Propane Butane Mix
Reference data and engineering information about propane butane mix for combustion applications.
propanebutanemix
Overview
Engineering reference data for Propane Butane Mix in combustion engineering.
Key Formulas
Heat Release
Fuel energy release rate.
Air-Fuel Ratio
Mass of air per mass of fuel.
Excess Air
From flue gas oxygen measurement.
Variables
| Symbol | Description | Unit |
|---|---|---|
| Heat release rate | W | |
| Mass flow rate | kg/s | |
| Heating value | J/kg | |
| Air-fuel ratio | — |
Vapor Pressure Data
The following table shows the gauge pressure (psig) of propane-butane liquid mixtures at various temperatures and composition ratios.
16 rows
Temperature(°F) | 100% Propane(psig) | 70% Propane / 30% Butane(psig) | 50% Propane / 50% Butane(psig) | 30% Propane / 70% Butane(psig) | 100% Butane(psig) |
|---|---|---|---|---|---|
| -44 | 0 | 0 | 0 | 0 | 0 |
| -30 | 6.8 | 0 | 0 | 0 | 0 |
| -20 | 11.5 | 4.7 | 0 | 0 | 0 |
| -10 | 17.5 | 9 | 3.5 | 0 | 0 |
| 0 | 24.5 | 15 | 7.6 | 2.3 | 0 |
| 10 | 34 | 20.5 | 12.3 | 5.9 | 0 |
| 20 | 42 | 28 | 17.8 | 10.2 | 0 |
| 30 | 53 | 36.5 | 24.5 | 15.4 | 0 |
| 40 | 65 | 46 | 32.4 | 21.5 | 3.1 |
| 50 | 78 | 56 | 41 | 28.5 | 6.9 |
| 60 | 93 | 68 | 50 | 36.5 | 11.5 |
| 70 | 110 | 82 | 61 | 45 | 17 |
| 80 | 128 | 96 | 74 | 54 | 23 |
| 90 | 150 | 114 | 88 | 66 | 30 |
| 100 | 177 | 134 | 104 | 79 | 38 |
| 110 | 204 | 158 | 122 | 93 | 47 |
Source: engineeringtoolbox.com
The following table provides the absolute vapor pressure of pure butane.
9 rows
Temperature(°C) | Vapor Pressure (abs)(bar) |
|---|---|
| -101.5 | 0.0013 |
| -77.8 | 0.013 |
| -59.1 | 0.053 |
| -44.2 | 0.13 |
| -16.3 | 0.53 |
| -0.5 | 1.01 |
| 18.8 | 2.03 |
| 50 | 5.07 |
| 79.5 | 10.1 |
Source: engineeringtoolbox.com
Component Properties & Design Considerations
- Propane (C₃H₈): More suited to colder environments due to its lower boiling point (-44°F / -42°C).
- Butane (C₄H₁₀): Has a higher boiling point (33°F / 0.6°C), making it more volatile in warmer conditions.
- Evaporation Requirements: Evaporation is not solely dependent on temperature; it requires heat input. Limited heat transfer causes the liquid to cool, reducing the evaporation rate.
- System Design:
- Large Consumers: May require external heat exchangers using hot water, electric heaters, or combustion of the LPG itself to supply the necessary evaporation heat.
- Small Consumers: Rely on heat transfer from the surroundings. Container material is critical: composite containers offer less heat transfer than steel containers and can cause performance issues at lower ambient temperatures.