文献类型：期刊文献

英文题名：The key for sodium-rich coal utilization in entrained flow gasifier: The role of sodium on slag viscosity-temperature behavior at high temperatures

作者：Chen, Xiaodong[1,2];Kong, Lingxue[1,3];Bai, Jin[1];Dai, Xin[1,2];Li, Huaizhu[1];Bai, Zongqing[1];Li, Wen[1]

机构：[1]Chinese Acad Sci, Inst Coal Chem, State Key Lab Coal Convers, Taiyuan 030001, Shanxi, Peoples R China;[2]Univ Chinese Acad Sci, Beijing 100049, Peoples R China;[3]East China Univ Sci & Technol, Key Lab Coal Gasificat & Energy Chem, Minist Educ, POB 272, Shanghai 200237, Peoples R China

年份：2017

卷号：206

起止页码：1241

外文期刊名：APPLIED ENERGY

收录：;EI(收录号：20174204278044);WOS:【SCI-EXPANDED(收录号:WOS:000415768400102)】；

基金：This work was supported by the National Natural Science Foundation of China (grant numbers 21406254 and 21476247), Joint Foundation of Natural Science Foundation of China and Shanxi Province (grant number U1510201), Shanxi Province Science Foundation for Youths (grant number 2015021055), the Fundamental Research Funds for the Central Universities (grant number 222201717004), Youth Innovation Promotion Association, CAS, the CAS/SAFEA International Partnership Program for Creative Research Teams, and the Foundation of State Key Laboratory of Coal Conversion (grant number J13-14-301).

语种：英文

外文关键词：Entrained flow gasification; Sodium-rich coal; Viscosity-temperature behavior; Network structure; Crystallization tendency

摘要：Tremendous sodium-rich coal in China has unique ash compositions, and the entrained flow gasification is one of the best choices to use sodium-rich coal for coal chemical industry. The entrained flow gasifiers require smooth slag tapping for long term and safe running, but the viscosity-temperature behavior of high-sodium slags is unknown, which limits the utilization of sodium-rich coal. In this study, viscosity-temperature behavior of high sodium coal ash slags was revealed for the first time, and the parameter of slag network structure and index of slag crystallization tendency is raised for slag viscosity evaluation. The results show that Na2O provides O2- ions which break Si-O-Si bonds and slag network structure. However, Al3+ ions are absorbed into silicate network, acting as a network former with the ionic charge-compensation effect of Na+. The classic structural parameter (fraction of non-bridging oxygen, NBO) is modified to evaluate the high-sodium slag viscosity accurately by taking Al3+ into account. NBO fraction decreases as Na2O content increases, leading to the decrease of slag viscosity. Below T-liq, slags are prone to be crystalline slag with increasing Na2O content or glassy slag with increase in SiO2/Al2O3 ratio (S/A). A novel index, namely glassy slag formation ability (G), is established to quantitatively evaluate the crystallization tendency of coal ash slags. G is the ratio of activation energy for viscous flow (E-eta) to T-liq. The slag will exhibit the glassy behavior when G is higher than 0.16 kJ/(mol.K). The results enhance the knowledge of viscosity-temperature behavior of high-sodium coal ash slags and will be helpful for coal selection and blending to avoid slag blockage in entrained flow gasification.