Process for heating coal-oil slurries

Patent · Tue Jan 03 04:00:00 EST 1984

OSTI ID:7013632

Braunlin, W A; Gorski, A; Jaehnig, L J; Moskal, C J; Naylor, J D; Parimi, K; Ward, J V

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 [minus]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. 29 figs.

• Research Organization: Pittsburgh and Midway Coal; SRC International Inc.
• DOE Contract Number: AC01-76ET10104; AC05-78OR03055
• Assignee: Pittsburg Midway Coal Mining Co., Englewood, CO (United States)
• Patent Number(s): A; US 4424108
• Application Number: PPN: US 6-337301
• OSTI ID: 7013632
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010405* -- Coal
Lignite
& Peat-- Hydrogenation & Liquefaction
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
CHEMICAL REACTORS
COAL
COAL LIQUEFACTION
COAL LIQUIDS
CONCENTRATION RATIO
CONTROL
DISPERSIONS
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL SLURRIES
FUELS
HEATING
HYDROGENATION
LIQUEFACTION
LIQUIDS
MATERIALS
MIXTURES
PROCESS CONTROL
SLURRIES
SUSPENSIONS
THERMOCHEMICAL PROCESSES