Mellaplate™ coalescer

Sulzer equipment enhances the coalescence process

The Mellaplate™ coalescer consists of a set of parallel plates or sheet metals that are either flat or corrugated. The separation process is enhanced by reducing the droplet settling distance.

Mellaplate™ Coalescer with parallel plates
Main benefits
  • Reduce droplet settling distance
  • Improved separation efficiency
  • Improved flow stability
  • Reduced risk of droplet re-entrainment
  • Efficiency maintained even with phase inversion of dispersed liquid
Main applications
  • Very suitable in systems susceptible to fouling with increased plate angle and plate spacing
Comparison table
Mellaplate W Mellaplate MG Mellaplate M Mellaplate N
Construction form Flat parallel plates Structured corrugated flat plates Structured corrugated metal sheets Structured corrugated plastic sheets
Relative capacity 1 1.5 1.5 1.5
Typical droplet
cut-off size
≥ 50 μm ≥ 100 μm ≥ 50 μm ≥ 50 μm
Pressure drop Negligible 0.5 – 4 mbar

1 – 10 mbar

1.5 – 15 mbar

Solids handling High fouling resistance Good to high fouling resistance Moderate to good fouling resistance Moderate to good fouling resistance
Remarks Also used as wave and foam breaker elements More suited for de-oiling due to the plastic surface
Mellaplate type W
 Sulzer Mellaplate W - frame and box arrangement

Sulzer Mellaplate™ W

This type of coalescer has a combination of inclined parallel plates with fixed spacing, thus reducing the droplet settling distance significantly, and enhancing the coalescence process.

This separator is developed for applications where an improvement in the performance of gravity settlers is required. The inclined plate arrangement allows the liquid phases to disengage diagonally towards the liquid interface. Normally, the flow between the plates is kept in the laminar region for better separation performance. The inclination and the spacing between the plates are fixed depending on the application, the nature of contaminants present in the mixture, and degree of separation needed.

Typically, the angle is either 45° or 60° with plate spacing from 15 to 100 mm. Due to the high fouling resistance, the Mellaplate W is, for example, used in crude oil production separators. It is also ideal for retrofitting an existing gravity settler to operate at a higher throughput and improve the separation performance.

From the construction point the Mellaplate W can be made in modular frame arrangement or boxes for easy installation through the manway.

Alternatively, it can also be constructed in one piece for vessels with access through a body flange. Our experienced engineers can assist you in designing this separator to ensure trouble-free installation and operation.
Mellaplate types M MG N
Sulzer Mellaplate M coalescer

Sulzer Mellaplate™ M, MG, and N

This type of coalescer is made of structured corrugated metal or plastic sheets.

Various universities and oil companies tested Mellaplate M, MG, and N types in oil/water separators also under moving conditions.

We supplied the first Mellaplate in 1988 for the Hutton tension leg platform in the UK. Since then, hundreds of oil/water separators have been equipped with various Mellaplate M, MG, and N types. Some of them were used as foam and wave breaker devices, e.g. in oil/water separators on Tension Leg Platforms (TLP) or floating production, storage and offloading units (FPSO).

Vessel arrangement
Horizontal 3-phase separator with Shell Schoepentoeter feed inlet device, Sulzer Mellaplate M foam breaker, Sulzer Mellaplate W coalescer, and Sulzer Mellachevron mist eliminator

Vessel arrangement with Sulzer Mellaplate coalescer

The Sulzer Mellaplate coalescer types W, M, MG, and N can be used in both horizontal and vertical vessels.

A typical sketch of a 3-phase separator that uses the Sulzer Mellaplate W as coalescer and the Mellaplate M as wave breaker device is shown below

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