Organic Chemistry - Ch 1: Basic Concepts (33 of 97) Petroleum Products (Part 1)

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Michel van Biezen

Күн бұрын

Пікірлер: 36

@aussiebloke5744 2 жыл бұрын

You have 2 propanes, C5H12 is Pentane.

@MichelvanBiezen 2 жыл бұрын

Thank you for pointing that out. 🙂

@shanehenry6066 2 жыл бұрын

I dislike being an online critic of your otherwise highly informative videos but the discussion about rocket ‘fuel’ @ 5:28 has some significant errors (aside from the already noted mistake regarding pentane). Although liquid oxygen (LOx) is often utilized as a propellant in bi-propellant rocket propulsion systems, it is an oxidizer. In air breathing engines the oxygen from the atmosphere is used as the oxidizer but this isn’t an option with rockets even at sea level because gaseous air is not sufficiently dense and only has a concentration of ~21% by volume, notwithstanding the drag and aeroheating that is produced by the intake of static air into a moving engine. Rockets have to carry their own oxidizers (sometimes oxygen, but also nitrogen tetroxide, red fuming nitric acid, high-test peroxide, and other more exotic oxidizing compounds) in order to be capable of achieving high velocity flight through the atmosphere and of course for exoatmospheric flight. Rocket fuels do, in fact, include petroleum distillates as ‘hydrogen donors’ including propane, methane, gasoline, and very commonly highly refined kerosene products (RP-1 in Western formulations,RG-1 and T-1 in many Russian and Chinese launch vehicles), as well as cryogenic liquid hydrogen. Hydrogen is often cited for its high mass impulse efficiency (specific impulse, Isp) although the low density, extremely cold temperature in the liquid phase at near-sea-level pressure, and tendency to escape from every possible leak point and form a readily-detonable cloud make it problematic for boost-stage engines (currently used on Delta IV, Araine 5 and SLS, and formerly on STS ‘Shuttle’ but generally eschewed otherwise.) Most boost stage modern rocket propulsion systems use petroleum distillates for their fuel, and despite the oft-repeated description of a rocket engine being ‘a controlled bomb’ it is a combustion process essentially identical to that which occurs in an internal combustion engine, although instead of doing work by expanding and pushing on a reciprocating piston, it “pushes” against the vehicle by being accelerated through a directional nozzle and then expanding in the diverging portion of a the nozzle ‘bell’ (for a de Laval nozzle), which transfers momentum from the accelerated and expanding exhaust to the ‘rigid’ body of the engine. Although petroleum distillates produce heavier molecular weight products and therefore a lower effective exhaust velocity (c*) and lower specific impulse (Isp), their storability, density (requiring less tankage), and specific thrust make them far more desirable for boost-phase propulsion. Please take a read through Sutton’s Rocket Propulsion Elements, chapters 2, 3, 6, and 7, and put together a lecture (or a series) on propellants in liquid rocket engines, which I’m sure would be of great interest to your subscribers as well as correcting the misapprehension here. I have very much enjoyed your series on planetology and this one which is refreshing my only occasionally utilized knowledge of O-chem, and I look forward to your future lectures.

@MichelvanBiezen 2 жыл бұрын

We welcome critique. Thank you for the input. 🙂

@pranavamali05 2 жыл бұрын

It has almost been 1 year learning from u thnku sir

@MichelvanBiezen 2 жыл бұрын

Glad to have you on board! 🙂

@akiko009 2 жыл бұрын

Jet fuel is very similar to diesel. In some ways one could say it's diesel with more stringent purity and consistency specifications.

@MichelvanBiezen 2 жыл бұрын

Nice insight into the nature of jet fuel. Thank you. 🙂

@sadammohamed7450 2 жыл бұрын

Kindly correct @1:29 I think you mean pentane. Thank you.

@MichelvanBiezen 2 жыл бұрын

You are correct.

@steffenleo5997 2 жыл бұрын

I recall the Jet A1 is a mixture from C10H22 until C16H34 with additive to increase the freezing point up to -50 Celcius Prof Biezen

@MichelvanBiezen 2 жыл бұрын

Good info. (see our previous comment).

@minhsiachen8186 2 жыл бұрын

Jet A-1's maximum freezing point is -47 degree C. -50 degree C and up to as low as -72 degree C freezing point is Jet B

@MichelvanBiezen 2 жыл бұрын

Thank you for this interesting information, 🙂

@dlrmfemilianolako8 2 жыл бұрын

Wow ! Chemistry is amazing 😀

@MichelvanBiezen 2 жыл бұрын

It is indeed! 🙂

@steffenleo5997 2 жыл бұрын

Good Day Prof Biezen, i think jet fuel Jet A1 is somewhere between gasoline and diesel oil. I read somewhere in aviation article long time ago. The exact chemistry formula i have forget.... Anyway these is a great video.... 👍👍

@MichelvanBiezen 2 жыл бұрын

Great comment. 🙂

@carultch 2 жыл бұрын

The term "jet fuel" is a performance spec, rather than an exact recipe or chemical composition. I had this exact question, when I wondered how it compares to Otto fuel and Diesel fuel. In general, it is a mixture of hydrocarbons ranging from octane to hexadecane. There are different variants based on the expected environment of the aircraft. Jet A1 fuel is the most common fuel class used today, while Jet B is the fuel class that is aimed for use in cold environments. I would expect that there are multiple recipes that the industry uses, with a sample of each tested to see if it meets the performance spec of desired class. Likely, the industry would follow economic forces and seasonal requirements to select one recipe over another.

@anglosaxon5874 2 жыл бұрын

Is it to do with the ceiling height of planes [going to much colder and higher parts of the atmosphere as well as the safety aspect]?

@MichelvanBiezen 2 жыл бұрын

I believe that the safety aspect is the primary aspect. They don't want jet fuel to be too flammable. Also off course, it needs to remain a liquid at very cold temperatures.