Chemical-looping with oxygen uncoupling using CuO/ZrO2 with petroleum coke

Artikel i vetenskaplig tidskrift, 2009

Oxygen carrier particles of CuO/ZrO2 were reacted with petroleum coke using chemical-looping with oxy- 24 gen uncoupling (CLOU). The fuel was burnt in gas-phase oxygen released from the oxygen carrier parti- 25 cles during the fuel oxidation. The particles were then regenerated in 5–21% oxygen. In this process, the 26 carbon dioxide from the combustion is inherently separated from the rest of the flue gases without the 27 need for an energy intensive air separation unit. Copper oxide has thermodynamic characteristics that 28 make it suitable as an oxygen carrier in CLOU. Particles were prepared by freeze granulation and were 29 exposed cyclically with petroleum coke and oxygen in a laboratory fluidized bed reactor of quartz. The 30 reaction temperature and oxygen concentration during the oxidation were varied. The average conver- 31 sion rate of petroleum coke was a function of temperature and varied between 0.5%/s and 5%/s in the 32 set-point temperature interval 885–985°C. The conversion rate is considerably higher than rates 33 obtained with the same fuel using iron-based oxygen-carrier in chemical-looping combustion. As for 34 the regeneration with oxygen, the reduced particles reacted at low oxygen concentrations, with a consid- 35 erable part of the reaction occurring near the thermodynamic equilibrium.