Pacific Green Technologies (PGT) of Dover, Delaware, has spent more than a decade designing, planning, manufacturing and implementing scrubbers on vessels.
Its “ENVI-Marine” exhaust gas scrubbing device can be supplied as an open loop, open loop hybrid-ready or hybrid system capable of both open and closed mode operation.
Open loop scrubbers are best suited for tankers, reflecting the fact that the vessels are mostly operating on deep sea routes and ports outside ECAs (emissions controls areas).
In an open loop scrubber, the exhaust gas in the scrubber is treated with seawater, producing sulphuric acid.
The system relies on seawater alkalinity. The alkalinity of seawater neutralizes the acid and the treated washwater can be discharged into the sea. There is no need for alkalizing chemicals and no requirements for shoreside disposal or for the treatment of washwater.
ENVI-Marine is smaller, more efficient and cheaper to install than many competitor’s products.
Its “TurboHead” technology creates an interactive contact between the seawater and the exhaust gas in a turbulent zone containing a high amount of surface area for gas/ liquid absorption.
This high energy liquid/gas interaction ensures both the residence time and complete interaction required to achieve the high efficiency removal of sulphur from the exhaust gas and the extreme turbulent interaction transfers the particulate matter from the gas to the scrubber fluid.
Naked scrubber
Building on its success and responding to shipowners calls for lower CAPEX and OPEX levels, PGT has taken the ENVI-Marine system one step further developing a new ‘naked scrubber’.
The ‘naked scrubber’ is an enclosureless stainless steel scrubber which offers further cost savings, a faster retrofit turnaround time - cutting the dry dock installation costs by at least 20%, offering a low-risk installation process and a 15% reduction in weight and lower energy requirements.
Using the same technology as the ENVI-marine, the new naked scrubber is more efficient, using less power and offering considerable cost savings.
PGT’s scrubber orders
To date PGT has installed scrubber technology on more than 60 vessels and has more than 90 orders in the pipeline.
In the twelve months leading up to the IMO 2020 implementation date, PGT saw demand steadily increase, with enquiries coming in from all types of vessels - bulkers, tankers and container.
Since the beginning of the year, PGT’s enquiries have been for larger vessels, with more bulkers – panama, capsize, handymax sizes, and more installations on order for VLCs, suezmaxes, aframaxes and MRs.
Looking ahead, China is starting to manufacture again and thanks to its joint venture with the massive state-owned engineering company PowerChina, PGT will be able to return to its full manufacturing capacity, producing one scrubber every 48 hours.
Strong environmental credentials are likely to become increasingly important for tanker operators, which can only be a good thing for scrubbers. They offer environmental compliance exceeding all other solutions alongside operational certainty.
Scrubber background
At the beginning of this year, most of the world’s shipping fleet switched from using high sulphur fuel (HSFO) to using low sulphur fuel oil (LSFO), to comply with the International Maritime Organization’s (IMO) global sulphur cap.
Faced with various options for compliance a large number of shipowners – 14 per cent of the world’s fleet - opted to continue using HSFO and to fit an exhaust gas cleaning system or ‘scrubber’ to their vessels, in order to comply with the sulphur cap.
Scrubbers offer the most effective way of reducing the pollutants that contribute most to a wide range of serious health problems.
They remove the sulphur oxides from the exhaust gases of ships’ engines and boilers as well as up to 94 per cent of particulate matter, up to 60% of black carbon, and a significant amount of the polycyclic aromatic hydrocarbons.
As a result, and following considerable scientific analysis and scrutiny, they have been endorsed as an approved method of compliance by the IMO, European Union and US Environmental Protection Agency.
Many shipowners using LSFO have faced significant supply and quality issues.
Some of the new LSFO fuels have caused engine and equipment damage as engineers adapt to operational challenges resulting from different chemical constituents, leading to unscheduled vessel downtime.
Refineries are still producing HSFO and the supply chain is well established, in comparison vessels relying on LSFO have not always found supplies to be readily available, facing shortages, delays and drawing the attention of regional authorities.