Methane pyrolysis over porous particles

The deposition of carbon from methane pyrolysis on various porous media was investigated at 950-1100 degrees C. 7 Types of unfunctionalized carriers were used, with pore sizes varying between 4 nm and 250 mu m. Carbon deposition over time was measured in a single particle reactor. It was found that the porous samples can exhibit both an induction period as well as a gradual stop in carbon deposition. An induction period was observed for alpha-Al2O3 samples, but not for gamma-Al2O3, SiC and C carriers. Hence, the slow start of the carbon deposition may be caused by substrate material. Furthermore, for all samples, an apparent maximum carbon loading was observed. It was confirmed that this is not caused by pore blockage, as significant surface area remains in these samples at the point of maximum carbon loading. In fact, it was found that fraction of pore volume filled at maximum loading, is a function of the initial pore diameter. The smaller pores fill to a lesser extent than the bigger pores. This maximum achievable carbon fraction was incorporated in a particle model. Using only the fraction of volume filled as a single parameter, the measured loading over time could be described.

Automated summary

The deposition of carbon from methane pyrolysis on various porous media was investigated at high temperatures. Different types of unfunctionalized carriers were used with varying pore sizes. Carbon deposition over time was measured and it was found that the porous samples can display both an induction period and a gradual stop in carbon deposition. The substrate material and initial pore diameter were found to affect the rate and extent of carbon deposition.