煤炭是我国主要能源资源,而准东煤田作为我国最大的整装煤田,具有非常高的开发利用 价值。 但准东煤中 Na、Ca 等碱金属和碱土金属(AAEMs)含量较高,导致在工业生产中结渣沾污问 题严重。 为探究 CO2 -水洗处理对准东高碱煤的脱碱效果及水洗过程溶液中 Cl- / NO-3 等阴离子的 分布特性,进行水洗 / CO2 -水洗准东煤脱碱实验。 在水洗温度为 20、40、60 °C ,水洗时间为 2、5、8 h 等不同水洗条件下,对水洗/CO2-水洗准东煤Na/Ca和Cl-/NO-3 的脱除性能进行对比分析,并对其 他气体氛围下水洗准东煤脱除Na/Ca的可行性进行探讨。 实验结果表明:随着水洗时间、温度及 水煤液固质量比的增加,Na/Ca的脱除效率增加且增幅较大,滤液中Cl-/NO-3 等阴离子浓度也有所 增大。 当水洗时间为 5 h、水洗温度为 60 °C、液固比为 50 ∶ 1、CO2 通入流量为 100 mL/ min 时, Na/Ca的脱除效果达到较高水平,脱除效率分别可达73.8%和15.0%。 Na/Ca的脱除效率与CO2流 量和CO2/O2混合气体中CO2体积分数基本呈正相关,而CO2流量对Cl-/NO-3 的浸出也具有一定的 抑制和促进作用,其中滤液中 Cl- / NO-3 质量浓度随 CO2 流量变化有所波动,除物理上的鼓泡作用 外,可能存在其他化学反应机理。 在其他气体氛围(如N2氛围)下水洗准东煤,Na/Ca的脱除效果 也有一定改善,但没有 CO2 参与水洗的脱碱效果好。 因此,将 CO2 应用于水洗准东煤脱碱切实可 行,并具有良好的应用前景,通过合理的工业流程改造,有望实现一定规模的工业化应用。

In China,coal is still a dominant energy resource,and the Zhundong coalfield,as the largest coalfield,is of great potential for exploitation. However,the high content of alkali and alkaline earth metals (AAEMs) such as Na and Ca in the Zhundong coal has led to some serious slag staining problems in industrial production. Therefore,to in- vestigate the specific effect of CO2 -water washing treatment on the dealkalization of the Zhundong high-alkali coal and the distribution characteristics of anions such as Cl- / NO-3 in the solution during the washing process,the water washing / CO2 -water washing experiments of the Zhundong coal were carried out. By varying different washing conditions such as washing temperature of 20,40,60 °C and washing time of 2,5,8 h,a comparative analysis of the effect of Na / Ca and Cl- / NO-3 ions removal from the Zhundong coal by water washing / CO2 - water washing was carried out. And the feasibility of Na / Ca removal from water washing under other gas atmospheres was also explored. The experi- mental results showed that with the increase of washing time,washing temperature and liquid-solid ratio,the removal efficiencies of Na and Ca increased,while the concentrations of Cl- and NO-3 ions in the washing filtrate also increased. The Na and Ca removal efficiencies could reach a high level when the washing time was 5 h,the washing temperature was at 60 °C ,the liquid-solid ratio was 50 ∶ 1,and the CO2 flow rate was 100 mL / min,with a removal efficiency of 73.8% for Na and 15.0% for Ca. The removal efficiencies of Na / Ca are basically positively correlated with the CO2 flow rate and the volume ratio of CO2 in the CO2 / O2 mixture. The flow rate of CO2 also had a certain inhibitory and promotional effect on the leaching of Cl- / NO-3 ions,where the concentrations of Cl- / NO-3 ions fluctuated with the CO2 flow rate. Apart from the physical bubbling effect,there might be other chemical reaction mechanisms. Water washing on the Zhundong coal under other gas atmospheres,such as N2 ,also resulted in some enhancement of the Na / Ca re- moval. However,the dealkalization effect of the Zhundong coal by N2 -water washing is worse than that obtained by CO2 -water washing. Therefore,the application of CO2 to water washing the Zhundong coal for dealkalization is feasible and promising for development and application,which is expected to be promoted on a certain scale in industry through some reasonable modifications of industrial processes.