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Coalescer Pack / Nutshell Filters

Nutshell Filters

For most applications, first and second stage separation units are sufficient to meet the regulatory discharge requirements. However, when the discharge requirements are more stringent and require lower concentration of oil in water, nutshell filters are utilized. Nutshell filters use a mixture of nutshells as the filter media. Nutshells allow for the oil to collect on the surface of the nutshells while also being able to capture solids.

Process Description

The nutshell filters have a simple process. Oily water enters the vessel where it passes through the nutshells under pressure. The oil and solids get trapped within the filters and the clean water exits the bottom of the vessel. To remove the oil and solids from the filter media, a backwash process is used. The backwash process consists of fluidizing the bed, removing the contaminated water, allowing the filter to settle and finally rinsing the filters to remove any contaminates that may still be present. The process uses at least two filters: one filter online and the second filter is being regenerated and on standby. Depending on your process requirements, SPEC can deter­mine the appropriate number of filters required to provide the most optimized design. SPEC designs and manufactures nutshell filters that provide the following advantages:

  • Efficient design
  • Skid mounted packages
  • Pecan and walnut shell blend
  • High solids removal efficiency
  • Process water used for backwash eliminating need for clean water source
  • ASME coded vessels
  • Can deliver as low as 5 ppm oil in water concentration