US1944872A - Method of coking heavy petroleum residues or the like - Google Patents

Description

Jan. 30, 1934. c. w. ANDREWS 'Er AL 1,944,872

'METHOD OF COKING HEAVY PETROLEUM. RESIDUES 0R THE LIKE Filed Des. 11, 192s s sheets-sheet 1 Jan'. 30, 1934. c. w. ANDREWS ET AL 1,944,872

METHOD 0F COKING- HEAVY PETROLEUM RESIDUES 0R THE LIKE Filed Dec. 11, 1929 s sheets-sheet 2 y @Mw/21@ Jam 30, 1934 c. w. ANDREWS r-:r AL 1,944,872

METHOD OF COKING HEAVY .PETROLEUM RESIDUES 0R THE LIKE W l E@ w w 7 I l ha l UD I D L 3% n u n v" D #wr ,b n n/-Jwu j h w D I n 'n ig @D D l D %W D QU I n n n l? l n MHH {B-@YQ (n n i D n n n `Patented Jan. 30, 1934l STATES PATENT OFFIC METHOD OF COKING HEAVY PETROLEUM RESIDUES OR THE LIKE Application December v1li, 1929 Serial No. 413,207

3 claims. (ci. 2oz-i7) hydrocarbons Ain liquid form.

In our prior Patent No. 1,805,711 granted May 19, 1931, we have shown 'a form of oven heated from below by flues under the sole of the oven,

. which oven is adapted for the coking of heavy residues of this character, the volatile constituents of the residues being driven off and. collected as oils of lower viscosity than the residue being treated. This type of'chamber, however, re-

quires that except for the sensible heat of the feed, all of the heat for the reaction be lpassed through the floor of the oven and also through the layer of coked material which forms on the oven floor. This method of applying the heat gives a very desirable metallurgical coke, but is comparatively slow.

It is an object of this present invention to provide a new and improved method whereby the heat, or 'a large portion of the heat, necessary for carrying on the coking operation may be supplied internally of the coking chamber.

It is an additional object to provide a' method wherein this heat may be provided by means of partial combustion of the material within the chamber.

It is a further object to provide a method in which internal heat may be supplied in whole or in part by products of a combustion carried on externally of the chamber and with, or without,- secondary combustion in the chamber.

It is an additional object to provide a method whereby the internal heat necessary for coking may be provided in the chamber with, or without, the application of additional heat through the i'loor or sole of the oven.

It is also an object to provide a method in which the residue being treated and the oxygen or oxygen-containing gas are intimately mixed so as to produce an'effecti've combustion.

It is an additional object to provide a method of this character in which additional heat may be supplied -if desired through the iioor of the oven in which the operation `takes place.'

It is also an object to provide a method in which the waste heat of the process may be utilized for preheating the incoming carbonaceous material and air.

It is a further object to provide a chamber in which the coke is continuously formedand continuously removed.

Other and furtherl objects will appear as the description proceeds.

We have shown somewhat diagrammatically in the accompanying drawings, certain preferred embodiments of an apparatus adapted for carrying out our improved method.

In the drawings- Figure 1 is` alongitudinal section of the apparatus; c-

Figure 2 is a transverse section of the ap paratus;

Figure 3 is a plan View of the apparatus;

Figure 4 is a horizontal section showing the floor of a modified form of oven; and

Figure 5 is a longitudinal section of the oven of Figure 4.

In the drawings, referring first to Figures 1 to 3, the oven chamber 11 4is provided with the floor 12, preferably formed of refractory material, and which is heated from below by combustion taking place in the ues 13. These flues 13 may be heated' by gas or liquid fuel introduced through nozzlesv 14, controlledv by valves 15. These nozzles are provided at both ends of the flues 13.

'Ihe passage 16 serves to introduce the air which passesl up through the heating flues 17 andthrough passage 18 into the combustion flues 13. The center of the construction is provided with the passages 19 for carrying 01T the products of combustion which pass to the offtake passage 21.

As shown in Figure 3, the products of combustion may pass olf through the offtake header 22 and through the recuperator or heat transfer apparatus 23, for the purpose of preheating the incoming oil or residue. The products of combustion may also pass through the v recuperator or similar heat interchange apparatus 24 for preheating incoming air or steam, and from the apparatus 24 through passage25 to the stack 26.

The upper portion of the oven chamber 11 is closed by the housing 27 which is provided with a'dome 28 and an offtake passage 29 which serves to carry on the volatilized constituents of the material being treated. The material being treated is introduced through the nozzles 30, the heavy liquid hydrocarbon being introduced through the pipes 31 controlled by valves 32. These pipes 31 lead from the oil header 33. The air or steam under pressure may be introduced into the nozzles 30 through pipes 34, the supply being controlled by valves 35. An air or steam header 36 is provided connecting the several pipes 34. As shown in Figure 3, the oil valves 32 are connected by pipes 33 with the oil or residue preheating apparatus 23 into which the oil is introduced through pipe 38. Similarly, the compressed air or steam headers 36 are connected with the air heater or steam superheater 24. The air or steam may be introduced into the heater 24 through pipe 40, which' may be connected to any suitable apparatus for providing a supply of compressed air or steam.

The pipes 41 connect the offtake passage 22 with the nozzles 42, the pipes being controlled by valves 43. The nozzles 42 are shown as extending into the cover of the chamber 11. These nozzles or ports 42 surround the smaller nozzles` 30, which may act as inspirators to draw the ilue gases from the passages 41 into the oven chamber 11 should the pressure in the offtake passage 22 not be suicient to deliver the desired amount of flue gases, or should the suction in the chamber 11 be insufficient to draw in the desired amount of flue gases.

Non-oxidizing gases may be introduced through pipes 44 controlled by valves 45 to equalize the temperature of the incoming gases from the flues 21, or gases similar to the noncondensible gases produced by the operation of the process may be introduced `through these pipes under sufficient pressure to inspirate the flue gases into the chamber when this is necessary.

Referring now vto the form of construction shown in Figures 4 and 5, the chamber 50 is provided with the oor 51 having a series of openings 52 which communicate with the longitudinally extending ues 53 located below the floor 51.

In the form of construction shown, these i'lues` extend the full length ofthe oven and alternate ues are provided at opposite ends of the oven with burners 54 for the introduction of combustible gas or liquid fuel. 'Ihese burners 54 are fed with fuel through headers 55. The air necessary for combustion is introduced from air headers 56 into lower passages 57 wherein the air is some what preheated by radiation from the superposed combustion flues. From the lower flues 57 the air passes through openings 58 and 59 into the combustion flues 53.

The top of the chamber 50 is provided withthe offtake 60 for the gaseous products of the process. Each end of the chamber 50 is provided with the cross shaft 61 carrying sprocket wheels or the equivalent 62. One or both of Athese wheels 62 may be power driven and the continuous conv veyor 63 is carried over the two wheels 62. This conveyor consists of a series of interlinked pans V64 which have their open side upperward on the since partial combustion is the essential feature,

this gas may be pure oxygen or any gas containing a sufficient percentage of oxygen for the purposeintended. If oxygen is used alone, it will be V apparent that the gaseous products of the process will be of higher B. t.- u. value than when air is used, as the products will be substantially ni= trogen free. f

We have found by long experimentation that if the residue is used just as it comes from the vaporizer of the usual oil treatment apparatus, at a temperature of approximately 700 F. the process may be carried on to advantage without additional preheating of the residue before itis introduced into the chamber. The heat interchanger 23 for the preheating of the oil or residue is of particular importance where the residue is not received at relatively high temperatures.

It will be understood that this' invention is applicable to the treatment of residues of such a character that they are solid at normal temperatures, and in this case, if cold residue is treated it will be necessary to preheat it suiilciently to bring it to a liquid state before passing it through the heat interchange apparatus 23. Where the residue is introduced with an oxygen-containing gas according to one nner of carrying out our invention, it is found desrable, though not absolutely essential, to preheat the gas prior to its admixture with the residue. This preheating reduces the amount of gas and the amount of combustion necessary to produce the desired coking temperature in the coking chamber.

For certain purposes and with certain types of heavy hydrocarbons it may be undesirable to allow partial combustion of the hydrocarbon itself. Combustion may render some or all of the condensible volatilesv undesirable for certain purposes.

Our method may be carried out without material combustion of the hydrocarbon being treated, by the use of the pipes 4l and nozzles 42. In this manner of carrying out our method the heavy hydrocarbon may be introduced alone or maybe sprayed in with steam or any non-oxidizing gas. through nozzles 30.

The internal heat may then be had from the nozzles or ports 42, which receive products of combustion through pipes 41. These products of combustion may be used merely for their sensible heat. These gases will be highly heated and will normally be above a coking temperature. If additional heat is desired, these gases may be only partly burned in the ues below the floor and additional air for a secondary combustion may be introduced through the pipes 34 controlled by valves 35. If the flue gases are too hot, their temperature may be reduced by supplying cooler gases through pipes 44, controlled by valves 45. Gases .under pressure may be supplied through these pipes 44 to draw the flue gases through the ports 42.

While the heating of the floor of the oven is not absolutely essential in these methods of operation, it is found desirable to maintain this floor at substantially a coking temperature at the time of introduction of the first portion of the material being treated. This avoids chilling the material and starts the process without delay. After a layer of coke has been formed on the floor, the process may be interrupted and the coke pushed vor drawn from the chamber. The coke formed may, however, be continuously removed by a suitable scraping device so that the process may be continuous.

The nozzles 30 should be such as to bring about an intimate mixture between the residue and oxygen or oxygen-containing gas when this is used, so that the combustion takes place rapidly and uniformly without overheating portions of the material. The amount of oxygen used when the oil is introduced at comparatively high temperatures may be only a very small percentage of the oxygen which would be necessary for complete combustion. The actual combustion may be, therefore, very slight and can be held at such a point that the oils drawn oi have substantially no objectionable oxidation odors. While the material is sprayed into the oven, it has been found in operation that the residue is not deposited as coke dust, but forms a definite solid layer of' coke which is firm in structure and suitable for commercial purposes.

The volatile'constituenis of the material being treated are drawn off from the upper portion of the chamber through the dome 28 and passage 29 and may be taken to any usual apparatus (not shown) for the treatment of such gases and vapors. For example, they may be passed through fractionaiing towers where `the dierent fractions may be condensed and the fixed gases remaining will be found to have a very high B. t. u. value. For example, with cold air and warm oil, a gas has been produced which runs from 350 to 400 B. t. u.s per cubic foot. On the other hand, where the air is preheated and the oil is at a higher temperature, it is unnecessary to introduce so much air for voxidation and consequently the nitrogen content of the gas is lower and a gas of from 500 to 600 B.y t. u.s or even higher may be produced. Y

In carrying out our method of operation with the form of apparatus shown in Figures 4 and 5, it willbe understood that the chamber 50 will be heated both by radiated heat from the oor 51 and by the gaseous products of combustion which will pass through openings 52 up against the under side of the pans and through the chamber 50, and pass oi through oitake 60 with the gases and vapors formed in the process. The material to be treated is fed into the pans 64 through ythe nozzles 65.

It will be understood that the movement of the conveyor may be intermittent or continuous,-

as desired, In one form of operation, for example, the conveyor might be given a step by step movement with a predetermined amount of the material to be treated fed into each pan as it is halted under that particular nozzle. The spacing between nozzles 65 might be sufficient so that the time of movement between the nozzles would permit the material deposited by one nozzle to be coked before material is deposited in the same pan by the next succeeding nozzle. Thepans 64 may be so overlapped at their adjacent edges that the movement of the pan conveyors may be continuous without loss of material between pans and may be at such a rate as to cause the pan to secure the desired amount of material below each nozzle which may discharge continuously.

The alternate flues 53 are ilred from opposite ends so as to give a substantially uniform heating to the oor and to give a substantially uniform discharge of hot gases through the openings 52 in the oor. The openings 52 are located toward the far end of each ue 53, or the end distant from the nozzle in that ilue.

In the form of construction shown in Figures .1 and 3, a flat oor, is used while in the form of Figures 4 and 5, pans are used whichmay have substantially flat bottoms or surfaces for receiving the material. Other forms of flat or approximately flat surfaces may be used where they accomplish the desired result. This may include large types of cylindrical stills which are placed horizontally, so that the bottom surface inside the stills may be somewhat curved we contemplate such changes and modications as come within the spirit and scope of the appended claims.

We claim:

1. The method of treatment of heavy hydrocarbons in liquid form, which comprises spraying the hydrocarbon together with an oxygencontaining gas into a'closed chamber, thev chamber being at approximately atmospheric pressure, the temperatures of the liquid and oxygen being such as to cause partial combustion of the liquid, thus raising the temperature of the liquid to such a point as to drive oi the volatile portions of the liquid and progressively deposit a solid carbonaceous residue upon the floor of the chamber, the residue being in the form of coke, externally heating the iioor of the chamber to approximately a coking temperature, and periodically interrupting the introduction of the hydrocarbons and withdrawing the formed layer of coke.

2. The method of treatment of heavy hydrocarbons in liquid form, which comprises continuously introducing the liquid into a. closed chamber at approximately atmospheric pressure, depositing the liquid in a substantially horizontal layer therein, -introducing heated gases into the chamber, the gases being at substantially a. coking'temperature, thus raising the temperature of the liquid to such a point as to drive off volatile portions of the liquid and progressively deposit a solid carbonaceous residue upon the iloor of the chamber, the residue being in the form of coke, externally heating the floor of the chamber to approximately a coking temperature to assist the formation of the coke thereon, and

periodically interrupting the introduction of the liquid hydrocarbons and withdrawing the formed layer of coke.

3. The method of treatment of heavy hydrocarbons in liquid form, which comprises continuously introducing the liquid into a closed chamand gases being at such temperatures and the 150 oxygen being in such quantity as to cause partial combustion of the liquid to raise the temperature of the remainder of the liquid to such a point as -to drive off volatile portions of the liquid and progressively deposit a solid carbonaceous residue upon the oor of the chamber, the residue being in the form of coke, externally heating the oor of the chamber to approxi-

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