• Journal of Energy Engineering
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• v.24 no.2
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• pp.120-128
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• 2015

This study reports the combustion characteristics, such as burner temperature and the concentration of exhausted gas ($O_2$, $CO_x$, $NO_x$) 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 $821.76^{\circ}C$, 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.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.203-210
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• 2014

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.

• Proceedings of the Korea Forestry Energy Research Society Conference
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• 2011.02a
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• pp.88-89
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• 2011

• Journal of the Korean Wood Science and Technology
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• v.46 no.5
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• pp.597-609
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• 2018

Korea Forest Service has supplied 76 industrial wood pellet boilers from 2011 to 2015 through subsidy programs. Since carbon monoxide (CO) and nitrogen oxides ($NO_x$) generated during boiler combustion are substances that lead to death in the case of acute poisoning, it is very important to reduce emissions. Therefore, the CO and $NO_x$ emission values of 63 boilers excluding the hot air blower and some boilers initially supplied were analyzed. The emission factor was also calculated from the measured exhaust gas concentration (based on exhaust gas $O_2$ concentration of 12%). The average value of CO emitted from industrial wood pellet boilers was 49 ppm and it was confirmed that the CO concentration was decreasing as the years passed. The emission factor of CO was 0.73 g/kg. The average value of $NO_x$ emitted from industrial wood pellet boilers was 67 ppm and the emission factor of $NO_x$ was 1.63 g/kg. Unlike CO, there was no tendency to decrease according to the installation year. Both CO and $NO_x$ measurements met the limits of the Ministry of Environment. These $NO_x$ emission factors were compared with the $NO_x$ emission factors produced by certified low $NO_x$ burners. The $NO_x$ emission factor of industrial wood pellet boilers was about 1.9 times that of certified low $NO_x$ LNG combustors and about 0.92 times that of coal combustion.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.4
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• pp.403-410
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• 2017

With the growing importance of GHG reduction, wood pellets are considered as a cheaper renewable energy and carbon neutral. On the other hand, there is a concern that the burning wood pellets may release even more air pollutants such as CO and VOCs. In this study, we analyzed the social costs of burning fuels including wood pellets and coals based on the unit calorific value. The social costs were calculated by sum of the import costs of the fuels and the emission costs of the air pollutants. The results showed that wood pellets are inferior to coals in the aspect of the social costs. It is necessary to improve the quality of the wood pellets and pellet boiler facilities for being used eco-friendly energy sources in the future. We suggest that the control facilities of CO and VOCs should be installed, if the control costs are lower than the pollution costs.

• KIEAE Journal
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• v.15 no.1
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• pp.103-109
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• 2015

Recently, the usage of renewable energy system has been recommended because of the energy saving and depletion of fossil fuel. Especially, ground source heat pump system(GSHP) has a high efficiency by using annual stable ground temperature. Also, wood pellet is low cost and a high calorific value compared to fossil fuel. However, only small number of farms have applied renewable energy system to horticultural facility because of a high initial costs and uncertainty of its cost efficiency. In this study, in order to analyze the feasibility for the horticulture, TRNSYS simulation based on the standard horticultural facility was conducted in different weather and covering material conditions. Then, comparative feasibility analysis of each energy supplying system was conducted. As a result, we have found out that a high initial cost of renewable energy system was recovered by the economics of the energy cost. Due to the energy cost reduction, the payback periods were 10-11 years in the case of GSHP and 4-6 years in the case of wood pellet boiler.

• Journal of the Korean Society of Combustion
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• v.23 no.1
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• pp.44-54
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• 2018

Heat and mass balance process modeling has been conducted for a coal-firing power plant to be used as a testbed facility for development of various plant systems and equipment. As the material and design of the boiler tube bundle and fuel conversion to the biomass have become major concerns, the process modeling is required to incorporate those features in its calculation. The simulation cases for two different generation load show the satisfying results compared to the operational data from the actual system. Based on the established process conditions, the hypothetical case using wood pellet has also been simulated. Additional calculations for the tube bundle has been conducted regarding the changes in the tube material and design.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.19-20
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• 2013

The cofiring of renewable fuel in coal fired boilers is an attractive option to mitigate $CO_2$ emissions, since it is relatively low cost option for efficiently converting renewable fuel to electricity by adding biomass as partial substitute of coal. However, it would lead to reduce plant efficiency and flexibility in operation, and increase operation cost and capital cost associated with renewable fuels handling and firing equipment. The aim of this study is to investigate reduction of carbon dioxide at varying percentage of biomass in fuel blend to the boiler biomass, and estimate operation and capital cost. Wood pellet, PKS (palm kernel shell), EFB (empty fruit bunch) and sludge are considered as a renewable fuels for a cofiring with coal. Several approaches by the cofiring ratio are chosen from past plant demonstrations and commercial cofiring operation, and they are evaluated and discussed for CO2 reduction and cost estimation.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.32-42
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• 2012

Wood biomass including forest residues, waste wood, and construction residuals has been widely generated in Korea, but forest biomass from the National Forest Management Operation Project plays a big role in generating wood biomass. Unfortunately the promotion policy of woody energy organized by the Forest Service in Korea concentrates more on demand creation rather than on supply expansion. Therefore, in order to utilize insufficient wood resources effectively, it is greatly required to develop uses for maximizing their added value. In particular, more attention to the use of the second generation biomass has been paid in foreign countries because there is a threshold that the first generation biomass cannot produce enough biofuel without threatening food supplies and biodiversity. In Korea, wood pellets are regarded as the alternative clean fuels to oils and coals that emit green house gases into the atmosphere. However, using wood as pellet raw materials can not be an economic way because the value of wood disappears right after burning in the boiler in spite of its contribution to the decrease of carbon emission. Differently from wood pellets, kraft pulping process using woody biomass produces black liquor as a by-product which can be used to generate electricity, bioenergy and biochemicals through gasification. Thus, it can be more economical to make a torrefaction of lignocellulosic biomass such as low-quality wood and agricultural leftovers as raw materials of pellets.

• Plant Journal
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• v.18 no.3
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• pp.52-61
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• 2022

This study tested the effect of de-NOx Facility operating condition on Nox emisiion in a 125 MW wood pellet power plant in Yeongdong Eco Power Plant Unit 1, which is in operation. As SNCR urea flow rate increased, NOx emission gradually decreased, but ammonia slip after SCR increased. The boiler under test has a structure that is unfavorable to SNCR operation due to the high internal temperature, and the optimum location of the nozzle will be required. SCR dilution air temperature change did not affect the amount of NOx generated. Increasing SCR ammonia flow reduced the NOx emission at SCR outlet and also increased the NOx removal efficiency. However, the ammonia flow rate of 111 kg/h, which does not exceed the ammonia slip its own reference limit, is estimated to be the maximum operating standard. The increase in SCR mixer pressure reduced NOx emission and the removal efficiency was also measured to be the most effective variable to inhibit NOx production.