scholarly journals Investigation of the activity of unburned carbon as a catalyst in the decomposition of NO and NH3

Fuel ◽  
2022 ◽  
Vol 309 ◽  
pp. 122170
Author(s):  
Anna M. Kisiela-Czajka ◽  
Sylwia Hull ◽  
Andrzej Albiniak
2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.


Author(s):  
Da Shi ◽  
Jianbo Zhang ◽  
Xinjuan Hou ◽  
Shaopeng Li ◽  
Huiquan Li ◽  
...  

2018 ◽  
Vol 41 ◽  
pp. 01042
Author(s):  
Vasilii Murko ◽  
Veniamin Khyamyalyainen ◽  
Marina Baranova

Effective utilization of ash-and-slag waste generated by coalfired power plants can help significantly to reduce the negative impact on the environment and improve their economic performance. Studies have been made of the mineralogical composition of ash-and-slag wastes obtained after the combustion of water-coal fuel based on fine-dispersed coal-washing waste (filter cake) in a specially designed boiler with a vortex combustion system. The possibility of effective use of ash-and-slag wastes for the production of building materials, primarily mortar mixes, widely used for mining works on mine openings, laying the worked out space, etc. (high content of silicon oxide and aluminum oxide is combined with a low carbon content in other words a negligible unburned carbon loss). The optimum percentage ratio of the initial components of the filling mixture based on ash-and-slag wastes and crushed rock (granulated slag) has been established. The results of experimental tests of hardening tabs on the strength under uniaxial compression are presented. It has been established that a sample containing 18% of ash-and-slag wastes, 33% of a granulated slag and 19% of cement, corresponds to the required technological parameters for the strength and cement content.


Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5077 ◽  
Author(s):  
Jiseok Lee ◽  
Seunghan Yu ◽  
Jinje Park ◽  
Hyunbin Jo ◽  
Jongkeun Park ◽  
...  

For renewable electricity production, biomass can fully displace coal in an existing power plant with some equipment modifications. Recently, a 125 MWe power plant burning mainly anthracite in Korea was retrofitted for dedicated wood pellet combustion with a change of boiler configuration from arch firing to wall firing. However, this boiler suffers from operational problems caused by high unburned carbon (UBC) contents in the bottom ash. This study comprises an investigation of some methods to reduce the UBC release while achieving lower NOx emissions. The computational fluid dynamics approach was established and validated for typical operating data. Subsequently, it was applied to elucidate the particle combustion and flow characteristics leading to the high UBC content and to evaluate the operating variables for improving the boiler performance. It was found that the high UBC content in the bottom ash was a combined effect of the poor fuel grindability and low gas velocity in the wide burner zone originating from the arch-firing boiler. This prevented the operation with deeper air staging for lower NOx emissions. Reducing the particle size to <1.5 mm by modifying mills or pretreating the fuel using torrefaction was the only effective way of lowering the UBC and NOx emissions with deeper air staging while increasing the boiler efficiency.


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