Chemical-looping combustion (CLC) is a combustion technology in which a solid oxygen carrier is used to convert fuel. The oxygen carrier is oxidized in air and subsequently transferred to a separate reactor in which it reacts with the fuel. The produced CO₂ is inherently separated from the air components, making CLC a promising technology for carbon capture and storage (CCS). CLC of biomass combined with CCS (bioenergy CCS; BECCS) is a way to generate negative CO₂ emissions and thus interesting for climate change mitigation. Undesirable chemical reactions between ash and oxygen carriers are a challenge in BECCS because of the reactive nature of biomass ash. This article examines two low-cost steel industry byproducts that have shown desirable fuel conversion properties in CLC: iron mill scale (Glödskal B) and steel converter slag (LD-slag). Their interactions with potassium ash model compounds (KCl, K₂CO₃, K₂SO₄, and KH₂PO₄) in a reducing atmosphere have been investigated. Mixtures of oxygen carriers and potassium salt have been reduced for 6 h in CO and steam in a laboratory-scale fixed-bed reactor at 850 °C. The reduced samples have been analyzed with SEM/EDS and XRD. The reactivity of the mixtures during reduction and oxidation has also been examined by thermogravimetric analysis (TGA). K₂CO₃ increased the reaction rate for the reduction of Glödskal and inhibited the reactivity of LD-slag. KH₂PO₄ formed a K–P–Fe component with apparent low melting temperature with Glödskal, causing agglomeration, and decreased the reduction/oxidation rate in TGA. KH₂PO₄ formed a K–P–Ca component with apparent high melting temperature with LD-slag causing agglomeration but the reduction rate was not affected. The study suggests that the iron mill scale and LD-slag should not be rejected as oxygen carriers for CLC based on potassium ash interactions.

中文翻译：

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钾灰与氧气载体钢转炉炉渣和铁厂氧化皮在生物质化学循环燃烧中的相互作用-使用模型化合物进行的实验评估

化学循环燃烧（CLC）是一种燃烧技术，其中使用固体氧气载体来转化燃料。氧气载体在空气中被氧化，随后被转移到一个单独的反应器中，在其中与燃料发生反应。产生的CO ₂本质上与空气成分分离，这使CLC成为一种有前途的碳捕集与封存技术（CCS）。结合CCS（生物能源CCS； BECCS）的生物质CLC是一种产生负CO _2的方法排放，因此对于缓解气候变化很有意义。由于生物质灰分的反应性，灰分与氧气载体之间不希望的化学反应是BECCS面临的挑战。本文研究了两种低成本的钢铁行业副产品，它们在CLC中显示出理想的燃料转化性能：铁厂氧化皮（GlödskalB）和钢转炉炉渣（LD-炉渣）。它们与钾灰分模型化合物（KCl，K ₂ CO ₃，K ₂ SO ₄和KH ₂ PO _4的相互作用））在还原性气氛中已进行了研究。在实验室规模的固定床反应器中，在850°C的条件下，在一氧化碳和蒸汽中，氧载体和钾盐的混合物减少了6小时。还原后的样品已用SEM / EDS和XRD分析。还通过热重分析（TGA）检查了混合物在还原和氧化过程中的反应性。K ₂ CO ₃提高了还原Glödskal的反应速率，并抑制了LD渣的反应性。KH ₂ PO ₄与Glödskal形成的K-P-Fe组分具有明显较低的熔融温度，引起团聚，并降低了TGA中的还原/氧化速率。KH ₂ PO ₄形成了明显具有较高熔化温度的K–P–Ca成分，并带有LD炉渣，导致团聚，但还原率不受影响。研究表明，基于钾灰分相互作用，不应拒绝铁厂氧化皮和LD渣作为CLC的氧气载体。