Abstract Finding suitable low-cost materials to be used as oxygen carrier in Chemical Looping Combustion (CLC) of coal is a key issue to achieve the CO 2 capture at low economic cost. Recently, a Mn-ore from Gabon has been identified as an alternative to the state of the art of oxygen carriers based on minerals or wastes with high iron content. This Mn-ore showed a high reactivity and a long particle lifetime during batch characterization to be considered as a suitable oxygen carrier. To evaluate the potential of this material in CLC, this work analyses the behaviour of the Mn-ore during continuous combustion of a bituminous coal in a 0.5 kW th CLC unit. The CLC process was evaluated and the effect of the main operating variables - such as fluidizing medium, oxygen carrier circulation rate, temperature, and solids inventory in the fuel reactor - on the combustion efficiency and CO 2 capture was investigated. A direct relation between the char conversion rate and the CO 2 capture is given, being mainly affected by the mean residence time of solids and temperature in the fuel reactor. The use of a carbon separation system with separation efficiency above 90% would be required to achieve CO 2 capture rates higher than 95%. Total oxygen demand values as low as 4.5% were found when optimal operating conditions were selected, mainly being related to oxygen carrier to fuel ration higher than ϕ > 3. At these conditions, the Mn-ore material showed similar combustion efficiencies than other Fe-based low-cost materials previously tested, but with higher CO 2 capture rates.

中文翻译：

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以锰矿为氧载体改善煤化学循环燃烧的评价

摘要 寻找合适的低成本材料作为煤化学循环燃烧（CLC）中的氧载体是实现低成本CO 2 捕集的关键问题。最近，来自加蓬的锰矿石已被确定为现有技术的载氧体的替代品，该载氧体基于含铁量高的矿物质或废物。这种锰矿石在批次表征过程中表现出高反应性和长颗粒寿命，被认为是合适的氧载体。为了评估这种材料在 CLC 中的潜力，这项工作分析了 Mn 矿石在 0.5 kW th CLC 装置中连续燃烧烟煤期间的行为。对 CLC 工艺进行了评估，并评估了主要操作变量的影响——例如流化介质、氧载体循环速率、温度、和燃料反应器中的固体存量 - 研究了燃烧效率和 CO 2 捕获。给出了焦炭转化率和 CO 2 捕获之间的直接关系，主要受固体在燃料反应器中的平均停留时间和温度的影响。需要使用分离效率高于 90% 的碳分离系统才能实现高于 95% 的 CO 2 捕获率。Total oxygen demand values as low as 4.5% were found when optimal operating conditions were selected, mainly being related to oxygen carrier to fuel ration higher than ϕ > 3. At these conditions, the Mn-ore material showed similar combustion efficiencies than other Fe-基于先前测试过的低成本材料，但具有更高的 CO 2 捕获率。给出了焦炭转化率和 CO 2 捕获之间的直接关系，主要受固体在燃料反应器中的平均停留时间和温度的影响。需要使用分离效率高于 90% 的碳分离系统才能实现高于 95% 的 CO 2 捕获率。Total oxygen demand values as low as 4.5% were found when optimal operating conditions were selected, mainly being related to oxygen carrier to fuel ration higher than ϕ > 3. At these conditions, the Mn-ore material showed similar combustion efficiencies than other Fe-基于先前测试过的低成本材料，但具有更高的 CO 2 捕获率。给出了焦炭转化率和 CO 2 捕获之间的直接关系，主要受固体在燃料反应器中的平均停留时间和温度的影响。需要使用分离效率高于 90% 的碳分离系统才能实现高于 95% 的 CO 2 捕获率。Total oxygen demand values as low as 4.5% were found when optimal operating conditions were selected, mainly being related to oxygen carrier to fuel ration higher than ϕ > 3. At these conditions, the Mn-ore material showed similar combustion efficiencies than other Fe-基于先前测试过的低成本材料，但具有更高的 CO 2 捕获率。需要使用分离效率高于 90% 的碳分离系统才能实现高于 95% 的 CO 2 捕获率。Total oxygen demand values as low as 4.5% were found when optimal operating conditions were selected, mainly being related to oxygen carrier to fuel ration higher than ϕ > 3. At these conditions, the Mn-ore material showed similar combustion efficiencies than other Fe-基于先前测试过的低成本材料，但具有更高的 CO 2 捕获率。需要使用分离效率高于 90% 的碳分离系统才能实现高于 95% 的 CO 2 捕获率。Total oxygen demand values as low as 4.5% were found when optimal operating conditions were selected, mainly being related to oxygen carrier to fuel ration higher than ϕ > 3. At these conditions, the Mn-ore material showed similar combustion efficiencies than other Fe-基于先前测试过的低成本材料，但具有更高的 CO 2 捕获率。