Plasmatron Gasification of Raw and Torrefied Japanese Cryptomeria under Different Agents

• Main Authors: Yang, Yi-Fan, 楊逸凡
• Other Authors: Shie, Je-Lueng
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/65606660679676758980

碩士 === 國立宜蘭大學 === 環境工程學系碩士班 === 101 === Torrefaction is a method to pre-treat biomass before its’transportation or thermochemical conversion. It can be used to increase the energy content of biomass or to facilitate their Hardgrove grindability index (HGI) for sutiable to mix with coal powder in combustion. This work is to study the feasibility and operational performance of plasmatron (thermal plasma) gasification of torrefied Japanese Cryptomeria (TC) and Japanese Cryptomeria waste (CW), as the target sample materials. A 10 kW plasmatron reactor was used for the gasification of the samples. The temperature of the plasmatron reactor was controlled at 873 K. From proximate analysis results, torrefaction can enhance the percentage of volatile matter and ash. In the elemental analysis, the carbon contents in residues of TC and CW increased from 57.79 and 48.42 wt. % to 90.84 and 67.74 wt. %, respectively. After plasmatron gasification, the higher heating value (HHV) of residues increased to 1.28-1.3 times of samples and its maximum value reached to 7391 kcal/kg. Furthermore, the syngas yield of TC increased from 43.77 to 76.44 wt. % and the residue decreased from 18.7 to 6.4 wt. % after the steam injection. Therefore, Water-gas shift reaction and Coke combustion reaction take place prefer as TC than CW clearly at the steam circumstance. Using CO2 as the gasification agent, H decreased obviously, and it shows that H was released after CO2 injection. The yield of combustible gas (CO+H2+CH4) of TC can increase to 109.05 wt. %, better than CW of 98.71 wt. % at the CO2 circumstance. The conversion efficiency of input CO2 can reach to 58.05%. Under CO2 condition, Boudouard reaction and Water gas reaction both take place obviously. Moreover, co-injection of steam and CO2 as the gasification agents, the conversion efficiency of input CO2 increase from 58.05 to 61.14%, and carbon conversion can be up to 99.44 wt. %, residue content decreased to 2.43 wt. %, all data show that biomass and steam and CO2 co-torrefaction after steam and CO2 gasification in a plasmatron reactor will enhance the syngas yields and thermal conversion completely. Therefore, co-gasification of torrefaction biomass with wet greenhouse gas (GHG) is a key technique for the plasmatron thermal conversion system. In the near future, co-treatment of carbon waste with GHG will become a potential new technology.