MARINELINE® & CHEMLINE® COATINGS FOR INDUSTRY

APC Article Reprints

London 2010 Product & Chemical Tanker Conference
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Speakers at the annual Product & Chemical Tanker Conference in London, which was held this past March 9 and 10, 2010, were of the same opinion about the immediate outlook for the tanker industry and for trade patterns: it is far too difficult to call. The two-day conference, which received the valuable support of the International Parcel Tankers Association (IPTA), was subtitled: Gaining the Edge in a Tough Market. Those speakers who addressed the issue of the tanker market certainly gave some idea of the difficulties that operators are likely to experience, at least for the next three years.

The presentation by Martin Kilroe, European sales manager for Advanced Polymer Coatings (APC), did offer some technical ideas that could help chemical and product tanker operators avoid some safety-critical operations. Shipowners look for a strong return on investment from their tank coatings, Martin said. They want the coatings to help make tank cleaning easier and quicker, reducing downtime, and offer versatility in the range of cargoes that can be carried. They want assurance that cargo will be carried from load port to discharge without contamination; application of tank coatings that is done correctly; and ongoing management that is relatively easy.

APC developed the MarineLine coating for chemical tankers. At the SMM exhibition in Hamburg in 2006, APC announced the 100th application of MarinLine and the following year the company completed the expansion of its Avon, Ohio plant to deal with growing demand. By last year, more than 350 ships had been coated with MarineLine.

Guy Johnson of L&I Maritime, which was engaged by APC to investigate the impact of MarineLine coatings on cargo handling and tank cleaning between different grades. L&I identified two immediate areas for investigation: the absorption of penetrating chemical cargoes and their transmission to subsequent cargoes. The project is well underway, Guy said, and APC has been encouraged to publish the interim results in the near future. L&I is in the early stages of a second project, looking at the ‘cleanability’ of MarineLine compared to other tank coatings. Initial results are interesting, he said.

Different coatings have different characteristics and advantages, which always need to be taken into consideration when planning a tank cleaning operation. Organic coatings tend not to absorb viscous, oil-based cargoes but do absorb and retain solvent-type cargoes. Inorganic zinc silicate-based coatings are porous and will absorb but not retain solvent-type cargoes; viscous cargoes can become ‘stuck’ in their profile. Stainless steel is extremely versatile but has some limitations.

L&I’s approach was to compare MarineLine 784 with stainless steel, an aged zinc silicate, a standard phenolic epoxy and a high-solids phenolic epoxy. Test panels of each coating were immersed for 48 hours in a range of cargoes and then cleaned according to the Dr Verwey tank cleaning guide and ‘wall washed’ with methanol. Any contamination of the surface of the test panel would be washed into the methanol, which was then screened in a spectrometer. The hypothesis was that the test panels with the cleanest wall wash samples could be considered as the easiest to clean.

The tests have so far confirmed the current understanding of the behaviour of the different types of coating. The results for stainless steel and MarineLine were very close in most cases. The tests also suggest that tanks are being ‘overcleaned’ in many cases and more efficient tank cleaning procedures can be investigated.

So far, Guy said, the project has confirmed that MarineLine does not seem to absorb penetrative chemical cargoes, nor does it allow viscous oilbased cargoes to stick to its surface. In other words it possesses benefits of both inorganic and organic coatings. It will be interesting to see if the full results of these studies are available in time for next year’s Product & Chemical Tanker Conference. The organisers Navigate Events and IPTA are already making plans.