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Title: Process for heating coal-oil slurries

Abstract

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.more » 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.« less

Inventors:
 [1];  [2];  [3];  [4];  [5];  [6];  [7]
  1. Spring, TX
  2. Lovington, NM
  3. New Orleans, LA
  4. Oklahoma City, OK
  5. Houston, TX
  6. Allison Park, PA
  7. Arvada, CO
Issue Date:
Research Org.:
Pittsburgh and Midway Coal; SRC International Inc.
Sponsoring Org.:
USDOE
OSTI Identifier:
864824
Patent Number(s):
4424108
Application Number:
06/337,301
Assignee:
Pittsburg & Midway Coal Mining Co. (Englewood, CO)
DOE Contract Number:  
AC01-76ET10104; AC05-78OR03055
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
process; heating; coal-oil; slurries; controlling; gas; slurry; volume; ratio; achieve; holdup; flowing; hydrogen; containing; stream; allows; operation; virtually; coal; solvent; permits; efficient; heat; transfer; satisfactory; pressure; drops; critical; minimum; flow; rate; depend; numerous; factors; concentration; particle; size; distribution; composition; including; recycle; type; efficiency; achieved; operating; multiple; zones; provide; flux; apparent; viscosity; saturated; rates; below; results; instability; indicated; temperature; excursions; fluid; tube; wall; rapid; increase; decrease; overall; drop; decreasing; increased; differences; bulk; temperatures; pressures; liquefaction; preheaters; behaves; essentially; newtonian; shear; excess; 150; -1; controlled; assure; regime; shift; homogeneous; non-homogeneous; stable; operations; observed; maximum; 72; coal particle; coal-oil slurry; flow regime; temperature difference; tube wall; volume ratio; heat flux; size distribution; flow rates; pressure drop; gas flow; gas stream; heat transfer; flow rate; coal liquefaction; particle size; containing gas; temperature differences; efficient heat; temperature excursion; permits operation; multiple heating; controlling gas; hydrogen containing; rapid increase; shear rate; stable operation; increased temperature; newtonian fluid; allows operation; /208/

Citation Formats

Braunlin, Walter A, Gorski, Alan, Jaehnig, Leo J, Moskal, Clifford J, Naylor, Joseph D, Parimi, Krishnia, and Ward, John V. Process for heating coal-oil slurries. United States: N. p., 1984. Web.
Braunlin, Walter A, Gorski, Alan, Jaehnig, Leo J, Moskal, Clifford J, Naylor, Joseph D, Parimi, Krishnia, & Ward, John V. Process for heating coal-oil slurries. United States.
Braunlin, Walter A, Gorski, Alan, Jaehnig, Leo J, Moskal, Clifford J, Naylor, Joseph D, Parimi, Krishnia, and Ward, John V. Tue . "Process for heating coal-oil slurries". United States. https://www.osti.gov/servlets/purl/864824.
@article{osti_864824,
title = {Process for heating coal-oil slurries},
author = {Braunlin, Walter A and Gorski, Alan and Jaehnig, Leo J and Moskal, Clifford J and Naylor, Joseph D and Parimi, Krishnia and Ward, John V},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1984},
month = {1}
}

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