焦油模型化合物与铁基氧载体的反应特性研究

Study on the reaction characteristics of tar model compounds with an Fe-based oxygen carrier

本研究以生物质/煤的焦油模型化合物(TMCs)为研究对象,在两阶段固定床实验上探究了铁基氧载体(70%Fe_(2)O_(3)/30%Al_(2)O_(3))对TMCs的转化特性,考察了不同TMCs的反应性及其转化的影响因素。研究发现,TMCs与氧载体的反应活性为:苯酚>蒽>萘,且苯酚转化生成积炭的比例最多(64%),而萘转化生成积炭的比例最少(40%);氧载体与萘的反应程度相对较高,但容易导致氧载体的烧结。此外,积炭表征显示萘生成的积炭在三种TMCs中具有最高的稳定性。增加氧载体的用量和提高反应温度不仅有利于萘和蒽的进一步转化,而且能够增加气相产物中CO_(2)的分率。由于苯酚分子具有较高的反应活性及较强的裂解效果导致其转化率随氧载体用量和反应温度的增加变化较小,然而,较高的反应温度(1000℃)导致焦油发生严重的裂解现象并产生大量积炭。三次循环实验结果表明与萘反应的氧载体失活最为严重。

This work investigated the conversion characteristics of iron-based oxygen carrier(70%Fe_(2)O_(3)/30%Al_(2)O_(3))with TMCs in a two-stage fixed-bed reactor using tar model compounds(TMCs)of biomass/coal,and evaluated the reactivity of different TMCs and the factors affecting their conversion.It was found that the reaction degree of TMCs with oxygen carrier was phenol>anthracene>naphthalene,and the conversion of phenol to carbon deposition was the highest(64%),while the conversion of naphthalene to carbon deposition was the lowest(40%);the degree of reaction between oxygen carriers and naphthalene was relatively high,but easily led to the sintering of oxygen carrier.Besides,activity characterization of the carbon deposition showed that the carbon deposition generated from naphthalene had the highest stability among the three TMCs.Increasing the amount of oxygen carrier and reaction temperature was beneficial to the further conversion of naphthalene and anthracene,and could also increase the fraction of CO_(2)in gaseous products.The high reaction activity and strong cracking effect of phenol led to a small change in the conversion rate with increasing the amount of oxygen carrier and reaction temperature.However,high reaction temperature(1000℃)could lead to severe cracking of the tar to generate a large amount of carbon deposition.The results of the cycle experiment showed that the oxygen carrier reacting with naphthalene was most severely deactivated.