Review Article
A Review of Urea Pyrolysis to Produce NH3 Used for NOx Removal
Table 3
Test of fluidized bed materials for the thermohydrolysis of 50% urea solution.
| Bed material | Particle diameter (mm) | Reactor diameter (mm) | Volume of bed material (ml) | Air flow (LN/h) | Urea dosage type | Urea solution dosage (g/h) | Bed loading (g/(h·ml)) | Fluidized bed temperature (°C) | (%) | YHNCO (%) | Urea slip (%) |
| γ-Al2O3 “Uetikon1” | 0.2–0.315 | 20 | 15 | 150 | From top | 185 | 6.2 | 300 | 99 | 1 | 0.4 | 275 | 99 | 1 | 0.4 | 250 | 100 | 0 | 0.4 | 225 | 102 | 0 | 0.5 | 200 | 96 | 1 | 1.2 |
| γ-Al2O3 “Uetikon1” | 0.50–0.63 | 25 | 15 | 520 | From top | 185 | 6.2 | 300 | 97 | 4 | 1.2 | 275 | 96 | 5 | 1.3 | 250 | 84 | 12 | 2.6 | 225 | 73 | 16 | 3.9 |
| γ-Al2O3 “compalox” | 0.50–0.63 | 25 | 15 | 520 | From top | 185 | 6.2 | 300 | 96 | 0 | 1 | 275 | 95 | 0 | 0.7 | 250 | 96 | 1 | 0.9 | 225 | 93 | 2 | 2.3 |
| γ-Al2O3 “puralox” | 0.2–0.315 | 20 | 15 | 150 | From top | 185 | 6.2 | 300 | 96 | 5 | 0.4 | 275 | 99 | 5 | 0.3 | 250 | 96 | 4 | 0.4 | 225 | 98 | 4 | 0.4 | 200 | 99 | 4 | 0.9 |
| γ-Al2O3 “CAT 250” | 0.50–0.63 | 50 | 60 | 1860 | From top | 340 | 2.9 | 300 | 97 | 2 | 0.7 | 275 | 98 | 3 | 0.6 | 250 | 96 | 2 | 0.6 | 225 | 97 | 3 | 0.6 | 200 | 95 | 3 | 1.2 |
| γ-Al2O3 “CAT 250” | 1.0–1.25 | 50 | 60 | 3900 | From top | 350 | 2.9 | 300 | 96 | 0 | 1.9 | 275 | 95 | 0 | 1.8 | 250 | 94 | 1 | 1.6 | 225 | 83 | 5 | 2.4 | 200 | 66 | 15 | 5 |
| γ-Al2O3 “CAT 250” | 1.0–1.25 | 50 | 60 | 3900 | From top | 350 | 2.9 | 300 | 94 | 0 | 1.1 | 275 | 94 | 1 | 1.2 | 250 | 93 | 1 | 1.3 | 225 | 89 | 6 | 2.3 |
| γ-Al2O3 “CAT 250” | 1.0–1.25 | 25 | 15 | 1109 | From top | 186 | 6.2 | 300 | 101 | 0 | 1.9 | 275 | 100 | 2 | 1.7 | 250 | 99 | 3 | 1.8 | 225 | 84 | 12 | 3.2 |
| γ-Al2O3 “condea” | 1.0–1.25 | 20 | 15 | 554 | From top | 185 | 6.2 | 300 | 89 | 5 | 5.8 | 275 | 78 | 16 | 6.1 | 250 | 69 | 23 | 6.3 |
| γ-Al2O3 “seralite 537” | 1.0–1.25 | 50 | 60 | 3900 | Into bed | 350 | 2.9 | 300 | 94 | 3 | 1.9 | 275 | 91 | 5 | 2.2 | 250 | 85 | 7 | 3 | 225 | 72 | 13 | 5 |
| α-Al2O3 “seralite 512 S” | 1.6–2.0 | 50 | 60 | 4700 | Into bed | 290 | 2.4 | 300 | 47 | 31 | 9.1 |
| α-AlOOH (boehmite) | 0.2–0.315 | 20 | 15 | 150 | From top | 185 | 6.2 | 300 | 99 | 3 | 0.8 | 275 | 94 | 4 | 0.5 | 250 | 96 | 3 | 0.8 | 225 | 95 | 5 | 0.6 | 200 | 96 | 5 | 0.7 |
| SiO2 “aerosil” | 0.50–0.63 | 25 | 15 | 410 | From top | 185 | 6.2 | 300 | 70 | 25 | 4.2 |
| AlSiOx (molochite) | 0.22–0.50 | 20 | 15 | 150 | From top | 4.5 | 0.02 | 400 | 61 | 25 | n.d. | 350 | 55 | 34 | n.d. | 300 | 38 | 33 | n.d. | 250 | 24 | 20 | n.d. |
| MgSiOx “florisil” | 0.50–0.63 | 25 | 15 | 400 | From top | 185 | 6.2 | 300 | 90 | 8 | 2.3 | 275 | 86 | 7 | 2.1 | 250 | 83 | 9 | 3 |
| TiO2 “macrosorb T” | 0.2–0.315 | 20 | 15 | 150 | From top | 185 | 6.2 | 300 | 104 | 1 | 0.7 | 275 | 102 | 1 | 0.8 | 250 | 95 | 4 | 2.7 | 225 | 62 | 8 | 5.9 |
| TiO2 “7702” | 0.50–0.63 | 25 | 15 | 520 | From top | 185 | 6.2 | 300 | 98 | 0 | 1.5 | 275 | 99 | 0 | 1.2 | 250 | 99 | 0 | 1 | 225 | 99 | 1 | 1 | 200 | 98 | 2 | 1.6 |
| V2O5/WO3-TiO2 | 0.315–0.50 | 25 | 15 | 356 | From top | 185 | 6.2 | 300 | 96 | 1 | 0.6 | 275 | 96 | 1 | 0.6 | 250 | 90 | 6 | 1.1 | 225 | 87 | 6 | 1.5 | 200 | 82 | 6 | 2.9 |
| Molsieve 5 Å | 0.2–0.315 | 20 | 15 | 150 | From top | 94 | 3.1 | 300 | 93 | 7 | 0.9 | 275 | 58 | 21 | 7.2 |
| Molsieve “13X” | 0.50–0.63 | 25 | 15 | 410 | From top | 185 | 6.2 | 300 | 93 | 2 | 0.7 | 275 | 76 | 13 | 1.2 | 250 | 43 | 20 | 5.5 |
| H-MOR | ca.2.(2–4) | 50 | 60 | 3900 | From top | 350 | 2.9 | 300 | 85 | 4 | 2.6 | 275 | 83 | 6 | 2.8 |
| H-ZSM-5 | ca.2.(2–4) | 50 | 60 | 3900 | From top | 350 | 2.9 | 300 | 72 | 19 | 3.1 | 275 | 66 | 25 | 3.6 |
| Dealuminated Y | ca.2.(2–4) | 50 | 60 | 3900 | From top | 350 | 2.9 | 300 | 52 | 35 | 5 | 275 | 51 | 36 | 5.6 |
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