Calculation for high-viscosity pumps
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I need help calculating the head required for a pump. The fluid in question is high-concentration black liquor from a paper mill; the flow rate is 15 l/s, the temperature is 140 degrees, the viscosity is 1000 mPa*s, and the density is 1440 kg/m3. The inlet pipe of the pump has a diameter of DN150 and is 3 meters long, while the outlet pipe has a diameter of DN125 and is 430 meters long. Both pipes are made of duplex steel. The static head at the pump inlet is 2 meters, and it is 35 meters at the outlet. There are a total of 12 90-degree elbows at the pump outlet, and 1 elbow at the inlet; there are no diameter changes along the pipes, and there is a control valve at the outlet. My calculation gives around 60 meters. Could some expert help verify this? Thank you! ! !
Hello, owner. Please refer to the following 2 documents: (1) Table of common material flow velocities: https://wenku.baidu.com/view/c8ede607cc17552707220811.html. For high-viscosity liquids (1000 mPa·s), the flow velocity should be set at 0.25–0.35 m/s for a pipe diameter of DN100, and at 0.35–0.55 m/s for a pipe diameter of DN200. (2) The “Table of common flow velocity ranges for certain fluids in pipelines” in Principles of Chemical Engineering states that for water and low-viscosity liquids (at 0.1–1.0 MPa), the flow velocity is 1.5–3.0 m/s, while for high-viscosity liquids it is 0.5–1.0 m/s. Referencing the above two standards, with a flow rate of 15 L/s, an inlet pipe diameter of DN150 results in a flow velocity of 0.85 m/s, while an outlet pipe diameter of DN125 yields a flow velocity of 1.22 m/s. Please consider whether this flow velocity is too high. Here is my calculation process for your reference: 1. Calculation for the pump inlet pipeline: Flow velocity u = 0.85 m/s, pipe diameter d = 0.15 m, density ρ = 1440 kg/m3, viscosity μ = 1 Pa·s. Therefore, the Reynolds number Re = duρ/μ = 0.15*0.85*1440/1 = 183
I’m still worried about the pump inlet pipeline. Is it really necessary to install a filter and a isolation valve at the pump inlet? Only in cases where the water supply is clean does it not require a filter. If no isolation valve is installed, won’t all the material flow onto the floor when the pump is replaced? What type of pump is it, and what pressure needs to be maintained at the pump inlet in order to draw in the material without causing vacuum?
I haven’t been here for a while; thank you for your reply. There is a filter at the front end of the system, so no filter needs to be installed here; however, there is actually a manual ball valve. A static pressure of 2 meters at the pump inlet is a conservative value; the actual value is higher than 2 meters, so there is no need to worry about the inlet. In the end, Sulzer’s A22-50/O was chosen for the pump, which is also a centrifugal pump.
I haven’t been here for a while; thank you for your reply. There is a filter at the front end of the system, so no filter needs to be installed here; however, there is actually a manual ball valve. A static pressure of 2 meters at the pump inlet is a conservative value; the actual value is higher than 2 meters, so there is no need to worry about the inlet. In the end, Sulzer’s A22-50/O was chosen for the pump, which is also a centrifugal pump.
I haven’t been here for a while; thank you for your reply. There is a filter at the front end of the system, so no filter needs to be installed here; however, there is actually a manual ball valve. A static pressure of 2 meters at the pump inlet is a conservative value; the actual value is higher than 2 meters, so there is no need to worry about the inlet. In the end, Sulzer’s A22-50/O was chosen for the pump, which is also a centrifugal pump.
Thank you for such a detailed calculation. As you mentioned, the outlet pipe size was ultimately chosen to be 150, with a flow rate of 0.85 m/s. The statement that the static head at the outlet is 35 meters is inaccurate; it should be that the pump’s lifting height is 35 meters, with no pressure at the outlet equipment. A ball valve was ultimately selected as the outlet control valve. With these values, the total head comes out to 68 meters, so there is no need for a booster pump.
Leaving a message is a virtue; thank you for responding to me in such detail as well. I haven’t been to Shanghai Chuan for a long time either. While responding to your post, I was actually doing calculations in this area – our company has a new project, and I’m responsible for the process flow; I’m checking whether the selected pumps and other equipment meet the required specifications. I didn’t study \"Principles of Chemical Engineering\" seriously in college, and after starting work I realized that I hadn’t mastered this practical reference book, which made it difficult for me to deal with specific problems. I was exactly studying \"Principles of Chemical Engineering\" during that time, so I took the opportunity to use those lessons to work on your practical problems as practice exercises:D
The owner ultimately chose a Sulzer pump. I don’t know much about Sulzer; I only know that they are leaders in the world when it comes to packing materials. Our company uses their packing in the distillation towers.