WHY FILTER SEAWATER?
Seawater filtration is a diverse field spanning various industries, and some of the most popular applications are as follows:
- Oil and gas industry: Seawater injection for enhanced oil recovery in offshore fields
- Water Treatment: Desalination in the production of portable water
- Aquaculture/Hatcheries: Raw water treatment for culture ponds
WHAT ARE YOUR OPTIONS WHEN CHOOSING A SEAWATER FILTER SYSTEM?
It is important to choose a suitable material for the filter housing, one which can withstand the corrosive salts in seawater. While Aluminium and Stainless Steel grade 304 are commonly used in the construction of boats and other marine structures, they have limited corrosion resistance and require significant maintenance or frequent washing with fresh water.
Stainless Steel grade 316 – commonly termed “marine grade” stainless is the material of choice. In this grade, 2% molybdenum is added to further improve the corrosion resistance. This is especially important in a filter housing where the fluid velocity is low, allowing for potential accumulation of salts in these “dead-zones”, further accelerating corrosion.
For more critical applications or when filtering seawater in hotter climates, housing manufacturers used to fabricate rubber-lined vessels for improved corrosion resistance. Recently however, they have been overlooked in favour of duplex stainless steel type compositions as the latter has the advantage of being cheaper and stronger than its rubber-lined counterparts.
Another viable option is using FRP/PP which has great corrosion resistance in seawater and can be made as strong as steel. It has found widespread use as Reverse Osmosis Module Housings. For micro filtration applications however, each housing module typically only hold a single disposable filter element, and multiple modules have to be combined to cater for higher flow rates.
REUSABLE OR DISPOSABLE FILTER ELEMENT?
If solids loading is high or the system is in a remote location, a self cleaning filtration system can be considered. While this would involve less opex compared to a disposable filter system, it will have a higher upfront cost as the system will include a backwash pump, storage tank and additional components such as control system, valves etc. Nonetheless, disposable filter elements can filter out very tiny particles including bacteria (down to 0.2 micron) and would be necessary if very fine filtration is desired.
HOW CAN WE HELP ?
FILTRAFINE MFB Series multi-round bag filter housings allows for quick change out, while its NHV High Flow Series is great for more critical filtration applications. These housings comes with Stainless Steel 316, 316L or Duplex 2205 grades to give you the ideal corrosion resistance for your application. Economical PP and FRP housings are also available to fit your budget and prevent cost overruns. You may learn more about these products below:
FILTRAFINE NHV HIGH FLOW FILTER HOUSING
FILTRAFINE MFB SERIES BAG HOUSING
We’d love to hear your opinions, comments and thoughts so please feel free to comment below. If you would like us to work on your filtration issues, please drop us an email and we’d be happy to!