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How hot does Peat, Lignite, Bituminous Coal, and Anthracite burn? (self.askscience)
submitted 14h ago by leeofthenorth
It *should* be easy to just pop these into search engines and find the answer easily, but I'm on page 12 and *still* can't find an answer. For any of them. I've seen some more general coal burning temperatures, I find a number of ignition temperatures, but I can't find just how hot each of these can burn.
Edit: No, GPT is not a reliable source of information. Input the question 20 times and you get 20 different answers.
Edit: No, GPT is not a reliable source of information. Input the question 20 times and you get 20 different answers.
Coomb 9 points 12h ago
There is no specific answer to this question; certainly there isn't a single unique number.
For example, this study of 24 lignite samples from Turkey found ignition temperatures from 183°C to 276°C and peak temperatures from 340°C to 533°C. This is from samples all having the same mass, processed in the exact same way, provided with the same amount of oxidizer. (And no, the sample with the highest ignition temperature was not the same sample with the highest peak temperature.) Ignition and combustion temperatures are variable not only by overall category of coal, but by specific combustion conditions (especially how much oxygen/oxidizer is provided).
If you're asking for a specific reason, it would be easier to give you representative answers, but as you can see, at least for lignite, "burning temperature" spans nearly 200°C.
For example, this study of 24 lignite samples from Turkey found ignition temperatures from 183°C to 276°C and peak temperatures from 340°C to 533°C. This is from samples all having the same mass, processed in the exact same way, provided with the same amount of oxidizer. (And no, the sample with the highest ignition temperature was not the same sample with the highest peak temperature.) Ignition and combustion temperatures are variable not only by overall category of coal, but by specific combustion conditions (especially how much oxygen/oxidizer is provided).
If you're asking for a specific reason, it would be easier to give you representative answers, but as you can see, at least for lignite, "burning temperature" spans nearly 200°C.
cheses 1 points 8h ago
Are you sure the peak temperature is actually the temperature of the flame while burning? I cant read the paper, but it should be higher.
Coomb 2 points 8h ago
Peak temperature is perhaps more clearly referred to as "temperature at which the most rapid mass loss in the study occurred". The samples of coal were fired in a crucible beginning at room temperature with the crucible heated at 10°C per minute to 900°C (given a fixed oxidizer, which in this case was dry air). The rate of mass loss initially rises with temperature as water and very light volatile species are driven off; it then plateaus for some time. It then begins a sudden and rapid rise as combustion begins, and the peak temperature is the temperature at which this mass loss is largest. As combustion proceeds, less and less fuel is available to be combusted, until eventually the sample is reduced to ash and no mass loss occurs.
Are the peak temperatures representative of burning temperatures of the lignite? Well...maybe. The burning temperature of almost anything depends on a tremendous number of variables, including how the sample is prepared, what oxidizer it is exposed to, what the ambient temperature is, etc. That was most of the point: there is no single well-defined combustion temperature for almost anything flammable. There are adiabatic flame temperatures, but even these rely on assumptions about the amount and nature of oxidizer available for the reaction (e.g. dry air, pure O2, something more exotic).
Are the peak temperatures representative of burning temperatures of the lignite? Well...maybe. The burning temperature of almost anything depends on a tremendous number of variables, including how the sample is prepared, what oxidizer it is exposed to, what the ambient temperature is, etc. That was most of the point: there is no single well-defined combustion temperature for almost anything flammable. There are adiabatic flame temperatures, but even these rely on assumptions about the amount and nature of oxidizer available for the reaction (e.g. dry air, pure O2, something more exotic).
[deleted] -1 points 13h ago
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leeofthenorth [OP] 3 points 13h ago
Here's why you should not use GPT for research:
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The burning temperatures of different types of coal and peat can vary. Here is a general overview of the burning temperatures for peat, lignite, bituminous coal, and anthracite:
1. Peat: Peat is the lowest rank of coal and generally has a lower heat value compared to other coal types. The flame temperature during peat combustion typically ranges from around 600 to 900 degrees Celsius (1,112 to 1,652 degrees Fahrenheit).
2. Lignite: Lignite, also known as brown coal, is a low-rank coal with a relatively low carbon content and high moisture content. The flame temperature when lignite burns typically ranges from approximately 500 to 700 degrees Celsius (932 to 1,292 degrees Fahrenheit).
3. Bituminous Coal: Bituminous coal is a higher-rank coal with a higher carbon content compared to lignite. The flame temperature during bituminous coal combustion can range from approximately 700 to 900 degrees Celsius (1,292 to 1,652 degrees Fahrenheit).
4. Anthracite: Anthracite is the highest rank of coal and has the highest carbon content. It is known for its high heat value and low flame visibility. Anthracite can burn at flame temperatures ranging from approximately 900 to 1,500 degrees Celsius (1,652 to 2,732 degrees Fahrenheit).
It's important to note that these temperature ranges are approximate and can vary depending on factors such as the quality of the coal, combustion conditions, and other variables. The specific burning temperature experienced during coal combustion can be influenced by the coal's moisture content, volatile matter, fixed carbon content, and other properties.
Additionally, the heat output and efficiency of combustion for different types of coal can vary, with higher-rank coals generally producing more heat energy per unit of weight or volume compared to lower-rank coals.
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Also from GPT
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The burning temperatures of different types of coal and peat can vary. Here is a general overview of the burning temperatures for peat, lignite, bituminous coal, and anthracite:
1. Peat: Peat is the lowest rank of coal and generally has a lower heat value compared to other coal types. The flame temperature during peat combustion typically ranges from around 600 to 900 degrees Celsius (1,112 to 1,652 degrees Fahrenheit).
2. Lignite: Lignite, also known as brown coal, is a low-rank coal with a relatively low carbon content and high moisture content. The flame temperature when lignite burns typically ranges from approximately 500 to 700 degrees Celsius (932 to 1,292 degrees Fahrenheit).
3. Bituminous Coal: Bituminous coal is a higher-rank coal with a higher carbon content compared to lignite. The flame temperature during bituminous coal combustion can range from approximately 700 to 900 degrees Celsius (1,292 to 1,652 degrees Fahrenheit).
4. Anthracite: Anthracite is the highest rank of coal and has the highest carbon content. It is known for its high heat value and low flame visibility. Anthracite can burn at flame temperatures ranging from approximately 900 to 1,500 degrees Celsius (1,652 to 2,732 degrees Fahrenheit).
It's important to note that these temperature ranges are approximate and can vary depending on factors such as the quality of the coal, combustion conditions, and other variables. The specific burning temperature experienced during coal combustion can be influenced by the coal's moisture content, volatile matter, fixed carbon content, and other properties.
Additionally, the heat output and efficiency of combustion for different types of coal can vary, with higher-rank coals generally producing more heat energy per unit of weight or volume compared to lower-rank coals.
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Also from GPT
vee_lan_cleef 1 points 12h ago
While the temperatures it provides are not necessarily accurate, this statement is:
> The specific burning temperature experienced during coal combustion can be influenced by the coal's moisture content, volatile matter, fixed carbon content, and other properties.
And this is why you are having so much trouble trying to find exact numbers, because there simply aren't any in the same way there are for pure elements or compounds. Every source of peat or coal is going to be a little different, and even within the same sources there will be variability in combustion temperatures and overall stored energy.
> The specific burning temperature experienced during coal combustion can be influenced by the coal's moisture content, volatile matter, fixed carbon content, and other properties.
And this is why you are having so much trouble trying to find exact numbers, because there simply aren't any in the same way there are for pure elements or compounds. Every source of peat or coal is going to be a little different, and even within the same sources there will be variability in combustion temperatures and overall stored energy.
leeofthenorth [OP] 1 points 12h ago
There still should be a maximum that can be reached, given these all have ranges of carbon content and aren't just "anywhere from 0-100%".
Coomb 2 points 11h ago
Try to light a diamond on fire with a match, then compare that to trying to ignite some very finely ground coal dust. Actually, definitely do not do the latter.
What you would find is that the diamond wouldn't burn and that the coal dust would explode. This is despite the fact that the diamond has a higher (usually much higher) carbon content per unit mass than coal dust, even anthracite dust.
The point is that you have a massively underdetermined problem and there is no unique answer without a lot more detail in the problem statement.
What you would find is that the diamond wouldn't burn and that the coal dust would explode. This is despite the fact that the diamond has a higher (usually much higher) carbon content per unit mass than coal dust, even anthracite dust.
The point is that you have a massively underdetermined problem and there is no unique answer without a lot more detail in the problem statement.
ccdy 1 points 6h ago
You can calculate the adiabatic flame temperature for burning coal in air, which works out to around 2000-2100°C for various types of coals. This is a theoretical maximum that assumes complete reaction to chemical equilibrium (including the effects of dissociation), which is rarely achieved in practice due to both kinetics and heat loss. In practice you'd be much better off just measuring the actual temperature achieved by a particular experimental setup.
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