Maximizing Gas Usage in 11kg LPG Cylinders for Cookers and Forklifts: Residual Gas & Flame Height

Hello. I have been using a gas cooker powered by an LPG cylinder for a year. I have already changed the cylinders several times and each time it is necessary to replace the cylinder, I have the impression that there is still gas at the bottom.

At work, I often replace similar cylinders in a forklift truck (specially adapted to them) and they are light and dry-cleaned. I have recently replaced the reducer and at the beginning the difference in the height of the flame was noticeable. Now, however, the flame is insufficient and there is still something floating at the bottom of the cylinder.

I would like to add that the cylinder lasts on average for two or two and a half months. We don't cook dinners on it. The stove is used to boil water in the kettle (6-10 times a day), maybe some breakfast and that's it.

I do not know if there is any way to extract these remnants or are cylinder users doomed to this type of loss? What do you think about it ?

What is left at the bottom is definitely gas? The only thing that can block is the reducer. There are cylinders that turn it upside down when the gas runs out.

Jerzykowski wrote:

What is left is not a gas but some undefined liquid.

They add water or oil to gasoline at petrol stations. Maybe the gas also "wants" something to earn extra?

Jerzykowski wrote:

And not extractable there. When I have such water left, I turn the valve down and it spills out.

And what are you doing with this "poured out"?
Perfume is not ...

dorfo wrote:

We don't cook dinners on it. The stove is used to boil water in the kettle (6-10 times a day), maybe some breakfast and that's it.

Boiling water on LPG is uneconomical. For PLN 30 you can buy the cheapest electric kettle and boil water cheaper.

Electric kettles are highly efficient, i.e. about 90% of electricity is used to heat water, while cooking with gas the energy is not used so well. We heat the water, pot, grate and the air surrounding the burner. In the electric kettle we will boil water faster. It is difficult to assess which source is more economical, because while calculating / measuring the consumed electricity is not a problem, but measuring the amount of gas consumed is worse. If someone has a gas meter, it simplifies a lot.

Walker29 wrote:

Besides, LPG or propane-butane?

Isn't that the same?

Exactly...?

Jaku*b wrote:

mirrzo wrote:

Walker29 wrote:

Besides, LPG or propane-butane?

Isn't that the same?

To the author of the thread: The gas should last until the very end. If you unplug the cylinder and loosen the valve, the rest of the gas will disappear. If the cylinder no longer hisses and something is still splashing inside, it is not gas.

It is exactly what is known as a fragrance to make you feel it when the gas is released.

if you pour it out, the stench won't leave you for a long time!

As for the remains in the cylinder, I think that the picture will explain a lot why there is always something left in the cylinder from the stove, and in those supplying vehicles, the cylinder is empty.

Gentlemen - weigh the cylinders empty and full!
I use "alleged" 11 kg cylinder for the stove at home
We have its tare weight on the cylinders - correct after emptying,
But I have already weighed 2 cylinders straight from the distributor (wrapped in foil, etc.) and unfortunately I find that the gas itself is there .... 5 kg
Another change awaits me in a few days - I will see how much will be in the next one

Walker29 wrote:

Gas in a cylinder at different temperatures has different weight, unfortunately

This is interesting. That other pressure is agreement, but mass?

12pawel wrote:

Electric kettles are highly efficient, i.e. about 90% of electricity is used to heat water, while cooking with gas the energy is not used so well. We heat the water, pot, grate and the air surrounding the burner. In the electric kettle we will boil water faster. It is difficult to assess which source is more economical, because while calculating / measuring the consumed electricity is not a problem, but measuring the amount of gas consumed is worse. If someone has a gas meter, it simplifies a lot.

It's interesting. I read a bit about it and opinions are divided. Some calculations show behind the cylinder, others behind the current. Why is it still not written out clearly?

dorfo wrote:

I would like to add that the cylinder lasts on average for two or two and a half months. We don't cook dinners on it. The stove is used to boil water in the kettle (6-10 times a day), maybe some breakfast and that's it.

11kg cylinder - 55 PLN. For 75 days it is 73 [gr / day]. You can buy 1.2 [kWh] of electricity for this. Translating into cooking it is 10 [l] of boiling water.

[quote = "Walker29"]

Quote:

What then happens to the mass when changing temperature and pressure?

Nothing, i.e. the mass of gas is constant in a closed cylinder as is the volume of gas there. And the pressure will depend on the temperature.

I just ran a little test, here are the results:
0.5l of water at room temperature, boiled in a kettle on an optimally selected burner.
Natural gas consumption is just over 0.013 m?.

The cost of this, taking into account the cost of gas and the variable network fee (a fixed one, I would pay anyway, so I omit it) is approximately PLN 0.4 per liter.

Has anyone done a similar calculation for the current?

Slowly the discussion deviates from the initial issue, so regarding the residue in the cylinder, I would like to add that there are also cylinders with pure propane on sale. It is not much more expensive, but has many advantages, such as cleaner exhaust gases and greater resilience, and no pollution with heavier fractions, which constitute a low volatility, i.e. unburned residue in the cylinders. It is worth checking at larger points of purchase or ordering pure propane cylinders.

rafk wrote:

I just ran a little test, here are the results:
0.5l of water at room temperature, boiled in a kettle on an optimally selected burner.
Natural gas consumption is just over 0.013 m?.

The cost of this, taking into account the cost of gas and the variable network fee (a fixed one, I would pay anyway, so I omit it) is approximately PLN 0.4 per liter.

Has anyone done a similar calculation for the current?

Measured - boiling 1.7 liters of water = 0.193 KWh
Calculated - heating 1.7 liters from 10 ° C to 100 ° C = 0.178 kWh

Propane-butane cylinder 11kg / 22 liters
46MJ × 11 kg = 506 MJ
506 MJ ÷ 3.6 = 140.55 kWh

GZ-50 gas
34 MJ / m?
34 MJ ÷ 3.6 = 9.44 kWh in 1 m3

jekab wrote:

rafk wrote:

I just ran a little test, here are the results:
0.5l of water at room temperature, boiled in a kettle on an optimally selected burner.
Natural gas consumption is just over 0.013 m?.

The cost of this, taking into account the cost of gas and the variable network fee (a fixed one, I would pay anyway, so I omit it) is approximately PLN 0.4 per liter.

Has anyone done a similar calculation for the current?

Measured - boiling 1.7 liters of water = 0.193 KWh

So 1 liter - 0.11kWh. At 65 [g / kWh] it gives 7.4 [g] for boiling a liter of water with electricity.