What Factors Affect the Flow Head of the Vertical Slurry Pump

Impeller diameter: The larger the impeller diameter, the greater the range and force of the blades on the slurry at the same speed, the greater the head and flow rate, and vice versa.

Impeller speed: According to the basic principles of the pump, the impeller speed is proportional to the head and is also positively correlated with the flow rate. When the speed increases, the energy obtained by the slurry increases, and the head and flow rate will increase; when the speed decreases, the head and flow rate will decrease.

Impeller wear: The impeller will be worn during the long-term conveying of slurry. After the impeller wears, the blade shape changes and the surface roughness increases, resulting in a decrease in the pushing capacity of the slurry and a decrease in the head and flow rate.

Media density: The greater the density of the slurry, the greater the resistance the pump needs to overcome at the same impeller speed and diameter, the more energy it consumes, and the lower the head, but the flow rate generally does not change much. If the density exceeds the design range of the slurry pump, it may have a significant impact on the performance of the pump.

Media viscosity: When slurry with a higher viscosity flows in the pump, the internal friction force is high and the flow resistance increases, which will reduce the head and flow rate of the slurry pump.

Particle size and concentration: The larger the solid particle size and higher the concentration in the slurry, the more severe the wear of the impeller and runner of the slurry pump, and the greater the flow resistance, which will lead to a decrease in the head and flow rate.

Pipe length and diameter: The longer the pipeline, the greater the resistance loss, which will increase the head loss of the slurry pump and reduce the flow rate accordingly. The smaller the diameter of the pipeline, the higher the flow rate, and the greater the resistance loss, which will also reduce the head and flow.

Pipe accessories: Elbows, valves and other accessories in the pipeline will increase flow resistance. The more elbows and the larger the angle, the smaller the valve opening, the greater the resistance, and the more obvious the impact on the head and flow.

Other factors

Installation height: If the installation height of the vertical slurry pump is too high, it may cause the inlet pressure of the pump to be too low, which is prone to cavitation, which will reduce the head and flow of the slurry pump.

Sealing situation: If the sealing device of the slurry pump leaks, it will cause the slurry in the pump to flow back, reducing the effective flow of the slurry pump, and may also affect the head.

14. Reasons for the slurry return of the desulfurization pump

The main reasons for the slurry return of the desulfurization pump are as follows:

Valve problem: If the entrance door is not closed tightly, the slurry will slowly flow backwards from the absorption tower and other parts into the desulfurization pump.

Pipe layout and connection problems: If the slurry circulation pump nozzle is a bidirectional nozzle, the slurry from the upper spray layer may enter the lower slurry circulation pump pipeline through the nozzle and finally deposit in the pump body.

Pump body failure: The desulfurization pump impeller is worn, damaged or the gap is too large, resulting in insufficient head and flow of the pump, and the slurry cannot be transported smoothly, causing the slurry to return to the inlet or other parts of the pump. If the pump's mechanical seal is damaged, the slurry will leak from the seal and may cause slurry return. Inadequate pressure of the machine sealing sealing water or impurities will cause wear on the mechanical sealing ring and cause the slurry to enter the machine sealing place.

Excessive foam of slurry: The content of organic matter in the slurry in the absorption tower increases. If the boiler is not burned sufficiently or oil is poured during operation, the unburned substance in the fly ash enters the absorption tower with the flue gas, and a saponification reaction occurs to form an oil film. It is "pressed" by the oxidized air and is prone to overflow and return of slurry. The increase in the heavy metal content in the slurry will increase the surface tension of the slurry and produce foam, which will lead to abnormal liquid level of the absorption tower and return to the slurry.

Gas-liquid balance problem: During the operation of the desulfurization system, shutting down the oxidation fan or starting the slurry circulation pump may destroy the gas-liquid balance of the slurry in the absorption tower, and a large amount of foam is generated to cause the pressure and liquid level in the absorption tower to change, causing the slurry to return.

Improper liquid level control: The liquid level of the absorption tower is too high, exceeding the designed working liquid level range of the desulfurization pump, and the slurry is prone to return from the outlet or other parts of the pump under the action of gravity. The level meter fault display is inaccurate, which causes the operator to misjudgment the actual liquid level and fail to adjust the liquid level in time, which will also occur similar situations.

Poor quality of slurry: The desulfurization absorber limestone contains excessive foaming agents such as MgO, which reacts with sulfate ions to produce a large amount of foam, which may cause slurry back.

Water quality problem: The water quality of desulfurization process water is poor, such as containing a large number of heavy metal ions, COD, and BOD exceeding the standard, may promote the generation of foam and lead to slurry return.

The overflow tube is unreasonable: siphon occurs, and as long as the liquid level in the absorption tower is higher than the end point of the overflow liquid, it will continuously overflow, which may cause the slurry to return from the overflow tube.

Installation problem: When installing a desulfurization pump, if the slope of the inlet and outlet pipeline does not meet the requirements, or the pipeline is blocked or excessively bent, it will affect the normal flow of the slurry, causing the slurry to accumulate in the pipeline and increase the pressure, causing the slurry to return to the pump body.