Two-phase separation

In all these cases, both wire mesh demisters and vane packs can be used to remove liquid droplets, solid particles or separate two liquids. The selection of the demister must take into account the operating conditions, the flow velocity and the required performance.

Wire mesh demisters and vane packs are the most widely used internals for removing liquid droplets from a gas stream.

• Wire mesh demisters: layers of wire mesh form a very dense cellular structure. As the gas passes through it, liquid droplets impact the mesh filaments and are captured. Over time, the droplets are joined by other liquid particles and increase in mass until they reach and exceed the point of equilibrium with gravity, causing them to fall towards the lower part of the vessel, where they are drained. The gas stream, on the other hand, continues its path free of the liquid that, without the demister, would have been carried along with it.
• Vane packs: these separators consist of a housing containing a variable number of vanes, which may or may not be fitted with hooks. The vanes and hooks intercept and separate the liquid droplets carried by the gas stream as it passes through the pack. Once captured, the droplets flow downwards.

Velocity and performance

Under the same process conditions, wire mesh demisters operate at lower velocities than vane packs. When both high separation efficiency and high gas velocity are required, a wire mesh pad combined with a vane pack can be used, allowing the former to act as a droplet agglomerator and increase the size of the droplets entering the vane pack.
Wire mesh demisters can separate droplets down to micron-sized particles of around 3 microns, while vane packs separate droplets of around 10 microns. Considering the minimum droplet diameter, separation efficiency can still be very high, reaching up to 99.9% of the liquid particulate matter being separated.

In these cases, the internals allow the separation of two immiscible liquids. This result can be achieved using two different types of separators:

• Wire mesh coalescing packs: constructed from wire mesh in the same way as demisters for gas-liquid separation, but differing from the latter in terms of thickness, mesh type and number of mesh layers.
• Parallel plate packs: constructed from a series of parallel plates arranged along the direction of flow.

Liquid-liquid separation using our separators offers several advantages, including:

• Reduced vessel size, resulting in lower manufacturing, handling and installation costs.
• Increased purity and improved quality of the products leaving the vessel.
• Recovery of valuable products, such as glycols and amines.

Velocity and performance

Similarly to gas-liquid separation, in this case too, wire mesh demisters allow lower flow velocities than vane packs under the same process conditions. However, separation efficiency, in terms of the minimum separable droplet size, is higher.

In this case, wire mesh demisters are used to remove solid particles from a gas stream. Some common applications include:

• Desalination plants, where salt is separated from the water vapor stream. The intercepted salt droplets solidify within the mesh and are separated from the vapor.
• Filtration and purification of air used in a wide range of industrial and food processing applications.
• Filtration of solid particles from mechanical processes such as wire drawing.