Hydrokattilointi

Hydrokattilointi is a Finnish term referring to hydrothermal processing conducted in closed, water-filled vessels where heat is transferred to a reaction mixture primarily through steam or hot water. The process relies on pressure to keep water in liquid form at temperatures above 100°C, enabling higher reaction temperatures and faster heat transfer than open-boiling methods.

Equipment and operation: Hydrokattilointi is typically performed in reactors resembling autoclaves or boiler-based kettles, designed to withstand elevated pressures. Materials of construction depend on the chemistry, with stainless steel or alloy linings common. Heating is achieved by steam or hot water circulated around the vessel, with temperature and pressure controlled through valves and sensors. The residence time and mixing conditions are adjusted to promote the desired transformation, such as hydrolysis, extraction, or sterilization.

Applications: In Finnish industry, hydrokattilointi is used for biomass pretreatment and extraction of valuable compounds, food processing sterilization, and chemical production where hydrothermal conditions favor specific reactions. It offers efficient heat transfer and can facilitate reactions that require water as a solvent at elevated temperatures.

Advantages and limitations: The method provides rapid heating, uniform temperature distribution, and the ability to operate at temperatures above 100°C. Drawbacks include high capital and operating costs, safety risks from high-pressure systems, and material compatibility concerns with aggressive reagents and condensate.

See also: hydrothermal processing, autoclave, hydrolysis.