ABSTRACT

Semi-coke briquette used in stoves could reduce the primary PM_2.5 emission and lower the material cost advantages. While the manufacturing cost of semi-coke briquette is relatively high due to the weak cohesiveness of semi-coke. The cost-effective and environment-friendly briquetting technology still needs to be developed for clean utilization of fine semi-coke. A novel preparation method of semi-coke briquette with alkali-heat-treated wheat straw (AH-WS) binder was put forward in this study. The physical characteristics of the semi-coke briquette were analyzed experimentally. Infrared spectroscopies indicated that AH-WS obtained in the mixed lye comprised 4% Ca(OH)₂ and 0.04% NaOH featured higher cellulose and O-H group concentrations than those in 4% Ca(OH)₂. Therefore, the mixed lye could play a better role in briquette binding. Scanning electron microscope images revealed that higher AH-WS ratio enlarged the area of solid bridges during densification and improved the strength and density of briquette. The orthogonal analysis determined the optimum briquetting parameters were 8% moisture, 25% AH-WS, 5% clay and as low as 15 MPa forming pressure, which could obtain the semi-coke briquette with compressive strength above 20 MPa and bomb calorific value beyond 19 MJ/kg. Present work could promote the application of semi-coke briquette for household.

摘要

用于炉灶的半焦型煤可以减少初级PM _2.5排放并降低材料成本优势。而半焦型煤的制造成本相对较高，因为半焦的内聚力较弱。精细半焦的清洁利用仍需开发经济高效、环保的压块技术。本研究提出了一种以碱热处理麦秸(AH-WS)为粘合剂制备半焦型煤的新方法。对半焦型煤的物理特性进行了实验分析。红外光谱表明，在混合碱液中获得的AH-WS由4% Ca(OH) ₂和0.04% NaOH组成，其纤维素和OH基浓度高于4% Ca(OH) ₂. 因此，混合碱液在型煤粘合中可以发挥更好的作用。扫描电镜图像显示，较高的 AH-WS 比增大了致密化过程中的固体桥面积，并提高了型煤的强度和密度。正交分析确定最佳成型参数为水分8%、AH-WS25%、粘土5%，成型压力低至15 MPa，可获得抗压强度20 MPa以上、弹热值超过19 兆焦耳/公斤。目前的工作可以促进半焦型煤在家庭中的应用。