Many factories come across the term “flue gas desulfurization and denitrification” when operating boilers, but they may not know what it means or what its purpose is. In simple terms, flue gas desulfurization and denitrification is the process of “treating the flue gas emitted by boilers to reduce pollutant emissions.” It is a crucial measure for ensuring boilers meet environmental standards. Below is a detailed explanation that’s easy to understand.
First, let’s clarify the core objective: When a boiler burns fuel (especially coal, heavy oil, etc.), it emits flue gas containing pollutants such as sulfur dioxide and nitrogen oxides. These pollutants can contaminate the air, damage the environment, and even result in penalties from environmental protection authorities. The core objective of flue gas desulfurization and denitrification is to remove sulfur dioxide and nitrogen oxides from the flue gas, ensuring it meets national environmental emission standards before being released into the atmosphere, thereby preventing environmental pollution.
Next, let’s distinguish between desulfurization and denitrification, as each is responsible for treating different pollutants:
Desulfurization: Primarily treats sulfur dioxide (SO₂) in flue gas. Sulfur dioxide is an acidic gas; when released into the air, it contributes to acid rain, corrodes equipment, and contaminates soil and water sources. There are two main methods of desulfurization: first, wet desulfurization, which uses an alkaline solution (such as lime water) to absorb sulfur dioxide from the flue gas, forming harmless precipitates; this method is highly efficient and suitable for most boilers; second, dry desulfurization, which uses solid desulfurization agents (such as desulfurization granules) to adsorb sulfur dioxide from the flue gas; this method requires low investment and is simple to operate, making it suitable for small boilers.
Nitrogen Oxide Removal: This process primarily treats nitrogen oxides (NOₓ) in flue gas. Nitrogen oxides are toxic gases that, when emitted into the air, form photochemical smog, posing risks to human health and the environment. The primary methods for denitrification are SCR (Selective Catalytic Reduction) and SNCR (Selective Non-Catalytic Reduction). Simply put, these involve adding a denitrification agent (such as ammonia) to the flue gas. At a certain temperature, the denitrification agent reacts with the nitrogen oxides, converting them into harmless nitrogen gas and water, thereby achieving denitrification.
It is important to note that flue gas desulfurization and denitrification equipment requires regular maintenance, such as cleaning desulfurization agents, replacing denitrification agents, and inspecting equipment operation to ensure effective desulfurization and denitrification and prevent pollutant emissions from exceeding standards. Different types of boilers require different desulfurization and denitrification methods and equipment; therefore, an appropriate desulfurization and denitrification solution must be selected based on the boiler type and environmental protection requirements.
Note: Flue gas desulfurization and denitrification are not optional steps but essential components for ensuring boilers meet environmental standards. In particular, coal-fired and oil-fired boilers must be equipped with desulfurization and denitrification equipment; failure to do so will result in penalties from environmental protection authorities. Additionally, these measures help protect the ecological environment.
