Smokeless fuel - corrosion issue!

Si_Clist

A._Badger said:

...  If it were a general problem with smokeless fuels, other people would have experienced it, surely?  

From what I hear and read, they have, but in any case I'm not suggesting that it's a general problem.  All I know is that it's a problem with one specific make and type of smokeless bought from one specific merchant.  Whether we would have the same issue with it if it came out of the bags bone dry, I know not. 

Whatever, it's no longer a problem here.  We have a new 904 liner, we have all summer to try to dry off the fuel, and we'll see how we go over the winter.  If it looks to me like it's still rotting the system, we'll have to take a loss we can't afford to and flog off the tonne or so that's left to anybody who'll collect it.

ETA - Forgot to mention that after the chimney sweep put a camera up the flue last month, he said to the wife "Have a look at this.  This is why I've been saying you're far better off sticking to wood ..."

FreeBear

Si_Clist said:  If it looks to me like it's still rotting the system, we'll have to take a loss we can't afford to and flog off the tonne or so that's left to anybody who'll collect it.

I had issues with some anthracite nuts that just wouldn't burn in my stove. Spoke to my supplier (CPL Fuels), and they came and took the unused bags back & refunded me. Have a chat with your supplier, and they may do the same.

doningtonphil

A._Badger said:

Si_Clist said:

Ectophile said:

Si_Clist said:

Problem now solved, thank you.

Do tell... how?

Short answer is that we discovered that the liner we believed to be a 904 was actually a 316, and that the smokeless we were sold is a lot higher moisture content than we'd realised.

A new 904 liner goes in tomorrow all being well, and we'll be doing our best to dry out our stock of smokeless between now and October.  It's all bagged, so the plan is to slit the tops of the bags open to let it breathe, and cover the open tops with a tarpaulin when it rains.  Not perfect but it's got to improve matters.

We'll then burn 100% smokeless until it's all gone, then revert to wood. 

As much of an issue as damp could be the sulphur content. You can find the supposed level on the DEFRA website: https://smokecontrol.defra.gov.uk/fuels.php?country=england

I've burned smokeless fuel for over a decade with the current liner and often with wood. So far, no problems. That said,,I have my suspicions about some of the smokeless fuel on sale, as to whether it really is as low in sulphur as is claimed. 

My in laws have recently had a charnwood stove installed and after jsut a few months of using it - with smokeless fuel- they say the glass is 'etched' - from some angles it looks like it is crazed.  Anyway, thye did some research and found it is likely 'low quality' (read: high sulphur) smokeless fuel, the sulphur creates sulphuric acid.
Anyway, I did some research and apparently there is 'smokeless' fuel and 'smokeless-suitable for smoke control areas' fuel.  Only the latter has a requirement for a sulphur content of less than 2%.
We live in rural Scotland so smoke control zones are few and far between so the low sulphur fuel has probably never been on the coal merchants radar.
we find that when we are removing the ash that sometimes there are quite significant yellow deposits.

A._Badger

doningtonphil said:

A._Badger said:

Si_Clist said:

Ectophile said:

Si_Clist said:

Problem now solved, thank you.

Do tell... how?

Short answer is that we discovered that the liner we believed to be a 904 was actually a 316, and that the smokeless we were sold is a lot higher moisture content than we'd realised.

A new 904 liner goes in tomorrow all being well, and we'll be doing our best to dry out our stock of smokeless between now and October.  It's all bagged, so the plan is to slit the tops of the bags open to let it breathe, and cover the open tops with a tarpaulin when it rains.  Not perfect but it's got to improve matters.

We'll then burn 100% smokeless until it's all gone, then revert to wood. 

As much of an issue as damp could be the sulphur content. You can find the supposed level on the DEFRA website: https://smokecontrol.defra.gov.uk/fuels.php?country=england

I've burned smokeless fuel for over a decade with the current liner and often with wood. So far, no problems. That said,,I have my suspicions about some of the smokeless fuel on sale, as to whether it really is as low in sulphur as is claimed. 

My in laws have recently had a charnwood stove installed and after jsut a few months of using it - with smokeless fuel- they say the glass is 'etched' - from some angles it looks like it is crazed.  Anyway, thye did some research and found it is likely 'low quality' (read: high sulphur) smokeless fuel, the sulphur creates sulphuric acid.
Anyway, I did some research and apparently there is 'smokeless' fuel and 'smokeless-suitable for smoke control areas' fuel.  Only the latter has a requirement for a sulphur content of less than 2%.
We live in rural Scotland so smoke control zones are few and far between so the low sulphur fuel has probably never been on the coal merchants radar.
we find that when we are removing the ash that sometimes there are quite significant yellow deposits.

That's interesting, thank you. The only flaw in the theory is that, if I recall my school chemistry lessons,  sulphuric acid doesn't affect glass, does it? I'd be more inclined to wonder if Charnwood (a very reputable maker I understand) had bought a dodgy batch of glass. I would worry about a liner, though, if the fuel I was being offered produced more than 2% sulphur.  

Mickey666

One problem with stoves, regardless of the fuel, is setting them to burn too slowly, sometimes called 'slumbering'.  It's understandable in the sense of trying to use less fuel but it can be counter productive because it means the stove runs cooler, which means it's more likely that corrosive components within the flue gases condense within the flue (or in extreme cases within the stove itself) rather than remain gaseous until they exit the chimney, with inevitable consequences.

In general, it's better to do a reasonably fast burn - though not exceeding the maximum recommended flue temperature (you do have a flue thermometer don't you?) then leave a gap rather than set the stove to 'slumber' away constantly.  Not always easy, I know.  

Hopefully the 904 liner will last a lot longer then the previous 316 liner.  It certainly should do!

Si_Clist

A._Badger said:

... The only flaw in the theory is that, if I recall my school chemistry lessons,  sulphuric acid doesn't affect glass, does it?

No.  If it did, sulphuric acid wouldn't be stored in glass bottles, and it is - at concentrations of up to around 98%!

lohr500

Si_Clist said:

A._Badger said:

... The only flaw in the theory is that, if I recall my school chemistry lessons,  sulphuric acid doesn't affect glass, does it?

No.  If it did, sulphuric acid wouldn't be stored in glass bottles, and it is - at concentrations of up to around 98%!

Except that stove glass is not the same glass as used for bottles and conventional windows.

A._Badger

lohr500 said:

Si_Clist said:

A._Badger said:

... The only flaw in the theory is that, if I recall my school chemistry lessons,  sulphuric acid doesn't affect glass, does it?

No.  If it did, sulphuric acid wouldn't be stored in glass bottles, and it is - at concentrations of up to around 98%!

Except that stove glass is not the same glass as used for bottles and conventional windows.

I would imagine the material used is borosilicate glass, about which Wikipedia says: "Showing an extremely high chemical resistance in corrosive environments. Norm tests for example for acid resistance create extreme conditions and reveal very low impacts on glass".
I'm pretty sure there is something else afoot here.

lohr500

https://www.chiswellfireplaces.com/stove-glass-gone-cloudy/#:~:text=Sulphuric acid is corrosive.,which is a white powder.&text=Modern stoves are fitted with air-wash.
https://www.thestoveyard.com/pages/what-can-i-do-to-stop-my-stove-glass-becoming-cloudy-or-crazed
https://blog.gr8fires.co.uk/2021/04/21/cloudy-stove-glass-why-it-happens-and-how-to-stop-it/
https://www.decorumfireplaces.co.uk/carlton-house-fireplaces-blog/why-cant-i-clean-my-stove-glass

They all seem to suggest that sulphuric acid is a problem. Perhaps they are all perpetuating a myth?

A._Badger

lohr500 said:

https://www.chiswellfireplaces.com/stove-glass-gone-cloudy/#:~:text=Sulphuric acid is corrosive.,which is a white powder.&text=Modern stoves are fitted with air-wash.
https://www.thestoveyard.com/pages/what-can-i-do-to-stop-my-stove-glass-becoming-cloudy-or-crazed
https://blog.gr8fires.co.uk/2021/04/21/cloudy-stove-glass-why-it-happens-and-how-to-stop-it/
https://www.decorumfireplaces.co.uk/carlton-house-fireplaces-blog/why-cant-i-clean-my-stove-glass

They all seem to suggest that sulphuric acid is a problem. Perhaps they are all perpetuating a myth?

Reading their recommendations about running stoves hot, using air washes (where available), avoiding pet coke and so on all make sense and is common (good) advice. On the other hand, authorised smokeless fuel sold in the UK is supposed to produce no more that 2 % sulphur and if you check the DEFRA website you'll see that all the various brands claim to stick to that. Of course, whether they do or not is a moot point. 

Eventually, after about nine years or so pretty hard use the glass on my stove started to show marks which my sweep said were due to heat stresses over time. I've no reason to doubt him. As for the likelihood of stove retailers perpetuating myths, some of the ones I've encountered could have been reincarnated 18th century horse traders, so, yes, I think that's possible, but who knows for certain?