Lm. Sun et al., NUMERICAL STUDY ON COUPLED HEAT AND MASS TRANSFERS IN AN ADSORBER WITH EXTERNAL FLUID HEATING, Heat recovery systems & CHP, 15(1), 1995, pp. 19-29
Citations number
NO
Categorie Soggetti
Energy & Fuels","Engineering, Mechanical",Mechanics,Thermodynamics
This paper presents a numerical study of coupled heat and mass transfe
rs in an adsorber with external fluid heating. A one-dimensional model
incorporating both heat transfer and Ergun flow of the adsorbate insi
de the adsorber is developed. Numerical investigations are made for tw
o adsorbent-adsorbate pairs: zeolite 13X-water and 13X-ammonia, whose
operating pressures are considerably different. It is shown that, for
the 13X-water pair which has a low operating pressure and therefore a
low gas density, the dynamics of the adsorber can be significantly lim
ited by the mass transfer inside the adsorbent bed, when its dimension
is large. The poor mass transfer can lead to very large pressure vari
ations and small adsorbed or desorbed quantities, making the heat pump
process ineffective. Conversely, the zeolite-ammonia pair operates at
much higher pressures (several bars) and the corresponding pressure v
ariations in the bed are, in general, negligible. In this case, the li
mitation by mass transfer can be neglected and the uniform-pressure as
sumption is acceptable.