Partial Oxidation Reformer
Producing hydrogen for the decentral supply of stationary fuel cell systems can be made by different reforming processes. One among them is the exothermal partial oxidation. Under addition of water the gaseous or liquid fossil fuel is partially oxidated with oxygen or air to a syngas consisting mainly of H2 and CO which can be used in high temperature fuel cells after gas cleaning directly. For the use in medium- or low-temperature fuel cells a CO-Shift and CO2-cleaning is necessary.
To investigate the formation of soot during the reformation of liquid hydrocarbons a partial oxidation test rig was built up at the department of Energy Plant Technology. The main influence parameters studied are the temperature, the pressure, the stochiometry, the residence time and the water-carbon ratio H2O/C.
Experimental setup
The test rig consists of the following 5 main subareas:
- Partial oxidation reactor
- Air supply section
- Feed supply section
- Sample drawing with soot filter
- Burn out section
The schematic structure of the test rig can be seen in figure 1:
The reactor made of fireproof concrete can be regarded as the heart of the partial oxidation reformer test rig (see figure 2). The air heated electrically by six Kanthal heating-elements up to 1400°C and the water/diesel-mixture heated up to 450°C in a tube furnace are mixed in the reactor and undergo a chemical reaction.
A part of the resulting reaction products is led into the oil-cooled, vertical adjustable sample probe and gets diluted with nitrogen. Right above the sampling probe the soot filters are installed that are connected to an electrically heated hose leading the filtered flue gases to the gas analyzers. The soot measurement is made gravimetrically.
The main part of the exhaust gases mainly consisting of H2, CO and N2 have to be after treated in a burn out section. For this reason the exhaust piping is connected to a standard natural gas burner.
Figure 2: POX-reactor