What is the full design (Chemical mechanical-thermal design) of the scrubber (ty

Question

What is the full design (Chemical mechanical-thermal design) of the scrubber (type packed column / ceramic/size 51mm) which used in the production of acetone via IPA dehydrogenation given that I T-34 C, P-150 kpa H. = 393 kgmolh Acetone = (0.00 1x321 5) kgmolh T- 25°C P- 200 kpa HO = 279.095 kgmolh Scrubber H. = 393 kgmolh Acetone = 92.15 kgmolh H2O = 14.24 kgrnolh IPA = 2.96 kgmolh T=27 °C . P= 163 kDa H2O- 293.34 kgmol/h IPA = 2.96 kgmolh Acetone: 92.058 kgmolh T- 20 °C, P-163 kpa Compounds Input (kgh)Input (kgh) Vapor products Liquid products output (kg h) output (kg h Acetone IPA Water 5344.7 5.35 5339 36 5280.12 786 786 Total 5023.71 6564.6 10797.08 11588 11588.43 1) Identify the type of scrubber that used for this design and select the size of packing 2) Calculate the diameter and area 3) Number of overall gas transfer 4) Height of overall gas phase transfer 5) Pressure drop/flooding pressure drop 6) percentage of flooding,....., Calculate other thing that help the design for the column and packing

Explanation / Answer

SCRUBBER DESIGN (PACKED COLUMN) Packing type = Intallox Saddles Packing size = 51 mm Packing MOC = PP Gas pr. Drop / m bed = 15 mmWC / m packing height = 147.1 (N/m2)/m Total packing height = 6 m (including all packed beds) Gas / Vapour Properties Gas / Air flow rate = 5344.7 kg/h OR 0 m3/h = 1.4846 kg/s =     0 m3/s Gas pressure at entry = 1.9000 atm Gas temperature at entry = 25.00 oC = 298.00 oK Gas / Air mol weight = 58 Component to be scrubbed Component Name = Vapour Component flow rate = 5.35 Kg/h % comp. in air/gas = 6 % (v/v) Molecular weight of comp. = 56.5 Liquid / Scrubbing media Properties Scrubbing media = IPA Liquid flow rate, L = 177.6 kg/h = 0.0493 kg/s Liquid Density,    L = 786 kg/m3 Conversion : Liquid Viscosity, µL = 0.0035000 Ns/m2 3.5 Cp          = 0.00350000 Ns/m2 Packing factor, Fp = 21 m-1 Charac. Packing Factor,Cf = 33     Ref. Table 6.3, Characterstics of Random packings Conversion factor, J = 1.0 factor for adequate liquid distribution & irrigation across the bed Calculations TO CALCULATE COLUMN DIAMETER Since larger flow quantities are at the bottom for an absorber, the diameter will be chosen to accommodate the bottom conditions. To calculate Gas density Avg. molecular weight = 29.45 Kg / Kmol If gas flow rate is given in kg/h If gas flow rate is given in m3/h Gas in   = 0.050412186 Kmol/s Gas in = (m3/s) x     273 x pr. in atm x    1 kmol = mass / mol wt     T in kelvin 1.0 atm 22.4 = (kmol/s) x T in kelvin x 1.0 atm x 22.4                   273          pr. In atm      1 = 0 Kmol/s = 0.648759 m3/s = 0 Kg/s mass = mol wt x kmol Select vol. flow rate and mass flow rate from above, Selected mass flow rate = 0.277778 Kg/s Selected vol. Flow rate = 0.234499 m3/s Selected molar flow rate = 0.009432 Kmol/s Therefore, gas density = 1.1846 Kg/m3 (mass flow rate / vol. Flow rate) To find L', G' and Tower c/s area Assuming essentially complete absorbtion, Component removed = 0.0320 Kg/s (molar flow rate x % comp. x mol. Wt.) Liquid leaving = 0.0813 Kg/s (Inlet liquid flow rate + comp. Removed) L'      G 0.5 = 0.01136 G'     L Using   0.01136 as ordinate, Refer fig.6.34 using a gas pressure drop of 147.1 (N/m2)/m     G' 2 Cf µL0.1 J = 0.04 (from graph)     G (     L --      G) gc Therefore, G' = 0.04     G (    L --   G) gc 0.5     Cf µL0.1 J = 1.4084 Kg / m2.s Tower c/s area = 0.1972 m2 ( c/s area = mass flow rate / G' ) Tower diameter = 0.5011 m = 501.1 mm = 500 mm Corresponding c/s area = 0.1963 m2 TO ESTIMATE POWER REQUIREMENT Efficiency of fan / blower = 60 % assumed / given To calculate pressure drop Pressure drop for irrigated = 882.60 N/m2 (pressure drop per m packing x total ht. of packing) packing For dry packing, O/L Gas flow rate, G' = 1.2519 Kg / m2.s (Gas inlet flow rate - Component removed) / c/s area O/L Gas pressure = 191634.9 N/m2 (subtracting pressure drop across packing) Gas density,       G = gas mol wt.   x      273      x gas o/l pr. 22.41m3/Kmol    T in kelvin 101330 = 4.4910 Kg/m3 CD = 96.7     Ref. Table 6.3, Characterstics of Random packings Delta P = CD     G' 2    Z G   = 33.74 N/m2 Pressure drop for packing = 916.34 N/m2 (irrigated packing + dry packing) Pressure drop for internals = 25 mmWC (packing supports and liquid distributors) = 245.17 N/m2 Gas velocity = 7.5 m/s Inlet expansion & outlet = 1.5 x Velocity heads = 1.5 x (V2 / 2g) contraction losses = 42.19 N m / Kg = 49.97 N/m2 (divide by density) Total pressure drop = 1211.48 N/m2 (packing + internals + losses) Fan power output = pressure drop,N/m2 x (gas in - component removed) Kg/s O/L gas density, Kg/m3 = 66.31 N .m / s = 0.07 kW Power for fan motor = 0.11 kW (fan power output / motor efficiency) = 0.15 hp

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