Energetische und sicherheitstechnische Untersuchungen der induktiven Erwärmung von Festbettreaktoren mit kohlenstoffhaltigen und ferromagnetischen Suszeptormaterialien
Research output: Thesis › Doctoral Thesis
The inductive heating of chemical reactors facilitates innovative applications of thermochemical processes, through the much higher power density than with conventional heating methods and the possibility of reducing and / or oxidizing gaseous reaction conditions. The continuously adjustable, inductive heating is carrie out with no material contact and without the use of a fuel. This brings many advantages to the field of low and high temperature pyrolysis. In this respect not only the optimal design of the reactor and inductor is of crucial importance, but also the electrical operation and the choice of the inductively heated material. This thesis shows that optimum heating rates can be achieved for reducing reaction conditions using graphite as a susceptor. Graphite allows homogeneous heating throughout the reactor bed. Thermal image recordings of graphite parts with large geometrical dimensions in relation to the inductor diameter, visualize a low temperature gradient. With ferromagnetic materials it could be proved that the optimal geometric arrangement has a great influence on the efficiency of the heating. Increasing the temperature of ferromagnetic materials is also possible above the Curie temperature. However, in the high temperature range siginificant material losses and thermal stresses in the material have to be considered due to the oxidation processes of susceptors. The large magnetic fields of inductive heating are a safety risk because these fields are technically not completely shieldable. Therefore, the safety distance is the only reasonable safety possibility. The measurements of the fields showed for the first time that the attenuation of the electromagnetic fields is greater than the reduction according to the quadratic law of distance. For the pilot plant at the HTL Dornbirn with 15 kW of electrical power, the safety distance amounts to four meters. The excellent results of inductive heating in efficiency considerations and the new findings regarding this heating method of conductive materials, with particularly good results in the range of heating processes, that means in the run-up phase, confirm its use in the field of temporarily fluctuating power overproduction phases of the electrical supply network caused by the increasing application of renewable energy for power production.
|Translated title of the contribution||Energetic and safety investigations of inductive heating of fixed bed reactors with carbonaceous and ferromagnetic susceptor materials|
|Publication status||Published - 2019|