Question

Terephthalic acid (TPA) is synthesized from -xylene (PX) in the process C8H10 +302 – C8H6O4 +2H2O shown below. A fresh feed of pure liquid PX combines with a recycle stream containing PX and a solution (S) of a catalyst (a cobalt salt) in a solvent (methanol). The combined stream, which contains S and PX in a 3:1 mass ratio, is fed to a reactor in which 90% of the PX is converted to TPA. A stream of air at 25 °C and 6.0 atm absolute is also fed to the reactor. The air bubbles through the liquid and the reaction given above takes place under the influence of the catalyst. A liquid stream containing unreacted PX, dissolved TPA, and all the S that entered the reactor goes to a separator in which solid TPA crystals are formed and filtered out of the solution. The filtrate, which contains all the S and PX leaving the reactor, is the recycle stream. A gas stream containing unreacted oxygen, nitrogen, and the water formed in the reaction leaves the reactor at 105 °C and 5.5 atm absolute and goes through a condenser in which essentially all the water is condensed. The uncondensed gas contains 4.0 mole% O2. Taking 100 kmol TPA produced/h as a basis of calculation, draw and label a flowchart for the process. What is the required fresh feed rate (kmol PX/h)? What are the volumetric flow rates (m³/h) of the air fed to the reactor, the gas leaving the reactor, and the liquid water leaving the condenser? Assume ideal gas behavior for the two gas streams. What is the mass flow rate (kg/h) of the recycle stream? Mwt of (TPA) =166, Mwt of (PX) =106.

Q21:- PX -p-xylene S-solution TPA = terephthalic acid Off ASOS 4 mol % O2. 96% NZ Oy. N. Hov) 105 Ć. 5.5 atm HO) CONDENSER Air © 25C. 6.0 atm CH, 30, -C,H,O, +2H5O PXCI) Reactor food 3 kg S/kg PX TE PX, TPA, S SEPARATOR TPAD Recycle (I). PX, S Terephthalic acid (TPA) is synthesized from -xylene (PX) in the process C.H.+30 C.H.O. +2H2O shown below. A fresh feed of pure liquid PX combines with a recycle stream containing PX and a solution (S) of a catalyst (a cobalt salt) in a solvent (methanol). The combined stream, which contains and PX in a 3:1 mass ratio, is fed to a reactor in which 90% of the PX is converted to TPA. A stream of air at 25 °C and 6.0 atm absolute is also fed to the reactor. The air bubbles through the liquid and the reaction given above takes place under the influence of the catalyst. A liquid stream containing unreacted PX, dissolved TPA, and all the Sthat entered the reactor goes to a separator in which solid TPA crystals are formed and filtered out of the solution. The filtrate, which contains all the S and PX leaving the reactor, is the recycle stream. A gas stream containing unreacted oxygen, nitrogen, and the water formed in the reaction leaves the reactor at 105 °C and 5.5 atm absolute and goes through a condenser in which essentially all the water is condensed. The uncondensed gas contains 4.0 mole% 02. Taking 100 kmol TPA produced/h as a basis of calculation, draw and label a flowchart for the process. What is the required fresh feed rate (kmol PX/h)? What are the volumetric flow rates (m²/h) of the air fed to the reactor, the gas leaving the reactor, and the liquid water leaving the condenser? Assume ideal gas behavior for the two gas streams. What is the mass flow rate (kg/h) of the recycle stream? Mwt of (TPA) =166, Mwt of (PX) =106.

Answer 1

P 1 402 N₂ Condenser X a Nz pH₂O H20 Air no Reactor PX 8 3 seperator PX → TPA R PX, 8 Cohio + 30, 6 G H o ou + 2H₂O Single pass conversion of PX = 90% to produce 100 kinol TPA, PX at Reactol 80 hr inlet : 111.11 Kuel 111.11% 106 Islar 100 0.9 hr 11777.78 kg/hr 11777.78 X 3 = 35333.33 Kay go I at Reactor illa H₂O produced 2 X 100 200 kus) hr 200818 kg/hr 3600 ks/hr O consumed a 3 x 1000 200 krol ho PX - Unneacted 111.11 - 100 11.ll knel/hr Dt will be recycled back to Reactor do fresh px fed to Reactor 100 kmol/ur

let no moles of of Air enter the reactor 80 O₂ Balance in out consumed LO 0.21 m. 0.ou p - 300 > 0 > 0.21n, 0.0-4 P : 300 300 . Ne balance . 0.79 ni = 0.96 p

ne 1394.11 kerol/ Pz 1147.24 kool/hr vol. flow of Air fed a HRT 1394.11 X 89144 298 X10', 5682.8 me 681012 X 165 hr moles of vap. at olla 1194.1) 300+800 12g4ill Kustur vol. flow a ner 1894.11 X 8.314 x 378_X103, 78299.62 mgo SorX 1.013X 105