Barometers, Natural Gas, and LPG: Properties and Uses
What is a Barometer, How Does it Work, and What is its Origin?
The barometer, invented by Evangelista Torricelli, measures the force per unit area exerted by the weight of the atmosphere, known as atmospheric pressure. Torricelli’s barometer used a mercury-filled tube approximately 76 inches high, balanced by atmospheric pressure. His studies indicated that air exerts a pressure of 1,033 grams per square centimeter (1.033 g/cm2).
What are the Differences Between Mercury and Aneroid Barometers?
A mercury barometer measures atmospheric pressure by balancing it against the weight of a mercury column. Units are typically millimeters of mercury (mm Hg) or hectopascals (hPa). It consists of a glass tube about 850 mm high, sealed at the top and open at the bottom. When filled with mercury and placed open-end down in a mercury-filled container, the mercury level in the tube drops to about 760 mm above the container’s level, creating a near-perfect vacuum at the top. Changes in atmospheric pressure cause the mercury level to fluctuate slightly. A mercury barometer can be accurate to within 0.1 mm.
An aneroid barometer, on the other hand, is more convenient. It measures atmospheric pressure by the deformation of an elastic wall in a partially evacuated cylinder, which moves a needle. Aneroid barometers are particularly useful because pressure decreases rapidly with increasing altitude.
What are Natural Gas and Liquefied Petroleum Gas?
Natural gas is a nonrenewable energy source consisting of a mixture of light gases. It is often found in oil fields, either dissolved in oil or associated with oil or coal deposits. Natural gas is extracted directly from the earth and transported through pipelines to homes and consumption centers. Being lighter than air, it can be easily ventilated in case of leaks by opening doors and windows.
Liquefied petroleum gas (LPG) is a mixture of condensable gases present in natural gas or dissolved in oil. While gaseous at ambient temperature and pressure, LPG components are easily condensed, hence the name. Primarily composed of propane or butane/propane mixtures, LPG is man-made, heavier than air, and stored in liquid form in cylinders or underground tanks. It is commonly used in homes with gas cylinders.
How is Natural Gas Obtained and What are its Characteristics?
Natural gas can be obtained in several ways. It is commonly found in oil fields, dissolved or associated with oil or coal deposits. It can also be produced through the decomposition of organic waste (garbage, plants – marsh gas) in treatment plants (urban wastewater treatment, olive mill waste processing plants, etc.). The gas obtained through this process is called biogas. Once obtained, natural gas is cooled to its liquefaction temperature, stored, and maintained in a liquid state through cryogenic cooling.
Natural gas typically contains 88-94% methane (CH4). Other components are separated as they lack energy capacity. Methane, the main component, is odorless and colorless, so mercaptan is added for detection. The risk of fire from natural gas is generally lower than that of gasoline and diesel. Its flame is 60% visible.
Characteristics of LPG
LPG, commonly known as cooking gas, is a hydrocarbon mixture of butane and propane, obtained from refining crude oil or extraction from wells. Similar to gasoline, it has an octane rating of 115. LPG is less toxic, significantly reducing carbon monoxide and sulfur dioxide emissions. It contains no chemical additives like lead and aromatics, contributing to reduced pollution and improved health and environmental conditions.
Uses of Greenhouse Gases
LPG is primarily used as a domestic fuel for cooking and water heating.
Natural gas has numerous applications in industry, commerce, power generation, the residential sector, and passenger transport. Some examples include:
- Industrial processes
- Commercial heating
- Electricity generation
- Residential heating and cooking
- Vehicle fuel
Additionally, natural gas serves as a feedstock in various chemical and industrial processes. It can be relatively easily and economically converted into hydrogen, ethylene, or methanol, which are basic materials for various plastics and fertilizers.
Safety Considerations
LPG
- In case of a gas leak, isolate the area.
- Avoid smoking, flames, sparks, and static charges.
- Avoid contact and inhalation of the gas.
- If clothes get wet with gas, remove them quickly to prevent irritation and risk of ignition.
Natural Gas (NG)
- In case of a leak, avoid open flames or sparks.
- Do not operate light switches.
- Close gas valves.
- Ventilate contaminated areas.
- Do not manipulate, modify, or alter internal natural gas installations.
General (GL)
- If you smell gas, shut off the main gas supply and ventilate the area. If the smell persists, evacuate.
- Keep hazardous substances like kerosene, paraffin, alcohol, floor wax, paint, etc., at least 1 meter away from gas installations.
- When starting a gas appliance, turn the gas cock to the open position, light the match first, and then operate the gas knob.
- Never use plastic hoses to connect appliances to the gas network.
- If a flame goes out, turn off the gas flow at the appliance knob for a few minutes and ventilate before relighting.
- Smoking is prohibited near gas installations.
- Avoid dropping gas cylinders.
- Ensure areas of use and storage are well-ventilated.