Empirical Models with Constant and Variable Activation Energy for Biomass Pyrolysis

Kinetic models for biomass pyrolysis

Biomass is a versatile material. It can be directly combusted to produce heat; however, by first subjecting it to a thermal or biological degradation, it can also be converted to products with a higher heating value or to materials with properties superior to those of the raw material [1]. When heated in the absence of oxygen, biomass decomposes into a range of products; including char (solid),...

Double Distribution Activation Energy Model as Suitable Tool in Explaining Biomass and Coal Pyrolysis Behavior

Understanding and modeling of coal and biomass pyrolysis assume particular importance being the first step occurring in both gasification and combustion processes. The complex chemical reaction network occurring in this step leads to a necessary effort in developing a suitable model framework capable of grasping the physics of the phenomenon and allowing a deeper comprehension of the sequence o...

Biomass Pyrolysis for Hybrid Biorefineries

Field theory models for variable cosmological constant

Anthropic solutions to the cosmological constant problem require seemingly unnatural scalar field potentials with a very small slope or domain walls (branes) with a very small coupling to a four-form field. Here we introduce a class of models in which the smallness of the corresponding parameters can be attributed to a spontaneously broken discrete symmetry. We also demonstrate the equivalence ...

Approximations to the Distributed Activation Energy Model for Pyrolysis

The Distributed Activation Energy Model (DAEM), used for the pyrolysis of a range of materials (including coal, biomass, residual oils and kerogen), assumes that the thermal decomposition of numerous components is described by a distribution of activation energies. Existing theories are reviewed with particular focus on methods used to evaluate solutions quickly and efficiently. This paper demo...