Essay Code C15
Propane, the Liquefied Petroleum Gas (well written, but you don’t have a picture of the molecule)
It’s a blazing summer day. The weather calls for an iced glass of lemonade and a backyard barbeque. You turn the knob on your gas grill and vibrant flames emerge from underneath the grill racks. This is thanks to the propane in the gas cylinder tank which supplies the fuel for the burning to continue.
Propane is not just used for heating grills; it has numerous uses evident throughout the household. It’s easy to take propane for granted because one does not often consider the subtle mechanics of everyday life. In fact, propane “supplies about 4 percent of our total energy needs.”[2] Its least obvious use lies in water heating systems in the everyday home. Typically, a tank of water is preheated using propane. Once the water is needed, heated water flows out of the faucet, allowing for comfortable warm baths and hot loads of the washing machine. More evidently, propane is involved in the use of everyday appliances such as the stove. Similarly to the barbeque grill, the stove is powered by propane, allowing for one to cook meals at home.
Outside of the home, propane is used to power vehicles. On land, propane is used to power cars and farming equipment. It has the title of being an alternative fuel source according to the 1990 Clean Air Act which fuels the debate over whether propane should replace gasoline.[4][5] In the sky, hot air balloons are equipped with lightweight propane tanks. Ignited propane vapors burn and heat the surrounding air molecules under the upper parachute.[3] (can you go further on why propane is not used in cars, or at least not all cars on the road.)
The energy that is released from propane comes from the chemical process known as combustion reaction. A compound, such as propane, is burned in oxygen producing carbon dioxide, water, and heat:
Propane + Oxygen --> Carbon Dioxide + Water + Heat
C3H8 + 5 O2 --> 3 CO2 + 4 H2O + Heat
The heat is observed in the form of fire, which one can see when one lights the stove or turns the knob on an outdoor gas grill. Many hydrocarbons exhibit this property, and similarly to propane, will react via a combustion reaction.
Dangers of Propane
Despite all the benefits the existence of propane offers, propane does have its consequences if not handled properly. A prime example of the dangers of propane is what is now known as the Sunrise Propane Incident which occurred in Toronto, Ontario, Canada. Sunrise Propane was a facility that house and sold propane. Workers regularly transported to and from the facility. However, the company illegally used a method of transport called truck-to-truck transfers which increase the risk of fires and leaks.
On August 10, 2008, there was a hose leak as a result of truck-to-truck transfers. Propane vapors escaped from the sealed containers of propane. All it took was a spark to ignite the vapors that leaked and cause a devastating explosion. The blast resulted in irreversible damage: one employee and one fireman were killed, while “12,500 residents”[1] were forced to evacuate from their homes. Windows were shattered as debris from the explosion dispersed.
After investigations, it was concluded that the entire incident was indeed preventable. The company should not have been using the method of truck-to-truck transfers to transport propane. Sunrise Propane failed to properly maintain a safe working environment and adequate safety training to handle propane. From this incident, it is clear that regulations for propane use must be proposed and enforced in order to prevent injury.
Safety Measures
Fortunately, today there are many safety measures and regulations in place that prevent catastrophes like the Sunrise Propane Incident from happening again. The National Propane Gas Association (NPGA) developed a training program to educate service workers in handling propane. It is called the Certified Employee Training Program (CETP) and covers the basics to technical details on appliance installation.[2] The Propane Education and Research Council (PERC) also distributes brochures and materials for the education of propane consumers. The aim is to teach safe propane practices and prevent injuries.
Safety measures are in place for those that are not knowledgeable of proper propane handing. The most significant feature in propane safety is the addition of an odorant that signals the presence of propane in the situation of a leak. Propane independently is odorless and difficult to detect without outside aide. Additionally, all propane tanks are required to be fitted with pressure relief valves.[2] These valves automatically open when there is an excess pressure buildup inside the chamber of the tank due to external circumstances such as high temperatures. High temperatures create an increase in the movement of molecules, which results in increased pressure. There are also line valves and remote shutoff systems, which allow one to manually, close the flow of propane if a leak is detected.
Propane Production
Propane undergoes tedious processing before its capable of wild explosions and worthy of developing safe use practices for. Dr. Walter O. Snelling is credited with the discovery of a method to extract propane and the birth of the propane industry. Snelling made it seem so obvious with his ingenuity. He was presented the mystery of disappearing gasoline. A car owner complained that the amount of gas he purchased would always decrease at a significant rate. Snelling figured out that the gas vapors were indeed evaporating from the container through the lid.[4] The cork would pop off as vapors formed within the container and would release the gas, explaining the significant drop in volume of the gas.[8] He then proposed a technique for fractional distillation of the gas into its separate components, one of which is propane. The distillation relies on the nature of the gases having varying boiling points. Gases with lower boiling points would vaporize quicker than those gases with higher boiling points. Snelling isolated propane and discovered its tremendous usefulness.
But propane doesn't start with Snelling. Propane initially starts out as a component in a mixture of naturally occurring gas deposits which were formed over millions of years. Before it can be used in the household, propane must be isolated from the rest of the deposit through natural gas processing or produced as a byproduct of oil refining.[6] Natural gas processing involves many steps before the desired product is obtained. First, the oil is removed from the gas using a gas-oil separator. The gas proceeds to a second chamber, the condensate separator, in which water is removed. Leftover water residue is dehydrated in the third chamber. Contaminants, such as hydrogen sulfide, carbon dioxide, helium, and oxygen, are then separated, followed by nitrogen extraction. Finally, methane and other natural gas liquids are isolated from propane.[7] Snelling would have been impressed with the new complexity of his original process.
Figure 4. Steps in natural gas processing. [12]
Once the propane is pipeline quality, it is ready to be transported from refining facilities to one's home in the form of liquid. A vast network of underground pipelines has been developed to transport propane. Propane travels through the pipes towards distribution terminals, which act exactly as one would guess. The role of "distribution terminals" is to distribute the propane to "bulk plants" which temporarily house the propane before it is shipped off in trucks and other vehicles. [6] Propane dealers are supplied with propane by these bulk plants, and consumers are supplied with propane by these propane dealers. Propane is sold in small cylindrical tanks, or can be filled directly into one's home propane tank, located either outside or underground. As long as the tank is filled, one can continue to experience the privilege of having propane at home. From the mere gas deposit to a necessity that powers the majority of homes today, propane is truly a spectacular gas.
(more needs to be written)
References
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[6] http://lsa.colorado.edu/essence/texts/propane.html
[7] http://www.eia.gov/pub/oil_gas/natural_gas/feature_articles/2006/ngprocess/ngprocess.pdf
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[12] http://www.eia.gov/pub/oil_gas/natural_gas/feature_articles/2006/ngprocess/ngprocess.pdf