ENERGY BALANCE AROUND LIGHT END COLUMN

in distillation column energy balance is made around Reboiler and Condenser

4.5.2: Balance around Reboiler

Inlet Temp   of cold fluid = t₁ =    76  ^oC

Outlet Temp   of cold fluid= t₂ =     90  ^oC

Inlet Temp of hot fluid    = T₁ =     125^oC

Outlet Temp of hot fluid = T₂ =     125^oC

Latent heat of MEG at 76 ^oC  = λ = 61010.488  KJ/kgmole

Molar flow rate of vapours leaving the Reboiler=0.2338446 kgmole/sec

Enthalpy of feed entering the Reboiler= 42513*3.48*(350-298)= 7693152

Enthalpy of vapours leaving the Reboiler = Vm * λ = 0.2338446 * 61010.488

= 14266973.32 J/sec = 5136113.95 KJ/hr

Latent Heat of  Steam at 125 ^oC =2187 KJ/Kg

Mass Flow rate of the Steam = 23484.72 kg/hr

Enthalpy of steam entering  the Reboiler= 5136113.95 KJ/hr

Enthalpy of feed entering the Reboiler= 42513*3.48*(350-298)= 7693152

Enthalpy of bottom product leaving the Reboiler =7695132

Total heat in=5136113.95+7693152=12829265 KJ/hr

Total heat out=12829265 KJ/hr

  

4.5.2: Balance around Condenser

Inlet temperature of the process (condensing) stream= T₁ =T =72 ^oC

Outlet temperature of the process stream= T₂ =T=161.6 ^oF =72 ^oC

Inlet temperature of the water = t₁  = 77 ^oF=25 ^oC

Outlet temperature of the water = t₂ = 113^oF=45 ^oC

Mass flow rate of the process stream = m = 33322 lb/hr= 15128 kg/hr

 of   Process Stream  = 1001 B.T.U / lb = 2327.65553 K J / Kg

 Enthalpy of   process stream entering Q = m * = 15128 * 2327.65553

                                                    = 3.52127 *10⁷  KJ/ hr

C_p of cooling water  =1 B.T.U/ lb. hr = 4.187 KJ/kg k

Mass flow rate of cooling water=m = 420310.55 Kg /hr

Enthalpy of water leaving       =420310.55 * (4.18738 * (45-25))

                                             = 3.52127 *10⁷   KJ/ hr