The working principle of baking soda (sodium bicarbonate) used for flue gas desulfurization

Sodium bicarbonate (baking soda, NaHCO3) can be used as an adsorbent for flue gas desulfurization. It removes acidic pollutants in the flue gas through chemical adsorption. At the same time, it can also remove some inorganic and organic trace substances through physical adsorption. Spray the fine sodium bicarbonate powder directly into the high-temperature flue gas, and the sodium bicarbonate decomposes at high temperature to produce sodium carbonate Na2CO3, H2O and CO2.

NaHCO3 + HCl → NaCl + H2O + CO2
2NaHCO3 + SO2 + ½ O2 → Na2SO4 + H2O + 2CO2
NaHCO3 + HF → NaF + H2O + CO2

Generally, the flue gas temperature is between 140 and 250 °C. Due to the high activity of sodium bicarbonate adsorbents, a slight excess of sodium bicarbonate (stoichiometric factor between 1.1 and 1.3) is usually sufficient.

Due to transportation and storage, sodium bicarbonate raw materials are usually coarse particles (D50 value is about 200 microns). To achieve higher reactivity, the adsorbent must have a larger specific surface area. Therefore, the sodium bicarbonate must be ground to a certain fineness before being injected into the flue gas pipe. For example, to remove SO2, the fineness of sodium bicarbonate must reach D90 <20μm; and to remove HCl, only D90 <35μm is required. If the system is operated correctly, it can remove more than 95% of SO2; the removal rate of HCl can even reach 99%.

We can provide processes and equipmentthat meet the following performance indicators

Low failure rate and stable operation
Suitable for continuous operation, with an annual operating time of more than 8000 hours.

Automatically adjust the injection amount of desulfurizer
Real-time monitoring of the concentration fluctuations of harmful substances in the flue gas, and automatically adjust the amount of desulfurization agent injected.

Large air volume intake design
The grinding temperature can be reduced. If there is a higher temperature requirement, a cold air device can be selected.

Clean and environmentally friendly
Grinding is in closed system, little dust, low noise in a clean and environmentally friendly process.

Non-irritating, non-toxic
Additives (sodium bicarbonate) and residues are non-irritating and non-toxic.

Easy to disassemble and clean
Compact structure, easy to remove and wash mills and fans. Optional online cleaning to prevent material sticking and reduce downtime.

Intelligent control system
One-key operation, online monitoring of key parameters such as sulfur dioxide concentration, system air volume, feed volume, grinding temperature, etc.

Integrated design of grinding and classification
Achieve the desired product size by adjusting the classifier wheel speed.