A novel gas removal method for the removal of C2H2 in calcium carbide slag slurry by fine bubbles combined with air purging: performance, mechanism, and in situ bubble imaging analysis
A novel gas removal method for the removal of C2H2 in calcium carbide slag slurry by fine bubbles combined with air purging: performance, mechanism, and in situ bubble imaging analysis
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DOI：
10.1016/j.seppur.2022.122987
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发表时间：
2022-12
影响因子：
8.6
通讯作者：
Zi-He Meng;Ganyu Zhu;Huiquan Li;Shaopeng Li;Kun-Hong Yan;Yue-Ting Yang
中科院分区：
文献类型：
--
作者：
Zi-He Meng;Ganyu Zhu;Huiquan Li;Shaopeng Li;Kun-Hong Yan;Yue-Ting Yang
水泥行业约60%的碳排放来自石灰石的分解。电石渣（CCS，低碳钙质材料）作为原料替代的关键低碳技术，可以替代石灰石生产水泥、脱硫剂等产品，实现碳减排和CCS的升级循环。然而，CCS中残留C2 H2的释放带来了安全和环境风险，严重制约了CCS的升级循环。本文提出了一种新的脱除固体CCS颗粒中C2 H2气体的方法--细气泡（FB s）脱气法，并利用先进的原位气泡成像技术研究了CCS颗粒中C2 H2的脱除性能和机理。结果表明，CCS中约70%的C2 H2（包封的C2 H2）难以通过干燥或浆化除去。在最佳工艺条件下，C2 H2脱除率为61.0%，C2 H2释放量降低了92.9%。在流化床脱气过程中，CCS浆料中的大颗粒CCS通过侵蚀机制破碎成细颗粒，从而促进包覆的电石与水反应生成C2 H2。生成的C2 H2溶解在浆液中，在微负压下，可被直径小于500 μm的流化床以较快的传质速率快速去除。本工作为有效脱除CCS中C2 H2并避免安全和环境风险提供了一种新颖的气体脱除方法，为CCS的升级循环提供了技术支持，并为其他类似多相体系（如，气-液/气-液-固、油-液/油-液-固）。
About 60% of carbon emissions in the cement industry come from the decomposition of limestone. As a key low-carbon technology of raw material substitution, calcium carbide slag (CCS, low-carbon calcareous material) can replace limestone to produce cement, desulfurizer, and other products, which can achieve carbon emission reduction and the upcycling of CCS. However, the release of residual C2H2in CCS brings safety and environmental risks, which seriously restricts the upcycling of CCS. In this study, a novel gas removal method of fine bubbles (FBs) degassing was proposed for the removal of C2H2in solid CCS particles, and an advanced in situ bubble imaging technology was used to investigate the performance and mechanism of C2H2removal. The results indicated that approximately 70% of C2H2(encapsulated C2H2) in CCS was difficult to remove by drying or slurrying. Under the optimal condition, the C2H2removal efficiency was approximately 61.0%, and the amount of C2H2released from the CCS slurry decreased by 92.9%. In the process of FBs degassing, large CCS particles in the CCS slurry were broken up into fine particles via the erosion mechanism, thus promoting the reaction of the encapsulated calcium carbide with water to produce C2H2. The generated C2H2was dissolved in the slurry and could be quickly removed by FBs (<500 μm) with a fast mass transfer rate under the slight negative pressure. This work provides a novel gas removal method for effectively removing C2H2in CCS and avoiding security and environmental risks, provides technical support for the upcycling of CCS, and provides a reference for the separation of other similar multiphase systems (e.g., gas–liquid/gas–liquid–solid, oil-liquid/oil-liquid–solid).