Long-flame coal grade DG (ДГ, long-flame gas coal) is the most common bituminous coal for heating in Ukraine. It contains 35-45% volatile matter, so it lights from paper and kindling like firewood, burns with a long bright flame and quickly heats up the boiler's heat exchanger. Its calorific value is about 5,500-6,500 kcal/kg, roughly 6.5-7 kWh per kilogram: less than anthracite, but almost twice as much as dry firewood.
Which boiler is it for. DG burns on natural draught, so it suits any solid fuel boiler, including a simple one without a fan, as well as stoves, potbelly stoves, long-burning boilers and sauna stoves. It is the fuel for those who need to heat a house quickly and load the boiler several times a day. For automatic boilers with an auger, small AS anthracite is a better choice.
Things to know. Compared with anthracite, long-flame coal burns out faster and gives more smoke and soot, so the chimney needs cleaning more often: once every one or two months during the season. It is best added in small portions onto a glowing bed rather than filling the firebox completely. Ash content is 10-20% depending on the batch.
Fraction. 50-100 mm is large graded coal for manual loading: big lumps burn longer and do not fall through the grate. Run-of-mine DG coal 13-100 mm (mixed fractions) is cheaper per tonne and supplied on request for boiler houses.
Packaging. 25 kg bag: for a house, 40 bags per tonne, easy to store under a canopy. Big bag of about 1000 kg: for a warehouse with a forklift. Bulk: by truck, unloaded onto a yard or into a boiler house bunker, at the lowest price per tonne.
Price and delivery. Prices per bag and per tonne are in the table below; the price per tonne goes down with volume. Delivery across Ukraine from our warehouse with our own vehicles, and to other regions by carrier. Boiler houses, companies and dealers get a supply contract, bank transfer payment with VAT and a test report for each batch.
How to burn long-flame coal
Lighting. Put paper and dry kindling on the grate and a 5-7 cm layer of coal on top. Once it catches, add more up to 10-15 cm. Long-flame coal does not need a "cushion" of firewood the way anthracite does.
Air. Keep the ash pit door slightly open while there is a flame: the volatile matter needs oxygen, otherwise it goes up the chimney as soot. You can reduce the draught once the bed has turned into an even glow.
Adding fuel. In small portions onto a glowing bed, without filling the firebox completely; otherwise the flame goes out and the boiler smokes. One 25 kg bag in a domestic boiler usually makes two or three loads.
Ash. Clear it out before each lighting: a layer of ash on the grate blocks the air from below. The ash content of DG is 10-20%, so a bag leaves 2.5-5 kg.
Safety. Do not close the damper while there are blue flames on the bed: that is carbon monoxide burning off. A CO detector for the boiler room costs less than one bag of coal.
Storage. Under a canopy, on a pallet, away from open fire. Wet coal burns worse and gives more smoke; dry coal keeps for several seasons without losing calorific value.
