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DEPARTMENT OF CHEMICAL ENGINEERING JAYPEE UNIVERSITY OF ENGINEERING & TECHNOLOGY, A-B ROAD, RAGHOGARH, DT. GUNA 473226, M.P., INDIA PRODUCTION OF PHENOL FROM CHLOROBENZENE

Shikhar Prakash (101446)Sumit Verma (101449)

1Production of Phenol from Chlorobenzene1 Natural occurrences Natural occurrences: During fractionation of coal tar, carbonic oil fraction is separated containing 30-35wt% phenolic components and liquid byproducts from gasification process.Applications: Used as an disinfectant in household cleaners and in mouthwash, used forsynthesis of dyes, aspirin (C9H8O4). Used for making picric acid , Used in the manufacturing of Bisphenol - APhenol is also used to produce Aniline

Product specifications & standardsPhenol is classified as a Class B poison.The US Pharmacopeia (USP) specifications for phenol include: Purity is to be no less than 98 wt%.Clear solubility of 1 part of phenol in 15 parts of water.A congealing temperature to be not lower than 39C.A content of non volatiles is no more than 0.05 wt%.

Phenol demand forecast in IndiaGraph 1: Production / Import of phenol in metric ton per year.Plant capacity on demand - supply basis (for 2014)Demand: 240,000 TPAProduction: 80,000 TPAImport: 160,000 TPA

Plant Capacity: 200,000 TPA (To meet the demand).S. No.SpecificationUnitsProcessesCumene OxidationToluene Benzoic AcidSulpho-nationChloro BenzeneRaschingFeed Stocks1.TolueneT/T-1.45---2.BenzeneT/T0.67-0.951.010.9253.ChlorineT/T---1.04-4.PropyleneT/T0.38----Utilities(Consumption per tonne of phenol)SteamTonne3.59.02.79.016.5Cooling waterm335658025050Process waterm30.02-6.51.0-ElectricityKWh3506501003900350Fuel Oil106 KJ4.53.5155.514Inert gas(High Pressure)SCF8040---Natural GasBTU--2100100004000The most widely accepted technology for producing phenol is cumene oxidation process because of better economics due to by-product acetone. If one wants to avoid acetone, the choice will be toluene oxidation process.

Selected processPhenol from chlorobenzeneThere aretwo reactions to convert chlorobenzene to phenol using chlorination route:CausticizationC6H5 Cl+ NaOH C6H5ONa NaOH is in aqueous media (Operating conditions: 425C and 350 atm, Exothermic reaction)Hydrolysis C6H5ONa + HCl (aq) C6H5 Cl + NaCl (aq) (Operating conditions: 1 atm & 60 C)

Fig1. PFD for production of Phenol from Chlorobenzene

Material BalancePhenol production with a purity of 99% = 2,00,000 TPA.All calculations are done on per hour operation.Working days in a year = 330 days.Molecular weight of phenol = 94.Per hour production = 25252.53 kg/hr. = 268.644 kg mol/hr.

Various assumptions and values taken from literature: Overall material balanceComponentIn (Kg/h)Out (Kg/h)Chlorobenzene32113.1431605.668Sodium hydroxide14263.8103423.303Diphenyl oxide2575.2772575.277Phenol--------25507.566Sodium chloride--------15839.168Total48952.23048950.982Energy balance H 298 = -114.567 KJ/mol

H C6H5Cl = 285.297(230.0238) (373-303) = 17718836.42 J/mol

H NaOH = 356.622 (86.0937) (573-303) = 3243363.955 J/mol

HC6H5OH =271.033 (239.334)(353-303) = 3243363.955 J/mol

H NaCl = 271.033(84.4090) (353-303) = 1143881.74 J/mol

Heat of reaction = Heat of product Heat of reactant+ H 298

Heat of reaction = -21735942.74 J/mol

Production of Phenol from Chlorobenzene11Heat balance across Heat balance across heat exchangerheat exchanger inlet outlet reactor inlet Tref = 303 K Tref = 303K,Tin = 313 K T= 573KQNaOH = 310595.5465 J Q NaOH = 8342126.471 JQC6H5Cl = 5449157.38 J QC6H5Cl = 14019901.52 JQ C12H10O = 45211.0613 J QC12H10O = 1358477.399 J

Heat balance reactor outletHeat balance neutralizer in

Tref = 303 K, T = 698 KT ref = 303K, T= 333 KQHCl = 19671615.81 JQHCl = 309069.2717 JQ C6H5Cl = 1190158.848 JQNaOH = 223550.9719 J QNaOH =2920034.506 JQ C12H10O = 136762.8128 JQ C12H10O = 2147280.632 J

Production of Phenol from Chlorobenzene12QC6H5OH = 3116121.024 JQNaCl = 115353535.308 JQC6H5Cl = 111834.3687 JQNaOH = 372452.6559 JQ C12H10O = 229770.867 JEnergy balance across distillation columnAssumptions:Temperature of distillate = 460 KBoiling point of Diphenyl oxide = 531.46 KBoiling point of phenol =455 KFeed enters at =353 K

Production of Phenol from Chlorobenzene13

Production of Phenol from Chlorobenzene14

Utility required in reactor

Heat of reaction = -21735942.74 J/molCp of water = -75.327 J/mol KH = n*Cp*dT -21735942.74 = n*(-75.327)*(40)n = 7213.861 molesWeight of water required = 7213.861*18 = 129849.5126 g/hr

Process & mechanical design of neutralizing tank C6H5ONa + HCl C6H5Cl + NaCl EQUIPMENT - Cylindrical vessel with a drain valve and a turbine agitator

Total weight of the reacting mass = 48950.587 kg/h Average density at 60oC= 1.4006 kg/litre Total volume of reacting mass=

Let residence time (T) = 2 hours

Vo= mav/dav =34.949 m3/hr

T = V / Vo

V = 69.898 m3

Where V = Volume of reactor

L/D = 1.25

D= 4.14 m, H=5.18 m

Mechanical design The maximum pressure in the tank is 14.70 psi (1 atm)

ts=[{(14.70 x 4.14)/(2 x 20000 x 0.8)}+0.005] x 2.54 =5.13 mm

Take shell thickness= 5mm

Design pressure is above 100 Kpa, ellipsoidal head would be an ideal choice

Major axis: Minor axis=2:1

Inside depth (B=A/2), A=D/2, B=D/4

B=1.035 cm

Volume V of the ellipsoidal head

V = (3.14 x 4.142 x 5.18/4) + (3.14 x 4.143/12) = 88.306 m3 Design of agitator

Let diameter of the agitator= 0.6 x DDa= 0.6 x 4.14= 2.484 m

Speed of the agitator=75 rpm = 1.2 rpsAverage Viscosity =3.6 cpAverage density of the slurry=1.1747 kg/lt

Calculating Reynolds Number Nre Nre = 112584.00

Calculating Froude number NfrNfr = n2 x Da/g = 1.252 x 2.484/9.81 = 0.3956

1 cm=1/30.8 ft

1 kg/lt= 62 lb/ft3

9.81 m/s2=32.17 ft/s2

Power=[(0.123)-0.0935 x 1.253 x (8.1710)5 x 1.4006 x 62]/32.17

Power=331.52 ft/lbf

Power=0.513 HP

Assuming frictional losses

Power= 1.5 HP

Torque in the shaft=2 x 550/2 n

Torque in the shaft= 140 ft/lbf

Distillation Column: Process designFeed components:Phenol 271.0333 kmol/hrDiphenyl oxide 15.13 kmol/hrTotal feed = 286.163 kmol/hrDistillate components:Phenol 265.64 kmol/hrDiphenyl oxide 2.683 kmol/hrTotal = 268.323 kmol/hrBottom components:Phenol 5.393 kmol/hrDiphenyl oxide 12.447 kmol/hrTotal = 17.84 kmol/hrComponentFeed, xfDistillate, xdBottom, xbPhenol0.9470.990.302Diphenyl oxide0.0530.0090.698Using Antoine Equation, we find vapor pressure:

P = A-(B/ (T+C))T in Kelvin, Pressure in bar.

ComponentABCPhenol4.246881509.677-98.949Diphenyl oxide4.136781800.415-95.324Top temp at 123CBottom temp at 150CPhenol0.145990.3948Diphenyl oxide0.014090.04487Calculated Vapour Pressure in bar: Heavy key component Diphenyl oxideLight key component Phenol

Relative volatility calculation : top = 10.36 bottom = 8.798

avg = ( top* bottom)0.5= (10.36*8.798)0.5= 9.5475.

Fenske equation :

Nm = log [(XLK/ XHK)d*( XHK/ XLK)b] / log avg

(XHK) d = 0.302(XLK) d = 0.698(XHK) b = 0.990(XLK) b = 0.009Nm = log [(0.698/ 0.302)*( 0.990/ 0.009)] / log 9.5475 = 2.52 Nm 3Underwoods Method:

(i*xif)/ (i-) = 1-q

We get, =1.4960 (i*xif)/(i-) = Rm+1We get, Rm = 0.138Gillilands correlation:

On solving, we get N = 8.983 9Assuming, tray efficiency = 0.5Therefore, actual no. of trays = 9/0.5 = 18

Tower diameter required at top:Distillation: Vacuum distillation at 100mm Hg

Molar flow rate of vapor & liquid at top in enriching section L = R*D = 0.2074*268.323 = 55.650 kmol/hrV = (R+1)*D = 1.2074*268.323 = 323.973 kmol/hrL/V = 55.650/323.973 = 0.172Mavg = xiMi = 94.7621

Assuming tray spacing = 0.6 mFrom Figure 11.27 of R.K Sinnott (Coulson & Richardsons) page-568K1 = 0.08uf = flooding velocity

uf = 3.6 m/sec

Now, Actual velocity = 0.85 * uf = 2.88 m/secVolumetric flow rate of vapor at the top, Qv = (V+Mavg) / v = 2.168 m3/sAn = net area required at the topAn = Qv/V = 0.753 m2Down comer area, Ad = 0.12*Ac (Reference: Sinnott)An = Ac AdOn solving, Ac = 0.856 m2Di = 0.98 m

Tower diameter required at bottom:Similar procedure was followed to calculate bottom diameter:Bottom diameter comes out to be 1.02 m

Height of Distillation Column:Height of column, Hc = no. of trays * tray spacingActual no. of plates = 18Tray spacing = 0.6 mSo, height of column = 18 * 0.6 =10.8 m

Mechanical designCalculation of Thickness:Allowable design stress, f= 1.18MN/m2 Welding joint efficiency factor, J=0.85

t = [PDi/ (2*f*J-P)]

= [(13.33*103*1.02)/ (2*1.18x106*0.85)-(13.33*103)] = 0.06 mEconomic Analysis Costing of distillation columnThickness of shell = 0.06 mWeight of vessel = = x 10.8 x 0.06 x 7850 = 16292.003 Kg Where r is the internal radius of distillation column, L is the length of column, t is the thickness of shell.Density of carbon steel = 7850 Kg/m3Weight of head, skirt = 10% weight of vessel.Total weight of column without tray = 1.1 x 16292.003 = 17921.23 Kg

Production of Phenol from Chlorobenzene31Production of Phen