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POSSIBILITY OF ACTIVE CARBON RECYCLE ENERGY SYSTEM
Figure 2: Concept of ACRES
C x H y O z + O 2
E
W
Material
CO 2 + H 2 O
CO 2 reduction/oxidation
Carbon dioxide system
have quite a high affinity with common manufacturing industries. If the carbon recycle system can be
established thermally and kinetically, it is expected that the system would be easily integrated into
conventional industries. A natural carbon recycle energy system has already existed in plant life in
nature, and is an ideal recycle system. However, the potential amount of biomass is not sufficient for
a modern society. Specifically, it is less than 10% of all energy demand in Japan. The natural recycle
system thus cannot sustain energy demand in Japan (Kameyama, 2005). Therefore, an artificial active
carbon recycle system was proposed as ACRES in this study. The feasibility of ACRES was discussed
from enthalpy balances in this paper.
Structure of ACRES
The structure of ACRES shown in Figure 3 consists of three elemental processes of hydrocarbon usage,
CO 2 recovery and separation, and hydrocarbon regeneration. In the usage process, the hydrocarbon can
be used for both heat source and material. CO 2 generated from hydrocarbon consumption is recovered
by physical and chemical sorptions. Sorbed CO 2 in a sorption material is separated thermally from
material by a heat input. This process produces highly concentrated CO 2 . The recovered CO 2 is
regenerated into hydrocarbon in the regeneration process. The regeneration process is endothermic
and requires energy input. In ACRES, the total energy input at recovery and separation (E S ), and
regeneration (E R ) should be larger than the energy output at the usage process (E U ).
E S + E R > E U (1)
ACRES is energy consumption process, then, a discussion of the energy balance of the system is
required for the feasibility evaluation of the system.
Figure 3: The three elemental processes in ACRES
Recovery and
separation
Recov./Sep. energy
Effluent CO 2
Usage
Separated CO 2
Regen. energy
Materials
Energy
Regeneration
Hydro carbon
Input E > output E
Carbon flow
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