Abstract
This study addresses the need to model bubble flow in a fluidized bed using a probabilistic approach, which includes intrinsic bubble flow randomness. It is shown that the proposed probabilistic predictive model (PPM) overcomes the limitations of deterministic correlations, commonly used to describe bubble dynamics in high-density (above 2000 kg/m3) sand-beds of Type B particles of the Geldart classification. It is proven that a PPM can describe the relationship between bubble axial chord and bubble rise velocity using minimum and maximum behavioral bands. This probabilistic model, which applies to a wide range of operating conditions, as shown in the present study, can be considered applicable to single bubbles injected at incipient fluidization, as well as to bubbly beds with and without loaded biomass pellets.
Highlights
The gasification of biomass in a fluidized bed is an efficient and fast way to transform agricultural waste and other biomass sources into synthesis gas, known as syngas [1,2,3].While the collection of tar formed and the particles are potential issues, as has been well documented by others [4,5,6,7], adequate cyclones and filters in gasifiers can help in providing clean green energy, since synthesis gas can be used to produce liquid fuels, chemicals of high value, and other forms of energy vectors
The use of coarse sand particles of the Geldart Type B [8] in dense phase fluidized beds is adequate for gasifying biomass, given that it simplifies the separation of gases from ash and char
The use of this approach can have a considerable impact on the nature of two-phase fluidized bed gasifier unit models, Processes 2021, 9, 1092 accounting for both heterogenous and homogeneous reactions as follows: (a) chemical species balances in the dense phase; (b) chemical species balances in the gas phase based on the probabilistic predictive model (PPM); and (c) link between dense and bubble phases accounting for chemical species transport via bubble interfaces, as determined by the PPM
Summary
The gasification of biomass in a fluidized bed is an efficient and fast way to transform agricultural waste and other biomass sources into synthesis gas, known as syngas [1,2,3]. Regarding single bubble motion in a fluidized bed, it has been reported [10,11,12] that a fluidized bed can be represented using a bubbling gas in a low viscosity liquid These authors proposed a model to correlate the air bubble sizes with their rise velocity or BRV. Type B particles of the Geldart classification, and for the scale-up of sand fluidized beds used in the production of syngas from agricultural waste This represents a new way of modelling flow phenomena in fluidized bed reactors, where the intrinsic randomness of the bubble flow is included in the bubble phase description. The use of this approach can have a considerable impact on the nature of two-phase fluidized bed gasifier unit models, Processes 2021, 9, 1092 accounting for both heterogenous and homogeneous reactions as follows: (a) chemical species balances in the dense phase; (b) chemical species balances in the gas phase based on the PPM; and (c) link between dense and bubble phases accounting for chemical species transport via bubble interfaces, as determined by the PPM
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
