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INDUSTRIAL ORGANIC C HEMISTRY – EXAM 21/02/2018 Consider a stream 𝐹̇ composed by methane (30%), n-hexane (20%), n-octane (30%) and n-decane (20%) which is treated with the following downstream process: The inlet stream comes to the process at 𝑇0 = 500 𝐾 and 𝑃0 = 4 𝑏𝑎𝑟, it exchanges heat in the second flash and then it is fed to the first flash, which is operated at 𝑃𝐹1 = 3 𝑏𝑎𝑟. Then the liquid stream 𝐿1̇ coming from the first flash is fed to the second flash, which is operated at 𝑃𝐹2 = 1 𝑏𝑎𝑟. Considering the following assumptions: • Negligible pressure drops in the whole process scheme. • The equilibrium conditions are reached in each flash. • Vapour can be treated as an ideal mixture of ideal gases. • Liquid can be treated as an ideal mixture with negligible Poynting correction. • 𝐶𝐻4 can be treated as an incondensable compound. Evaluate: 1. The state of the feed 𝐹̇ before entering in the second flash. 2. The temperature of the first flash, as well as its extent of vaporization and the composition of the liquid stream 𝐿1̇ considering that the molar fraction of methane in the vapour phase is 0.7 3. The temperature of the second flash and its extent of vaporization, considering that 𝑇𝐹2 is 5°𝐶 above the minimum allowable temperature for the flash operating conditions. 4. The temperature of the feed 𝐹̇ at the exit of the second flash (𝑇1). 5. The state of the feed 𝐹̇ entering in the first flash 6. The thermal duty 𝑄̇ of the first flash. Thermodynamic data log10(𝑃°(𝑇)) = 𝐴 − 𝐵 𝑇 + 𝐶 ; 𝑇 = [𝐾]; 𝑃°(𝑇) = [𝑏𝑎𝑟] 𝐴 𝐵 𝐶 𝐶𝐻4 − − − 𝐶6𝐻14 4.00266 1171.530 −48.784 𝐶8𝐻18 4.04867 1355.126 −63.633 𝐶10𝐻22 4.07857 1501.268 −78.670 𝐶𝑝𝐿 [𝐽 (𝑚𝑜𝑙 𝐾)⁄ ] 𝐶𝑝𝑉 [𝐽 (𝑚𝑜𝑙 𝐾)⁄ ] Δ𝐻𝑒𝑣(𝑇𝑁𝐵𝑃) [𝐽 𝑚𝑜𝑙⁄ ] 𝐶𝐻4 − 35.8 − 𝐶6𝐻14 195.6 143.3 31573 𝐶8𝐻18 255.7 175.9 41495 𝐶10𝐻22 313.3 233.1 51392