SOLREF: Development of an Advanced Solar High-Temperature Reformer

The main target of the EU project SOLREF (solar steam reforming) is to develop a highly efficient and cost effective solar reactor for high-temperature reforming. This was reached by designing a new more compact reformer with innovative solutions. Besides construction solutions in interaction between DLR and HyGear, the layout of the absorber was done at DLR by using simulations tools (HELIOS, SORSIM, VORECO) extended or developed at DLR. First the geometry of the absorber was optimized during an iteration process using the results of a SORSIM simulation runs generating flux density distributions on the absorber. Secondly the final output was used as the input for the VORECO software simulating the reformer regarding mass and heat transfer inside the absorber. The resulting layout data are as follows: • Absorbed power: approx. 400 kWth; up to 500kWth can be possible. • Methane conversion level, overall: 80-90 % • Temperature of the product gas, receiver exit: approx. 900°C • Operating pressure: 15 bars (optimal: 10 bars) • Fluid inlet temperature: approx. 450°C Further, the paper discusses the temperature distribution in the absorber (one-dimensional) and on the absorber surface. Due to the fact that hot spots reduce the catalyst activity significantly and later on lead in the destruction of the absorber material, the absorber will have different mass flow regulations. Experimental experiences from the previous project SOLASYS and actual simulations show, that adapted mass flow regulations will reduce the maximum absorber temperature from 1100°C down to below 1000°C and the temperature differences in and on the absorber from 200-300K down to about 100K or even less.