| Summary: | 碩士 === 國立中央大學 === 能源工程研究所 === 105 === The research can be discussed in two aspects, including fluidizing condition-liquid yield and pyrolysis condition-chemical analysis.
Firstly, the main factor that affects minimum fluidizing velocity (umf) is particle size. When gas velocity falls on 2.33 umf, average oil yield is about 20wt.% which is better than other values, and the pH value is higher, which means bio-oil is hard to second-react with acidic matters in it. Temperature doesn’t have many things to do with fluidizing pressure drop as the value of each size keeps the same; When particle size falls on 0.40mm, there is the best yield of all, 32.18 wt.%. And carbon conversion rate is also higher as acidity is weaker. C, H, O three elements take the majority in bio-oil. For C, is about 20wt.%, for H, is about 10-15wt.%, for the rest part is O as N and S are very few.
Secondly, at 500℃, there are higher oil-yield of 23wt%-32wt%, and so as HHV, the best one is 7254.1kcal/kg. And acidity is weaker while conversion rate is better. For the reason that TGA analysis models of biomass in heating mode have been set up by some researchers while isothermal mode haven’t and needs shorter time to reach steady temperature, this research use isothermal mode to test the thermal-gravimetric loss of biomass observe the properties of pyrolysis, and calculate the pyrolysis dynamic parameters. The chemicals that have apparent area concentration in bio-oil are Acetic anhydride, 1,2-benzenediol, 2-methylphenol and phenol.
Finally, consider those correlation coefficients, the fluidizing pressure drops are negatively related to oil yields. When pressure drops get smaller, closer to 2 umf, the oil yields get higher, which means that the minimum bubbling velocity, umb, is quite close to 2umf ; In chemicals contained in the oil, 2-hydroxyl-3-methyl-2-cyclopenten-1-one is dominant in carbon content, HHV and pH value, and is positively related to them; Meanwhile, acetic anhydride and toluene are negatively related to carbon content, HHV, carbon conversion rate; 4-methylphenol is highly positively related to carbon conversion rate.
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