Modeling of continuous sewage sludge drying in a paddle dryer by coupling Markov chains and penetration theory : influence of contact area estimation

Mathieu Milhé 1 Martial Sauceau 1 Patricia Arlabosse 1
1 RAPSODEE - Centre de recherche d'Albi en génie des procédés des solides divisés, de l'énergie et de l'environnement
Abstract : Sewage sludge can be dried in paddle dryers and turned into an interesting material for energetic valorization. Matching the necessary water content at the end of the drying process for the different valorization pathways could lead to significant energy savings. However, the influence of operating conditions on process efficiency has not been studied extensively, and sludge rheology remains a scientific issue when it comes to mechanistic flow modeling. We thus developed and validated a model describing sludge flow in a continuous paddle dryer by a Markov chain. This flow model was coupled with the penetration theory, describing heat-transfer by conduction and water vaporization in an agitated packing. Both models are time-discretized and allow simulating water content and temperature profiles along the dryer at steady-state. The simulations are in good agreement with experimental water content profiles obtained on a lab-scale paddle dryer, with no adjustable parameters. Two approaches for estimating contact area between sludge and heated parts of the dryer are then compared. Our model better describes experimental data when the contact area is calculated in each cell rather than when it is considered constant and proportional to sludge holdup in the dryer. However, this latter approach could be of practical importance for simulations of large-scale installation.
Keywords : Sludge drying Paddle dryer Markov chains Penetration theory
Document type :
Conference papers
Complete list of metadatas

Cited literature [18 references]  Display  Hide  Download
https://hal-mines-albi.archives-ouvertes.fr/hal-01743222
Contributor : Lina Maria Romero Millan <>
Submitted on : Wednesday, November 7, 2018 - 4:05:43 PM
Last modification on : Wednesday, October 16, 2019 - 10:40:02 AM
Long-term archiving on : Friday, February 8, 2019 - 3:27:50 PM

File

WasteEng 2014 - Arlabosse - Fu...
Explicit agreement for this submission

Identifiers

  • HAL Id : hal-01743222, version 1

Collections

MINES-ALBI | RAPSODEE

Citation

Mathieu Milhé, Martial Sauceau, Patricia Arlabosse. Modeling of continuous sewage sludge drying in a paddle dryer by coupling Markov chains and penetration theory : influence of contact area estimation. WasteEng 2014 - 5th International Conference on Engineering for Waste and Biomass Valorisation, Aug 2014, Rio de Janeiro, Brazil. p.376-388. ⟨hal-01743222⟩

Export

BibTeX TEI DC DCterms EndNote

Share

Metrics

Record views

14

Files downloads

30

Contact

support.ccsd.cnrs.fr
hal.support@ccsd.cnrs.fr
Logo CCSD