Dr. R. Vis, Director, Viswa Lab. Image Credit: Viswa Lab
We had earlier reported that we had subjected the scrapings from seized fuel pumps of vessels using the Houston area bunkers to FTIR analysis. We noted the presence of large quantities of acids and organic nitrogenous compounds. We were not completely satisfied with these results and wanted to carry out more detailed analysis to help us in tracing the source of the contamination.
We have now completed the pyrolysis GCMS analysis of the scrapings obtained from fuel pump plungers. Here are our findings.
From 100 to 300 degC, a large number of acidic substances, light to heavy acids including acrylic acids was noted. Phenols and other oxygenates were also identified
From 300‐650 degC, we noted a lot of Nitrogenous substances possibly extraneous and added to the bunker fuel. It is interesting to note that one of the nitrogenous compounds found in the pyrogram is used as a stabilizing/short stopping agent in storage of various monomers especially acrylic acids.
In our opinion, the contribution of 4‐cumyl phenol towards the sticky problem is, at best marginal
Based on the above and other results obtained during additional tests recorded earlier we would like to conclude as follows.
Presence of 4‐cumyl phenol in a small quantity is acknowledged in one of the problem bunker samples. However, the contention that it helps in epoxy resin formation (a sticky substance) is not confirmed since other epoxide monomers which should have been present are not seen.
In our opinion, the contribution of 4‐cumyl phenol towards the sticky problem is, at best marginal.
Houston has a concentration of petrochemical plants and there are multiple waste streams from literally hundreds of chemicals in these plants. We are therefore not able to identify a single source for the contaminants found. Our findings so far:
Multiple Acids ‐ The source of these acids could be products from waste biodiesel, TOFA (Tall Oil Fatty Acids), Seed Oil Fatty Acids etc.
Multiple nitrogenous compounds – These are possibly from polymer production (found in the material scraped from fuel pump).
The pyrolysis of the sticky resinous substance identified both organic acids and Nitrogenous compounds. This same pattern was also found in the FTIR carried out on the sticky resinous substance.
C12‐ C18 acids are seen in the bunker fuel samples and these samples also have high TAN (Total Acid Number). These could be from waste biodiesel, TOFA, Seed oil Fatty acids etc.
Our conclusion is that multiple waste products from multiple sources have been collected and have been introduced into bunker fuel as cutter stock. This cutter stock material would have assisted in reducing the viscosity of the bunker fuel and that too at minimal cost.
The only way to completely unearth this mystery is to make the supplier of this fuel provide the sample of the cutter stock, which they must be retaining, and also a truthful statement about the source of the contamination. It is possible that they themselves may not have known the composition of the cutter stock; but the source from which they have purchased would certainly know.