Jae Heun Oh

The Formation Characteristics of Tar, Ash and Clinker due to Combustion of Wood Pellet and Performance Analysis of Wood Pellet Boiler in terms of the Moisture Contents Change of the Wood Pellet

This study reports the formation characteristics of tar, ash and clinker due to a wood pellet grade and the performance analysis of wood pellet boiler in terms of the moisture contents change of the wood pellet. Tar was accumulated on the heating surface according to combustion of wood pellet, the ash was yielded on the floor of combustion chamber in a wood pellet boiler and the clinker was solidified at the burner due to combustion of the 3rd grade wood pellet. Especially, the moisture contents is important factor to define the grade. Wood of logging residues has a non-uniform moisture contents after the field process, yields of tar, ash and clinker are increased in case of combustion due to the high ash contents. For these reasons, emission of harmful compounds in the exhaust gas, decrease of boiler efficiency and the system operating errors are observed. In the performance analysis of wood pellet boiler in terms of the moisture contents change of the 1st grade wood pellet, the boiler efficiency was reduced by 27.08% with 6.6% moisture contents increase. The optimum moisture contents of wood pellet is needed to improve the boiler performance and efficiency. 에너지공학 제 권 제 호 , 23 3 (2014) Journal of Energy Engineering, Vol. 23, No. 3, pp.211~220(2014) http://dx.doi.org/10.5855/ENERGY.2014.23.3.211 To whom corresponding should be addressed. Department of Biosystems Engineering, Kangwon National University, Chuncheon, South Korea Tel : 033-250-6496 E-mail : daekim@kangwon.ac.kr

Simulation and Model Validation of Combustion in a Wood Pellet Boiler Using Computational Fluid Dynamics

In this study, combustion behaviour were to analyze by comparing experimental data against predicted values. In developing pellet boiler performance, various factors such as combustion chamber shape, input air velocity, the amount of fuel, temperature, and fuel characteristics need to be analyzed. Analytical model using a numerical method is useful to overcome time and cost consuming by practical experiment. By controlling feeding rate of fuel, flue gas composition and temperature distribution obtained form experiment were compared with predicted values using FLUENT(ANSYS, Inc., Southpointe). Measurement were in good agreement with model predictions : with 0.60 % for CO 2 0.73% for O 2 when compared with independent data sets.

Potential biomass supply for agro-pellet production from agricultural crop residue in Nepal

ABSTRACT Nepal, a country rich in biomass, still does not have any commercial pellet production plants and is wasting large amounts of agricultural crop residue. The current study showed that about 5.61 million tonnes (Mt) of biomass in the form of pellets are potentially available from agricultural crop residues. The brick and cement industries could use these agro-pellets. Co-firing of pellets in such industries could play an important role in reducing the import volume of coal and minimize the related environmental loadings.

A Study on Combustion Characteristics in terms of the Type of Fuel Supply Device (Feeder) of a Wood Pellet Boiler

This study reports the combustion characteristics, such as burner temperature and the concentration of exhausted gas (, , ) due to the different types and pitches of the fuel supply feeder of the wood pellet boiler. The 1st grade wood pellets composed of mainly larch have been used for the experiment. In case of using the spring feeder, mean temperature of burner was approximately , and the mean concentration of oxygen, carbon monoxide, carbon dioxide and nitrogen oxide were approximately 8.88%, 93.35ppm, 12.15% and 139.83 ppm, respectively. The test result with the spring feeder was shown to approach the condition of complete combustion compared to that of a screw feeder and were in good agreement with authentication judgement standard. Furthermore, the combustion efficiency was improved according to the growth of screw pitch. The control of air flow rate from the blower and ventilator is needed to achieve the complete combustion.