Effect of process variables on cleaning efficiency in a fluidized bed of coal and magnetite

Conference · Fri Sep 01 04:00:00 EDT 1995

OSTI ID:98693

Sahan, R A; Kozanoglu, B ^[1]

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1. Lehigh Univ., Bethlehem, PA (United States)

This investigation is concerned with the effects of coal properties and process variables, such as fluidized bed depth, superficial gas velocity, coal to magnetite feed weight ratio and processing time, on coal cleaning efficiency in a bubbling fluidized bed dry coal purifier. The coal cleaning experiments were carried out on one various size fractions of Pennsylvania`s bituminous coals, Rushton coal. Magnetite was used as the host material. Predictions of the segregation behavior of the bed under different process variables were obtained by using a theoretical model. The performance of the coal cleaning process is measured with the aid of sulfur and ash removal efficiencies as well as generalized distribution curves. Previous experimental results and those obtained in this study showed that coal particle sizes smaller than 30 mesh and larger than 140 mesh can be cleaned with high efficiency in the fluidized bed seperator. For coal particle sizes smaller than 140 mesh, bed slugging and channeling occurred due to high interparticle cohesive forces, and this resulted in a relatively poor cleaning performance. The results also indicate that the fluidized bed should be operated using shallow bed depths and processing times of 30 second or more. Experiments are also performed to determine the optimum values of superficial air velocity and the effect of feed weight ratio of coal to magnetite on cleaning performance. The theoretical model predictions agree with the results from coal cleaning experiments, showing that the cleaning efficiency is a strong function of operating conditions and bed configuration.

• OSTI ID: 98693
• Report Number(s): CONF-950640--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
BITUMINOUS COAL
CLEANING
FLUIDIZED BEDS
MAGNETITE
PARTICLE SIZE
PERFORMANCE