Catalytic oxidation of volatile organic compounds is evaluated on three numbers: light-off temperature (T50/T90), full conversion stability and byproduct profile. A fixed-bed test rig produces these numbers honestly only when gas preparation and flow discipline are right.
VOC feed streams are generated by bubbling, permeation or syringe pumps into a carrier. Each method drifts differently, calibrate the feed concentration before every campaign. Moisture matters: real exhausts are wet, and water competes for active sites, so include a humidity condition that reflects the application.
Fix GHSV and state it with the bed volume basis. Keep the bed short and isothermal, long beds develop axial profiles that blur light-off curves. Dilute feeds keep the reaction heat release from self-heating the bed, which otherwise flattens T50 and flatters the catalyst.
Conversion of the parent VOC is not the end of the story: partial oxidation can produce aldehydes, CO and aerosols. Monitor CO/CO2 and screen for partial-oxidation products with an appropriate method; a catalyst that converts 99% of toluene into benzaldehyde has not solved the problem.
Report T50/T90 from a slow temperature ramp, conversion at fixed temperature over time (deactivation), and the moisture condition. Water tolerance often separates laboratory stars from deployable catalysts.
See purification equipment and catalysis solutions for VOC evaluation configurations.
