When a hot potassium carbonate CO₂ absorber begins crystallizing, investigate local cold spots, solution concentration, shutdown cooling, branch-line temperature, distributor openings, and startup solids transport before changing the packing. Open packing can improve tolerance, but temperature and solubility control remain the root solution.

When a hydrogen-peroxide-based scrubber consumes far more reagent than the target-gas mass balance predicts, investigate peroxide decomposition caused by temperature, catalytic contaminants, metal ions, pH, storage conditions, and circulation-loop materials. More packing cannot compensate for oxidant that decomposes before it reacts with the contaminant.

When scrubber inlet/outlet testing shows good removal but the final stack remains high, inspect bypass ducts, dampers, isolation seals, branch flow, and sampling locations. Untreated bypass leakage can dominate overall plant emissions, and adding packing or liquid circulation will not correct that parallel gas path.

When one of two parallel scrubbers is offline, common fans and headers can drive reverse gas flow through the idle tower unless suitable isolation is provided. Check pressure balance, damper leakage, flow direction, drainage, maintenance isolation, and restart condition rather than assuming a stopped pump or fan means zero flow.

When scrubber removal deteriorates while the pump still runs, check strainer or filter differential pressure, actual circulation flow, pump suction condition, and distributor pressure. A loaded strainer can reduce irrigation without producing a high tower pressure-drop alarm, while bypassing it can shift solids into the distributor.