ACC Cleaning Experiences

[sjamali@vpi-i.com]

May I please ask the members to share their experiences on Air Cooled Condenser Heat exchanger Cleaning. It would be a great learning opportunity for all around us.

1) Frequency of cleaning – How often it is deemed necessary to clean, what triggers you to make decision?
2) Method of cleaning i.e. rail pressure wash or using lance and jet pressure.
3) Is cleaning the ACC on Fan side as effective in conjunction with the rail system?
4) How to you compare before and after results on ACC in a systematic manner.
5) Is there another benchmark for performance improvement on ACC other than back pressure improvement for similar load conditions?
Thanks

[huubhubregtse]

Hi,
I can tell you a lot about ACC cleaning.
In 1993 I developped the first ACC cleaning system for the Rye House ACC in the Uk
this system has been improved over the years and is now used worldwide.
1. the frequency of cleaning is normally once a year. If the ambient is dusty cleaning can be done more often.

2. we use rails and a moving rig. Cleaning is not adviced to be done by hand. The high pressure water beams with a pressure of about 90 bar can damage the fins, therefor the spray angle must be fixed, which is impossible to be done by hand.

3. Cleaning should be done from the outside towards the inside. Most fouling is on the inside bundle surface with a dept of about 50 mm. By cleaning from the outside the fouling is directly washed away in the direction it came from.

4. we often make a small thermal calculation before and after the cleaning. This indicates the effect of the cleaning. A simple way to check the effect of the cleaning is to measure the static pressure in the planum compared to the ambient. The operator can make this measurement on a monthly basis and record the increase of static pressure. From expeience he can that indicate the time cleaning is required.

5. As the performance depends on A. the air flow, which can be reduced by fouling, B. the ambient temperture and C. the steam flow. The performance curves can help to determine the performance. We often make a thermal calculation with a computer model. When the computer model is made, we just fill in the ambient temperature and the steam flow and calculate the back pressure. This can then be compared with the actual back pressure.

I hope this explains the cleaning process.
if you need some more information just send me a mail.

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