When baghouse loading rises noticeably during AFR firing, two things are usually happening at once: the AFR is bringing finer ash into the gas stream than the original fuel mix, and combustion is leaving more unburnt carbon to find its way to the filter. The dust increase is a leading indicator. By the time it shows up as shorter cleaning cycles or higher differential pressure across the bags, media life has already been shortened by a measurable amount, and the next replacement schedule has moved closer.
Why this matters in the afr / alternative fuels
Bag filter media is a consumable that ages with both temperature and loading. Higher-than-design loading means cleaning cycles run more frequently, mechanical fatigue on the media accumulates faster, and the next planned change-out is going to fall earlier than the budget assumed. The incremental cost over a year of high AFR firing can be substantial.
Emissions are the second concern. Loading that rises slowly may stay inside permitted limits during normal operation but step over them during cleaning cycles or upset conditions. Plants running near their permit envelope cannot absorb a quiet AFR-driven shift without consequence. Treating bag loading as a process indicator, not just a maintenance metric, gives the team time to act.