Thermodynamic and kinetic study of NO reduction by pyridine/pyrrole during biomass tar reburning: the quantum chemical m
- PDF / 1,604,714 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 13 Downloads / 164 Views
ORIGINAL ARTICLE
Thermodynamic and kinetic study of NO reduction by pyridine/pyrrole during biomass tar reburning: the quantum chemical method approach Shanhui Zhao 1,2 & Linghai Chen 1 & Xiaolong Bi 1 & Wanjun Xu 1 Received: 6 July 2020 / Revised: 14 September 2020 / Accepted: 24 September 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract NOx emission is a serious problem during fossil fuel combustion. Novel reburning fuels, namely, nitrogen-containing tar compounds, including pyridine and pyrrole were taken into consideration for NO reduction and investigated by quantum chemical method. Theoretical calculation results show that pyridine could first decompose into small species, such as CN and hydrocarbon radicals, then reduce NO to N2. The decomposition of pyridine should overcome quite high energy barrier and adsorb a large amount of heat. This pathway may occur at high temperature zone, such as core flame zone of pulverized coal fired boiler. As soon as pyridine decomposes, the active intermediates (CN radical, etc.) could reduce NO very quickly. The direct reduction of NO by pyridine molecule should overcome lower energy barrier, which could occur at wider temperature range. Pyrrole is less thermostable than pyridine; the energy barriers of pyrrole cracking and direct reduction of NO stay at same level. Therefore, the reburning efficiency of pyrrole may be better at lower temperature than pyridine. Theoretical calculations indicate that nitrogen-containing tar compounds produced during biomass pyrolysis/gasification could have good performance for NO reduction in pulverized coal fired boiler as well as biomass or MSW furnace. Keywords NO reduction . Tar . Reburning . Quantum chemical computation
1 Introduction With the extensive use of fossil fuels, environmental pollution and climate change become prominent problems in recently years. Nitrogen oxide is one of the main atmospheric pollutants released during the combustion of coal, biomass, and other fuels. In developing countries, such as China, controlling the production of nitrogen oxides during combustion process has become a research focus in recent years. Reburning technology is to use secondary fuel, also known as reburning fuel, as a reducing agent to reduce NOx emission in furnace [1, 2]. Party et al. [3] first found that using hydrocarbons can reduce NOx emissions. Pulverized coal and natural gas are the most important reburning fuels in the early research work. In recent years, biomass is used as reburning fuel, which has * Shanhui Zhao [email protected] 1
Nanjing Institute of Technology, Nanjing, China
2
Shanghai Jiao Tong University, Shanghai, China
some advantage over coal [4–6]. However, directly using biomass for reburning in pulverized coal furnace brings quite a lot of operation problems, e.g., ash deposition problem caused by alkali metals and high temperature corrosion problems [7]. Recently, biomass gasification coupled with pulverized coal combustion for efficient utilization of biomass resources as well as
Data Loading...
