Hot Filling of Boiler

At suspected tube failure temperature?,,just guessing.

Where did you notice the 300deg temp --- Is it Flue gas temp or metal temps. and at what location--whether at Platen SH, FSH , bank tubes or the drum metal temp?

If the drum metal temp was 300deg, It cant be filled with cold water , as it will cause heavy hammering and temp differential stress. But if it is PSH or FSH at 300deg And if the drum temp is normal, we can presume that water wall tubes will be at lesser temp and we can fill it up with cold DM water.

Ussually, we fill the boiler with cold water , if the drum metal temp is 100--120 deg or less.

dear sir ,

thank u very much for your reply

300 deg temperature mentioned was metal temp of FSH is there any provision to fill the boiler with hot water ?

I think If your FSH metal temp is 300deg, then your drum metal temp will be quite less [ as in our case 150--200 deg less]. So As per my estimation, It may be Okay to feed cold water. At this FSH temp you can avoid filling SH tubes, as it may cause heavy hammering in SH coils, which in turn can bend the coils. Also In both cases, It will be better to feed water slowly, so as to reduce hammering and thermal stresses.

For filling with hot water, We have only the provision through Deaerator and BFP. And Feed water can be changed by reducing the daerator pressure.

But You may collect other suggestions as well.

You did not say if it was a hotwater or steam boiler or if it was high or low pressure Where does your makeup water feed into the boiler, return loop, condensate, direct ?

Most boilers do not do well if they are filled with cold water when they are in a overheated condition, which is often caused by low water.

In my experience in steam boilers we NEVER put cold water into any hot boiler but water was preheated in feed tank always- the idea is to minimise expansion/contraction - & HOW did the tube fail?- lack of maintenance?.

Is it not okay to feed 35deg water when the drum metal temp is 120deg or less?

What is the temp at which you feed cold water, and you feed from the feed tank.

How is your arrangement of feed tank-- Of what % capacity [ dependingon the boiler tonnage] and how do you supply heat to it and what temp you maintain?

Kindly share the information with us

Dear sir ,

normally we fill water in to boiler when metal temp is below 120 deg . As emergency need we filled one time when FSH metal temp is at 300 deg i know it is wrong .

we have feed tank of capacity350 tons it is being maintained at atm temperature

Hi,

Metal temp. is a very important criteria for boiler filling. If it is a case of hot filling I suggest you to keep temp. mismatch within 75 deg. C and use hot water through deareator heating and boiler feed pump.If drum metal temp. is within 120 deg.C cold filling can be done through water walls. Hope it will work.