The flue gas desulfurization (FGD) circulation pump is one of the key components in the FGD system. Its primary function is to circulate the absorption liquid within the desulfurization tower, ensuring the continuous progress of the desulfurization reaction. This article will discuss the function, working principle, and the importance of the FGD circulation pump in the desulfurization system.

I. Function of the FGD Circulation Pump: The FGD circulation pump serves several crucial functions, including:

1.Liquid Circulation: The pump is responsible for extracting the absorption liquid, which has absorbed sulfur dioxide (SO2), from the bottom of the desulfurization tower and returning it to the top of the tower. This circulation ensures the reuse of the absorption liquid, which captures SO2 from the flue gas.

2.Sustaining Desulfurization Reaction: By circulating the absorption liquid back into the desulfurization tower, the FGD circulation pump maintains the equilibrium of the reactive liquid inside the tower, ensuring the stability and durability of the desulfurization process. The desulfurization tower plays a critical role in converting SO2 into sulfuric acid through chemical reactions, and the circulation pump's function is to sustain this reaction by maintaining the balance of the reaction liquid.

3.Temperature Regulation: The FGD circulation pump also enables temperature regulation within the desulfurization tower by controlling the circulation speed of the absorption liquid. By adjusting the pump's flow rate, the residence time of the absorption liquid inside the tower can be modified, affecting the reaction rate and efficiency of the desulfurization process.

II. Working Principle of the FGD Circulation Pump: 

The FGD circulation pump employs a centrifugal pump design, and its working principle can be divided into the following steps:

1.Liquid Extraction: The FGD circulation pump is connected to the liquid pool or tank at the bottom of the desulfurization tower via an inlet pipe. The pump's impeller creates a negative pressure as it rotates, extracting the SO2-absorbed liquid into the pump.

2.Liquid Pumping: The extracted absorption liquid is forced to flow towards the pump's outlet through the rotation of the impeller, which imparts centrifugal force to the liquid. The design of the centrifugal pump allows the liquid to gain sufficient kinetic energy under the high-speed rotation of the impeller.

3.Recirculation: The liquid at the pump's outlet is transported back to the top of the desulfurization tower through the outlet pipe, where it re-enters the tower for recirculation. This enables the absorption liquid within the desulfurization tower to continuously capture SO2 from the flue gas, ensuring an efficient desulfurization process.

4.The FGD circulation pump is typically equipped with flow control devices and pressure monitoring systems, allowing real-time adjustments and monitoring of the pump's flow rate and pressure. This ensures the safe operation of the system and maintains the stability of the desulfurization efficiency.

The FGD circulation pump plays a crucial role in the FGD system. By circulating the absorption liquid, it sustains the desulfurization reaction, regulates the temperature within the desulfurization tower, and enhances the desulfurization efficiency. Understanding the function and working principle of the FGD circulation pump is essential for the design and operation of the desulfurization system, as it contributes significantly to environmental protection and the sustainable development of industrial production.