Chen Zhichao, Tian Xiaodong, Hou Jian, Li Zhengqi, Xu Yongwei, Feng Yuanyuan
School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin, 150001, PR China.
Western Mining Group Technology Development Co., Ltd., Xining, 810000, PR China; State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu, 730000, PR China.
Environ Res. 2023 Nov 1;236(Pt 2):116802. doi: 10.1016/j.envres.2023.116802. Epub 2023 Aug 3.
Coal gasification fine ash (CGFA) is characterized by high yield, high carbon content, and difficult recovery. This results in waste of coal resources and serious environmental pollution. To address this issue, a novel green deashing process is proposed in this study to modify CGFA into deashed carbon (DAC) with a high calorific value and an ash content of less than 5% through a low-temperature alkaline fusion process. Compared with traditional alkaline fusion (which is carried out at 600-1000 °C), low-temperature alkaline fusion treatment can efficiently remove ash minerals in the temperature range of 300-450 °C, which is beneficial to the efficient recovery of residual carbon in DA, while simultaneously improving the physicochemical properties and energy characteristics of DAC, thereby improving its combustion performance. At an alkali fusion temperature of 350 °C, a NaOH:DA ratio of 4.5:1, and a reaction time of 40 min, the resulting DAC product had ash content of 2.28%, combustible material recovery (CMR) of 82.03%, higher heating value (HHV) of 31.07 MJ kg, and S of 445.43 m g. In comparison, it was found that low-temperature alkali fusion significantly improved the deashing of CGFA when compared to existing deashing technologies. These results strongly suggest that this innovative deashing method can modify CGFA into a high-calorific value and low-N and S fuel, thereby providing a cost-effective and sustainable utilization method for CGFA.
煤气化细灰（CGFA）具有产量高、碳含量高和回收困难的特点。这导致煤炭资源浪费和严重的环境污染。为了解决这个问题，本研究提出了一种新型绿色脱灰工艺，通过低温碱熔工艺将CGFA转化为热值高、灰分含量低于5%的脱灰碳（DAC）。与传统碱熔（在600-1000℃下进行）相比，低温碱熔处理能在300-450℃的温度范围内有效去除灰分矿物质，这有利于DA中残余碳的高效回收，同时改善DAC的物理化学性质和能量特性，从而提高其燃烧性能。在碱熔温度为350℃、NaOH:DA比例为4.5:1、反应时间为40分钟时，所得DAC产品的灰分含量为2.28%，可燃物回收率（CMR）为82.03%，高热值（HHV）为31.07 MJ/kg，硫含量为445.43 mg/kg。相比之下，发现与现有脱灰技术相比，低温碱熔显著提高了CGFA的脱灰效果。这些结果有力地表明，这种创新的脱灰方法可以将CGFA转化为高热值、低氮和低硫燃料，从而为CGFA提供一种经济高效且可持续的利用方法。
