A small-scale fluidized bed was used to study the reactivity of Ni-based oxygen carriers under the reducing conditions (CH4 and CO+H2) at different reaction temperatures (650 ℃,750 ℃,850 ℃,950 ℃). The results reveal that nickel-based oxygen carriers have a high reactivity in both CH4 and CO+H2 atmospheres, and the reaction is more complete under the atmosphere of CO+H2. Furthermore, carbon deposition is found in both reduction processes, but it is more serious in CH4 atmosphere. In addition, the increase of temperature has a great influence on the reactivity of nickel-based oxygen carriers as well as the degree of carbon deposition, but it has less effect on the reduction reaction when the temperature exceeds 850 ℃. Also, nickel-based oxygen carriers have a better reactivity compared with copper-based oxygen carriers, but it is easier to produce carbon deposition during the reduction process.%采用小型流化床反应器,研究了Ni基载氧体在不同还原气氛(CH4、CO+H2)和不同反应温度(650℃、750℃、850℃、950℃)下的反应特性.结果表明:Ni基载氧体在两种气氛下均表现出较高的反应活性,CO+H2气氛下的还原反应比CH4气氛下的还原反应更完全,两个还原过程中均有积炭的产生,CH 4气氛下的积炭比CO+H2气氛下的积炭更为严重；在CH4气氛下,温度的升高有利于Ni基载氧体还原反应的进行,同时还原过程中产生的积炭量也随着温度的升高有所增加,但当温度升高到850℃后,温度的增加对还原反应的影响不大.另外,相比于Cu基载氧体,Ni基载氧体虽然有更好的反应活性,但在还原过程中更容易产生积炭.
展开▼
