NEI BWTS to be fitted to crude carrier

Jan 24 2014

An NEI Treatment Systems ballast water treatment system (BWTS) that can also be used as an inert gas system for cargo tanks is being fitted on board a tanker in China and will undergo sea trials in March.

Unlike most BWTS systems, which rely on filtration, chemicals, or UV treatment of the ballast water, the NEI system is based around a patented oxygen stripping generator called the Venturi Oxygen Stripping (VOS) system.

This system works by stripping oxygen to a level of 0.1% – 0.2% oxygen content, killing any invasive species present.

The VOS system removes ~95% of the dissolved oxygen from the ballast water.  During de-ballast, the water is returned to normal oxygen levels by the physical process called Henry’s Law, and by the oxygenated water the ballast is entering.

“We are now currently installing the system getting ready to go to sea trials,” Jeffrey Barber, NEI executive vice president – global sales and marketing, told a customer event in Singapore recently. “That is a single stripping gas generator that we use for both cargo topping and cargo inerting and ballast water treatment simultaneously. So two traditionally separate functions are now consolidated into one.”

He said that this provided a single reference point for maintenance and management, as well as simplifying functions, such as crew training. “There’s no reason we can’t manage and direct cargo topping and cargo inerting at the same time,” Barber said.

NEI installed its first shipboard system in 2005 and through the stripping of oxygen from the ballast water claimed significant gains in terms of preventing corrosion. Independent studies by the US Naval Research Laboratory and BMT Fleet Technology showed that ballast water tank steel corrosion was reduced by 84%. “That has a huge impact for a vessel over its life on coatings and structure. We are not just overhead, we’re not just an expense,” Barber stressed.

The Chinese vessel is a coastal crude oil tanker. The NEI system has been delivered and is already installed. 

“This system is a good fit for vessels operating at ~3,000 cu m per hour total ballast rate, as NEI can produce ~7,000 cu m per hour of inert gas, as the system must be able to ‘keep up’ with both the ballast pumps for treatment and the cargo pumps for inerting,” Barber explained.  

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