US3887453A - Process for obtaining oil, gas and byproducts from pyrobituminous shale or other solid materials impregnated with hydrocarbons - Google Patents

Abstract

An ''''Improved process for obtaining oil, gas and byproducts from pyrobituminous shale or other solid materials impregnated with hydrocarbons'''' under such conditions that a mist is permitted to form at the output of the reactor, resulting from the extraction of recycling gases passing in countercurrent with the downwardly moving shale. The improvement results in lower costs, higher amounts of extracted material, higher rentability and, accordingly, better economy.

Description

United States Patent Ueta et al. June 3, 1975 [54] PROCESS F OBTAINING 01 GAS AN!) 3,384,569 5/1968 Peetm 208/11 BYPRODUCTS FROM PYROBITUMINOUS g-ggg'ggg i333 giggl g; SHALE OR OTHER SOLID MATERIALS 3'526586 9/1970 Saxton "III 11:11:: 208/11 IMPREGNATED WITH HYDROCARBONS 3,551,322 12/1970 Clampitt 208/11 75 Inventors: Seiki Ueta Curitiba Parana. 0 3,619,405 11/1971 Smith 208/11 Chaves Ivo, Sao Mateus do Sul, Parana both of Brazil Primary ExaminerC. Davis [73] Assignee: Petroleo Brasileiro S.A. -Petrobras, f y Agent, g fi ROIhWell, M1011,

Rio de Janeiro, Brazil fl & Macpeak [22] Filed: Sept. 1, 1972 pp 285,692 57 ABSTRACT An Improved process for obtaining oil, gas and by- [30] Foreign Ap lication Priority D ta products from pyrobituminous shale or other solid ma- Sept. 6, 1971 Brazil 05357 terials impregnated with hydrocarbons" under such conditions that a mist is permitted to form at the out- [52 us. (:1. 208/11 put of the reactor, resulting from the extraction of w 511 tin. c1 c101 53/06 cycling gases passing in coummwem with the down 581 Fleld of Search 208/11 wardly moving Shaw The improvement results in lower costs, higher amounts of extracted material, [56] References cued higher rentability and, accordingly, better economy.

UNITED STATES PATENTS 3,228,869 1/1966 Irish 208/11 8 Claims, 4 Drawing Figures see-M53 SHEET 3 2?) FIG. 3

SHEET 4 TYPICAL PROFILE OF TEMPERATURE IN BED OF SHALE RETORT Test [OZ-A 500- Tush I02 Tosh I0! Haightof bed, 111

1 PROCESS FOR OBTAINING OIL, GAS AND BYPRODUCTS FROM PYROBITUMINOUS SHALE OR OTHER SOLID MATERIALS IMPREGNATED WITH HYDROCARBONS This invention relates to an improved process for producing mineral oil and other derivatives in distillation retorts from solid materials impregnated with hy drocarbons, particularly pyrobituminous shale and, more generally to the shales.

An object of this invention is to provide the operating system with means for substantially increasing the extraction of mineral oil and other derivatives from shale. A technique is employed such that a mist is formed by the carrier recycling gases for carrying with it the largest possible amount of extracted material.

A further object of this invention is to make the process cheaper, due to the specific carrier recycling gas conditions which increase the output.

The system consists of a vertical cylindrical retort, with tapered ends through the upper end of which the shale is fed in pieces for downward flow thereof in moving countercurrent with the heated gases. Thereafter the shale is discharged through the bottom of reactor. The recycling gases, heated outside the retort, are introduced through the bottom of the reactor, moving in countercurrent with the descending shale, and leave the retort by a side pipe at the top thereof in the form of a mist saturated with extracted material and carrying the partially condensed pyrolysis products For many years research has been carried out to improve the methods and techniques of obtaining the most suitable system for a certain type of shale. The dif ferent systems vary in the basic operation, modes of heating, heating mediums, heat sources, positions of the heat sources, shale aggregation state, frequency of operation, direction of heating, moving of shale in pyrolysis and, finally, the pyrolysis gas dilution. Each of these variation conditions gives rise to other such deviations, which may be combined in a plurality of systems defining the type employed.

The system we want to claim may be defined as regards the above variants, as follows:

basic operation modes of heating heat carrier heat sources direct pyrolysis direct derived from the shale llll The importance of the process of pyrolysis according to the present invention resides in that it is unneces' sary, and indeed prejudicial, to use water for cooling the discharged shale, after extraction, in the bottom of the retort.

Another important point is that the recycling gases coming from the retort in the form of a mist pass through a filtration, separation and condensation system before being heated. Equally important is the introduction of recycling the extraction gases at such a temperature and rate that a mist is permitted to form, this being important for the good performance of the process. The recycled extraction gas will pass through the bed in upwardly, in countcrcurrent with the shale, at a rate not less than 0.2 to 2.0 meters per second. The mist formed should leave with 5% minimum and 25% maximum of condensed material with respect to the pyrolysis products, and at a temperature ranging from 121C to 177C.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which:

FIG. I shows diagrammatically a system according to the invention;

FIG. 2 shows one embodiment of the hopper and rotating valve 3 arrangement of FIG. 1;

FIG. 3 shows a second embodiment of the hopper and valve (3) arrangement of FIG. 1; and

FIG. 4 is a graph showing various retort bed temperature profiles.

The process consists of a system in which the shale, which is mined in pieces of usually not less than a minimum 3.6mm (Vs in) to 200mm (8 inches) and, if desired, mixed with briquettes made of fines produced in the crushing, is carried to a retort by a conveyor belt 1 or other suitable elevator means; from there it passes into a hopper 2 and then through a rotary valve 3 dynamically sealed by an inert gas; next it is passed to an elongated vertical vessel, preferably of circular section, provided with a device for controlling the solids level alarm which controls the speed of conveyor belt 1. This device employs gamma rays or other suitable means. There are two alternatives: first, the use of two valves in series, the sealing gas entering their interconnecting conduit (FIG. 2); second, the use of two parallel mills operating alternately, this reducing or eliminating the need of sealing gas (FIG. 3). The retort consists of a vertical cylindrical vessel whose wall is provided with an internal lining of refractory material 7 covered by a protective metallic coating and an outer layer of thermal insulating material. In its downward vertical movement the shale passes in succession through preheating, drying and retort zones located in the space between the top of the bed and the hot gas distributors 8 where due to the high temperatures, successively its moisture and volatile products, usually gaseous and liquids are liberated. The gaseous fraction, consisting of inorganic and organic gases in variable ratios depending on the nature of the material and the retort conditions, normally contains hydrocarbons, hydrogen and hydrogen sulphide gas as main constituents. The liquid fraction consists of the moisture set free in drying and retorting, and of oil, this latter being of complex composition and hereinafter to be called "shale oil. A non-volatile organic residue, hereinafter referred to as coke will remain in the solids. The solids and coke, from now on referred to as exhaust shale, pass through the cooling zone 9 located between the hot gas distributors 8 and a discharge mechanism comprising deflectors 10, fixed retarding plates 11 and a speed controlled movable grid 12 which makes a translational movement around the retort axis. In this mechanism-especially developed for providing a continuous uniform flow of the mined shale subject to the action of gravity in large diameter cylindrical vessels the shale rests on the deflector assembly l0 and retarding or resting plates 11 in virtue of its angle of repose, there being no flow when the movable grid 12 is at the rest (the whole discharge or outlet system is described in Brazilian Pat. No. 69.423 granted on Apr. 29, 1964). in this way the flow, the temperature and, accordingly, the mist formation are controlled, this being the basic condition for optimizing the system operation. By moving the movable grid 12, the shale is forced to move horizontally and alternately towards the internal and external circumferences of retarding plates 11, from where it freely falls into a hop per 13 which forms the conical retort bottom passing through a cold gas distributor 14. From the hopper 13 in the retort bottom the retorted shale is passed through a speed controlled rotary valve 15 by the level controller to a tank 16 that has the double function of providing hydraulic sealing for said rotary valve and means for making a sludge of the retorted shale and water. the sludge being pumped to the retorted shale disposal location by a centrifugal or piston type pump 17. There are two alternatives: first, the rotary valve is also dynamically sealed by inert gas, then dispensing with the water seal; second, two series connected valves are used, the sealing gas entering the interconnecting conduit.

Cold gas is admitted to the retort through the gas distributor 14, consisting of several horizontal tubes paral lelly disposed with respect to each other and provided of two rows of holes spaced at about 90 to each other; each rows of holes delivers several gas jets downwardly at an angle of about 45 to the vertical, thus providing homogeneous distribution of gas in the whole reactor bottom section and preventing entrance of shale into the holes and the actual distributor pipes. The cold gas gage pressure at the retort input is 0.3 to 1.5 atmospheres, which is sufficient to overcome the combined resistence of the bed of solids, the circulation conduits and devices, while still maintaining the whole system at a pressure slightly above atmospheric, this preventing leakage of air into the apparatus, and its temperature is superior to the room temperature although substantially less than the destructive distillation temperature named in this specification retorting temperature," which is usually about lOOC. The cold gas admitted to the bottom of retort, as described, flows upwardly in countercurrent with the exhaust shale that is falling freely and passing through the free spaces of the dis charge or outlet mechanism and the exhaust shale bed; said free spaces of the discharge mechanism are appropriately formed to assist in the homogeneous distribution of gas flow in the whole retort section.

In its upward path the cold gas exchanges sensible heat with the hot descending solid the exhaust shale that gives up the major part of its heat and leaves the retort at a temperature substantially lesser than the retorting temperature, i.e., at the cold exhaust shale temperature, usually of from 200C to 300C. The cold gas reaching the retorting zone at a temperature similar to but less than the retorting temperature is mixed with the hot gas admitted through the respective distributor. This hot gas distributor 8, formed similarly to the cold gas distributor 14, consists ofa metal suitable for resisting high temperatures and is provided with deflectors coupled to the tubes positioned above them. Said deflectors are designed to protect the pipes from the abrasion caused by the solids and deviate the flow of solids to the free spaces existing between the distributor tubes and between the tubes and the internal wall of retort. The gas entering the retort through the hot gas distribu tor 8 enters at a temperature above the retorting temperature and under a pressure slightly less than the inlet pressure of the cold gas, these pressures differing as a function of the mechanical resistence to which the gas is subjected in its upward path; said hot gas inlet temperature usually ranges from 400C to 800C. From the level of the hot gas distributor 8 to the top, the gas passing through the exhaust shale refrigerating zone 9 is mixed with the hot gas, the ratio of hot gas to cold gas being regulated in such a way that the resulting temperature is the retorting temperature; the resulting amount of gas is regulated so that during its upward flow it gives off sufficient sensible heat to effect successively and from the bottom to the top, the retorting, heating and drying of the shale. The shale is at the same time heated in the retorting zone and sets free generally gaseous or normally liquid compounds, of organic and inorganic nature, which are produced by thermal decomposition of the organic matter spread through the mineral mass, and by the thermal decomposition of some inorganic compounds also present. Among the main compounds usually contained in the retorted product are hydrogen sulphide gas, carbon dioxide, hydrogen, saturated and normally gaseous insaturated aliphatic hydrocarbons, and organic compounds normally liquids called shale oil that consist of aliphatic saturated and insaturated, naphtenic and aromatic hydrocarbons and of heterocyclic organic compounds containing oxigen, nitrogen or sulfur, and of the water formed in the thermal decomposition of the organic and inorganic compounds. In the drying zone the gases give up sensible and latent heat in order simultaneously to heat the solids, evaporate moisture from the shale and to cool themselves to a temperature ranging from [00C to 150C, at which most of the normally liquid fractions are condensed to a fine heavy oil mist from the shale that is drawn by the mixture of heat carrier gases with the gases produced by retorting. Leaving the bed of solids, the gases and mist of heavy shale oil pass into a chamber 6, solid free, where its ascending speed is from 0.5 to 2.0 meters per second, and where only a dust of shale and the mist of oil are drawn. From the chamber 6 the gases are led through the vertical collecting tubes 18 positioned at the top pf the retort in such a way as to maintain an homogeneous upward gas speed to one or more convergent conduit systems 19, of increasing sectional areas, designed in such a way that the speed of the gases entering the collecting tubes 18 remains approximately constant; the large cross section end segments are connected through tubes 19 with the inlet of one or more centrifugal separators, preferably cyclones 20 in series with electrostatic precipitators 22, through tube 21 where the gases are freed of mist and dust. Such separators are designed to retain in the coarser particles of solids and oil in the cyclone 20 and the finer particles in the electrostatic precipitators 22. The system efficiency is from to 99.9%.

The cyclones 20 have inlets 23 for the shale oil in order to facilitate the continuous or intermittent washing of its walls, in order to avoid deposition of dust and heavy oil; and from there the liquid and solid materials leave through tubes 24 to a separating apparatus 25 from which the liquid is passed through tubes 26 and 32 to settlers 33 and the solids to the waste, through conduits 27 and 35; the liquid may contain some condensed water, as a consequence of the slight cooling due to the heat loss of the gases through the walls of the apparatus. In the electrostatic precipitators 22, which may also be oil washed admitted through the tubes 28, as in the case of cyclones, the finer particles are separated from the oil, dust and condensed liquids; all the solid and liquid materials are drained through the tubes 29 and separating apparatus 30 ensures that the liquids 6 are passed through the tubes 31 and 32 to the settlers e 33 and the solids to the waste, through the tubes 34 and 15; 9012, 35. The OII fractions separated in the settlers 33 are G asflossgs f 2.41 2.09 ar on( ry asis). d I113 985 passed through the tubes 36 pump 37 and tubes 38 to Hydrogen (dry basis) q 2) L56 storage, and the water fractions, through the tubes 39, 5 Sulfur (dry basis). /r 3.90 3.9: i Ignition loss, 7r 22.30 I774 tgytgfog'uasltse) or for recovery of dissolved compounds High Heating Vahe mug I537 I119 The gases, leaving the precipitators 22, pass through tubes 40 to a compressor 41, where they are Compressed under sufficient pressure to overcome the sys- TABLE II tern reststence cause by the plpmg, valves, shale bed, separators and heaters, and are split in two portions, PROPERTIES OF SHALE 0 one being sent through tubes 42 to a cooler 43 and the 4 other through pipes 44, the latter, in turn, being split in It g p g elementary analysis r two portions. one through pipe 45 to a heater 46 where ig g it is indirectly heated by the combustion gases of shale Nitrogen 0.52% gas 62, shale oil 63, or other available fluid fuel; the gig; heated gases leave the heater through pipe 47 and are 2. Typical physical properties introduced into the retort through the hot gas distribu- 5 gx g b m 8-2 tor 8. The other portion of the recycling gas is passed Asphaltgnes and resins Weigh, through pipe 48 to the retort and admitted to it through 2 b s t 0.028

. n1 me point 30.0 the cold gas dlstrtbutor 14. The combustion gases leave Pour point. 0 the gas heater through stack 49 and are delivered to the Viscosity at 5 0C. est 7 20.76 atmosphere without contact nor mixture with the recy characlerlzulmr UOP K cling gas.

The gas admitted to the bottom section of cooler 43 is cooled by direct contact in countercurrent with a TABLE I" water spray 61 or cold light oil spray that falls from the top of the vessel and leaves through pipe 50 for further r g treatment. The condensed products in the cooler are LRTIES OF SHALE drained along with water or oil admitted in the top via Components Volume '12 pipe 51 to the settler 52 where the light oil and water H2O 1.28 are separated. The 01] is passed to storage through the 15 pipe 53 while the water is passed through the pipe 54 (:rHm 1.41 to pump 55 and thereafter to the waste or treatment, through pipes 56 and 57 and to recycle in the cooler I3 43, through pipe 58, exchanger 59 and pipe 60. 5 Studies made on mined shale provided the results d 5,, found in the following tables and FIG. 4, Table I shows H28 25.8l the result of laboratory tests of two average Samples, 3%? RSH representing the feed used in the retorting operation; in C0 L67 Table II and III are the results of laboratory tests of oil 8 and gas obtained in several tests of the retorting opera- 5 tions; Table IV shows the tests of exhaust shale produced in various retorting operations; and Table V is an abstract of operational conditions of some retorting op erations and respective yields. FIG. 4 represents typical r b d TABLE IV temperature profiles in the retort e TABLE I PROPERTIES OF EXHAUST SHALE LABORATORY TESTS OF TWO AVERAGE SAMPLES or SHALE PROPERTIES L FEED Carbon, '7( 7.74 5.63 PROPERTIES TESHIHNR. TESI'IO7WR. y g q 08' 0-60 7 55 Sulfur, 7 273 30-4 lgnitlon loss 7r I523 I053 Moisture, 72 3.59 3.25 r j Fischer Test y basis) (72 Superior calorific power, cal/g 710 6-! TABLE V OPERATING CONDITIONS IN PILOT RETORT TEST NR. TEST NR. TEST NR. TEST NR. 101 l03-A lO4-A 27 Flow of solids, k h m* I621 1003 2230 2497 Flow of g glthhml 1442 1506 2199 2032 Average diameter of solids, mm 13.39 18.80 17.98 16.3 Maximum temperature of bed, C 434 539 418 472 Temperature of hot gases, C 552 634 48] 557 Temperature of residue, "C 259 258 21 1 I74 Outlet temperature of products,C l26 141 I48 I28 Oil recovering, weight 89.5 [00.8 100.3 I042 We claim:

1. A non-combustion process for obtaining mineral oil and other derivatives from pyrobituminous shale or other solid materials impregnated with hydrocarbons, the said process being non-combustive and carried out in a vertical distillation retort, wherein the mined shale or other solid materials is continuously fed at the top of said retort through an inert gas sealed valve, wherefrom said mined shale or other solid materials are evenly distributed to the retorting zone and then descend to a cooling zone below the retorting zone. the retorting being carried out at super-atmospheric pressure by a mixture of substantially oxygen-free recycling gases previously and indirectly heated outside the retort. said heated recycling gases being introduced into the bottom of the retorting zone of said retort at a higher temperature than the retorting temperature, and of substantially oxygen-free recycling gases introduced cold at the bottom of said retort into the cooling zone which in upwardly flow through the cooling zone exchange sensible heat with said retorted shale or other solid materials that is continuously withdrawn from the bottom of said retort through an inert gas sealed valve. the liquid and gaseous retorting products being drawn from top of said retort.

2. The process according to claim 1 wherein the gases produced in the retorting process are separated from liquid components and from solid material in suspension by means of a system of cyclones and electrostatic precipitators in series, and then part of said gases is heated prior to its injection into the bottom of said retorting zone. I

3. The process according to claim 1 wherein said heated part of substantially oxygen-free recycllng gases is indirectly heated in a furnace outside the retort to a temperature between 9fl0--l30(lF.

4. The process according to claim I wherein said part of substantially oxygen-free recycling gases without previous heating or cooling is introduced into the bottom of said retort at a temperature of about 212 F as so-called cold gases.

5. The process according to claim 1 wherein the optimum temperature of retorting is between 800 l,O0OF.

6. The process according to claim 1 wherein the retorting is accomplished in the retort at an internal pressure between 7.1 and 2l.3 psig.

7. The process according to claim 1 wherein the size of the pieces of said mined shale fed to said retort l5 between 5.3 and 200 millimeters (0.25 and 8.00 inches).

8. The process according to claim 1 wherein the mixture of recycling gases and the liquid and gaseousfreltorting products leaves the top of said retort in the o lowing conditions:

a. velocity of 0.2 to 2.0 meters per second;

b. temperature between 25035GF; and d c. 5 to 25% condensate referred to the liquids an gaseous retorting products. A

Claims (8)

1. A NON-COMBUSTION PROCESS FOR OBTAINING MINERAL OIL AND OTHER DERIVATIVES FROM PYROBITUMINOUS SHALE OR OTHER SOLID MATERIALS IMPREGNATED WITH HYDROCARBONS, THE SAID PROCESS BEING NON-COMBUSTIVE AND CARRIED OUT IN A VERTICAL DISTILLATION RETORT, WHEREIN THE MINED SHALE OR OTHER SOLID MATERIALS IS CONTINOUSLY FED AT THE TOP OF SAID RETORT THROUGH AN INERT GAS SEALED VALVE, WHEREFROM SAID MINED SHALE OR OTHER SOLID MATERIALS ARE EVENLY DISTRIBUTED TO THE RETORTING ZONE AND THEN DESCENT TO A COOLING ZONE BELOW THE RETORTING ZONE, THE RETORTING BEING CARRIED OUT AT SUPER-ATMOSPHERIC PRESSURE BY A MIXTURE OF SUBSTANTIALLY OXYGEN-FREE RECYCLING GASES PREVIOUSLY AND INDIRECTLY HEATED OUTSIDE THE RETORT, SAID HEATED RECYCLING GASES BEING INTRODUCED INTO THE BOTTOM OF SAID RETORTING ZONE OF SAID RETORT AT A HIGHER TEMPERATURE THAN THE RETORTING TEMPERATURE, AND OF SUBSTANTIALLY OXYGEN-FREE RECYCLING GASES INTRODUCED COLD AT THE BOTTOM OF SAID RETORT INTO THE COOLING ZONE WHICH IN UPWARDLY FLOW THROUGH THE COOLING ZONE EXCHANGE SENSIBLE HEAT WITH SAID RETORT SHALE OR OTHER SOLID MATERIALS THAT IS CONTINUOUSLY WITHDRAWN FROM THE BOTTOM OF SAID RETORT THROUGH AN INERT GAS SEALED VALVE, THE LIQUID AND GASEOUS, RETORTING PRODUCTS BEING WITHDRAWN FROM TOP OF SAID RETORT.

1. A non-combustion process for obtaining mineral oil and other derivatives from pyrobituminous shale or other solid materials impregnated with hydrocarbons, the said process being non-combustive and carried out in a vertical distillation retort, wherein the mined shale or other solid materials is continuously fed at the top of said retort through an inert gas sealed valve, wherefrom said mined shale or other solid materials are evenly distributed to the retorting zone and then descend to a cooling zone below the retorting zone, the retorting being carried out at super-atmospheric pressure by a mixture of substantially oxygen-free recycling gases previously and indirectly heated outside the retort, said heated recycling gases being introduced into the bottom of the retorting zone of said retort at a higher temperature than the retorting temperature, and of substantially oxygen-free recycling gases introduced cold at the bottom of said retort into the cooling zone which in upwardly flow through the cooling zone exchange sensible heat with said retorted shale or other solid materials that is continuously withdrawn from the bottom of said retort through an inert gas sealed valve, the liquid and gaseous retorting products being drawn from top of said retort.

2. The process according to claim 1 wherein the gases produced in the retorting process are separated from liquid components and from solid material in suspension by means of a system of cyclones and electrostatic precipitators in series, and then part of said gases is heated prior to its injection into the bottom of said retorting zone.

3. The process according to claim 1 wherein said heated part of substantially oxygen-free recycling gases is indirectly heated in a furnace outside the retort to a temperature between 900*-1300*F.

4. The process according to claim 1 wherein said part of substantially oxygen-free recycling gases without previous heating or cooling is introduced into the bottom of said retort at a temperature of about 212*F as so-called cold gases.

5. The process according to claim 1 wherein the optimum temperature of retorting is between 800* - 1,000*F.

6. The process according to claim 1 wherein the retorting is accomplished in the retort at an internal pressure between 7.1 and 21.3 psig.

7. The process according to claim 1 wherein the size of the pieces of said mined shale fed to said retort is between 5.3 and 200 millimeters (0.25 and 8.00 inches).

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