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[anaghahr]

Hi,
I have following questions about adsorption processes:
1) Any idea of voidage in a bed packed with adsorbents like mesoporous Silica Gel or Zeolite 13X or Activated carbon? Alternatively if anyone can provide the particle density for each of the above materials, the bulk density values are given by the manufacturers. Using the two densities the voidage can be obtained isnt it? In my simulations i am assuming a voidage of 0.5 irrespective of the adsorbent material. Is this a good assumption to start with?

2) How is cyclic steady state (CSS) different from steady state process- does CSS also mean that input=output for each component of the system? Is there any rule of thumb to predict the no. of cycles required to achieve cyclic steady state in an industrial PSA or SMB unit. Is it related to the number of beds used in the system? I presume that the separation performance of PSA or SMB process that is reported in the experiment is when this CSS is achieved.

3) In simulation of the Adsorptive separation of CO2 from thermal power plant emitted flue gas which also has O2+N2+H2O+NOx+SOx, can the extended Langmuir isotherm be used to start with in the absence of any experimental multicomponent isotherm data? Is the condition of same monolayer capacity for all the components valid for this system, if different values are used then it violates the thermodynamic consistency of the isotherm but the molecular sizes are different to assume the same value for all. The components here will deviate from ideal behavior.

Anu