Rotary Dryer Heat & Mass Balance Calculator

Calculate rotary drum dryer water evaporation rates, dry product output, combustion air mass flow, thermal energy duty, and natural gas fuel consumption.

Material Feed & Moisture Content

Wet Feed Rate (tons/hr):

Solids Specific Heat (BTU/lb·°F): 0.21 for sand/gravel, 0.25 for clay, 0.35 for grain.

Inlet Feed Moisture (% wt):

Target Outlet Moisture (% wt):

Operating Temperatures & Thermal Losses

Inlet Gas Temp Tg,in (°F):

Exhaust Gas Temp Tg,out (°F):

Inlet Feed Temp Ts,in (°F):

Discharge Solids Temp Ts,out (°F):

Shell Radiation & Convection Heat Loss (%):

Heat & Mass Balance Results

Water Evaporation Rate

-- lb/hr

-- GPM water evaporated

Total Burner Duty

-- MMBTU/h

-- kW thermal

Dried Output Rate

-- tons/hr

-- lb/hr product

Specific Heat Consumption: -- BTU / lb H2O

Natural Gas Fuel Flow: -- SCFH (-- therms/h)

Exhaust Airflow: -- SCFM

Exhaust gas temperature must remain comfortably above the acid and moisture dew point (typically 170°F - 210°F) to prevent baghouse mudding and severe corrosion.

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Frequently Asked Questions

What is a typical specific energy consumption for industrial rotary dryers?

Well-insulated direct-fired rotary drum dryers with internal flights operate between 1,400 and 1,800 BTU per pound of evaporated water (roughly 60% to 75% thermal efficiency). Poorly insulated drums or high exhaust temperature systems can consume 2,200 to 3,000 BTU/lb.

Why are internal lifter flights essential in a rotary drum?

Lifter flights scoop up granular material from the bottom of the rotating shell and shower it in a continuous cascading curtain through the cross-flowing hot gas stream. This maximizes gas-to-solid contact surface area and dramatically accelerates heat transfer.

How is exhaust gas condensation prevented in baghouse dust collectors?

Direct-fired dryer exhaust contains substantial moisture from combustion and water evaporation. If exhaust gas drops below its water dew point (typically 150°F-170°F), moisture condenses into liquid droplets, blinding baghouse fabric filters with wet mud and generating acidic sulfurous corrosion.