DE1442704A1 - Heat-insulated reaction vessel - Google Patents

Description

PATENT LAWYERS

DR.-1NG. BY KREfSLER DR.-ING. SCHÖNWALD 1442704 DR.-ING. TH. MEYER DR. FUES

KDLN 1, DEICHMANNHAUS

P 14 42 70 »Λ _{8% 8 # 1968}

Sch-Eb / cg

The Gas Council, Murdoch House, 1 Grasvenor Place, London, S.W. 1, England.

Heat insulated reaction vessel.

The invention relates to a thermally insulated reaction vessel for carrying out reactions under excess pressure, consisting of an inner wall enveloping the reaction zone and a pressure-stable outer one arranged at a distance from it. wall, with heat insulating in the space between the inner and outer wall Material arranged and a limited connection path between the reaction zone and the pressure equalization Space is provided.

The previously known reaction vessels of this type must in principle Be constructed to be pressure-resistant, but can also be used to carry out reactions under normal pressure if necessary be used. A completely tight seal of the reaction zone with respect to the one with heat-insulating material filled annular space between the inner and outer wall is generally not possible, especially if necessary work is carried out under high pressures in the interior, and it is

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As is well known, it is also desirable that, for safety reasons, the outer wall of such a reaction vessel should be constructed to be pressure-resistant because otherwise a reliable control of a pressure-tight inner wall is practically impossible. It is known to have a tubular pressure vessel with sufficient more stable outer wall and one comparatively less solid inner wall still to be provided with a partition and the heat-insulating material only in the annular space between Fill in the intermediate wall and the outer wall, thereby equalizing pressure between the inner wall and the free one To reach the annular space opposite the partition wall. Such an unfilled annular space naturally contributes to thermal insulation nothing, especially since both the inner wall at its upper end section and a large part of the intermediate wall must be perforated in order to create the desired pressure equalization, namely the inner wall when it occurs to protect rapid pressure changes from mechanical destruction.

Another construction is also known, which is hermetically sealed with one or more partition walls The purpose of rooms that are then to be evacuated to the To keep heat transfer through conduction and convection as small as possible. This construction is natural extremely expensive if you want to create a perfect vacuum that also has a sufficient service life Has. This construction has the disadvantage that, of course, the inner wall must necessarily be constructed to be pressure-resistant, "even if the operating pressures that occur should face a vacuum. The known construction also has the disadvantage that it is completely pore-tight Materials required, which "at least - when using metals, especially when using a hydrogen-containing High pressure and high temperature atmosphere is very difficult, so only with sufficiently strong

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Metal walls that do not have a microporous structure can be achieved with correspondingly high effort, because otherwise hot oxygen diffuses and destroys the vacuum. In addition, this complex method of construction has the considerable disadvantage that the thermal radiation, which increases with the fourth power of the absolute temperature value according to the radiation law, is not prevented at all in such a gap and is therefore of considerable importance, especially at high working temperatures.

To avoid all these disadvantages and a heat insulating one To create reaction vessel, its heat-insulating filling material, in contrast to the known construction without an expensive vacuum and, in contrast to the other already known construction, with an unfilled one The intermediate layer can usefully fill the entire space between the inner wall and the outer wall The present invention is based on a completely different object, namely the proven type of such a filling made of heat-insulating To increase the effectiveness of the material and thus significantly with the same thickness and the same internal temperatures to achieve steeper thermal gradients compared to the outside space.

As is known, the type and also the grain size of the insulating powder can be optimally used to solve the problem measured.

However, this measure results in only a slight improvement. You can also make sure that the filling in question has as few internal cavities or cracks as possible, so that the heat transfer by convection is as small as possible is held. However, this measure is extremely difficult to implement, because with a pourable Material-filled cavities have completely independent of the

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Grain size is known to be the proportion of cavities determined by the fill factor, which in the case of spherical granules keeps almost JO% of the space free from insulating compound and still makes up a considerable proportion of the space even in the case of irregular granules with a scattered fracture.

It is therefore known to produce intermediate layers that are as dense as possible by producing masonry, but it does exist in these cases the risk of cracks occurring as a result of changes in temperature and pressure, and consequently a gas circulation occurs, which in any case always strives, in the vicinity of the hot inner wall an upwardly directed one Convection and in the outlying districts to cause a downward convection, so that more or less large gas circulations interfere with the desired thermal insulation.

To solve the problem, the invention is based on the idea of suppressing the influence of these convection currents. The high specific resistances of eligible Isoliermateriales suppress virtually the heat transfer by conduction and from the gle cozy reason is the absorption of heat radiation definitely big enough, as opposed to the previously mentioned vacuum design and also in contrast to the aforementioned design with a completely unfilled interspace, which both transmits heat radiation unhindered, and also practically represents full convection due to the perforations provided for pressure equalization and preferably sufficiently large, namely the state in which the unfilled interspace has practically no noticeably lower temperature due to the continuous gas exchange , as the inner reaction space itself. Therefore, the invention aims at complete elimination of the thermal radiation and with negligibly small heat conduction, an effective

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same suppression of convection and thus the ideal case of thermal insulation between the interior of the reaction vessel and the outside temperature.

To solve this problem, experts have already proposed dividing the interior into short sections subdivide in order to thereby ascend in the longitudinal direction of the reaction vessel on the inside and in the outer areas to shorten flow circuits directed downwards. Naturally, this measure involves considerable manufacturing costs, in order to arrange ring-shaped and tight partitions between thin pipe spacings. In addition, with this effort Reach only a little, because apparently instead of the suppressed Convection circuits now have a number of correspondingly smaller circuits over the same total length distributed occurs. Taking into account the fact that in any case for each individual sub-cycle the full temperature difference is retained between the inner wall and the Außenbereiohen of the reaction vessel, leads to the Considering that all these small circuits are connected in parallel to one another when considering the direction of heat propagation perpendicular to the pipe walls as the flow direction. From this thought an analogy to electrical circuit technology a surprisingly effective solution found the task at hand, which can also be realized in practice with comparatively little cost; characterized in that, according to the invention, the space by one or more partition walls, which extend through the space in the longitudinal direction- ' device extend, is divided and the partition wall or the partition walls at a distance from the inner and outer wall and any

adjacent partition walls is or are arranged. The found In contrast to the suggestion mentioned, the solution is a series circuit against the heat flow direction. tion of self-contained spaces, in which each j individual of these annular spaces only a fraction of the heat potential β between the inner and outer radius. the

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The surprising effect of this "parallel connection" apparently corresponds to the arithmetical result that one in known Way, with a series connection of electrical capacitors, their total capacitance is only a fraction of the individual capacitance represents, while this in a parallel connection is multiplied accordingly.

Practical embodiments of the reaction vessel according to the invention are possible in numerous variants and the proposed partition walls basically only need to be tubular, which considerably simplifies the method of manufacture. This gives ring-shaped sub-spaces which are to be arranged concentrically at a distance from the inner and outer walls or further intermediate walls and which by no means only have to be partitions in the narrower sense. They allow rather in development of the E _r invention both a desired pressure balance, and in addition, the introduction of gases that transmit comparatively less heat than, for example, hydrogen in a pressurized atmosphere in the interior of the reaction vessel, the supply and discharge lines in cylindrical configuration, preferably in the Arranged end walls and, if necessary, provided either on opposite end walls or also on the same end wall if the addition of the reaction components and the removal of the reaction products are to take place at the same end of the reaction zone.

If the reaction vessel is to be used, for example, to carry out reactions under excess pressure, the Pressure equalization between the reaction zone and the heat insulating space between the inner and outer walls can be achieved, by forming or arranging the inner wall and each partition so that there is limited communication between the reaction zone and all isolation rooms are available if they are filled with heat-insulating material.

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For this purpose, a limited connection path can be provided, which crosses all the annular spaces with their width the reaction zone connects. This connection path can be outside the area covered by the heat-insulating Material is ingested. For example, reaction vessels of the type described have tubular ones Inner and outer walls and tubular partitions allow the inner wall and each partition to extend from the inside one end wall and stop just before the inside of the other end wall. That way will a limited path of communication across the open ends of the reaction zone and any annulus outside of the heat insulating one Material formed in the annulus. However, it is also possible that the limited connection path through the heat-insulating material runs. For example, the inner wall and the partition walls can be from the inside of the one end wall extending to the inside of the other end wall and bores in the inner wall and the partition walls be provided to form a limited connection path from the reaction zone radially across all annular spaces runs through the heat-insulating material.

A limited connection path can also be provided, which connects all the annular spaces one behind the other over their length with the Reaction zone connects. In this case, the connecting path runs from the reaction zone into one end of the annular space next to the inner wall, then from the opposite end of this annulus into the adjacent end of the next annulus and in the same way from the opposite end of the latter annulus to the adjacent end of one any further annulus. The connection path thus runs through the heat-insulating material in each annulus. For example, in a reaction vessel with a tubular inner and outer wall and tubular partition walls, the arrangement be taken so that the inner wall from the inner

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seldom the one front wall runs out and just before the inside the other end wall ends, whereby a narrowed opening leading to the reaction zone is formed, the tubular Partition next to the inner wall at one of its ends, the connection through this opening to the adjacent end of the next Annular space blocked and at the other end a narrowed passage between the adjacent ends of the separated from it Annular spaces and each subsequent partition alternately at their opposite ends a limited communication path leaves between the adjacent ends of the annular spaces separated from them.

In each annulus there is a certain heat transfer as a result of conduction and / or radiation within the gas in the annulus instead, the rate of heat transfer partly depending on the gas composition. With certain gases, in particular with hydrogen (the high thermal conductivity on «-

at
; has) and mainly / consisting of hydrogen gas

: can mix, the heat transfer within each annulus worsen the insulating effect somewhat. In order to prevent these gases from leaving the reaction zone through the connection paths mentioned penetrate into the heat insulation room, one can Provide devices in the thermal insulation room through which one

Gas with relatively poor heat transfer, e.g. coal ; Dioxide flow through the room into the reaction zone * can.

The outer wall of the reaction vessel is generally made of metal, for example steel, especially if the vessel is for use is constructed at overpressure. The inner wall can also be made of metal, e.g. steel, but it can also be made of non-metallic material, e.g. a refractory lining, be made, which is provided with a refractory coating, for example by spraying a refractory Mass (e.g. of the product with the trade name "Gunite")

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is brought. The partition walls can be made of metal, e.g. mild steel or heat-resistant steel, or of a non-metallic, gas-impermeable material, e.g. gas-impermeable aluminum oxide.

For thermal insulation, it is preferable to use a free-flowing, Finely divided material, e.g. powdery alumina, but a coherent material, e.g. heat-insulating material, is also used Masonry, in question.

Reaction vessels according to the invention can be used to carry out reactions under normal pressure or overpressure and at high Temperatures - or also relatively low temperatures be designed. In the latter case, it is not essential that the materials from which the walls, partitions and the consist of heat-insulating material, are resistant to high temperatures. For operation at overpressure, the The outer walls of the vessel in contact with the atmosphere must of course be designed to withstand the pressure applied resist. At the same time, limited connecting paths are provided between the reaction zone and the heat insulating space.

The reaction vessels can be used to carry out reactions between gases and / or vapors. Also solids may be present and, if appropriate, participate in the reaction. These solids are preferred held in the form of a fluidized bed in the reaction zone. In this case, the inner wall is preferably made of metal.

A reaction vessel designed according to the invention can be used to carry out the subject matter of the German patent .......... (patent application G 27 250 IVd / 26a) by the applicant forming process for the vapor phase hydrogenation of hydrocarbon Distillate oils can be used. Intended for

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Implementation of this process is according to this patent a Reaction vessel with a tubular inner wall enclosing the reaction zone and one at a distance from the inner wall arranged outer wall in contact with the atmosphere, thermal insulation material in the space between the Inner and outer wall as well as end walls that close the ends of the outer wall. There is a hollow cylinder in the reaction zone provided, which is shorter than the reaction zone and this into an inner region of cylindrical cross-section and divides an outer region of annular cross-section. The two areas are over the ends of the hollow cylinder connected to each other. The reaction participants are introduced through an opening in one of the end walls, the reactants and reaction products pass through the cylindrical and the annular area of the Reaction zone around, and the reaction zone is, for example, through an outlet nozzle in the one with the inlet opening provided front wall removed. If a reaction vessel according to the invention is used for this process, subdivided the heat insulating space between the inner and outer walls of a reaction vessel designed according to the patent mentioned with partition walls in several annular spaces, which, as described above, accommodate a heat insulating material.

Reaction vessels of the construction according to the invention are shown as examples in the figures, in which the same reference numerals denote the same parts. In each case, longitudinal sections of the reaction vessels are shown, the embodiments according to Fig. 2, j5 and 4 with means for preventing the penetration of gases that are relatively high Heat transfer, would lead in the heat insulation room, provided are. -

That in Pig. 1 shown reaction vessel consists of one cylindrical outer wall 1, which against overpressures \ within the

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Is resistant vessel, a reaction zone 3 enclosing cylindrical inner wall 2, which is coaxially disposed in the outer wall at a distance therefrom, and two end walls 4 and 5, is used, each with an aperture or as an entry as the exit from the reaction zone. The inner wall 2 stops at the top just before the underside of the end wall 4, so that the space between the outer and inner walls is in communication with the reaction zone. The annular space is divided into three annular spaces 6, 7 and 8 by two cylindrical partition walls 9 and 10, which are arranged coaxially to the inner and outer walls of the reaction vessel. The partitions 9 and 10 stop at the top just below the underside of the end wall 4, so that the pressure in each annular space is the same as in the reaction zone. Each annulus is filled with a free-flowing, finely divided, heat-insulating material, such as powdered alumina. The partitions can be made of metal, for example mild steel or heat-resistant steel. Instead of two partitions, one can use a partition that forms two annular spaces or, for example, three partition walls that form four annular spaces.

The reaction vessel shown in Fig. 2 has the same construction as that shown in Fig. 1 with the exception that an annular tube 11, 12 and 13 is provided at the lower end of each annular space 6, 7 and 8. Each of these tubes is provided with bores (not shown) through which a gas, which is supplied to the tubes through inlet lines 14, 15 and 14, can be introduced into the annular spaces. For example, a gas with a relatively high heat transfer, such as hydrogen, is prevented from penetrating from the reaction zone 3 into the finely divided material in the annular spaces by introducing a gas with a relatively poor heat transfer, such as carbon dioxide, from the respective annular tube. This gas flows through the finely divided material and into the reaction zone at the opposite end of the annular spaces

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Pig. 3 shows the same reaction vessel as FIG. 1 with the exception, that the partition 10 below just above the Top of the end wall 5 ceases and is provided at the upper end with a flange 19, which is at a short distance from Partition 9 is guided to the inside of the outer wall 1., and that a pierced annular pipe 17 with inlet pipe 18 is provided at the lower end of the annular space β. Here is a Gas with relatively poor heat transfer from the tube 17 successively through the finely divided material in the annular spaces 6, 7 and 8 and passed from there into the reaction zone.

In Fig. 4, a similar reaction vessel is shown with a single partition wall 20, which is inclined at the upper end Flange 21 is provided, which is the. Upper · End. Of the annular space between the partition 20 and the outer wall 1, and which ends at the bottom just above the top of the end wall 5.

one from a pierced ring tube 22, the with / insertion tube 23 and at the upper end of the annular space between the outer wall 1 and the intermediate wall is arranged, a gas of relatively low thermal conductivity is through downwards the finely divided material in the outer annular space, around the lower end of the partition wall 20, up through the finely divided material passed in the annular space between the partition 20 and the inner wall 2 and into the reaction zone.

It can be seen that in all of the reaction vessels shown there is a limited connection path between all of the annular spaces and the reaction zone is present, and that the partition walls allow gas flow through the insulating material from an annulus to the prevent others along the entire length of the partitions. The slight flow of gas above and below some of the partitions other partitions is not so strong that it substantially improves the thermal insulation provided by the partitions affect.

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Claims (1)

Heat-insulated reaction vessel for carrying out reactions under excess pressure, consisting of a reaction zone enveloping inner wall and a pressure-stable outer wall arranged at a distance from it, whereby in the room heat-insulating material between the inner and outer walls arranged and a limited connection path between the reaction zone and the intermediate space for pressure equalization is provided, characterized in that the gap by one or more in the longitudinal direction of the Interspace extending, essentially gas-impermeable partition walls (9 * 10) 'in a plurality of with heat-insulating Material filled chambers is divided, the partition or partition walls at a distance from the inner and outer wall and any adjacent partition walls are arranged. 2. Reaction vessel according to claim 1, characterized in that the limited connection path transversely all spaces connects to its width with the reaction zone. J. Reaction vessel according to claim 2, characterized in that the limited connection path is arranged outside of the heat-insulating material ί located in the interstices. 4. Reaction vessel according to claim 2, characterized in that that the limited connection path is provided within the heat-insulating filling of the spaces. 5. Reaction vessel according to claim 1, characterized in that the limited connection path the spaces one behind the other ** connects to the reaction zone over its length. 809809/1012, ' .- * ■ - ^ 6AOQRfGINAL ο. Reaction vessel according to one of Claims 1 to 5 * thereby characterized in that a gas inlet (l4,15jl6) is provided to the intermediate space provided with insulated material is. 7. Reaction vessel according to one of claims 1 to 6, characterized in that the intermediate spaces are designed as annular spaces are and at the ends of the outer walls of the vessel end walls (4,5) are arranged. 8. Reaction vessel according to claim J, characterized in that one end wall (5) is provided with an inlet connection and the other end wall (4) with an outlet connection for the reaction zone (j5). 9. Reaction vessel according to claim J _3, characterized in that the inlet and outlet are arranged in the same end wall. 10. Reaction vessel according to claim 7, 8 or 9, characterized in that the annular partition wall rests against one end wall (5) and ends at the other end wall (4) at a distance therefrom. 11. Reaction vessel according to claim 7 * 8 and 9 * characterized in that that the partitions alternate on one ■ Make contact with the front wall and end with it and end at a distance from the other front wall. BATH 80 980 9/10 12