BWTS: How electrodialylsis technology differs

Kashif Javaid , Sales Manager, OceanSaver, provided feedback from his company’s BWMT at the 2017 GREEN4SEA Conference.  He answered a few questions about the USCG type approved OceanSaver’s BWTS and how electrodialylsis technology is different from conventional electrolysis processes. Mr. Javaid also provided a couple of key retrofit lessons in order to ensure smooth project handling.

OceanSaver’s mission is to protect the marine environment by supplying IMO, USCG and Class Certified Ballast Water Treatment Systems. Regarding the USCG Type approval, the company tested for USCG the same system which was IMO type approved. The USCG system is based on the same filtration and Electrodialysis membran cell technology as the IMO system. In terms of power consumption, it still remains the same as IMO TYPE Approved system. In the end, for the existing sailing vessels, owners are concerned about USCG upgrading; there is no risk of upgrading existing systems. Furthermore, there is no limitation in the company’s USCG certificate with regard to salinity; temperature; holding time. The operational requirements of the Electrolyte Feed Water (Approx. 1 %) also remains the same as the IMO approved system.

OceanSaver’s technology is based on filtration and Side Stream Electrodialysis with Membrane Cell. The image below depicts how the system works.

Salinity and temperature are the two factors which impact all the electrochlorination processes. Thus by having a heater as a part of standard scope and also a storage tank solution, these two factors are controlled. During de-ballasting no treatment is required. The discharge water has to be monitored according to IMO and USCG discharge standards.

The patented Membrane Cell Electrodialysis Technology is different from conventional electrolysis processes. It gives additional benefits with regards to OPEX and increased safety. The system is not a fixed dosage; it has a self -adjusted oxidant generation and dosage according to local water conditions. By using that, the company optimizes power consumption. Thus, operators are not burning equal amounts of fuel to make the oxidant. Furthermore it is a short half-life of oxidant. Moreover, corrosion in ballast tanks is a major topic and it’s going to be a major OPEX factor for the years to come. OceanSaver corrosion assessment has been done by DNV GL.

Hydrogen is a well-known by-product of all electrochlorination processes. The way OceanSaver technology is generating and separating is different because of the membrane cell.

In a conventional electrolysis method all the products and by-products, containing oxidants; chlorine gas; hydrogen are produced in one flow. In OceanSaver electrodialysis technology, hydrogen is generated and collected at source in a separate flow with no mixing of oxidant and chlorine gas.

 The system further offers some operational flexibilities and benefits. Specifically, gravity de-ballasting is possible and there is also inbuilt redundancy in rectifiers. In other words if during the operation one module fails, the system will still be in operation. Intermediate «Pause» functionality in the system ensures that you do not need to shut down the system for multiple ballasting operation at multiple ports.

Rertrofit lessons learned

Project planning and sufficient time are two of the most important lessons for a retrofit operation. If an operator believes that a retrofit project can be completed in five or even six months, this approach needs reconsideration, because unlike a newbuilding project, the retrofit is more complex as there are more parties involved in the project; the Vendor; the engineering company; the classification societies for approval; Installation Yards. Owners should take a more active role in the whole process.

Small details can matter as ship preparation before 3D scanning. For example in one case, ship crew was asked to prepare the vessel for 3D scanning (such as remove floor plates, clear the defined areas for scanning etc.) prior to attend the vessel. However, when engineers went on-board, no preparations were done. That could possibly delayed the scanning, if vessel had a short port stay.

In another case, owners re-considered and decided to change installation layout quite far in design & engineering phase. That required re-design and extended engineering time.

Then the Class would have comments and solutions which are often not acceptable for owners and subsequently they have to look for alternative solutions. Eventually, all these may lead to delays and time is money. OceanSaver recommends that starting retrofit installation operations should be start eight to ten months before the docking schedule.

Retrofit Finance

In the end, the total cost of a retrofit project including purchase BWTS, interface equipment, design & engineering, installation, commissioning is an extra cost for owners. OceanSaver can assist, through Export Credit Norway, in providing finance up to 85% of contract value. The most interesting aspect with the financing is having the free of charge fixed interest rate option which allows owners to compare the interest rate offered by Export Credit Norway to the market based interest rate and to choose the most attractive option.

Above text is an edited article of Kashif Javaid‘s presentation during 2017 GREEN4SEA Conference & Awards

You may view his presentation video by clicking here

The views presented hereabove are only those of the author and not necessarily those of  GREEN4SEA and are for information sharing and discussion  purposes only.