Stochastic reactor modeling of biomass pyrolysis and gasification

Abstract

In this paper, a partially stirred stochastic reactor model is presented as an alternative for the modeling of 17 biomass pyrolysis and gasification. Instead of solving transport equations in all spatial dimensions as in CFD 18 simulations, the description of state variables and mixing processes is based on a probability density function, making 19 this approach computationally efficient. The virtual stochastic particles, an ensemble of flow elements consisting of 20 porous solid biomass particles and surrounding gas, mimic the turbulent exchange of heat and mass in practical 21 systems without the computationally expensive resolution of spatial dimensions. Each stochastic particle includes 22 solid phase, pore gas and bulk gas interaction. The reactor model is coupled with a chemical mechanism for both 23 surface and gas phase reactions. A Monte Carlo algorithm with operator splitting is employed to obtain the numerical 24 solution. Modeling an entrained flow gasification reactor demonstrates the applicability of the model for biomass 25 fast pyrolysis and gasification. The results are compared with published experiments and detailed CFD simulations. 26 The stochastic reactor model is able to predict all major species in the product gas composition very well for only a 27 fraction of the computational time as needed for comprehensive CFD. 28 29

The multi-scale challenges of biomass fast pyrolysis and bio-oil upgrading: Review of the state of art and future research directions

“…Weber et al [637], using a probability density function to describe state variables and mixing processes, and a Monte Carlo algorithm with operator splitting to solve the problem.…”

Chemical Model for Thermal Treatment of Sewage Sludge

“…It is selected since it is targeted to solve large detailed chemistry schemes and to resolve the devolatilization, heterogeneous reactions of solid and gas phase, and reactions in the gas phase. Depending on the provided chemistry and operating conditions, it allows us to model pyrolysis, gasification, and combustion applications [31,41,42].…”

“…The mass source term from solid to gas phase is used to update the representative diameters of the solid particles. A more detailed description of the model is provided elsewhere [40][41][42].…”

“…The reactor can be run as a single or series of partially stirred reactors [40,41], partially stirred plug flow reactors [40,41], or connected to a reactor network model for grate-fired applications [31,42].…”

Biomass Hydrothermal Carbonization: Markov-Chain Monte Carlo Data Analysis and Modeling

“…Clear examples of this course are prediction techniques such as non-linear random forest models (Li et al, 2020), the design of experiments using surface response techniques (Román et al, 2020), and the assessment of models using high-pressure differential scanning calorimetry (Pecchi et al, 2020). The studies are expanding, aiming to bring the HTC modeling to maturity, as occurs for other biomass thermochemical conversions, such as pyrolysis and gasification (Weber et al, 2017;Safarian et al, 2019). In the authors' opinion, stochastic techniques could contribute effectively to perfect kinetic models and analyze experimental data.…”