Yilmaz Duygu, Steenari Britt-Marie, Leion Henrik
Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden.
ACS Omega. 2021 Jun 16;6(25):16649-16660. doi: 10.1021/acsomega.1c02138. eCollection 2021 Jun 29.
Chemical looping combustion (CLC) is one of the most promising methods for carbon capture and storage (CCS). An oxygen carrier, i.e., a mineral that can be oxidized and reduced, is used to convert the fuel in the process. The produced CO is inherently separated from the air components that enables easier CCS. The use of biomass-based fuels is desirable since it can lead to negative CO emissions. On the other hand, alkali compounds from the biomass may interact with the oxygen carrier causing problems, such as deactivation of the oxygen carrier. The most common oxygen carriers contain iron, since iron-based ores and industrial waste materials are readily available and cost-efficient. Therefore, the interaction between the iron oxygen carriers and the biomass ash-forming compounds needs to be investigated. Since Ca/Mg are abundant in biomass, it is important to clarify how their compounds interact with the oxygen carrier. In this study, the effect of Ca/Mg carbonates, chlorides, nitrates, sulfates, and phosphates along with synthetic biomass-derived ash on iron oxides was investigated. Redox reactions were investigated at 950 °C during 5 h under both oxidizing and reducing atmospheres. The results showed that the effect of Ca/Mg salts on the oxygen carrier varied depending on the anion of the salt. Generally, the nitrate- and phosphate-based salts of both Ca and Mg showed the harshest effect regarding agglomeration of the oxygen carriers. It was shown that the Ca/Mg-based compounds interacted differently with iron oxides, which was an unexpected result.
化学链燃烧（CLC）是碳捕获与封存（CCS）最具前景的方法之一。一种氧载体，即一种可被氧化和还原的矿物，在该过程中用于转化燃料。所产生的一氧化碳本质上与空气成分分离，这使得碳捕获与封存更容易实现。使用基于生物质的燃料是可取的，因为它可以实现负碳排放。另一方面，生物质中的碱化合物可能与氧载体相互作用，从而引发问题，如氧载体失活。最常见的氧载体含铁，因为铁基矿石和工业废料容易获得且成本效益高。因此，需要研究铁氧载体与生物质灰分形成化合物之间的相互作用。由于钙/镁在生物质中含量丰富，阐明它们的化合物如何与氧载体相互作用很重要。在本研究中，研究了碳酸钙/镁、氯化钙/镁、硝酸钙/镁、硫酸钙/镁和磷酸钙/镁以及合成生物质衍生灰分对铁氧化物的影响。在950℃下，在氧化和还原气氛中进行了5小时的氧化还原反应研究。结果表明，钙/镁盐对氧载体的影响因盐的阴离子而异。一般来说，钙和镁的硝酸盐和磷酸盐基盐对氧载体的团聚表现出最严重的影响。结果表明，钙/镁基化合物与铁氧化物的相互作用不同，这是一个意外的结果。
