Liquefied Petroleum Gas Lpg Engineering Essay

Liquefied Petroleum Gas Lpg Engineering Essay Liquefied Petroleum Gas is an important source of energy for millions of people around the world. LPG consists mainly of gases at atmospheric temperature and pressure (propane and butane), which when subjected to modest pressure or refrigeration can liquefy. This makes it possible to transport and store as liquid in pressurized cylinders and containers, which must be safely and carefully handled. Definition: Liquefied Petroleum Gas (LPG) can be simply described as hydrocarbons that exist as vapours under ambient conditions of temperature and pressure, but can be liquefied by the application of moderate pressure. When gas is liquefied, the volume occupied by the vapour considerably decreases, thus the liquid formed requires less storage space. The material is therefore stored and distributed in the liquid phase in pressurized containers and systems and is finally allowed to return to the vapour phase at the point of eventual utilization. Sources of LPG: LPG as the name suggests, consists mainly of a mixture of hydrocarbons (Propane and Butane) with a little proportion of unsaturates (Propylene and Butylene). These hydrocarbons and unsaturates (LPG) can be produced through two main sources which are: Wet Natural Gas, which consists entirely of saturated hydrocarbons (Propane and Butane) and can be found in oil or gas fields, being removed as condensable products from natural gas and also extracts from crude oil during the stabilization process applied in order to reduce the vapour pressure prior to shipment; Refining process to remove impurities like moisture and sulphur compounds (hydrogen sulphide and mercaptans), which may lead to clogging of valves and corrosion. However, due to the odourless nature of LPG, ethyl mercaptan which has a unique odour, is added to alert the user of LPG incase a leak takes place. The product of crude oil refining fall into three main categories: The permanent gases, Methane and Ethane which remain gaseous regardless of pressure, unless refrigerated. Hydrocarbons having five or more carbon atoms per molecule. They are liquid or solid at atmospheric temperature and pressure and account for most of the crude oil refined. Propane, Butane and Isobutane, together with Propylene, Butylene and Isobutylene have three or four carbon atoms per molecule. All have the special property of becoming liquid at atmospheric temperature if moderately compressed and reverting to gases when the pressure is sufficiently reduced. C:UsersMr TDesktopIMAG0168.jpg Properties of Liquefied Petroleum Gas (LPG) Vapour Pressure Vapour pressure is a measure of the volatility of the gas and where vapour exists in conjunction with the liquid phase is referred to as the saturation vapour pressure. At the boiling point it is equal to atmospheric pressure and increases as the temperature rises to the critical. Propane with its lower boiling point thus exerts a greater vapour pressure under identical conditions than butane. Knowledge of the vapour pressure of a gas is thus essential in order to be able to specify the design conditions for the pressurized system. It is also required to enable the gas offtake rates by natural vapourization to be calculated. In practical terms, systems are often specifically designed to be suitable for either butane or propane which thus precludes a butane system from being used for propane, but enables the propane system to be classed as dual purpose. G:DCIM100MEDIAIMAG0198.jpg Boiling Points of LPG The constituent gases found in a commercial LPG mixture all have very low boiling points and will thus normally exist in the vapour phase, under atmospheric conditions, unless they have been liquefied or refrigerated. Where the gases are held at a temperature at or below their boiling point, the vapour pressure will be equal to or less than atmospheric. This property has led to the development of large scale storage at marine terminals where the product is held in refrigerated form in what is essentially a non-pressurized system. Above ambient temperature, the gases exert an increasing vapour pressure, thus increasing the pressure required for liquefaction. This pressure continues to increase until the critical temperature is reached, (96.67oC for propane; 152.03oC for n-butane), above which temperature of the gases cease to exist in the liquid phase even if further pressure is applied. Latent Heat of LPG The latent heat of a liquid product is the quantity of heat absorbed to enable vapourization to occur. In the event of liquid LPG being allowed to vapourize naturally, the latent heat required is taken from itself and its immediate surroundings at the same time, causing a drop in temperature. The process is known as auto-refrigeration. Very low temperatures can be achieved with propane under such conditions; therefore in order to avoid operators receiving severe cold burns, protective clothing is required. Specific Volume, Relative Density LPGs exist as heavy gases approximately 1.5 2.0 times the density of air in vapour phase. They reduce in volume considerably on liquefaction (ratio of gas volume to liquid volume at 15.6oC/1016mbar is 233 for butane and 274 for propane) to exist as a clear liquid which is approximately half the weight of water (Propane 0.50 0.51, Butane 0.57 0.58). It can thus be seen that LPG vapours heavier than air will tend to cling to the ground seeking to enter trenches, drains and other low areas, which could make it take considerably longer time to disperse. Leaking liquid phase LPG will rapidly expand to around 250 times its own volume, therefore creating a greater risk than would occur with a similar sized vapour leakage. Where temperature conditions permit the existence of free liquid from a leakage, the product will float on any water present. This normally occurs with butane in freezing conditions and a typical scenario would occur during firefighting operations. Coefficient of Cubical Expansion of Liquid Liquid phase LPG expands considerably when its temperature increases. The coefficients of cubical expansion at 15oC are approximately 0.0016 per oC for propane and 0.0011 per oC for butane. These values are around 4 times the equivalent for fuel oil, 10 times that for water and 100 times that for steel. This high rate of expansion has to be taken into consideration when specifying the maximum quantity of LPG permitted to be filled into any pressure vessel, ie the filling ratio defined by codes of practice for different specification of LPGs under different ambient conditions. Because the filling ratio precautions taken to prevent the hydraulic filling of storage systems cannot be extended to the connecting liquid phase pipework, these parts of the system are protected by the provision of small hydrostatic relief valves situated in all areas where the liquid LPG can be trapped between closed valves. Limits of Flammability Gaseous fuels will only burn when mixed with air in proportions which lie between two well defined limits, known as the lower and upper limits of flammability. The lower limit being the smallest quantity of combustible gas which, when mixed with a given quantity of air (or O2) will support self-propagating flame. A leak of 1m3 of liquefied propane will produce 274m3 of propane vapour, which will cause immediate entrainment of air and progressive dilution of the concentration. When the upper limit of 10% is reached, the propane/air mixture becomes flammable (ie when the propane entrains, 274 10 = 2740m3 of air). The mixture only becomes flammable when the lower limit of 2% is reached (ie when the propane entrains 274 50 = 13,700m3) of air. Therefore, should a leak of propane occur, the propane/air mixture will be flammable and hence extremely dangerous until it has been diluted with more than 13,700m3 air per m3 of propane leakage. The following are the limits of flammability of LPG and some other fuels: Gas Lower Limit Upper Limit Commercial Propane 2.0 10.0 Commercial Butane 1.8 9.0 Natural Gas 5.0 15.0 Coal Gas 5.0 40.0 C:UsersMr TDesktopIMAG0189.jpg

Beauty Pageants Aren’t Exploitive

Beauty Pageants aren't Exploitive All kinds of beauty pageants are held every year. Many girls are dreaming to participate in them to show theirselves and achieve what they want. In order to get the chance, they may use different ways. Therefore, some people think that beauty pageants are kind of exploitive, which I am disagree with . Proponents of this idea claim that looking good is the standard you get into through a beauty pageant but ignore the deeper meanings of women.There is nothing wrong with judging people primarily on their physical conditions. We do this all the time in competitive sport, where fitness and strength are major determinants of success. Every competition, of every kind, values certain qualities over others. Similarly, we can give a prize to a beautiful woman for her beauty without implying that beauty is all that matters about anyone. People who against it think that beauty pageants make harmful attitudes to women.In a society which there really are fewer opp ortunities for women than for men, beauty pageants give women a chance to get noticed and to improve their situations. Winning a beauty pageant can be a route to success. Some people maybe totally disagree with it. They put forward this idea because in order to participate in it, some girls may try all kinds of extreme ways to keep fit and it's harmful to them. Entering a beauty pageant and performing well requires a great deal of qualities which are both very useful to possess.When there is a stage full of good-looking young women, the winner must be someone with personality and confidence, but not just an attractive appearance. Alex Comfort said:†A woman's greatest asset is her beauty. Though the beauty pageant do have something bad for the beauty in the past, it isn't exploitive. It has changed as the society is developing. It can help you succeed, know yourself and show your charm.

The Motif Of Water On Jay Gatsby - 1898 Words

The Motif of Water on Jay Gatsby: A Boat Pushed Back Against the Current In The Great Gatsby, by F. Scott Fitzgerald, the motif of water is prevalent throughout the entirety of the story, seen frequently when Jay Gatsby, a prominent character, is present. Gatsby is a rich man who lives on the same island in New York as the main character Nick Carraway, who has just moved from the West in order to pursue a career in bonds. His cousin, Daisy, lives across the bay from the houses of Nick and Gatsby with her husband Tom, a former schoolmate of Nick. Nick becomes close to Gatsby over the course of the summer, as well as Jordan Baker, a friend of Daisy’s. Gatsby contacts him through her and she also tells Nick about Gatsby’s past and later Gatsby explains that he was once in love with Daisy when they both lived in Kentucky and wants to be with her again. Through Nick, Gatsby and Daisy meet and fall in love again, while at the same time Tom has an affair with a woman from the city, Myrtle. One day, Tom, Nick, Daisy, Gatsby, and Jordan drive to New York and Tom discovers that Gatsby and Daisy have an affair. Distressed, Gatsby and Daisy leave in Tom’s car and on the way back Daisy runs over Tom’s mistress, killing her. Eventually Myrtle’s husband discovers through Tom that it was Gatsby who killed her and goes to seek revenge. Gatsby is killed by Myrtle’s husband while lounging in his pool that was about to be drained, signaling the end of the novel. In The Great Gatsby, the authorShow MoreRelatedsparknotes vs cliffnotes830 Words   |  4 Pagesthe character and his motives. In analyzing Jay Gatsby, Cliffnotes focuses much more on Gatsby himself and his underlying motives to his character, like â€Å"In assessing Gatsby, one must examine his blind pursuit of Daisy.† (Cliffnotes). Sparknotes focuses not only on the overall character of Jay Gatsby, but also analyzes how his character compares with other characters, and how his character relates to the author. 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Scott Fitzgerald1438 Words   |  6 Pagesand Fallen Themes In The Great Gatsby, Fitzgerald employs the use of characters, themes, and symbolism to convey the idea of the American Dream and its corruption through the aspects of wealth, family, and status. In regards to wealth and success, Fitzgerald makes clear the growing corruption of the American Dream by using Gatsby himself as a symbol for the corrupted dream throughout the text. In addition, when portraying the family the characters in Great Gatsby are used to expose the corruptionRead MoreThe American Dream1823 Words   |  8 Pageshimself an expert on the latest crazes in fashion, contemporary lingo, and popular pastimes.† (Marchand) This description shows material success as the model for the American Dream. In his novel The Great Gatsby, Fitzgerald reveals the characterization of his characters through the use of symbols and motifs to emphasize the corruption of the American Dream. The eyes of T J Eckleburg represent the loss of moral and social values in America, the hollowness of the American Dream, and the corruption of people

The Struggle Against the Apartheid State of South Africa...

Mandelas childhood was very important in shaping him to be the man he was. His father losing his land in 1919 would have affected Mandelas opinion of how the country works as he grew up, and when he was 16 the main speaker at his circumcision told that Blacks were slaves in their own country. He grew up with the opinion that his country needed a better rule, because of how unfair it was to Black people. His earliest decisions to fight for Black liberation were made here. Another turning point was when Chief Jongintaba died in 1942. He then stayed in Johannesburg instead of moving back to Mqhekezweni, this showed he wanted to make an impact on the country as a whole instead of just his†¦show more content†¦Unity these factions meant that the party could operate more effectively, as was proved when in 1994 Mandela became the first democratically elected president of South Africa. Q2. Explain the part played by external pressure in the fight against apartheid and minority rule in South Africa. From 1960 onwards, when Harold Macmillan made his change of winds speech, the world started to place external pressures on South Africa, and this was one of the main causes of the end of apartheid. Economic sanctions and sporting isolation were the two main subdivisions of external pressure. Sporting isolation made South Africa realise that the minority rule and the apartheid regime was greatly frowned upon by the rest of the world, and caused many Afrikaners to change their attitude to the way the country was being run; this was because they didnt want to be excluded from the rest of the worlds competitions and tournaments solely for their governments issues; it made the Afrikaners feel guilty for the regime ruling South Africa. This attitude would eventually help in ending the apartheid regime. Economic sanctions, however, were much more effective in the ending of minority rule. Foreign countries saw South Africa as a risky country to invest in because the sanctions against South Africa withdrew loans in businesses; businessmen found it harder to have prosperous companiesShow MoreRelated The Role of External Pressure in the Fight Against Apartheid and Minority Rule in South Africa1583 Words   |  7 PagesThe Role of External Pressure in the Fight Against Apartheid and Minority Rule in South Africa External pressure played a very important part in bringing about the end of the apartheid. The embodied rejection of White domination in South Africa, in formations of protests, strikes and demonstrations caused a decade of turbulent mass action in resistance to the imposition of still harsher forms of segregation and oppression. The Defiance Campaign of 1952 carried mass mobilisationRead MoreThe Impact of Music During Apartheid1530 Words   |  7 PagesThe Impact of Music During Apartheid Amandla! A Revolution in Four-Part Harmony is a 2002 documentary film directed by Lee Hirsch that describes the struggle the black South Africans faced during apartheid. Activists and musicians discuss the days of apartheid. The film has a collection of musical performances, interviews, and historical footage. Amandla is a Zulu and Xhosa word that means power. It was a common rally word used in resistance to Apartheid. The black South Africans also used musicRead MoreEssay on Sarafina604 Words   |  3 PagesSarafina Sarafina! is the story of the struggle for freedom of non-European school children in Soweto, South Africa. The story takes place during the time of the Apartheid just before Nelson Mandela was released in 1990 and the Apartheid ended. The Apartheid was a policy of strict racial segregation and political and economic discrimination against non-whites in the Republic of South Africa (WWWebster Dictionary). Segregation and discrimination against non-whites was imposed in housing, employmentRead MoreThe Black Consciousness Movement And The Struggle For Racial Equality1598 Words   |  7 PagesThe brutal system of legislation, apartheid, introduced by the Nationalist Party within South Africa in 1948 saw a colossal divide in national identity. The rigid policy of segregation and institutionalised racial discrimination of the blacks or â€Å"bantu’s† by white supremacy caused rising and consistent opposition in the form of various groups. Organisations such as the South African School’s Associations, African National Congress, and Black People’s Convention campaigned side by side for black equalityRead MoreThe Apartheid Of South Africa1333 Words   |  6 Pageshistory of South Africa all we could see is racial discrimination. Africa was all in control of Whites till 1994. South Africa got free from racial discrimination when Nelson Mandela took a step became the first black prime minister of South Africa. Contemporary South Africa is now economically strong and it is completely a racial free state. The contemporary South Africa is now in race with every state in every field. Before 1994 South Africa was completely under control of Apartheid. WHO IS APARTHEIDRead MoreOpposition to Apartheid1631 Words   |  7 PagesThe South African Apartheid, instituted in 1948 by the country’s Afrikaner National Party, was legalized segregation on the basis of race, and is a system comparable to the segregation of African Americans in the United States. Non-whites - including blacks, Indians, and people of color in general- were prohibited from engaging in any activities specific to whites and prohibited from engaging in interracial marriages, receiving higher education, and obtaining certain jobs. The National Party’s classificationRead MoreThe Role of Nelson Mandela in Ending Apartheid in South Africa783 Words   |  4 Pages Nelson Mandela’s role in bringing Apartheid to an end was very important, however, there were many other factors that contributed to the ending of Apartheid. The African National Congress, also known as the ANC, was a major factor in ending Apartheid. Even when the ANC became illegal in South Africa it moved to continue its work against Apartheid. In 1940 Dr. A. B. Xuma became president of the ANC; he rescued a struggling organisation. In 1944 he reorganisedRead More Apartheid in South Africa Essay1551 Words   |  7 PagesRacism is mans gravest threat to man...the maximum of hatred for a minimum reason. -- Abraham Heschel The Apartheid. An experience that left thousands of Black South Africans without rights, property, and even lives. Although original in its name, the ideas were not original in itself. The ordeal dates back to 1652 when the early Dutch settlers moved into Black territory on a mission to change the order of civilization (Rotberg 18). Boers (Rotberg; 18) as the Dutch called themselves, tookRead MoreNelson Mandela s President Of South Africa1309 Words   |  6 Pagestirelessly to ensure freedom for not just black majority in south africa, but for all races. He has endured many things in his quest for peace, including being put on trial and going to jail multiple times. He is well known in his country as a hero who strived for peace. His fight eventually led him to becoming the first democratically elected president of South Africa. His legacy of courage, leadership, and bravery lives on in the people of South Africa forever. Nelson Mandela was born RolihlahlaRead MoreEssay about Politics and Apartheid1045 Words   |  5 Pagesbones, these people were living skeletons. The dark-skinned citizens of South Africa could attribute their misfortune due to the state of politics in South Africa, where prejudice against dark skinned people ran as rampant as disease and poverty. Due to politics working against dark-skinned people beginning three years after South Africa gained its independence, apartheid was established and fought for by racists and against by activists until it was ended in 1991. The story of Kaffir Boy filled