It is difficult to adopt this fuel for the Otto engines, as the cycle dictates the fast burning . which is very difficult to be achieved using the Naphtha. However, you can prepare such fuel to suit the needs of the S. I. engines.

Thank you Saqaff.

But your answer is not clear. Can you explain more please?

The S. I. engines need almost homogeneous fuel air mixture, to be introduced at the suction stroke. Therefore, a special arrangement and modification are needed to carryout this preparation process, it might include preheating, atomization of the fuel, ...hot compressed air...

Naphtha has very low octane number ( RON of 70 or less). Modern SI engines cannot be run on such low octane fuels because of knock

Thank you Gautam. But I did a piece of research on using Naphtha in SI engine. I found that adding 7 vol.% of methanol to Naphtha enhances the engine performance and reducing emissions even better than using gasoline as fuel. Also, I measured the noise of the engine and I found that at this percentage the noise is lower than the noise generated when using Gasoline.

What do you think?

I would be grateful if I can hear your comment.

It depends on what the specification of the engine was. What was the compression ratio? Adding methanol increases the fuel octane number and will allow you to run the engine on higher load if the engine is knock-limited- noise reduction might also be related to better knock resistance. As for emissions - there might be slight reduction in HC and CO but an increase in knock. As for the other answer above - naphtha is in the gasoline boiling range and mixture preparation should be no different from gasoline.The burning velocity would also be similar. More details about fuel effects on engine combustion, knock and performance are in my book "Fuel Engine Interactions", SAE International 2014 (http://books.sae.org/r-409/)

As for emissions - there might be slight reduction in HC and CO but an increase in knock. The last word here should be NOx not knock

Thank you for your comment...

Even I did not measure the NOx but I think It will be lower due to the high heat required to evaporate the methanol which makes the temperature lower than of gasoline case.

However, do you think it is better to use this blend instead of gasoline if this blend has (almost) the same properties of gasoline?

I think naphtha is cheaper than gasoline and we do not need to other processes to convert naphtha into gasoline which means lower CO2 emmision and low power consumption.

Thank you again and I would be grateful if I can hear your reply.

Yes. Naphtha is less processed than gasoline and hence "easie"r to make. Then it depends on the availability and ease of manufacture of methanol. You also have to remember that methanol has a very low volumetric energy content (km/liter will go down) and has materials compatibility problems. It is also toxic and this raises handling issues for market deployment.

Thank you for your reply.

Actually, I disagree with you. Addition 7% methanol to naphtha improve the fuel quality, combustion process and will decrease the fuel consumption. Regarding methanol toxicity, I think the advantages gained outweigh this disadvantage. As I mentioned earlier, I did a research on this topic but I had no hi-tech lab to study all factors that were affected by adding the 7% methanol. You can see what I got from this study in the attached file.

Also, I will be happy if you can do a piece of research on this topic because I think it deserve the trial and I think you have good facilities(lab) to do it.

Thank you again.

what is average percentage of naphtha and gasoline can be distilled out from crude oil in over all world ?