How to use the drying and incineration heat demand calculator
When sizing a waste incinerator or an industrial dryer, the first number you need is the hourly heat demand. Most of the energy goes into boiling off water rather than heating the solids, so the moisture content drives burner selection far more than the throughput does. Enter the wet feed rate, the initial and final moisture, the feed temperature and the exhaust temperature, and you get the evaporation rate, the net heat demand and the gross heat input after efficiency.
The calculation has three parts. Sensible heat brings the feed up to 212°F using 0.25 BTU/lb·°F for dry solids and 1.0 BTU/lb·°F for water. Latent heat evaporates the water at 970 BTU/lb. Superheat raises the resulting vapor from 212°F to the exhaust temperature at 0.45 BTU/lb·°F.
The heat per pound of water is a quick benchmark for equipment condition. Typical industrial dryers land between 1,400 and 2,000 BTU/lb of water evaporated; a much higher number usually points to poor insulation or excessive exhaust loss. Radiation losses and the heat carried out with the product belong in the efficiency figure. Fuel consumption also depends on fuel heating value and combustion air preheat, so have a mechanical engineer or the equipment vendor confirm the final selection.
Frequently asked questions
This tool uses wet basis, meaning water weight divided by total wet weight. If you only have dry basis values, convert with wet basis = dry basis ÷ (1 + dry basis) before entering them.
Direct-fired rotary dryers usually run 60-75%, indirect-heated dryers 50-65%, and incinerators with heat recovery 70-85%. Older equipment with heavy radiation and stack losses should be assumed lower to stay on the safe side.