Preparation of Composite Ni-Fe Oxide as Oxygen Carrier for Chemical Looping Combustion Process

• Main Authors: Jia-long Ma, 馬嘉隆
• Other Authors: Yao-Hsuan Tseng
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/31135422462134841768

碩士 === 國立臺灣科技大學 === 化學工程系 === 99 === In this research, a highly active oxygen carrier for chemical looping combustion (CLC) process was developed with using nickel and iron nitrate as precursors, respectively. Effects of the preparation variables on the oxidation and reduction activities of composite oxygen carriers were systematically examined using the fractional factorial design (FFD). The following preparation parameters were investigated in the present FFD analysis: amount of water, calcination temperature, amount of dispersant, amount of nickel nitrate, and amount of iron nitrate. Sixteen kinds of Ni-Fe composite oxygen carrier were prepared by sol-gel method according to the preparative conditions of FFD. Reactivities of oxygen carrier were evaluated in a thermogravimetric analyzer (TGA). The effects of the preparation parameters on the structure, and physicochemical properties of the composite oxygen carriers were elucidated by X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), and Brunarer-Emmett-Teller (BET) adsorption. The most active sample was obtained under these conditions: 0.01 mol of Ni(NO3)2, 0.03 mol of Fe(NO3)3, 3 g of PEG, 15 mL of water, and calcination at 1000°C for 6 h. The analysis of variance table (ANOVA) indicate the effect of amount of nickel nitrate is the key factors influencing the redox activity of composite oxygen carrier. According to the results, the optimal amount of Ni/Fe molar ratio, 5, was further found to obtain an oxygen carrier with high reduction and oxidation activities. The agglomeration of oxygen carrier resulted in the decrease of activity. After the immobilization of composite oxygen carrier on a porous ceramic filter, the thermal stability of oxygen carrier was enhanced greatly and could be used in CLC process practicably.