Performance of a Cu–Fe‐based oxygen carrier combined with a Ni‐based oxygen carrier in a chemical‐looping combustion process based on fixed‐bed reactors

Abstract

The application of chemical‐looping combustion (CLC) based on fixed‐bed reactors for distributed medium‐ and small‐scale hot‐water and steam gas‐fuelled boilers is promising due to its low NOx emission, high energy efficiency and nearly zero energy consumption in carbon capture. For fixed‐bed reactors, a wide operating temperature window (Tw) for the oxygen carrier (OC) is crucial to ensure the performance and cycle life of the OC. The performance of Cu30–Fe50/Al20‐M combined with different Ni‐based OCs was investigated to extend the Tw(L) of 600°C for Cu30–Fe50/Al20‐M to a lower temperature, which was developed previously. The different Ni‐based OCs would work as CH4 steam reforming catalysts if their required reduction temperatures were significantly lower than the Tw(L) of Cu30–Fe50/Al20‐M. Results showed that a Ni‐based OC of Ni60/Al40‐M could be reduced with CH4/H2O with an S/C of 1.0 at a temperature of 450°C. The combination of Cu30–Fe50/Al20 and Ni25/Al75‐I, which was packed in the bed by a mixing method, exhibited a low‐temperature reactivity and Tw(L) was lowered from 600°C to 490°C. Moreover, carbon deposition and an intermediate compound, NiFe2O4, which was found in a composite OC of Ni–Cu–Fe–/Al, were not detected during the reduction step. Based on the results, a new CLC process, which was characterised by an integrated methane steam reforming in the reduction step, was proposed. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.

Chemical Looping Combustion: A Brief Overview

“…The authors believe that this improvement results from more efficient gas-solid mass transfer due to the reduced bubble size. Detailed results from experimental tests on fixed bed reactors are reported in [105][106][107][108][109][110].…”

Advanced Chemical Looping Materials for CO2 Utilization: A Review

“…It was also found that the introduction of a NiO-based oxygen carrier into the Fe 2 O 3 /CuO-based oxygen carrier bed facilitated the reduction of the operating temperature in CLC process, due to the high reactivity of Ni towards CH 4 . Further, a layer-by-layer mixing mode of a NiO-based oxygen carrier and a Fe 2 O 3 /CuO-based oxygen carrier in a fixed-bed reactor avoids the formation of NiFe 2 O 4 spinel during the reduction half-cycle, ensuring a good redox rate, thereby providing a promising reactor configuration candidate for an enhanced-CH 4 -reforming chemical looping process [132]. …”