Charcoal or something similar?

I am a long time reader, but first time poster. I did a search for this question but I did not really find any results. My apologies if it has been asked before.

First off, my stove is a St Croix Lancaster. It is the older model that was designed for corn (before it was sold as a multi-fuel stove). Last year I burned a wide variety of fuels to find what I liked best. My favorites were cherry pits, standard wood pellets (super premium) and pellets a little brewery around here makes with the discarded brewers grain. I have found corn to be too hit or miss with the moisture content changing varying widely rapidly between sacks. Cherry pits are my favorite as the leave hardly any ash and have about a 200 btu advantage over wood pellets. The problem is my supply of them is hit or miss as I missed my opportunity to buy in bulk early in the season. I got a great deal on 3 tons of energex hardwood's in early fall so I have been burning those.

I have an old drafty brick farm house. I have done everything I can within a reasonable cost to seal it up drafts and add insulation, but there is only so much that can be done cost effectively. When the temperature really drops (teens or below) or it is breezy my stove has a hard time keeping up. I noticed that the cherry pits with a couple extra BTUs seemed to keep the temp in the house up for a little longer and held an extra degree vs the wood pellets.

My questions was, is it a completely horrible idea to mix some small pieces of charcoal (broken from a briquette) into the hopper with the wood pellets for extra heat? At first it seemed like a really stupid idea to me, but the more I think about it, it might not be as ludicrous as I first thought (or it could be! that's why I am asking here). I understand that charcoal produces more carbon monoxide vs dioxide as with wood. However if your seals are in good shape all the gases would be vented right out the exhaust. Of course I also have carbon mono/dioxide detectors in the house as well. Is there any gas burning charcoal produces that may be harmful to the stove itself? Such as coal can produce a very caustic exhaust which can wreak havoc on a stove not designed for it. Also what temperature range would charcoal burn in under negative pressure such as in a pellet stove? I know coal would burn much too hot for the sheet metal and components of a pellet stove, but I have no idea about charcoal.

I wish I had an old stove I could hook up outdoors and experiment with, but I do not have the luxury.

I realize that this may be a really stupid idea, but even if so I prefer to know why it is a bad idea. I just really like knowing the "why" behind things.

Thank you for any input you guys have into this!

peakbagger said:

What you really want is not on the market in the US yet are called orrefied wood pellets. There is one company that makes something close for export http://zilkha.com/zilkha-black-pellets but they seem to have gone quiet of late. Basically they are a super pellet, higher btu content means fewer pellets to lug around and a lot easier to package as they don't absorb moisture.

Activated charcoal is basically overcooked wood, pretty much pure carbon, unfortunately a lot of the btus from the lignin components get driven off in the process. Ideally you want a piece of roasted wood that has had all the moisture driven off but all the volatiles left in it. IF you play it right, the lignin collects on the surface and acts to waterproof wood so it doesn't reabsorb the moisture.

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Thanks peakbagger! That is pretty much what I was envisioning, I just couldn't find a company that produced such a product. It seems that they only sell to power plants etc on huge scales as of now. Regardless I will reach out to them and see if I can get them to send me some to play around with. Maybe they will eventually open up to the home consumer market, but there will probably be an issue with stoves not being approved to burn it etc.

If they can't send me anything I may experiment with some small charcoal pieces mixed in the hopper when the wife isn't home. That is of course unless someone more knowledgeable weighs in with a big issue I haven't thought of. The heat issue is my biggest concern at the moment, I hope it isn't too hot.

Bioburner said:

Pine charcoal is what brought man into the iron age
I made a simple drier to resolve issues with corn moisture.
I don't see where small amounts of charcoal will harm or raise the pot temp very much. Ive gotten enough burnt corn to see a rise in temp but probably because it is easier to light.

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If you dont mind me asking how did you make your corn drier? Do you have pics or anything for it? I wouldn't mind burning more corn if i could ensure a consistently dry supply. The price is right here in central PA as we grow a huge amount of the crop, but being that corn stoves aren't popular around here it is typically only dried to feed levels of moisture content, not burning.

I think i will play around with charcoal. I will update the board with my results

Thanks for the input and knowledge!

doghouse said:

Look up/research "Rice Coal." I know of some who use a 10% mix in their stoves. They claim wondrous results.

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A few years back i had a coal stoker that used rice coal so im pretty familiar with it. I'm not too keen on putting any amount of coal in a pellet stove though. Ive heard way to many horror stories.

Just an update as i had time to try out the charcoal a little bit.

I was at wally world to get wicks for my kero lanterns in case we lose power in this blizzard (23 inches and counting!). While there i decided to pick up a bag of charcoal to test out since i was going to be stuck home anyway. They didnt have natural lump in stock since it is out of season, so i am using classic kingsford ($3.99 for a medium bag).

I first broke up the briquettes into pellet sized pieces and mixed it with the wood pellets on a ratio of approx 5% charcoal. It fed smooth through the auger and burned well. I cant say i noticed much if any more heat however. The next step is to up the ratio of charcoal.

I have been lazy since breaking up the briquettes inti the correct size pieced is a bit of a PITA and messy. I decided to place some charcoal directly into the burn pot while burning on a setting 5 (that is all the way up for a lancaster). there was a noticeable increase in heat.

My overall conclusion is that if mixed at a high enough ratio with the pellets you can absolutely get more heat out of the stove. The two drawbacks are the process of breaking up the briquettes and also the cost. I assume it is not cost effective, but i will run some numbers if i continue to burn it.

Thanks for everyones help!

doghouse said:

Broudy, I know you mentioned that you would never use coal in your pellet stove, but Kingsford uses small amounts of coal in their charcoal briquettes.

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Not that i dont believe you, but do you have a link to anything confirming that? I looked at the msds sheet on their website and it lists the contents of the briquettes as hardwoods, limestone and sodium tetraborate decahydrate. I didnt see anything about coal.

Lake Girl said:

How much of a mess did you make breaking up the briquettes? How did the auger handle it?

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The auger didn't skip a beat and seemed to handle the charcoal just fine. I did make extra sure that no large pieces made their way into the hopper.

Breaking up the charcoal was a mess and a half. My work bench still has black dust everywhere even after i "cleaned" everything. This part was not only messy, but tedious as well. There is a fine line between breaking the briquettes into pieces and pulverizing them into nothing but dust.

I was burning charcoal all day yesterday at a 10-15% mix. I had more heat on the stove and the house stayed about 3 degrees warmer vs other days with the same temp (approx 21 degrees f daytime). I am sure the snow on the roof and drifted up on the house provided extra insulation too. I monitered the stove closely and inspected everything when i shut it down to clean and there are no obvious signs of issues from the extra heat.

Now if only i had a pellet mill to make charcoal pellets.....

I have contacted the company mentioned previously in this threat to no response. I'd love to test out actually charcoal/torrified biomass pellets.

Deezl Smoke said:

Thanks for the update. That is awesome. If you can get the same or greater heat out of less product, then a cost comparison is definitely in order. Thanks again for the update.

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Once i dial in exactly how much i want to use consistently, what type of charcoal etc i will run some numbers. It won't be an exact science but should give a ballpark idea.

NYBurner said:

very cool experiment, look forward to read your results.

Also, why do you not like coal?

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I love coal!....just not in a pellet stove.

The gasses from burning coal are very caustic and can cause all sorts of problems corroding the internals of a pellet stove which will lead to many points of failure.

main issue is coal burns wayyyyyy too hot for a pellet stove. On the majority of pellet stoves burning anything above a minuscule amount of coal absolutely will either melt the steel of the burnpot and/or sidewalls or distort the metal. What can happen even if you dont get a complete melt-through is the metal gets warped enough that the gasket on the door doesn't seal property and there is no way to correctly fix the warped stove.

Lastly the most "epic" failure. The coal burns so hot that it can cause a burn back hopper fire. There are quite a few recorded instances of this.

I had a buddy who tried burning 25% rice coal 75% wood pellet in a quadrafire pellet stove. The stove kept shutting itself down becauee it sensed it was overheating. He bypassed the sensor and ended up melting through the firebox. Hot coals melted all the way through to the floor. Luckily this stove was in his shop on a concrete floor and not in a home.

Coal, especially anthracite is an excellent heat source. Just make sure if you chose to burn it, it is in a stove designed for it.

Deezl Smoke said:

But what if you can get enough more btu's from charcoal to offset that extra cost? What is charcoal had less residual than wood pellets? Perhaps if enough research were put into it, charcoal pellets would be less money per btu than wood pellets. These are things that deserve exploration.

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Couldn't have said it better myself. I have the resources (minues a mill to pelletize the charcoal) may as well test it out. I'd rather know for sure than always be stuck wondering. You never know unless you try (and stay within safe limits).