Flash Point Autoignition Temperature Kindling Hydrocarbons Alkane Alkene

Overview

Engineering reference data for Flash Point Autoignition Temperature Kindling Hydrocarbons Alkane Alkene in thermodynamics.

Key Formulas

First Law

$\Delta U = Q - W$

Energy is conserved — heat added minus work done.

Ideal Gas Law

$PV = nRT$

Relates pressure, volume, and temperature of an ideal gas.

Heat Transfer

$Q = mc\Delta T$

Sensible heat transfer.

Carnot Efficiency

$\eta = 1 - T_C/T_H$

Maximum efficiency between two temperatures.

Variables

Symbol	Description	Unit
$U$	Internal energy	J
$Q$	Heat	J
$W$	Work	J
$P$	Pressure	Pa
$V$	Volume	m³
$T$	Temperature	K

Hydrocarbons - Autoignition Temperatures and Flash Points Data

Key Relationships and Safety Considerations

• Flash Point vs. Fire Point: Flash point is the minimum temperature at which vapors ignite momentarily upon applying an external flame. Fire point is the slightly higher temperature at which vapors sustain continuous combustion for at least 5 seconds after ignition.

• Pressure Effect: Autoignition temperature (AIT) generally decreases as system pressure increases. This is critical for safety when compressing hydrocarbon gases, as the risk of spontaneous ignition rises.

• Volatile Compounds: Hydrocarbons with high vapor pressures (lighter, lower molecular weight) typically have low flash points, making them highly flammable at ambient or near-ambient temperatures.

• Boiling Point Correlation: There is a general trend where flash point increases with increasing boiling point for similar hydrocarbon classes.

• Hazardous Area Classification: Equipment temperature ratings in hazardous environments (e.g., ATEX, NEC) are directly determined by the AIT of the surrounding flammable substances. The maximum surface temperature of equipment must be safely below the AIT.

Interactive Charts

References

• Original Source