How is sulfur dioxide produced in boiler?

Sulfur dioxide is a common sulfur oxide, which dissolves in water to form sulfurous acid. When oxidized in the presence of PM2.5, it will quickly and efficiently generate sulfuric acid and cause acid rain. Therefore, the concentration of sulfur dioxide in boiler flue gas directly affects the environment, and is valued by many parties.

How is sulfur dioxide produced in boiler?

The principle of how sulfur dioxide is produced in boilers using different fuels is different. Sulfur in solid fuels in the form of organic sulfur and pyrite sulfur all take part in the reaction during the combustion process, oxidizing to sulfur dioxide, while sulfate does not take part in the combustion. The sulfur in the liquid mainly exists in the form of free sulfur, hydrogen sulfide, etc., which can easily react with oxygen and be converted into sulfur dioxide during fuel combustion. The sulfur in the fuel mainly exists in the form of gaseous hydrogen sulfide, and almost all of it is converted into sulfur dioxide during combustion, so the amount of sulfur dioxide produced is directly proportional to the sulfur content in the fuel and the oxygen content in the boiler.

Control method of sulfur dioxide concentration in boiler

After understanding how the sulfur dioxide in the boiler is produced, it is possible to control the emission of sulfur dioxide in a targeted way. The specific methods mainly include the following three categories:

1. Desulfurization before combustion

Adopt desulfurized coal or clean fuel natural gas.

2. Desulfurization in combustion

In-furnace calcium injection desulfurization is common in circulating fluidized bed boilers. The characteristics of low-temperature combustion of circulating fluidized bed boiler make it possible to adjust the distribution of boiler heating surface, and ensure that the furnace combustion temperature is between 860 and 880, which is consistent with the combustion desulfurization temperature of most natural limestone.

3. Desulfurization after combustion

Flue gas desulfurization technology should be more common environmental protection methods, including limestone-gypsum method, magnesium oxide method, ammonia method, sodium alkali method, double alkali method, etc. With the strict requirements of environmental protection, boiler tail gas treatment systems are mostly integrated technologies of desulfurization, denitrification and dust removal.

ZOZEN Boiler mainly produces energy-saving and environment-friendly industrial boilers, covering oil-fired boilers, gas-fired boilers, coal-fired boilers, biomass-fired boilers and thermal oil heaters.