Multiscale modeling of biomass pretreatment for optimization of steam explosion conditions

Steam explosion is the most cost-effective and widely used method for pretreating lignocellulosic materials. Unlike other hydrothermal pretreatment technologies, it is characterized by physical tearing effects. The severity factor cannot represent the effects of instantaneous decompression but it can depict the effects of high-temperature cooking. Using the theories of heat transfer, momentum transfer, and brittle fracture mechanics as bases, we analyze physical tearing in instantaneous decompression. Moisture content of materials wopt is optimized by maintaining temperature T (T↔wopt), and chip size d is optimized with discharge port area A (A∝d2). The chip size, moisture content of materials, and discharge port area are then incorporated into the severity factor. The enriched severity factor and the relationship among operation parameters, material property parameters, and equipment parameters serve as engineering references in designing the equipment and selecting the conditions for steam explosion technology. Such equipment and conditions are suitable for use under any given set of materials, products, and treatment targets.

► Multiscale models are established for steam explosion condition optimization. ► Relationship of biomass moisture content and holding temperature is established. ► Relationship of biomass chip size and discharge port area is established. ► Severity factor enriched with chip size, moisture content and discharge port area.