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Large-eddy simulation of pulverized coal jet flame - Effect of oxygen concentration on NOx formation


Type

Article

Change log

Authors

Muto, M 
Watanabe, H 
Kurose, R 
Komori, S 
Balusamy, S 

Abstract

Large-eddy simulation is applied to a laboratory-scale open-type pulverized coal flame generated by a triple stream burner, and the NO production and reduction in oxy- fuel condition are investigated for the first time. Pulverized Cerrejon coal which is classified as bituminous coal is used as a fuel. The results show that regardless of the equivalence ratio, as the O2 concentration increases from 21% to 40%, O2 consumption becomes marked because gas temperature rises and oxidation reaction is enhanced by the higher concentration of O2. Also, NO is formed rapidly due to the oxidation reaction of nitrogen from volatile matter of coal, and its concentration reaches a few hundred ppm further downstream. After the rapid formation, in the case of equivalence ratio larger than unity, NO decreases, because the reducing atmosphere becomes dominant due to the lack of O2. The trend becomes signi cant as the O2 concentration in the carrier gas increases from 21% to 40%. In the case of equivalence ratio less than unity, on the other hand, NO does not decrease clearly, because the oxidizing atmosphere contributes to the further formation of NO. Present study shows the usefulness of the large-eddy simulations for predicting the characteristics of pulverized coal flames.

Description

Keywords

Pulverized coal combustion, Oxy-fuel combustion, NO formation, Swirl jet flame, Large-eddy simulation

Journal Title

Fuel

Conference Name

Journal ISSN

0016-2361
1873-7153

Volume Title

142

Publisher

Elsevier BV
Sponsorship
This research was partially supported by \Strategic Programs for Innovative Research (SPIRE) - Field No. 4: Industrial Innovations" from MEXT (Ministry of Education, Culture, Sports, Science, and Technology) using computational resources of the HPCI sys- tem provided by RIKEN Advanced Institute for Computational Science through the HPCI System Research Project (Project ID: hp120294, hp130018). See also (http:// www. uid.me.kyoto-u.ac.jp/members/kurose/hpci.html). Experiments at Cambridge were supported by EPSRC, within the Oxycap Oxyfuels Grant EP/G062153/1.