Hydrodynamics and heat transfer related to coal liquefaction preheaters

Technical Report · Fri Apr 01 04:00:00 EST 1983

OSTI ID:6655848

Bishop, A A

There is a sufficient data base to explore pressure drop and heat transfer for a non-phase change, Newtonian liquid-gas two-component mixture in vertical upward and downward flow. However, new data will help to clarify the role played by the U-tube geometry. The current state of two-component boiling heat transfer and pressure drop in a vertical U-tube geometry is deficient for Newtonian liquid-gas mixtures and virtually non-existent for non-Newtonian liquid-gas mixtures. An understanding of flow and temperature instabilities observed in coal liquefaction preheaters might best be approached using traditional analyses. The instability reported in the Ft. Lewis plant is similar to a static type instability caused by a multi-valued ..delta..p versus flow relationship observed previously for many types of two-phase gas-liquid flow systems. In a typical coal liquefaction pilot plant, the coal slurry is in laminar flow and the multivalued pressure drop versus flow relationship is generated by drag reduction; i.e., a condition where the two-phase pressure drop is less than the single phase pressure drop. Accurate and reliable rheological analysis of two-phase non-Newtonian liquid-gas flowing mixtures should be supported by in depth data and analysis obtained for single phase non-Newtonian flow systems. However, in the case of high swelling coal slurries, it will be extremely difficult to obtain single phase rheological experimental data in the high swelling high temperature region. Because of this limitation, physical models must be developed to extend the rheological data such as the apparent viscosity, flow index and consistency index, to the high swelling region. A second approach is to model the rheology directly from the two-phase system. However, this method requires that suitable non-Newtonian correlations and/or analysis be used, otherwise the properties, such as apparent viscosity, could be grossly underpredicted. 56 references, 18 figures, 9 tables.

• Research Organization: Pittsburgh Univ., PA (USA). Dept. of Chemical and Petroleum Engineering
• DOE Contract Number: AC22-81PC41030
• OSTI ID: 6655848
• Report Number(s): DOE/PC/41030-T2; ON: DE84015829
• 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
COAL LIQUEFACTION
CORRELATIONS
DATA
DRAG
ENERGY TRANSFER
EXPERIMENTAL DATA
FLUID FLOW
FLUID MECHANICS
FUNCTIONAL MODELS
HEAT TRANSFER
HEATERS
INFORMATION
INSTABILITY
LIQUEFACTION
MATHEMATICAL MODELS
MECHANICS
NUMERICAL DATA
PILOT PLANTS
PRESSURE DROP
RHEOLOGY
SRC PROCESS
THERMOCHEMICAL PROCESSES
TWO-PHASE FLOW
VISCOSITY