Uses of Crude Petroleum

Crude petroleum has been known for thousands of years. The American Indians used the black sticky substance for war paint and as an insulation material. However, it wasn't until the 1870's that crude petroleum found other uses as a source of fuel. Chemically speaking, crude petroleum is a highly complex mixture of compounds chemically composed of Hydrogen and Carbon called Hydrocarbons. As a fuel it is useless until it has been processed. The initial processing consists of distilling fractions of petroleum. Each fraction contains a simpler mixture of Hydrocarbons. The lower boiling fraction contains four or less carbons and is called natural gases. They are called natural because they exist in large deposits in underground spaces. Other fractions of crude petroleum include a Kerosene, gasoline, light oil, heavy oil, and diesel all of which are liquids at room temperature because of their molecular size. The solid residues are highly complex waxes and tar like products. Once the initial fractional distillation is complete, each of these fractions need to be further purified by using special chemical processes known as "cracking" and polymerization.

Cracking processes chemically break more complex molecules into smaller molecules that will increase the yield of the liquid fractions that are the fractions most developed as fuels. Polymerization is a chemical process where smaller molecules in the natural gas fractions are combined to form more complex molecules of the liquid variety. Some of these processes involve special chemical compounds called catalysts. In addition to improving the yield of fuels, these fractions are further refined by adding special additives that improve the burning efficiency of the fuel. One of the earlier additives that were added to the gasoline fraction to improve the burning efficiency (octane rating) was Tetraethyl lead. It was referred to as "leaded gasoline". However, it soon became obvious that the additive was undergoing chemical decomposition at the high heats of the combustion process within the internal combustion engines that consumed the fuel. The decomposition products contained vaporous lead that could be inhaled. This would result in the accumulation of lead in the body leading to serious destruction of the nervous system.

There is a theory in ancient history that suggest that the Roman Empire crumbled partly because the Caesars, Senators, and other decision makers of the Roman Empire consumed lead from the lead contained in the ceramic clay drinking cups that they used. The acid nature of the wine dissolved or leached the lead from the clay vessels and accumulated in their bodies. Improperly glazed pottery can allow lead from the clay to be leached by acid foods such as vinegar. Any pottery that might be used as cooking or serving utensils could be a potential source of lead poisoning. The governments have also removed the lead found in paints because children were known to chew on flaked paint specks containing high concentrations of lead. In the 1970's the United States began an effort to phase out "leaded" gas and replace the lead additive with other additives that do not decompose into harmful pollutants. In addition, Congress passed a law that required special anti-pollution devices called "catalytic converters" installed in the exhaust system of cars and trucks that effectively removed Nitrogen Oxides produced when Nitrogen which is 80% of the atmosphere combines with the Oxygen (19%) to produce harmful Nitrous Oxides in the combustion chambers of engines. These oxides of Nitrogen are very dense and can cause respiratory problems. In addition, the Oxides can chemically react with other components in the atmosphere with the aid of energy from radiation of the sun to produce further harmful pollutants. These are basically photochemical reactions that are reactions involving radiation as an energy source for the chemistry to occur. The pollutants produced have been referred to as "photochemical smog".

It has also been suggested that some of these components can be destructive of the Ozone layer in the Ionosphere. The catalytic converters use Platinum as a catalyst that can decompose the Nitrous Oxides into Nitrogen and Oxygen. Further laws have been passed that require all catalytic converters to undergo exhaust emission tests to check for the presence of Nitrogen containing oxides. Other pollutants include Carbon Monoxide and Carbon Dioxide which can accumulate to dangerously high levels in congested areas. Some other hazards of petroleum have been the danger of oil spills from leaking pipelines and tanker ship ruptures due to collision. There have been a number of oil slick disasters where tankers ran aground due to faulty navigation or collided with other ships. These oil slicks can be a source of pollution where aquatic and bird life can be damaged. Fish depend upon oxygen from the water; aquatic plants depend upon the sun's rays for photosynthetic production of Oxygen. When the crude petroleum covers the water surface, this deprives the ocean of sun light. In addition oil will collect on the wings of bird life which prevents them from flying. The birds have to be cleaned with a detergent substance to remove the oil from their feathers. The containment of the oil slick is very difficult. Wind conditions can quickly spread or move a slick making it almost impossible to contain. Special skimmers have to be used once the oil slick has been cornered.

Recently, special cultured microbes have been used that digest the oil and allow the slick to be broken up into smaller more manageable slicks. Once the slicks have been reduced in size other detergent containing agents can further break down the slick. Eventually, the oil must be removed by physical skimming. In the future these special microbes might be used to totally consume oil slicks. Another danger is the burning of an oil rig. A number of off shore oil rigs have caught on fire. These fires are extremely difficult to put out. There are very few fire fighting teams that are prepared to fight such a fire. The burning of crude petroleum produces heavy plumes of black smoke that can block out the sun's rays with predictable results. In addition to using the petroleum as a fuel, petroleum is also a raw material for the polymer industry. It is sometimes called the petrochemical industry, and it involves the production of plastics, textiles, paints, and resinous materials. All of these synthetic materials are produced as a result of chemically polymerizing the refined components of crude petroleum. These complex polymers offer another environmental hazard since many of them are not decomposed by biological and chemical decomposition of the polymer. In other words, they are "non-biodegradable". Other polymers will produce harmful pollutants when they do decompose.

Our society will have to learn how to handle these polymeric products that have in many ways made our life more comfortable. The gasoline and diesel fractions have been the principal sources of fuel from the processing of crude petroleum. However, in an effort to conserve gasoline supplies, ethanol has been added to the gasoline. Ethanol that can be produced by the chemical fermentation of corn or wheat is a clean fuel and it improves the octane rating of the "Gasohol that has been more popular in South American countries. Recently it has been shown that internal combustion engines can be altered to burn natural gas, primarily propane. Propane is less expensive to process but the conversion process for the engine is extremely expensive. If gasoline continues to increase in cost, eventually the cost of engine conversion will be offset by the cost savings of using liquid propane. The propane is stored in a more convenient form as a liquid. Propane is also extremely clean burning and produces no pollutants provided catalytic converters are installed. The cost per gallon of liquid Propane is about 50% cheaper than gasoline.

A burning question remains unanswered that with all the pollution that crude petroleum products produce, why do countries rely so heavily on petroleum? The reason is the fact that crude petroleum is in liquid or suspended matter form. In that form it can easily be pumped to the surface using oil well rigs. Once the oil is out of the ground it can be easily and inexpensively be transported through pipelines. For example, the Alaskan North slope oil range transports the crude petroleum through one of the longest pipelines in the world extending over some of the earth's most rugged terrain.

Another gigantic potential source of petroleum can be found locked in the millions of tons of shale deposits that form the basis of the great Rocky Mountains. Hundreds of thousands of years ago the area of the Rocky Mountains was under water. As these waters receded, living matter was caught in the shale formations. The process of extracting the oil from the shale is very expensive and is not presently cost effective. In addition, once the shale has been extracted, the ecological balance must be maintained. Many doubt that it can be accomplished. It has been estimated that there is enough oil in the shale deposits of the mountain ranges of the Rocky and Allegany Mountains to supply oil needs for decades. Yet another potentially huge source of petroleum lies beneath the ocean's floor. Two-thirds of the earth's surface is covered water. Most of that land has not been drilled, but what few off shore drilling sights that have been drilled have yielded rich deposits. There is a great controversy concerning the use of off shore sites for drilling oil. Many environmentalists say that the environmental impact would be too severe if drilling was conducted off shore.

Quite often in the search for petroleum, large pockets of natural gas are found. In the past, these deposits have been burned off at the surface, but the natural gas offers a cheaper cleaner burning fuel. Natural gas is used in heaters as well as special converted engines. It is also easy to transport through pipelines. We will have to learn to harness the natural gas deposits that we have instead of wasting them. Besides being processed and used for fuel sources, petroleum can also be a source of a wide range of organic compounds that forms the basis of the petro-chemical industry. Hundreds of plastics, synthetic textile fibers, synthetic rubber products, pharmaceuticals, pigments, and dyes are products from petroleum.