Thermal Fluid System 18 months later: Cleaning out and preventing deposits with Nanotechnology
All organic chemical structures undergo thermal degradation as heat is applied. At any given elevated temperature there is some level of degradation that occurs depending upon the structure of a particular heat transfer fluid or oil. Non-aromatic versus aromatic chemical structures and then the degree of aromaticity determines the thermal stability ranking at increasing temperatures. This is what you know when operating a thermal fluid system.
Therefore, thermal fluid systems have their problems: Possibility of lowering flash-points. Carbon depositing on tubes insides. Corrosion of tubes due to acidic influences or insulation, to mention a few. During 2014, the thermal fluid system on board of vessel Stolt Pelican showed increasing carbon depositing on the insides of the tubular system. Along with that came an increasingly lowering flash-point of the thermal fluid. This is caused by increasing oxidation and polymerization. This on its turn is caused by the continuous steep heat changes, with heat peaks/lows varying 80C / 176 F and extern contamination of the fluid. Therefore, the 2000 liter system strongly needs tube replacement or thorough cleaning. Either way, the system is facing a shut-down and some clean-out work, thermal-fluid replacement and possible tube renewals. Or?
Provide a solution that will do the following:
- Remove scale and carbon build-up from internals of pipes and tubes;
- Prevent system from plugging during the process as risk of releasing bigger parts of scale is present;
- Avoid situation that 2000 liters / 530 gallons of thermal fluid needs to be replaced;
- Avoid stop of the system caused by disturbance of pumps, filters, exchangers;
- Prevent system from future carbon build-up;
- Condition fluid on flash-point level and TAN (Total Acid Number) remains stable for life time cycle of fluid.
Archoil AR2100 Nanoborate Thermic Oil Treatment was introduced into the system at a 1:10 treatment ratio to the expansion tank of the 2000 liter / 530 gallon system during operation of the system. AR2100 was not pre-heated. As plugging of the filters and pumps caused by large chunks of scale needed to be avoided, introduction of Archoil AR2100 to the system during operation is advised. This is to be done during one full loop of the fluid. So: 2,000 liter system pumps 500 liters an hour: 4 hours needed to introduce AR2100 to the system, etc.
Why Archoil AR2100:
AR2100 is made up of three ester groups and a nanoborate friction modifier. The lanolin ester is the main cleaning agent. Its function is to impregnate the surface of varnish and coked-up deposits.
The second is an aliphatic ester. It provides better film forming of the host oil, eliminating the potential of dry spots in the oiling system during the cleaning process. This component is also very resistant to oxidation. AR2100 is a supplement to the host oil while contaminants are being removed and deposited in the filters.
The last ester is a biodegradable, polyol ester, which provides extreme pressure capability to the host oil. Utilizing heat, pressure, and flow generated within the oiling system, AR2100 safely and effectively dissolves deposits. Because these deposits were formed slowly over time; they should be cleaned/removed slowly and methodically.
Nanoborate in an ester matrix base compliments its sister esters assisting in cleaning and forming a uniform new surface into the metal alloy filling in all asperities and creating an extremely low coefficient-of-friction of 0.037% This near frictionless surface protects against further carbon buildup.
The ester combination provides polarity to the host oil, giving the thermic fluid an attraction to metal surfaces reclaiming these surfaces from contamination and maintaining them from further contamination.
After 18 months of introducing and running the system on board of vessel Stolt Pelican, the vessels superintendent and nC Surface Technology’s CTO Rob van Hoorn evaluated the results of the project in March 2016.
- Removing scale and carbon build-up from internals of pipes and tubes: Pass, good result.
- Prevention of system from plugging during the process (risk of releasing bigger parts of scale is present): The first 2 weeks strainers before the circulation pumps needed extra cleaning, as system released carbon build-up. Some sediments came loose after 2 weeks after adding AR2100.
- Avoid situation that 2000 liters / 530 gallons of thermal fluid needs to be replaced: Systems’ fluid was kept and topped up with 400 liters fresh oil after two weeks as some fluid was lost during maintenance.
- Avoid stop of the system caused by disturbance of pumps, filters, exchangers: No stop made during project.
- Prevent system from future carbon build-up: No carbon build up detected so far.
- Condition fluid on flash-point level and TAN (Total Acid Number) will remain stable for life time cycle of fluid: Fluid remains in stable condition since introduction (Sep ’13) of Archoil AR2100.
Conclusion of superintendent is that this solutions has been cost-effective and satisfactory.