Biomass Conversion and Biorefinery ( IF 3.5 ) Pub Date : 2022-01-13 , DOI: 10.1007/s13399-021-02184-4 Yuefeng Wang 1 , Fang Cao 1 , Chong He 1 , Yuexing Wei 1 , Yuhong Qin 1 , Yanyun He 1 , Shugang Guo 2 , Xing Du 2 , Stanislav V. Vassilev 3 , Christina G. Vassileva 3
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One of the challenges for large-scale biomass gasification is inevitable ash-related problems such as ash deposition, corrosion, fouling, acid gas emission, and others, mainly caused by the volatile ash-forming elements in biomass. Water washing is an efficient, low-cost, and manageable way to alleviate these ash-related problems by reducing the concentrations of ash-forming elements in biomass. The leaching characteristics of ash-forming elements such as K, Na, Ca, Mg, Al, Fe, S, Cl, and P of corn straw (CS) were studied by inductively coupled plasma mass spectrometry (ICP-MS), ion chromatography (IC), and ultraviolet–visible spectroscopy (UV–Vis) during water washing at different time and temperatures. It was found that the water washing process removes almost all of K, Cl, and P with a removal efficiency higher than 90% within the first 10 min; large proportions of S, Na, and Mg with a removal efficiency of more than 70% within 120 min; and small amounts of Ca, Al, and Fe with a removal efficiency less than 63% within 120 min even at 50 ºC. The kinetic analysis indicated that the leaching of ash-forming elements was a two-step process consisting of an initial fast step and a second slow step. The leaching of ash-forming elements might be controlled by the first-order kinetic model, namely, homogeneous model and shrinking core model. Still, the second-order reaction model presents high regression coefficients, which is better suitable to fit the leaching kinetics of ash-forming elements from CS than the first-order kinetic leaching model. The reaction rate for the second-order reaction is faster than the first-order reaction during the water leaching of CS. The water washing could reduce the slagging tendency in the gasifier and diminish the emission of acid gases during corn straw gasification.
Graphical abstract
中文翻译：
玉米秸秆水洗过程中成灰元素的浸出机理
大规模生物质气化的挑战之一是不可避免的与灰相关的问题，如灰沉积、腐蚀、结垢、酸性气体排放等，主要由生物质中的挥发性成灰元素引起。水洗是一种有效、低成本且易于管理的方法，可通过降低生物质中形成灰分的元素的浓度来缓解这些与灰分相关的问题。采用电感耦合等离子体质谱法(ICP-MS)、离子色谱法研究了玉米秸秆(CS)中成灰元素K、Na、Ca、Mg、Al、Fe、S、Cl、P的浸出特性(IC) 和紫外-可见光谱 (UV-Vis) 在不同时间和温度的水洗过程中。结果表明，水洗过程在前 10 分钟内去除了几乎所有的 K、Cl 和 P，去除效率高于 90%；大比例的S、Na、Mg，120分钟内去除率达70%以上；少量的 Ca、Al 和 Fe，即使在 50 ºC 下也能在 120 分钟内去除效率低于 63%。动力学分析表明，成灰元素的浸出是一个两步过程，包括一个初始快速步骤和第二个慢速步骤。成灰元素的浸出可能受一级动力学模型控制，即均质模型和收缩芯模型。尽管如此，二级反应模型呈现出较高的回归系数，这比一级动力学浸出模型更适合拟合成灰元素从 CS 中的浸出动力学。在 CS 的水浸过程中，二级反应的反应速率比一级反应快。
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