(Translated from original letter)


Belorado, 1st August 1998

Dear Sir,

In reply to your request, having reached 25,000 - 26,000 operation hours of 3 Deutz engines installed in our Cogeneration Plant in Belorado, we are pleased to express the satisfaction in our factory with the benefits obtained by the use of your rb bertomeu additive, which we have been adding to the fuel oil (n 1 Bia and n 1) for exactly 3 years (August/95 - August/98).


In addition to the already detected improvements regarding the reduction of fuel oil sludge, we would like to emphasise the following achievements observed and quantified during this period, regarding the conservation of the engine valves:

-    Total absence of corrosion in the inlet valves of the 3 engines, none of them having been replaced for this reason (only 3 have been changed because of mechanical misadjustment, which represents 3.1 % of the total installed)

-  Almost complete elimination of corrosion in the exhaust valves of the 3 engines, only 4 valves have been replaced for this reason (4.2 % of the total valves installed)

-   Notable total increase of the useful life of the exhaust valves, which practically doubles the value estimated by the manufacturer. Currently, 60% of the valves and 84% of the original valve baskets are in service, the remainder having been replaced gradually due to thermal fatigue or by not reaching the necessary minimum measures, as of approximately 20,000-21,000 operation hours.


Also, we would also like to express our satisfaction with the Technical Service that offer, especially referring to the inspections of the engines, whose technical and photographic reports constitute a valuable element for the follow-up and statistical control of the evolution of the maintenance of our engines.

We authorise the use of this letter for reference purposes.