>>12446154>same as your logic that propane will cause sooting/coking under high pressure fuel rich combustion conditions>>12446145>you have no proofFine, I'll explain my logic, retard.
Take something we know is sooty, kerosene (aka RP-1). Generally RP-1 consists of a few long chain hydrocarbons, but I'll pick C12H26 as the average constituent.
Next look at something we know isn't sooty, methane. That's easy, CH4.
I will be considering 100% pure fuels in my argument, so don't come to me with "b-but take the sulfur out!!", there IS no sulfur in these fuels.
To understand why propane cokes, you need to understand why coking deposits form. Basically, under the temperatures of carbon-oxygen combustion, hydrocarbon molecules break down into various species of highly reactive radicals. The thing to know is, only the hydrocarbon radicals that have a sufficient number of hydrogen atoms still attached remain volatile gasses; get too many carbon atoms with too few hydrogens and the resulting radical acts more like elemental carbon, which as we all know has the highest sublimation point of any element.
Now, when methane breaks down, the species that can be produced are CH3, CH2, CH, and naked carbon. However, the concentration of hydrogen in the decomposition gas goes up even as methane radicals are losing hydrogen, and the net result is that carbon radicals never manage to break down all the way to pure carbon. Since even CH is a volatile gas, no coking deposits form.
In short form, RP-1 doesn't have enough hydrogen to prevent elemental carbon from forming, and worse some of the radicals produced can still have hydrogen yet not be volatile (say, C6H8 as an example). This leads to thick black tar deposition.
Look at the H to C ratio of each fuel. Methane has 4:1. Kerosene has 13:6. What does propane have? 8:3. In decimals, that's 4, 2.16, and 2.66 respectively.
Given that propane has a H to C ratio far closer to kerosene than methane, I predict it cokes.
