Biomass pyrolysis modeling of systems at laboratory scale with experimental validation

Abstract

Purpose Thermochemical conversion processes are one of the possible solutions for the flexible production of electric and thermal power from biomass. The pyrolysis degradation process presents, among the others, the interesting features of biofuels and high energy density bio-oil production potential high conversion rate. In this paper, numerical results of a slow batch and continuous fast pyrolyzers, are presented, aiming at validating both a tridimensional computational fluid dynamics-discrete element method (CFD–DEM) and a monodimensional distributed activation energy model (DAEM) represents with data collected in dedicated experiments. The purpose of this paper is then to provide reliable models for industrial scale-up and direct design purposes. Design/methodology/approach The slow pyrolysis experimental system, a batch of small-scale constant-pressure bomb for allothermic conversion processes, is presented. A DEM numerical model has been implemented by means of a modified OpenFOAM solver. The fast pyrolysis experimental system and a lab scale screw reactor designed for biomass fast pyrolysis conversion are also presented along with a 1D numerical model to represent its operation. The model which is developed for continuous stationary feeding conditions and based on a four-parallel reaction chemical framework is presented in detail. Findings The slow pyrolysis numerical results are compared with experimental data in terms of both gaseous species production and reduction of the bed height showing good predictive capabilities. Fast pyrolysis numerical results have been compared to the experimental data obtained from the fast pyrolysis process of spruce wood pellet. The comparison shows that the chemical reaction modeling based on a Gaussian DAEM is capable of giving results in very good agreement with the bio-oil yield evaluated experimentally. Originality/value As general results of the proposed activities, a mixed experimental and numerical approach has demonstrated a very good potential in developing design tools for pyrolysis development.

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

“…Zhu et al [596] simulated the fluid flow in a horizontal screw decanter centrifuge as well as the solid concentration distribution. They [597] reported that the 3D unsteady computation with a moving mesh is effective in studying the solid concentration distributions in a fast pyrolysis screw reactor.…”

Comparison of Combustion Models for Lifted Hydrogen Flames within RANS Framework

“…Hydrogen allows a useful way of storing the surplus power generated by photovoltaics and wind [7]. Moreover, in place of combustion [8,9], the gasification of waste, biomass, and coal [10,11] provides a useful procedure for efficient and clean conversion, whereby the product synthesis gas (syngas) contains rather considerable portions of hydrogen. Furthermore, there is a developing tendency in hydrogen production using nuclear energy [12].…”

Validation of Combustion Models for Lifted Hydrogen Flame

“…1b, one can see that oxygen penetrates into the fuel jet along the lift-off distance, and, is, then, rapidly consumed by the combustion reactions starting at the flame root, causing a local oxygen depleted zone. Inspecting the data of Wu et al [6] one can deduce that the measured lift-off heights in their dependence to the temperature of the coflow-stream can be represented by the following relationship with a quite good accuracy Table 4, for different coflow temperatures.…”

“…Hydrogen offers an attractive alternative for storing excess energy in power generation from photovoltaics and wind energy. Furthermore, instead of combustion [5] the gasification of waste, biomass and coal [6] offers good possibilities for efficient and clean power generation. The so-called synthesis gas (syngas), which results as the product of gasification, contains, in addition to carbon monoxide and small fractions of methane, rather significant amounts of hydrogen.…”