Wet flue gas desulfurization performance of 330 MW coal-fired power unit based on computational fluid dynamics region identification of flow pattern and transfer process

doi:10.1016/j.cjche.2020.08.004

Chinese Journal of Chemical Engineering ›› 2021, Vol. 29 ›› Issue (1): 13-26.DOI: 10.1016/j.cjche.2020.08.004

• Fluid Dynamics and Transport Phenomena • Previous Articles Next Articles

Wet flue gas desulfurization performance of 330 MW coal-fired power unit based on computational fluid dynamics region identification of flow pattern and transfer process

Jiangyuan Qu^1,2, Nana Qi^1,2, Kai Zhang^1,2, Lifeng Li³, Pengcheng Wang³

1 Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation, North China Electric Power University, Beijing 102206, China;
2 Key Laboratory of Power Station Energy Transfer Conversion and System(North China Electric Power University), Ministry of Education, Beijing 102206, China;
3 Shanxi Hepo Power Generation Company Limited, Yangquan 045011, China

Received:2020-06-21 Revised:2020-08-03 Online:2021-04-02 Published:2021-01-28
Contact: Nana Qi
Supported by:
This work was supported by the National Natural Science Foundation of China (51706070 and U1910215), and the Fundamental Research Funds for the Central Universities (2018ZD03, 2020MS008 and 2020MS078).

Wet flue gas desulfurization performance of 330 MW coal-fired power unit based on computational fluid dynamics region identification of flow pattern and transfer process

Jiangyuan Qu^1,2, Nana Qi^1,2, Kai Zhang^1,2, Lifeng Li³, Pengcheng Wang³

1 Beijing Key Laboratory of Emission Surveillance and Control for Thermal Power Generation, North China Electric Power University, Beijing 102206, China;
2 Key Laboratory of Power Station Energy Transfer Conversion and System(North China Electric Power University), Ministry of Education, Beijing 102206, China;
3 Shanxi Hepo Power Generation Company Limited, Yangquan 045011, China

通讯作者: Nana Qi
基金资助:
This work was supported by the National Natural Science Foundation of China (51706070 and U1910215), and the Fundamental Research Funds for the Central Universities (2018ZD03, 2020MS008 and 2020MS078).

Abstract

Abstract: Wet Flue Gas Desulfurization (WFGD) unit based upon spray scrubber has been widely employed to control SO₂ emissions from flue gas in coal-fired power plant. To clarify the dependence of desulfurization performance on inter-phase transfer behaviors with non-ideal contacting patterns of flue gas and slurry droplets, three regions in spray scrubber are distinguished in terms of gas-slurry flow structures using CFD method in the Eulerian-Lagrangian framework. A comprehensive model is established by involving the transfer process between two phases and chemical reactions in aqueous phase, which is validated with the measured data from a WFGD scrubber of 330 MW coal-fired power unit. Numerical results show that the overall uniformity degree of flue gas in whole scrubber is largely determined by the force-balanced droplets in the middle part of scrubber, which is dominated by counter-current mode. Both momentum transfer behavior and SO₂ chemical absorption process present the synchronicity with the evolution of gas-slurry flow pattern, whilst the heat transfer together with H₂O evaporation has little effect on overall absorption process. Three regions are firstly defined as Gas Inlet Region (GIR), Dominant Absorption Region (DAR) and Slurry Dispersed Region (SDR) from the bottom to top of scrubber. SO₂ is mainly scrubbed in DAR, which provides much more intensive interaction between two phases compared to GIR or SDR. A better understanding of the desulfurization process is obtained from the fundamental relationship between transport phenomena and chemical reactions based upon the complicated hydrodynamics of gas-slurry two-phase flow, which should be useful for designing and optimizing the scrubber in coal-fired power unit.

Key words: Wet flue gas desulfurization, Gas–liquid flow, Eulerian–Lagrangian model, Flow pattern, Transport processes, Absorption

摘要： Wet Flue Gas Desulfurization (WFGD) unit based upon spray scrubber has been widely employed to control SO₂ emissions from flue gas in coal-fired power plant. To clarify the dependence of desulfurization performance on inter-phase transfer behaviors with non-ideal contacting patterns of flue gas and slurry droplets, three regions in spray scrubber are distinguished in terms of gas-slurry flow structures using CFD method in the Eulerian-Lagrangian framework. A comprehensive model is established by involving the transfer process between two phases and chemical reactions in aqueous phase, which is validated with the measured data from a WFGD scrubber of 330 MW coal-fired power unit. Numerical results show that the overall uniformity degree of flue gas in whole scrubber is largely determined by the force-balanced droplets in the middle part of scrubber, which is dominated by counter-current mode. Both momentum transfer behavior and SO₂ chemical absorption process present the synchronicity with the evolution of gas-slurry flow pattern, whilst the heat transfer together with H₂O evaporation has little effect on overall absorption process. Three regions are firstly defined as Gas Inlet Region (GIR), Dominant Absorption Region (DAR) and Slurry Dispersed Region (SDR) from the bottom to top of scrubber. SO₂ is mainly scrubbed in DAR, which provides much more intensive interaction between two phases compared to GIR or SDR. A better understanding of the desulfurization process is obtained from the fundamental relationship between transport phenomena and chemical reactions based upon the complicated hydrodynamics of gas-slurry two-phase flow, which should be useful for designing and optimizing the scrubber in coal-fired power unit.

关键词: Wet flue gas desulfurization, Gas–liquid flow, Eulerian–Lagrangian model, Flow pattern, Transport processes, Absorption

Jiangyuan Qu, Nana Qi, Kai Zhang, Lifeng Li, Pengcheng Wang. Wet flue gas desulfurization performance of 330 MW coal-fired power unit based on computational fluid dynamics region identification of flow pattern and transfer process[J]. Chinese Journal of Chemical Engineering, 2021, 29(1): 13-26.

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Wet flue gas desulfurization performance of 330 MW coal-fired power unit based on computational fluid dynamics region identification of flow pattern and transfer process

Wet flue gas desulfurization performance of 330 MW coal-fired power unit based on computational fluid dynamics region identification of flow pattern and transfer process

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