Prediction of Combustion Behavior in a Boiler Fired by Mixture of Vietnamese Anthracite and Coal Gas Using CFD

Abstract:

The domestic anthracite is the most important fuel for Vietnamese thermal power plants. Due to high carbon percentage and low volatile matter it is difficult to ignite and to burn out the domestic anthracite. The rest carbon in ash is very high, in some cases approximately 40 %. To solve this problem some methods have been tested. In this research a mixture of anthracite and coal gas is considered. The purpose of the research is to describe a combustion behavior in a boiler, namely temperature, carbon and volatile matter distributions using CFD. The mixture consists of 4.3 % coal gas and 95.7% anthracite in mass. The boiler is divided into two combustion zones, the main zone 1 and the zone 2, to extend combustion area and through it to improve burning conditions for anthracite particles and to reduce NOx formation. All the anthracite mass and 1/3 coal gas volume are delivered into the zone 1, the rest of coal gas is into the zone 2. The CFD simulation is used for the zone 1. The simulation findings show that anthracite particles are ignited earlier, the mixture combustion develops in a larger space with higher temperatures, the carbon burning rate is remarkably improved due to coal gas. That means the domestic anthracite can be used better in boilers if some coal gas, 4 or 5 %, is mixed and the obtained ash can have lower unburned carbon, below 10%, and be more friendly for the environment.

• Periodical: Applied Mechanics and Materials (Volume 889)
• Pages: 275-280
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.889.275
• Online since: March 2019
• Authors: Gia My Tran, Duc Dung Le
• Keywords: Anthracite, Coal Gas, Combustion, Unburned Carbon

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