Embracing a Green Future with Ultra-low Emission Technologies of Coal-fired Power Plants in China

Transcription

1 Embracing a Green Future with Ultra-low Emission Technologies of Coal-fired Power Plants in China Cao Yuchun Dept. of Thermal Power Engineering Changzhou University SAMK, Mar 9, 2016

2 Outline Introduction Energy consumption in China Emission from coal-power plants Multi-pollutants simultaneous removal strategy Technical routines for pollutants deep removal Integrated system design for flue gas cleaning Application of the retrofitted projects Challenges and Prospects Summary 1

3 Billion tec (%) Growth of the total energy consumption in China Energy consumption Growth rate(%) Year From National Bureau of Statistics of China,

4 Energy consumption structure in China 100% 80% 60% 40% Renewable Natural gas Oil Coal 20% 0% From National Bureau of Statistics of China, 3

5 Comparison of Energy consumption structure Energy consumption structure in different countries (2014) Renewable Hydro Nuclear Coal Natural gas Oil USA France Germangy Japan China From BP Statistical Review of World Energy 2015, 4

6 Energy Structure of Power plants in China 100% 80% 60% Coal-fired Wind 40% Hydro Nuclear 20% 0% From National Bureau of Statistics of China, 5

7 Emission from coal-fired power plants SOx NOx PM Heavy metals Others 6

8 Challenges brought by the fossil fuel combustion Chemical reaction NO hv RO 2, HO 2, VOCs Emission O 3 NO 2 SO 2 OH H 2 O 2 N 2 O 5 H 2 SO 4 NH 3 HNO 3 Primary PM NO 3- SO 2-4 NH + 4 SNA SOA 7

9 Challenges brought by the fossil fuel combustion Cheng Z, et al. Environment international, 2016, 89:

10 Latest emission limits for coal-fired boiler in China Item Conditions Current limits (mg/nm 3 ) New emission limits Non key areas Key areas Monitoring position SO 2 Existing 450/1200 NOx (NO 2 ) New built (1) (1) 50 Existing New built (2) 100 Inside or outside of the stack PM Existing New built Hg and Others All 无 0.03 Unit: mg/m 3 From GB , Emission standard of air pollutants for thermal power plants, 9

11 Local emission standard for coal-fired power plants Province PM SO 2 NOx Date Issued Completion Time Zhejiang Dec Anhui Mar Henan Dec Jiangsu Nov Hebei Mar Shanxi Mar Fujian Shandong Dec Hainan Apr Guangxi May Tianjin May Guangdong May Unit: mg/m 3 10

12 Deep removal flow diagram of pollutants 11

13 Multi-pollutants simultaneous removal strategy Pollutants SCR FGC Low Temp. WESP WFGD ESP (Option) PM ο SO 2 ο ο ο ο SO 3 NO x ο ο Hg Notes: -Directly, -Directly simultaneous, -Indirectly simultaneous, ο-no effects 12 12

14 Multi-pollutants simultaneous removal strategy Single device model Simultaneous removal model FGD SOx SOx SCR NOx Equipment NOx ESP PM PM Equipment Hg Remove the primary pollutant directly or others indirectly Create suitable work conditions for other equipment as possible 13

15 Integrated system design for flue gas cleaning Low NO x Combustion Technology Boiler High efficiency catalyst for SCR ( Hg Hg 2+ ) SCR AH Reduce the flue gas temperature (about 90 ) ; SO 3 adsorption by fly ash; Improve particle size after the ESP exit. FGC ESP Tray design optimization; using novel nozzle; Improved the demister performance; Improve nozzle arrangement and absorption for NO 2 removal. FGD WESP FGR S T A C K Hg Hg 2+ Reduce the specific resistance and improve the breakdown voltage. Further removal of the small PM (Option). 14

16 Technical routines for deep removal of pollutants Technical routine 1 Low Temperature ESP Boiler SCR AH FGC ESP FGD WESP Option FGR S T A C K Key equipment Technical routine 2 Boiler SCR FGC AH ESP FGD WESP Option FGR S T A C K Key equipment Rotating electrode ESP Dr. Cao Yuchun, Changzhou University 15

17 Low Temperature ESP Flue gas temp. vs Electrical resistivity of fly ash Flue gas temp. vs PM collecting efficiency Nakayama Y, et al. Hiroshima Research & Development Center, 2011:

18 Low temperature ESP application at Jianxin Air preheater Heat recovery 1000MW power plant at Jiaxin ESP Dr. Cao Yuchun, Changzhou University 17

19 Wet ESP for flue gas cleaning 1 Chamber 2 3 Flue gas Corona Dust Minus Ions Orifice plate Flue gas Chamber 7 Ash collection Hammer Ash storage Chamber Hopper 7 Spray Nozzle 6 吸引力 Pit Hopper Dust Capture 18

20 Wet ESP for flue gas cleaning Wet ESP for flue gas cleaning 19

21 On-site Wet ESP installing 灰斗 烟箱 20

22 Diagram of rotating electrode ESP Rotating drive Insulator chamber Discharge electrode Cathode rapping Fixed electric field Rotating electric field Rotating anode plate Anode cleaning device 21

23 Two FGD design models for deep SO 2 removal Wet scrubber inside FGD Wet scrubber outside FGD 22

24 High efficiency FGD design for deep SO 2 removal PH Wet scrubber Single tower Double zone 23

25 Novel design for NOx control NH 3 NOx control reactor To air heater N 2 & H 2 O NOx Catalysts 4NO + 4NH 3 + O 2 4N 2 + 6H 2 O NO + NO 2 + 2NH 3 2N H 2 O Vertical reactor Horizontal reactor 24

26 Technologies adopted by different power plants Location PM Emission Zhejiang Jiahua, MW Low temperature ESP+Wet FGD+Wet ESP <5 Zhejiang Luheng, MW Zhejiang Zhoushan, 1 350MW Guangdong Hengyun, 2 700MW Guangdong Zhuhai, 2 300MW Jiangsu Changsu, 4 330MW Rotating electrode ESP+Wet FGD +Wet ESP Rotating electrode ESP+Wet FGD +Wet ESP Low temperature ESP+Wet FGD+Wet ESP <5 Electrostatic-fabric integrated precipitator(efip)+wet FGD+Wet ESP Electrostatic-fabric integrated precipitator(efip)+wet FGD+Wet ESP Huaneng Beijing, 1 200MW Rotating electrode ESP+Wet FGD <10 Shanghai Waigaoqiao, MW Dr. Cao Yuchun, Changzhou University 25 <5 <5 <10 <10 ESP+Wet FGD <10 Jiangxi Jiujiang, 2 300MW ESP+Wet FGD+Wet ESP <10 Unit: mg/m 3

27 Integrated system design for flue gas cleaning Application at a 1000MW coal-fired power plant NOx/mg/Nm 3 Boiler SCR AH Heat recovery ESP 引风机 FGD WESP < 50 < 100 AH Stack Gas-fired power plant SO 2 mg/nm < 35 < 50 Dust/mg/Nm < 5 < 20 Temperature/ /80 > Dr. Cao Yuchun, Changzhou University 26

28 Challenges and prospects Scientific evaluation the current retrofitted projects. System performance Costs Problems existed in the present retrofitted projects. Low temperature corrosion on ESP collection electrodes Equipment performance stability Technical adaptability for different kind of coal-fired power plant Unit Capacity Coal parameters Boiler type Accuracy of CEMS (Continuous Emission Monitoring System) Technical supports for the future integrated design optimization toward the different power plants. 27

29 Summary According the latest emission limits, multi-pollutants simultaneous removal strategy will be expected carried out for a widely utilization for the whole coal-fired power plants in China. Through the design optimization of the integrated flue gas cleaning system, multi-pollutants can be deeply simultaneous removed. The technical routine choice depends on the coal-fired power plant itself. Based on the practice of the present retrofitted projects, the coal-fired power plants are ongoing further technologies update in China. 28

30 Embracing a green future of coal-fired power 29

31 Thanks for your attention! Any comments are welcome!