Recently, a customer reached out to us inquiring about the operation process of a gas boiler. In response to this question, our technical staff provided an explanation.

1. Heating and Drying Phase

Coal enters the furnace for heating, and the moisture in the coal begins to vaporize and evaporate. Once the natural gas boiler temperature reaches 100-105°C, the moisture has completely evaporated, and the coal is fully dried. The duration of the heating phase varies depending on the amount of moisture in the coal; the more moisture, the longer the drying phase will last.

2. Formation stage of volatile matter escaping to form coke

As temperatures continue to rise, dry coal begins to decompose, releasing combustible gases known as volatiles. After the volatiles are released from the natural gas boiler, the remaining solid material is called coke, which is almost entirely carbon, with some ash and sometimes a small amount of sulfur. This carbon and sulfur content is also referred to as fixed carbon.

3. Volatile content ignition phase

When the volatile matter from the gas boiler is released into the air and reaches a certain concentration on the same day, it begins to ignite and burn, releasing a large amount of heat and heating the coke, creating conditions for the combustion of the coke.

4. Carbon burning and ash slag formation stage

As the volatile matter approaches complete combustion, coke begins to burn, which is a chemical reaction between solid fuel and oxygen in the air. The combustion of coke is slow and takes a long time to burn out, accounting for about 90% of the total combustion time. When the outer shell of the coke is burned off, forming ash that obstructs oxygen from diffusing into the center of the coke, combustion will cease, resulting in slag.