2 replies to this topic

[wojtar]

Could anyone explain what is back flashing facility for heat exchanger?
I've got such comment that must to answer: "Back flushing facility shall be provided for W-2106".
W-2106 is a vapours condenser cooled with water in tube side.
Thanks in advance for replies.

[cea]

Dear Wojtar-

Firstly, I guess, it is not "back flashing", but "back flushing", what is expected. Please confirm.
It it is so, it is generally related to cooling water, as this is fouling liquid. As you know that performance of heat exchanger is adversly affacted due to fouling. One way is to have periodical mechanical cleaning of tubes (cooling water is generally on tube side). However, this requires shut down of the heat exchanger (in many cases, it is shut down of entire plant).

This periodical cleaning can be prolonged by doing "back flushing". In this, cooling water supply valve is closed, water is allowed to drain from drain valve which is at the upstream of cooling water supply isolation valve near exchanger. Thus, C.W. flows from return header to heat exchanger to drain.

This back flushing causes any suspended particle fouled over tube wall to come out in drain & hence improvement in the performance. However, during this operation, plant load needs to be lowered down, so that process should not get distrubed.

Hope, this has clarified the matter.

Regards,

[wojtar]

Thanks a lot. It seems that it's clear. However, all described above is possible on my installation. Statement "back flushing facility" suggested something more sophisticated.