New theory is developed to define the parameters controlling the pyrolysis rate of single particles. It is shown that the relative importance of internal and external heat transfer and of the, intrinsic (first order) pyrolysis kinetics can be determined from the Biot number (hR/K) and, depending on
Heat transfer mechanisms and multi-step kinetics in the ablative pyrolysis of cellulose
โ Scribed by Colomba Di Blasi
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 844 KB
- Volume
- 51
- Category
- Article
- ISSN
- 0009-2509
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โฆ Synopsis
A new model is presented of a cellulosic cylinder which thermally degrades, because of a high pressure contact of its bottom side against a hot spinning disk.From the chemical point of view, the solid undergoes, in the first place, a dopolymerization process with the formation of a molten active intermediate which, subsequently, vaporizes or gives rise to the formation of chars and gases.From the physical point of view, the model accounts for transport phenomena through the porous solid and the molten layer (adjacent to the hot plate) whose properties and size val3~ during thermal degradation.The dependence of process dynamics, ablation rate, thickness of the reaction zone and product yields on the plate temperature and applied pressure are simulated. Some important experimental findings are confu-med.
๐ SIMILAR VOLUMES
The firebox of a pyrolysis furnace is divided into zones and the temperature distribution is generated. Heat transfer by radiation and convection is considered. The location of the burners in the oven walls is explicitly accounted for. Absorption and emission of radiation by the flue gas are calcula