Design of a rotary kiln for a solar-powered air separation process

Abstract

The aim of the DüSol project is to find a solar-powered process for the production of chemical fertilizers and demonstrate an air separation process for nitrogen production, that meets the purity requirements for the Haber-Bosch process. The focus of this thesis is developing of a 20 kW rotary kiln for the production of nitrogen from air with a purity of less than 10 ppm residual oxygen concentration. In order to achieve this 2 kg redox material is to react with 7.8% of air at 800°C under gas tight conditions. An existing furnace was adapted for this purpose, though the development of a new steel crucible with a support construction, a novel gas supply and release system as well as a temperature measurement system had to be designed. The reactor, mostly made of standard parts, was assembled and tested using a solar simulator. It was shown that the reactor meets the requirements regarding temperature resistance and gas tightness, but the measurement system still has to be improved.