Thermodynamics - Burning Butane in an Oven

  • Context: Undergrad 
  • Thread starter Thread starter Astrum
  • Start date Start date
  • Tags Tags
    oven Thermodynamics
Click For Summary

Discussion Overview

The discussion revolves around the thermodynamics of burning butane in an oven, specifically examining how the ambient temperature affects the burning point of butane and whether it has a cooling effect in high-temperature environments. The scope includes theoretical considerations and exploratory reasoning regarding combustion and heat transfer.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the burning temperature of butane will increase in a heated oven due to reduced effects from surrounding air.
  • Others argue that burning butane is exothermic and will not have a cooling effect on the oven, suggesting it will only increase the oven's temperature.
  • A participant questions whether the initial temperature of the butane affects the overall heat dynamics in the oven.
  • Concerns are raised about the cooling effect of specific heat when cold butane is introduced into a hot oven, with calculations presented regarding the energy involved in heating butane.
  • Another participant notes that the combustion energy and specific heat values indicate that the cooling effect is negligible compared to the heat produced by combustion.
  • One participant discusses the implications of increased ambient temperature on the formation of combustion products, suggesting that higher temperatures may lead to incomplete combustion and affect flame temperature.
  • It is mentioned that at certain temperatures, reactants may not form products and could exist as plasma, indicating a complex relationship between temperature and combustion outcomes.

Areas of Agreement / Disagreement

Participants express differing views on whether burning butane in a hot oven can have a cooling effect, with some asserting it cannot while others explore the conditions under which it might. The discussion remains unresolved regarding the specific impacts of ambient temperature on combustion products and flame characteristics.

Contextual Notes

Participants highlight that the burning temperature of butane is typically defined under standard atmospheric conditions, and the effects of varying oven temperatures on combustion dynamics are not straightforward. The relationship between temperature and combustion products is noted to be non-linear, adding complexity to the discussion.

Astrum
Messages
269
Reaction score
5
You have a butane torch and an oven.

Two scenarios:

1. Butane is burning in an oven heated to 200 C, does the burning point of the butane change at all?

2. Butane is burning in an oven heated to 2000 C, does the butane have a cooling effect on the oven?

The burning point of butane is 1950 C in air.

In the first situation, the ambient temperature is sure to increase, and I assume that the burning temperature of the butane will increase, simply because the surrounding air will not have as much of an effect on the butane.

In the second scenario, I haven't the slightest clue.
 
Science news on Phys.org
Astrum said:
You have a butane torch and an oven.

Two scenarios:

1. Butane is burning in an oven heated to 200 C, does the burning point of the butane change at all?

2. Butane is burning in an oven heated to 2000 C, does the butane have a cooling effect on the oven?

The burning point of butane is 1950 C in air.

In the first situation, the ambient temperature is sure to increase, and I assume that the burning temperature of the butane will increase, simply because the surrounding air will not have as much of an effect on the butane.

In the second scenario, I haven't the slightest clue.


Shouldn't this depend on what temp. the butane came in at?

Whether the heat of combustion at 2000 C is less or more than the heat capacity of the gas?
 
Burning the butane is exothermic and will never have a cooling effect. It will simply make the oven hotter. The burning temperature given is only valid for standard atmospheric conditions. http://en.wikipedia.org/wiki/Gas_burner

I suppose burning in a hotter environment will make the flame hotter.
 
Khashishi said:
Burning the butane is exothermic and will never have a cooling effect. It will simply make the oven hotter. The burning temperature given is only valid for standard atmospheric conditions. http://en.wikipedia.org/wiki/Gas_burner

I suppose burning in a hotter environment will make the flame hotter.

Aren't you neglecting the cooling effect of specific heat? Cold butane into a hot oven cools.

Is the exothermicity large enough to compensate?
 
rollingstein said:
Aren't you neglecting the cooling effect of specific heat? Cold butane into a hot oven cools.

Is the exothermicity large enough to compensate?

The combustion energy is 2.89 MJ/mol.

specific heat of Butane is 98.5 J/(K mol), so heating it by 1725 K takes 0.170 MJ/mol.
 
willem2 said:
The combustion energy is 2.89 MJ/mol.

specific heat of Butane is 98.5 J/(K mol), so heating it by 1725 K takes 0.170 MJ/mol.

Thanks! Clearly, no cooling effect.
 
The process is reactants ==> burning == products.
As stated the the adiabatic flame temperature and heat of combustion cna be stated for a standard atmosphere.
If the environment temperature increases, not all of the products will be formed ie perhaps CO instead of C02 will continue to be one of the species if the oven temperature is great enough. This will affect the flame temperature and and how much heat can be obtained from the reaction. It is not a linear relationship with temperature.
A certain oven temperature can be reached where the reactants will break apart into their constituent parts and no products are formed but continue to persist as a plasma.
 

Similar threads

Replies
24
Views
5K
  • · Replies 10 ·
Replies
10
Views
3K
Replies
9
Views
9K
  • · Replies 15 ·
Replies
15
Views
4K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 12 ·
Replies
12
Views
5K
  • · Replies 2 ·
Replies
2
Views
3K