Solids Sedimentation

Managing Sediment and Dune Formation

In industries that transport mixtures of liquids and solids through pipes, two common challenges are sedimentation and the formation of dunes. Sedimentation happens when solid particles settle at the bottom of the pipe, which can block the flow or damage the system. Dunes are moving piles of sediment that form under certain conditions, also causing blockages and inefficiencies. Understanding how to manage these issues is crucial for keeping pipelines running smoothly. Here’s a simplified guide, focusing on key points and solutions like using inline mixers.

Importance of Fluid Speed

The speed at which the mixture moves through the pipe is very important. It needs to be just right:

  • Too Slow: Particles will settle and may form dunes.
  • Too Fast: It can cause wear or use too much energy.

Critical Speed: This is the speed needed to keep particles from settling. It varies based on the size and type of particles and the liquid’s thickness.

How Dunes Form

In some cases, especially with pulsating (start-stop) flows, solid particles can clump together into dunes that move along the pipe. These dunes can:

  • Increase resistance, needing more power to move the mixture.
  • Wear down the pipe more quickly.
  • Block the flow if they get too big.

How the Shape of Particles Affects Sedimentation

  • Round Particles: These are easier to keep moving and less likely to form sediment.
  • Irregular Particles: They can lock together, making sediment more likely.
  • Fibrous Materials: They can create mats that trap other particles, leading to blockages.

Using Inline Mixers for Protection

Inline mixers are tools installed inside pipes that mix the liquid and solids thoroughly. They can help by:

  • Keeping particles suspended in the liquid, reducing sediment.
  • Breaking up dunes before they become a problem.
  • Protecting pumps and other equipment from damage by sediment.

Considerations for Using Inline Mixers

When thinking about using inline mixers, it’s important to choose the right type and place them correctly in the pipe. The goal is to make sure they work well with the specific mixture being transported.

Conclusion

For operators working with pipelines that carry mixtures of liquids and solids, managing sediment and dunes is a key part of keeping operations efficient and preventing damage. By understanding the factors that contribute to these challenges and implementing solutions like inline mixers, it’s possible to maintain smooth and effective pipeline operations.