Biomass pelletization technology overcame the poor utilization and handling properties of loose materials. The quality of pellets is sensitive to the pelletization conditions. In this work the impact of the operating parameters as pressure, temperature, and moisture content on the mechanical characteristics as the compression strength (\({\sigma }_{max}\)) and durability (\(Du\)) and energy consumption for both production (\({E}_{c,p}\)) and ejection (\({E}_{c,ej}\)) of rice straw (RS) pellets was studied. Furthermore, the synergic effect of these parameters on the pellet characteristics was evaluated at the optimum conditions. The operating parameters were optimized using a multi-objective optimization approach of Response Surface Method (RSM) based on the predicted significant models that describe the physical characteristics of the pellets. The optimization results showed that high quality pellets could be produced at a pressure of 68.4 MPa, temperature of 110.0 °C, and moisture of 8.2% for solid pellets and 63.6 MPa, 110.0 °C, and 8.7% for hollow pellets. Significant individual and interaction effects of all independent parameters on the pellets characteristics were investigated using statistical analysis results, main plot curves and 2D interaction contour plots. New significant empirical dimensionless relationships that correlate the characteristics of pellets were proposed. These relationships can be generalized for any type of pellets that produced under various operating conditions. Hollow pellets are recommended to be used in the industrial sector due to their enhanced heat transfer which resulted from the high surface to volume ratio besides their ease production at normal operating condition similar to that required for solid pellets.

Graphic Abstract

中文翻译：

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使用操作参数的统计分析，固体和空心生物质颗粒生产的机械特性和能耗

生物质制粒技术克服了松散材料的不良利用和处理特性。粒料的质量对粒化条件敏感。在这项工作中，压力，温度和水分含量等操作参数对机械特性的影响包括抗压强度（\（{\ sigma __ {max} \））和耐久性（\（Du \））和能量生产（\（{E} _ {c，p} \））和喷射（\（{E} _ {c，ej} \）的消耗）研究了稻草（RS）颗粒。此外，在最佳条件下评估了这些参数对颗粒特性的协同作用。使用响应面法（RSM）的多目标优化方法，基于描述颗粒物理特性的预测显着模型，对操作参数进行了优化。优化结果表明，对于固体颗粒，可以在68.4 MPa的压力，110.0°C的温度和8.2％的湿度下生产高质量的颗粒，对于空心颗粒，可以在63.6 MPa，110.0°C和8.7％的条件下生产高质量的颗粒。使用统计分析结果，主图曲线和2D交互作用等高线图，研究了所有独立参数对颗粒特性的重大个体和相互作用影响。提出了与颗粒特性相关的新的重要的经验无因次关系。这些关系可以概括为在各种操作条件下生产的任何类型的颗粒。由于中空颗粒的传热增强（高表面积体积比引起），并且在正常操作条件下易于生产（类似于固体颗粒所需的条件），因此建议在工业领域中使用。

图形摘要