Experimental Test Series with Octamar BT-8

Transcription

1 Stability of MGO/HFO Mixtures Turbiscan method : ASTM D The principle of the test is to destabilize a sample of heavy fuel oil diluted in toluene by the use of heptane. The kinetic of asphaltenes flocculation is estimated by a turbidity meter which measures the light transmittance each minute during 15 minutes. The mathematical treatment of the recorded data allows the definition of an index the Separability Number - which is a precise indication of the asphaltenes dispersion state in the tested sample. This state of dispersion strongly influences diverse aspects of the behaviour of the fuel in engines and boilers, provided that they are sensitive to the size of agglomerates (sludge in the storage tanks, fouling of fuel filters and deposits on fuel injection equipment). The S.N. (Separability Number) is a feature of particular interest for the fuel oil from visbreaking processes. The values of S.N. are situated between 0,2 and 14 in almost all cases : S.N. between 0 and 5 : the measure reflects a good asphaltenes peptisation state. The fuel oil is considered "stable". S.N. between 5 and 10 : this level of S.N. indicates a risk of fast drift towards higher values if the storage conditions predispose to a further agglomeration process (time, temperature). S.N. up to 10 : the method reveals a very degraded asphaltenes peptisation state, conducing in operability problems already mentioned above. Experimental Test Series with Octamar BT-8 Samples : 1 : Fuel Oil - BB : Gasoil BB Treatment to investigate : A : Sample 1 B : Sample 1 treated with 100 ppm BT-8 C : Blend 70 % sample 1 / 30 % sample 2 D : Blend 70 % sample 1 / 30 % sample 2 treated 100 ppm BT-8 E : Blend 65 % sample 1 / 35 % sample 2 F : Blend 65 % sample 1 / 35 % sample 2 treated 100 ppm BT-8 G : Blend 60 % sample 1 / 40 % sample 2 H : Blend 60 % sample 1 / 40 % sample 2 treated 100 ppm BT-8 Page 1 of 8

2 Stability of MGO/HFO Mixtures Results The results are presented in graphs and Separability Numbers have been calculated from three repeatable tests. All samples were prepared with a dilution ratio equal to 1:5. A B C D Page 2 of 8

3 Stability of MGO/HFO Mixtures E F G H Page 3 of 8

4 Stability of MGO/HFO Mixtures Calculated Separability Numbers Experience Sample Treatment Dosage (ppm) Separability Number 1 A 1 - HFO / / B 1 - HFO BT C 70 % HFO / 30 % MGO / / D 70 % HFO / 30 % MGO BT E 65 % HFO / 35 % MGO / / F 65 % HFO / 35 % MGO BT G 60 % HFO / 40 % MGO / / H 60 % HFO / 40 % MGO BT Average is calculated from 3 Turbiscan runs. Page 4 of 8

5 Stability of MGO/HFO Mixtures Conclusions / Comments Analysis of the HFO sample without treatment shows a very degraded asphaltenes peptisation state (S.N. > 10), conducing in operability problems as sludge formation, filters fouling, cokage of atomisers Treatment of this sample by 100 ppm of BT-8 conduces to significantly improve the asphaltenes peptisation state (S.N. < 1). The fuel is stabilized and operability problems are not susceptible to appear. Analysis of the s (70/30, 65/35 and 60/40) shows that incorporation of gasoil has no effect on the stability of the fuel oil (S.N. still up to 10). The treatment of the s by 100 ppm of BT-8 conduces to significantly improve the asphaltenes peptisation state (S.N. < 1). The s are stabilized. Experimental Test Series with Octamar BT-25 Samples : 1 : Fuel Oil - BB : Gasoil BB Treatment to investigate : A : Sample 1 B : Blend 1 (90 % sample 1 / 10 % sample 2) treated 40 ppm BT-25 C : Blend 2 (70 % sample 1 / 30 % sample 2) treated 40 ppm BT-25 D : Blend 3 (50 % sample 1 / 50 % sample 2) treated 40 ppm BT-25 E : Blend 4 (30 % sample 1 / 70 % sample 2) treated 40 ppm BT-25 F : Blend 5 (10 % sample 1 / 90 % sample 2) treated 40 ppm BT-25 Results : The results are presented in graphs and Separability Numbers have been calculated from three repeatable tests. All samples were prepared with a dilution ratio equal to 1:5. Page 5 of 8

6 Stability of MGO/HFO Mixtures A B C D E F Page 6 of 8

7 Stability of MGO/HFO Mixtures Calculated Separability Numbers : Experience Sample Treatment Dosage (ppm) Separability Number 1 A 1 - HFO / / B 1 90 % HFO / 10 % MGO BT C 2 70 % HFO / 30 % MGO BT D 3 50 % HFO / 50 % MGO BT E 4 30 % HFO / 70 % MGO BT F 5 10 % HFO / 90 % MGO BT Average is calculated from 3 Turbiscan runs Page 7 of 8

8 Stability of MGO/HFO Mixtures Conclusions / Comments Analysis of the HFO sample without treatment shows a degraded asphaltenes peptisation state (S.N. > 10), conducing in operability problems as sludge formation, filters fouling, cokage of atomisers Treatment of different HFO / MGO s by 40 ppm of BT-25 conduces to significantly improve the asphaltenes peptisation state (S.N. < 1). The fuel is stabilized and operability problems are not susceptible to appear. Results from experiences D to F should be interpreted with precaution due to the big proportion of gasoil incorporated in the s. Indeed, Turbiscan analysis is inappropriate if asphaltenes content is less than 2 % in the. Under this limit, the measurements cells are less effective to detect the destabilisation (if baseline is up to 40 % = fuel inappropriate). Page 8 of 8