Redox reforming based, integrated solar-natural gas plants: Reforming and thermodynamic cycle efficiency

Abstract

As demand for energy continues to rise, the concern over the increase in emissions grows, prompting much interest in using renewable energy resources such as solar energy. However, there are numerous issues with using solar energy including intermittancy and the need for storage. A potential solution is the concept of hybrid solar-fossil fuel power generation. Previous work has shown that utilizing solar reforming in conventional power cycles has higher performance compared to other integration methods. Most previous studies have focused on steam or dry reforming and on specific component analysis rather than a systems level analysis. In this article, a system analysis of a hybrid cycle utilizing redox reforming is presented.Important cycle design and operation parameters such as the oxidation temperature and reformer operating pressure are identified and their effect on both the reformer and cycle performance is discussed. Simulation results show that increasing oxidation temperature can improve reformer and cycle efficiency. Also shown is that increasing the amount of reforming water leads to a higher reformer efficiency, but can be detrimental to cycle efficiency depending on how the reforming water is utilized.

Dry redox reforming hybrid power cycle: Performance analysis and comparison to steam redox reforming

“…The iron/magnetite pair will be used for the redox reformer cycle analysis done herein. Note that the oxidation reaction with CO 2 is slightly endothermic which is different from oxidation with steam which is exothermic [18].…”

“…Basically, a chemical looping process is created. From previous system analysis of a redox reforming hybrid cycle, iron/magnetite was shown to be a promising metal/metal oxide pair for solar redox reforming due to its required temperatures for the reactions, oxygen carrying capacity, and material costs [18]. The iron/magnetite pair will be used for the redox reformer cycle analysis done herein.…”

“…For comparison, the iron oxidation results are plotted with the steam oxidation results obtained from [18]. atures, which is important as the operating temperatures are likely to be higher in order for the reactions to proceed at a reasonable rate [18].…”

“…The hybrid power cycle used in this analysis is similar to the one used in [18] and consists of The CO 2 for reforming is assumed to be readily available. The implementation of the solar collector system with the two reactors is similar to the one presented in [18] in that the solar application is modeled as a heat source. Since, as discussed previously, the oxidation of Fe with CO 2 is endothermic, both the oxidation and reduction reactor utilizes the solar energy.…”

“…System level studies have also been performed for steam and redox reformer hybrid cycles [2,3,18]. Specifically for the redox reformer hybrid cycle, the previous analysis done was for a reformer utilizing steam in the oxidation step [18].…”