Process for heating coal oil slurries

Details Process for heating coal oil slurries Process for heating coal oil slurries

C - Chemistry, Metallurgy

10

G

196/5.8

C10G 1/06 (2006.01)

Patent

CA 1186259

PROCESS FOR HEATING COAL OIL SLURRIES ABSTRACT Controlling gas to slurry volume ratio when heating a flowing coal-oil slurry and a hydrogen containing gas stream allows operation with virtually any coal to sol- vent ratio. Controlling the gas to slurry volume ratio to achieve a gas holdup of about 0.4, and preferably 0.38, permits operation with efficient heat transfer and satis- factory 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 dis- tribution, 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. Appli- cants have further discovered that 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-1. The gas to slurry volume ratio should also be controlled to assure that the flow regime does not shift from homogeneous flow (bubble, dispersed bubble, elongated bubble, and the like) to non-homogeneous flow (stratified, slugging, plug, and the like). Although applicants have observed stable operations with a maximum gas holdup as high as 0.72, applicants prefer to operate with a gas holdup no greater than 0.68.

395011

Affiliated with

Also associated with

Rating

Process for heating coal oil slurries does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for heating coal oil slurries, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for heating coal oil slurries will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFCA-PAI-O-1191544