Oil from coal:

Oil from coal:

As petroleum price is increasing due to various reasons, the alternative methods of producing oil gained much importance. The most widely known alternatives involve in extracting oil from sources such as Natural gas (methane), coal, oil shale and tar sands. Though some these sources exist in large quantities, it has become a challenge to extract oil economically and without excessively harming environment. Therefore, in this respect, extraction of oil from coal or from natural gas has been significant.

In fact, technology to extract oil from natural gas or from coal was available since the world war – II; but it was not so much significant until the exorbitant hike in international crude oil prices in last decade. During the World war – II, Germany produced some quantity of oil from coal and there after, South Africa (Sasol) was the major country to produce oil from coal, to meet its energy needs during its isolation under Apartheid. As crude oil prices increase, the cost of coal to oil conversion becomes comparatively cheaper. Now, many countries like China, whose coal production is quite substantial but have less reserve of crude oil, have started producing oil from coal. Recently, India has also started thinking of such conversion of their coal to synthetic oil. This conversion process produces low sulfur diesel fuel but also produces large amounts of greenhouse gases.

The Fischer-Tropsch process is well known for conversion of coal to oil. It is a catalyzed chemical reaction in which carbon monoxide (CO) and hydrogen (H2) are converted into liquid hydrocarbons of various forms. Typical catalysts used are based on iron and cobalt. The principal purpose of this process is to produce a synthetic petroleum substitute, typically from coal, natural gas or biomass.

There is another process called Karrick process for conversion of coal to synthetic oil. It is a low temperature carbonization (LTC) of coal, shale, lignite or any carbonaceous materials. These are heated at 360 degree Celsius to 749 degree Celsius, in the absence of air to distill out oil and gas. Recently, China has announced high volume commercial coal liquefaction production by this method.

Pollution from Oil refineries:

Pollution from Oil refineries:

Oil refineries pollute our air, water, and land. Oil refineries cause smog and air pollution. Almost all refineries in every country currently pollute at unacceptable, unhealthy levels. Oil refineries emit about 100 chemicals everyday. These include metals like lead which makes it hard for children to learn. They also include very smaller size dust particles that get deep into our lungs and harm our ability to breathe. Finally, refineries emit many gases like sulfur dioxide (SO2), nitrogen oxide (NO2), carbon dioxide, carbon monoxide, methane, dioxins, hydrogen fluoride, chlorine, benzene and others.

Many of the gases emitted by refineries are harmful to humans, and can cause permanent damage and even death. They can cause respiratory problems (such as asthma, coughing, chest pain, choking, bronchitis), skin irritations, nausea, eye problems, headaches, birth defects, leukemia, and cancers. Young children and the elderly are the worst affected.

Sulfur dioxide (SO2): Crude oil and coal both contain relatively high quantities of sulfur. (Natural gases contain much less sulfur and therefore are safer.) When crude oil or coal is heated at the refinery to produce fuel, the sulfur is converted into a gas called sulfur dioxide. This is a colourless gas with a very strong smell, like rotten eggs.

Bad effects of Sulfur dioxide: Exposure to very high concentrations of SO2 can result in painful irritation of the eyes, nose, mouth and throat, difficulty in breathing, nausea, vomiting, headaches and even death. Some of the health effects from daily exposure to outdoor levels of SO₂ are tight chests, worsening of asthma and lung disease, and narrowing of air passages in the throat and chest. People with asthma are more sensitive to SO2. Exposure to SO2 can provoke asthma attacks. SO2 mixes easily in water, including moisture in the air to form an acid. Acid rain and early morning dew causes much damage to metals, stones, and the environment.

Fugitive emissions are the air pollution which escapes through leaks in the equipment. Very often the amount of pollution coming from fugitive emissions is higher than the amount coming out of the stacks.

Many of the refineries often use low quality crude oil that has high levels of sulfur. When this is refined it produces higher levels of SO2 pollution.

Accidental fires, explosions, and chemical and gas leaks are common at refineries. Such accidents cause higher than usual amounts of pollution, which may result in more acute exposure to pollutants and greater health impacts.

Petroleum / crude oil / natural gas (exploration, production, processing etc.):

Petroleum / crude oil / natural gas (exploration, production, processing etc.):

Petroleum or more commonly known as Crude oil, available naturally below surface of the earth; used by human being as fuel and applicable for production of various chemicals. Modern society heavily depends on Petroleum / crude oil inclusive of natural gas. Crude oil has become most significant fuel and raw material for production of chemicals in present day world. Because of higher demand for hydrocarbons, pressure on exploration, production and further processing of crude oil / natural gas is tremendous and due this the prices of crude oil have touched sky level recently.

The main activities of the petroleum industry are: (a) Exploration of crude oil and natural gas; (b) Production of crude and natural gas; (c) Processing consists of refining crude for gasoline, diesel, lubricants and further production other down stream chemicals by cracking; (d) Marketing and distribution of gasoline, diesel, lubricants and other processed chemicals.

A. Exploration: Petroleum / crude oil / natural gas are extracted mainly from oil wells found in various oil fields spread all over the world. Various methods are employed in exploration of crude and natural gas and to optimize the process techno-economically. Most exploration process depends on highly sophisticated technology to detect and determine the extent of these deposits. Exploration is initiated with gravity survey, magnetic survey to detect large scale features of the sub-surface geology of the area of investigation. More detailed seismic surveys are conducted at the areas of interest (known as leads). Seismic surveys are basically based on the principle of velocity / time taken by sound wave on reflection at various formations of ground strata, as velocity differs at various interfaces. Finally, when a prospect has been identified, evaluated and passes the selection criteria, exploration wells are drilled to know the presence of oil or gas.

B. Oil / gas Production: Next stage after exploration is production or recovery from the oil reservoir identified after exploration. (a) Primary recovery of oil and gas is done when underground pressure in the oil reservoir is sufficient. This pressure forces the oil to bring it to surface. (b) In Secondary oil recovery various techniques are employed, as this is done when pressure is low in the underground oil reservoir. Pumps such as, beam pumps, electrical submersible pumps are used to bring the oil to the surface. Water injection, gas lift (when CO2 or air is used) and natural gas re-injection are some of the methods also applied when required. (c) Tertiary oil recovery is mainly done to maintain recovery from very low pressure oil reservoir; by reduction of viscosity of underground oil by injecting heat, vapour, surfactants, solvents or miscible gases (CO2).

C. Processing of crude: Processing of crude is done in oil refineries; where more useful petroleum products such as gasoline, kerosene, diesel, LPG (liquefied petroleum gas) etc., are produced by a process known as fractional distillation. Products having lower boiling point leaves from top and higher boiling point products leave the fractioning column at the bottom. Therefore, light distillates are LPG, gasoline, naptha; middle distillates are kerosene, diesel and heavy distillates including residuum are fuel oil, lubricating oils, wax and tar.

D. Petroleum is the major source of organic chemicals. In petrochemical industry major chemicals are derived from two constituents of crude oil – Xylene and Naptha. These chemical raw materials are broken down into basic chemicals such as Butadiene. Basic chemicals are made into finished chemicals or chemical products either direct conversion or through an intermediate. For example, butadiene can be directly made into synthetic rubber or butadiene may be processed into an intermediate such as acetone and later acetone may be used for manufacturing other finished polymers.

• Raw material – Naphtha, Xylene.

• Basic chemicals – Butadiene, Ethylene, Propylene etc.

• Intermediates – Acetone, Phenol, Acrylonitrile, Vinyl acetate, Ethanol etc.

• Polymers – PVC, Polyester fiber, Polystyrene, Polyethylene etc.

E. Major Crude oil and natural gas producing countries are: (a) Saudi Arabia (an OPEC country); (b) Russia; (c) USA; (d) Iran (an OPEC country); (e) China; (f) Mexico; (g) Canada; (h) UAE (an OPEC country); (i) Venezuela (an OPEC country); (j) Norway; (k) Kuwait (an OPEC country); (l) Nigeria (an OPEC country); (m) Brazil; (n) Algeria (an OPEC country); (o) Iraq.