Process for the conversion of ground hydrous lignite into a pumpable dehydrated suspension of fine-ground lignite and oil

Claim 1

A method for producing a pumpable suspension in oil of dehydrated, finely-ground lignite, said method comprising the steps of: (a) mixing hydrous, ground lignite with an oil which has a vapor pressure less than 1/2 bar at a temperature in the range of 190° to 240° C. and a diluent for the oil, said diluent being inert with respect to and miscible with the oil being effective to produce a solution with the oil which has a viscosity lower than that of the oil, being immiscible with water, and having a vapor pressure greater than 1 bar at a temperature in the range of 190° to 240° C.; (b) controlling the proportions of the lignite, of the oil and of the diluent so that the mixture, when the lignite is ground so that substantially all the particles thereof are finer than 2 mm, is a pumpable suspension; (c) grinding the lignite in the mixture so that substantially all the particles thereof are finer than 2 mm; (d) heating the suspension to a temperature in the range of 190° to 240° C.; (e) subjecting the suspension to a pressure in the range of 30 to 80 bar; (f) partially dehydrating the lignite therein by maintaining the suspension at a temperature within the range of 190° to 240° C. and at a pressure in the range of 30 to 80 bar for at least 5 minutes; (g) after the partial dehydration step, separating the suspension into a slurry of partially dehydrated lignite and oil and a liquid composed principally of water, diluent and oil; (h) separating water from the liquid of step (g) and mixing the oil and diluent which remain with the slurry of partially dehydrated lignite and oil from step (g) to produce a suspension of partially dehydrated lignite; (i) reducing the pressure of the suspension of partially dehydrated lignite to one in the range of 1 to 18 bar while maintaining the temperature thereof at one in the range of 190° to 240° C.; and (j) separating water and the diluent from the suspension of step (i), leaving a dehydrated lignite suspension in oil.

Claim 2

A method for producing a pumpable suspension in oil of dehydrated, finely-ground lignite, said method comprising the steps of: (a) mixing hydrous, ground lignite with an oil which has a vapor pressure less than 1/2 bar at a temperature in the range of 190° to 240° C. and a diluent for the oil, said diluent being inert with respect to and miscible with the oil being effective to produce a solution with the oil which has a viscosity lower than that of the oil, being immiscible with water, and having a vapor pressure greater than 1 bar at a temperature in the range of 190° to 240° C.; (b) controlling the proportions of the lignite, of the oil and of the diluent so that the mixture, when the lignite is ground so that substantially all the particles thereof are finer than 2 mm, is a pumpable suspension; (c) grinding the lignite in the mixture so that substantially all the particles thereof are finer than 2 mm; (d) heating the suspension to a temperature in the range of 190° to 240° C.; (e) subjecting the suspension to a pressure in the range of 30 to 80 bar; (f) partially dehydrating the lignite therein by maintaining the suspension at a temperature within the range of 190° to 240° C. and at a pressure in the range of 30 to 80 bar for at least 5 minutes; (g) after the partial dehydration step, separating the suspension into a slurry of partially dehydrated lignite and oil and a liquid composed principally of water, diluent and oil; (h) separating water from the liquid of step (g) and mixing the oil and diluent which remain with the slurry of partially dehydrated lignite and oil from step (g) to produce a suspension of partially dehydrated lignite; (i) reducing the pressure of the suspension of partially dehydrated lignite to one in the range of 1 to 18 bar while maintaining the temperature thereof at one in the range of 190° to 240° C.; and (j) separating water and the diluent from the suspension of step (i), leaving a dehydrated lignite suspension in oil.

Claim 6

A method as claimed in claims 1, 2, 3 or 4 wherein the oil is derived from non-refined coal hydrogenation or carbonization products.

Claim 8

A method as claimed in claims 1, 2, 3 or 4 wherein the diluent is a hydrocarbon which has, or a hydrocarbon mixture substantially all of the components of which have, a vapor pressure of 760 mm Hg at a temperature within the range of 110° to 104° C.