The principle of a smokeless boiler is:

1. Coal is heated at low temperatures to produce coal gas,COBurning, so the smoke emission is colorless, which is called smokeless.

2. The boiler is insulated externally and the flue gas return is added internally, which not only improves the coal gasification rate but also enhances the thermal efficiency of the boiler, reducing the flue gas emission temperature to 150 ℃.

3. Smoke free boiler, also known as environmentally friendly boiler, refers to a boiler that can meet environmental requirements for exhaust emissions, not a specific type of boiler. Coal fired boilers can also meet environmental requirements for flue gas emissions after desulfurization and dust removal treatment. Coal fired boilers that meet environmental standards are also environmentally friendly boilers.