A Review of Urea Pyrolysis to Produce NH₃ Used for NO_x 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