Ultrasonic particle production

The pilot reactor in Hanau-Wolfgang (Germany) produces custom-tailored particles with special properties. The properties are produced by selective regulation of the morphogenesis/aggregation capacity of the particles during the production process. The special features of this new process include the extremely high heating rate of the gas mixture, which is achieved by system of ultrasonic pulses, and gas-dynamic quenching of the gas particle stream with the aid of ultrasonic technology.

The particles are generated in a specially constructed ultrasonic reactor using a carefully regulated process based on gas-dynamic effects. In the pilot plant, the energy required for this is provided by streaming the gas at temperatures of up to 1,500 °C and up to 10 bar overpressure. After it has passed through the first of two ultrasonic nozzles, a chemical reaction is initiated by a gas-dynamic shock. The chemical reaction results in the formation of particles. At times, the flow rate is more than double the speed of sound. By choosing suitable parameters, the reaction conditions in the reactor can remain homogeneous and stable up to the quenching step, providing ideal conditions for fundamental investigation of how the particles are formed.

The process is halted abruptly by quenching in the second nozzle at the end of the reaction chamber. The particles can then be filtered out for further use. The particle size can be modified via parameters such as temperature and reaction time. Yields of up to three kilograms powder per hour can be obtained in the reactor.