Simulation of the Agro-Biomass(Olive Kernel) Fast Pyrolysis in a Wire Mesh Reactor Considering Intra-Particle Radial and Temporal Distribution of Products

Author(s):  
Theodoros Damartzis ◽  
Margaritis Kostoglou ◽  
Anastasia Zabaniotou

In the present study, a model for the fast pyrolysis of a spherical biomass particle has been developed. The model admits the generation of data which are not accessible experimentally such as the intra-particle temperature and concentration distribution. Simulations have been carried using data from the reactor as well as from literature and the effects of the heating rate and the particle size have been examined. The kinetic model is coupled with a heat transfer model. The reaction kinetic constants have been chosen in order to match the theory to the data taken from experiments carried out in a laboratory wire mesh reactor, for a temperature range from 573 K to 873 K and a heating rate of 200 K/s. Pyrolysis temperature and product distribution profiles in both spatial and temporal directions throughout the particle are presented. The effects of the particle size and the reactor's heating rate in the final pyrolysis products and temperature are shown and discussed. Simulations were carried out using Matlab and the model has been validated against the experimental results. The heating rate, which is an important operating condition in thermal processes, seems to have a positive effect on the biomass conversion to gaseous and liquid products, an increase of the first resulting to an increase of the second. Particle size was found to have a negative effect on pyrolysis conversion as larger particles tend to give higher char yields. For the particular experimental system analyzed here, it seems that the radial non-uniformity is not very large and acceptable results can also be taken using a lumped particle model. Validation of the model with experimental data showed great accordance, thus the model could be used for the prediction of final pyrolysis yields and temperatures.

2019 ◽  
Vol 132 ◽  
pp. 486-496 ◽  
Author(s):  
Bo Wang ◽  
Fanfan Xu ◽  
Peijie Zong ◽  
Jinhong Zhang ◽  
Yuanyu Tian ◽  
...  

2016 ◽  
Vol 51 (1) ◽  
pp. 13-22
Author(s):  
MB Ahmed ◽  
ATMK Hasan ◽  
M Mohiuddin ◽  
M Asadullah ◽  
MS Rahman ◽  
...  

Objective of this work was to pyrolysis woody biomass. Experiments were carried out at 300 to 500oC. Relatively bigger particles were used. Special emphasis was given to investigate the effects of heating rate and heating up time of the central mass of the particles on the product distribution. Surface temperature reached to the reactor set temperature immediately while the temperature at the central part was as low as 50oC. The center temperature gradually increased to the final temperature within 3 to 8 minutes, depending on the wood types and the reactor set temperature. For ipil-ipil wood the heating rate of the central mass was much faster than krishnachura and koroi woods, and thus the heating up time was lower. Ipil-ipil wood was experienced higher yield (65%) even at lower reactor temperature 300oC with particle temperature 450oC. In the case of krishnachura and koroi woods, the bio-oil yields were lower under the same condition due to the heating rates of the central parts were much slower. Further researchon different biomasses may be necessary to demonstrate overall process.Bangladesh J. Sci. Ind. Res. 51(1), 13-22, 2016


2007 ◽  
Vol 7 (20) ◽  
pp. 5391-5400 ◽  
Author(s):  
K. M. Nissen ◽  
K. Matthes ◽  
U. Langematz ◽  
B. Mayer

Abstract. We introduce the improved Freie Universität Berlin (FUB) high-resolution radiation scheme FUBRad and compare it to the 4-band standard ECHAM5 SW radiation scheme of Fouquart and Bonnel (FB). Both schemes are validated against the detailed radiative transfer model libRadtran. FUBRad produces realistic heating rate variations during the solar cycle. The SW heating rate response with the FB scheme is about 20 times smaller than with FUBRad and cannot produce the observed temperature signal. A reduction of the spectral resolution to 6 bands for solar irradiance and ozone absorption cross sections leads to a degradation (reduction) of the solar SW heating rate signal by about 20%. The simulated temperature response agrees qualitatively well with observations in the summer upper stratosphere and mesosphere where irradiance variations dominate the signal. Comparison of the total short-wave heating rates under solar minimum conditions shows good agreement between FUBRad, FB and libRadtran up to the middle mesosphere (60–70 km) indicating that both parameterizations are well suited for climate integrations that do not take solar variability into account. The FUBRad scheme has been implemented as a sub-submodel of the Modular Earth Submodel System (MESSy).


2015 ◽  
Vol 113 ◽  
pp. 557-563 ◽  
Author(s):  
Jacek Grams ◽  
Michał Niewiadomski ◽  
Agnieszka M. Ruppert ◽  
Witold Kwapiński

2015 ◽  
Vol 76 (5) ◽  
Author(s):  
N. Aniza ◽  
S. Hassan ◽  
M. F. M. Nor ◽  
K. E. Kee ◽  
Aklilu T.

Thermal degradation of Poultry Processing Dewatered Sludge (PPDS) was studied using thermogravimetric analysis (TGA) method. The effect of particle size on PPDS samples and operational condition such as heating rates were investigated. The non-isothermal TGA was run under a constant flow of oxygen at a rate of 30 mL/min with temperature ranging from 30ºC to 800ºC. Four sample particle sizes ranging between 0.425 mm to 2 mm, and heating rate between 5 K/min to 20 K/min were used in this study. The TGA results showed that particle size does not have any significant effect on the thermogravimetry (TG) curves at the initial stage, but the TG curves started to separate explicitly at the second stage. Particle size may affect the reactivity of sample and combustion performance due to the heat transfer and temperature gradient. The TG and peak of derivative thermogravimetry (DTG) curves tend to alter at high temperature when heating rate is increased most likely due to the limitation of mass transfer and the delay of degradation process. 


2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Huaiying Fang ◽  
Dawei Xing ◽  
Jianhong Yang ◽  
Fulin Liu ◽  
Junlong Chen ◽  
...  

This study investigates the effect of impact velocity and particle size on crushing characteristics. We use a discrete-element method simulation and construct cohesive limestone particles with internal microinterfaces and cracks for impact crushing experimentation. The simulation model follows the same process as the impact crushing experiment. Results show that, after crushing at impact velocities of 30 and 40 m/s, the simulated particle-size distribution curve matches experimental results as closely as 95%. For different particle sizes, results are more than 90% in agreement. These results indicate the feasibility of the cohesive-particle crushing simulation model. When the particle size is 15 mm, an approximate linear relationship exists on impact velocity and crushing ratio. For a constant impact velocity, the particle size of 18 mm results in the maximum crushing ratio.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Demin Chen ◽  
Wei Long ◽  
Yanyan Li ◽  
Rui Zhang

The gas loss in sampling is the root of coalbed gas content measurement error. The pressure and particle size have a significant impact on the gas loss. Using the self-developed coal particle pneumatic pipeline transportation experimental system, this study investigated the pressure and particle size changes in the sampling pipeline. It is found that the sampling process can be divided into four stages: no flow field stage, sample outburst stage, stable conveying stage, and tail purging stage. The extreme pressure in the sampling pipeline appears at the sample outburst stage; and the pressure in the pipeline has levelled off after sharp decrease in the stable conveying stage. It is also found that the extreme pressure increases first and then decreases with the increase of particle size. The duration of outburst stage is negatively correlated with particle size, and that of stable conveying stage is positively correlated with particle size. In addition, the results show that the loss rate of 1–3 mm particles is the smallest after the test but that particles less than 1 mm increase by about two times and particles greater than 3 mm decrease by more than three times. The study also shows that the particle size distribution of coal samples is a single peak with left skew distribution, and the gas reverse circulation sampling test does not change the location of the peak but makes it higher and sharper. The single size coal sample is more likely to collide than the mixture. This study can help to advance the understanding of impact factors on gas loss during reverse circulation sampling.


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