| Summary: | 碩士 === 國立中興大學 === 森林學系所 === 105 === Co-torrefaction of paper mill sludge and Cryptomeria japonica was conducted in this study. The operating conditions for the torrefaction temperature and residence time were set as 250, 300, 350 and 400℃, and 20, 40 and 60 minutes, respectively. Torrefaction products can be classified into solid, liquid and gas. The characteristics of solid torrefied biomass such as ultimate, proximate, mass yield, heating value, energy yield, Hardgrove Grindability Index (HGI) and heavy metal analyses were investigated. In addition, the yield and composition of torrefied liquid and gas were also analyzed.
The results show that the heating value, fixed carbon and ash content of torrefied biomass of mixed paper mill sludge and Cryptomeria japonica increased with increasing the torrefaction temperature and residence time, but the moisture, volatile matter, nitrogen, hydrogen, oxygen and sulfur contents shows the contrary results. In addition, the HGI of mixed paper mill sludge and Cryptomeria japonica was greatly improved by about 6.3 times after torrefaction. According to the van Krevelen’s diagram, the characteristics of torrefied biomass of mixed paper mill sludge and Cryptomeria japonica is similar to coal. It is more suitable as the fuel for the PC boiler.
Moreover, the yield of torrefied liquid and gaseous products increased with increasing the torrefaction temperature. For acid-based substances, acetic acid was from torrefaction of Cryptomeria japonica, and other fatty acid was from torrefaction of sludge. For phenolic substances, torrefied liquid from Cryptomeria japonica contains o-methoxyphenol and 4-ethyl-2-methoxyphenol mainly, and that from paper mill sludge contains o-methoxyphenol only. On other hard, the composition of the torrefied gaseous is CO, CO2, CH4 and CnHm. CO, CO2 and CH4 increased with increasing the torrefaction temperature and residence time. In addition, Observe the torrefied gas composition of sludge and cedar mixture ratio 50:50. It can be found that, when the torrefaction temperature is higher than 300℃, the CnHm content increased from co-torrefaction of paper mill sludge and Cryptomeria japonica with mixed ratio of 50%. It is suggested that the metal content of the paper mill sludge could act as the catalyst to produce the more than C2 compound molecules.
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