Sodium dry desulfurization

Its main processes are as follows:

Scope of application: Suitable for working conditions with small flue gas volume, low

SO₂ concentration and flue gas temperature range.

Process route: Flue gas containing low concentration of SO₂ → desulfurization reactor → bag filter → induced draft fan → chimney discharge.

Process：

The raw flue gas containing sulfur dioxide from the boiler or kiln enters the desulfurization reactor, where the SO₂ in the flue gas reacts with the activated sodium-based deacidifier (usually ultrafine sodium bicarbonate powder, 800-1000 mesh) to be removed. After that, the desulfurized flue gas enters the bag filter, where the solid products generated by desulfurization are efficiently captured together with the smoke in it, and the purified flue gas is sent to the original chimney by the induced draft fan for discharge.

Reaction Principle：

The desulfurizer ultrafine powder is fully mixed and contacted with the flue gas, and reacts quickly with SO₂ in the flue gas under the action of appropriate flue gas temperature. The main chemical reaction equation is as follows:

1. 2NaHCO₃(S)= Na₂CO₃(s)+H₂O(g)+CO₂(g)

• SO₂(g)+Na₂CO₃(s)=Na₂SO₃(s)+CO₂(g)

Part of the reaction:SO₂(g)+Na₂CO₃(s)+O₂ = Na₂SO₄(s)+CO₂(g)

side effects:SO₃(g)+Na₂CO₃(s)=Na₂SO₄(s)+CO₂(g) 、

2HCl(g)+Na₂CO₃(s)= 2NaCl(s)+CO₂(g)

Main equipment: including grinding equipment, desulfurization reactor and bag filter (compared with conventional bag filter, it has insulation and heating requirements). The grinding equipment must ensure that the ultrafine sodium bicarbonate powder produced is highly active and efficient, operates stably, and does not stick or clog. Its selection and configuration are directly related to the desulfurization efficiency of the system, the consumption of desulfurizer and the stable and standard operation of the system.

System composition: It consists of flue gas system, powder making and injection system, bag dust removal system, desulfurization product treatment system, nitrogen system/compressed air and electrical instrument control system, etc.

Advantage：

• The desulfurization chemical absorption reaction speed is fast, the desulfurization efficiency is high, and a smaller sodium-sulfur ratio can be used, which reduces energy consumption and operating costs, and can reduce equipment size;
• The raw material sodium bicarbonate is abundant in sources;
• The system is simple, the process is compact, the equipment is few, the system is reliable, and the maintenance and repair costs are reduced;
• Small footprint and greater flexibility;
• It is suitable for flue gas desulfurization projects with low sulfur content. When the concentration is 500-1000mg/Nm³ (some data show that the sulfur content is lower than 1000mg/Nm³), the desulfurization efficiency is guaranteed, and the economic efficiency is more prominent when the SO₂ concentration is low;
• It has strong applicability to system load changes, good load tracking characteristics, easy start and stop, can be put into use below 110% load, and has good applicability to both basic load and maximum load;
• There is no desulfurization wastewater discharge, and sewage treatment costs are exempted.