Polyethene Essays - Commodity Chemicals, Packaging Materials

Polyethene Polyethylene also known as polyethylene or polythene, was the first of the polymers to be discovered. Polyethene is a polymer produced by reacting oxygen and ethene, in this reaction the small ethene molecules attach together to form long chain polymer molecules. This process is known as addition polymerisation. Polyethene in our world today has many uses, some of these are: ? mouldings-plastic bottles, lids and caps, different types of containers. ? films-glad wrap and various plastic bags. ? cable coverings-various pipes and insulating wire and cables As you can see polyethene has a huge variety of both domestic and industrial uses, this is fairly impressive when you see that polyethene has only been around sense 1933. Polyethene is a thermoplastic material which is often described as wax-like it is extremely tough and is has an excellent chemical resistance. It is also less dense than water and is the simplest polymer, these attributes lead to polythene being an extremely useful substance. Ethene (C2H4), is a simple hydrocarbon molecule which consists of 2 carbon atoms and 4 hydrogen atoms. Ethene's main use is in the production of polythene yet it is one of the most widely used petrochemicals in the world. Ethene is an unsaturated colourless gas which can be ignited in the presence of oxygen. Below is a diagram of ethene: Polyethene is produced by allowing the free roaming ethene gas molecules to bond together to form long chain polyethene molecules. In order for this to work a catalyst must be used, a catalyst is a substance that can alter the rate of a chemical reaction without undergoing any chemical change itself. During this process thousands of ethene molecules bond to from each molecule of polyethene. Polyethene is simply a set of ethene molecules bonded together to form a chain, these chains can often stretch up to many many times longer than the original ethene molecule. Below is a diagram of polyethene: Although normally ethene monomers have little attraction for one another, yet the polyethene molecules have a strong attraction for one another. When polyethene molecules are attracted and bond high-density polyethene is formed, thus polyethene is either formed by low-density or high-density polymerisation. Ethene can undergo the process called polymerisation due to the fact that it is unsaturated and because it has a double bond between its two carbon atoms. Both High-density and low-density polyethene have different uses. Low-density polyethene is used in the production of products such as various bags, plastic bottles, cling wraps, and insulating cables. Low pressure polymerisation with the use of certain catalysts; has meant that the process of polymerization can be achieved at fairly low pressure (20 atmospheres or 2000 kPa) and at temperatures of approximately 100?C. The reactor itself contains a polyethene bed placed on a perforated plate. It works by allowing the recycled gas to enter near its base, the gas then passes through the plate and pushes up through the bed causing it to bubble. Finally the catalyst converts the ethene to polyethene, once the polyethene is cooled it forms a fine powder called 'fluff' which is then collected and transported to a storage bin. Any ethene gas which has not reacted passes through a compressor and then a cooler, and is processed again. High-density polyethene is used to produce items such as lids, caps, baskets, bowls and large containers such as garbage bins. These polyethene products are created in what is know as high-pressure polymerisation, this is a process that was originally used before low-pressure polymerisation was discovered and thus it is a fairly simple process. Firstly Ethene gas is compressed and liquefied, from here it is pumped into a large reactor at a pressure of up to 2660 atmospheres(266 Mpa). Amongst this oxygen and peroxides are pumped in to initiate the polymerisation reaction. This process generates a huge amount of heat so the most complex part of the system is the cooling facilities. The many products of polyethene which are most commonly used are generally manufactured using any of these five different techniques Extrusion - film, this technique is used for the production of items such as plastic bags such as garbage bags and glad wrap. These are the most common applications, while there are many others these are the best examples of this technique. This final product is achieved by blowing air into a tube of molten plastic this allows for extremely fine layers of the plastic to form. Blow moulding, this is used to make plastic bottles and some motor oils. This technique is much like the previous

Become a Networking Expert by Following This 5 Step Plan

Become a Networking Expert by Following This 5 Step Plan It would be great if we could get a job from the safety of our couches, in our pajamas, without having to leave the house. Unfortunately, almost no one actually gets hired from online applications. Networking is still the best way to get your foot in the door. And networking requires both wearing pants- and social skills. Here are five things you absolutely have to do to be one step closer to becoming a networking expert. Prepare in advanceHave a plan before you walk up to the big fish and try to reel them in. Figure out whom you might have the opportunity to meet at any particular event, then learn as much as you can about them. Figure out what you should emphasize to each, and how best to frame yourself. Practice your pitch. Bring plenty of business cards.Ease UpThis isn’t the same as selling used cars. You’re not the Avon lady. Most sentient humans will appreciate a little more sincerity. Remember- you don’t have to be in sales mode all the time in every encou nter. Try connecting on a personal level first and letting the conversation evolve naturally before you start thrusting your business cards in people’s faces.Show upAs great as it would be to send somebody to network for us, this just doesn’t work. Don’t send a friend or colleague- or your sister- to shake hands with that particular hiring manager if you can’t attend yourself. Send a professionally worded email explaining how much you’d like to meet and see if you can’t find another opportunity instead.Expand your reachDon’t play it safe. Your contacts, no matter how many you have, are not enough. It will always be beneficial to keep growing your network and making more connections. You never know when you will need them. Get out there and mingle!Follow upThis is perhaps the most important step in the whole process. Whether you send a handwritten note or an email, it’s absolutely crucial to follow up. It shows your interest and your professionalism, and has the added benefit of reminding that connection you exist!

Naming, Taxonomy, Classification of viruses Essay

Naming, Taxonomy, Classification of viruses - Essay Example Other examples of pathogens include the nematodes, fungi and bacteria. In Biology, the term nomenclature is used to refer to the naming the various taxonomic groups as per the international conventions. When it comes to the naming of viruses, there is a special body tasked with this responsibility. It is called the International Committee on Taxonomy of Viruses (ICTV), (formerly known as the International Committee on the Nomenclature of Viruses) which was established in 1966. It is the committee of the Virology Division of the International Union of Microbiological Societies. Unlike the nomenclature of other living organisms, viruses are not named with respect to Carolus Linnaeus’ Latinized binomial system. They are named by use of words of English origin new international taxonomic names this is according to the International Committee on Taxonomy of Viruses, R. I. B. Francki (1991). Rule No. 10 – rules pertaining the spelling of names with respect to the language used are outlined in Section 6 of Chapter 3 of the proposed viral nomenclature. This is as per the minutes of the meeting held in Moscow in 1966, Rule No. 13 - where agreed upon, the symbols may come after an abbreviation of a Latin name of a given host genus of a particular host, but if need be, a full name instead of the abbreviation may still be used, When it comes to the taxonomy of viruses, which is the classification of viruses into various taxonomic groups, the International Committee n Taxonomy of Viruses came up with a unified taxonomy. The classification system makes use of the below ranked taxons; The current list from the International Committee on Taxonomy of Viruses (ICTV) indicates that there are three (3) viral orders namely; Caudovirales – these are the tailed double stranded deoxyribonucleic acid (dsDNA) phages, Mononegavirales – these are the ones having enveloped globular virons bearing similar single stranded negative ribonucleic acid (ss (-) RNA) genomes and

International Human resources management Essay Example | Topics and Well Written Essays - 2000 words

International Human resources management - Essay Example II. LITERATURE REVIEW i. Provides what other researchers have discussed about the factors taken into considerations before setting wage such as setting the wage high in order to motivate and attract good labor force. ii. Labor market conditions or the bargaining power of employees or existing laws of labor unions can influence wage payment. iii. The empirical research carried out provided the theoretical prediction that the bargaining wage tends to be lower in places where there are high rate of unemployment. III. FACTORS TO CONSIDER IN SETTING THE WAGES a) British expatriate managers and engineers i. Availability of expatriate managers and engineers capable of fulfilling the obligations and responsibilities of the job ii. Determining the level of job demand for prospective employees or unemployment level in a certain country iii. Employment setting and organizational needs. b) Local manager’s engineers and manufacturing staff i. The wage compensation laws prevailing in a give n area and the attractiveness of the community ii. The cost of living and benefits that the company would realize iii. Performing job evaluation IV. CONCLUSION i. Provides the summary of the factors that IHRM should take into considerations before setting wage payment International Human Resources Management Introduction The International human resource directors and other top management teams of multinational companies have nowadays realized that globalization is the most critical problems many multinational enterprises are facing today. They also acknowledge that it has become difficult to determine the internalization strategies and factors that they will employ in setting wages for their employees. The IHRM director of a British Multi-National Food Processing Company, which is now planning to open new sites in Australia, Russia and India need to evaluate effective factors for setting wage payment for their employees. Many companies get stuck in the job evaluation process because of the complexity nature of job evaluation process. Many grading and wage payment structures for varied employment aspects have evolved over time and this can be hard for IHRM director to justify why one job is graded or paid higher than the other job. It is vital to employ unique methods for job evaluation, identify effective factors for setting wage payment of expatriate managers, engineers, manager’s engenders and manufacturing staffs. Therefore, before determining wage payment of employees, it is crucial to determine the organizational needs by carrying out job evaluation, job relevant skills, work experience for applicants and understand the economic conditions of the region in which the company will function. Literature Review Many multinational companies evaluate varied factors before making a decision of what to pay the new recruited employees. Thus, varied literatures have attempted to reveal the way many companies carry out labor evaluation process or employ varied factors when setting the wages for their employees. When setting the level of monetary compensation of employees, one need to take into consideration varied factors. Snell and Bohlander (2010, p. 121) argue that one of the first factors that should be taken into considerations when setting wage is setting the wage high in order to motivate and attract good labor force. The wage should be equitable meaning that it should accurately reflect the value of the labor performance. Sparrow, Brewster and Harris 2004, p.49)

Political Science 120 Essay Example | Topics and Well Written Essays - 750 words

Political Science 120 - Essay Example Firstly, the legislature exercises checks and balances on the executive by shutting down presidential vetoes through voting against them with a two-thirds majority. The legislature checks on the executive by either approving presidential appointments or new treaties. The legislature also has the power of impeaching a sitting president out of office by passing a vote of no confidence. On the other hand, the legislature checks on the judiciary by either approving or declining appointed judges, creating lower courts or impeaching a judge out of office. Secondly, the judiciary exercises checks on the legislative branch through declaring formulated laws as unconstitutional. On the other hand, the Judiciary, through the judicial review checks on the executive by declaring some deeds by the executive as unconstitutional. Thirdly, the executive exercises checks on the judiciary by nominating the persons to be appointed in the Supreme courts and the persons to be appointed in the federal cour ts. Additionally, the executive will check on the legislature by exercising a veto power against some legislations and recalling congressional sittings. The system of checks and balances had the objective of ensuring that no single branch of government becomes powerful that the other, which would lead to oppression of the citizens and a lack of justice. The system of checks and balances was put in the constitution with the intention of seeing to it that the rule of law prevails (Brannen & Lawrence, 2005). Question # 2 Cooperative Federalism Through Cooperative Federalism, the responsibility of governing people in a society is shared by the state and the national government. The different levels of government consult on which level is best suited on taking a particular responsibility in relation to governing and policy formulation. Cooperative federalism focuses on the idea that the overall governance of a nation is a partnership between the state and the national government. In esse nce, cooperative governance entails different levels of government exercising power in the same area (Hueglin & Fenna, 2006). Federalism works in a manner that the state governments are limited in terms of the powers that they can exercise in their states. This is contrary to the power that the national government can exercise. For instance, the state government cannot coin out currency, declare war, formulate immigration laws or raise an army. However, the national government has the power to coin out currency, declare war, formulate immigration laws and raise an army or a navy (Hueglin & Fenna, 2006). Cooperative federalism is different from dual federalism in that, in dual federalism the state and national governments are sovereign and equal partners. In dual federalism, a lot of power is directed to the states while the national government’s power is only spelt by the constitution. In cooperative federalism, the national government, through the constitution under article I in section 8 can exercise powers, which the state government cannot. The above fact was not possible under dual federalism (Hueglin & Fenna, 2006). Cooperative federalism came as a result of Congress’s intention of regulating trade and commerce in the whole of the United States. Another reason that led to cooperative federalism is the idea of eliminating the aspect of competition between the state governm

Small Scale GTL (STG Plus) Plant

Small Scale GTL (STG Plus) Plant Course: Natural Gas Processing Technology (ENCH 609, Winter 2017) PROJECT TITLE GTL: Syngas to Gasoline (STG Plus) Professor: Dr. Nashaat Nassar List of figures and tables: Fig 1. Schematic sketch of the STG+ system (from Primus Green Energy TM) .. (6) Fig 2. Sensitivity Analysis for case 62.5 MMSCFD (14) Table 1. Economic Indicators for project evaluation (Detail calculation in Appendix).. (15) Appendix: Fig 1. Operating GTL plants on the world map [The Oil Gas Year, 2015] . (21) Fig 2. Simulation flow chart developed for the project (from Aspen plus V 7.2 Microsoft Visio 2010) (22) Table 1: Used compounds and Values of yields for reactor 4 in the model . (19-20) Table 2: Economic Evaluation for case 1: 10 MMSCFD ..(23) Table 3: Economic Evaluation for Case 2: 62.45 MMSCFD (24) Table 4: Mass balance of streams 1-22 for Case 1: 10 MMSCFD .(25-26) Table 5: Mass balance of streams 1-22 for Case 2: 62.45 MMSCFD .. (27-28) Abstract: The worlds energy demand is growing exponentially and to meet this demand, bringing new supply sources to the market is extremely critical. Natural gas resources are plentiful, geographically diverse and currently also the cleanest burning fossil fuel. Gas to Liquids (GTL) is a chemical process that transforms natural gas or other gaseous hydrocarbons into high quality liquid products that would otherwise be produced from crude oil [Shell Global]. GTL creates an additional opportunity to monetize a countrys resource of natural gas by turning them into high quality liquid fuels. GTL products are colorless and odorless hydrocarbons with very low level of impurities. The purpose of this project is to simulate a small scale GTL (STG Plus) plant that converts 10 MMSCFD of rich-methane natural gas into 672 BBL/day of gasoline. The first step of the STG Plus process is called steam reforming and it consists of the reaction between the methane in the natural gas with abundant water. The second step of the process is the reaction between the hydrogen, and the carbon monoxide producing methanol. The methanol thus formed will be converted to dimethyl ether (DME) and finally, the DME will be dehydrated, producing gasoline. The project will also highlight the difference between two major GTL technologies: Fischer Tropsch and STG Plus. An economic evaluation was conducted to check the viability of this process and at 10 MMSCFD conversion of methane; the project proves to be economically profitable, with an NPV value of $14.66M at 10% discount rate. It was also determined that if the production of gasoline increases to over 4,100BBL/day, the profitability of this project will increase significantly. 1.0. Introduction 1.1. GTL Technology and the World Gasoline to Liquid (GTL) is a technology that converts natural gas or other gaseous hydrocarbons into high quality liquid products like gasoline or diesel fuel, otherwise produced from crude oil []. GTL products are colorless and odorless hydrocarbons with very low level of impurities. Refineries can also use GTL to convert some of their gaseous hydrocarbon waste products into valuable fuel oil which can be used to generate income. The worlds first commercial GTL plant was opened by Shell in Bintulu, Malaysia in 1993. In 2011, the largest GTL plant, Pearl GTL was opened in Qatar [Shell Global]. Figure 1 in the Appendix shows all operating GTL plants and their corresponding locations on the world map. 1.2. GTL Origin In 1920s, when Germany found itself short of petroleum but with ample reserves of coal, GTL and Coal-to-Liquids (CTL) technologies were pioneered using a process known as Fischer-Tropsch (F-T) synthesis (Heng et al. 2004). Methanol-to-gasoline (MTG), Mobils synthetic gasoline process, based on the transformation of methanol to hydrocarbons using zeolite catalysts, was the first major synfuel process development in half a century since the development of the Fischer-Tropsch process (Frerich J. Keil, 1998). 1.3. Gas-to-Liquid (GTL) technology Gas to Liquids (GTL) is a refinery process that converts gas or other gaseous hydrocarbons into products with longer carbon chains. Gasoline and diesel fuel are classic examples. Gases with a high concentration of methane are transformed into liquid synthetic fuels following two methods: direct transformation using processes without the presence of catalysts that convert methane to methanol or by using syngas as a midway product, such as in the Fischer Tropsch, Syngas to Gasoline Plus and Mobil processes. This project will focus on designing a small scale Syngas to Gasoline (STG) plus plant that uses methane rich natural gas as feed and converts it to high quality gasoline and other products. 2.0. Syngas-to-Gasoline plus (STG+) process STG+ process was derived from the MTG (Methanol-to-Gasoline) process, which was developed by Mobil in the 1970s. This technology directly converts natural gas-derived syngas into drop-in gasoline and jet fuel through a catalytic thermo-chemical single-loop process that minimizes complexity, improves product quality and yield. The plus in STG+ stands for the alternate end products yielded by the process. The STG+ technology is currently operating by Primus Green Energy company in Hillsborough, New Jersey at pre-commercial scale with a production of 100,000 gallons (approximately) of distinct quality gasoline per year from natural gas with surpassed performance of the STG+ system and catalyst and 720 hours of continuous operation. The STG+ process consists of the following operating steps in one continuous process loop. It comprises of Syngas generation by steam reforming method, four fixed bed reactors in series and a two phase separator. Figure 1: Schematic sketch of the STG+ system (from Primus Green Energy TM) 2.1. Syngas Generation by Steam reforming method The first step in the STG+ process is to convert the natural gas feed into syngas or synthesis gas which is an intermediate gas feed for many different petrochemical processes. This processing basically removes contaminants, such as mercaptans, sulfides, mercury and any others that can compromise the various catalysts performance that are used in the STG+ reactors before it is fed to the syngas generation unit. Either partial oxidation or steam reforming processes are used for syngas production. Steam reforming process is widely used to generate syngas for feedstock in different petrochemical processes. A mixture of hydrogen, carbon monoxide, carbon dioxide, and unconverted methane and steam are formed when methane reacts with steam in the presence of a catalyst such as Nickel or Rhodium at high temperature (800-1000 C), high pressure (20-40 bars) and steam-to-carbon ratio varying between 1.8 and 4 in the steam reforming process which is highly endothermic in nature (Mbodji et al., 2012). The possible reactions are: The steam methane reforming reaction (SMR) CH4 + H2O à ¢Ã¢â‚¬ ¡Ã¢â‚¬Å¾ CO + 3H2 [ΆH = +206 kJ mol-1] (strongly endothermic).. (1) The water-gas shift (WGS) CO + H2O à ¢Ã¢â‚¬ ¡Ã¢â‚¬Å¾ CO2 + H2 [ΆH = -41 kJ mol-1] (moderately exothermic) . (2) The product from the reformer depends on the operating pressure temperature, composition of the feed gas, and the proportion of steam fed to the reactor. The thermodynamics and kinetics of the reaction within the reformer decides the amount of carbon monoxide in the final product from the steam reformer (Larminie Dicks, 2000). 2.2. Reactor 1 (Methanol Synthesis) Centrifugal compressors are used to compress the syngas from reforming unit which enters the reactor 1 containing copper zinc as catalyst and the following reaction occurs. 2H2 + CO à ¢Ã¢â‚¬ ¡Ã¢â‚¬Å¾ CH3OH [ΆH = -92 kJ mol-1] .. (3) Due to the exothermic nature of the reactions, low temperatures favor conversion to methanol and pre-heating of the reactant gas and heating of the boiler feed water are done by this excess heat. The position of the equilibrium depends on the pressure and temperature. The methanol formation is favored by increase in pressure. 2.3. Reactor 2 (Dimethyl Ether (DME) Synthesis) After the crude methanol from reactor 1 is preheated, vaporized and then superheated between 300-320oC in a series of heat exchangers, it is then sent to the dimethyl ether (DME) reactor containing a dehydration catalyst (alumina) where methanol is partially dehydrated to an equilibrium mixture of DME, water and methanol which is a reversible and exothermic reaction. 2CH3OH à ¢Ã¢â‚¬ ¡Ã¢â‚¬Å¾ CH3OCH3 + H2O . (4) 2.4. Reactor 3 (Gasoline Synthesis) In reactor 3, in presence of catalyst the product gas from reactor 2 converts to hydrocarbons including paraffins (alkanes), aromatics, naphthene (cycloalkanes) and olefins (alkenes), mostly from C6 to C10. 2.5. Reactor 4 (Gasoline Treatment)    To have high octane number for synthetic gasoline and desirable volumetric properties, the product from reactor 3 is treated in reactor 4 to reduce the durene (tetra methylbenzene), Iso durene and tri methylbenzene components which have high freezing points. 2.6. Separator Finally, in the reactor 4 two or three phase separation is done to obtain synthetic gasoline comprised of paraffins, aromatics and naphthene, non-condensed gas and water. The non-condensed gas is recycled back to the feed stream for reactor 1 and water is recycled back to the Steam Reformer (Syngas Generation Unit). 3.0. Why STG+? The previous group responsible for GTL used the conventional GTL technology called Fisher Tropsh (FT) in their simulation process. Fischer-Tropsch (FT), which is a technology developed in early 1920s, converts gas into liquid hydrocarbons mainly diesel through a very complex process. While there have been significant improvements on the efficiency and technology of the Fisher-Tropsch process, the industry is in an urgent need of new technologies capable of converting as much gas as possible into liquid fuels in a cheaper and more efficiently manner. As consequence, we decided to apply for our project the novel process called STG+ developed by Primus Energy. The main product of STG+ is gasoline as opposed to diesel. Since the most demanded liquid fuel in Canada, especially in Alberta, is gas, we decided not use FT or any new technology producing diesel. STG+ has numerous advantages over the conventional GTL techniques such as: lower operating and capital costs, higher production, bett er product quality and faster delivery times. The rival technology of STG+ is ExxonMobils MTG process. However, ExxonMobils MTG process has a greater environmental impact and it is not very cost-effective. STG+ process was designed to correct some inefficiencies in the ExxonMobil process . The main correction is the integration of the reactors in a single-loop that increases the production and yields a higher quality of the gasoline with a less environmental impact A key example is integration of the reactors in the STG+ process. 4.0. Project Design/Simulation 4.1. Flowchart Description The lists of components that are considered in the simulation for the STG+ process and the yields in mass base for the fourth reactor (Keil, 2012) are shown in the Appendix (Table 1). The flowchart developed for the STG+ process is shown in the fig. 2 of Appendix. A brief explanation of the flowchart will be done now. First, our feedstock is basically the natural gas. For simplification purposes, our feed of natural gas is basically methane. Another feedstock that this process will have is fresh water. The water will be heated in a heat exchanger (HE-01) and will be mixed with the methane to enter the first reactor (R-01). In this reactor, carbon monoxide, carbon dioxide and hydrogen will be produced, as explained above. The fractional conversion in the first reaction is 83.4% of the methane, the limiting reactant. The conversion in the second reaction is 6% of the carbon monoxide (Choudhary et al, 1992). The exit stream of the reactor R-01 is cooled in a heat exchanger (HE-02), enters a compressor (CP-01) to increase the pressure for the second reaction process and, finally, enters another heat exchanger (HE-03) to adjust the temperature for the ideal temperature in reactor R-02. The operating conditions of this reactor are 69 bar and 380ƚ °C (Wood et al, 2012). In it, basically, the syngas will be consumed to form methanol. The fractional conversion of this reaction is 63.7% of carbon monoxide (Lebarbier et al, 2012). The exit stream of reactor R-02 will pass through a heat exchanger (HE-04) to adjust the temperature of the mixture to enter reactor R-03. The methanol will form dimethyl ether (DME) and water. The operating conditions of this reactor are 12 bar and 325 °C (Wood et al, 2012). The fractional conversion of the methanol for this process is 76% (Kasaie et al, 2010). The stream that comes out of reactor R-03 passes through a heat exchanger (HE-05) to reduce its temperature and then enters a liquid-vapor flash vessel (FV-01). The dimethyl ether along with the non-polar components will come out in the gas stream, while the water will come out in the bottom or liquid stream, which can be sent to the effluent treatment plant. The gas stream will pass through a compressor (CP-02) and then through a heat exchanger (HE-06) to adjust the temperature and pressure for the fourth reaction process in reactor R-04. Basically, in this reactor, the dimethyl ether will be dehydrated in order to break down its molecule into -C2H4- radicals, which will be combined to form bigger molecules, as explained above. Since the reaction process is complex and the number of reactions is big, the stoichiometry of the process will be very complicated. Therefore, this paper only shows the yield in mass basis of each component formed in reactor R-04 (yield per unit mass of tota l feed of components that are not listed as inerts) (Aspentech Support Technology, 2001). Since only the dimethyl ether (DME) is a reactant in reactor R-04, all of the other compounds that enter reactor R-04 are considered inerts. The exit stream of reactor R-04 will pass through a compressor (CP-03) and through a heat exchanger (HE-07) to adjust the pressure and temperature for the last flash vessel (FV-02). This flash vessel is a liquid-liquid-vapor separator that will separate on the top the gas and lightest products. The middle liquid stream will be the gasoline formed (main stream) and the bottom liquid stream will be the water that was formed in the reactor R-04 and must be removed. The gas stream can be sold to an industry that processes gas phase hydrocarbons, while the water removed can be sent to the effluent treatment plant. 4.2. Thermodynamic Model and Simulation Considerations The simulation of the STG+ process was developed in the software Aspen Plus ® version 7.2. In our simulation, we chose the GRAYSON model, because it was developed for systems consisting of hydrocarbons, such as carbon dioxide and hydrogen sulfide. This method should return good results for temperatures in the range of 60 °F to 800 °F and pressures up to 3000 psia (Aspentech Support Technology, 2001). Since our process contains hydrogen and all the temperatures of the streams are within this temperature range, we can use the GRAYSON model (Aspentech Support Technology, 2001). The first three reactors (R-01, R-02 and R-03) were modeled in Aspen Plus as RSTOIC reactors since only fractional conversions and stoichiometry were considered for them. The last reactor (R-04) was modeled as an RYIELD reactor. In this model, the input data that is required consists of the outlet temperature and pressure of the reactor, as well as the yield values for the components that are products of the reaction process. 4.3. Assumptions adopted in the simulation Natural gas feed consists only of methane; We used only flash drums to perform the separation of the components after the reactions. The gasoline yields only consist of paraffins, olefins, aromatics and cyclic hydrocarbons from C2 to C11. Fractional conversions and stoichiometry are only considered for the first three reactors and no kinetic parameters for the reaction processes and catalyst deactivation are considered due to lack of data. Even though the STG+ process is well known for the loop which defines the efficiency of the process, due to lack of data on fractional conversions for C2-C11 compounds, we restricted our simulation till gasoline production and planned to sell our product (Gasoline and Natural Gas) to the other parties who are in charge of any post treatment required. Since we are not including the durene/Isodurene in our output, the Gasoline treatment reactor is not considered. 5.0. Economic Evaluation In order to evaluate the economics of the project, a cash flow analysis is made based on the following considerations: Our business model consider buying treated natural gas to be used as both feedstock and fuel gas (we dont pay royalties because we are not producing it), paying for electricity consumption; and revenues come from gasoline and natural gas sales. Two years for construction and 20 years of operations. 340 days of production per year. Analysis in constant American dollars of January 2017, exchange rate of 1.30 CAD to USD. Annual non-fuel operating and maintenance cost equal to 3.6% (Haro P. et al ,2013) of total capital expenditures. Corporate income tax rate equal to 28%. Electricity consumption, fuel gas required, flow rates (feed and products) from the simulation model. Current prices for gasoline, natural gas and electricity in Alberta, taken from Alberta Energy websites. Capital Cost Allowance (CCA) with a half year rule is considered for tax calculation purpose according to Alberta legislation. Discount rate 10%. Capital expenditure (CAPEX) for syngas generation is estimated using figures for a known plant (Yang Ogden, 2005) and the following equation to take into account the different capacities. . (5) Where, Cx = capital cost for a plant of size x (Sx), Cb = capital cost of the known plant of size b (Sb). CAPEX related to the STG+ process itself is estimated based on the ratio given by Primus Green Energy (company proprietary of the STG+ technology) that syngas generation typically represents 60% of total capital cost for commercial-scale plant and the STG+ process itself represents the other 40%. Two scales are considered: 10 MMSCFD of natural gas in the feed for comparison purpose with the previous years group and 62.5 MMSCFD of natural gas in the feed to evaluate the influence of the scale on the economic indicators. The economic indicators of the project are summarized in the following table: Feed Gas Flow rates (MMSCFD) 10 62.5 Net Present Value NPV @10% (million $) 14.66 371.86 Internal Rate of Return IRR 12.12% 22.87% Profit to Investment Ratio PIR 0.14 0.97 Breakeven price for Gasoline (CAD/L) 0.91 0.62 Table 1: Economic Indicators for project evaluation (Detail calculation in Appendix) Finally, a sensitivity analysis is made to see the influence of different variables: natural gas price, electricity price, gasoline price and capital cost on the NPV of the project. For these, all variables are changed +10% and -10% and the NPV are calculated. Results shown in the fig. 2 correspond to the case with 62.5 MMSCFD in the feed. However, it is the same trend in both cases: Figure 2: Sensitivity Analysis for case 62.5 MMSCFD It can be concluded that the project is economically feasible and the variable that impact the most the economics of the project is the gasoline price. 6.0. Recommendations We recommend considering the fractional conversions for C2-C11 compounds in reactor 1 to have a better picture of STG+ with its close loop process. A thorough composition analysis for gasoline in the fourth reactor gives more realistic results. There is much scope to extend our work by adding gasoline treatment and distillation column (instead of flash drum for more efficient separation) with proper chemical reactions and stoichiometric fractional conversions and kinetics to improve the market value of our product. There is possibility for considering more components in the feed gas till C5-C6. In our model, due to lack of data, we focused on chemical reactions and stoichiometric fractional conversions. There is scope for more efficient designing by working on catalyst cycle life. 7.0. Conclusion The 21st century is witnessing the establishment of a new global business based on natural gas processing. As a consequence, the gas-to-liquids (GTL) industry is becoming increasingly important as it is getting more difficult to find and extract new oil reserves as well as the presence of more environmental restraints. This is why we decided to apply the new STG+ process technology in our project to demonstrate its efficiency in the conversion of methane to gasoline. As previously stated, we decided to differ from the previous group process, mainly because its technology is old and their product is diesel as opposed to STG+ process which is a novel technology and its product being gasoline, which is more demanded in Canada. We chose to do the simulation of a small scale GTL plant that processes 10 MMSCFD of methane, producing 672 bbld, which resulted in an economically viable process. The economic indicators showed that, by increasing the production of gasoline, the profit would incr ease significantly (proven with the case 0f 62.5 MMSCFD). In conclusion, STG+ might be indeed successful and profitable in Alberta if there is a reliable source of natural gas and good market conditions. 8.0. References Alberta energy website.http://www.energy.alberta.ca/NaturalGas/1316.asp. Accessed on March 16th, 2017. Alberta energy website.http://www.energy.alberta.ca/Electricity/679.asp. Accessed on March 16th, 2017. Aspentech Support Technology, Inc.; Aspen Physical Property System 11.1; Cambridge, MA, September 2001. Choudhary V. R., Rajput A. M., Prabhakar B; Low temperature oxidative conversion of methane to syngas over NiO-CaO catalyst; Chemical Engineering Division; National Chemical Laboratory, India, May 1992. Haro P, Trippe F, Stahl R, Henrich E. Bio-syngas to gasoline and olefins via DME: A comprehensive Techno-economic assessment; Apple Energy; 2013; volume 108; page no.: 54-65. Heng H.C., Idrus. S; The future of gas to liquids as a gas monetization option; Journal of Natural Gas Chemistry 13, 2004; pages 63-70. http://www.albertagasprices.com/index.aspx?fuel=C . Accessed on March 16th, 2017. Kasaie M., Sohrabi M.; Kinetic Study on Methanol Dehydration to Dimethyl Ether Applying Clinoptilolite Zeolite as the Reaction Catalyst; Chemical Engineering Department, Amirkabir University of Technology, Tehran, Iran, January 2010. Keil, Frerich J.; Methanol-to-hydrocarbons: process technology; Department of Chemical Engineering, Technical University of Hamburg-Harburg, Hamburg, Germany, July 1998; page 49. Larminie, James, Dicks, Andrew; Fuel Cell Systems Explained; West Sussex, U.K.: John Wiley Sons; 2000. Lebarbier V. M., Dagle R. A., Kovarik L., Adarme J. A. L., King D. L., Palo D. R.; Synthesis of methanol and dimethyl ether from syngas over Pd/ZnO/Al2O3 catalysts; Richland, USA, June 2012. Mbodji M., Commenge J.M., Falk L., Di Marco, Rossignol F., Prost L., Valentin S., Joly R., Del-Gallo P. Steam methane reforming reaction process intensification by using a milli structured reactor: Experimental setup and model validation for global kinetic reaction rate estimation, Chemical Engineering Journal, vol. 207-208, pages 871-884. Primus Green Energy website (http://primusge.wpengine.com/press-room/white-papers/), Accessed in March 2017. Shell Global Website (http://www.shell.com/energy-and-innovation/natural-gas/gas-to-liquids.htm), Accessed March 05, 2017. Wood, David A., Nwaoha C., Towler, Brian F; Gas-to-liquids (GTL): A review of an industry offering several routes for monetizing natural gas; Journal of Natural Gas Science and Engineering, Volume 9, November 2012. Yang, Christopher; Ogden, Joan M. (2005).Analyzing Natural Gas Based Hydrogen Infrastructure Optimizing Transitions from Distributed to Centralized H2 Production; Institute of Transportation Studies; UC Davis. 9.0. Appendix Component in Aspen Plus ® Component name Formula Mass yield METHANE Methane CH4 - METHANOL Methanol CH4O - CO Carbon monoxide CO - CO2 Carbon dioxide CO2 - H2O Water H2O - ETHER Dimethyl ether C2H6O - H2 Hydrogen H2 - OCTANE n-Octane C8H18 3.582 HEXANE n-Hexane C6H14 2.702 HEPTANE n-Heptane C7H16 3.142 NONANE n-Nonane C9H20 4.022 DECANE n-Decane C10H22 4.462 N-C11 n-Undecane C11H24 24.602 N-C5 n-Pentane C5H12 36.078 OXYGEN Oxygen O2 47.549 ETHANE Ethane C2H6 4.901 PROPANE Propane C3H8 45.691 N-BUTANE n-Butane C4H10 69.321 ISOC4 Isobutane C4H10 101.615 ISOC5 2-Methyl-butane C5H12 75.269 ISOC6 2-Methyl-pentane C6H14 34.921 ISOC7 2,2-Dimethylpentane C7H16 3.137 ISOC8 2,2-Dimethylhexane C8H18 1.690 ISOC9 2-Methyloctane C9H20 0.491 ISOC10 2-Methylnonane C10H22 37.092 AROMC6 Benzene C6H6 4.024 AROMC7 o-Xylene C8H1

Civil War - Gettysburg :: essays research papers

For five days Jackson had looked on Washington spread before him with the Dome of the Capitol in sight from his headquarters on the Georgetown Pike near 7th Street. Lee having recovered sufficiently from his wounds had resumed command of the army but had been summoned to Richmond by President Davis following overtures from ( Vice ) President Johnson to discuss common grounds for a peaceful settlement to the War. Lincoln left the Capital for Canada, reluctantly, following pressure from Cabinet to avoid possible capture by the advancing Confederates who seemed unstoppable as the Union forces in and around Washington disintegrated into a disorderly rabble. Following his heroic retreat from Gettysburg Howard had been promoted to Lieutenant-General and assumed command of the defenses of Washington superseding Major-General S.P.Heintzelman who had very little combat experience. Howard had about 55,000 men but very little control and desertions were whittling this force away hourly. The Federal army was totally demoralized and soldiers were going home as if it was all over, sensing the end was near. Grant had, after eventually capturing Vicksburg on the 4th July been ordered to evacuate and return control to the Confederates under Pemberton. This would be accomplished by the 12th and an uneasy peace would settle across the Western theatre as Lieutenant-General ( Old Pete) Longstreet entrained to take command of all the South’s western forces. Jackson chafed... aware that the Union forces were a spent force and there for the taking, his spies reported that the defenders had shrunk to 35,000 and if they waited for another couple of weeks Washington would be a ghost town. France had broken with England and recognized the independence of the Confederacy and England was expected to follow suit very soon. In Richmond McClellan was leading the Union delegation and was pursuing a course of peace on reasonable terms. Basically, it had settled down to where the borderlines would be drawn. Davis was prepared to concede what was now West Virginia but wanted the Indian and Arizona territories. Robert E.Lee had been appointed commander of all the Confederate Forces and given a free hand in appointments and troop dispositions. Lincoln was under house arrest in Niagara, not because the British had anything against him but for his own safety as his popularity was zero and the British government didn’t want any untoward incident for which they could be blamed. Jackson had