🔄 Rotary Regenerator Sizer (Ljungström APH)

Size boiler rotary air preheaters (Ljungström APH): thermal effectiveness, matrix heat capacity ratio Cr*, preheated air temp, and sulfuric acid dew point limit.

⚡ Fortran 90 Engine Double Precision (IEEE 754) ✓ ISO / ASME Validated

📊 Solver Telemetry ● ACTIVE

👁️ Consultations 15

⚡ Calculs faits 13

💾 Téléchargements 364 📦 Code Fortran 4.1 KB

📅 Mise en service Jun 2026

⏱️ Latence < 1 ms

🔄 Rotating Ljungström Wheel & Counterflow Matrix Sectors

Real-time visual simulation: Flue gas heating left sector, cold combustion air absorbing heat on right sector

📝 Configuration & Presets

⚡ 500 MW Coal Boiler APH 🛢️ Refinery Heavy Oil APH 🪵 Biomass CFB Boiler 🔥 Industrial Gas Boiler

🔥 Boiler Fuel & Flue Gas Stream

Boiler Fuel / Flue Gas Medium:

Flue Gas Flow ṁ_gas [kg/s]:

Flue Gas Inlet T_g,in [°C]:

💨 Combustion Air Stream

Combustion Air ṁ_air [kg/s]:

Air Inlet Temp T_a,in [°C]:

📐 Rotor Wheel Dimensions & Rotation

Rotor Diameter D [m]:

Matrix Depth L [m]:

Rotor Speed N [rpm]:

Matrix Mass [tonnes]:

Ljungström Regenerator Formulation:
• Matrix Capacity: C_r = M_mat · c_mat · (N/60) [W/K]
• Capacity Ratio: C_r^* = C_r / C_min
• Kays & London Effectiveness: ε_reg = ε_cf · [ 1 − 1 / (9 · (C_r^*)^1.93) ]
• Heat Recovery: Q̇ = C_air · (T_a,out − T_a,in) [MWth].

📊 Performance Results

📊 Output Summary
💾 Fortran Source

Recovered Thermal Duty (Q̇)

14.03 MWth

Regenerator Effectiveness: 86.7% | Matrix C_r*: 4.89

WARNING: ACID DEW POINT CORROSION

Preheated Combustion Air Temp 253.3 °C Boost = +238.3 °C

Cooled Flue Gas Exit Temp 89.2 °C Acid dew point = 120 °C

Acid Dew Point Margin +-30.8 K Corrosion safety margin

Rotor Wheel Diameter 4.50 m 2 RPM | 18 tonnes

📈 Recovered Heat Duty Q̇ (MWth) vs Rotor Speed N (rpm)

📉 Cooled Gas Exit Temp (°C) vs Flue Gas Inlet Temp (°C)

=================================================================
 THERMOFLUIDCALC — ROTARY REGENERATOR (LJUNGSTRÖM) REPORT
=================================================================
Case Title                 : Biomass CFB Boiler Air Preheater
Fuel / Flue Gas Medium     : Biomass Wood Pellet Boiler Flue Gas (T_dew = 120°C)
Flue Gas Stream            : mg = 65.00 kg/s, Tg_in = 290.0 C
Combustion Air Stream      : ma = 58.00 kg/s, Ta_in = 15.0 C
Rotor Dimensions           : D = 4.50 m, Depth = 1.40 m, N = 2.00 rpm, Mass = 18.0 tonnes
-----------------------------------------------------------------
RECOVERED THERMAL DUTY (Q) : 14.03 MWth
Regenerator Effectiveness  : 86.66%
Matrix Capacity Ratio (Cr*): 4.89
Preheated Air Outlet Temp  : 253.31 deg C
Cooled Flue Gas Exit Temp  : 89.22 deg C
Acid Dew Point Margin      : +-30.78 K (WARNING: ACID DEW POINT CORROSION)
=================================================================

📘 Calculation Methodology & Rotary Regenerator Standards

Ljungström Rotary Wheel Mechanism

A slowly rotating corrugated steel matrix transfers thermal energy periodically between the hot flue gas exhaust and cold incoming combustion air, saving millions of dollars in annual boiler fuel.

Sulfuric Acid Dew Point Constraint

In sulfur-bearing fuels (coal, heavy fuel oil), sulfur trioxide ($SO_3$) combines with moisture to form sulfuric acid ($H_2SO_4$) mist if flue gas drops below $130 - 145^\circ\text{C}$.

Key Engineering Assumptions

Modified Kays & London $\epsilon-NTU-C_r^*$ rotary heat exchanger formulation.
Soot blowing and radial/circumferential air-to-gas leakage seal allowances.
Widely used on thermal power plants, cement kilns, and refinery process heaters.

ThermoFluidCalc Engineering Report