Supercritical hydroextraction of kerogen from oil shale ores

Abstract

Water is added to reduce the hydrogen consumption in kerogen conversion. The water is not stripped from oil shale ores, instead up to 10% w/w of water is added in the kerogen conversion at 400-475° C. The recycle solvent for conversion is changed to a high boiling point fraction of the oil, with a minimum boiling point of the order of 245° C. Such repeated recycling of high boiling fraction oil with a hydrogen-donor mid-distillate will remove additional sulphur, oxygen and nitrogen. It improves the quality of the final product oil. Most of the high boiling fraction of the oil will separate from the oil shale ores, at around 450° C. and 650 psig. Then it is reduced to 250° C. at 100 psig before distillation. Such column operates at around 10 to 250 psig, but preferably 50 psig. This improves thermal efficiency by avoiding the need to condense high boiling point vapors. The addition of water provides further enhancement in operating results. A consequence of recycling high boiling oil fractions is the repeated hydrogenation and hydrocracking of that fraction to increase the proportions of lower boiling fractions. This reduces the asphaltene content of the recycled and final product streams. Such is similar to hydro-visbreaking of bitumen, in which both the asphaltene fraction and the sulphur content can be halved, resulting in a product of 25-30° API gravity in a single pass. The recycling of high boiling fraction means approximately half of the product oil is repeatedly recycled. There is no recycle of the low boiling fractions. It is expected that the intractable asphaltene content of about 5% of the product oil will be in suspension under hydro-treating and hydro-cracking conditions. These are removed with the solids after a supercritical solvent wash.

1 . A method for converting ores into a product oil, comprising: 
 recirculating +245° C. fractions around through an oil shale slurry pressurized to 650 psig in a reactor heated to 450° C., depressurizing them for separation in a distillation column, and returning them with an H-donor mid-distillate.    
   
   
       2 . The method of  claim 1 , further comprising: 
 not dewatering oil shale ores contributed to said oil shale slurry; and    adding water to said reactor.    
   
   
       3 . The method of  claim 1 , further comprising: 
 operating said distillation column at about 50-psig.    
   
   
       4 . The method of  claim 1 , further comprising: 
 using clays included in a feed of oil shale ores as a catalyst that substantially increases yields of product oil.    
   
   
       5 . An ore processing plant, comprising: 
 an input for conditioning a mixture of incoming ore and a recirculating hydrogen-donor mid-distillate into a slurry;    a reactor operating under supercritical temperature and pressure conditions for converting kerogen in said ore into product oil, mid-distillates, solvents, and gas;    a distillation column connected to receive and separate said product oil, mid-distillates, solvents, and gas;    an output for product oil; and    a recycle for hydrogenation of said mid-distillates from the distillation column and for use in the input to make said slurry continuous.    
   
   
       6 . The ore processing plant of  claim 5 , further comprising: 
 a separator included with the reactor for separating product oil from the gas and solid residues; and    a recycle of solvents from the distillation column for use in supercritical solvent extraction of the oil residue in a spent oil shale.    
   
   
       7 . The ore processing plant of  claim 6 , further comprising: 
 a pulsed-wash column connected to receive solid residues and sludge from the separator and distillation column, and for using recirculating solvents to wash out product oil, and for removing and disposing of solid residues from the processing.    
   
   
       8 . The ore processing plant of  claim 5 , further comprising: 
 means for adding water to the reactor;    wherein, water is not removed from raw oil shale ore at the input before being added to said slurry.    
   
   
       9 . The ore processing plant of  claim 5 , further comprising: 
 means for using the equivalent of +245° C. fraction in the recycle.    
   
   
       10 . A continuous conversion plant for producing product oil from mined ores, comprising: 
 an input for conditioning a mixture of at least one of incoming cannel coal, and oil shale ore, and a recirculating +245° C. fraction hydrogen-donor mid-distillate into a slurry;    a reactor operating under supercritical temperature and pressure conditions of 450° C. and 650 psig for converting kerogen in said ore into product oil, mid-distillates, solvents, and gas;    a distillation column connected to receive and separate said product oil, mid-distillates, solvents, and gas;    a separator included with the reactor for separating product oil from the gas and solid residues;    a recycle of solvents from the distillation column for use in supercritical solvent extraction of the oil residue in a spent oil shale.    an output for product oil; and    a recycle for hydrogenation of +245° C. fraction mid-distillates from the distillation column and for use in the input to make said slurry continuous.    
   
   
       11 . The plant of  claim 10 , further comprising: 
 a pulsed-wash column connected to receive solid residues and sludge from the separator and distillation column, and for using recirculating solvents to wash out product oil, and for removing and disposing of solid residues from the processing; and    means for adding water to the reactor;    wherein, water is not removed from raw oil shale ore at the input before being added to said slurry.    
   
   
       12 . The plant of  claim 10 , wherein, for each ton of ore being input, 0.5 barrel per hour feed of H-donor mid-distillate is added to a recirculating carrier of about eleven barrels per hour of +245° C. mid-distillate, a 12.5 barrel per hour mix outputs about 0.75 ton of residue, and the useful products from the process include about 0.5 million cubic feet (MCF) gas, and one barrel per hour of product oil, and to balance these flows, a mid-distillate flow is taken off.