1. Background There have been several problems with the absorber internals in project 186. The internals delivered by Sulzer has been modified. There are still remaining problems with the bubble cap section. 2. Observed bubble cap problems . “Vapour cross channelling”. Liquid drops have been observed flying horizontally (not vertically as it should) across the bubble cap tray. . Accumulation of liquid on the trays. . Periodic flooding through the down comer seal pan. . High gas pressure drops.