Purification Technology for Flue Gas of Boilers and Kilns — Brief Analysis of Desulfurization and Denitrification Technologies

In industries such as coal and gas-fired boilers, ceramics, and glass manufacturing, kilns generate substantial amounts of nitrogen oxides (NOx) and sulfur oxides (SOx) during operation. These are major precursors to acid rain and smog. Therefore, desulfurization and denitrification are indispensable steps in flue gas purification.

1. Denitrification Technology: How to Remove Nitrogen Oxides (NOx)?
   Denitrification is mainly divided into two technical pathways:

• SNCR (Selective Non-Catalytic Reduction)

• Principle: Without the use of a catalyst, an amino-containing reductant (such as ammonia water or urea solution) is injected directly into the high-temperature zone of the furnace (850-1100℃). It undergoes a reduction reaction with NOx to form harmless N₂ and H₂O.

• Features: The system is simple and has low investment costs, but offers moderate denitrification efficiency (30%-50%).

• SCR (Selective Catalytic Reduction)

• Principle: With the aid of a catalyst, a reductant (typically ammonia gas or urea) is injected into the flue gas. It undergoes a selective reduction reaction with NOx at lower temperatures (280-400℃) to produce N₂ and H₂O.

• Features: Extremely high denitrification efficiency (can reach over 90%), making it the mainstream technology for meeting ultra-low emission standards. However, both investment and operating costs are relatively higher.

2. Desulfurization Technology: How to Remove Sulfur Oxides (SOx)?

• Core Equipment: Desulfurization facilities (mostly wet desulfurization towers, which are essentially specialized spray towers).
• Principle: Alkaline absorbents (such as limestone slurry or NaOH solution) are brought into full contact with the flue gas inside a spray tower. Chemical reactions occur, effectively absorbing and removing SO₂ from the flue gas.
• Features: This is a mature technology with high desulfurization efficiency (>95%). The by-products can be recycled, making it the most widely applied desulfurization technique.

Zhonghuan Oasis Advantages:

We can provide you with the most suitable SCR denitrification units, SNCR denitrification units, or combined SNCR/SCR technologies based on your furnace type, fuel, on-site space, and emission requirements. We also supply highly efficient desulfurization facilities, offering a full-process service from design and manufacturing to installation and commissioning, ensuring long-term stable compliance of flue gas emissions.