【摘要】：固體廢棄物熱解氣化是固體廢棄物高值化利用的轉(zhuǎn)化方法。將固體廢棄物熱解氣進(jìn)行甲烷化反應(yīng)制備合成天然氣不僅可以減緩對(duì)目前天然氣的需求,并且可以提高熱解氣利用率。固體廢棄物熱解的不可凝氣體產(chǎn)物一般是在常壓下輸出的,若將輸出的氣體直接在常壓下繼續(xù)進(jìn)行甲烷化反應(yīng)制備合成天然氣,便不用再對(duì)系統(tǒng)或是合成氣加壓,這樣可以節(jié)約運(yùn)營成本,節(jié)省能源。因此,目前需要對(duì)常壓下甲烷化的工藝條件及甲烷化催化劑需要進(jìn)行更進(jìn)一步的研究,以期開發(fā)經(jīng)濟(jì)高效的常壓甲烷化催化劑可以直接與之耦合。本文首先采用γ-Al2O3為載體,用等體積浸漬法,制備了一系列Ni-Fe/Al2O3甲烷化催化劑。實(shí)驗(yàn)結(jié)果表明,常壓下,反應(yīng)空速在30000 mL/(g·h)-450000 mL/(g·h)范圍內(nèi),反應(yīng)溫度在230℃C-330℃C范圍內(nèi)進(jìn)行甲烷化反應(yīng)最佳。Fe的引入,使得Ni-Fe/y-Al2O3雙金屬催化劑表現(xiàn)出高的甲烷化活性,CO的轉(zhuǎn)化率接近100%,CH4的選擇性可達(dá)90%以上。在Ni和Fe的負(fù)載量均在15%的情況下,催化劑催化效果達(dá)到最佳。BET、XRD及H2-TPR分析表明,Ni-Fe/γ-Al2O3雙金屬催化劑中Ni、Fe之間產(chǎn)生了明顯的相互作用,鐵助劑的添加可減少了鎳鋁尖晶石NiAl2O4的生成,也就增加了游離態(tài)的NiO,使催化劑的還原溫度降低,NiO的分散度有所提高,提高了催化劑活性。接著進(jìn)行了15Ni-15Fe/γ-Al2O3催化劑的壽命測試,發(fā)現(xiàn)在15Ni-15Fe/y-Al2O3催化劑的壽命12-15 h左右。隨后采用沉淀、共沉淀、溶膠凝膠法三種不同的制備方法制備TiO2-Al2O3為復(fù)合載體,制備了一系列15Ni-15Fe/TiO2-Al2O3甲烷化催化劑,為了研究Ti02的添加與制備方法對(duì)催化劑甲烷化活性與壽命的影響。實(shí)驗(yàn)結(jié)果表明,添加Ti02之后可以使15Ni-15Fe/y-Al2O3催化劑具有更寬的甲烷化適宜溫度范圍。溶膠凝膠法制備的15Ni-15Fe/TiO2-Al2O3催化劑的甲烷化活性最高。Ti02的添加增加了15Ni-15Fe/y-Al2O3催化劑的抗積碳的能力。BET、XRD、TEM及H2-TPR分析表明,載體中加入部分Ti02可削弱γ-Al2O3與NiO的相互作用,也就是減少了鎳鋁尖晶石NiAl2O4的生成,可使NiO晶粒細(xì)化,增加NiO晶粒在載體γ-Al2O3表面上的分散。溶膠凝膠法制備的15Ni-15Fe/TiO2-Al2O3催化劑的活性組分NiO的分散程度最高,達(dá)到納米級(jí),催化活性最好,并且穩(wěn)定性好,有最強(qiáng)的抗積碳能力。接著進(jìn)行了三種15Ni-15Fe/TiO2-Al2O3催化劑的壽命測試,溶膠凝膠法制備的15Ni-15Fe/TiO2-Al2O3催化劑的壽命最長。最后本文采用Powell(PO)優(yōu)化方法,建立了催化劑甲烷化宏觀動(dòng)力學(xué)模型,利用Aspen Plus軟件進(jìn)行了甲烷化流程模擬,通過甲烷化的過程模擬對(duì)催化劑的甲烷化宏觀動(dòng)力學(xué)模型進(jìn)行了進(jìn)一步的驗(yàn)證,15Ni-15Fe/TiO2-Al2O3催化劑對(duì)CH4的選擇性更高,并且15Ni-15Fe/TiO2-Al2O3催化劑的甲烷化反應(yīng)更加迅速。
[Abstract]:Pyrolysis and gasification of solid waste is a conversion method for high value utilization of solid waste. The methanation reaction of solid waste pyrolysis gas to synthetic natural gas can not only slow down the demand for natural gas but also improve the utilization ratio of pyrolysis gas. The non-condensable gas products of solid waste pyrolysis are generally exported under atmospheric pressure. If the exported gas continues to methanize directly under normal pressure to produce synthetic natural gas, there is no need to pressurize the system or syngas. This can save operating costs, save energy. Therefore, it is necessary to further study the process conditions of methanation under atmospheric pressure and the methanation catalyst in order to develop an economical and efficient atmospheric methanation catalyst that can be directly coupled with it. In this paper, a series of Ni-Fe/Al2O3 methanation catalysts were prepared by using 緯-Al2O3 as carrier and isobaric impregnation method. The experimental results show that under atmospheric pressure, the reaction space velocity ranges from 30000 mL/ (g h) to 450000 mL/ (g h), and the reaction temperature is in the range of 230 鈩，

本文編號(hào)：2332820