DE1054450B - Process and device for the conversion of hydrocarbon residue oils - Google Patents

Description

Process and apparatus for the conversion of residual hydrocarbon oils The invention relates to a method and a device for converting heavier Hydrocarbon oils at high temperatures for the production of, in particular, unsaturated ones Low molecular weight hydrocarbons, weight and coke. But especially so The invention relates to a method and a device in which fine powdery, heated, catalytically relatively inert, solid particles to achieve the desired Conversion can be used.

A number of proposals for conversion have been made earlier heavy hydrocarbon oils into relatively valuable olefins and diolefins made with 2 to about 6 carbon atoms. These processes are also used for the manufacture of benzene and homologous aromatic hydrocarbons as well as of paraffinic ones Suitable for hydrocarbons and hydrogen. In recent years the demand has increased for such products as ethylene, propylene, butadiene, isoprene, benzene and the like. increased significantly. These compounds are in particular starting materials for Manufacture of various chemical products, including pole sleeves. Different Plastics, synthetic fibers, etc. as well as simpler chemical compounds and Solvents can be obtained from these starting materials. Therefore, the low molecular weight unsaturated compounds as basic chemical substances for the production of numerous Industrial products, including synthetic fibers, plastics, and others Pol_vineren, etc., can be considered.

It has long been known that cracking heavy hydrocarbon oils, For example, from petroleum or coal tar residues and the like, different unsaturated Can obtain products in good yields. Following a procedure of this type brings one preheated, solid particles with the oily charge together, which thereby is thermally converted into the desired products. The products are then separated from the solid particles and by contact with a liquid coolant cooled down. The solids are returned and heated to meet the heat demand of the system to cover.

The method according to the invention is similar to this in several respects The method described above, however, has a number of improvements over this on. The subject of the present invention is the effectiveness of the conversion to improve and thereby the cheapest yields from inferior heavy oils to achieve low molecular weight products, as they are desired here. this is achieved through the appropriate choice of operating conditions as well as through a number of associated work stages achieved, which is an improvement over the previous process represent.

The invention also encompasses more efficient apparatus for practicing the procedure described above.

The invention has a number of important features. She concerns the conversion of heavy oils at high temperatures, preferably at least 650 up to 815 ° C or more, with a temperature range of 675 to 760 ° C preferred will. Particularly beneficial for producing the desired low molecular weight products is an operating temperature around 700 ° C.

Another important feature of the invention is the regulation of the Hydrocarbon partial pressure within the system to ensure high yields on the most popular products. This is preferably achieved in that a relatively inert gas free of hydrocarbons into the reaction zone introduces. The preferred diluent is superheated steam, though nitrogen, flue gases, or other inert diluents can also be used.

The reaction time, that is the time during which the oil is in contact with the heat transferring particles, is very short and is usually less than 2 seconds. At 700 ° C, the preferred residence time is generally about 0.5 seconds. At a lower temperature it is a little longer and is z. B. at 690 ° C about 1 second. At higher temperatures, the residence time should usually be shorter. The invention also comprises the use of a highly effective separating device for mixtures of steam and esters, in order to enable separation within a certain minimum time. This separation time should not be more than 1 second, preferably but less. As a rule, it should be shorter than the reaction time and, at a preferred temperature range of 690 to 730 ° C., it should not be longer than about 0.1 to .25 seconds. At higher temperatures, the separation time should be even shorter.

Another factor is the quick and effective deterrence of the Steam products after separation. The deterrent should happen very quickly marry, d. H. within 1 second or less immediately after the vapors from the heat-carried solids are separated. The vaccination products are frightened most expedient starting by doing ie within 1 second or less after detachment cools by at least 140 ° C. It is preferable to make the products even stronger, i. H. around a few 00 'C, e.g. B. to 315 to 370 ° C, to cool ine thermal decomposition to prevent.

Another feature of the invention consists in [he heating the the '' heat for converting solids by burning combustibles Substances within a very short period of time in the presence of these solid particles. It was found that as the incineration time was increased, there was left on the particulate matter carbonaceous residues deposited or formed by these particles with the carbon dioxide produced during combustion, with considerable loss convert to carbon monoxide in sensible heat. It is (it is semi-important that the fixed Substances within less than 3 seconds, preferably in less than 5 seconds, be heated up by the combustion process.

In this way the conversion to the carbon dioxide is at its highest increased and a good heat utilization achieved. It is best to go through the segregation time hold under 1 second.

The invention is further characterized by improved extraction and fractionation systems as well as control systems through which the billing of so-called "dry" gases, d. H. of hydrocarbons with 3 carbon atoms and less, between about 25 and 40 weight percent, it can hold oil charge. Usually the proportion of dry gas in the conversion is around 30%.

The invention will now be explained in more detail with reference to the drawing.

Fig. 1 of these drawings is an elevation (with certain parts omitted are) a coking plant suitable for carrying out the method according to the invention; Fig. 2 is an enlarged view of the reaction chamber, the separator and the Quenching device and its parts, as shown in the middle part of Fig.l, with certain parts omitted and others shown in section; Fig.3 is a diagram and shows the influence of the hydrocarbon partial pressure on the formation various products in high temperature cracking.

There now follows a detailed description of the device on the basis of the drawings. A stream of solid particles previously on preferably have been heated above 760 ° C., passes through a downpipe 11, a U-pipe 13 and a tube or riser 15 provided for upward guidance into an elongated one Reaction Chamber 17. The rate of flow through this chamber and its size are sized so that the particles averaged the chamber in no more than 2 seconds through completely. Preferably the speed is such that the particles only take about 0.5 seconds on average to pass; however, it can be lower at higher temperatures. At a reaction temperature of 700 ° C is the superficial velocity of that containing the solid particles Current preferably 3 to 15 m / sec. with a length of the reaction chamber from 6 to 15 m.

The risers described above are vented to remove the solid particles by injecting steam from one or more groups of nozzles 19, 21 and 23 to wear upstairs. Another fluidizing gas is introduced through inlet 25, preferably steam, introduced into reaction chamber 17; however, there are others too inert gases, as mentioned above, are suitable. By regulating the steam flows into the different, mentioned lines you can determine the correct speed of the flow of solids and set the required partial hydrocarbon pressure in the reaction chamber.

The oil to be converted is introduced through a conduit 27 into a nozzle or nozzle assembly 29, which is preferably annular, so that the oil feed is evenly distributed over the entire cross-sectional area of the reaction zone. In this way the stream containing the solid particles is uniformly brought into contact with the feed oil. The charge, which can be heated beforehand, but is still largely or almost entirely in the liquid state, is injected with great force through the nozzle 29 so that it is well distributed and disintegrates into fine droplets or particles.

In this process, the temperature of the line 15 in the solid particles flowing into the reaction chamber are about 760 ° C. In the first contact with the oil, the temperature in the chamber can be around 745 ° C, while it is much lower on the exit side of the chamber and z. B. is around 700 to 705 ° C.

The reaction chamber opens into a cyclone of special design, which is shown in more detail in Fig.2. As can be seen from Figure 2, the reaction zone ends in a spiral downward leading and conical, outer part 31, which the outer wall of the cyclone or separator forms. When looking at the in Fig.2 shown one would see how the entering, from solid Particles and steam existing stream z. B. rotates clockwise and at a Downward movement towards the center converges. Located within part 31 a truncated cone 33 forming the lower end of the outlet line 35, the has a large number of holes at the bottom large enough for a quick escape of gases and vapors as indicated at 37.

Due to the centrifugal force, the solid particles are around the inner Surface of the truncated cone around, along the outer wall and then flung down, while the vapors rush up through the holes at great speed and pass through line 35 into a recovery plant to be described. By the line 39, a quenching liquid is fed into a preferably annular one Manifold 41, which is arranged so that the spray jets of the quenching liquid distributed in the escaping vapors and brought into intimate contact with them will. The spray jets are preferably directed upwards as shown, however, it can also be directed downwards. If necessary, the outlet line can also be used lead down. A branch line 43 of the supply line for the quenching liquid leads down to the lower end of the truncated cone 33 or close to it. This branch line carries a number of upwardly directed branch nozzles 45, so that cooling jets can also be sprayed into the vapors as soon as they enter the outlet line reach. You can change the arrangement of these nozzles a little, in any case But what counts is a quick and effective deterrent to decomposition to prevent the vapor products.

The quenchant can be a cooling liquid, such as water or oil, or a suspension of chilled, solid particles in a suitable liquid, as is well known in the art. However, it is preferred to use an oil with a boiling range between that of the low molar products and that of the starting charge of the process. A particularly suitable quenching liquid is e.g. B. represent an oil fraction with a boiling range of over about 200 up to 400 ° C. In most cases, oils boiling up to 480 ° C can be used for this, but mostly oils that are not quite as heavy are used. The liquids are introduced at such a rate that the temperature of the product vapors decreases within 1 second by at least 1100 C, preferably not less than 140 ° C.

Appropriately, however, the deterrence goes much faster, as stated above, z. B. within 0.25 seconds or less, in front of you. But it is best As mentioned above, deter even more by keeping the initial temperature from 675 ° C or more to 430 ° C or less, preferably down to 370 ° C.

The quenched vapors enter the recovery plant through line 51 53. This contains in the lower part a number of baffle plates 55 for cleaning the quenched vapors, on their way up. The condensed heavy oil can be withdrawn through the outlet line 57 at the bottom. This oil or part from this one can optionally lead back into the reaction chamber 17.

The uncondensed vapors pass upward through a series of trays 59 for further fractionation, with the condensed liquids collecting on one of the trays 61 and being withdrawn through line 63. These liquids can be returned to the top through line 65 with a circulation pump. They flow countercurrently through the rising vapors, which cools and condenses them more effectively. The vapors rising upward beyond the feed line 65 are fractionated even further in the upper part 67 of the tower, which also contains fractionating floors 69. You can also deduct different side streams. One of these streams, preferably one with a medium boiling range, can be re-injected through the nozzles 41, 45 as a quenching liquid. The non-condensed remaining gases are withdrawn through line 71 at the top. During the conversion in the reaction chamber, the carbonaceous deposits, which mainly consist of coke and which usually also contain some oil, which continuously escapes in vapor form, are deposited on the particles originally supplied to said chamber. As soon as these solid particles carrying the deposits are separated from the vapors, they fall down into a collecting space 81, where further vapors are stripped off therefrom by a stripping gas blown in from the line 83. The latter can pull upwards into the product outlet line in countercurrent due to the downwardly sinking solids or, if necessary, also be isolated by a sealing zone provided in the constriction 85. Preferably, the stripping gas is introduced through line 83 at such a rate and in such quantities that a fluidized bed of particulate matter is maintained in plenum 81.

The stripped solids flow from the plenum through the Line 89 down into the U-tube 91 and from there into the riser 93. To the Positions 95, 97 and 99 are ventilation and propulsion nozzles at intervals one behind the other, preferably arranged for steam. If you shred the solid particles a bit If you want, you can also provide high-performance nozzles here, the gas jets with very high Give up speeds. When using such jet nozzles from which gas jets leaking at high speed per second, one achieves an extremely effective one Comminution of the solid particles, especially if they consist of product coke; which is mostly the case. The speed of the ascending through line 93 solid particles is controlled by the fact that the amount of through the jet nozzles 95, 97 and 99 gas blown in accordingly.

At the upper end of the line 93 (Fig. 1) a throttle valve 101 is provided, but also at the lower end of this line or in the lower part of the standpipe 89 can be arranged.

The solids carried upwards that make up the adhering hydrocarbons are stripped and their volatile content is therefore only low are fed into a large elongated combustion chamber 105. A stream of combustion maintaining gas, e.g. B. from air or oxygen, passes through line 107 into chamber 105. If the solid particles are not themselves flammable are and / or not enough carbon to generate the required heat contain, you can still add foreign fuels together with the air. Self but if the particles consist of coke, as is usually the case, they need when it comes to the production of product coke, not to be burned. In in this case, the total amount of fuel required, e.g. B. in shape of oil or gas, supplied together with the air through line 107, or one blows portions of it in at various points on the burner. The alien fuel burns more easily, so that in this case the product coke is largely unburned remain.

As already mentioned, it is convenient to burn and reheat to accelerate the solid matter as much as possible. This is an important feature of the present invention. The burner is therefore dimensioned so that the solid particles on average in less than about 3 seconds, preferably in less than 1.5 Seconds, completely have flowed through. At a cremation camper of 18 m in length, the average speed should therefore be at least 6 m / sec. and preferably even a little more. When working at such a speed it is advisable to use an effective and rubbed at high speed To connect cyclone 109 to separate solid matter from combustion gases, which is generally of the same type as the cyclone 31 described above, 33.

The combustion gases escape after the solid matter has been separated off up through the line 111. Since this is about one driven at high speed Cyclone separator acts, it is usually appropriate to remove the combustion gases to pass through a second cyclone or the like in order to remove further fine Recover particles and adverse atmospheric pollution: u prevent. This second, not shown here #, separation device, can be one of the usual Must be.

The separated solids fall down and enter the Stripping and collecting space 113, which works in roughly the same way as that described above Collection space 81. A stripping gas can be introduced through one or more inlets 115, 117 initiate; The heated particles flow through the downpipe after being wiped off il down and are put down for use in the process in the reaction chamber returned. The product coke can be placed at any suitable point in the plant, z. B. by the one located at the lower end of the downpipe 11, with a shut-off valve 119 provided outlet line 117 can be withdrawn. Under certain working conditions the resulting coke is completely consumed for the process, so that no Coke is a by-product.

From FIG. 3 it can be seen that the generation of the particularly valuable vapor products increases very considerably when working with low partial hydrocarbon pressures. At the same time, methane, which has little economic value and is therefore undesirable as the main product, is formed at a partial hydrocarbon pressure of less than 0.7 kg / cm 'abs. back quickly. It is now most convenient from the standpoint of yield. to work with a hydrocarbon partial pressure of less than 0.7 kg / cm2. The amount of inert diluent will of course depend on your partial hydrocarbon pressure desired. The table below gives e.g. B. the steam quantities required for hydrocarbon partial pressures of 0.35, 0.7 and 1.4 kg cm2 in percent by weight, based on the charge Hydrocarbon partial pressure kg / cni2 .................. 0_, 35 0.7 1.4 Steam, percent by weight .... 130 48 6.6 The cheapest amount of steam to use depends on the cost of generating the steam and the prices of the hydrocarbon products, as well as the cost of equipment at the job site.

The mutual relationships shown in Figure 3 give the overall yields of Cl-, # C2-, C3 and C4 products again, which when loading the reaction chamber with gas oil. Those with residual oils as the starting material. received Yields differ somewhat from those shown in FIG Investigations have shown that the general tendency with changes in the hydrocarbon partial pressure is about the same. The yields shown in Figure 3 include both those in saturated as well as unsaturated carbons. Among the above, preferred operating conditions, d. H. at temperatures of around 700 ° C and contact times of preferably about 0.5 seconds or less is obtained from the C2 products Yields of 6011 / o ethylene or more. The C3 products consist of over 9011 / o from olefins, while butadiene, which is the most valuable of the C ¢ products, under these preferred conditions between 30 and 4011 / o of the total yield of these C4 products.

As mentioned earlier, the overall effectiveness of the procedure will be too largely through decomposition into "dry" gases (i.e., hydrocarbons with 3 and fewer carbon atoms). Preferably the proportion of dry gases between 25 and 40 percent by weight, based on the charge, held. A formation of about 30% methane is obvious with most starting oils the best value. You can of course also have other valuable products than the above obtained under the same operating conditions, e.g. B. C. Diolefins in pretty good yields, as well as some benzene, toluene and xylene. You all have of greater value than gas oil or gasoline for most refineries.

In a well-working method according to the invention one leads, for. B. to 815 ° C preheated solid particles together with superheated steam in the Reaction zone. The speed in the riser is prior to blowing in the Steam about 1 to 1.5 in / sec. The addition of steam increases it to 4.5 to 5.2 m / sec. The feed consisting of residual oil, e.g. B. a reduced Louisiana crude oil, is injected through the distribution nozzle ring 29 under the hot, solid particles. During the evaporation and cracking of the oil, so much gas is produced that the speed by the end of the reaction zone 19 to 18 in / sec. has risen. The dwell time of the gases in the part of the reaction chamber designed as a flow line about 0.25 seconds. The goods remain in the cyclone for about 0.25 seconds. The cyclone forms essentially the end portion of the reaction zone, and it is important that the gas, once it is separated from the solid particles, as far as possible from the solid Substances are kept away. The product vapors are on the exit side of the cyclone Moistened by spraying with cold oil and cooled to 280 ° C to the more volatile Vapors to cool and a fraction boiling at 340 ° C along with the tar as To win condensate. The abrasive oil used for this is between 220 and 350 ° C boiling, recycled fraction from the fractionation column. The ones from the Solid substances separated from gaseous products are steamed in a stripping zone freed from volatile components. The residence time of the solids in this Zone is about 10 seconds. A steam velocity of 2 V / V in the stripping zone sufficient to prevent major losses of steam products; otherwise 2 or 3% of the product vapors are carried into the heating zone.

When entering the heating zone, those coming from the stripping zone are solid substances mixed with air and burned. The solid particles reach within from about 1.5 to 2 seconds a temperature of 815 ° C, and the burner is for an exit speed of 18 m / sec. built. The heated solid particles are in a high gas velocity operated cyclone 109 separated from the combustion gases. The heat of these flue gases is in one (not shown here) waste heat boiler recycled. Falling out of the aforementioned cyclone the solid particles then descend into the stripping chamber 113, in which the volatile constituents be stripped with steam to avoid exhaust gases into the reaction chamber reach. In the embodiment shown in Fig. 1, part of the flows through the line 83 blown stripping steam up into the outlet line 33 bis 35. This steam, together with that, makes the solid particles as they enter steam fed to the reaction chamber, totaling about 5 percent by weight of the oil feed the end.

For example, if a 2.4% South Louisiana residue oil is used as feed at a reaction temperature of 700 ° C and 30% conversion into hydrocarbons with 3 carbon atoms and less and a hydrocarbon partial pressure of 0.35 kg / cm2 receive the following products: Product yields - weight percent Not composed of hydrocarbons Gases .......................... ... 0.9 HH4 ................................ 6.3 C2 H4 .. ............................. 10.3 C2 H6 ............................... 2.8 C3 H6 ............................... 8.5 C3 H8 ............................... 0.6 C4 H6 ............................... 2.24 C4 H8 ................ ............... 4.1 C4Hlo .............................. 0.1 C boiling at 220 ° C, products (without Benzene) .......................... 17.2 Benzene ............... . . '''**** ...... 8.83 Products boiling between 220 and 345 ° C 7.2 Residue, including coke ...... 38.4 Of course, the above example represents only one of the various possible embodiments. The method is feasible and highly effective within the limits given above. If the conditions prescribed here are complied with, z. B. convert inferior reduced crude oils with good yield into high quality products.

Claims (4)

PATENT CLAIMS: 1. Process for converting residual hydrocarbon oils into more volatile hydrocarbons containing substantial amounts of C2 to C4 olefins and coke, by contact with hot, catalytically inert, finely divided solids and a gas which does not contain hydrocarbons and which is practically inert to them 650 ° C and above, at a pressure of 0.8 to 3.5 ata and a contact time of less than 2 seconds, in an elongated flow-through reaction zone, characterized in that the oil in finely divided form, preferably in the liquid state, in a Introducing suspension of these solids in the inert gas, the oil and the gas being introduced at such a rate that the hydrocarbon partial pressure remains below 1.4 ata that the mixture is brought into a fast-acting separation zone after passage through the reaction zone to separate entrained solid particles from the vapors and then un quenched indirectly by at least 110 ° C, the separation and. the quenching may take a maximum of about 1 second. 2. The method according to claim 1, characterized in that that the inert gas containing no hydrocarbons is superheated steam used that in a lot of. 5 to 150 percent by weight, based on the amount the oil feed, is introduced. 3. Apparatus for carrying out the method according to claim 1, characterized by a flow reactor (17) with a vertically upwardly extending section, through a feed line 15 for introducing a stream of fluidizable solid particles, through feed devices (27), for spraying oil in finely divided form to bring it into contact with said upwardly directed stream of fluidizable particles in said vertical section, through conduits (19, 21, 23, 25) for supplying a fluidizing and diluting gas into the vertical section, but below the feed means for the 01, to assist the upward passage of said particles through the reactor (17), through means for adjusting the speed of said oil and the diluent gas in the reactor, through a fast acting cyclone separator for separating gases and solids at the end of the reactor (17), this separator having an outer wall u ng (31) of a spiral cross-section in plan and an inner, downwardly narrowing perforated frustoconical baffle wall (33) which is connected to an upwardly leading steam outlet line (35), through a downwardly directed solids separation space (81), by means (83) for stripping the vapors from the solids falling down in this separator, through a flow burner (105) for reheating the thus separated solid particles, a cyclone separator (111) operated at high throughput and of the same type as the cyclone adjoining the reaction zone, a solids separation space for the reheated solids particles (113) and lines (11, 13 and 15) for returning the reheated solids to the reactor. 4. Apparatus according to claim 3, characterized in that in the Steam outlet line (35) Spray devices (39) for quick quenching of the vapors are provided. Publications considered: German Patent No. 938 844; British Patent No. 700309; U.S. Patent No. 2,437,334.