Vegetable Oil SVO WVO waste cooking oil as biofuel

[John Galt]

My processor produces clear dry VO. The wet, fat, semi-solid, sludge that drops out is mixed with sawdust, and packed into empty milk cartons. One of those 'bricks' placed on a hot wood fire first thing in the morning quickly warms the house.

[Espana]

Hi there John. In reference to the milk carton bricks --- I have easy access to my chimney top and yesterday on checking the flue terminal found that the inside of the flue a greasy sooty deposit was begining to form. Past examinations have shown only soot. Main burning stock is seasoned pine and olive wood.
I have been using 'bricks' for approx 1 year, only on start up of the fire. My concern is that the deposit could lead to a chimney fire. Have you any comments on the issue?

[John Galt]

In the decades I've been heating with wood I've observed that the conditions that cause chimney deposits are cool smoldering fires and cold chimneys.
I always make sure I have a hot wood fire going before I add an oil brick. I also only add a brick when the house has cooled by at least 5°C. That way the fire runs with maximum oxygen and draft until the brick is consumed, and the incomplete combustion which causes chimney deposits is avoided.

Chimney deposits don't appear to increase with using oil bricks in my case.

I burn a mix of spruce, pine, poplar and willow. The poplar and willow burn with the least amount of chimney deposits.

[Todd T]

I made what I call "glop logs" by mixing my wvo dregs with wood chips and packing it into 16" long 'logs' made of the cardboard core from a roll of carpet. They average about 4" diameter and cut easily with a recip saw. I cut them 20", fold the ends with a hammer.

No leakage and convenient size. I'm using these in a shop heater made from a pair of 55 gallon metal drums (Northern Tools kit).

[Dave3500]

I put my WVO in my outdoor woodburning stove. Smell like I'm making BBQ chicken. I use it to get my fire going when the furnace is not needed for a few days.

I burns so complete that I barely have any creosote build up in the chimney.

Dave