Investigation of two-phase flow processes in coal slurry/hydrogen heaters. Final report
Experimental and analytical results are presented for two-phase slug flow in a horizontal, transparent pipe at large diameter (6.75 in.) at high gas density (20 times the density of air at atmospheric pressure) and at liquid viscosities ranging from 1 to 1000 centipoise. The test section replicates 1 1/2 rectangular coils (40 ft by 10 ft) of a fired heater in a coal liquefaction plant. Regime transtion, pressure drop, void fraction, and slug characteristic data have been obtained for liquid superficial velocities ranging from 0.2 to 6 ft/s and gas superficial velocities ranging from 0.2 to 12 ft/s. Regime transition results have been compared with the Taitel-Dukler analytical flow regime map. The transition from stratified to slug flow, which is underpredicted by the original analysis, has been studied in particular. Comparison with the dimensionless transition criterion (gas Froude number) shows that increased liquid viscosity increases the liquid level at which the transition occurs. Pressure drop data at the transition have been used to evaluate the interfacial shear and to show that it is greater than is assumed in the Taitel-Dukler analysis. Sensitivity studies for the transition criterion and interfacial shear illustrate exactly why the transition is underpredicted on the flow regime map and how the predictions can be improved. Photos of the flow patterns illustrate the mechanism of slug formation at high viscosity compared with low viscosity. Pressure drop, void fraction, and slug characteristic results are compared with an analysis for pressure drop in slug flow, demonstrating better predictive capability of this model at large pipe size, high gas density, and high viscosity, compared with correlations from the literature. The pressure drop model is also shown to be in excellent agreement with coal liquefaction pilot plant data. 34 refs.
- Research Organization:
- Creare, Inc., Hanover, NH (USA)
- DOE Contract Number:
- AC22-85PC80028
- OSTI ID:
- 7248858
- Report Number(s):
- DOE/PC/80028-T1; ON: DE86014479
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COAL LIQUEFACTION
HEATERS
FLUID MECHANICS
PRESSURE DROP
PIPES
TWO-PHASE FLOW
CORRELATIONS
DENSITY
EXPERIMENTAL DATA
SIZE
TEST FACILITIES
VELOCITY
DATA
FLUID FLOW
INFORMATION
LIQUEFACTION
MECHANICS
NUMERICAL DATA
PHYSICAL PROPERTIES
THERMOCHEMICAL PROCESSES
010405* - Coal
Lignite
& Peat- Hydrogenation & Liquefaction