Free tool
How much water you have to evaporate, how much powder you get, how much energy it takes and how much you save by concentrating before drying. No sign-up, no cost.
The particle decides everything: size, shape and final moisture are what the buyer measures in the powder.
Enter your product data. The calculation updates as you type.
Pre-concentration (optional)
All energy figures refer to the water evaporated and are given as useful power in kW. Specific evaporation energy used: 1.23 kW·h/kg in a spray dryer, 0.89 in a flash dryer and 1.00 in a rotary dryer; 0.72, 0.39 and 0.28 kW·h/kg in a falling film evaporator with one, two and three effects, and 0.33 with thermal vapour recompression (TVR). The spray dryer figure is the thermal consumption per kg of water evaporated, with drying air at 250 °C inlet and 100 °C outlet. These are order-of-magnitude estimates: the final figure is settled by product-specific trials and by the thermal design of the machine. The burner or boiler is sized with an efficiency margin on top.
Four questions to frame the decision before you ask for quotations.
With a solids balance. The solids going in are the same ones coming out: solids = feed rate times the solids fraction. The powder produced is that mass of solids divided by one minus the final moisture. The water to evaporate is the difference between what goes in and the powder that comes out. That is exactly what the calculator on this page does.
In a spray dryer the figure is of the order of 1.0 to 1.4 kW·h per kilogram of water evaporated, because air has to be heated and then discarded. In a falling film evaporator the figure drops by half with a single effect and keeps falling as effects or thermal vapour recompression (TVR) are added. That is why it pays to remove in the evaporator all the water the product allows.
Because actual consumption depends on air temperature, heat losses, heat recovery and the product itself. The calculator uses typical industry figures to give a reliable order of magnitude; the final number comes from the engineering of the machine and, where the product demands it, from trials on a real sample.
As far as viscosity, heat sensitivity and pumpability allow. Past a certain point the concentrate becomes hard to atomise and the dryer stops working properly. That limit is different for every product and is one of the key definitions of the project.
If you used the button above, your calculation is already in the message. We send back the reviewed balance and the right machine for it, within 24 business hours and at no cost.