Q/(UΔT): 146.2222222 m²
GATE tip
Boiling-point rise of strong solutions reduces ΔT = T_s − T₁; take T₁ as the solution’s boiling point, not water’s.
More Mass Transfer Calculators
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Fick’s Law Calculator
N_A = (D_AB P / RTz) ln[(P − p_A2)/(P − p_A1)]
equimolar: N_A = D_AB (p_A1 − p_A2)/(RTz)
Example: Water evaporating at 25 °C through 10 mm of still air (D = 0.26 cm²/s): Molar flux N_A = 0.00337961 mol/(m²·s).
-
Fenske Equation Calculator
N_min = ln[(x_D/(1 − x_D))((1 − x_B)/x_B)] / ln α
N_min includes the reboiler as a stage
Example: Separating to 95 % and 5 % with α = 2.5: Minimum number of stages N_min = 6.42687.
-
Minimum Reflux Ratio Calculator
Σ αxF/(α − θ) = 1 − q; R_min + 1 = Σ αxD/(α − θ)
saturated liquid feed (q = 1): R_min = [x_D/x_F − α(1 − x_D)/(1 − x_F)]/(α − 1)
Example: A saturated-liquid feed at 50 % with α = 2.5 and 95 % distillate: Minimum reflux ratio R_min = 1.1.
-
Kremser Equation Calculator
N = ln[((y_N+1 − mx₀)/(y₁ − mx₀))(1 − 1/A) + 1/A] / ln A
A = L/(mV); N = (y_N+1 − y₁)/(y₁ − mx₀) when A = 1
Example: Absorbing a gas from 5 % to 0.5 % with pure solvent, m = 1.2 and L/V = 1.8: Number of ideal stages N = 3.41902.
Frequently asked questions
Why is steam economy below 1 in a single effect?
Steam must also heat the feed to boiling, so less than 1 kg of water evaporates per kg of steam when the feed is cold.
How do multiple effects help?
Vapour from one effect heats the next, so an n-effect evaporator gives roughly n kg of evaporation per kg of steam.
Sources
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
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APA
Scientific Converters. (2026, October 15). Evaporator Calculator. Retrieved October 29, 2026, from https://scientificconverters.com/calculators/evaporator-calculator/
IEEE
Scientific Converters, "Evaporator Calculator," scientificconverters.com. Accessed: Oct. 29, 2026. [Online]. Available: https://scientificconverters.com/calculators/evaporator-calculator/