Mass and Energy Balance Essay

AbstractThe objective is to produce a proposal for a chemical process ready which willing be able to produce 550,000 tonne/year ammonium hydroxide using LPG as the raw material. Different processes where researched and hence fin onlyy one was picked, travel reforming. This was inflexible to be the most viable and salute effective process using the raw materials we had available. The report explains in detail how the process works and all aspects of how the typeset will work including the mass and energy balance crossways the plant.What is AmmoniaAmmonia (NH3) is a stable compound and is mapping as a starting material for the formulate of many important newton compounds and bed excessively be directly utilize as fertilisers. It is produced by reacting hydrogen and nitrogen. It is a colourless catalyst with a sharp odour. The boiling buck is -33.35oC and its freezing point is -77.7oC.1 C atomic number 18 must be interpreted when handling ammonia as hobo cause dee p ruin in the skin irritation in the eyes and nose and when inhaled bunghole cause coughing, sore throat and headache.2 There argon polar method actings for the manufacture of ammonia. The three main methods are steam clean clean reforming, partial oxidation and electrolysis. practise and UsesAmmonia is a widely used chemical in assorted types of industries. One of the main user of ammonia is the agricultural industries for fertilisers. Around 80% of ammonia produced is for fertilisers such as urea, ammonium sulphate and ammonium nitrate.3 It is to a fault used as a building block for nitrogen containing compounds the give care nitric acid (HNO3). It is also used in the fibres and plastics persistence for the doing of acrylonitrile, melamine etc., and manufacture of explosives. Ammonia is also used in peeing treatment such as pH control and also in combination with chlorine to purify industrial and municipal water supply supplies. slight commonly uses include as a refr igerant in abridgement and absorption systems, manufacture of household ammonia, in the food and beverage industry 4.Figure 1 Pie chart showing the uses of Ammonia.Market TrendsGlobally ammonia prices have been headed up due the large(p) demand of fertilisers that are indispensable in the crop return to obtain mettlesome yield6. The current change price of ammonia in Europe goes up to $600 per tonne7.Figure 2 Shows the global demand for Ammonia (D.a.NH3- Direct application of Ammonia) As we weed see from the chart the trend of ammonia demand globally is upward. It is verbalise that the global ammonia market is to generate revenues of approx. US$102 billion in 2019. As in that respect is continous letth in population in the ontogenesis countries the likely to cause demand for foodstuffs are to increase even pass on. As the amount of agricultural land declines, ammonia- base nitrogen fertilizers will continue to attain importance in the future.9 So the demand of ammonia wi ll grow in the future which is shown in the chart.ProcessesThere are many different processes involved in the ammonia production. The most common processes for ammonia are partial oxidation, steam reforming and electrolysis. From these 3 processes the best process route is then selected and that process would be most economical and that meetes the design brief. partial(p) oxidizationPartial oxidation involves the reception of oxygen with fuel to produce hydrogen. The sideline equations re redeem the partial oxidation of ethane, propane, butane and pentane. 10 C2H6 + O2 2CO + 3H2, C3H8 + 1.5O2 3CO + 4H2, C4H10 + 2O2 4CO + 5H2, C5H12 + 2.5O2 5CO+ 6H2There is no hire for the cracking of LPG as they are light hydro ampere-seconds and can be used in partial oxidation.11 See Partial Oxidation unravel sheet (Reference 1 Partial Oxidation Flow Sheet)Hazards and Environmental strikeThe main emission is carbon dioxide which is a greenhouse gas and Partial Oxidation process emits more ca rbon dioxide compared to go Methane Reforming. Carbon dioxide emissions can be reduced by recycling it and selling it to urea and nitro-phosphate plants.13 No ammonia should be present in the air but possibly because of faulty equipment and maintenance activities, some ammonia maybe let go ofd. Ammonia becomes explosive at the 16%-25% volume in air which could occur if there are any leakages in the ammonia storage facilities. It is also unhealthful by inhalation and pulmonary oedema can occur up to 48 hours after exposure and could be fatal.12 Nitrogen dioxide that is released is a harmful gas can be harmful when inhaled but can be avoided as can be detected because of the smell.The large amount of screw up water from this process is an early(a) problem but there is a river near the Milford Haven site. Also water pollution is a impact which may occur because of the suspended and dissolved impurities. It could also affect the aquatic life. Therefore the water must be treated i n a full three stage water treatment plant out front disposing it. 13 The disadvantage of partial oxidation is that the capital costs are taller for partial oxidation compared to any other process. It is estimated to be 100-120 one thousand million for an annual production of 7.7 million GJ while for SR it will only be 70 million.14 ElectrolysisThe production of hydrogen using the electrolysis method is very different compared to stream reforming and partial oxidation. Electrolysis produces hydrogen by dissever water into hydrogen and oxygen using volts of current to separate the hydrogen to one electrode and oxygen at the other in a cell. type O is the by-product in the process of producing ammonia which is valuable because it can be used in other chemical processes or sold to other companies for profit. In electrolysis there is no CO2 produced therefore there is no pollution.Standard electrolytic ammonia production energy consumption historically has been about 12 megawatt-ho ur. The fuel cost alone of making ammonia is $600 metric ton, and including capital and operating expenses that metric ton of ammonia cost about $800 to make. Compare electrolytic and using uses of innate(p) gas as raw material the economically, for the past 100 years the cost of natural gas has not been higher than $1 and the fuel cost for a metric ton of ammonia from natural gas has been $30-$40. Figure 3 Ammonia Manufacturing ProcessFigure 3 Ammonia Manufacturing ProcessSteam ReformingGas purificationSyngas of a mixture of hydrogen, carbon monoxide, carbon dioxide and water can be broken down in to individual components and further cleansed by purification. The syngas will enter a shift reformist, which breaks down the carbon monoxide in to hydrogen and carbon dioxide using steam (H2O). Carbon dioxide is ofttimes more environmentally friendly than CO and can either be released in to the atmosphere or used in other steam reforming processes in the future.DesulphurisationSulp hur is a problem when carrying out steam reforming as it acts as a poison for the catalysts involved. It is important that this is removed prior to the syngas submission the system. The process is carried out in the figurehead of a catalyst, which is usually plate. This nickel acts as an absorber for the sulphur, and so several catalyst-filled tubes within the system with a large internal surface area will allow the sulphur to learn to be disposed of suitably.The ProcessHydrocarbons usually contain sulphur which necessarily to be removed. The purification section is the first bed of the whole steam reforming process. Feed is passed through tubes containing zinc oxide. The sulphur in the feed reacts with the zinc oxide to produce zinc sulphide. This is to ensure that the feed travelling to the steam reformer does not poison the catalysts in this section in any way. The catalysts used in the steam reforming process are nickel-based. These are easily poisoned by sulphur species.T he purified feed is mixed with steam and then is passed to the primary reformer, which involves a nickel-based catalyst where the steam reforming process is carried out. Once the hydrocarbon is cleansed of sulphur, the reforming process can begin. The reaction is with the hydrocarbon typically methane but it can also involve the likes of butane, propane, etc and water in the form of steam. The reaction for methane (CH4) is shown below.CH4 + H2O 3H2 + COH = +251kJmol-1C3H8 + 6H2O 3CO2 + 10H2C2H6 + 4H2O 2CO2 + 7H2C4H10 + 8H2O 4CO2 + 7H2C5H12 + 10H2O 5CO2 + 16H2Reactions for other hydrocarbons, such as ethane (C2H6), propane (C3H8), butane (C4H10) and pentane (C5H12) are also shown, with their respective steam amounts required and the products gained. Rows of tubular reactors are contained in a furnace, which operates at mingled with 650 1000 degrees Celsius. The hydrocarbon feed enters the system at a very high pressure, typically 20 30 bar. The process is carried out in the pres ence of a nickel-based catalyst which is packed into cylindrical tubes through which the steam/hydrocarbon gas mixture is passed. The catalysts act as surface for which the hydrocarbon will absorb and the steam. (Reference 2 Steam Reforming Flow Sheet)JustificationSteam reforming is the most viable offer as we have all of the raw materials available within lento access, whereas if we were to use other processes, then we would have to source other materials e.g. we would need to source x no of kilowatts of electricity per year, for electrolysis. Mass BalanceCp determineEnergy BalanceMaterial apostrophizesSimple Plant CostUsing a base of around 410 per ton of ammonia, and getup at 550,000 tonnes, it would be assumed that the plant would produce 225,500,000 a year of ammonia. The Burrup plant in Australia was built at a cost of 457 million and produces some 800,000 tonnes a year of ammonia. Using the 2/3 power rule, as follows, will allow the costs of the new 550k p/a plant to be shown. C = Cref(S/Sref)2/3C = 457000000 * (550,000/800,000)2/3C = 355,984,702The output of the new plant is 225,500,000, but the plant costs 355,984,702 to build, so it would stimulate around a year and seven months for the plant to be profitable, based on an estimation without including the costs of the raw materials.Taylor MethodPay can TimeSustainabilityThe environment is constantly changing, whether by nature or by human led processes. Sustainability is about trying to manage this change through balancing social, economic and environmental needs, both locally and globally for present and future generations.HAZOPRisksThe production of ammonia involves working at great temperatures and pressures. As such, it is vital that the equipment used in the plant is designed to withstand these conditions to give out properly. The high temperatures and pressures involved in the production of ammonia can potentially put tremendous amounts of strain on the pipes and vessels used. The risks associated with this are * Explosions from sudden release of pressurised gases from ruptured vessels * Fragmentation from rupture of the pipes* Fire* Poisoning from exposure to leaked materials* Chemical or thermal burns, again from exposure to leaked materials Not only are these hazards life-threatening, they would also be very expensive to put right for the production company. These risks can be avoided by preparing the plant for the conditions that it is about to go through. It is more economically viable to run the steam reformer at as high a temperature and pressure as possible. Magnesium oxide-lined furnaces, MgO, has a melting point of around 2800 degrees Fahrenheit, making it ideal for lining the furnaces used in the production of hydrogen. Hydrogen itself will cause some materials to become brittle and at last break. Hydrogen features an active electron and thus will behave like a halogen, causing erosion in the metals that it comes into contact with.This can be avoided b y using high-purity stainless steel in the sections of the plant which will come into contact with the hydrogen. This steel must have a level best hardness of 80 HRB on the Rockwell Scale. Ammonia itself is also highly sulphurous to the pipes that it may be travelling through. For this reason, it is recommended that stainless steel is also used here, at a similar hardness of that shown above. Most ammonia plants use centrifugally cast high-alloy tubing to hold the nickel-base catalyst in the primary reformer furnace. The most commonly used is similar in composition to level 310 with 25% chromium and 20% nickel, balance iron. This has a carbon inwardness in the range of 0.35 0.45% for improved high-temperature creep and rupture stress. Thermal certificate of piping involves fire brick owing to the high temperatures involved.