Figure 1.
Operating principle of chemical heat pump. (a) Heat Storing Step (b) Heat Releasing Step.
Figure 1.
Operating principle of chemical heat pump. (a) Heat Storing Step (b) Heat Releasing Step.
Figure 2.
Samples of (a) Kawara limestone, (b) Ofunato limestone and (c) Garou limestone.
Figure 2.
Samples of (a) Kawara limestone, (b) Ofunato limestone and (c) Garou limestone.
Figure 3.
Schematic diagram of experimental unit. (a) TGA-51 (b) muffle furnace. ①.
Figure 3.
Schematic diagram of experimental unit. (a) TGA-51 (b) muffle furnace. ①.
Figure 4.
Hydration conversion and the heat output of Kawara CaO, Ofunato CaO and Garou CaO.
Figure 4.
Hydration conversion and the heat output of Kawara CaO, Ofunato CaO and Garou CaO.
Figure 5.
Hydration conversion after decarbonization in muffle furnace. (a) Ofunato CaO (b) Kawara CaO.
Figure 5.
Hydration conversion after decarbonization in muffle furnace. (a) Ofunato CaO (b) Kawara CaO.
Figure 6.
XRD pattern of Ofunato CaO after decarbonization at 1223 K, 1273 K and 1573 K.
Figure 6.
XRD pattern of Ofunato CaO after decarbonization at 1223 K, 1273 K and 1573 K.
Figure 7.
Hydration conversion (a) Ofunato CaO (b) Kawara CaO.
Figure 7.
Hydration conversion (a) Ofunato CaO (b) Kawara CaO.
Figure 8.
Hydration conversion of Ofunato CaO in TGA-51 after decarbonization at 1223 K for 5 h in muffle furnace.
Figure 8.
Hydration conversion of Ofunato CaO in TGA-51 after decarbonization at 1223 K for 5 h in muffle furnace.
Figure 9.
Hydration conversion of Ofunato CaO after decarbonization at 1223 K in TGA-51.
Figure 9.
Hydration conversion of Ofunato CaO after decarbonization at 1223 K in TGA-51.
Figure 10.
Hydration conversion and the heat output per 1 kg of Ofunato CaO in TGA-51 after decarbonization at 1223 K for 5 h in muffle furnace.
Figure 10.
Hydration conversion and the heat output per 1 kg of Ofunato CaO in TGA-51 after decarbonization at 1223 K for 5 h in muffle furnace.
Figure 11.
Dehydration conversion of Ofunato CaO in TGA-51 after decarbonization at 1223 K for 5 h in muffle furnace.
Figure 11.
Dehydration conversion of Ofunato CaO in TGA-51 after decarbonization at 1223 K for 5 h in muffle furnace.
Figure 12.
The heat storage and the heat release per 1 kg of Ofunato CaO in TGA-51.
Figure 12.
The heat storage and the heat release per 1 kg of Ofunato CaO in TGA-51.
Figure 13.
SEM images of 710–1000 µmφ (a) Ofunato CaO, (b) Ofunato Ca(OH)2 after 1st hydration reaction, (c) Ofunato CaO after 1st dehydration reaction after decarbonization at 1223 K for 5 h in muffle furnace.
Figure 13.
SEM images of 710–1000 µmφ (a) Ofunato CaO, (b) Ofunato Ca(OH)2 after 1st hydration reaction, (c) Ofunato CaO after 1st dehydration reaction after decarbonization at 1223 K for 5 h in muffle furnace.
Figure 14.
SEM images of 710–1000 µmφ (a) Ofunato CaO, (b) Ofunato Ca(OH)2 after 1st hydration reaction, (c) Ofunato CaO after 1st dehydration reaction after decarbonization without keeping time in TGA-51.
Figure 14.
SEM images of 710–1000 µmφ (a) Ofunato CaO, (b) Ofunato Ca(OH)2 after 1st hydration reaction, (c) Ofunato CaO after 1st dehydration reaction after decarbonization without keeping time in TGA-51.
Figure 15.
The picture of white particles (Ofunato CaO) and black particles (Ofunato CaO) after decarbonization at 1223 K for 5 h in a muffle furnace.
Figure 15.
The picture of white particles (Ofunato CaO) and black particles (Ofunato CaO) after decarbonization at 1223 K for 5 h in a muffle furnace.
Figure 16.
Picture of black particles of Ofunato Ca(OH)2) after a 4th hydration in the TGA-51 system.
Figure 16.
Picture of black particles of Ofunato Ca(OH)2) after a 4th hydration in the TGA-51 system.
Figure 17.
Hydration conversion in TGA-51 system after decarbonization at 1223 K for 5 h in a muffle furnace. (a) white particle (Ofunato CaO) (b) black particle (Ofunato CaO).
Figure 17.
Hydration conversion in TGA-51 system after decarbonization at 1223 K for 5 h in a muffle furnace. (a) white particle (Ofunato CaO) (b) black particle (Ofunato CaO).
Table 1.
Chemical compositions (mass%) of different natural limestone samples. (measured by a ZSX Primus II Scanning X-ray fluorescence analyzer, Rigaku, Japan).
Table 1.
Chemical compositions (mass%) of different natural limestone samples. (measured by a ZSX Primus II Scanning X-ray fluorescence analyzer, Rigaku, Japan).
Sample | Ig.Ioss | SiO2 | Al2O3 | Fe2O3 | CaO | MgO | SO3 | K2O | TiO2 | Others | Purity (%) |
---|
Kawara limestone | 43.22 | 0.00 | 0.03 | 0.02 | 56.08 | 0.28 | 0.00 | 0.00 | 0.00 | 0.02 | 99.66 |
Ofunado limestone | 42.13 | 1.26 | 0.84 | 0.38 | 54.83 | 0.18 | 0.02 | 0.11 | 0.05 | 0.14 | 96.96 |
Garou limestone | 42.94 | 2.19 | 0.13 | 0.09 | 51.50 | 2.38 | 0.05 | 0.00 | 0.00 | 0.15 | 95.01 |
Table 2.
Different decarbonization, hydration and dehydration temperature conditions in TGA-51.
Table 2.
Different decarbonization, hydration and dehydration temperature conditions in TGA-51.
Samples | Pre-Heating | Decarbonization | Hydration | Dehydration |
---|
Temperature |
---|
− | 673–683 K | 1183 K | 1223 K | 783 K | 373 K | 783 K |
---|
Three different kinds of CaO | 7 K/min | 3 K/min | − | 3 K/min | 2 K/min | 2 K/min |
Ofunato CaO | 10 K/min | − | 10 K/min | 2 K/min | 2 K/min | 2 K/min |
Table 3.
Specific surface area and mean pore diameter of Ofunato CaO after decarbonization at 1273 K and 1573 K in muffle furnace.
Table 3.
Specific surface area and mean pore diameter of Ofunato CaO after decarbonization at 1273 K and 1573 K in muffle furnace.
Sample | Ofunato CaO |
---|
Heat treatment temperature (K) | 1273 | 1573 |
Specific surface area (m2/g) | 3.31 | 1.11 |
Mean pore diameter (4V/A) (nm) | 28.41 | 16.95 |
Table 4.
Specific surface area of Ofunato CaO and Ofunato Ca(OH)2 after decarbonization at 1223 K for 5 h in a muffle furnace.
Table 4.
Specific surface area of Ofunato CaO and Ofunato Ca(OH)2 after decarbonization at 1223 K for 5 h in a muffle furnace.
Sample | Ofunato CaO | Ofunato Ca(OH)2 |
---|
Heat treatment temperature (K) | 1223 K | 1223 K |
Specific surface area (m2/g) | 6.69 | 12.20 |
Table 5.
Identified elements in Ofunato Ca(OH)2 (white particles) after the 1st hydration in the TGA-51 system and decarbonization in a muffle furnace (measured by Energy Dispersive X-ray Spectroscopy).
Table 5.
Identified elements in Ofunato Ca(OH)2 (white particles) after the 1st hydration in the TGA-51 system and decarbonization in a muffle furnace (measured by Energy Dispersive X-ray Spectroscopy).
Fitting Coefficient: 0.69 |
---|
Element | (keV) | Mass% | Error% | Mol% | Compound | Compound Mass% | K |
---|
Mg K | 1.25 | 0.14 | 3.20 | 0.33 | MgO | 0.24 | 0.11 |
Fe K | 6.40 | 0.96 | 15.96 | 1.04 | Fe3O4 | 1.33 | 1.13 |
Al K | 1.49 | 0.16 | 3.50 | 0.16 | Al2O3 | 0.30 | 0.15 |
Si K | 1.74 | 0.67 | 4.16 | 1.35 | SiO2 | 1.44 | 0.74 |
Ca K | 3.69 | 69.10 | 5.34 | 97.11 | CaO | 96.69 | 97.88 |
O | − | 28.96 | − | − | − | − | − |
Total | − | 100.00 | − | 100.00 | − | 100.00 | − |
Table 6.
Identified elements in Ofunato Ca(OH)2 (black particles) after a 1st hydration in the TGA-51 system and decarbonization in a muffle furnace (measured by Energy Dispersive X-ray Spectroscopy).
Table 6.
Identified elements in Ofunato Ca(OH)2 (black particles) after a 1st hydration in the TGA-51 system and decarbonization in a muffle furnace (measured by Energy Dispersive X-ray Spectroscopy).
Fitting Coefficient: 0.69 |
---|
Element | (keV) | Mass% | Error% | Mol% | Compound | Compound Mass% | K |
---|
Mg K | 1.25 | 2.40 | 2.50 | 6.06 | MgO | 3.98 | 2.56 |
Fe K | 6.40 | 6.26 | 12.82 | 7.40 | Fe2O3 | 8.66 | 9.71 |
Al K | 1.49 | 8.09 | 2.82 | 9.21 | Al2O3 | 15.29 | 9.84 |
Si K | 1.74 | 10.22 | 3.62 | 22.36 | SiO2 | 21.87 | 13.64 |
Ca K | 3.69 | 35.88 | 4.49 | 54.97 | CaO | 50.20 | 64.24 |
O | − | 37.14 | − | − | − | − | − |
Total | − | 100.00 | − | 100.00 | − | 100.00 | − |