Investigation of the cleaning of egg yolk deposits from tank surfaces using continuous and pulsed flows

This work examined the effects of burst or pulsed flows on the cleaning of tank surfaces soiled by egg yolk, under alkaline conditions, using a single axis rotary spray head. Firstly, four cleaning approaches (continuous flow without pre-wetting, continuous flow with pre-wetting, pulsed flow with a shorter period, pulsed flow with a longer period) were tested on a pilot-scale tank to clean both uncooked and cooked fouling materials. The effects of temperature, flow rate and alkali concentration were investigated. The results show that pulsed flows improve cleaning behavior, where pulsing with a shorter period and higher frequency results in the most deposit removal at the same detergent consumption. The impact of pre-wetting is less significant under the investigated conditions. Some findings are consistent with earlier reports, stating that higher temperature and flow rate improve cleaning by reducing cleaning time. An optimal alkali concentration exists, which is in line with results reported by other researchers when investigating other protein soil types. The economic benefits by using pulsed flow cleaning were discussed. Then, scale-up tests confirmed that the enhancement of cleaning by using pulsed flow with short period and high frequency could also apply in an industry-scale tank.