Abstract

Developing an effective cleaner process technology for maize-cob biomass wastes is of utmost importance. This work involved the comparison of products yield (bio-oil, biogas, and biochar) from the fast, slow, and flash pyrolysis of maize-cob biomass wastes using a fixed-bed reactor; evaluation of the individual and combined influences of pyrolysis temperature, biomass particle size, and residence time on the yield of product, and the determination of the optimum pyrolysis conditions/products yield of fast pyrolyzed maize-cob. The fast pyrolysis was performed according to the Box-Behnken Design of Experiment with three variables and three levels of the response surface methodology. The bio-oil fuel properties were determined utilizing ASTM methods and chemically characterized using CHNS elemental analyzer, GC/MS, and FTIR. The performance of the three pyrolysis techniques in terms of their product yield is in the following order: Flash pyrolysis > Fast pyrolysis > Slow pyrolysis (for bio-oil); Slow pyrolysis > Fast pyrolysis > Flash pyrolysis (for biochar and biogas). An optimum bio-oil yield of 43.13% with a high heating value (HHV) of 30.59 MJ/kg, biochar yield of 37.18% with HHV of 20.41 MJ/kg, and biogas yield of 26.05% (HHV = 13.19 MJ/kg) was respectively obtained at an optimum temperature of 567.72, 463.71, and 593.17 °C; biomass particle size of 0.51, 3.83, and 2.58 mm; and residence time of 10.01, 15.28, and 18.92 min. The determined physicochemical characterized properties of the maize-cob-derived-bio-oil revealed that the bio-oil can potentially be valued as a biofuel and as a more promising feedstock for value-added chemical production.

摘要

为玉米芯生物质废物开发一种有效的清洁工艺技术至关重要。这项工作涉及比较使用固定床反应器对玉米芯生物质废物进行快速、慢速和闪速热解的产品产量（生物油、沼气和生物炭）；评估热解温度、生物质粒度和停留时间对产品收率的单独和综合影响，确定快速热解玉米芯的最佳热解条件/产品收率。快速热解是根据 Box-Behnken 实验设计进行的，具有三个变量和三个水平的响应面方法。使用 ASTM 方法测定生物油燃料特性，并使用 CHNS 元素分析仪、GC/MS 和 FTIR 进行化学表征。三种热解技术在产品收率方面的表现按以下顺序排列：快速热解 > 快速热解 > 慢速热解（用于生物油）；慢速热解 > 快速热解 > 快速热解（用于生物炭和沼气）。最佳生物油产率为 43.13%，高热值（HHV）为 30.59 MJ/kg，生物炭产率为 37.18%，HHV 为 20.41 MJ/kg，沼气产率为 26.05%（HHV = 13.19 MJ/kg）分别在最佳温度567.72、463.71和593.17 ℃下得到；生物质颗粒大小为 0.51、3.83 和 2.58 毫米；和 10.01、15.28 和 18.92 分钟的停留时间。确定的玉米芯衍生生物油的物理化学特性表明，该生物油可以潜在地被视为一种生物燃料，并作为一种更有希望的用于增值化学品生产的原料。