Department of Environmental Engineering, Yonsei University, Wonju 26493, Republic of Korea.
Department of Environmental Engineering, Yonsei University, Wonju 26493, Republic of Korea.
J Environ Sci (China). 2019 Jun;80:58-65. doi: 10.1016/j.jes.2018.08.004. Epub 2018 Aug 31.
Elemental mercury (Hg) is predominant constituent of flue gas emitted from coal-fired power plants. Adsorption has been considered the best available technology for removal of Hg from flue gas. However, adsorbent injection increases the amount of ash generated. In the present study, powdered activated carbon (PAC) was coated on polytetrafluoroethylene/glass fiber filters to increase Hg removal while concurrently reducing the amount of ash generated. The optimal PAC coating rate was determined in laboratory experiments to ensure better Hg removal with low pressure drop. When PAC of particle size less than 45 μm was used, and the areal density was 50 g/m, the pressure drop remained under 30 Pa while the Hg removal efficiency increased to 15.8% from 4.3%. The Hg removal efficiency also increased with decrease in filtration velocity. The optimal PAC coating rate was applied on a hybrid filter (HF), which was combined with a bag filter and an electrostatic precipitator in a single chamber. Originally designed to remove fine particulates matter, it was retrofitted to the flue gas control device for simultaneous Hg removal. By employing the PAC coating, the Hg removal efficiency of the HF increased to 79.79% from 66.35%. Also, a temporary reduction in Hg removal was seen but this was resolved following a cleaning cycle in which the dust layer was removed.
元素汞（Hg）是燃煤电厂烟道气中主要的成分。吸附被认为是去除烟道气中 Hg 的最佳可行技术。然而，吸附剂的注入会增加灰分的生成量。在本研究中，将粉末状活性炭（PAC）涂覆在聚四氟乙烯/玻璃纤维滤料上，以在减少灰分生成量的同时提高 Hg 的去除率。通过实验室实验确定了最佳的 PAC 涂覆率，以确保在低压降下更好地去除 Hg。当使用粒径小于 45μm 的 PAC 且比表面积密度为 50g/m 时，压降仍保持在 30Pa 以下，而 Hg 的去除效率从 4.3%提高到 15.8%。Hg 的去除效率也随着过滤速度的降低而增加。最佳的 PAC 涂覆率应用于混合滤料（HF）上，它在一个腔室中与袋式过滤器和静电除尘器结合在一起。HF 最初的设计目的是去除细颗粒物，现在被 retrofit 到烟道气控制装置中，以同时去除 Hg。通过采用 PAC 涂覆，HF 的 Hg 去除效率从 66.35%提高到 79.79%。此外，Hg 的去除效率暂时下降，但在清除灰尘层的清洗周期后得到了恢复。
