Development of a heterogeneous catalytic cracking reactor utilizing online mass spectrometry analysis

A laboratory system has been designed, constructed, and validated that reduces the complexity, time required, and data variability associated with catalytic microreactors that require post reaction steps prior to product analysis. In this work, a Varian (Walnut Creek, CA, USA) 3600 GC (gas chromatography) system coupled with a Saturn quadrupole ion trap mass spectrometer was used to perform mass spectral analysis in real-time catalytic cracking reactions. As this was an integrated reactor/analyzer, the GC column was exposed to temperatures beyond the degradation point of the column, and so selective ion storage RF waveform was used to remove the siloxane masses from the spectra. This produced lower detection limits and full scan data for identification. Mass/charge segmentation of the mass spectrometer allowed the complete product identification for electron impact spectra. Hexane was reacted over H-ZSM-5 catalyst for instrument validation. This produced a series of alkanes, alkenes, and aromatics with distributions consistent with that reported for the cracking of hexane.