Chemically modified starches (from potatoes, corn, tapioca, wheat, peas, etc.) are used, among other things, in paper production to improve the strength of the paper. The wet process is most commonly used here. The starch is slurried in water, the cationizing agent is added and it reacts. The starch is present as a suspension throughout the entire process until it dries. However, the dry process is more economical, in which the cationizing agent is intensively mixed into the natural starch powder. The etherification reaction is then carried out in a reactor. A second mixer for neutralization is connected downstream of the reactor. The consistency of the starch remains powdery throughout the entire process.
The BHS ring layer mixers HRM and the continuous reactors HTK-T are connected in series for the production of cationized starches. In the first stage, the starch powder (native starch) is intensively and homogeneously mixed with the etherifying agent and caustic soda (catalyst) in the ring layer mixer at peripheral speeds of up to 40 m/s. The etherification reaction takes place downstream in a heated reactor AVA HTK-T. The reaction process takes place continuously with residence times of approx. 1h - 4h. Finally, the starch containing sodium hydroxide is neutralized by adding acid. In this final process step, the best possible mixing of the components is ensured by using an additional AVA HRM ring layer mixer.
In the production of modified starch, the rotary pressure filter is suitable for filtration, washing and drying. Processing takes place continuously in a closed system. This ensures consistently high quality and residual moisture of the end product. The unique pressure-based continuous filtration method of the RPF from BHS facilitates highly efficient and safe production, especially for demanding starch types.