Abstract Chemical looping combustion (CLC) processes combined with CO 2 sequestration and sustainable management of biomass represent a promising BioEnergy with Carbon Capture and Storage (BECCS) technology. One of the aspects to be considered in the combustion of biomass is the formation of NO x and the possible existence of tar in the gaseous product stream. The advantage of the CLC technology compared to other CO 2 capture technologies is that only fuel-N contributes to nitrogen oxides formation. Moreover, scarce information is available about tar formation in CLC. Thus, this work focuses on these two aspects and compares the results obtained when two different chemical looping combustion modes are used, namely In Situ Gasification Chemical Looping Combustion ( i G-CLC) and Chemical Looping with Oxygen Uncoupling (CLOU). Important differences were observed depending on the combustion mode. In both cases most of the fuel-N appeared as N 2 in the fuel reactor. However, in i G-CLC more than 94% of the nitrogen measured in the fuel reactor was N 2 independently of the biomass used. These percentages under the CLOU mode were lower. In this case, low amounts of N 2 O were also detected, although it decreased to almost zero at 850 °C. In the air reactor, NO was found and its concentration remained below the legal limit for NO x emissions in power installations with all the types of biomass tested and operating modes. Tar species and concentrations found at the fuel reactor outlet stream were different under the two combustion modes. About 2.5–3.7 g/Nm 3 total tar could be found at 980 °C burning under i G-CLC mode, mostly naphthalene. On the contrary, insignificant tar amounts were found in CLOU.

中文翻译：

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iG-CLC和CLOU模式下生物质化学循环燃烧中燃料-N和焦油演化的对比研究

摘要 化学循环燃烧 (CLC) 过程与 CO 2 封存和生物质可持续管理相结合，代表了具有碳捕获和储存 (BECCS) 技术的有前途的生物能源。在生物质燃烧中要考虑的方面之一是 NO x 的形成和气态产物流中可能存在的焦油。与其他 CO 2 捕获技术相比，CLC 技术的优势在于只有燃料氮有助于氮氧化物的形成。此外，关于 CLC 中焦油形成的信息很少。因此，这项工作侧重于这两个方面，并比较了使用两种不同的化学循环燃烧模式时获得的结果，即原位气化化学循环燃烧 (i G-CLC) 和带氧解偶联的化学循环 (CLOU)。根据燃烧模式观察到重要差异。在这两种情况下，大部分燃料-N 在燃料反应堆中都以 N 2 的形式出现。然而，在 i G-CLC 中，在燃料反应器中测量的超过 94% 的氮是 N 2 ，而与所使用的生物质无关。CLOU 模式下的这些百分比较低。在这种情况下，也检测到少量的 N 2 O，尽管它在 850 °C 时减少到几乎为零。在空气反应器中，在所有类型的生物质测试和运行模式下，都发现了 NOx，其浓度仍低于电力装置中 NOx 排放的法定限值。在两种燃烧模式下，在燃料反应器出口物流中发现的焦油种类和浓度不同。在 i G-CLC 模式下，在 980 °C 燃烧时可以发现大约 2.5-3.7 g/Nm 3 的总焦油，主要是萘。相反，