Supercritical hydro extraction of kerogen and aqueous extraction of alumina and soda ASH with a residue for portland cement production

Abstract

A method and apparatus for the extraction of hydrocarbon products, alumina and soda ash from oil shales including various amounts of such chemicals, all based on solvent extraction of most of the hydrocarbons at temperatures around 400° C. Such enables the alumina and soda ash values to be leached out with aqueous sodium carbonate leaching at reduced temperatures of around 150° C. with a corresponding reduced pressure. The soda ash monohydrate values are precipitated from the leach liquor at around 100° C. with the alumina values precipitated using Co 2 . Alternatively recycled fine aluminum trihydrate at 65° C. is used to produce alumina. Aluminum hydroxide is converted to acid alumina by an acid recycle stream that dissolves the alumina so any silica contaminant can be filtered out. Basic aluminum sulfate is then precipitated at about 200° C. and 250 PSIG for subsequent calcination at around 900° C. This produces alumina and sulphate oxide gasses are recycled via a sulphuric-acid plant.

1 . An oil-shale processing plant for extracting kerogen and outputting a pipelineable synthetic crude oil, comprising: 
 a water removing stage for taking water out of a mixture of oil shale and a recycled solvent;    a first heat exchanger connected to receive a de-watered slurry of oil shale and a recycled solvent from the water removing stage under elevated pressure, and to heat said slurry with heat extracted from a product oil to an elevated temperature;    a reactor operated over a residence time at elevated temperatures and pressures that keep said solvent in its liquid phase and produce a solubility of a kerogen in said slurry received from the heat exchanger;    an oil separator that receives said kerogen in solution of said solvent and said oil shale from the reactor, and that separates them, wherein said kerogen is output as said product oil and forwarded to the first heat exchanger, and said oil shale and solvent exit in a second output;    a multi-stage solvent extraction unit operated at said elevated temperatures and pressures that receives said second output from the oil separator and removes said solvent from said oil shale;    a second heat exchanger connected to receive said solvent from the multi-stage solvent extraction unit and to remove its heat and apply that heat to an incoming solvent flow applied to a last stage of the multi-stage solvent extraction unit, wherein said elevated temperature is reduced; and    a solvent-residue recovery unit wherein said elevated pressure is reduced in a flow of oil shale received from the multi-stage solvent extraction unit and that flashes said solvents into vapors that are drawn off and recycled to the water removing stage;    wherein, a final solvent recovery from aqueous leach system is accomplished with a staged pressure-relief let-down to atmospheric from about 500-PSIG; and    wherein, a pipelineable synthetic crude oil is derived from said product oil.    
     
     
         2 . The oil-shale processing plant of  claim 1 , further comprising: 
 a distillation column that receives said product oil from the first heat exchanger and that outputs said pipelineable synthetic crude oil.    
     
     
         3 . The oil-shale processing plant of  claim 2 , wherein: 
 the distillation column further outputs a mid-distillate recycle flow that is converted to at least one of tetralin and decalin for an H-donor addition to said solvent.    
     
     
         4 . The oil-shale processing plant of  claim 2 , wherein: 
 the distillation column further outputs light ends in a recycle solvent flow, and a mid-distillate recycle flow that is converted to at least one of an H-donor tetralin and decalin, and wherein said solvent comprises both said light ends and at least one of an H-donor tetralin and decalin.    
     
     
         5 . An improved method for extracting oil products from oil shale, comprising said steps of: 
 crushing a mined oil shale ore into a pulverized oil shale feed;    mixing said pulverized oil shale feed with a hot organic solvent recycled from a distillation column to form a slurry, wherein said solvent is hot enough to strip water from said slurry;    transferring said slurry for kerogen conversion under supercritical conditions for said organic solvent with an H-donor distillate such that said kerogen is converted into a stable, pipelineable crude oil;    transferring said slurry to recycle solvent extraction stage at a supercritical conditions of temperature and pressure for further reaction, and producing an oil product and a separated solid phase;    filtering at less than supercritical conditions said oil product for distillation of a recycle solvent and a mid-distillate fraction, with said oil product being sent to storage;    hydro-treating a mid-distillate fraction recycled from said distillation to provide an H-donor for kerogen conversion;    withdrawing a spent shale after solvent extraction and desolventizing oil shale solids at less than supercritical conditions, wherein a solvent is flashed off with a water to be recycled to a water removal means; and    providing hydrogen, fuel gas and electric power from any gas products of conversion of said kerogen and from a distillation of said solvents.    
     
     
         6 . The process of  claim 5 , wherein: 
 the steps are such that a low-boiling-point-solvent supercritical temperature-and-pressure of about 400° C. and 500+PSIG is used;    the steps are such that said oil shale ore is crushed to about ⅜inch;    the steps are such that said residence time in said supercritical high pressure/temperature to maintain moisture as liquid region is in a region of five to thirty minutes; and    the steps are such that an H-donor mid-distillate recycle with a boiling point of approximately 200° C. is about twenty percent of a low-boiling-point solvent recycle.    
     
     
         7 . The process of  claim 5 , wherein: 
 the steps are such that a hydrogen make-up to hydro-treat a mid-distillate recycle is derived from gases produced in said process.    
     
     
         8 . The process of  claim 5 , wherein: 
 the steps are such that pressure vessels are used for kerogen conversion, oil separation, and solvent extraction.    
     
     
         9 . The process of  claim 6 , wherein: 
 if there is to be no mineral recovery, the steps are such that a spent shale is cooled for disposal via a rotary drum internally sprayed with water;    
     
     
         10 . The process of  claim 6 , wherein: 
 the steps are such that a pressure vessel is used to float any solvent from the residue by an aqueous means, and any wet residue is pressure filtered for recovery of leach-liquor mineral values.    
     
     
         11 . The process of  claim 6 , wherein: 
 the steps are such that a pressure vessel is used to float a mixture of oil, mid distillate, lightened end solvent with an aqueous means, and any wet residue is pressure filtered for recovery of leach-liquor mineral values.    
     
     
         12 . The process of  claim 8 , wherein: 
 the steps are such that said pressure vessels used include an autoclave with a draft-tube venturi.    
     
     
         13 . A process for extracting kerogen and other minerals including alumina and soda ash from mined and crushed oil shales: 
 subjecting a slurry of oil shales to super critical conditions of pressure and temperature to extract any organic carbon content as oil;    extracting organic carbon from said slurry of oil shales which leaves a residue of oil shales;    leaching said resulting residue of oil shales with an aqueous sodium carbonate solution to create a leach liquor that includes alumina and soda ash values;    washing and returning said residue of oil shales after the steps of extracting and leaching to a mine for use as backfill;    precipitating any soda ash values from said leach liquor at around 100° C.;    recycling any alumina values from said leach liquor to the step of extracting;    drying said soda ash values to remove waters of hydration to yield a commercial soda ash product; and    converting any aluminum hydrate a basic aluminum sulphate (BAS) at around 200° C. and under pressure, wherein said BAS is calcined at around 850° C into alumina and any of sulphur oxide gases are recycled after being converted to sulphuric acid.    
     
     
         14 . The process of  claim 13 , wherein: 
 the step of subjecting includes crushing said oil shales for a particle size of about ⅛inch to ¼inch diameter.    
     
     
         15 . The process of  claim 13 , wherein: 
 the step of subjecting includes a solvent with a low boiling point in the range of 100° C. to 140° C.    
     
     
         16 . The process of  claim 13 , further comprising the step of: 
 recycling a hydrogen donor mid-distillate equivalent to tetralin from a cut of said oil.    
     
     
         17 . The process of  claim 13 , wherein: 
 the step of subjecting includes maintaining a temperature of 370-420° C. with an overall residence time of 15-60 minutes.    
     
     
         18 . The process of  claim 13 , wherein: 
 the step of leaching includes an aqueous recycle of sodium carbonate at a temperature of greater than 150° C. and at a pressure of around 200 PSIG.    
     
     
         19 . The process of  claim 13 , further comprising the step of: 
 evaporative crystallization of any sodium carbonate monohydrate leached into a recycled aqueous sodium carbonate leach liquor from said residue after oil extraction, and including temperatures above 100° C.    
     
     
         20 . The process of  claim 13 , further comprising the step of: 
 sparging with CO 2  to precipitate aluminum trihydrate crystals from said leach liquor after any removal of sodium carbonate.    
     
     
         21 . The process of  claim 19 , further comprising the step of: 
 producing a dense soda ash by drying said sodium carbonate monohydrate.    
     
     
         22 . The process of  claim 18 , further comprising the step of: 
 washing, drying, and calcining said aluminum trihydrate crystals into alumina at temperatures of 850-950° C.    
     
     
         23 . The process of  claim 13 , further comprising the step of: 
 recycling a fine aluminum trihydrate for improved production of crystalline aluminum trihydrate from said leach liquor.    
     
     
         24 . The process of  claim 13 , further comprising the step of: 
 precipitating aluminum trihydrate, after the step of precipitating any soda ash values, by seeding with a fine aluminum trihydrate at a ratio of around 1:4, a temperature around 65° C., keeping a concentration of alumina of about 160 grams-per-liter, and a ratio of alumina to sodium carbonate of about 0.7.    
     
     
         25 . The process of  claim 24 , further comprising the step of: 
 agglomerating any precipitated aluminum trihydrate into larger crystals using starch and over a residence time of about 20-25 hours.    
     
     
         26 . The process of  claim 13 , further comprising the step of: 
 directly converting any aluminum trihydrate to basic aluminum sulfate (BAS) using calciner off-gasses in a recycle acid stream, and at a temperature of around 200° C. and under pressure sufficient to keep the constituents in their liquid phases.    
     
     
         27 . The process of  claim 13 , further comprising the step of: 
 purging a recycle of said leach liquor after a depletion of soda ash and alumina values to remove an accumulation of impurities in an aqueous leach circuit.    
     
     
         28 . The process of  claim 13 , after the step of washing and returning, further comprising the step of: 
 crushing and calcining said residue with limestone to produce a material equivalent to a Portland cement.