| 摘要: | 摘要
本研究利用含浸硫酸鋅/硫酸亞鐵、硫酸鋅/硫酸銅與硫酸銅/硫酸亞鐵於椰殼製備成活性碳觸媒並應用於去除氮氧化物。研究中以比表面積分析(BET)、掃描式電子顯微與/X射線能量分散分析儀(SEM/EDS)、X射線繞射儀(XRD)分析活性碳觸媒之結構與化學特性， 利用TPD-O2與TPR-H2分析觸媒表面特性，並以選擇性觸媒還原法(SCR)與非選擇性觸媒還原法(NSCR)於不同溫度下探討還原氮氧化物之活性，由BET結果顯示，含浸量鋅越高所製備之活性碳皆具有良好表面特性及孔隙，其中含浸硫酸鋅/硫酸銅之碳觸媒具840 m2/g比表面積分析最高，相較其他金屬鹽比表面為高，而當含浸硫酸鋅時，比表面積隨著鋅的含量增加而增加，比表面積增加與TPD-O2成正相關，利用TPR-H2圖譜可發現，當銅與鐵的含量越多還原活性越好。選取最佳活性碳觸媒硫酸鋅/硫酸銅(0.02/0.08)，於非選擇性觸媒還原法(NSCR)，於600℃甲烷2000ppm、空間流速約5732 hr-1時能有效還原500ppmv氮氧化物，而選擇性觸媒還原法(SCR)於600℃時，氨1000ppm、空間流速約11464 hr-1時，500ppmv還原率可以達到99%，而比較NSCR與SCR反應後發現，氨(NH3)比甲烷(CH4)還原能力更強，而添加少量促進劑(O2) (2000- 6000 ppmv)於NSCR還原法中，對於一氧化氮(NO)的還原效果並沒有很大的幫助，當加入促進劑(O2)還原率大約80%，而沒有加入促進劑(O2)時，還原率約在87%，在觸媒於SCR還原法中，當促進劑(O2)添加量為500與1000 ppm時，其還原效果可提升到99%，且還原溫度也提前至500℃，這顯示出添加少量之O2能使硫酸鋅/硫酸銅觸媒活性增加。
Abstract
In this investigation, the activated catalyst were prepared with Zinc sulfate/Iron (II) sulfate, Zinc sulfate/ Copper(II)sulfate, Copper(II)sulfate/ Iron (II) sulfate and they wereapplied for NOx reduction. Thephysical and chemicalcharacteristics of carbon catalyst were analyzed by BET，SEM/EDS，and XRD. The activity of oxidation and reduction of carbon catalyst were quantified by the TPD-O2 and TPD-H2 analysis. In this investigation, the selective catalytic reduction (SCR) andnonselective catalytic reduction (NSCR) were carried out to converse the NOx with various carbon catalyst. Based on the N2 adsorption analysis, the Zinc content in catalyst enhanced the pore development and enlarge the surface area, such as the Zn/Cu catalyst own a 840 m2/g surface area , and the increase in Zinc content increased the surface area of catalyst. On the other hand, the surface area of catalyst is proportional to the TPD-O2 of catalyst. The Cu/Fe catalyst presented a good activity of reduction in SCR and NSCR. The almost completely conversion of NOx can beachieved with Zn/Cu(2/8) at the 5732 hr-1 space velocity, 600℃ under2000 CH4 or 1000ppm NH3 in reduction. It was also found that NH3 ismore effectively to reduction NOx than CH4 in catalytic reduction. Butthe enhancer, oxygen, did not contribute the significant effect on thereduction of NOx in SCR or NSCR. It is indicated that the slightenhancement on the reduction can be observed with O2 inreduction inSCR. Finally, it is confirmed that the Zn/Cu, Zn/Fe, and Cu/Fe presented the highly activity on the reduction of NOx in SCR or NSCR.
Key words: Reduction, NOx, TPD-O2, TPR-H2, selective catalyticreduction(SCR), nonselective catalytic reduction(NSCR) |
