【摘要】：作為煤制天然氣的核心技術(shù)之一,CO甲烷化工藝的開(kāi)發(fā)基礎(chǔ)便是高效催化劑的研制.目前,CO甲烷化催化劑主要采用Ni作為活性組分,但如何保持其具有較高的催化活性和優(yōu)異的高溫穩(wěn)定性,仍為當(dāng)今不得不面臨的棘手問(wèn)題.本文以乙二醇改性的三維介孔KIT-6為載體,利用其較高的比表面積、可調(diào)孔徑、獨(dú)特的雙螺旋三維孔道結(jié)構(gòu)等特點(diǎn),通過(guò)濕式浸漬法成功制備了由助劑改性的Ni基催化劑,探討了V,Ce,La,Mn等不同助劑對(duì)Ni基催化劑CO甲烷化催化性能的影響.分別采用X射線衍射、氫氣程序升溫還原、氫氣程序升溫脫附、傅里葉變換紅外光譜、透射電子顯微鏡、能量色散X射線光譜、激光拉曼光譜和熱重分析等手段對(duì)催化劑特性進(jìn)行了表征.結(jié)果顯示,Ni-V/KIT-6具有最高的Ni納米粒子分散性(26.5%)和催化還原性,產(chǎn)生了最多的活性位,同時(shí),Si O V的形成增強(qiáng)了金屬-載體間相互作用,并因載體的三維介孔限制效應(yīng)而形成較小Ni納米粒子,這些均有助于提升Ni基催化劑CO甲烷化的催化性能和穩(wěn)定性.在常壓、250 400 ℃和60000mL/(g?h)空速的實(shí)驗(yàn)條件下對(duì)催化劑進(jìn)行了催化活性評(píng)價(jià)測(cè)試.結(jié)果表明,助劑提高了CO甲烷化低溫催化活性,其中,Ni-V/KIT-6在350 ℃的條件下實(shí)現(xiàn)了CO的完全轉(zhuǎn)化,CH_4產(chǎn)率也高達(dá)85%;其在常壓、500 ℃和60000 mL/(g?h)空速的操作條件下所進(jìn)行的穩(wěn)定性測(cè)試結(jié)果還顯示,Ni-V/KIT-6也具有優(yōu)異的抗燒結(jié)和抗積碳能力,展示了良好的高溫穩(wěn)定性.因此,Ni-V/KIT-6是一種具有廣闊應(yīng)用前景的CO甲烷化催化劑.
[Abstract]:As one of the core technologies of coal to produce natural gas, the development of CO methanation process is based on the development of high efficient catalyst. At present, CO methanation catalyst mainly uses Ni as active component, but how to maintain its high catalytic activity and excellent high temperature stability is still a thorny problem. In this paper, using ethylene glycol modified three-dimensional mesoporous KIT-6 as the carrier, using its high specific surface area, adjustable pore size and unique double helix three-dimensional pore structure, the Ni based catalyst modified by additives was successfully prepared by wet impregnation method. The effect of different promoters, such as V _ 2O _ ce _ La _ 2O _ mn and so on, on the catalytic performance of Ni based catalyst CO for methanation was investigated. X-ray diffraction, hydrogen temperature-programmed reduction, hydrogen temperature-programmed desorption, Fourier transform infrared spectroscopy, transmission electron microscope, energy dispersive X-ray spectroscopy, The characteristics of the catalyst were characterized by laser Raman spectroscopy and thermogravimetric analysis. The results show that Ni-V/KIT-6 has the highest dispersion of Ni nanoparticles (26.5%) and catalytic reduction, resulting in the most active sites. At the same time, the formation of Si O OV enhances the metal-carrier interaction. Smaller Ni nanoparticles were formed due to the three-dimensional mesoporous confinement effect of the support, which is helpful to improve the catalytic performance and stability of Ni based catalyst CO methanation. The catalytic activity of the catalyst was evaluated under the conditions of atmospheric pressure, 250,400 鈩，

本文編號(hào)：2406808