A starch jet cooker is a unique heating device designed specifically for heating high solids starch slurries derived from starches such as potato, wheat, tapioca, rice, and corn.
Starch, in its dry form, is made up of tightly bound, highly branched molecules. In order to be useful as a sweetener (glucose and fructose production), fuel (ethanol production) or thickening agent, the molecules must be opened up by heating them in the presence of water. This is typically accomplished by grinding the starch and mixing with water to create a slurry. The slurry is then heated in a process known as starch hydrolyzation.
While any means of heating the slurry will eventually work, a starch jet cooker is the preferred method for heating, as it offers many advantages over other approaches.
Heat exchangers, the most common means of heating fluids, have a difficult time heating a starch slurry. As the slurry is heated, it immediately begins to thicken. The thick starch tends to coat the heat exchanger walls. This coating reduces the effectiveness of the heat transfer and leads to plugging of the heat exchanger and inconsistent starch cookout. High maintenance costs and wasted starch product is a result.
Another approach to heating the starch is to use direct steam injection into a tank or other vessel. The steam is injected through nozzles, jets, or other spargers to raise the temperature of the slurry and cook the starch. This approach tends to be successful with only very low cook temperatures (<135°F) At higher temperatures, the thickened starch inhibits the condensation of the steam into the gelled starch and usually leads to rough or violent operation, often damaging the equipment and presenting a hazard to operating personnel.
A well-designed starch jet cooker solves all the problems listed above. Steam is continuously injected into the flowing starch slurry through an injector coaxial to a starch condensing tube (see Fig. 1). This starch cooking stage is a critical stage prior to the starch liquefaction stage.
ProSonix Starch Jet Cooker Benefits:
- Because starch and steam are flowing continuously, there is no plugging or fouling of the heating surfaces to retard the heating process.
- Most importantly, the starch slurry is intimately mixed with the steam. This results in rapid and complete starch hydrolyzation and more complete cookout of the starch.
- Starch cook temperatures can be precisely maintained, allowing the process to be fine tuned to the needs of the final starch product. Cook temperatures from 160°F to 300°F (71°C-149°C) are common
- Starch can be cooked at dry solids levels up to 40%. This reduces water use and saves energy by reducing evaporative costs
Contact ProSonix today to learn how a PSX Jet Cooker can improve your starch cooking process.