rb bertomeu S.L.
Date: October 2001      Updated  June-2002


When fuel oil is used in Diesel engines, several residual compounds are formed, including Sodium Vanadates, which are highly corrosive as they are in a liquid state at temperatures of between 350º and 650ºC, according to the molar ratio of Vanadium to Sodium of the compound formed (See Dossier rb, Section B , page 8).

As has been amply explained in our technical documentation on the subject of corrosion, during the combustion of fuel oil the presence of these Sodium Vanadates causes corrosion at every point of the exhaust gas circuit of a Cogeneration Plant, wherever the temperature is in excess of 340º - 350 ºC, and the effect is ever more damaging the higher the content of vandates and the higher the temperature.


This phenomenon is the cause of corrosion on:


-         The Exhaust Valves of the engine

-         Turbos

-         Heat exchangers of the related boilers where the temperature of the inlet gases is usually between 350ºC and 390ºC, or even slightly higher.         


These corrosive effects are produced when the engine is warm, i.e., while the engine is running continuously, and can be more severe on the heat exchangers  if the engine is stopped repeatedly, given that at standstill, in addition to corrosion by vanadates, there may occur corrosion due to acidity of the encrusted residues, mainly produced by the presence of SO3 in the residues which gives rise to corrosive sulphuric acid below 160ºC.


The additive rb bertomeubeco F1/ASF has been demonstrated to be fully effective in neutralising all these effects of corrosion, and no other additive is able to guarantee the same tried and tested results.


The treatment of fuel oil with our additive “rb bertomeubeco F1/ASF works on two basic factors during the combustion of fuel oil:


a)   It changes the composition of the Vanadates, thereby raising their melting point and eliminates their corrosive effect at the operating temperatures of valves, turbos and boilers.


b)   It minimises the catalytic effect that Vanadium from the fuel oil has in the oxidising of SO2 into SO3, and thereby reduces the presence of SO3 in the exhaust gases and consequently the liability of the formation of corrosive sulphuric acid as the temperature drops.


For more information, please read the document "RB-8 Anticorrosive efect of the heavy fuel oil additive “rb bertomeu” beco F1/ASF"

Both these factors are key the prevention of corrosion on exhaust valves, on turbos and on the exhaust gas side of boiler heat-exchangers in power plants with Diesel engines running on fuel oil, both when the engines are running, and during standstill when the engines are not in continuous operation.


We have checked the operating logs and incident reports available in our database which relate to cogeneration plants running on fuel oil that regularly use our additive rb bertomeubeco F1/ASF and we have not found a single plant where corrosion has occurred on the turbos nor on the steam boilers, while the valves have suffered only the slightest of superficial corrosion which is removed at engine overhauls. This means the life in service of these components is tripled, as measured against installations where beco F1/ASF is not used.


For more information, please read the study "Minera de Santa Marta power plant. Valve savings historical data."



Equally, to give a common example about the extension on the TBO (time between overhaul) of an engine exhaust valves until doubling the normal value, we can mention the tests, carried out in collaboration with the plant owner and the engines manufacturer , along 2000-2002, in a power plant equipped with engines Deutz BV 16M 640 running on fuel oil (See our report RB-13 Energyworks-Carballo extension of the useful life of exhaust valves up to doubling TBO (Time between overhauls) ). Most relevant data of that test are the following :


            Beginning of tests        :           2000

            End of tests                 :           2002

            Engine power               :           6.3 MWhe

            Fuel                            :           heavy fuel oil

            Fuel additive                :           "rb bertomeu" beco F1/ASF 


            Exhaust valves installed in the engine for the tests           :           New                 :    6   (18.75 %)

                                                                                                          Reconditioned  :  26   (81.25 %)


            Reached  TBO :           203 %  of normal TBO  (normal TBO + 103 %)

            The test was given as concluded when the objective of doubling normal TBO was reached.


            Exhaust valves changed during the test, between TBO      0 %  and TBO 150 %   :     0

            Exhaust valves changed during the test, between TBO  150 %  and TBO 203 %    :     3


            Reusable exhaust valves at the end of tests       :           31  (96.8 %)

            Non Reusable exhaust valves at the end of tests :             1  (  3.2 %)


The comparative analysis of the differences in corrosion which exist between engines and boilers in cogeneration plants that regularly use our additive for fuel oil  rb bertomeubeco F1/ASF and other similar plants that either do not use treatment for fuel oil or an inferior treatment, are worthy of several comments of a general nature:


a)      In power plants where the additive rb bertomeubeco F1/ASF is used there is no corrosion detectable on the heat exchangers of the boilers nor on the turbos. The slight corrosion on the exhaust valves has been discussed in previous studies and is very much lower than that found where our additive beco F1/ASF is not used.


b)      The absence of corrosion, when our treatment is applied, is based on the elimination of corrosive vanadates at relatively low temperatures (340-380ºC) that are present in turbos and boiler heat exchangers (higher on the exhaust valves of the engines) as well as on reduction to a minimum of the oxidisation of SO2 into SO3.


c)      In power plants where our  treatment for fuel oil is not used, although we do not have operating data at our disposal, we do have considerable experience contributed by our customers who have turned to using our additive beco F1/ASF after finding corrosion at various points of the exhaust gas circuit, mainly on exhaust valves and turbos. The following are some of the more relevant comments:


1-   In practically all the engines substantial corrosion appears on the exhaust valves. The degree of corrosion is such that many of the valves have to be replaced due to blowouts occurring before the general maintenance stoppage, and those that pass the complete TBO have such high levels of corrosion that the necessary adjustment is severe and means that the valve may only be re-used once or twice (four to six times when our treatment with beco F1/ASF is used).


2-   The fact that the valves in an engine affected by corrosion may be of a different material to those in other engines, or reconditioned valves (used previously in other engines and later corrected) ought not to suppose a significant difference in the occurrence of corrosion as detected in practice. In fact, in many of the engines using our treatment    rb bertomeubeco F1/ASF, reconditioned valves are used, while still complying with scheduled TBOs (or even higher periods of time). (Please read our techincal document RB-24 The additive “rb bertomeu” beco F1/ASF and the increment of the useful life of reconditioned exhaust valves, in diesel engines using heavy fuel oil )


3-   A blowout is basically severe corrosion on certain point of the valve seat, which may be due to defects in the rotocap or localised defects in the material of the valve, but may also be aggravated by a lower level of anti-corrosion protection in the treatment of the fuel oil, given that the corrosive vanadates formed in this case accelerate the corrosion triggered by such defects, and end in perforating or blowing out the valves before the TBO is due.


4-   Regarding possible corrosion on the boiler heat exchanger, we may say that if corrosion appears during continuous operation it means that the fuel oil is not being treated, or that the treatment used is not as effective as our additive beco F1/ASF, which has prevented all corrosion at this point, both in continuous operation and in discontinuous operation, wherever it has been used.


On the other hand, in some plants tests have been made with an additive of the type combustion finalizing or combustion catalyst in the flow of gases entering the boiler (in order to reduce soot and organic unburned residues which dirty the heat exchangers of the boilers) which would obviously encourage the oxidisation or complete combustion of the all the unburned or partially burnt compounds that may be present in the exhaust gases of the engines, e.g. hydrocarbons, carbons and CO, but also of SO2, which would oxidise to SO3 aggravating corrosion during stoppages with discontinuous operation. It has also been observed that the injection of certain types of additive causes greater dirtying of the boiler heat exchangers, defeating the object of cleaning them.


5-   In the case of newer co-generation Plants, with a few thousand hours in operation, corrosion on the turbos will not have been still detected at this stage in any of the engines, as corrosion develops over a longer period than on the exhaust valves. Our experience in this area, which we hope is useful to yourselves, is as follows:


5.1  Several of our customers with Cogeneration Plants have had to replace turbos or parts of them, when corrosion appeared after a relatively low number of hours in operation (12,000 – 14,000) , before applying our additive treatment for fuel oil.


5.2 The application of the additive “rb bertomeu” beco F1/ASF has eliminated corrosion on the turbos, as well as reducing incrusted residues. We have customers whose engines have reached over 40,000 hours in operation with the original turbos.


5.3  If the appropriate anti-corrosion treatment is not applied, corrosion on the turbos is inevitable, especially if corrosion has been detected on the exhaust valves and on the boiler heat exchangers, as the corrosive compounds present in the exhaust gases are the same and the temperatures are quite similar.




rb bertomeu S.L.

Technical Department

November 2015


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