| Summary: | 碩士 === 國立交通大學 === 產業安全與防災學程碩士班 === 90 === Abstract
The objective of this study is to evaluate the economical and environmental benefits of the down-draft rice husk gasifier for power generation system which applied in middle and large rice-hulling mills. The result shows that it is economically feasible . After havesting, the rice is transported to the Agricultural Association or rice-hulling mills for the processes of drying, milling, packing and selling. Hence, installing a rice husk gasifier for power generation system can recover the energy of rice husk and save waste treating and transportation fees. Besides the benefit of power generation, the by-product of husk ash is even more valuable.
Taking a 54 tons rice production plant in the Agricultural Association or rice-hulling mills for example, there are 10.8 tons rice husk produced for 24 hours operation per day, net power generation is 375,360 kw/year, the benefit of power is 750,720 NT＄/year. The quantity of husk ash is 540 tons/year, the benefit of husk ash is 3,240,000 NT＄/year, for 6,000 NT＄/ton. If rice husk is treated as a waste, the total treating fees will be 810,000 NT＄/year, for 300 NT＄/ton. Besides, the condensed liquid of the gasifier syn-gas, can be used as a fertilizer and pesticide, the quantity is 345.6 tons/year, and the benefit is 172,800 NT＄/year. Hence, the benefit of a rice husk gasifier for power generation system is 4,973,520 NT＄/year, after deducting the direct and indirect cost of compensation, interests, insurances, operation, maintenance, the net profit is 1,394,520 NT＄/year. The investment cost can be recovered in 2~3 years. According to estimation, 72.5 ﹪rice husk（about 290,191 tons/year）is collected by the Agricultural Association or middle and large rice-hulling mills, the total profits will be 239,246,355 NT＄/year.
The carbon source of biomass-energy is from the photosynthesis of the plant absorbing carbon dioxide. The utilization of carbon producing carbon dioxide which recycles to organisms for growing. There is no effect for the discharge of globe warming gases. Without considering the problems of waste treatment and by-product recovery, Applying rice husk combustion to generate energy can reduce emission of 1.0 kg carbon dioxide per 1kg utilization of rice husk, which reduces emission of 290,191 tons/year carbon dioxide. Comparing with the power generation by fuel oil or coal combustion, rice husk gasifier power generation can reduce 0.85kg CO2 emission per 1kw power, total amount of 64,486,888 kw generated reduces emission of 54,814 tons/year carbon dioxide. In addition, rice husk contains trace sulfur, it may reduce the emission of NOX and SO2 , and therefore there is an obvious benefit in environmental protection.
|
|---|
