Study of multiphase flow useful to understand scaleup of coal liquefaction reactors. 1981-1984 final report

Technical Report · Sat Sep 01 04:00:00 EDT 1984

OSTI ID:6460220

Knickle, H N

Research over a three year time span involved the study of multiphase flow useful to understanding the scaleup of coal liquefaction reactors. We attempted to establish the flow patterns and their boundaries in which a direct coal liquefaction, large diameter, bubble column operates. A flow map has been proposed in which coal slurry properties can be input to determine the flow pattern boundaries at reactor operating conditions. Gas holdup and bubble diameters have been measured under different conditions of gas and liquid flow rate. These have been used to determine interfacial area in bubble columns. An equation for the estimation of interfacial area in the bubble-slug flow pattern has been proposed. It has also been established that gas holdup and thus interfacial area depends strongly on the gas distribution in the column. Porous plate gas distributors can yield gas holdups twice as large as sieve plate distributors. Measurements using aqueous solutions (carboxy methyl cellulose) indicate that non-Newtonian solutions can affect the gas holdup, the transition from bubble to bubble-slug flow, and the interfacial area. These experiments have been analyzed and equations for gas holdup and interfacial area have been proposed. Analysis of these experiments involved modelling the bubble slug flow pattern with limited success. In highly viscous systems slug flow can reappear and modelling results for this pattern under highly viscous conditions were successful resulting in an equation for the shear rate in the bubble column. This last model also predicted gas holdup with reasonable accuracy. 167 references.

• Research Organization: Rhode Island Univ., Kingston (USA). Dept. of Chemical Engineering
• DOE Contract Number: FG22-81PC40797
• OSTI ID: 6460220
• Report Number(s): DOE/PC/40797-T4; ON: DE85001312
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
42 ENGINEERING
420400 -- Engineering-- Heat Transfer & Fluid Flow
BUBBLES
CHEMICAL REACTORS
COAL LIQUEFACTION
DATA ANALYSIS
EQUATIONS
FLUID FLOW
FLUID MECHANICS
LIQUEFACTION
MATHEMATICAL MODELS
MECHANICS
MULTIPHASE FLOW
THERMOCHEMICAL PROCESSES