At SITA’s Isle of Man energy from waste plant (EFW), an Air Cooled Condenser (ACC) is used to condensate steam back into the generating process. Over the course of generation, dirt, grease and grime affects the ACC’s efficiency, which in turn increases site expenditure. Historically HP Jetting was employed to clean these tube banks, but concerns over safety and damage to tube fins led to a trial of RICO’s ACC deep clean service. RICO’s task was to clean the ACC improving cleanliness throughout all tube banks, with no tube fin damage, and overall gains in ACC performance.
RICO’s safe chemical clean of SITA’s ACC included 2 stages:
1. Application of Safe Degreasing Chemical: At a dilution of 50:1, the degreasing chemical was mixed with water, with 1000 litres of mixed solution being spread over 2 ACC sections at a time. The solution was left to soak through the 4 tube banks lifting grease as it settled.
|Figure 1. Chemical Application
|2. Deep Water Clean: Once the degreasing chemical had been left to settle and work on the dirt and grime, a CAT booster pump was used to wash down the treated sections. Pushing out over 35 gallons of low pressure water per minute, the pumps provided a deep cleaning affect, washing through all of the tube banks, and removing both the degreasing chemical and lifted grease and fouling (Figure 1).
Feedback & Analysis
During the cleaning process there were visual indicators that dirt and grease was successfully being removed from the tube banks and out of the ACC system. See Figure 2. showing the cleaned tube banks from underneath.
In addition to visual indicators, post clean analysis provided by SITA concluded that the deep clean had increased efficiency, and improved system longevity, leading to financial gains in the long term. These factors were indicated by:
- Increase in MWh output
- Lower Back Pressure /Lower stress on LP blades
- Decrease in fan speed requirement
- Higher Steam flow
Figure 2: Cleaned Tube Banks