Boiler Operations

[BLACKJACK75]

Hi All
Would want to know the effects of running a boiler below the design temp ie 10 bar guage at 182C INSTEAD OF 189c WHICH IS DESIGNED TEMP

 

[InspectorJim]

I have seen problems on some high pressure boilers when they ran in low-fire most of the time. The problem comes when stack temperatures do not exceed the dew point, causing lots of condensation of the fireside.

Also, have seen some people lower the pressure on a boiler and therefore lower safety valve setting(s). At the lower pressure, they had to increase size of SV or add additional relieving capacity to the boiler.

 

[JohnGP]

Without knowing any detail relating to the boiler you are referring to, at first glance I can't see much of a problem really. A temperature of 189C at 10Barg would suggest that the boiler is operating with some superheat - is that the case? If not superheated, then the 189C design temperature could be just to allow for the 10% pressure accumulation allowed when blowing off through the safety valves.

Depending on load conditions, it is common for boilers to operate slightly under design pressure, so 182C operation is feasible. Boilers I have played with have been set to control on pressure anyway, and temperature will follow accordingly.

Cheers,
John