Question

Recall the terms "specific enthalpy" and "enthalpy density" from the module on Thermochemistry. How are they different and why must they be considered when choosing a fuel source? 2 Engine "knock" is the sound an engine makes when gasoline ignites too soon in the engine cylinder (possibly due to low octane fuel). Knocking may cause loss of power, overheating and engine damage Knocking may be due to low octane fuel. Why? What is meant by octane rating? (Research!) a. How could the composition of gasoline be altered to increase the ease of starting a car in cold weather? (Research!) b. catalytic converter in your car's engine Research what happens to pollutants in a 3. What are some specific environmental concerns that occur along the pathway of underground reserve to refined petroleum product? 4.

Answer 1

2a.Octane rating is the measure of a fuel's ability to resist "knocking" during combustion, caused by the air and fuel mixture detonating prematurely in the engine.

2b. Basically what happens in cold weather, knocking happens in th car's engine due to air and fuel mixture detonating, giving a single that higher octane number fuel is to be used.

There are basically 2 ways to increase the octane number of the fuel.

1. By addition of special additives to lower down the autoignition property of the fuel

2.Byaddition of higher octane no fuel with normal gasoline.

Methyltertiary-butylether (MTBE) is a common special additive, which is mixed with gasoline to increase the Octane number of the fuel by acting as an oxygenate.

​​​​​​3 catalytic converter basically reduces toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction (an oxidation and a reduction reaction). Catalytic converters are usually used with internal combustion engines fueled by either gasoline or diesel. The incomplete combustion of the fuels in the engine paves a way for production of products like the carbon monoxide, hydrocarbons and particulate matters. A high emission level is therefore a proved result. For the purpose of forcing the fuel to have efficient combustion and for reduction of the emission levels for reducing air pollution a wide range of processes are applicable. These include improvising engine design, fuel pre-treatment etc. Among these wide ranges of options available catalytic converter is found to be a better way for establishing an efficient combustion in the controller engine of the vehicle. Usage of noble group metal is an effective way for effective combustion like the platinum group metal serves way good for reducing the exhausts.

4. Toxicity

Petroleum is a complex mixture of many components . These components include straight chained , branched , cyclic , monocyclic aromaticand polycyclic aromatic hydrocarbons. The toxicity of oils can be understood using the toxic potential or the toxicity of each individual component of oil at the water solubility of that component.There are many methods that can be used to measure the toxicity of crude oil and other petroleum related products. Certain studies analyzing levels of toxicity can use the target lipid model or colorimetric analysis using colored-dyes in order to assess toxicity and biodegradability.

Different oils and petroleum-related products have different levels of toxicity. Levels of toxicity are influenced by many factors such as weathering, solubility, as well as chemical properties such as persistence. Increased weathering tends to decrease levels of toxicity as more soluble and lower molecular weight substances are removed.Highly soluble substances tend to have higher levels of toxicity than substances that are not very soluble in water. Generally oils that have longer carbon chains and with more benzene rings have higher levels of toxicity. Benzene is the petroleum-related product with the highest level of toxicity. Other substances other than benzene which are highly toxic are toluene, methylbenzene and xylenes (BETX).Substances with the lowest toxicity are crude oil and motor oil.

Despite varying levels of toxicity amongst different variants of oil , all petroleum -derived products have adverse impacts on human health and the ecosystem. Examples of adverse effects are oil emulsions in digestive systems in certain mammals might result in decreased ability to digest nutrients that might lead to death of certain mammals. Further symptoms include capillary ruptures and hemorrhages. Ecosystem food chains can be affected due to a decrease in algaeproductivity therefore threatening certain species. Oil is "acutely lethal" to fish - that is, it kills fish quickly, at a concentration of 4000 parts per million (ppm) (0.4%). The toxicity of petroleum related products threaten human health. Many compounds found in oil are highly toxic and can cause cancer (carcinogenic) as well as other diseases.Studies in Taiwan link proximity to oil refineries to premature births.Crude oil and petroleum distillates cause birth defects.

Benzene is present in both crude oil and gasoline and is known to cause leukaemia in humans.The compound is also known to lower the white blood cell count in humans, which would leave people exposed to it more susceptible to infections."Studies have linked benzene exposure in the mere parts per billion (ppb) range to terminal leukemia, Hodgkin's lymphoma, and other blood and immune system diseases within 5-15 years of exposure."

Emissions from the petroleum industry occur in every chain of the oil-producing process from the extraction to the consumption phase . In the extraction phase there are emissions of not only carbon dioxide but various other pollutants like nitrous oxides and aerosols.^[8] Certain by-products include carbon monoxide and methanol. When oil or petroleum distillates are combusted, usually the combustion is not complete and the chemical reaction leaves by-products which are not water or carbon dioxide. However, despite the large amounts of pollutants, there is uncertainty about the amount and concentration of certain pollutants. the refinement stages of petroleum also contributes to large amounts of pollution in urban areas. This increase in pollution has adverse effects on human health due to the toxicity of oil. A study investigating the effects of oil refineries in Taiwan. The study found an increased occurrence of premature births in mothers that lived in close proximity to oil refineries than mothers who lived away from oil refineries. There were also differences observed in sex ratios and the birth weight of the children. Also, fine particulates of soot blacken humans' and other animals' lungs and cause heart problems or death. Soot is cancercausing (carcinogenic)

Acid rain

The combustion process of petroleum , coal , and wood is responsible for increased occurrence of acid rain. Combustion causes an increased amount of nitrous oxide s, along with sulfur dioxide from the sulfur in the oil. These by-products combine with water in the atmosphere to create acid rain. The increased concentrations of nitrates and other acidic substances have significant effects on the pH levels of rainfall. Data samples analyzed from the United States and Europe from the past 100 years and showed an increase in nitrous oxide emissions from combustion. The emissions were large enough to acidify the rainfall. The acid rain has adverse impacts on the larger ecosystem. For example acid rain can kill trees , acidified lakes and kill fish. Coral reefs are also destroyed from the acidified rainfall of acid rain. Acid rain also leads to the corrosion of machinery and structures (large amounts of capital) and to the slow destruction of archeological structures like the marble ruins of Rome and Greece.

Climate change

The combustion of petroleum causes an increased amount of carbon dioxide emissions as well as other greenhouse gases. The first study on the effects of carbon dioxide was studied by Swedish Nobel chemist Svante Arrhenius.His mathematical model showed that an increase of carbon dioxide results in an increase in surface temperatures, therefore both factors are correlated. The combustion of petroleum for transport, industrial and domestic use is one of the major forms of air pollution. The ultimate by-product of oil combustion is carbon dioxide, however, there are other by-products such as carbon monoxide and nitrates. These by-products react with the atmosphere to produce ozone and other greenhouse gases. The increased pollution has consequences on global temperature. The atmosphere reflects 30% of the incoming longwave radiation back and keeps 70% of it for warmth. However, an increased carbon dioxide concentration in the atmosphere acts as a "blanket" to increased heat. Therefore, more longwave radiation is trapped in the atmosphere when there is a higher concentration of carbon dioxide and this trapping results in increased surface temperatures. IPCC (2007) states that the climate system will heat up by 3 degrees Celsius for a doubling of carbon dioxide .The warming of the temperatures will have massive impacts on rainfall patterns, retreat of glaciers, and the average sea levels.

Oil spills

An oil spill is the release of a liquid petroleumhydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is usually applied to marineoil spills, where oil is released into the ocean or coastal waters, but spills may also occur on land. Oil spills may be due to releases of crude oil from tankers, pipelines, railcars, offshore platforms, drilling rigs and wells, as well as spills of refined petroleum products (such as gasoline, diesel) and their by-products, heavier fuels used by large ships such as bunker fuel, or the spill of any oily refuse or waste oil.

Major oil spills include, Lakeview Gusher, Gulf War oil spill, and the Deepwater Horizon oil spill. Spilt oil penetrates into the structure of the plumage of birds and the fur of mammals, reducing its insulating ability, and making them more vulnerable to temperature fluctuations and much less buoyant in the water. Cleanup and recovery from an oil spill is difficult and depends upon many factors, including the type of oil spilled, the temperature of the water (affecting evaporation and biodegradation), and the types of shorelines and beaches involved.Other factors influencing the rate of long-term contamination is the continuous inputs of petroleum residues and the rate at which the environment can clean itself.Spills may take weeks, months or even years to clean up.

Volatile organic compounds

Volatile organic compounds (VOCs) are gases or vapours emitted by various solids and liquids."^[14]Petroleum hydrocarbons such as gasoline, diesel, or jet fuel intruding into indoor spaces from underground storage tanks or brownfields threaten safety (e.g., explosive potential) and causes adverse health effects from inhalation.

Waste oil

Waste oil in the form of motor oil

Waste oil is oil containing not only breakdown products but also impurities from use. Some examples of waste oil are used oils such as hydraulic oil, transmission oil, brake fluids, motor oil, crankcase oil, gear box oil and synthetic oil.^[16]Many of the same problems associated with natural petroleum exist with waste oil. When waste oil from vehicles drips out engines over streets and roads, the oil travels into the water table bringing with it such toxins as benzene. This poisons both soil and drinking water. Runoff from storms carries waste oil into rivers and oceans, poisoning them as well.