DE1018041B - Process for regenerating hydroforming catalysts - Google Patents

Description

Method of Regenerating Hydroforming Catalysts The invention Refers to the regeneration of catalysts used in fluidized bed hydroforming be used.

It has already been proposed for such a procedure, the Kaltalystor to regenerate continuously in a separate zone. However, the company had to do this from selectivity considerations to low catalyst-oil ratios (approx. 1: 1) be restricted. because higher ratios lead to excessive carbon deposition lead .. In addition, high regeneration temperatures were due to the steam deactivation of the catalyst not possible. These disadvantages limited the possibility of heat transfer from the regenerator to the reaction chamber by means of the circulating catalyst, and you had to go out dissipate heat from the regenerator and provide ovens or other facilities to to supply heat to the reading chamber.

According to the invention, these shortcomings can be overcome by eliminating such Catalysts based on fluidized bed technology and countercurrent to those containing oxygen Regenerating goose regenerated. Most of the time is on the catalytic converter or the deposited coke chemosorptively bound hydrogen at relatively burned off at a low temperature and the water vapor formed immediately by the regeneration gases removed. This results in the deactivation of the catalyst by steam reduced to a minimum. because the hydrogen is already in the first zone is burned off at the lowest temperature and, as a result, very little water vapor is present when the catalyst is then higher in the regeneration zones Temperature reaches. In this way, a large part of the available heat can pass through the circulating catalyst can be transferred directly into the reaction chamber. The residence time in the zone or zones of high temperature can thus be kept short. white is necessary to burn off the carbon, so that the deactivation of the Katlaysators minimally bleidt. If you wish, you can use part of the regeneration heat to: r preheating of the feed and / or the cycle gas in. direct or indirect Exchange. use. it is also possible to pretreat the catalyst with recycle gas Provide a special zone before the gas flows back into the reaction chamber.

Suitable catalysts are oxides of metals from VI. Group like Molybdenum oxide, chromium oxide or tungsten oxide or mixtures thereof on a carrier, such as activated clay and tin calcium spinel. One can also use platinum and palladium use catalysts. Most of the catalyst particles are classified through screens of 80 and 160 meshes / cm and has a diameter of up to about 200 Microns, most of which is generally between 20 and 150 microns.

In the drawing is one. Embodiment of the lying. invention shown.

The fresh feed, which contains an untreated petroleum, fission fractions, Products of the Fischer-Trospch synthesis or the like. Can be. is under pressure and. after pre-heating to the desired temperature through pipe 14 suitable Nozzles 15 supplied. the in. near the perforated plate or the distributor screen 16 are provided in the bottom part of the reaction chamber 10. The catalyst becomes the bottom handle the reaction chamber 10 in a finely divided state ill.

Suspension in a hydrogen-containing gas, advantageously a hydrogen-rich one cycle gas, supplied below the perforated plate 16 through pipe 17.

The plate 16 distributes the catalyst and the gas evenly over the entire cross section of the reaction chamber. The fumes of the loading and that Hydrogen-containing gases are mixed with a velocity of about 0.06 to 0.27 m / scc, depending on the pressure, passed upwards through the reaction zone. The: Speed should, for example, be at a pressure of 13.6 to 17 at overpressure below 0.18 m / sec. It should be sufficient to create a dense, turbulent, fluid-like Fluidized bed. 18 of catalyst particles and gas to form., Their height and at the same time Interface against a dilute phase of a suspension rod with 19 bieze.idlnelt is. This phase above the fluidized bed: is a suspension of solids in product vapors. At higher pressures, lower gas velocities opportunities chosen to form the fluidized bed. To avoid contact between the hydrocarbon vapors and to improve the catalyst, can. the reaction chamber 10 with several horizontally or vertically arranged, perforated baffle plates.

In the reaction chamber 10 is a vertically arranged tube 23 in order to withdraw the catalyst mass directly from the fluidized bed 18. The ol> e're end of the pipeline 23 extends over the edge 18 of the fluidized bed out and is on one or more. places with openings or outlets 24 equipped, through which the catalyst from their layer 18 into the pipeline can flow. Since the catalyst and hydrocarbon vapors of the reaction chamber 10 fed in the lower part and. the product vapors overhead and the catalyst in the upper. Part of the Sdiidit 18 are withdrawn, the hydrocarbon vapors flow through and the catalyst and the reaction chamber 10 are generally in the same direction. The opening 24 can be arranged in the upper part of the layer 18, so that the common Away from the catalyst and oil vapors through the layer 18 is as long as possible and that direct flow into the catalyst particles introduced into the layer 18 Pipeline 23 remains miniumal. Meanwhile, the opening 24 should because of the normal Fluctuations in height of the vertebral layer lie sufficiently deep below their level 19. You can provide more than one opening at different heights of the pipeline 23, and each opening can be equipped with valves to the bottom of the catalytic converter into the pipeline 23 to control.

By pipeline 26, which is in the. lower part of the tube 23 münsndert, is stripping gas, such as steam or Inertgs, z. B. nitrogen, combustion gas or Mixtures of such gases supplied to displace hydrogen and hydrocarbons, to strip off or desorb, which together with the catalyst in the pipe 23 downwards flow. This stripping gas flows through conduit 23 essentially upwards and in countercurrent to the catalyst flowing down.

The flow rate of the stripping gas can be equal or higher than the flow rate of the gases and vapors which make up the layer 18 flow upwards in the reaction zone.

Stripping gas and stripped components flow from the top of the pipe 23 in the fly ash phase 21 and mix there with the vapors the reaction products, which are stripped from the fluidized bed 18. The mixture is passed through one or more cyclone separators 27 in order to remove to deposit catalyst dust, which is in the fluidized bed 18 through the dip tube 28 to be led. The mix of. Reaction vapors and stripping gas are released from the Zykolon separator 27 withdrawn and through pipe 29 into the cooler 30 and from there into a suitable one Plant 31 for product extraction promoted. There is the desired liquid hydrocarbon product separated from water and the gaseous products, which contain about 50 to 70% hydrogen, while the rest consists mainly of hydrocarbons that are below normal Conditions. are gaseous. This gaseous product is normally in circulation '' returned to the reaction chamber, advantageously after heating to a reaction temperature, in order to carry out the endothermic running in this way a substantial part of the Hydroforming to supply crifordelichen heat.

The stripped catalyst flows out of Rolhr 23 into the transfer line 33 and through valve 34 in the upper part of the regenerator 35. According to the invention the used catalyst is treated in countercurrent with the regeneration gas. A simple way to perform this treatment is to have the Regenerator 35 has a plurality of horizontally arranged perforated plates 36, 37, 38 and 39 provides. Each of these perforated plates is equipped with a shaft to collect the solids to the next lower floor. Each shaft ends so far at the top above the ground that a certain minimum depth of the catalyst layer on each Floor is guaranteed.

The oxygen-containing regeneration gas is below the lowest Soil 39 is fed through pipeline 40. It flows n. A. cheill. at. the through all perforated plates upwards. When it has reached the top floor 36, sit its concentration of oxygen low and its concentration of Gesen which are on the lower floors due to the combustion of the carbonaceous deposits disfigure the catalytic converter, high. This is particularly desirable because of the transmission line 33 on the top floor 36 flowing catalyst substantial amounts of hydrogen and water vapor is formed by the combustion of this hydrogen. which a questionable deactivation of the catalyst, especially at high temperatures caused. Due to the low concentration of oxygen and the large volume of the combustion gases that reach the top floor 36, however, becomes the largest Part of the hydrogen burned off and / or stripped off that carried along with the catalyst or is bound to it by chemosorption at low temperature values, and the steam is immediately wiped off the catalyst.

The combustion gases flow above the top one.

Bottom 36 through a Zykolan separator to remove entrained Catalyst dust and are then discharged into the open air or can be used as Stripping gas is used, which is fed to the pipe 23 through pipe 26.

The catalyst, which still contains carbon dioxide, flows from the ground 36 to the lower Bpden 37, 38 and 39, where the carbon is released. There If only very little water vapor is present, the final stage of the regeneration can take place higher. Temperatures are operated so that a much larger amount of available Heat is transferred directly through the circulating catalyst into the reaction chamber can be. The flow velocity of the upflow through the regenerator The gas is adjusted in such a way that there is a strong swirling density on each perforated plate Catalyst layer is formed by a suspension of Katalystorflüsgaub in Regeneration gas is superimposed. For this purpose, the flow rate can be used of the regeneration gas in the regenerator, depending on the pressure, be 0.09 to 0.45 m / sec. With a regeneration of about 13.6 to 17 at, the flow velocity should be beispieslweise about 0.3 m / sec or less.

It is advisable to progress through the various regeneration zones operate at a higher temperature, e.g. the top regeneration zone should be 538 ° and the lowest between about 649 and 7600, while in denl correspondingly average temperatures prevail in the zones located there.

About the heat generated during the regeneration of the catalyst continue to booze and also the Temperature in the different To direct regeneration or barrier zones, can be found in the on each floor Fluidized bed pipes for the circulation of fresh feed and of.

Circulation gas can be provided to this before introduction into the reaction chamber 10 preheat.

If you are in the upper zone with a relatively low temperature operates, the stripping can be achieved with minimal combustion.

For example, the temperature can be 454 to 5380 and lower than that of the reaction chamber. In addition, one achieves an improvement in the Effectiveness of the fuel. As shown in the drawing, fresh Load material fed through pipe 41 and through one or more coils 42, 43 and 44 are passed, whereupon it is, after this preheating, by pipeline 45 leads into the main supply line 14, which opens into the reaction chamber. Cycle gas can be fed to coils 47, 48 and 49 through conduit 46 to it also preheat, whereupon it goes through pipe 50 into the supply line 17 flows. The regenerated catalyst flowing down from the lowest tray 39 flows through the shaft into the bottom part of the regenerator 35 and from there through the with a valve provided downpipe 51 in the pipe 17, in which it is from the Stream of the preheated recycle gas taken up and into the bottom part of the reaction chamber 10 is funded. As the catalyst, especially if it is molybdenum. contains while regeneration can be oxidized to a less active form, one can do it condition accordingly or to. reduce the catalytically more active form, while it flows through piping 17 or while it is in chamber 20 at the bottom of the Reaction chamber lingers.

Usually, a touch time of less than about .5 will be beneficial from about 1 to 3 seconds between the regenerated catalyst and the loop sufficient gas to restore the more active form of the catalyst.

For the implementation and upkeep of the desired working conditions are different, manually or automatically controlled devices, pumps, ovens or the like. Provided. A method of initiating and maintaining the process according to the invention is the following; The catalyst, e.g. B. a. those made from 10% molybdenum oxide on activated alumina or one of the other catalysts mentioned above from a storage container through pipe 17 by means of an air stream into the Reaction chamber promoted. It is removed from the reaction chamber through the outlet opening 24 withdrawn and conveyed into the regenerator 35. The valve in the downpipe 51 at the bottom of the regenerator is kept closed until the regenerator with catalyst is filled, with hot air being introduced through pipe 40 to the catalyst particles keep them in the vortex and heat them up. If reaction chamber and regenerator: -rator Are loaded with catalyst, the valve in the downpipe 51 can be opened and inert gas be passed through the reaction chamber to displace the air from it.

After the air has been completely displaced from the reaction chamber and the regenerator has reached a temperature of about 427 °, becomes oil or elin appropriate gaseous fuel burned in regenerator 35 to the catalyst continue to heat up Now a heating gas produced during the refining process is used to promote of the catalyst flowing out of the fall pipe 51 into the reaction chamber 10 and to the Cleaning of the pipelines for the cycle gas supplied. The catalyst circulation is continued until the reaction chamber has a temperature of about 454 ° has reached. Then the approach to the Bescb: idung (heavy fuel) begins.

As soon as enough carbon is deposited on the catalyst, the helmet burns down in the regenerator, nin to maintain the heat equilibrium: the introduction of oil or fuel into the regenerator is switched off Feed rate of heavy gasoline gradually increased and cii e plant a, uf Working pressure brought.

The 5 heavy fuel charge, advantageously an untreated heavy fuel, has a boiling range of 79 to about 232, advantageously 93 to 177 °. This load is preheated to around 260 to 316 °, for example through indirect heat exchange with product vapors in the heat exchanger 30, and then in that of the preheating. of Charging material serving pipe lye in the regenerator and / or in a separate one Oven, to 427 to 538, before partially about 510 °, further pickled. The loading goods should be preheated as high as possible, whereby a thermal degradation is d; urch. Limitation of the dwell time of the heated charge in conveying line 14 It is desirable to avoid the dwell time of the prebit load in this transmission line for about 1 so S second to eat the recycle gas should contain 50 to 70, advantageously 60 percent by volume hydrogen. At the beginning of Process may require outside hydrogen. feed to the Bring the hydrogen content of the cycle gas to this value. Dals circle 1 inflate is achieved by indirect heat exchange with the product vapors, e.g. B. in the heat exchanger 30, heated to around 3160, then in the pre-heating coils of the regenerator 35 and / or in a separate oven to about, 621 to 649, advantageously about '6410, to be further heated. The circulation speed of the cycle gas through d. ie reaction chamber is about. 18 to 71 m3 per 100 1 liquid load. The cycle gas is heated to the specified temperature and then in sufficient Amounts brought into circulation so that it is in contact with the regenerated catalyst the reaction chamber supplies sufficient heat to keep its operating temperature on the to maintain the desired height.

The temperature of the reaction chamber should be between 454 and 524, preferably at about 482 °, the reaction pressure between about .3.4 and 68, advantageous at about, 13.6 at leigenm. Temperatures above 4820 lead to increased carbon formation and to a lower 5 selectivity for gasoline fractions, while below 482 ° the reaction conditions are too mild and, as a result, excessively large reaction chambers will be required. The: lowering of the reaction pressure below 13.6 at leads to increased Carbon formation, which is abnormally large below about: 5 at. Above of 13.6 at, meanwhile, increases the selectivity of the catalyst for light products (C4) quickly.

The weight ratio of the catalyst to that in the reaction chamber imported oil or the circulation speed of the catalyst between Rescation chamber and regenerator in relation to the feed rate of the Oil is in between about 1 and 3. It has to be low enough to excessive carbon formation or degradation of the product by the Avoid oxygen that is fed back with the catalyst. The height The temperature of the catalyst allows it. large amounts of heat from the regulator in to transfer the reaction chamber.

The ratio of catalyst to oil can go as low as 0.5. At higher pressures, the catalyst-oil ratio can be increased. For example game, a ratio of 2 to 5 is recommended at a pressure of about 34 atmospheres. The throughput is given as parts by weight of charge / hour / part by weight of catalyst defined in the reaction chamber. The throughput in the reaction chamber depends on the age or degree of activity of the catalyst ah. The throughput of loading at one catalyst, which consists of molybdenum oxide on activated alumina, can depending on the catalyst activity, the desired octane number of the product and the properties of the charge from about 1.5 to about 0.15 part by weight / hour / part by weight be. The temperature in the regenerator should be between. around 5350 in the first regeneration zone up to 6490 or higher in the last regeneration zone.

In the description are various embodiments of the present. Invention explained. If necessary, within the scope of the invention, the person skilled in the art offer numerous deviations.

Claims (3)

PATENT CLAIMS: 1. Process for regenerating catalysts, those for the hydroforming of hydrocarbon fractions in the boiling range of heavy gasoline used in fluidized bed by. Removal of the spent catalyst from the fluidized bed of the reaction chamber, stripping entrained gases and treatment with oxygen-containing gases at a higher temperature, characterized in that in on. the stripped ta. lysator in and out of the upper part of a regenerator d through several consecutive regeneration zones lelit.et, through which a regeneration process is carried out in countercurrent to the catalyst with a flow velocity depending on the pressure, from 0.09 to 0.45 m / sec passes, so that in each regeneration zone A fluidized bed of the catalyst forms the regenerated catalyst from the last regeneration zone. and circulated back into the reaction zone. 2. The method according to claim 1, characterized in that the Operating temperatures in successive regeneration zones increase. 3. The method according to claim 1, characterized in that in the first regeneration zone. Hydrogen with a low oxygen and combustion gas rich Regeneration gas from the Katar lysator and the remaining on the catalyst carbon-containing deposits in the subsequent regeneration zones with a Regeneration gas burns off that is richer in oxygen and lower in combustion gas than the regeneration gas which is used in the first regeneration zone, the regeneration gas being preferred progress, becoming more oxygenated. Considered publications: German Patenstschriften Nr. 715 066, 736 528; French patent documents nos. 864 863, 941 334; cauadic U.S. Patent No. 481,326; U.S. Patent Nos. 2,456,148, 2,457,566, 2,477 019. Cited earlier rights: German Patent No. 885 697.