US1838622A - Method of and apparatus for retorting carbonaceous material - Google Patents

Description

Dec. 29, 1931.

METHOD 0F .AND APARATUS FOR RTORTING CARBONAGEOUS MATERIAL H. N. HERICK -1,8f38,622

Filed April 30. 1925 I l5 Y ./5

heat thereto.

Patented Dec. 29, 1931 UNITED STATES P ATNT oFFicE' HENRY N. HERRICK, OF BERKLEY, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO STANDARD OIL COMPANY OF- CALIFORNIA, 0F SAN FRANCISCO, CALIFORNIA, A

CORPORATION OF DELAWARE METHOD OF A ND APPARATUS FOR RETORTING CARBONACEOUS MATERIAL Application filed April 30, 1925. Serial No. 26,869.l

This invention relates to the extraction of the volatile constituents of shale, coal, lignite, tarry sands and similar carbonaceous or bituminous material by the application ofv It also relates to the production of a valuable solid fuel from materials that are sufficiently rich in carbon.

In retortin-g methods heretofore practiced on materials of the character mentioned i0 above, it has been the custom either to heat the exterior walls of the retort containing the lmaterial so that the reaction 'temperature within the material itself is obtained by conduction of heat through the walls of the retort, or to heat the material by burning some of it within the retort in the presence of the material being treated, the solid or fixed carbon content of the material remaining after extraction therefrom of the volatile constituo ents.

In .the first method mentioned,I asheretofore practiced, the products of combustion of the fuel used for heating the materials have been kept separate and out of direct contact with the materials being retorted, and, therefore,l it is diicult to'obtain an economical transfer of heat.

According to the second method, as heretofore practiced, the hot gases resulting'from 3 the combustion pass in direct contact with the material being retorted. The apparatus employed in performing this second method is commonly referred to as the internally fired retort type, and by this second method there is obtained a more economic and more highly efficient transfer of heat than is the case where the retort is externally heated. However, in

this prior internallyred'retorting method,

it is necessary either that all of the solid carbon content of the material be burned as fuel for obtaining certain products, or that the portion of the solid carbon content, necessary to be'burned as fuel for obtaining the distillation temperatures, be burned in the presence of the remaining solid carbon content, so that there results either a partial combustion of the entire solid carbon content, or a containination of the unburned solid carbon content with the ashes and other residue resulting 5,0 from the burned portion of the solid carbonvcontent. In either event, it is practically impossible to obtainY by the second method any of the solid carbon content as a clean fuel,

By the practice of this invention there is obtained the efficient and economical heat transfer that attends .the prior known method performed in the internally fired type of rei tort, while there is no contamination of the solid carbon content, remaining after extraction of the volatile constituents, with the ash and other residue resulting from the burning of such portion of the-solid carbon content as is burned for fuel in performing the method.

In this new method there is employed a continuous operation in which that portion of the solid carbon content used as' fuel is burned out of contact with the remaining solid carbon content, and I am enabled to effect accurate control of conditions so as to obtain the most efficient heating and .relatively great capacity of throughput.

The accompanying drawings illustrate an apparatus constructed in accordance with the provisions of this invention and capable of performing the new method, Fig. .1 being more or less diagrammatic and largely in vertical midsection, and Fig. 2 being a fragmental sectional elevation on the line indicated by 2-2, Fig. 1.

Referring to the drawings, the apparatus has a vertical chamber lv in which is formed a column of the carbonaceous material to be treated and through which the materials pass and to which they are continuously fed at the top. The chamber comprises a section or zone A at its upper end of relatively small cross-sectional area surrounded by apassage Located externally of the vertical chamber at an elevation and adjacent tothe base of the retorting zone B is a furnace or combustion zone 3. Leading from the top of the furnace 3 is a iue passageway 4 which connects through an annular passage 5 with a vertical flue 6, the passageway 5 surrounding the upper portion of the zone C. Leading inwardly from the annular passage 5 is a radial opening or openings 7 which admit the passage of hot gases from the furnace 3 into the lower end of the zone B. From this it will be seen that a portion of the hot gases from the furnace 3 will be conducted to the column of material at a level above the lower end of the column and pass in direct contact with the material undergoing treatment, which material is indicated in the drawings as filling the apparatus. It will also be seen that another portion of the hot gases from the furnace will pass -through the flue 6 and,

since the said flue connects with the passage 2, said hot gases will pass into said passage 2, thus to preheat the materials passing down through the zone A.

Positioned above the top of the vertical chamber 1 is a feed hopper 8 provided with a partition 9 which separates the hopper into two compartments 10. These compartments are provided at the top with suitable doors 11 normally kept closed by any suitable means. In this instance the doors 11 are suspended by chains 12 from levers 13 which are fulcrumed at 14 on standards 15 supported on top of the hopper. On the levers 13 are counterweights 16 sullicienty heavy to normally hold the doors 11 closed against the under face of the hopper top. Each hopper compartment has at its lower end an opening 17 communicating with the chamber 1, and the discharge of the materials through the openings 17 may be regulated by a suitable valve 18. The valve 18 may be moved into positoin to close either opening 17, thus to permit material to be fed to the vertical chamber from one of the compartr ments 10 while the other hopper compartment is receiving fresh material. The valve 18 may be operated by any suitable means and, in this instance, is mounted on one end of a vertical shaft 19 extending up through the partition 9 and rovided at its upper end with an operating nob or handle 20. By. turning the knob 20, the valve 18 is swung across either opening as desired.

The flue gases discharge from the passage 2 through an exhaust pipe 21 which is provided with an exhaust blower 22. The exhaust pipe 21 is controlled by a damper 23. By operating the blower 22 atv different speeds and by closing and opening the damper 23, perfect control of the volume of gases for preheating the materials is' obtained.

From the lower portion of the preheating zone A the material passes downward intothe upper portion of the zone B, thence continuously downward therethrough, and during this time said materials come in direct contact with the main portion of the hot gases supplied by the furnace 3. These gases, as heretofore explained, enter the chamber 1 through the radial openings 7 and pass into the base of the retorting section B. The products of distillation from the materials undergoing treatment, i. e., the volatile constituents thereof, together with that portion of the hot furnace gases which is passed in immediate contact with the treated materials, are removed from the reaction zone B through a number of passages 24, 25, 26 which are located at different levels along the zone B. Valves for controlling the passages 24, 25, 26 are indicated at27. The passages 24, 25, 26 connect through a pipe 28 with condensers 29, 30, the pipe 28 being provided with valves 31, 32. vThe condenser 30 connects with a conduit 33 and also through a pipe 34 with an exhaust blower 35.

The condenser 29 is primarily an auxil iary or refiux condenser and may be of any conventional type, either air cooled or water cooled, and is for the purpose of condensing the heavier constituents of the outgoing vapors. Provision is made for returning to the retorting chamber B the heavier constituents obtained as a reflux condensate from the condenser 29 and for this purpose a conduit 36 extends from the condenser 29 and discharges into the zone B. The conduit 36 is provided with a valve 37 for controlling the amount of reflux condensate discharging to the retort or said valve may be closed to divert the reflux condensate along with the residual vapors from the condenser 29 into the main condenser 30, where condensation is completed. The liquid products obtained from the condenser 30 discharge into storage through the conduit 33 and the uncondensed gases will discharge through the exhaust blower 35. The valve 31 may be manipulated for diverting the gases and vapors through either the condenser 29 or condenser 30 or through both, as desired, and thus the valve reaction zone B are pyrometers 38 for accurate temperature control purposes.

From the lower end of the reaction zone B the spent material passes downward into zone Cand the lower portion of zone C is provided witha Stoker 39 constructed and arranged to divert some of the spent material from the column and move it laterally to the furnace 3, in which the carbon content of the diverted portion is burned as fuel out of contact with the column for producing the temperatures necessary in the retorting of the materials. It is to be noted that the gases of combustion are conducted from the furnace to the column of material above the level at which diversion of the material takes place.

The stoker 39 may be of any conventional design and, by the construction disclosed, the spent material is caught within the Stoker and diverted in a direction normal to the vertical axis of the column of material into the furnace 3. The stoker 39, in the present instance, is operated through a lever system 40 actuated by a piston 41 working in a cylinder 42. The spent material diverted into the furnace 3 travels in a relatively thin sheet down over an inclined grate 43 in the combustion chamber of the furnace and is finally discharged automatically through discharge mechanism 44 into a chute portion 45 of the furnace. The ,chute 45 is provided with a door 46 and, when this door is opened. the ash from the spent material discharges into suitable conveying means which, in this instance, is a car 47.

The portion of the spent material not diverted into the furnace 3 passes downwardly into the zone D where it is kept free from contamination of ash and other residue resulting from burningof that portion of the material that is vutilized for production of the hot retorting gases. Thus it will be seen that if coal or any other material capable of use after the volatile constituents have been removed is treated, a clean fuel is obtained in the zone D, and this fuel is continuously discharged through a mechanical grate 48 into suitable conveying means which, in this instance, is a car 49.

Preferably, the zone D is surrounded by a spiral passage 50 which 'connects at its upper end with the upper end of the chute 45, said chute being directly beneath the grate 43 ofthe furnace. A blower 51 connects with the lower end of the passage 5() for supplying air to the furnace and it will be seen that the air thus suppliedV because of passing around the hot materials in the zone D will become preheated to a relatively great degree, thus producing efficient combustion of the materials in the furnace 3. Furthermore, the air, furnished to the furnace, in thus being heated by the clean fuel in the zone D, cools said fuel.

It is sometimes desirable to retort the material in the presence of steam and this may be accomplished, in this instance, by introducing water to the'zone D through a pipe 52 having a valve 53. This water is converted into steam by residual heat contained in the clean fuel in the Zone D, thus effecting further cooling of said fuel. The steam formed from the water admitted to the Zone D passes upward through the mass of material in the zones D, lC successively and into the zone B.

It will be readily understood from the foregoing that, inthe operation of this new method, there is direct contact with the hot gases,`which supply the heat, with the material undergoing treatment. Thus I am able to obtain the advantages which attend an internally fired retorting operation and at the same time I am able to separate that portion of the spent material used for fuel from the remainder of thek spent material. In consequence of this last mentioned feature, when the material being treated is of a nature to make it possible, I am able to obtain a material amount of clean fuel comprising a substantial portion of the spent material which has passed through the retort, together with itssolidcarboncontent. Thisfuel,being free from contamination by the ash and other residue vresulting from the combustion of some of the materials in the furnace, can be removed in a clean state so that it'will be .available for industrial processes in which it is desirable to have a fuell ofthe nature of coke or one that is freefrom volatile gases.

In retorting shale by prior known internally fired methods requiring complete burning of all of the solid carbon content of the spent shale, it frequently happens that more shale is burned as fuel than is necessary to effect the retorting. Consequently, there results an undue dilution of the evolved vapors with the gases of combustion. In other words, more gases of combustion are drawn off with the vapors than-would be the case if only a sufficient amount of shale could be burned to produce the requisite retorting temperatures. The excess gases of combusf `tion interfere with efficient condensation ofk the vapors that are to be recovered, and by my improved method the excess gases do not have access to the column of material since the material employed as fuel is burned out of contact with the column and only al suiiicient volume of the combustion gases is admitted to the column to effect the desired results.

It Will also be understood that, in the handling of the vaporized material evolved from the retorted material, I am enabled to turn any desired amount of refiux condensates to the retorting zone B for redlstillation `or cracking. It will bev noted that, because of the provision of the pyrometers for observing the temperatures in the retortmg zone, the exhaust blower 22 and the damper 23 for lcontrol of the quantity of hot gases used preheating the material, the exhaust blower 35 for drawing the gaseous products through the condensing units, the arrangement for returning the heavy condensate to the retort andthe blower 51 for effecting a forced draft around the hot spent material and thence to the volatile products to the cracking of the heavier ends and the conversion of said heavier ends into lighter fractions.

The fixed or uncondensed gases which may discharge from the exhaust blower may be of such a nature that the may be burned as fuel. In this event, such gases, if desired, may be introduced to the furnace 3. Such gases are preferably introduced at a point above the material on the grate 43. For conducting these gases there is provided a conduit 54 leading from the blower 35 to a burner 55 in the furnace. The conduit 54 is provided with a valve 56.

Also it may be desirable, in some-instances, to divert some of the-products of combustion away from the retort and such products can be used for purposes other than retorting or preheating the materials. This will be better understood if it be considered that, in operating a system such as that outlined in this application, it is of great importance that no excess air be allowed to pass through the fuel bed and into the distilling zone. If any such air is allowed to pass through the fuel bed the oxygen will unite with the carbon in the distilling zone and produce excessive heat and clinkering or it will unite with and destroy the oil vapors. For this reason a deep bed of fuel would be kept on the grates, and this may make it necessary to burn more of the fixed carbon or the spent shale in the furnace than would be necessary merely to produce sufficient heat for the reheating and the retorting o erations. n fact, in order to maintain a tile bed thick enough to prevent free oxygen passing through it, it may be necessary to divert practically all of the s ent shale from the retort to the grates in w ich event the shale retorting process would not give rise to some of the spent shale being taken fromthe system as a. clean fuel. When such a quantity of spent shale is burned as fuel for the above mentioned purpose it will be clear that an excess of heat in the form of high temperature products of combustion' will be available. To carry away the excess gases of combustion, an exhaust blower 5T connects with the upper end of the flue 6 by a pipe 58. Such products of combustion discharged into the pipe 58 may be discharged to the atmosphere or to any suitable point, and the pipe 58 is provided with a valve .59 which regulates the amount of flue gases drawn off.

Though I have shown in the drawing a single furnace to supply the hot gases used for both the retorting and the preheating of the materials, I do not desire to limit the invention to the use of a single furnace for both of these purposes, as it will be evident that independent furnaces can beused to supply the I hot gases for the two purposes.

It will also be evident that a suilicient draft may be obtained through the use of the blower 35 alone without operating the blower 5l, and that the blower 35 need not necessarily be positioned on the cold side of the condenser 30 as it could be located equally well between the retorting chamber and the condenser.

My invention, therefore, is not to be construed as limited to the specific e uipment and arrangement herein described, ut is of the scope covered by the claims.l

I claim:

1. An apparatus of the character described comprising a vertical chamber, a combustion chamber at one side of the vertical chamber, an outlet for said vertical chamber intermediate its height communicating with said combustion chamber and adapted to discharge solid material from said vertical chamber into the combustion chamber, means below the level of said outlet to discharge solid material from the vertical chamber, and an inlet leading into said vertical chamber above said outlet, means to pass aseous products 4of combustion from sai combustion chamber into said vertical chamber through said inlet to vaporize volatile constituents of the material in said vertical chamber, a condenser connected with said vertical chamber at a point substantially above the level at which said inlet communicates with said vertical chamber, a burner in the combustion chamber, and means to pass gases from the condenser to said burner.

2. The method of retorting solid carbonizable material comprising forming a downwardly moving column of the material out of contact with the atmosphere, diverting a portion of the material in process of treatment from the column, carbonizing the material in said column above the level of the diversion by burning the material thus diverted from the column and introducing the gases of combustion into said column at a level above the level atwhich the diversion of said portion of the material takes place to vaporize volatile constituents of the material, taking off the vapors and gases of combustion from the column, conducting air around the column below the level at which said diversion takes place in heat exchange relation with the material in said column but out of contact therewith to cool the material and preheat the air, and conducting the heated air to the burning material.

3. The method of retorting solid carbonizable material comprising forming a down-Q wardly moving column of the material out of contact with the atmosphere, diverting more material in process of treatment from the column than is necessary for furnishing by combustion of the Idivertedmaterial the required amount of heat to vaporize all of the volatizableconstituents of the material remaining in the column` carbonizing the material in said column above the level of the diversion by burning the material thus diverted and introducing a portion ofthe gases of combustion into said column at a level above the vlevel at which the diversion of said portion of the material takes place to A vaporize volatile constituents of the material in the column, drawing off from the zone of combustion the remainder of the combustion gases and passing the same around the upper portion of the column in heat exchange relam tion with but out of contact with the material in the column, at a level substantially above the level at which the introduction of combustion gases into the column takes place. 4. An apparatus of the character described, comprising a vertical chamber, a combustion chamber on one side of the vertical chamber, I means communicating the chambers to afford passage of solid material from the vertical chamber to the combustion chamber, the com- 20 bustion chamber communicating. with the vertical chamber above the level of said means, and means' forming an air passage around the lower end portion of the chamber,

said passage communicating at its yupper end with the combustion chamber.

- Signed at San Francisco, Calif., this 17th day ofApril 1925. HENRY N. HERRICK.

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