A Study into the Influence of Different Factors on the Behavior of Alkaline Element Concentrations that Cause Bed Agglomeration

G. A. Ryabov; O. M. Folomeev; O. A. Smirnova; D. S. Litun

摘要

In recent years, studies into the processes of bed agglomeration during the combustion of biomass have become increasingly relevant. The agglomeration processes are most largely influenced by the alkaline components of ash, which form low-melting eutectics by reacting with silicates. Therefore, it is very important to determine the critical concentration, primarily, of potassium that forms the most low-melting eutectics in the bed, at which the particles begin to sinter. The experimental studies are aimed at to investigate the effect of the temperature and the concentrations of alkaline elements on the process of particle agglomeration during the combustion of various types of biomass as well as biomass and coal, studying the presence of bed drain, determining the critical concentration of potassium in the bed, and calculating the estimated time before the start of sintering under conditions of an increase of potassium concentration in the bed. The experimental techniques and characteristics of the four studied types of biomass are described. Data on the fraction of agglomerated particles in the bed at different temperatures and concentrations of alkaline elements are given. Upon replacing a part of the sand by iron oxides, agglomeration is observed only at high temperatures (850°C and more). The obtained data are compared with the results of similar experiments carried out under conditions of the fluidized bed; in these experiments, the effects of the fluidization rate, particle size, and excess air on the agglomeration processes are considered. It is noted that the limiting potassium concentration is lowest in the case of a fixed bed. It is shown that real objects should be used when studying the dependence of the behavior of the potassium concentration in the bed on the operation time. The choice of the fraction of bed drain with the addition of a screened material or fresh sand is of practical interest. The calculation techniques and calculated data obtained with use of them on the behavior of the potassium concentration in the bed under various conditions are presented. The fractions of bed drain during combustion of sunflower husks and bark and wood waste are determined. In addition, it is shown that the joint combustion of husks and coal sharply reduces the probability of bed agglomeration.

机译：近年来，研究生物质燃烧过程中床块过程的研究变得越来越相关。聚集过程最大限度地受灰分的碱性成分影响，其通过与硅酸盐反应形成低熔点的共肠。因此，确定临界浓度，主要是在床中形成最低熔点的钾的钾，在该颗粒开始烧结时是非常重要的。实验研究旨在探讨温度和碱性元素浓度对各种类型生物质和生物质和煤的颗粒附聚过程的影响，研究床排水管的存在，确定临界在床上浓度浓度，并在床上钾浓度增加的条件下计算烧结开始前的估计时间。描述了四种研究的生物质类型的实验技术和特征。给出了不同温度下床中凝聚颗粒的级分的数据和碱性元素浓度的数据。通过氧化铁代替砂的一部分时，仅在高温（850℃和更多）处观察到附聚。将获得的数据与在流化床条件下进行的类似实验的结果进行比较;在这些实验中，考虑了流化速率，粒度和过量空气对聚集过程的影响。应注意，在固定床的情况下，限制钾浓度最低。结果表明，在研究床上的操作时间时应在研究钾浓度的行为的依赖性时使用真实物体。添加筛分材料或新鲜沙子的床流量分数是实际兴趣的。通过使用它们在各种条件下使用它们在床中钾浓度的行为获得的计算技术和计算的数据。确定了向日葵壳和树皮和木材废料期间床排水的级分。此外，表明壳体和煤的联合燃烧急剧降低了床附聚的概率。

A Study into the Influence of Different Factors on the Behavior of Alkaline Element Concentrations that Cause Bed Agglomeration

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