US3222261A

US3222261A - Coking process

Info

Publication number: US3222261A
Application number: US250516A
Authority: US
Inventors: Nagelvoort Adrian
Original assignee: Complex Inc
Current assignee: Complex Inc
Priority date: 1963-01-10
Filing date: 1963-01-10
Publication date: 1965-12-07
Anticipated expiration: 1982-12-07

Description

Dec. 7, 1965 A. NAGELVOORT comm rnocmss Filed Jan. 10, 1963 INVENTOR. ADRIAN NAGELVOORT ATTORNEYS States Patent 3,222,261 COKING PROCESS Adrian Nagelvoort, Los Altos, Calif assignor, by direct and mesne assignments, to Complex, Incorporated, Menlo Park, Califi, a corporation of California Filed Jan. 10, 1963, Ser. No. 250,516 Claims. (Cl. 202-17) This invention relates to the preparation of coke and more particularly to an improved system and method of preparing coke from coal.

In the past, coal has been converted to coke by batch processes such as steam distillation. In steam distillation, lump coal is fed into an autoclave where steam under high pressure and high temperature is applied. The volatiles of the coal, together with the steam, are drained ofi gradually. The coke is left within the autoclave long enough to complete the coking process. A process such as this takes from twelve to twenty-four hours. Another batch process requiring comparable time employs ovens with externally applied heat.

It is a general object of the present invention to provide an improved method and means for converting coal to coke.

It is a more particular object of the present invention to provide an improved means and method of quickly converting coal to coke.

It is yet another object of the invention to provide a simplified continuous method and means for converting coal to coke.

These and other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawing, which discloses, by way of example, the principle of the invention and a preferred mode which has been contemplated of applying that principle.

In the single figure of the drawing, there is shown schematically a system for converting coal to coke according to the invention.

Generally, according to the invention, there is provided a method of coking crushed coal which includes the steps of directing a stream of super-heated steam under pressure along an inclined enclosed passage of predetermined extent, introducing coal into the stream at the lower end of the passage so as to release volatiles from the coal and convert the coal to coke for discharge at the elevated end of the passage. The angle of incline of the passage and the pressure of the steam are such as to permit transport of the lightened coke material by the stream along the passage to the substantial exclusion of the unconverted coal, so as to separate the former from the latter. As the coke is discharged from the passage, it is collected.

According to a preferred method, coal such as bituminous coal, is crushed to a size which will pass a ring of the order of 7 inch. The crushed coal is introduced into an enclosed and substantially unobstructed passage inclined at a predetermined angle on the order of five or six degrees. The passage is open at the elevated end so as to discharge material from the passage. superheated steam under pressure is injected into the lower end of the passage so as to convert the coal to coke and transport the latter up the passage.

With reference to the figure, there is provided means forming an elongated enclosure having a substantially unobstructed insulated passage therealong which is inclined at a predetermined angle. Thus, in the drawing, the enclosure structure includes an elongated portion 10 which includes a substantially cylindrically shaped metal liner 11 surrounded by insulation 12 and enclosed by an outer wall 13. The liner 11, therefore, forms a substantially unobstructed passage extending longitudinally of the portion ice 10. Liner 11 is disposed at an angle on the order of five or six degrees to the horizontal by supports 14 and 15, schematically shown.

Means are provided which serve to direct a stream of superheated steam under pressure, into and upwardly along the liner 11. Said means comprises steam line 16, valve 17 and steam line 18, having a pressure relief valve 19 therein. A superheated steam boiler is represented by the chamber 21 including a plurality of turns of the steam line 22 which connects with line 18. A plurality of burners 23 are schematically shown for forming steam in line 22.

Means are provided serving to continuously direct crushed coal into the injected stream of steam at a lower region of the inclined passage. In this manner, volatiles are released from the coal by heat from the steam. The means for delivering the coal can include a conveyor such as endless belt 24 driven to discharge crushed coal into a bottom opening hopper 25, through a one-way valve 26 into liner 11. Valve 26 is of suitable construction whereby coal is permitted to pass into liner 11 without substantial loss in pressure of the applied steam.

The enclosure further includes a trap portion 27 formed as a hopper-like chamber wherein one wall 28 is disposed to form a sill 29 with respect to the discharge opening 30 at the elevated end of liner 11. The bottom of trap portion 27 is formed with a port 31 which is in communication with the inlet end of a motor driven screw conveyor 32 arranged to transport coke from trap portion 27 continuously from left to right as shown in the drawing. Heat exchange means 33 for preheating feed water to the system is shown whereby the heat from coke collected in trap portion 27 is recovered to the system. As thus arranged, conveyor 32 discharges coke to pass downwardly through the coils 34 of heat exchange means 33 and out the bottom at 35. Coils 34 are connected at one end to a feed water pump 36, pumping feed water from a reservoir into coils 34 to supply same in heated condition to line 22 via the valve 37.

At the upper region of trap portion 27, there is provided an outlet 38 whereby the vapors and volatiles pass to a condenser means 39 serving to recover volatiles entrapped in the steam, for example, such as tar, etc.

Operation of the system shown in the drawing is as follows: Coal is crushed to a size on the order of *3 ring mesh and is transported by conveyor 24 for introduction into the elongated passage 11. Superheated steam is generated in chamber 21 and injected upwardly along the inclined passage through the raw coal in liner 11.

In one example, the coal was bituminous, crushed to pass a ring mesh, and the temperature of the steam was 850 C.

The steam injected through the coal serves to release substantially all the volatile constituents rather quickly in the hot atmosphere. With a 16 Particle size, penetration of heat into the center of the particle is effected very quickly. As the steam agitates the deposit of coal within passage 11, the lower specific gravity of coke as it is formed serves to separate it from the coal and move it more quickly upwardly along the inclined passage. Thus, the coke is carried along or entrained in the stream of steam faster and farther than the uncoked coal and the angle of incline serves to separate the coke from the coal. It is believed that as the coal is converted to coke, it absorbs heat at first until the major part of the volatiles have been broken down. At this point, an exothermic reaction is believed to take place which hastens the coking process and finishes it off quickly.

As the coke reaches the trap portion 27, it passes over sill 29 and, due to the slight drop in velocity caused by 3 enlargement of the enclosure, falls into the inlet end of conveyor 32. Conveyor 32 then transports the coke from left to right as shown in the figure until it is discharged down through heat exchange means 33 where the heat of the coke serves to preheat feed water being pumped along line 34.

The released volatiles and steam vapor escape along the upper region of trap portion 27 via outlet 38 into a condenser 39 where the volatiles are recovered as a byproduct. By using steam distillation, the coking temperatures are able to be much lower than in a standard coking procedure where heat is applied from the outside.

Inasmuch as the steam pressure is just enough to overcome the back pressure from the released volatile vapor as well as to carry the solid particles up the incline, it will be readily apparent that various angles of incline will cause variations in the pressure required. Furthermore, it will be equally obvious that the extent of the elongated passage 11 necessary for complete coking will vary to some degree with the temperature of the steam being utilized. Accordingly, the above example is considered exemplary only and the invention is to be limited only by the scope of the following claims.

I claim:

1. In a process of coking crushed coal, the steps of introducing the crushed coal into an enclosed and substantially unobstructed passage inclined at a predetermined angle, said passage being open at the elevated end to discharge material therefrom, injecting super-heated steam under pressure into the lower end of said passage to coke the coal thereby reducing its density, and to transport the coke formed, to the substantial exclusion of the coal, up said passage faster and farther than the coal, and collecting said coke substantially exclusive of coal from the elevated end of said passage.

2. A process of coking crushed coal as defined in claim 1 wherein the velocity of said steam in said passage with respect to the density of the coke is sufficient to transport the coke up said passage while being insufficient to so transport the coal, said coal being held back by the angle of incline of the passage.

3. In a process of coking coal as defined in claim 1 wherein the coal is crushed to a size to pass on the order of a & inch ring mesh.

4. Apparatus for preparing coke from coal comprising an enclosure including an elongated portion forming a substantially unobstructed passage extending therealong, said portion being formed to incline said passage at a predetermined angle to the horizontal, said portion having an opening in the elevated end of said passage, insulation around said elongated portion, said enclosure further having a trap portion disposed in communication with said opening, said trap portion including a hopper-like chamber having a wall thereof disposed to form a sill with respect to said opening, said chamber having an outlet adapted to exhaust gases therethrough, the bottom of said chamber having a port therein adapted to pass coke therethrough, means disposed at a region in said elongated portion remote from said opening for introducing coal into said passage, and means for injecting a continuous stream of super-heated steam under pressure into said passage to release volatiles from said coal and convert said coal to coke whereby said coke is separated by density from the coal and transported up said passage and into said chamber to the exclusion of the coal and whereby said volatiles are entrained by said stream to pass via said outlet to be exhausted from said trap portion.

5. A closed system for preparing coke from coal comprising the apparatus defined in claim 4 further including heat exchange means disposed with respect to said steam injection means to transfer heat thereto from coke passing through said heat exchange means, and conveyor means interposed between said port and said heat exchange means to transport coke from said trap portion to said heat exchange means whereby heat lost during cooling of said coke is regained by said system.

References Cited by the Examiner UNITED STATES PATENTS 2,586,703 2/1952 Odell 202--17 FOREIGN PATENTS 104,346 6/1938 Australia. 119,040 2/ 1919 Great Britain.

MORRIS O. WOLK, Primary Examiner.

Claims

4. APPARATUS FOR PREPARING COKE FROM COAL COMPRISING AN ENCLOSURE INCLUDING AN ELONGATED PORTIONN FORMING A SUBSTANTIALLY UNOBSTRUCTED PASSAGE EXTENDING THEREALONG, SAID PORTION BEING FORMED TO INCLINE SAID PASSAGE AT A PREDETERMINED ANGLE TO THE HORIZONTAL, SAID PORTION HAVING AN OPENING IN THE ELEVATED END OF SAID PASSAGE, INSULATION AROUND SAID ELONGATED PORTION, SAID ENCLOSURE FURTHER HAVING A TRAP PORTION DISPOSED IN COMMUNICATION WITH SAID OPENING, SAID TRAP PORTION INCLUDING A HOPPER-LIKE CHAMBER HAVING A WALL THEREOF DISPOSED TO FORM A SILL WITH RESPECT TO SAID OPENING, SAID CHAMBER HAVING AN OUTLET ADAPTED TO EXHAUST GASES THERETHROUGH, THE BOTTOM OF SAID CHAMBER HAVING A PORT THEREIN ADAPTED TO PASS COKE THERETHROUGH, MEANS DISPOSED AT A REGION IN SAID ELONGATED PPORTION REMOTE FROM SAID OPENING FOR INTRODUCING COAL INTO SAID PASSAGE, AND MEANS FOR INJECTING A CONTINUOUS STREAM OF SUPER-HEATED STEAM UNDER PRESSURE INTO SAID PASSAGE TO RELEASE VOLATILES FROM SAID COAL AND CONVERT SAID COAL TO COKE WHEREBY SAID COKE IS SEPARATED BY DENSITY FROM THE COAL AND TRANSPORTED UP SAID PASSAGE AND INTO SAID CHAMBER TO THE EXCLUSION OF THE COAL AND WHEREBY SAID VOLATILES ARE ENTRAINED BY SAID STREAM TO PASS VIA SAID OUTLET TO BE EXHAUSTED FROM SAID TRAP PORTION.