1、 Fuel control (most easily overlooked, directly affecting smoke and dust)
a. Dry hardwood must be used
The moisture content should be controlled within 15% to 20%. Wet wood can produce a large amount of tar, black smoke, and condensate, which can clog the flue; Prioritize oak, birch, and beech wood; Avoid cork with high resin content such as pine and fir, and do not burn bark, wet branches, garbage, plastic, painted wooden boards.
b. Storage: The firewood shed should be ventilated and rainproof, and should be air dried for at least 12 months.
2、 Selection of fireplace body (source emission reduction)
a. Priority should be given to selecting secondary combustion (secondary air intake) fireplaces that are EPA certified or comply with domestic biomass stove emission standards
Secondary air intake structure: High temperature air is injected into the upper part of the furnace to reignite the combustible flue gas (carbon monoxide, tar mist) generated during the initial combustion, significantly reducing smoke and dust. The high-end model comes with three air intakes.
b. It is not recommended to use old-fashioned ordinary cast iron single inlet fireplace, as it has low combustion efficiency and large smoke exhaust.
c. Power matching: The room area corresponds to a suitable furnace body, and do not choose a fireplace that is too large; The stove is too big, the low fire burns slowly, the furnace temperature is low, and it is easy to smoke and accumulate tar.
3、 Design of flue (chimney) system to solve the problem of smoke backflow and exhaust obstruction
a. Chimney height: More than 0.5m above the roof, the total height is recommended to be ≥ 4.5m; ensure sufficient suction force (negative pressure).
b. Pipeline: Try to be straight, short, and have fewer bends, with no more than 2 bends; The inner diameter of the flue should match the outlet of the fireplace, without reducing the diameter. The inner wall of the flue is smooth, and a double-layer insulated stainless steel chimney is recommended.
-Insulated chimney: maintains the temperature of flue gas, prevents cooling and condensation of flue gas, reduces tar adhesion, and avoids flue blockage.
c. Smoke prevention:
-Stay away from eaves, ventilation openings, and high-rise building airflow areas;
-Install windproof and rainproof chimney caps to prevent strong winds from pouring in;
-Indoor air supply: A sealed new house must reserve an outdoor air inlet. The house has good air tightness, and combustion consumes oxygen. Indoor negative pressure can cause the fireplace to smoke.
4、 Correct operation method (improve combustion, reduce emissions)
a. Ignition stage: Start the fire first, use small firewood to start the fire, and then add coarse wood after the furnace is heated up; Directly adding large pieces of wet wood to the cold furnace instantly produces a large amount of black smoke.
b. Combustion strategy: Maintain high temperature combustion and avoid prolonged low-temperature combustion. Close the air door and let it burn, causing low furnace temperature and a sudden increase in tar and particulate matter. When low temperature is required, do not turn off the air intake completely and add a small amount of wood intermittently.
c. Adding firewood: Do not fill the furnace with small amounts multiple times at once, as it may hinder air circulation.
5、 Regular maintenance to prevent potential hazards and continuously control emissions
a. Flue cleaning: Clean once a year before the heating season; Burn too much and the firewood is damp, clean it every six months. Tar accumulation not only increases smoke exhaust, but also triggers flue fires.
b. Check the sealing: The aging and leakage of the glass sealing strip on the furnace door can damage the air ratio inside the furnace and deteriorate combustion; Regularly replace the asbestos rope sealing strip.
c. Clean the ash box: Do not stack the ash too high to block the bottom air intake. Keeping a small amount of bottom ash can help with insulation, but it should not be too thick.
