Propane is a common fuel used in numerous industries, including manufacturing, agriculture, and transportation. In industries such as gas energy, chemical synthesis, and cold chain transportation, propane is both an efficient and clean energy source and a key chemical feedstock. Accurate flow measurement is crucial for production safety and process optimization.
The post helps you make an informed choice of a propane flow meter based on your needs.
What is Propane?
Propane is a component of natural gas and petroleum. It is primarily produced through natural gas liquefaction or petroleum cracking. It has a low boiling point (-42.1°C) and a high calorific value. So, propane can also be liquefied. So it is easier to store and transport.
Propane is also an important clean energy source, with its primary combustion products being carbon dioxide and water. Compared to traditional fuels, it produces fewer pollutants.
Propane’s primary applications include the petrochemical industry, environmental protection, and scientific research. Propane is usually used as a refrigerant, internal combustion engine fuel and raw material for organic synthesis. It can also be used as a cracking feedstock to produce ethylene, propylene, acrylonitrile, nitropropane, and tetrachloroethylene. In refineries, propane is also used as a solvent for deasphalting and desulfurization, as well as a coolant for other petrochemical products.
Read More about: Industrial Propane Flow Meters for Liquid/Gas Propane Measurement
Physical and chemical properties of propane
| Density | 0.564 |
| Boiling Point | -43 ºC |
| Melting Point | -188 °C(lit.) |
| Molecular Formula | C3H8 |
| Molecular Weight | 44.0956 |
| Flash Point | -98 ºC |
| Exact Mass | 44.0626 |
| LogP | 1.4163 |
| Appearance | Colorless, odorless gas |
| Vapor Density | 1.5 (vs air) |
| Vapor Pressure | 190 psi ( 37.7 °C) |
| Storage conditions | Storage Precautions: Store in a cool, ventilated warehouse dedicated to flammable gases. Keep away from fire and heat sources. The storage temperature should not exceed 30°C. Store separately from oxidants and halogens and avoid mixing. Use explosion-proof lighting and ventilation. Do not use spark-generating machinery and tools. Emergency leak response equipment should be available in the storage area. |
| stability | 1. Stability: Stable |
| 2. Incompatible Materials: Strong oxidants, strong acids, strong bases, halogens | |
| 3. Polymerization Hazard: No polymerization | |
| Molecular structure | 1. Molar refractive index: 15.94 |
| 2. Molar volume (cm³/mol): 78.0 | |
| 3. Isotonic volume (90.2K): 151.5 | |
| 4. Surface tension (dyne/cm): 14.1 | |
| 5. Dielectric constant: 1.67 | |
| 6. Dipole moment (10-24 cm³): Not available | |
| 7. Polarizability: 6.32 | |
| Computational Chemistry | 1. Hydrophobicity parameter calculation reference value (XlogP): 1.8 |
| 2. Number of hydrogen bond donors: 0 | |
| 3. Number of hydrogen bond acceptors: 0 | |
| 4. Number of rotatable chemical bonds: 0 | |
| 5. Number of tautomers: None | |
| 6. Topological molecular polar surface area: 0 | |
| 7. Number of heavy atoms: 3 | |
| 8. Surface charge: 0 | |
| 9. Complexity: 0 | |
| 10. Number of isotopic atoms: 0 | |
| 11. Number of determined atomic stereocenters: 0 | |
| 12. Number of uncertain atomic stereocenters: 0 | |
| 13. Number of determined chemical bond stereocenters: 0 | |
| 14. Number of uncertain chemical bond stereocenters: 0 | |
| 15. Number of covalent bond units: 1 | |
| More | 1. Properties: Colorless liquefied gas, odorless in pure form. |
| 2. Melting point (℃): -189.7 | |
| 3. Boiling point (℃): -42.1 | |
| 4. Relative density (water = 1): 0.58 (-44.5°C) | |
| 5.Relative vapor density (air = 1): 1.6 | |
| 6. Saturated vapor pressure (kPa): 840 (20°C) | |
| 7. Heat of combustion (kJ/mol): -2217.8 | |
| 8. Critical temperature (℃): 96.8 | |
| 9. Critical pressure (MPa): 4.25 | |
| 10. Octanol/water partition coefficient: 2.36 | |
| 11. Flash point (℃): -104 | |
| 12. Ignition temperature (℃): 450 | |
| 13. Upper explosion limit (%): 9.5 | |
| 14. Lower explosion limit (%): 2.1 | |
| 15. Solubility: Slightly soluble in water, soluble in ethanol and ether. | |
| 16. Relative density (20℃, 4℃): 0.50039s | |
| 17. Relative density (25℃, 4℃): 0.4927s | |
| 18. Refractive index at room temperature (n20): 1.2862s | |
| 19. Refractive index at room temperature (n25): 1.2814s | |
| 20. Lennard-Jones parameter (K): 287.89 | |
| 21. Lennard-Jones parameter (A): 4.8912 | |
| 22. Solubility parameter (J·cm-3) 0.5: 13.091 | |
| 23. Critical density (g·cm-3): 0.220 | |
| 24. Critical volume (cm3·mol-1): 200 | |
| 25. Critical compression factor: 0.277 | |
| 26. Eccentricity factor: 0.152 | |
| 27. van der Waals area (cm2·mol-1): 5.590×109 | |
| 28. van der Waals volume (cm3·mol-1): 37.570 | |
| 29. Gas phase standard heat of combustion (enthalpy) (kJ·mol-1): -2219.15 | |
| 30. Gas phase standard claimed heat (enthalpy) (kJ·mol-1): -7104.68 | |
| 31. Gas phase standard entropy (J·mol-1·K-1): 270.31 | |
| 32. Gas phase standard formation free energy (kJ·mol-1): -24.3 | |
| 33. Gas phase standard hot melt (J·mol-1·K-1): 73.60 |
Gas Propane vs. Liquid Propane
Propane has a boiling point of approximately -42.1°C. When it is below this temperature or pressure is applied, it changes from a gas to a liquid. The liquefaction process is typically carried out in storage tanks or transport containers to increase its energy density. Direct contact with liquid propane can also cause frostbite.
Gaseous propane is denser than air and, if leaked, will settle in low-lying areas on the ground.
Liquid propane has a density of approximately 0.5 g/cm³ and a much smaller volume than gaseous propane. This makes liquid propane easier to store and transport.
Gaseous propane is highly diffusive and poses a higher fire risk. Leaked liquid propane vaporizes rapidly, which causes a sudden increase in localized concentration. This increased concentration can cause an explosion or fire.
Challenges of Propane Flow Measurement:
When exposed to open flames or high temperatures, propane can cause fire and explode. Propane is insoluble in water. But it can form explosive mixtures when in contact with air.
So, when using a propane flow meter, appropriate safety measures must be taken can ensure the safety of industrial processes. Common safety measures include using explosion-proof flow meters and reasonable ventilation.
Propane is a colorless, slightly odorous component of liquefied petroleum gas. Several of its characteristics influence the selection of a propane flow meter.
Flammability and Explosiveness:
The explosive limits of propane range from 2.1% to 9.5%. Propane is highly explosive when exposed to open flames, high temperatures, or sparks. Due to propane’s high calorific value and explosive potential, we should consider stricter requirements for the flow meter’s explosion-proof performance.
Liquefaction:
Propane has a key temperature of 96.67°C and a key pressure of 4.25 MPa. At a normal temperature, when the pressure reaches 0.8–1.5 MPa, propane will liquefy.
In the industry, propane is usually transported in liquid or gaseous form. And its state is susceptible to temperature and pressure fluctuations. So, it is vital to select a flow meter that can withstand the temperature and pressure conditions encountered by propane. Some flow meters have temperature and pressure compensation, which can provide more accurate measurement data.
Density:
Under standard conditions (0°C, 101.325 kPa), the density of gaseous propane is approximately 2.01 kg/m³, heavier than air (approximately 1.293 kg/m³). Leaks often accumulate in low-lying areas and are difficult to disperse, posing a serious safety hazard. Therefore, it is crucial to properly address propane measurement issues during measurement.
Chemical Stability and Corrosiveness:
Propane is chemically stable at room temperature. But liquid propane can dissolve plastics and rubber. So, propane flow meters need to use some appropriate seals. If propane contains trace impurities, such as hydrogen sulfide, it may corrode metals such as copper and zinc.
Propane Flow Meter Types
A propane flow meter is a propane flow meter used to measure the flow of propane in a pipeline. The following are common propane flow meter types.
Propane Gas Flow Meter
Vortex Flow meter:
Vortex flow meters can be used to measure the flow of most gases, including propane, propylene, oxygen, air, and hydrogen. Vortex flow meters are commonly used to measure liquid and gas flow.
Read More about: Industrial Steam Vortex Flow Meters-Multivariate Measurement
Orifice Flow meter:
An orifice flow meter is a high-turndown differential pressure flow meter that combines a standard orifice plate with a differential pressure transmitter. It can measure the flow of gases, steam, liquids, and natural gas. It is usually used for process control and measurement of propane in the petroleum, chemical, metallurgical, power, heating, and water supply industries.
Orifice flow meters are usually used in various fields, including coal, chemical, transportation, construction, textile, food, medicine, agriculture, environmental protection, and daily life.
Read More about: Differential Pressure Flow Meter Technical Guide
V-Cone Flow meter:
A V-Cone Flow meter is a differential pressure flow meter. Due to the characteristics of propane, it can be used for measurement. It measures flow rate by utilizing the pressure differential generated when a fluid passes through a specially shaped conical pipe. For propane gas, V-cone flow meters have many advantages:
- High accuracy
- Durability
- Wide applicability
- Low maintenance
Read More about: V-Cone Flow Meter VS. Venturi Flow Meter
Liquid propane flow meter
Coriolis mass flow meter
A Coriolis flow meter can also measure the flow rate of liquid propane. It is the most accurate type of flow meter. In the energy industry, they are used for metering and controlling energy sources. A Coriolis mass flow meter usually consists of a sensor and a transmitter. The flow meter includes two parallel flow tubes, a drive coil, and a detection coil. The transmitter provides the excitation voltage, receives and processes the signal from the detection coil, and finally outputs the mass flow rate.
Read More about: Turbine Flow Meter and Coriolis Mass Flow Meter-Difference and Selection
Turbine flow meter
Liquid turbine flow meters can measure the flow rate of liquid propane under high-pressure or low-temperature conditions. As fluid flows through the meter, it impacts the precision-designed turbine rotor within, driving it to rotate. The rotor’s speed is proportional to the propane’s average flow rate (i.e., volumetric flow rate). A capacitive sensor converts the turbine’s mechanical speed into an electrical pulse signal of the corresponding frequency. By detecting the pulse frequency, the instantaneous and cumulative flow rates can be accurately calculated.
Read More about: An Overview of Turbine Flow Meters
Sino-Inst Featured Propane Flow Meter
Propane Flow Meter Applications
Propane gas flow meters are used in various fields. There is a detailed introduction.
- Natural Gas Production and Transportation: Propane, as the primary component of natural gas, is used to measure its production, transportation, and distribution.
- Industrial Process Control: In some industrial fields, propane flow meters are usually used to monitor and control gas flow.
- Environmental Monitoring: In environmental protection, propane flow meters can be used to monitor propane emissions from emission sources. It can help to reduce greenhouse gas emissions.
- Gas Supply: A Propane flow meter is used to monitor propane supply for domestic, commercial, and industrial use.
- Laboratory Research: In laboratory experiments, propane flow meters are used to measure propane flow during experiments. In some universities, research institutions, and R&D centers of listed companies have chosen Sino-Inst flow meters for their accurate experiments.
- Energy Management: In energy management, propane flow meters are used to monitor energy consumption. It can optimize energy use.
Understand the Importance of Choosing the Right Propane Flow Meter
The fundamental function of a flow meter is to provide accurate flow measurement. Choosing the wrong flow meter can lead to measurement errors, compromising efficiency and safety.
Wrong flow meters are often made of inferior materials and are prone to failure in extreme temperatures, pressures, or corrosive environments. Such failures not only cause downtime but also damage equipment, increasing maintenance costs.
Poor-quality flow meters often require frequent maintenance and calibration, increasing operating costs. High-quality flow meters, on the other hand, are generally designed to be more durable and require less maintenance, saving significant time and money in the long run.
Particularly in industries with flammable and explosive materials like propane, flow meter failure can pose a safety hazard. A malfunctioning flow meter could lead to propane leaks or explosions. So, selecting a high-quality flow meter is necessary to ensure operational safety.
Every industry has strict regulations and standards requiring flow meters that meet specific accuracy and performance standards. Using inferior flow meters can lead to non-compliance, which results in fines or legal liability.
Flow meters provide accurate data for data-driven decision-making. Inaccurate data can lead to wrong decisions and cause production inefficiencies and endanger industrial safety.
How to Choose the Right Propane Flow Meter?
There are some specific considerations.
- Flow Range: The flow meter’s range should be larger than the actual operating flow range.
- Pressure: The flow meter must withstand a pressure range, and when using the flow meter, the operating pressure must be controlled within the appropriate range.
- Diameter (DN): Select the appropriate flow meter model based on the pipe size. A diameter that is too large or too small will not properly connect to the measuring pipe and may even cause leakage and explosion.
- Connecting Method: Choose a flange connection, threaded connection, or other connection method based on site conditions.
- Temperature Range: Consider the actual operating temperature range of the propane flow meter. The temperature range that the flow meter can withstand should be greater than the temperature of its actual working conditions. Since propane is easy to liquefy, in actual operation, we need to control the propane tank in a reasonable temperature range.
- Output Signal: Select the right pulse or current signal based on real system requirements.
- Media compatibility: We should ensure the flow meter is compatible with propane.
What PSI does propane turn to liquid?
The liquefaction pressure of propane depends on temperature. The liquefaction pressure varies at different temperatures. It is approximately 123 psi at 20°C and 36 psi at -20°C.
At its key temperature of 96.8°C, it requires approximately 616 psi to liquefy.
In practice, propane typically liquefies at a pressure of 72-87 psi (0.5-0.6 MPa) for easier storage and transportation.
Why is gas not flowing from my propane tank?
The gas valve is not open. Every propane tank always has a gas valve. If this valve is not open, gas cannot flow from the tank smoothly. Please check the valve to confirm that it is open.
The connection Issue is wrong. The propane tank cap is not properly connected, which prevents gas from being released from the tank. So, Check the connection to ensure they are tight and leak-tight.
Pressure is abnormal. After filling the propane tank, the gas may not be released properly due to low pressure. So, we should check the gas pressure. The aim is to meet the required standards and adjust it if necessary.
How to Tell If a Propane Tank is Overfilled?
We provide two ways to determine if a propane tank is overfilled.
Weigh the tank. Then, place your propane tank on a scale and write down its current weight. Subtract the weight of the empty tank from the actual weight. Since 1 gallon (3.8 liters) of propane weighs approximately 4.2 pounds, simply divide the remaining weight by 4.2 to determine how much propane you have left.
Install a pressure gauge on the tank. A pressure gauge is a small dial that screws onto the propane tank. It measures the pressure inside the tank to determine how full it is. Close the propane tank's supply valve and remove the gas line. Thread one end of the pressure gauge onto the tank and connect the gas line to the other end. Open the gas supply valve on the gas tank and check the pressure gauge.
All in all, measuring propane flow is a dangerous process. Choosing the right flow meter is necessary to ensure safety. If you are confused about flow meter selection, please feel free to contact us. We are professional flow measurement engineers and can serve as your technical advisor free of charge.
