30.15 The convective mass-transfer device shown in the figure (right column) is used to generate a gas stream containing a mixture of phosphorous oxychloride (POCI) vapor diluted in inert helium (He) gas. This gas mixture is sent to a diffusion fumace to serve as the primary dopant for the manufacture of silicon-based solar cells. In the present process, pure (100%) He gas at a volumetric flow rate of 110 cm-is enters the 2.0-cm inner diameter tube at 50 C and 1.0 atm. The length of the tube is 60cm. Liquid POCI, enters a reservoir that surrounds the porous ceramic tube. The liquid POCI, enters into the porous ceramic like a wick. At the inner surface of the tube, the POCI; liquid vaporizes, with its vapor pressure determined by the process temperature. The process is maintained at a constant temperature of 50 C by a controlled heater surrounding the POCI, reservoir. Therefore, the transfer of POCI; to the gas stream is limited by diffusion across the convective boundary layer on the inside of the tube. The process can be considered dilute. The diffusion coefficient of POCI; vapor (A) in He gas (B) is 0.37 cmls at 1.0 atm and 50C. The vapor pressure of POCIz is PA = 0.15 atm at 50 C. The kinematic viscosity of He gas at 1.0 atm and 50 C is 1.4 cm s. He + POCI, vapor (Cacul Makeup liquid POCI Porous ceramic tube innerd=2.0 cm L = 60 cm Heated liquid POCI, reservoir 50 C Helium (He) inlet gas 50 C, 1.0 atm V. = 110 cm/sec a. Propose a model in final algebraic form to predict the outlet concentration of POCI, vapor (CA.cut) from the tube. The model should contain the following process variables: gas-phase inlet concentration of A, CA,in; gas-phase outlet concentration of A, CA.cuti ke tube mass-transfer coefficient; L tube length; D, tube inner diameter; Voca gas velocity; C. equilibrium vapor concentration in the gas stream. b. What is the convective mass-transfer coefficient, ke, at an inlet He volumetric flow rate of 110 cm/s? c. What is the outlet mole fraction of POCI; vapor (VA,cut) at an inlet He volumetric flow rate of 110 cm/s? d. If the inlet volumetric flow rate remains fixed at 110 cm/s, but the diameter d is doubled, what is the new ke and y1.cut? What is the maximum possible outlet mole fraction of POCI; vapor for an infinitely long tube? e