Tar reduction or Removal techniques

[Kafle]

Hello, I am doing a project related to pellet water boiler. I faced a problem, tar is stains in the wall of boiler so that heat transfer rate decrease and hence decrease in boiler efficiency. The maximum temperature of boiler body is about 1600 degree Celsius. Being an Engineer, I have less knowledge in chemistry so I need help how to remove or reduce such problem?

[barfbag]

Do you add to coals or is there any ignition device?

 

I would think most of your tar comes from starting and stopping where temperatures fall below 100C, but I'm also an Engineer and not a Chemist.

 

Any Chemists out there?

 

I just found this online.. I had not thought of wet pellets slowing down the burn...

Reply on the matter from Solid Energy, supplier of Natures Flame pellets;

"Tars are usually a sign of incomplete combustion due to lack of air/heat or wet biomass fuel. As long as the fuel is dry (and if they are pellets then they will be) then it will be the boiler settings. More air and heat will burn off the tars before they form on surfaces. Get you installer to adjust the boiler accordingly."

So we have started to slowly increase the fan settings of the boiler to have it burn more hot. Hopefully this will improve combustion and reduce the tar produced.

 

[Kafle]

I used wood pellet as a fuel and automatic ignition system fitted there. Actually, tar produce due to incomplete combustion, but the boiler is highly efficient design. I find in some paper, above 1000 degree PAH (polycyclic aromatic hydrocarbon) form, which stains in wall of boiler and act as resisting device. My goal is to remove tar while operating the boiler, if there is any chemist please help me to find the chemical/catalyst which reduce/remove tar production. Thanks for reply Baryon.

[Enthalpy]

Hi,

 

I have big doubts about 1600°C at the boiler. It can be a flame temperature. A decent boiler won't attain that, among others because steel wouldn't resist it.

 

To avoid tar and soot, you could first try to obtain a complete combustion before the products reach the boiler. That is, put the boiler away from the flame (easy to try with a candle), and if needed inject air in two steps : first to regulate how much fuel burns, then to finish burning it completely.

[Acme]

Hello, I am doing a project related to pellet water boiler. I faced a problem, tar is stains in the wall of boiler so that heat transfer rate decrease and hence decrease in boiler efficiency. The maximum temperature of boiler body is about 1600 degree Celsius. Being an Engineer, I have less knowledge in chemistry so I need help how to remove or reduce such problem?

Maybe this product? You may have to break up the log as they say don't use with pellet stove. I can't find any mention of what the ingredients are, but if you/we can find the ingredients then maybe you can make your own.

 

Creasote Sweeping Log

1. The Creosote Sweeping Log burns for approximately 90 minutes. Making a wood fire prior to using CSL will heat the tar on your chimney wall, while it improves your draft.

 

2. The smoke from CSL is charged with additives, which rises and attach themselves to the creosote deposits..

 

3. Next, these creosote deposits are either reduced and/or rendered less likely to result in a chimney fire, making your next fire safer.

 

4. While burning fires over the next 1 to 2 weeks, the CSL additives which are attached to the creosote will continue to treat your chimney. Some creosote may fall back into your fireplace, smoke shelf or woodstove.

CSL COMPATIBILITY

 

WOOD BURNING APPLIANCES

Fireplaces, woodstoves, fireplace inserts, gas starter fireplaces, wood/coal stoves, wood/oil mixed boilers and wood furnaces.

...

DO NOT USE WITH

BBQs, gas logs, electrical appliances, oil stoves, pellet stoves.

Edit: This page calls into question the effectiveness of the chimney sweeping logs: >>Do Those Chimney Sweeping Logs Really Work?

Edited July 16, 2014 by Acme