PRESSURIZATION AND BLOWDOWN OF ADSORPTION BEDS .2. EFFECT OF THE MOMENTUM AND EQUILIBRIUM RELATIONS ON ISOTHERMAL OPERATION

Pressurization and blowdown of adsorption beds with a binary mixture of inert and adsorbable gas are studied. For pressurization, the stoichiometric penetration distance for the feed is predicted using a simplified analysis. An equilibrium model is then developed involving material and momentum balance equations to describe the bed dynamics. The pressure drop is given by Ergun's or Darcy's equations, and adsorption equilibrium is described by linear or Langmuir isotherms. The effects of pressure drop equation, isotherm shape, adsorbent capacity, pressure ratio and feed composition on penetration distance, pressurization time and pressurization amount are assessed. For blowdown, the equilibrium model is used to evaluate the bed dynamics. Also, plateau concentrations for blowdown, estimated using a simplified analysis, are compared with predictions of the equilibrium model.