作为一种可实现CO2内分离的新型燃烧方式，氧气解耦的化学链燃烧（chemical looping with oxygen uncoupling, CLOU）因其相对于燃烧前捕集、富氧燃烧、燃烧后捕集具有低成本捕集CO2的优势而受到广泛关注。载氧体是CLOU过程的关键，本文针对铜基载氧体，开展了人工载氧体制备、改性与筛选，流化床释氧及燃烧性能测试，以及天然铜矿石作为载氧体的可行性三个方面的研究。 在人工载氧体制备与筛选方面，在热力学分析基础上，利用热重分析仪对载氧体释氧和吸氧的特性进行测试，考察SO2和NO对载氧体的影响。采用浸渍法制备载氧体颗粒，通过更改惰性载体类型及制备复合载氧体两种方法来改善其释氧/吸氧循环稳定性。研究结果表明，铜基的熔点低，在高温下烧结严重而导致载氧量衰减，添加钴、镁、镍、锶四种金属氧化物可以抑制烧结。 利用小型流化床反应器研究了铜镍、铜镁两种复合载氧体的循环释氧/吸氧特性，发现三次浸渍的复合载氧体极易在流化床中发生团聚，增大流化风速和减少浸渍量可以减弱或避免团聚。考察了H2S、CO、褐煤及石油焦与铜基载氧体的反应特性。随着温度升高，载氧体被CO还原的程度增大。褐煤的挥发份含量高，挥发份和气化产物与载氧体的反应占有较大比重；而石油焦的固定碳含量高，反应时需要利用载氧体释放的氧气。 利用热重分析仪和小型流化床反应器，对湖北大冶铜矿三种成分不同的铜矿石进行了测试，实验结果表明天然铜矿石循环稳定性良好，煅烧后CuO含量5.82%的铜矿石颗粒在流化床中不易团聚，固体燃料的燃烧效果与人工合成载氧体相似，证明铜含量适宜的铜矿石具备作为载氧体的潜力。
As a new technology with inherent CO2 separation, the process of chemical looping with oxygen uncoupling (CLOU) has been paid more attention, due to its potential economics comparing to the pre-combustion, oxyfuel combustion and post-combustion CCS technologies. Because the oxygen carrier is the key to CLOU process, three different aspects on the Cu-based oxygen carrier were investigated, including carrier preparation, modification and selection, fluidized-bed testing of oxygen release/absorption performance, and the feasibility of using natural copper ore as oxygen carrier. For carrier preparation and selection, the thermodynamic analysis of Cu-based oxygen carrier was carried out, and the oxygen release and absorption characteristics and the influence of SO2 and NO were studied using thermal-gravimetric analyzer. Carrier particles were prepared by impregnation and two modification methods were tested to improve the stability of oxygen release/absorption multi-cycle reactions, including different types of inert carriers and double metal oxide carriers. The results showed that the low melting point of copper oxide and high operating temperature caused a serious sintering problem which lead to an attenuation of oxygen capacity, and the sintering can be prohibited by adding cobalt, magnesium, nickel or strontium oxides during the carrier preparation and in that case the stability of oxygen carrier was improved. The cyclic oxygen release/absorption characteristics of selected Cu-Mg and Cu-Ni double metal oxide carriers were investigated with a small fluidized bed reactor. The pollutant influence of H2S, combustion reactivity with CO as gas fuel, and lignite and petroleum coke as solid fuel were studied. It was found that oxygen carrier prepared with more impregnation was more likely to agglomerate in the fluidized bed and both increasing the gas flow and reducing the amount of copper oxide can solve the problem. As the temperature increased, the reduction extent by CO of oxygen carrier increased. For the high volatile content of lignite, the gas combustion of volatile and gasification products played an important role, while the combustion between carriers and petroleum coke depended on the oxygen released for the high carbon content of petroleum coke. Three copper ore samples with different composition from Daye in Hubei province were tested on TGA and a small fluidized bed reactor, and all of them showed good cyclic stability. The sample with lowest 5.82% CuO content after calcination did not agglomerate in fluidized bed and the combustion result of solid fuel was similar to the artificial double metal oxide oxygen carriers, which illustrated that the copper ore with suitable copper oxide content had a potential to be used as oxygen carrier.
