Now, what can we tell from this graph? If you are using an isobutane/propane mix your stove will keep working for a bit longer. To make matters worse, both the Powermax and the Kovea canisters hit zero gas flow around -24 C, so just getting the stove started might be very difficuult for said Canadian! Some tests are run at even higher temperatures. Not considered here is the fact that as the fuel evaporates inside the canister the remaining liquid fuel is losing energy and getting colder. Butane burns hotter than propane as it has a higher boiling point of -2ᵒC compared to propane at -42ᵒC. Propane keeps working in cold weather, when butane doesn’t. Comparing isobutane vs butane each have 4 carbon atoms and 10 hydrogen atoms (C, The difference between n butane and isobutane (isobutane vs butane) is minimal. Pure propane maybe? What is clearly evident here is the significant effect caused by changes in propane percentage and whether the canister has butane or isobutane. So, isobutane is a slightly better choice in cold weather but propane is the best at -42°C (-44°F). When the product label lists "hydrocarbon" as the propellant, it is often butane or isobutane. The resulting liquid will look similar to pure liquid butane for instance. If you have 80% butane in the liquid, the partial pressure of the butane vapour will be 80% of the nominal VP - what it would be for pure butane. My understanding is that all gas canisters must be able to take at least 50 C without any damage at all in order to pass the relevant European and American Standards. This would typically occur if the ratio of oxygen to butane was insufficient. (Manufacturing tolerances allow up to 6% n-butane, but this is minimized as much as possible and typically falls below 2%.) 4. The first is boiling temperature, at -42° for propane vs -0.4°C for n butane. I have had some long email discussions with a couple of experts in this area. All positions and orbits are all filled in both n-Propane and n-Butane, which is why they are called fully saturated. LPG (propane) vapour pressure is about 4x that of butane, at a given pressure. This is an example of a situation where propane stoves are preferred over butane stoves. 3. What we find is that we have a changing situation. So the partial vapour pressures are not changing over time. Let's take -5 C as a working temperature. If it feels cool to mildly warm, that's OK, but I keep an eye on it. While there are many similarities between these gases, there are also subtle differences. Thought 17 percent was acceptable, but i think they are sneaking up to 33 percent. All are liquids under pressure or below their different boiling points, -42°C for propane and -0.4°C for butane. Propane is better for cold weather with a lower boiling point, at -42°C vs -0.4°C for butane. Vapour pressure is probably the biggest difference between isobutane vs butane. The flame temperatures of butane and propane are virtually identical. I distinguished between 'mixture' and 'solution' in the stoves pages. May 5, 2019 #4 growingforfun said: I'd assume propane isnt used for a good reason, if it was easy and safe to use I assume everyone would because it's so cheap. Propane is classified as LPG – Liquefied Petroleum Gas – along with butane, isobutane and mixtures of these gases. Both are classified as LPG. Considering isobutane vs propane, 310.9 kPa is the vapour pressure of isobutane vs propane at 858.7 kPa (both at 21ºC) . One of the other important differences between the two gases is vapour pressure. i am in the gas industry and sell butane propane isobutane all things related toextraction. 310.9 kPa is the vapour pressure of isobutane vs butane at 215.1 kPa (all at 21°C). What this graph does show is that when you change from butane to isobutane the concentration of the (iso)butane does rise a bit. anyone that needs butane please let me know. In scientific nomenclature, "butane" refers to the n-butane isomer of butane vs the isobutane isomer. BHO all the way..my toes curl in the wrong way when I think of the propane taste in the oil, wax etc. While both propane and butane are environmentally friendly fuels, butane does have an extra carbon atom (C4H10 vs C3H8) that results in ⅓ more CO2 when burned. Vapour pressure is the force at which the gas pushes against the cylinder walls. The following is just what I do: I cannot accept any resposibility for what you do. Butane gas cylinders are suitable for indoor use, whereas, propane cylinders should not be used inside domestic dwellings. However, below -20 C things do get difficult even for liquid-feed gas stoves, even with the best of fuel mixes. Send any comments to the maintainer Roger Caffin. In fact the situation is more complex, but before we get into the details we need to spell out some basic science background. Actually, in warm weather I often add the radiation shield before I start cooking if I'm doing anything more than just make tea and coffee. Does all the propane boil off leaving all the butane? This is definitely a 'solution'. However, it still pays to keep the canister warm, as inspection of the graphs will show. Consider a canister driving an upright gas stove with a gas feed. If it is priced by volume — in litres — the butane has about 9% more energy content, with 27.5MJ/L versus 25.3 MJ/L for propane. All 3 can be liquefied under moderate pressure, stored and distributed in gas cylinders and other vessels. Both propane and butane, along with isobutane, are all hydrocarbon gases that fall under the broad label of "LPG", as they are all liquefied petroleum gases. It's the 'latent heat of vaporisation'. The bonding energies are so similar the molecules don't really care. To see what effect this has in the field, let's take the case from the first graph where the ambient is at -18 C: a very cold temperature for Australia. Both propane and butane are classified as LPG – Liquefied Petroleum Gas. Fuels such as petrol, kerosene and propane/butane are all 'mixtures'. Improved yields make it the preferred choice for greenhouse use. Reply. The poorest choice for cold weather, with a -0.4°C boiling point, is butane vs isobutane at -11.75°C. Problem is, I've never used propane. I've never used propane. Tricky stuff. Pro: By far the lightest and most compact/space-saving option. Both n-Butane (R-600) and i-Butane (R600a) are also used as refrigerants. The dashed green line represents atmospheric pressure at 3000 m. OK, we don't get that high in Australia, but never mind. Note that as a volume of liquid loses vapour it is losing the most energetic molecules, so the temperature of the remaining liquid will fall. Butane and isobutane are constitutional isomers meaning that they have the same chemical formula but different structures, physical and chemical properties. The liquid feed does not draw any sigificant amount of energy from the canister as the liquid is not evaporating inside the canister. But it takes energy to vaporise the butane and propane, and that energy comes mainly from the liquid. Both have 4 carbon atoms and 10 hydrogen atoms. Some people have claimed the fuels are solutions with a different specific boiling points. For obvious reasons, no odourant is added to the LPG when used as a propellant. It may actually be misleading to draw it as a line across the graph, but never mind. The boiling point temperature of n butane is -0.4°C. For many people, the different gases that qualify as LPG are indistinguishable and never pose an issue. It is the non-fuel applications, for propellants and refrigerants, where propane cannot be used instead of butane. They are commonly used as cooking fuels, particularly in portable camping stoves, according to Michael Hodgson, author of "Camping for Dummies." The carbon and hydrogen atoms are in a branch structure with isobutane vs n butane atoms in a continuous chain. If it starts to feel a bit 'hot' or above what I would call a comfortable hand temperature, I need to take some action to limit the thermal feedback: I may add the radiation shield. Butane is supplied to businesses that require Butane, as opposed to propane. You must log in or register to reply here. Note especially that the ratio of gases in this mix is changing as gas is drawn off: the amount of propane left is falling.