Bifunctional Heterogeneous Catalyst for Biodiesel Production from Waste Vegetable Oil
, Vincent Okudoh 2 and Oluwaseun Oyekola 1,*Round 1
Reviewer 1 Report
I really enjoyed reading this article. It is well written and is very interesting.
I would like to suggest to be published in the Special Issue "Biomass Energy and Biomass as a Clean Renewable Fuel " because it fits perfectly in the subject.
As for recommendations, I can suggest the authors to:
1) In the abstract must highlight the importance of the subject for the development of the state-of.the-art of biodiesel production.
2) In the introduction must do the same. Just include a short paragraph highlighting this importance to the technology, to the market and to the development of cleaner productions.
3) I would like to read something about this evolution concerning other non-convencional raw materials used in biodiesel production.
4) The quality of the figures can be improved. Include a legend in figure 1.
5) Figure 3 is irrelevant. If not, must explain the importance in plain text and must have a legend or dome indication of what is what.
6) Improve conclusions and highlight the importance of the results.
Good work.
Author Response
Point 1: I would like to suggest to be published in the Special Issue "Biomass Energy and Biomass as a Clean Renewable Fuel" because it fits perfectly in the subject.
Response 1: We have no objection at all regarding the inclusion of the article in Special Issue "Biomass Energy and Biomass as a Clean Renewable Fuel ".
Point 2: In the abstract must highlight the importance of the subject for the development of the state-of the-art of biodiesel production.
Response 2: We have highlighted the importance of the subject for the development of the state-of the-art of biodiesel production (see lines 14-16 & 28-30).
Point 3: In the introduction must do the same. Just include a short paragraph highlighting this importance to the technology, to the market and to the development of cleaner productions.
Response 3: We have highlighted the importance of the subject to the technology, to the market and to the development of cleaner productions (see lines 52-57 & 124-127).
Point 4: I would like to read something about this evolution concerning other non-conventional raw materials used in biodiesel production.
Response 4: We have included the evolution concerning other non-conventional raw materials used in biodiesel production (see lines 52-57).
Point 5: The quality of the figures can be improved. Include a legend in figure 1.
Response 5: This has been addressed
Point 6: Figure 3 is irrelevant. If not, must explain the importance in plain text and must have a legend or dome indication of what is what.
Response 6: Figure 3 has been deleted.
Point 7: Improve conclusions and highlight the importance of the results.
Response 7: The conclusion has been improved (Lines 436-454).
Reviewer 2 Report
For FAME to be used as a biofuel for diesel engines, it must be a high purity fuel. For example, according to the European standard for Biodiesel EN 14214, the ester content of Biodiesel must be at least 96.5 5 (m/m). Therefore, achieving a conversion rate of less than 90% discriminates against such esters.
Was the temperature 65oC, was the temperature of the beginning of the reaction, was the reaction mixture heated to 65oC, and did it rise later (Ezgoenergetic reaction)? This is important because the methanol temperature is around 65 ° C. Therefore, if the temperature was higher, it was conducive to the speed and efficiency of the process, because methanolate in the gas phase reacts more efficiently and more methyl esters of higher fatty acids are formed.
I have some doubt about the accuracy of the results due to the insufficient amount of oil used for transesterification. The structure of sunflower or palm oil contains about 12% (m/m) glycerin. If 50ml of oil is used, it means that assuming 100% efficiency of the process, approximately 6ml of pure glycerin should be precipitated. With such a small amount, some could remain on the walls of the glass vessel.
I would suggest that you don't name all major products obtained as FAME. Or rather as it should be methyl esters of higher fatty acids. In contrast, FAME is used rather for high purity esters. In Europe, according to the vegetable fuel standard for diesel EN 14214, the ester content in esters must be at least 96.5% (m/m).
Suggests for the future not to describe in detail the research activities, as this is not needed. It is important that the test, whether the analysis of the parameters was in line with the standard on it. Chromatographic testing should be carried out, e.g. for parameters in Europe in accordance with the recommendations of the general biodiesel standard EN 14214, this should be done by the chromatographic method described in EN 14103.
As for the preparation of catalytic substances and the correctness of their implementation, I have no objections here. I believe that the research was carried out in accordance with current knowledge and principles.
Work is of great utilitarian importance.
I am commenting on the work for publication after taking into account my comments
Author Response
Point 1: For FAME to be used as a biofuel for diesel engines, it must be a high purity fuel. For example, according to the European standard for Biodiesel EN 14214, the ester content of Biodiesel must be at least 96.5 5 (m/m). Therefore, achieving a conversion rate of less than 90% discriminates against such esters.
Response 1: 98% FAME yield was obtained using waste sunflower oil, while a lower yield of 89% was obtained with waste palm oil. This was associated with the following “The total FAs content of WSO was lower (29.18%) compared to WPO (36.2%). Thus, WSO has a better potential as a feedstock for FAME production” (See lines 3601-363).
Point 2: Was the temperature 65oC, was the temperature of the beginning of the reaction, was the reaction mixture heated to 65oC, and did it rise later (Ezgo energetic reaction)? This is important because the methanol temperature is around 65 ° C. Therefore, if the temperature was higher, it was conducive to the speed and efficiency of the process, because methanolate in the gas phase reacts more efficiently and more methyl esters of higher fatty acids are formed.
Response 2: The temperature of the reaction was maintained at 65oC as the boiling point of methanol is 64.7 °C. This allowed the steady gas phase through evaporation to efficiently give the high yield of fatty acids methyl esters recorded at 98% in the study (see lines 212-216).
Point 3: I have some doubt about the accuracy of the results due to the insufficient amount of oil used for transesterification. The structure of sunflower or palm oil contains about 12% (m/m) glycerine. If 50ml of oil is used, it means that assuming 100% efficiency of the process, approximately 6ml of pure glycerine should be precipitated. With such a small amount, some could remain on the walls of the glass vessel.
Response 3: The glycerol or glycerine quantity was not considered in the calculation of FAME percentage yield, this is because the percentage of glycerine in the vegetable oil is constant which was removed at the end the reaction (Lines 225-231). Meanwhile our further studies will consider the medium to large scale of producing FAME from these two vegetable oils.
Point 4: I would suggest that you don't name all major products obtained as FAME. Or rather as it should be methyl esters of higher fatty acids. In contrast, FAME is used rather for high purity esters. In Europe, according to the vegetable fuel standard for diesel EN 14214, the ester content in esters must be at least 96.5% (m/m).
Response 4: As mentioned above 98% (m/m) was obtained for one of the candidate feedstocks.
Point 5: Suggests for the future not to describe in detail the research activities, as this is not needed. It is important that the test, whether the analysis of the parameters was in line with the standard on it. Chromatographic testing should be carried out, e.g. for parameters in Europe in accordance with the recommendations of the general biodiesel standard EN 14214, this should be done by the chromatographic method described in EN 14103.
Response 5: Thank you for the suggestion, we will consider that in our future studies.
Point 6: As for the preparation of catalytic substances and the correctness of their implementation, I have no objections here. I believe that the research was carried out in accordance with current knowledge and principles.
Response 6: Thank you for all your commendation, we really appreciate that.
