Archoil AR6915 minimizes smoke emissions on MS Prinsengracht
Dutch Rederij Cement Tankers reports a clear and visible reduction in smoke emissions coming from the CAT 3408 engine exhaust. Already after a week of the introduction of Archoil AR6915 diesel fuel additive in the engine, the first results are there. Reduction in fuel consumption and emission reduction are the main aims of the company and is the reason why RCT choose to run on Archoil AR6915.
Whoever you talk to in shipping, captains, engineers, owners, maintenance companies, there is always something new. Every discussion adds to the vast database of knowledge we share with eachother. It also brings mutual goals to the surface. Especially relevant today are cost-reductions without investing money and reducing smoke emissions. Here we reach the grounds of fuel and oil-additives. Let us take you through the technology behind it, so you can benefit too.
For fuel additives we can say: The less compex they are, the better they will work. Basically cetane-boosters in combination with combustion catalysts bring the best results.
The overall quality of diesel fuel we bunker today is dependent on a number of factors. These include BTU value, viscosity, pour flow point, aromatic and paraffinic content. A diesel fuel’s quality also is very dependent on its cetane number. Smoke emissions and fuel economy as an outcome also depend on these factors.
The cetane number (CN) is an index of the ignition point or combustion quality of diesel fuel. We measure this using an ASTM D613 test. Standard European BS EN590 diesel as the major oil companies produce them normally has a minimum cetane number of around 51, with premium pump diesel a little higher. Depending on engine design, driving conditions, and so on, the optimum cetane value for most vehicles is around the mid to high 50s. Any value greater than 60 will not achieve any additional benefits. In most cases this will alter ignition timing to the degree that power is lost.
Matching cetane to the engine is important in order to maximise the engine’s performance. Diesel fuels, and biodiesel fuels in particular (especially the homemade brews) usually start with a much lower cetane number so cetane improvement for these fuels is essential. A fuel with too low of a cetane number for a particular engine will result in reduced cold-start ability, rough running, excess engine noise/vibration and reduced combustion quality. This leads to reduced performance. Also excess emissions, and carbon buildup throughout the engine and emission system components (intake, Emission Gas Regulation, Diesel Particle Filter, etc.)
A higher cetane fuel that is a proper match for the engine will reduce ignition delay and improve overall combustion quality. It will liberate more BTU (energy) from the fuel (so the feel of “more power”), and improve performance and fuel economy. It also will reduce engine noise, deposit buildup, and exhaust emissions.
What should I look for in a cetane booster?
Contrary to some propaganda, alkyl nitrates still offer the greatest improvement in cetane number, with measured increases of up to eight points. When it comes to alkyl nitrates, 2-ethylhexyl nitrate (2-EHN) is the most popular and most respected. It offers more consistent ignition quality whilst reducing unwanted and negative combustion conditions. Fuel additive manufacturers recognise both the benefits of boosting the cetane number and using 2-EHN so much now that most offer cetane improvers. The question in this case is what are you getting for your money?
From close examination it appears many cetane boosters contain useless fillers. To maximise profits most manufacturers still insist on the single bottle per tank philosophy. Some 200-300ml bottles that treat a single tank of fuel have as little as 20% active ingredients. This is lucrative for the manufacturer but not a good value for the consumer. Therefore, it is important to understand what you are getting for your money.
The optimum amount of 2-EHN is around 1:2000 per tank of fuel, depending on the engine and base cetane level. As 2-EHN can reduce lubricity it is important that a lubricant is also blended in. To ensure you are getting the best value, make sure the product contains 2-EHN as its base and a reasonable proportion of the remainder contains useful ingredients, such as lubricant, detergent, etc.
Increasing surface tension
Also increasing the surface tension of the diesel fuel adds to the equation. Less wear, less carbon deposition and fuel consumption are the benefits we aim for here. Compare the injected fuel droplets with a balloon that is pumped up to the max. This balloon will burst much easier than the balloon that was filled with air a day ago. So: higher surface tension = bigger bang. During the compression stroke the valves close and the pistons rise. Here, a droplet with a higher surface tension will burst into millions of nano-sized droplets, enabling a completer and evenly burn, thus reducing smoke emissions.
So what do we recommend and why?
Active cetane improvers are essentially a form of fuel modification, or more accurately, combustion modification. Especially, when combined with the correct fuel catalyst technology, latest nano detergents, and lubricity additives, they can turn the most mediocre pump fuels and biodiesels into super diesel that will outperform the best premium pump fuels.
How to start
Before you introduce any additive in your vessel’s engine: Make a base-line measurement. Check your logs, compare running-hours with consumption and position of the vessel (were you on a river, a canal, long-hauling, feedering etc.). Your cargo tonnage counts. Current, wind, draft, rain, ambient temperatures, etc. Check and document temperatures of engine, oil and exhaust. After that survey is made, run on an additive for at least 6 months and compare.
Please contact us for your fuel consumption protocol, so we can help you to get the results you want as early as possible.