Flue Gas Desulphurization Plants

Sodium bicarbonate is a chemical compound with a chemical formula NaHCO₃, which is widely produced in our country. It is one of the sodium salts and has anti-acid properties.

 

Sufficiently micronized sodium bicarbonate provides effective reduction of acid pollutants in the flue gas after combustion. Although the use of sodium bicarbonate in this field is not well known in our country, its use is very common, especially in Europe and America. The use of sodium bicarbonate in flue gas cleaning takes place in the form of dry sorbent injection. A reaction time of 2 seconds is needed for sodium bicarbonate on a dry basis to capture the acids in the waste gas.

 

Sodium bicarbonate (NaHCO₃) turns into sodium carbonate (Na₂CO₃) at temperatures above 140-200 °C, and water (H₂O) and carbon dioxide (CO₂) are formed as a result of chemical reaction.

 2NaHCO₃ → t > 140 ° C → Na₂CO₃ + CO₂ + H₂O         


The resulting product is highly reactive and ready to reduce acids in gas. After that, the following reactions occur in the waste gas.

 Hydrochloric Acid (HCl)

2HCl + Na₂CO₃ ⇒ 2NaCl + CO₂ + H₂O                            Sodium Chloride – NaCl


 Sulphuric Acid (SO_x)

SO₂ + Na₂CO₃ + ½ O₂ ⇒ Na₂SO₄ + CO₂                                    Sodium Sulphate - Na₂SO₄


The waste gas treatment reagents used for combustion processes are listed in the table below.



Typical reduction rates of dry sorbents are given in the table below.

As is apparent from the above table also made using sodium bicarbonate waste gas removal process in Turkey achieved emission values can reach values much lower than lime which is widely used. Thanks to its high reactivity, the same amount of HCL and SO_x gases can be removed with an average of 4 times less sodium bicarbonate than lime.

In addition, while the capture rates of waste gases vary at different temperatures in the use of lime, the rates above 200 °C in sodium bicarbonate are at a constant level.

The graph below shows the changes in SO₂ removal at different furnace temperatures.




The graphs below show the efficiency of sodium bicarbonate and trona in the removal of SO_x gases of different sizes.



In order to meet the desired emission values, it will be sufficient to establish a reactor system that will provide 2 seconds reaction time by grinding technical type sodium bicarbonate to d₉₇: 20 microns.



In addition to the efficiency of using sodium bicarbonate in gas reduction, another benefit is that the waste product is a usable salt. In addition, unlike lime, sodium bicarbonate is lightened after the reaction, so the amount of solid waste generated and therefore the waste disposal cost for companies is lower.




Our company supplies, manufactures and installs package systems that grind sodium bicarbonate and inject it into the system in order to control flue gas emissions. One single system can serve up to 4 different burning lines at the same time. The system automatically grinds standard sized sodium bicarbonate and injects the required amount into the system. Different sized systems are available for different capacities.