Phthalic Anhydride is an important aromatic di-carboxylic acid anhydride. It is an ortho-derivative of phthalic acid. The raw materials are air and o-xylene. The o-xylene feed, which may be considered pure and at 0.75 atm, is pumped to 3 atm and then vaporized in a fired heater. Air, which may be assumed to contain only O2 & N2 is compressed to 3atm and heated in a heat exchanger. The hot air and vaporized o-xylene are mixed and sent to a packed bed reactor. Packed bed reactor is multitubular reactor filled with supported V2O5. 100% of o-xylene is reacted in this reactor. In the selectivity data table we observe the fractional conversion of o-xylene into Phthalic anhydride and maleic anhydride are 0.7 and 0.1 at 360◦ C respectively. Also, the selectivity for complete combustion reaction is 0.2. Therefore, the reactor is maintained at 355-365◦ C. Also, the reactor is maintained at 3 atm and a contact time within the reactor is about 0.1-0.4 seconds. Since all the three reactions taking place in a reactor are highly exothermic, the temperature is controlled around 355-365◦ C using Molten salt (High Heat Transfer Salt). The reactor effluent, which is at 2 atm enters a complex series of devices known as switch condensers. The feed to switch condensers may be no higher than 180◦C, hence reactor effluent must be cooled. The net result of switch condensers is that all light gases and water leave the top stream of reactor with small amounts of both anhydrides (PAN & MAN), while large amounts of PAN and MAN leave in stream which is feed to distillation column. The stream containing large amounts of PAN is fed to distillation column which results in formation of bottom product of quality 98% PAN.
[...] A location should be chosen, if possible which has several competitions will help to maintain low rates and give better service. Often times, a location is selected outside the city in order to have a rail road siding available and thus eliminate trucking costs to freight years from excessive costs of transportation. There will be more long distance water transportation used in the future to reduce the cost of freight years from excessive costs of transportation. There will be long-distance water transportation used in the future to reduce the cost of freight, with the spread between production cost and sales cost constantly narrowing. [...]
[...] It includes everything from the original of the building to the location and movement of a small component. It is an integral part of: PRODUCTION PLANNING: It allows, promotes and aids the creation of utility. MAINTENANCE: It affects the amount, difficulty and time required for it. MATERIAL HANDLING: This is necessitated by the design & layout of the plant. ORGANIZATION: Physical layout often determines areas of authority, spheres of personnel influence. Obviously machines, equipment, materials, employees, fixtures and all the necessary facilities for engaging in an activity must be given a place of work. [...]
[...] Where it is possible to pump a single material to an elevation so that subsequent handling can be accomplished by gravity into intermediate reaction storage units. Equipment layout: In making layout, ample space should be assigned to each piece of equipment accessibility is an important factor for maintenance. Unless a process is well seasoned, it is not always possible to predict just how its various units may have to be changed in order to be in harmony with each other. [...]
[...] Using Antonie's equation, Vapor pressure of MAN at 333 K K are 3.536 mm Hg mm Hg. Vapor pressure of PAN at 333 K K are 0.153 mm Hg mm Hg. atop = 3.536 / 0.153 = 23.11 ; a bottom = 186.2 / 17.36 = 10.73 a=sqrt( atop* a bottom) =sqrt( 23.11 * 10.73 ) = 15.75 y = 15.75 14.75 is equilibrium relation. Let us assume that boiling point of feed varies linearly with composition Boiling point of PAN and MAN are 560 K and 473 K For feed composition, Boiling point of feed 55.888 *560+ 7.84 55.888 + 7.84 ) = 549.3 K Specific enthalpy of feed if feed is saturated liquid = cal/mol = 78492.5 kJ/kmol Specific enthalpy of feed = 7972.15 cal/mol = 33369.8 kJ/kmol Normal Heats of vaporization PAN 11850 cal/mol = 49601.73 kJ/kmol MAN 5850 cal/mol = 24486.93 kJ/kmol Let us assume that latent heat of vaporization of feed varies linearly with composition λ feed = ( 55.888 * 49601.73 + 7.84 * 24486.93 55.888 + 7.84 ) = 46511.66 kJ/kmol Specific enthalpy of feed if feed is saturated vapor = Specific enthalpy of saturated liquid + Latent heat of vaporization of feed = 78492.5 + 46511.66 = 125004.2 kJ/kmol (Hv - hF hL ) = ( 125004.2 - 33369.8 125004.2 - 78492.5 ) = 1.97 Assume that constant Molar overflow rate is prevailing. [...]
[...] = A + B = Rs Selling price for 1 ton of phthalic anhydride = Rs So, for production of 60000 tons, the total selling price = Rs Therefore, gross profit = S.P. C.P. = Rs Income tax = 38% of G.P. = Rs Therefore, net profit = Rs Capital earning rate = net profit / total investment * 100 = 42.997 Capital payout time = total capital investment / property earnings + Depreciation = 2.323 years Rate of returns = Net profit * 100 / total capital investment = plant location Plant Location and Site Selection: The major requirements for an Ethylene Glycol plant are ethylene oxide and water. [...]
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