Historically, there has always been a lower price associated with the bunker market in relation to other petroleum products. This explains why refiners have tried to find new ways of minimizing the yield of residual oil and to use it as a catch-all for the heavy ends of various processing operations. In other words, the increased demand for lighter, more profitable fuels has focused interest on squeezing the most out of the residual oil or "bottom of the barrel". Being sold at poor returns, the bunker fuel oil is still manufactured, but the actual trend is toward reducing its consumption.
The residual oil produced by the straight run method, nowadays, becomes the input for further processing. In other words, the "RESIDUE" left over, after all the "goodies" are distilled, IS THEN BLENDED BACK, in most cases, WITH THE LEAST VALUABLE "cutter stock" available in the refinery to meet viscosity specifications.
Some of the additional processes include : thermal cracking, catalytic cracking, hydrosulphurizing, hydrocracking and cooling. All these processes have one thing in common : they all degrade the bunker fuel oil quality. THE END RESULT IS A FUEL THAT HAS A TENDENCY TO SMOKE AND WHICH REQUIRES MORE ATTENTION AND MAINTENANCE. In heavy fuel oil, these processes remove the solvent from the fuel oil, thus producing insoluble solids in suspension. In light fuel oil, the cracked products, added to a blend of straight run, contain more aromatic hydrocarbons which have a tendency to smoke with more olefinic hydrocarbons subject to oxidation or polymerizatlon with end results of gums and bacteria.
When vanadium and sodium are wrap up in the agglomeration of asphaltenes they are corrosive and cause many problem during combustion. This new distribution of a barrel of crude oil, between distillate and residual fuels creates problems unknown in the past, but which now must be faced by today's light and heavy fuel oil consumers.
As the quality of fuel diminished, fuel related breakdowns increased to a point where many users became alarmed. Thus, fuel oil ADDITIVES became the object of serious on-going research in order to reduce maintenance costs and energy consumption. Although research was carried on by the industry itself, many observers were skeptical as to the value of these products when they were first introduced. Even today, many still are. Metallic components used in the manufacturing of currently sold additives explain, partly, this lack of enthousiasm.
MOST OF THE ADDITIVES SOLD ON THE AMERICAN MARKET (more than 200 products) were tested by the U.S. Environment Protection Agency. All of them PROVED TO CONTAIN METALS OR METALLIC COMPOUNDS WHICH SIGNIFICANTLY REDUCE THEIR EFFECTIVENESS. The results of the study show that "the use of metallic additives causes a high concentration of metal compounds in the fuel gas, and the possible toxicity of these new emissions makes the use of these additives very questionable"(1). The results clearly showed that most of the metallic additives could not trigger real savings nor could they be efficient in reducing pollutant emissions.
In fact, METALLIC ADDITIVES generally ACT AS IGNITION DELAYERS in diesel fuels. Moreover, there is much evidence that metals, such as copper, zinc, manganese, iron and lead, when used in bunker fuels, may have harmful side effects on cylinder lubricant conditions. Finally, it has been shown that even a low concentration of lead in fuels promote high temperature corrosion of nickelalloyed materials used for exhaust valves in diesel engines. Existing data indicate that the presence of metals or metallic compounds in additives hinder substantially their effectiveness, as it can also affect adversely the lubricating qualities of the oil. Almost all fuel oil additives on the market contain metallic additions for various combustion improvement reasons. Since "CATAPHORE" CONTAINS NO METALLIC ADDITIONS whatsoever, THE PROPLEMS related to metallic compounds ARE TOTALLY ELIMINATED.
(1) Effects of Fuel Additives on Air Pollutant Emissions,
G.B. Martin, D.W. Pershing lt al, U.S. Environmental Protection Agency, June 1971.