Permeability and thermal conductivity of host compressed natural graphite for consolidated activated carbon adsorbent
Received date: 13 Dec 2010
Accepted date: 24 Jan 2011
Published date: 05 Jun 2011
Copyright
Permeability and thermal conductivity test units were set up to study the heat and mass transfer performance of the host material, i.e. expanded natural graphite (ENG), for consolidated activated carbon (AC) adsorbent. The permeability was tested with nitrogen as the gas source, and the thermal conductivity was studied using steady-state heat source method. The results showed that the values of permeability and thermal conductivity were 10-15 to 10-12 m2 and 1.7 to 3.2 W/(m·K), respectively, while the density compressed expanded natural graphite (CENG) varied from 100 to 500 kg/m3. The permeability decreased with the increasing density of CENG, whereas the thermal conductivity increased with the increasing density of CENG. Then the thermal conductivity and permeability of granular AC were researched. It was discovered that the thermal conductivity of samples with different grain size almost kept constant at 0.36 W/(m·K) while the density was approximately 600 kg/m3. This means that the thermal conductivity was not related to the grain size of AC. The thermal conductivity of CENG was improved by 5 to 10 times compared with that of granular AC. Such a result showed that CENG was a promising host material for AC to improve the heat transfer performance, while the mass transfer performance should be considered in different conditions for utilization of adsorbent.
Bo TIAN , Liwei WANG , Zhequan JIN , Ruzhu WANG . Permeability and thermal conductivity of host compressed natural graphite for consolidated activated carbon adsorbent[J]. Frontiers in Energy, 2011 , 5(2) : 159 -165 . DOI: 10.1007/s11708-011-0145-y
Notation | |
B | Shape factors of the samples |
K | Permeability/m2 |
ma | Gas mass flowrate/(kg·s-1) |
p1 | Inlet pressure of air/Pa |
p2 | Outlet pressure of air/Pa |
qv | Gas volume flowrate/(L·min-1) |
Q | Heat flux/W |
R | Gas constant/(J·kg-1·K-1) |
S | The effective heating area of the central square plate heater/m2 |
T | Sample temperature/K |
Greek letters | |
λ | Thermal conductivity/(W·m-1·K-1) |
ΔT | Average temperature gradient/K |
Δz | Thickness of the samples/m |
μ | Gas viscosity/(Pa·s) |
ρ | Density/(kg·m-3) |
va | Axial velocity/(m·s) |
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