Electron beam flue gas treatment process for purification of exhaust ...

Electron beam flue gas treatment
process for purification of exhaust
gases with high SO 2 concentrations
Andrzej G. Chmielewski 1 , Janusz Licki 2
1 Department of Nuclear Methods in Process Engineering,
Institute of
Nuclear Chemistry and Technology,
16 Dorodna Str., 03-195 Warsaw, , Poland.
2 Department of Nuclear Energy,Institute of Atomic Energy,
05-400 Otwock-Świerk, wierk, Poland.
Tel: (+4822) 718 0144
Fax: (+4822) 779 3888
E-mail: licki@cyf.gov.pl
INTERNATIONAL CONFERENCE ON RECENT DEVELOPMENTS AND APPLICATIONS
OF NUCLEAR TECHNOLOGIES
15-17 SEPTEMBER 2008, BIAŁOWIEśA, POLAND
Main tasks
The application of the electron-beam process for
purification of flue gases with w
high SO 2 concentrations
was the purpose of this paper. The experimental
studies were concentrated on the purification of
exhaust gases
1. from combustion of high sulphur
coal
heavy fuel oil
2. and from copper smelter.
The other aim was determination of the conditions for
obtaining the highest SO 2 and NO x removal efficiencies
from above exhaust gases.
Table 1. Main parameters of industrial e-beam installations
Parameter
Flue gas flow rate
Inlet flue gas temperature
Inlet SO 2 concentration
mg/Nm 3 5150
2770
2000
concentration mg/Nm 3 820
410
600
Inlet NO concentration
x
SO 2 removal efficiency
NO x removal efficiency
Electron beam parameters
Unit
Nm 3 /h
0 C
%
%
Chengdu
TPP
China
300 000
150
80
18
800 keV,
320 kWx2
Hangzhou
TPP
China
305 400
145
85
55
800 keV,
320 kWx2
Pomorzany
EPS
Poland
270 000
140
90
70
700 keV,
260 kWx4
1

Fig. 1. Technological scheme of the industrial plant at EPS Pomorzany
Fig. 2. Schematic flow diagram of the pilot plant at TPP Kawęczyn
Fig. 3. Flow diagram of INCT laboratory plant equipped with stand for burning of mazout C-3.
1. thermostated fuel oil
2. oil burner
3. particulate and soot filters
4. orifice
5. dosage of water vapour
6. gas sampling point - process inlet
7. ammonia injection
8. process vessel
9. electron beam accelerator
10. retention chamber
11. bag filter
12. gas sampling point – process outlet
13. induced - draught fan
14. stack
15. concrete shielding wall
16. concrete shielding door
2

Fig. 4. Flow diagram of INCT laboratory plant with gas-fired boilers
1. two gas-fired boilers,
2. orifice,
3. SO2 dosage,
4. NO dosage,
5. water vapour dosage,
6. gas sampling device,
7. NH3, dosage,
8. irradiation chamber,
9. electron accelerator,
10. retention chamber,
11. bag filter,
12. gas sampling device,
13. draught fan,
14. chimney,
15. shielding walls,
16. shielding door.
α NH
3
Effect of absorbed dose
Fig. 4 presents the dose dependence of
SO 2 and NO x removal efficiency.
Dose dependence of SO 2 removal from gas
mixture with extemely high SO 2 concentration:
SO 20 : 10% vol., H: 14.5% vol., α NH3 : 0.85-0.94,
T inlet : 105-114°C
Effect of ammonia stoichiometry
3

Effect of gas temperature at inlet to proces vessel
Effect of flue gas humidity
Experimental conditions:
SO 20 : 10 % vol, H: 14-15.5 % vol.,
α NH3 : 085-0.95, T inlet : 105-116 °C
Effect of inlet high SO 2 concentration
SO 2 + *OH + M → HSO 3 + M
HSO 3 + O 2 → SO 3 + HO 2
*
NO + HO 2* → NO 2 + *OH
NO 2 + *OH + M → HNO 3 + M
4

Conclusions
Flue gases from combustion of high sulphur fossil fuels can be effectively purified
by the electron beam process. The SO 2 removal efficiency above 95 % and NO x
removal above 75 % were obtained in the optimal treatment conditions. High
removal efficiencies can be obtained by firstly properly controlling the temperature
and humidity of flue gas in a dry bottom spray cooler. Then a near stoichiometric
amount of NH 3 should be added to gas before its inlet to a process vessel.
Thirdly, the mixture should be irradiated with adequate irradiation dose in the
process vessel. The improvement in NO x removal is achieved by multi-stage
irradiation and by adequate dose distribution between irradiation stages [5]. The
gas humidity and temperature, ammonia stoichiometry and irradiation dose up 8
kGy strongly influence SO 2 removal efficiency. The synergistic effect of high SO 2
concentration on NO x removal was indicated. The collected by-product was the
mixture of ammonium sulphate and nitrate. The content of heavy metals in the byproduct
was many times lower than the values acceptable for commercial
fertilizer. In addition the formation of a valuable product in large quantities might
further reduce the operating cost of the EBFGT process depending on the market
value of fertilizer by-product.
Thank you for your
attention!
INTERNATIONAL CONFERENCE ON RECENT DEVELOPMENTS AND APPLICATIONS
OF NUCLEAR TECHNOLOGIES
15-17 SEPTEMBER 2008, BIAŁOWIEśA, POLAND
5