基于颗粒粒径分布调控的新疆准东煤水煤浆成浆性研究

Study on the slurry properties of Xinjiang Zhundong coal water slurry controlled by particles size distribution

  • 摘要: 气化是煤炭清洁高效利用的关键技术之一,大型水煤浆气流床气化是目前大规模应用的先进气化技术。新疆准东地区煤炭资源储量丰富,以褐煤和长焰煤等低阶煤为主,具有高水分、高挥发分、低灰分等特点。基于传统制浆方法,准东煤的成浆浓度仅为51%,成浆性差制约了其在水煤浆气流床气化中的大规模应用。将多种技术手段结合,旨在提升准东煤的成浆浓度,从而改善准东煤气化的实用性和经济性。首先,研究了不同种类的分散剂对水煤浆表观黏度的影响,并测定了添加剂的最佳添加量,发现纯萘系干粉分散剂和准东煤具有良好的匹配性,最佳添加量为1.6%。其次,结合扫描电子显微镜、气体吸附分析仪和红外光谱仪,研究了准东煤的表面结构、比表面积大小及官能团分布,结果表明,准东煤表面结构粗糙,具有较大的比表面积,且存在一定数量的亲水性官能团,这些特性使得准东煤具有较差的成浆性。此外,结合流变性检测,发现细颗粒的添加会增加准东煤浆的黏度,同时提升其流动性,因此,选择适宜的细颗粒添加量是优化水煤浆性能的关键步骤。最后,采用三峰级配的方法筛选出合适的煤颗粒粒度和配比。当粗颗粒﹕中等颗粒﹕细颗粒的掺混比为6∶1∶3时,准东煤的成浆浓度提高到58%,流动性等级达到A且稳定性良好。

     

    Abstract: One of the most important technologies for the effective and clean use of coal is gasification. Currently, one of the most advanced gasification technologies being employed extensively is large-scale water-coal slurry entrained flow gasification. Rich coal resources may be found in Xinjiang’s Zhundong region. These resources are primarily low-rank coal, such as lignite and long flame coal, which have low ash content, high moisture content, and high volatile matter content. Based on the traditional pulping method, the slurry concentration of Zhundong coal is only 51%. Its large-scale applicability in coal water slurry fluidized bed gasification is limited by its poor slurry ability. A variety of technical means are combined to increase the slurry concentration of Zhundong coal, thereby improving the practicality and economy of Zhundong coal gasification. Initially, the study investigated the impact of various dispersant types on the apparent viscosity of water-coal slurry, and then established the optimal dosage of additives. The results indicated that pure naphthalene-based dispersants exhibited favorable compatibility with Zhundong coal, with the optimal concentration identified at 1.6%. Secondly, the surface structure, specific surface area and functional group distribution of Zhundong coal were studied by combining scanning electron microscopy, gas adsorption analyzer and infrared spectrometer. Research has indicated that Zhundong coal has a rough surface structure, a high specific surface area, and a specific quantity of hydrophilic functional groups. Because of these qualities, Zhundong coal has poor slurrying qualities. Additionally, it was discovered that adding fine particles will boost the viscosity of Zhundong coal slurry and enhance the fluidity of Zhundong coal water slurry when combined with rheological tests. Therefore, a crucial first step in maximizing the performance of water-coal slurry is determining how much tiny particles to add. Ultimately, the proper coal particle size and ratio were filtered out using the three-peak grading technique. The Zhundong coal slurry concentration climbed to 58%, the fluidity grade attained A, and the stability was good when the blending ratio of large, medium, and fine particles was 6∶1∶3.

     

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