Process for heating coal-oil slurries [electronic resource].

Published:: Washington, D.C. : United States. Dept. of Energy, 1984.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Additional Creators:: United States. Department of Energy and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

Controlling gas to slurry volume ratio to achieve a gas holdup of about 0.4 when heating a flowing coal-oil slurry and a hydrogen containing gas stream allows operation with virtually any coal to solvent ratio and permits operation with efficient heat transfer and satisfactory pressure drops. The critical minimum gas flow rate for any given coal-oil slurry will depend on numerous factors such as coal concentration, coal particle size distribution, composition of the solvent (including recycle slurries), and type of coal. Further system efficiency can be achieved by operating with multiple heating zones to provide a high heat flux when the apparent viscosity of the gas saturated slurry is highest. Operation with gas flow rates below the critical minimum results in system instability indicated by temperature excursions in the fluid and at the tube wall, by a rapid increase and then decrease in overall pressure drop with decreasing gas flow rate, and by increased temperature differences between the temperature of the bulk fluid and the tube wall. At the temperatures and pressures used in coal liquefaction preheaters the coal-oil slurry and hydrogen containing gas stream behaves essentially as a Newtonian fluid at shear rates in excess of 150 sec.sup. -1. The gas to slurry volume ratio should also be controlled to assure that the flow regime does not shift from homogeneous flow to non-homogeneous flow. Stable operations have been observed with a maximum gas holdup as high as 0.72.

Report Numbers:

E 1.99:us 4424108
us 4424108

Other Subject(s):

Process Heating Coal-Oil Slurries Controlling Gas Slurry Volume Ratio Achieve Gas Holdup Heating Flowing Coal-Oil Slurry Hydrogen Containing Gas Stream Allows Operation Virtually Coal Solvent Ratio Permits Operation Efficient Heat Transfer Satisfactory Pressure Drops Critical Minimum Gas Flow Rate Coal-Oil Slurry Depend Numerous Factors Coal Concentration Coal Particle Size Distribution Composition Solvent Including Recycle Slurries Type Coal Efficiency Achieved Operating Multiple Heating Zones Provide Heat Flux Apparent Viscosity Gas Saturated Slurry Operation Gas Flow Rates Below Critical Minimum Results Instability Indicated Temperature Excursions Fluid Tube Wall Rapid Increase Decrease Overall Pressure Drop Decreasing Gas Flow Rate Increased Temperature Differences Temperature Bulk Fluid Tube Wall Temperatures Pressures Coal Liquefaction Preheaters Coal-Oil Slurry Hydrogen Containing Gas Stream Behaves Essentially Newtonian Fluid Shear Rates Excess 150 1 Gas Slurry Volume Ratio Controlled Assure Flow Regime Shift Homogeneous Flow Non-Homogeneous Flow Stable Operations Observed Maximum Gas Holdup 72 Coal Particle Coal-Oil Slurry Coal-Oil Slurry Coal-Oil Slurry Flow Regime Temperature Difference Tube Wall Tube Wall Volume Ratio Volume Ratio Heat Flux Size Distribution Flow Rates Pressure Drop Pressure Drop Gas Flow Gas Flow Gas Flow Gas Stream Gas Stream Heat Transfer Flow Rate Flow Rate Flow Rate Coal Liquefaction Particle Size Containing Gas Containing Gas Temperature Differences Efficient Heat Temperature Excursion Permits Operation Multiple Heating Controlling Gas Hydrogen Containing Hydrogen Containing Rapid Increase Shear Rate Stable Operation Increased Temperature Newtonian Fluid Allows Operation

Note:

Published through SciTech Connect.
01/03/1984.
"us 4424108"
"US patent application 06/337,301"
Braunlin, Walter A.; Gorski, Alan; Jaehnig, Leo J.; Moskal, Clifford J.; Naylor, Joseph D.; Parimi, Krishnia; Ward, John V.
Pittsburgh and Midway Coal
SRC International Inc.

Funding Information:

AC01-76ET10104
AC05-78OR03055

View MARC record | catkey: 14716887