Guide to Shop Warman Centrifugal Slurry Pump in CNSME PUMP

Ⅰ. Principle

SO2 is one of the main air pollutants and an important control indicator of industrial waste gas pollution in China. At present, all coal-fired machine units in China have implemented flue gas desulfurization projects, among which the dominant desulfurization technology is limestone/gypsum wet flue gas desulfurization (WFGD). In this process, limestone slurry is used as an absorbent, which is in countercurrent contact with the flue gas in the desulfurization tower and then is fully mixed. After the SO2 in the flue gas reacts with the absorbent, it chemically reacts with the oxidizing air that is blown by the oxidizing fan to form gypsum.

There is a slurry tank at the bottom of the absorption tower, and the fresh absorbent is pumped into the slurry tank through a limestone feeding slurry pump; under the function of the agitator, it is mixed with the existing slurry in the slurry tank; then, the slurry circulating pump will raise the mixed slurry to the spray layer and spray it down to contact with the flue gas in counter-current flow. Efficient and timely replenishment of fresh absorbent is critical throughout the whole process. If the supplementary amount is insufficient, it is difficult to guarantee the desulfurization efficiency; if the supplementary amount is too high, it will reduce the utilization rate of the absorbent, and affect the quality of the desulfurization by-products. Therefore, limestone slurry pump control is an important part of FGD operation.

Ⅱ. Pumps required by the processing system

1. Limestone preparation system

2. Pump for an absorption tower system

3. Flue gas system

4. Pump for gypsum dewatering system

5. Pumps for discharge systems

6. Pumps for wastewater treatment systems

Except for the flue gas system, the above systems will all require slurry pumps. In the absorption tower system, the injection volume is relatively large, so the diameter of the pump is relatively big. The pumps in this part are large-scale special pumps designed for desulfurization, and the pumps used in other systems are our commonly used small and medium-sized slurry pumps. According to the situation of the slurry, the material selected of the flow parts is both wear-resistant and corrosion-resistant.

Sketch of FGD System

Circulating pump for FGD system being used at Site

When the rolling bearing is working, the inner seat ring is matched with the journal, and the outer seat is matched with the bearing seat, and the inner seat can be rotated during the work, but the rotation of the outer seat ring has a more serious impact on the bearing life, so the inner seat ring should be rotated as much as possible during the design.

In the rolling bearing with the inner seat rotating, the inner seat and the journal, the outer seat and the bearing seat must be over-matched, but the inner seat should be tighter than the outer seat, so that when the shaft is stretched due to the temperature increase in the work, it can have an adjustment effect. The bearing seat has enough steel to prevent the working life of the bearing from being affected by the deformation of the support.

When there are rolling bearings at both ends of the shaft, one end of the bearing can be fixed on the bearing seat, and the other end must have an axial clearance, which can produce axial movement in order to eliminate the influence of the change in the length of the shaft on the bearing.

After the desulfurization pump bearing seat ring is matched, the bearing cover is added outside, and the embedded flange is just against the bearing outer seat ring, and then the bearing cover is fixed on the bearing seat with screws. If the bearing is required to have the possibility of axial movement, there can be a gap between the bearing outer seat ring and the bearing cover, or a soft gasket can be added between the bearing cover and the bearing seat to adjust.

Follow these three key instructions to determine the flow rate:

1. If the production process specifies minimum, normal, and maximum flow rates, use the maximum flow rate as the benchmark.
2. If only the normal flow rate is given, allocate a margin:

• For high-flow, low-head pumps (ns > 100), allow a 5% margin.
• For low-flow, high-head pumps (ns < 50), allow 10%.
• For pumps with 50 ≤ ns ≤ 100, use a 5% margin. Increase to 10% for poor-quality pumps or harsh conditions.

1. Convert weight-based flow rates to volumetric flow rates if necessary.

Accurate flow rate determination improves operational efficiency.