Boiler removal- Herald Hunter.

[AHPP]

3 minutes ago, openspaceman said:

Difficult question; if the stove is properly designed and run then the exhaust should only be warm enough to carry the combustion products up the chimney without any vapours condensing out, if combustion is perfect there is only water vapour to condense. The main thing is that the flame should be able to burn out completely without impinging on any cold surfaces or meeting any cold draught, the heat exchange then takes place after this. This is why modern stoves are refractory lined.

Perceived wisdom is that all the massflow should reach 800C and have a residence time of 1.5 seconds for clean combustion.

 

So you want an insulated burn chamber in which a fuelair mix burns for 1.5 seconds and then collect heat from the flue root or somewhere?

[GarethM]

1 hour ago, AHPP said:

So you want an insulated burn chamber in which a fuel air mix burns for 1.5 seconds and then collect heat from the flue root or somewhere?

It's not really practical in modern stoves as they want the flue temp above the dew point but low enough to not be too hot to damage the twin wall and create a fire risk.

 

Most modern stoves are approx 120c, think that's the figure I've seen somewhere. Plus over time anything higher would damage steel, cast not so much but the flue isn't cast.

Edited February 27 by GarethM

[openspaceman]

1 hour ago, AHPP said:

 

So you want an insulated burn chamber in which a fuelair mix burns for 1.5 seconds and then collect heat from the flue root or somewhere?

Yes but as some heat is conducted through the refractory it then passes through the metal wall to heat the room.

 

On the big industrial wood chip boilers that I worked on the initial off gassing stage was quite cool, about 500C, so as not to damage the feed system and grate ( exhaust gas recirculation was also used to keep things cool). The secondary combustion then took place in a highly insulated tube where all the offgas was burned out at high temperature and then this led to the boiler tubes. The exhaust was then sucked out at a few degrees over 100C. This burned chip at about 35% mc but we often received wetter.