| 1. |
- Chen, Tao, et al.
(författare)
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CFD-DEM simulation of biomass pyrolysis in fluidized-bed reactor with a multistep kinetic scheme
- 2020
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 13:20
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Tidskriftsartikel (refereegranskat)abstract
- The pyrolysis of biomass in a fluidized-bed reactor is studied by a combination of a CFD-DEM algorithm and a multistep kinetic scheme, where fluid dynamics, heat and mass transfer, particle collisions, and the detailed thermochemical conversion of biomass are all resolved. The integrated method is validated by experimental results available in literature and a considerable improvement in predicting the pyrolysis product yields is obtained as compared to previous works using a two-fluid model, especially the relative error in the predicted tar yield is reduced by more than 50%. Furthermore, the evolution of light gas, char and tar, as well as the particle conversion, which cannot easily be measured in experiments, are also revealed. Based on the proposed model, the influences of pyrolysis temperature and biomass particle size on the pyrolysis behavior in a fluidized-bed reactor are comprehensively studied. Numerical results show that the new algorithm clearly captures the dependence of char yield on pyrolysis temperature and the influence of heating rate on light gas and tar yields, which is not possible in simulations based on a simplified global pyrolysis model. It is found that, as the temperature rises from 500 to 700 °C, the light gas yield increases from 17% to 25% and char yield decreases from 22% to 14%. In addition, within the tested range of particle sizes (<1 mm), the impact on pyrolysis products from particle size is relatively small compared with that of the operating temperature. The simulations demonstrate the ability of a combined Lagrangian description of biomass particles and a multistep kinetic scheme to improve the prediction accuracy of fluidized-bed pyrolysis.
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| 2. |
- Huang, Hongyun, et al.
(författare)
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The 2022 yearbook of neurorestoratology
- 2023
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Ingår i: JOURNAL OF NEURORESTORATOLOGY. - : Tsinghua University Press. - 2324-2426. ; 11:2
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Forskningsöversikt (refereegranskat)abstract
- There was much progress in the field of Neurorestoratology in the year of 2022. It included highlighting advances in understanding the pathogenesis of neurological diseases, neurorestorative mechanisms, and clinical treatments as compiled in the 2022 yearbook of Neurorestoratology. There is still controversy about whether amyloid b-protein and tau protein deposition are the reasons for or the results of Alzheimer's disease (AD) pathology. The fabricated images in important key articles that speculated on the reasons for AD pathogenesis were found. Cholinergic deficiency and decrease or loss in strength of glutamatergic synapse, limited or failing bidirectional cholinergic upregulation in early cognitive impairment, or progressive posterior-to-anterior cortical cholinergic denervation could result in the appearance of AD. Exploration of neurorestorative mechanisms were found in more detail ways in neuromodulation, immunomodulation, neurogenesis, neural network or circuitry reconstruction, neuroprotection, nervous structural repair, and neuroplasticity. Several kinds of cell therapies for neurological diseases showed neurorestorative effects in open-label and/or non-randomized clinical studies or trials. However, mesenchymal stromal cells and mononuclear cells did not demonstrate neurorestorative effects or improve the quality of life for patients with neurodegenerative diseases or neurotrauma including stroke, spinal cord injury (SCI), and amyotrophic lateral sclerosis in randomized, double-blind, placebo-controlled clinical trials (RDPCTs). Clinical treatments through neurostimulation/neuromodulati on and the brain-computer/ machine interface yielded positive results in AD, Parkinson's disease, stroke, SCI, cerebral palsy, and other diseases in RDPCTs. Neurorestorative surgery, pharmaceutical neurorestorative therapy and other interventions have demonstrated neurorestorative effects for various considered incurable neurological diseases in RDPCTs. Thus, this year, additional guidelines, assessment scales, and standards were set up or revised. These included guidelines of clinical neurorestorative treatments for brain trauma (2022 China version), clinical cell therapy guidelines for neurorestoration (IANR/CANR 2022), SCI or dysfunction quality of life rating scale (SCIDQLRS) (IANR 2022 version). Neurorestorative effects of varying therapeutic stra-tegies with higher standards of evidence-based medicine are now benefiting patients with currently incurable neurological diseases. Hopefully some of them may become routine therapeutic interventions for patients with these diseases in the near future.
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| 3. |
- Tao, Chen, 1989, et al.
(författare)
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Pyrolysis Simulation of Thermally Thick Biomass Particles Based on a Multistep Kinetic Scheme
- 2020
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 34:2, s. 1940-1957
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Tidskriftsartikel (refereegranskat)abstract
- A new Eulerian-Lagrangian pyrolysis model is developed in the thermally thick regime to study the pyrolysis yields of large biomass particles based on a multistep kinetic scheme. The integrated pyrolysis model is first validated with experiments of centimeter-sized wood particles under both low- and high-temperature conditions. Good agreement is obtained between simulations and experimental measurements for low-temperature (375 and 470 °C) pyrolysis. However, for 800 °C pyrolysis, the predicted char, tar, and gas yields are not as accurately predicted as those of the low-temperature situation, while the overall gas and tar yields show an improvement when secondary tar decomposition is considered. Moreover, simulation results reveal that different sized particles generate similar char, tar, and gas yields, which account for about 30, 52, and 12% of the initial mass, respectively. Besides, a significant increase of the gas yield (∼70%) and a moderate decrease of the char yield (∼25%) are observed when the pyrolysis temperature increases from 400 to 700 °C, while the tar yield only changes slightly with first an increasing trend and then a decreasing trend with raising the pyrolysis temperature. The biomass type also has an important impact on both light gas and tar yields as a result of different components in each particle. Finally, effects of tar cracking and alkali metal catalyst on pyrolysis are also discussed.
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