clinkers vs. ash... the quality of home heating fuel

[lass442]

After reading a broad variety of posts from pellet users, and having a couple of months experience with burning PA pellets and New England Wood pellets myself I have to ask if there is a pellet manufacturer in the New England area who consistently puts out pellet fuel that does not create clinkers or excessive ash and produces good heat. I've read the recent post regarding Pennington and see that there is some inconsistency in the reviews, but many people like them. While I understand that each plant may or may not have decent quality control, I'm still paying in the upper hundreds to heat my home and would like to lock on to a supply of efficient and reliable fuel. I'm trying not to play Russian Roulette with my fuel bill next year.
NEWP give us clinkers, and PA pellets give us a dirty stove (ash, like you would not believe!) Both give reasonable heat (PA pellets seem to be winning by a nose), and either way, the stove needs to be cleaned every 3 days. The honeymoon's over... I'd like to stretch my burn time to 4 or 5 days and have no clinkers and minimal ash. ( You're thinking "wouldn't we all!?" ) Seems to me we should be able to do this with good quality fuel.

I hate to say that regulations in the pellet industry would help. It would, in a way, but it would also inevitably drive up cost to the consumer. As it stands, the wood pellet industry is primarily self regulated. Increasing labeling requirements, mandates on what types of "biomass" are acceptable for home heating fuel are all things that consumers can ask for, and would be reasonable to expect of manufacturers. I would rather buy a product that tells me on the package exactly what I'm getting, even if it tells me that I might be getting extraneous ingredients, than buy a product again that says one thing, but after I open and use it, I know it's the other (hardwood blend... burns hot and fast, creates lots of ash= mostly pine... which is ok, accept that labeling reads 'hardwood blend').

I don't like subjective and implied labeling when it comes to my home heating fuel, especially when I'm buying it by the ton @ almost $300 per. We used to buy cordwood, and a cord had a legal measurement, and you knew when you stacked it that it measured up and that it was what you bought ( oak or pine ). I only expect the same degree of integrity in my pellet fuel. It's not a health related concern at all, it's a value ( quality for cost ) issue.

SO, my question remains; is there anybody out there who's found a pellet that can claim consistency in quality, heat output & efficiency (clean-burning) over more than one full heating season? If so, NAME THAT PELLET!

Thanks.... Lass

 

[Revig]

As I stated in another post, I've had exceptional luck with either the Atlas or Bear Mountain Pellets, but as always seems, these products rarely leave the Northwest region. Check them out - www.atlaspellets.com or www.bmfp.com .

 

[alexei27]

I wonder if clinkers aren't a product of the stove as much as they are of the pellets. I use the highly sought after Lignetics....and get a clinker every few days with my SHP-55. Two friends of mine have the same stove...both use different pellets...and they get a clinker every few days as well.

 

[MCPO]

I think it`s the carbon buildup in the wood itself and ya just gotta live with it. Some pellets might have more and some stoves probably handle it better than others.
I used to get it in my oil catalytic stove too. Every two months I`d have to shut it down and scrape the burn pot.

 

[sammypoodle]

I have used 3 different pellets in my Hudson River. I purchased 5 tons of LG pellets. Very little fines,burns fine. they seem to have alot of ash. Sort of seems very "fluffy". This cause a clean of every 2 -3 days max . The burn pots gets dirty. Burn temp on setting 1 ,low is 197 degrees. Pennigtons, alot more fines, consistant in size, less ash can go a little longer. Blazer pellets, burn real hot. Setting 1, 220 degrees. Very dirty with fines. But after burning 4 bags I could have gone maybe 5 - 6 days without cleaning. The burn pot was still clean. I had a decent amout of ash but since the burn pot was still clean, my "burn" time before cleaning could have maybe gone a week. Since I start cleaning my pellets the burn seems to be much better. Not sure why but this stove does not like the fines. Not to mention the auger is very quite now.Just a thought......

 

[imacman]

I wonder if clinkers aren't a product of the stove as much as they are of the pellets. I use the highly sought after Lignetics....and get a clinker every few days with my SHP-55.....

I think it's mainly an issue with not enough burn air to keep the firepot clean. I found that I got a few small clinkers regardless what pellets I burned, but since I have opened the air control a little more, I haven't had any....the air holes are open and all the excess ash blows out.

 

[MCPO]

I wonder if clinkers aren't a product of the stove as much as they are of the pellets. I use the highly sought after Lignetics....and get a clinker every few days with my SHP-55.....

I think it's mainly an issue with not enough burn air to keep the firepot clean. I found that I got a few small clinkers regardless what pellets I burned, but since I have opened the air control a little more, I haven't had any....the air holes are open and all the excess ash blows out.

I think a balance has to be found with each stove efficiency design regarding air and clinker buildup. Some being better than others, obviously.
I would think too much air could mean more heat going out the exhaust and not enough means poor flame / unburned pellets, smoke, efficiency loss and clinker buildup.
I scrape only every other day but the buildup is like semi hard but gets powderized easily when scraped off.
Real hard clinkers must to be a problem and a PIA .

 

[Kadnohr]

Hmmmm. Very interesting read.
I am on all the blogs I can find that mention Pa pellets.
You see I am the sales girl.
I understand all of your comments and would like you all to know
all of the facts. Regulations boy you have no idea!
We are testing all the time. By the way the testing fees are insane to say the least.
We are working very hard here to ship out a quality product every day.
I appreciate all of your input. We are not a huge company.
But we pride ourselves in customer service.
I also burn pellets and have burnt many brands.
I have my favorites just like you.

 

[cac4]

The only reason I know what a "clinker" is, is because I read about it here. Burning my Harman accentra for the last 2 months...4 different brands of pellets, I have yet to see anything like what is described. I keep scraping the burn pot, because you people keep telling me to...but there isn't much of anything there to scrape; sometimes, there's a little bit of carbon...very thin...but thats it. From what I've read about what clinkers are, and how they are formed, it seems that its due to ash not being removed from the fire, and as its left to continuously bake, it solidifies. Seems (again, from what I read) that most stoves rely on air movement to remove ash from the fire, and that is subject to so many variables and manual settings, its "hit or miss" as to whether it gets removed or not. With the bottom-feed system, it can't "not" be removed; the same mechanism that is moving pellets IN to the fire, is also moving spent ash OUT, like a conveyor belt. To blame the pellets? well...I suppose, more or different ash constancy/content would affect the stove's ability to dispense with the ash, but as a natural product, I don't see how any manufacturer can guarantee 100% consistent product; same with anything that is "grown" and not "made". It only makes sense that to reduce or eliminate this problem, one has to employ a more reliable ash removal process...which is a fault with the stove, and not the fuel.

 

[Gumby1]

The cleanest and hotest pellet I have used to date are the Barefoot pellets. Clean hot and very little ash :coolsmile:

 

[crausch]

I agree with cac4:

Harman stoves handle the burn automatically and handle the ash well aslo (if maintained). I have yet to have a clinker in my Harman either. Another point that is correct is that minerals in the wood fiber that contribute to clinkering cannot be controlled by the Pellet plants. Unless they control the life cycle of the trees that are used for the pellets. Even then, the environment (mother nature) still is a contributer which is out of the hands of pellet manufacturers. Until technology improves in the manufacturing and in the stoves, its just part of wood pellet burning I guess.

 

[SmokeyTheBear]

I agree with cac4:

Harman stoves handle the burn automatically and handle the ash well aslo (if maintained). I have yet to have a clinker in my Harman either. Another point that is correct is that minerals in the wood fiber that contribute to clinkering cannot be controlled by the Pellet plants. Unless they control the life cycle of the trees that are used for the pellets. Even then, the environment (mother nature) still is a contributer which is out of the hands of pellet manufacturers. Until technology improves in the manufacturing and in the stoves, its just part of wood pellet burning I guess.

The plants can control the clinkering to a degree, they need to produce low ash low moisture pellets.

The stoves can control it to a degree as well, the ash needs to exit the fire pot before any clinkers get to the point they can't exit the fire pot.

Fire pot design can assist or hurt this as can anything that keeps putting ejected ash back into the fire pot.

Combustion blowers are in the loop as is keeping the air path clean.

Extra holes in the stoves fire box other than those that bring air to the pellet pile or pellets to the fire aren't really helping.

What the pellet plants really can't control is the presence of carbon in wood, funny that.

 

[sydney1963]

I have never had a clinker (very hard black chunk) from what I can tell from all the posts. I do have however some pumice like masses that break apart very easily. This is not a clinker. Anyone have a different idea on what a clinker is or maybe a picture of one?

 

[mark d fellows]

I agree with cac4:

Harman stoves handle the burn automatically and handle the ash well aslo (if maintained). I have yet to have a clinker in my Harman either. Another point that is correct is that minerals in the wood fiber that contribute to clinkering cannot be controlled by the Pellet plants. Unless they control the life cycle of the trees that are used for the pellets. Even then, the environment (mother nature) still is a contributer which is out of the hands of pellet manufacturers. Until technology improves in the manufacturing and in the stoves, its just part of wood pellet burning I guess.

Whoa, either I don't know what clinkers are, or I get them all the time with every brand of pellet I use.

We are talking about hard, brittle, carbon like deposits that are stuck to the fire pot and I have to use the scraper provided with the stove or the 16 inch pry bar I bought from Sears to jar them loose, right?

Is it that my stove combustion fan isn't set up properly? Low/High draft? I would hate to have them come out for that. The stove seems to burn just fine. I don't go through a lot of pellets, and it heats my house very well.

Of course, my house is only 1000 Square feet and I keep one of the upstairs room doors closed.

Mark

 

[SmokeyTheBear]

I have never had a clinker (very hard black chunk) from what I can tell from all the posts. I do have however some pumice like masses that break apart very easily. This is not a clinker. Anyone have a different idea on what a clinker is or maybe a picture of one?

Here is a clinker.

 

[sydney1963]

Smokey,

Does that break apart easily or is it hard almost rock like?

 

[SmokeyTheBear]

It breaks apart if you take a persuasion device to it, say a hammer, or stomp on it a few times on a hard surface. Clinkers start out small and fragile then if left alone they grow and get stronger. I can manufacture them quite easily (well I could until Monday, it takes longer now that I have a new combustion fan and most of the ash exits the burn pot rather well).

That white crusty stuff you see on the burn pot sides, etc.. is salt deposits (various mineral salts) and those can also sinter. Your clumps of "pumice" that are easily broken is also a clinker it is just not as fully formed.

 

[sydney1963]

So......it seems to me, if you're not scooping out your burn pot 1 or 2 times daily, you will eventually get a clinker. Hahuh. Caught ya.

 

[sparkydog00]

The only reason I know what a "clinker" is, is because I read about it here. Burning my Harman accentra for the last 2 months...4 different brands of pellets, I have yet to see anything like what is described. I keep scraping the burn pot, because you people keep telling me to...but there isn't much of anything there to scrape; sometimes, there's a little bit of carbon...very thin...but thats it. From what I've read about what clinkers are, and how they are formed, it seems that its due to ash not being removed from the fire, and as its left to continuously bake, it solidifies. Seems (again, from what I read) that most stoves rely on air movement to remove ash from the fire, and that is subject to so many variables and manual settings, its "hit or miss" as to whether it gets removed or not. With the bottom-feed system, it can't "not" be removed; the same mechanism that is moving pellets IN to the fire, is also moving spent ash OUT, like a conveyor belt. To blame the pellets? well...I suppose, more or different ash constancy/content would affect the stove's ability to dispense with the ash, but as a natural product, I don't see how any manufacturer can guarantee 100% consistent product; same with anything that is "grown" and not "made". It only makes sense that to reduce or eliminate this problem, one has to employ a more reliable ash removal process...which is a fault with the stove, and not the fuel.

I too have a Harmen...you can get clinkers...you just haven't burned the right clinker making pellet. Clinkers are formed by minerals that go un-burnt in the burning process. They just sit in the bottom of the burn pot and liquify due to hi heat. Eventually they will form together and come out of the pot...or harden on the bottom of the pot. Turn off your stove and let it cool. Run your hand down the burn pot. It should be smooth. It probably isn't...you need to chip that crap out of there. that is clinkers as well.
Just my 2 cents!

 

[SmokeyTheBear]

Actually Sydney if I stopped burning crud pellets I could easily go three or more days without playing the game even on the old blower etc. Right now I'm into day 2 without any clinker sign yet. You should see the pile of ejected ash I have with my new combustion blower. 35 bags left.

I was popping the clump in my burn pot once a day on heat levels below 3 and twice a day above 2 so you haven't caught me. Besides the manual says check the pot daily.

Oh, and I do it while the stove runs.

Edited to add remark about ejected ash.

 

[Tolyn Ironhand]

I have a Harmon XXV stove. Last year I burned a pallet (60 bags) and never got any clinkers. Also I only had to empty my ash pan once at the end of the year! Those were Awesome pellets! This year I had to get a different brand because my supplier didn't sell the good ones any more. (They were America's best pellets by BMFP) This year we are burning Vally Forest which is a local company which is cool. But yeah....not so much.

 

[mark d fellows]

I get these brittle black things stuck to the firepot. From what I read in the manual they are clinkers. Some times they glow orange until they expend all of the fuel and turn black. They look like Lava while they are glowing. From what I read, that is the definition of Clinker. It happens when all the fuel doesn't burn properly and melts together to form them.

I guess I was always wrong.

I scrape my burn pot twice daily, and always have something hard to chisel off at least once a day. By chisel off, I mean ram with the prybar or cleaning tool.

 

[crausch]

Here is what I have been going by. I pulled this information from another web site and held onto it, but cannot remember where I copied it from so I apologize to the author for not being able to give credit.

Clinkers! What are they? / Why do they form?
This term refers to the formation of lava-like pieces of rock in the burn pot of your pellet stove. Clinkers can look like small or large pieces of lava rock. Clinkers can take the shape of the burn pot and actually form air passageways that cause the clinker to look like a honeycomb-type rock formation.

Minerals and salts are absorbed from the soil through the trees root system. When wood waste from the processing of trees into lumber is turned into pellet fuel, these inert minerals and salts remain entrenched in the wood fiber. When these non-combustibles are exposed to the high burning temperatures of the pellet burning appliance, they melt and form together. This process is also known as ash fusion.

The temperature at which non-combustibles liquefy and form together is referred to as the ash fusion temperature. Depending on the type of minerals and salts contained in wood fibers, this temperature can range from 1100 degrees to 2400 degrees Fahrenheit. Recently the industry has observed that several brands of pellet fuel have a salt and mineral composition that enables ash fusion to occur at lower temperatures, causing severe clinkering. Another side effect of fuels that have higher salt content is the creation of a corrosive atmosphere in the burn chamber, reducing the life expectancy and effectiveness of pellet stoves. If you are dealing strictly with ash fusion, the greatest problem is that you must remove the clinker from the burn pot with a pair of tongs to prevent a reduction in burn efficiency.

Some people relate ash fusion to pellet fuel being "dirty" or containing "dirt."
Nothing could be closer, yet further from the truth!
Yes, minerals and salts are commonly called dirt, but these are inside the wood fiber itself and no fuel manufacturer is capable of removing silicates (minerals and salts) from inside the wood fibers. This should not be confused with scooping up dirt along with raw materials in the manufacturing process, which if allowed to occur will cause massive clinkering

 

[SmokeyTheBear]

.... Yes, minerals and salts are commonly called dirt, but these are inside the wood fiber itself and no fuel manufacturer is capable of removing silicates (minerals and salts) from inside the wood fibers. This should not be confused with scooping up dirt along with raw materials in the manufacturing process, which if allowed to occur will cause massive clinkering

A few things codebum, most salts aren't silicates, the primary clinker formation is caused by the carbon (from that charcoal that is formed by the burning of wood) and silicates in the ash, the salts can contribute but not likely at the temperatures encountered, it also requires moisture. The salts are more likely to form a thin crusty layer on the surfaces of the fire pot liner.

One of the things that I'd also be concerned about is the possible effect of any binder material.

Most silicates in wood come from the bark so step one would be not to use bark in making pellets (this means, no at source wood chipping of slash, on site chipping of non debarked logs is a nonstarter, and the use of slabs containing bark from saw mills must be avoided) and the second step would be to reduce the moisture level of the pellet.

I've burned 4 different brands of pellets this year and while it produced plenty of ash the only one that did not produce any clinkers (I might not have burned enough to notice them) was the Freedom Fuel I got at one of the local pellet moisturizers, after them it was Fireside Ultras, then Natures Heat. All three brands produced far less ash and clinkers than my late July batch of you know what.

Oh the process is called sintering and it is actually used to make useful products.

Be warned there are weasel words (primary, most, might, etc ...) above.