Computational analysis of influence of particle size, oxygen concertation, and furnace temperature on the ignition characteristics of pulverized high ash and high moisture coal particle

The wear of scraper conveyor chute causes both significant economic and environmental losses by shortening the service life. The life of the chute under coal abrasive wear situations is primarily decided by operating conditions and the materials properties. The comprehensive analysis of the influence factors had not been studied before. In this paper, the Plackett-Burman design (PBD) method was used to screen the main influence factors and a regression equation was developed to predict the wear loss. The steel was tested on a modified pin-on-disk apparatus in which coal abrasive was filled in the disk. The influence factors included water content, gangue content, coal particle size, Hardgrove Grindability-Index (HGI) of the coal, normal load, and scraper chain speed. The results of the investigation suggested that the significance of water content, normal load, and gangue content on wear loss was relatively higher than the HGI of coal, scraper chain speed, and coal particle size. The wear loss increased with the increase of water content, gangue content, normal load, and coal particle size while it decreased as increase in HGI of the coal and scraper chain speed. Based on the significance of the parameters, the regression equations were derived and verified further with a number of test cases. Optical microscope studies revealed the main wear mechanism of the chute was mainly micro-cutting and corrosive wear and accompanied by fatigue fracture.

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Numerical Simulation of Mutually Embedded Settlement in Miscellaneous Fill

Advances in Civil Engineering ◽

10.1155/2020/6695661 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Fuhai Zhang ◽

Zhengrong Liu ◽

Yu Chen ◽

Liang Chen ◽

Xianwen Huang ◽

...

Keyword(s):

Particle Size ◽

Contact Surface ◽

Theoretical Foundation ◽

Soft Soil ◽

Horizontal Distribution ◽

Composite Foundation ◽

Contact Friction ◽

High Moisture ◽

Interface Friction ◽

Embedded Development

Embedding soft soil particles with high moisture content into miscellaneous fill with large pores under overlying loads is easy. It produces mutually embedded settlement, which is an important component of total foundation settlement during calculation. In this study, influences of interface friction on mutually embedded settlement, particle displacement, pore and contact characteristics, and mutually embedded development laws were analysed by using the particle flow method. Research results demonstrate that mutually embedded settlement decreases first and then stabilizes with the increase in contact friction factor and continuously attenuates with normal stiffness. Under the loads, particles at the contact surface move downward and squeeze surrounding particles laterally, thus causing particles to slide at the miscellaneous fill channel upward. Consequently, porosity of particles in miscellaneous fill channel increases. The force chain at the contact surface inclines around, while that at the miscellaneous fill channel presents approximately horizontal distribution. Compared with 35 and 45 mm particles, the mutually embedded settlement of 15 and 25 mm particles is slightly increased with loads. Particle size can relieve the influences of loads on mutual embedding. When particle size is larger than 25 mm, loads can significantly influence mutual embedding. Research conclusions can provide a reasonable theoretical foundation for calculating or predicting settlement of miscellaneous fill-soft soil composite foundation.

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Computational Analysis of Displacement of Particles with Given Size on the Nonstationary Bulging Membrane as a Theoretical Model of Membrane Fouling

Chemical and Process Engineering ◽

10.2478/cpe-2013-0010 ◽

2013 ◽

Vol 34 (1) ◽

pp. 109-119 ◽

Cited By ~ 4

Author(s):

Jakub M. Gac ◽

Leon Gradoń

Keyword(s):

Particle Size ◽

Theoretical Model ◽

Membrane Fouling ◽

Computational Analysis ◽

New Production ◽

Mean Velocity ◽

Production Methods ◽

The Mean ◽

Particle Behaviour ◽

Diffusive Behaviour

Abstract A simple model of behaviour of a single particle on the bulging membrane was presented. As a result of numerical solution of a motion equation the influence of the amplitude and frequency of bulging as well as the particle size on particle behaviour, especially its downstream velocity was investigated. It was found that the bulging of a membrane may increase the mean velocity of a particle or reinforce its diffusive behaviour, dependeing on the permeation velocity. The obtained results may help to design new production methods of highly fouling-resistant membranes.

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The effect of coal particle size on pyrolysis and steam gasification

Fuel ◽

10.1016/s0016-2361(01)00153-3 ◽

2002 ◽

Vol 81 (5) ◽

pp. 531-537 ◽

Cited By ~ 58

Author(s):

S. Hanson ◽

J.W. Patrick ◽

A. Walker

Keyword(s):

Particle Size ◽

Coal Particle ◽

Steam Gasification

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Computational Study of 16 kWth Furnace Cofired Using Pulverized Bituminous Coal and Liquified Petroleum Gas Operated in Un-Staged and Air-Staged Conditions

Journal of Energy Resources Technology ◽

10.1115/1.4048868 ◽

2020 ◽

Vol 143 (8) ◽

Author(s):

Nitesh Kumar Sahu ◽

Mayank Kumar ◽

Anupam Dewan

Keyword(s):

Particle Size ◽

Coal Particle ◽

Bituminous Coal ◽

Computational Study ◽

Pearson Correlation ◽

Turbulence Models ◽

The Other ◽

Test Facility ◽

Measured Temperature ◽

Inlet Swirl

Abstract This paper presents a computational study on air-fuel combustion of bituminous coal and liquified petroleum gas (LPG) in a 16 kWth test facility with a coflow-swirl burner. The performance of three turbulence models is investigated for the furnace operated under both air-staged and un-staged conditions by comparing their predictions with the reported measurements of temperature and species concentrations. This comparison shows that the shear stress transport (SST) k–ω model and SST k–ω model with low-Re correction predict the profiles of temperature and species concentrations reasonably well, but significantly underpredict the temperature in the furnace core at axial locations away from the burner. On the other hand, the transition SST k–ω model provides better overall congruency with the measured temperature and species concentrations when compared with the other turbulence models used, as indicated by relatively higher values of the Pearson correlation coefficient at locations away from the burner. The present high-fidelity computational model developed is also capable of accurately simulating the effect of coal particle size on the furnace environment, which is verified by the match between the computational predictions and the experimental results for two different sized coal samples. The model is also used to investigate the effect of coal particle size on the internal recirculation zone (IRZ) and the reattachment length (LR) for the same inlet swirl number (SN). A decrease of nearly 50% in the coal sample size results in the increase of LR and IRZ length by 20% and 82.6%, respectively.

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