Clinker - nothing to bad, why!?

[Doing it for the kids]

ive been burning raw chip in a batch boiler with utter ease for 3 months, now suddenly I’m getting caps over the bottom duct daily.

The chip is too dry @10% I guess but the fan is right down now so I’m not convinced that’s the root cause.

I have little control of the chip quality, I’m still burning the same batch though. It’s coming from the same teams locally.

I can’t see any rubbish in the sample, there is the odd stone though.

I suspect if I blend the chip with some wetter stuff that may help but I’m puzzled why it’s suddenly got bad. Im getting about 800 kWh (at meter) from 1,8m2

My understanding in clinker is formed at about 1200 degrees. It’s formed from silica which comes from bark and poor quality wood.

Any advice greatfully recieved!

 

[rollestonpark]

I'm not familiar with these batch boilers if I'm honest, however:
In a standard type wood chip boiler, you have the the primary air that comes from below the grate and the secondary air that comes from above.
You tend to use a lot less primary with drier fuels and more secondary.
Also if you run a lot of air in general with very dry fuels it can burn too hot and form large hard lumps (clinker type stuff your getting)

I personally would try reducing the total air volume being blown in.
If you have primary and secondary air systems, reduce the total but also reduce primary and use more secondary.
Chris

 

[Doing it for the kids]

Thank you.

There’s an 8 inch square tube that sits on the deck and a ‘hammer head shark head’ from above. I’m getting a charming cap over the square tube that I never got before.
Literally nothing has changed other than this. Wondering if the air duct splitter has moved - I will investigate!