DE914131C - Contact furnace - Google Patents

Description

Contact furnace For the catalytic hydrogenation of carbons to hydrocarbons or hydrocarbons and oxygen-containing hydrocarbon compounds, in particular According to F i s c h e r - T r o p s c h, contact furnaces were used in which the Catalyst in tubes or in the annulus between concentric pairs of tubes was housed in thin layers of about 10 to 25 mm thick. The pipes were and were cooled with boiling pressure water or other boiling liquids fastened in tube sheets at the top and bottom. It has also been suggested that. Catalyst to arrange such tubes and introduce the coolant into the tubes. Both types of construction required a lot of material and construction costs. The contact furnaces with coolant pipes had the further disadvantage that the filling and discharging of the catalyst caused considerable difficulties.

The disadvantages of the known furnace are eliminated by the invention. The advantages of the invention are over. known ovens, especially in A much lower material cost and in the simpler one. and more convenient Design of the ovens.

According to the invention in contact furnaces in which the catalyst is arranged around cooling tubes, the cooling tubes to form adjacent units, in particular rows of tubes or annular or polygonal, z. B. six, seclçigen Units combined, and the pipes of each unit are above and below connected to a common manifold for each unit, especially in openings welded into these manifolds. Each. upper manifold is in turn at the top. through a conduit to a 'discharge pipe and each lower collecting pipe as well connected by a line to a supply pipe. Man can but also two or more headers in the same way with a common one Connect discharge pipe or supply pipe or a common discharge pipe and provide a common feed pipe for all headers.

In some cases it is advisable to have two or more connecting lines to be arranged from a collecting pipe to the supply or discharge pipe (s). Through the supply pipe or pipes, the coolant is transferred to the headers and over these are fed to the cooling tubes.

A mixture of water vapor and liquid escapes from the cooling tubes through the header pipes and the or the discharge pipe inl individually evaporator or Separator in which vapor and liquid separate. The separated liquid is used together with fresh coolant, e.g. B. Condensate when using, water vapor as coolant, fed back into the supply pipe.

Instead of boiling water you can also. other coolants used be e.g. B. Diphenyl, or coolants, such as hydrocarbon mixtures, the one have a larger boiling range and where there is a change in concentration due to the evaporation process occurs in such a way that the higher-boiling ones are in the lower part of the cooling tubes Enrich components of the mixture, so that a temperature gradient in the coolant column occurs in the cooling tubes. You can also let the boiling coolant through the cooling tubes keep in the circuit and a Pressure drop and thus a lowering of the boiling point of the coolant at Create a passage through the cooling tubes.

The invention has the. Advantage that the jacket of the contact furnace only is under the pressure of the synthesis gas, which in most cases is much lower is than the pressure of the boiling coolant. Only the cooling tube walls are subject to this higher pressure and the walls of the headers as well as the inlet and. Exempted discharges.

In this way, a significantly more favorable pressure load is achieved of the apparatus, since an overpressure within the contact furnace only arises in the pipes and furthermore, since these tubes are used with relatively small cross-sections can, so that you get by with correspondingly small wall thicknesses of the pipes. Further the advantage arises that the introduction and discharge of the contact is essential is made easier because the contact spaces are easily accessible from above and below. aside from that the compensation of the thermal expansion is essential in the contact furnace according to the invention cheaper than arranging the pipes in raw, rboden .. Also the monitoring of the Apparatus is made easier.

In particular, any The weld seam can be viewed from both sides. Will be after a long period of operation Pipes e.g. B. leaking due to corrosion, they can be replaced with little effort be there any! Tube unit light for sidh. taken out of the Ko, nF clock oven, can be repaired and reinstalled.

Further advantages of the invention reside therein. that the coolant content of the contact furnace is relatively small and the heating-up time of the furnace is correspondingly small is short and the vapor space load (evaporation rate) is kept low can. Finally, there are also the facilities for separating the coolant vapor from the cooling liquid and. easier for its removal from the contact furnace than with the known open.

The cooling tubes of each unit, which lie on the jacket of the contact furnace, E.g. in the case of continuous rows of tubes, the outer tubes of each row of tubes are retained advantageously a larger diameter than the other tubes. The The diameter of the tubes lying on the contact furnace jacket is chosen to be so large that these Pipes of the individual pipe units touch one another directly and lie against one another. This prevents the contact from making contact with the jacket of the contact furnace occurs. The space between the outer tubes and the jacket of the contact furnace becomes expediently sealed against the passage of gases, wa.s z. B. du.rch fill in of the room with fillers, putty, asbestos or the like. Can happen.

The evaporator to which the vapor mixed with liquid refrigerant of the coolant is supplied, is expediently designed as an annular space, e.g. a ring tube, surrounding the upper part of the contact furnace. The derivatives for the steam and the liquid is expediently a suitable piece from the mouth of the Feed pipe removed in the ring tube, so that as complete as possible in the ring tube Separation of the liquid from the vapor succeeds. The freshness is beneficial Coolant introduced into the ring tube.

This is achieved by raising it to the required inlet temperature heated, gets into the cooling tubes. It is recommended that the entry of the fresh To put the coolant at a point on the ring tube that is exposed to the outlet of the liquid Coolant has a sufficient distance from the ring pipe, so that a possible complete temperature equalization between the fresh coolant and that from the Coolant vapor separated coolant is achieved.

The drawing serves to further explain the invention.

Fig. I is a vertical section through the contact furnace, the perpendicular runs to the rows of coolant tubes; Fig. 2 is a section roof line a-b in Fig. I, Fig. 3 a section along line c-d in Fig. 2; in Fig. 4 is another Embodiment of the contact furnace shown according to the form of the invention.

1 is the jacket of the contact furnace, the top of the cover 2 and on his the lower contracted end has the cover 3. The cooling tubes 4 are in rows summarized and with their upper ends in manifolds 5 and with their lower end up welded into manifolds 6. From the upper headers 5 lead lines 8 to the common discharge pipe 9, which is in the annular Evaporator 14 opens. The lower headers 6 are through lines 11 with the Feed pipe I2 connected. The two outer tubes 7 of each row have one larger diameter than the other tubes, so that the outer tubes of the rows touch immediately.

In this way it is achieved that the in the spaces between the Contact introduced into the cooling tubes cannot reach the furnace casing, which is to be expected unexpected temperature differences and a stronger heat transfer the furnace mantle would lead. In addition, this version of the Rohrreihenl has the The advantage that the outer tubes are more stable in the rows. In particular, there is a risk that, due to thermal expansion, the individual tubes from their deviate from the vertical position, significantly reduced.

This can provide further protection against distortion of the pipes be that between the row of pipes, roughly in the middle of the pipe length or at another suitable places, spacers z. B. in the form of, for example, horizontal Rods are inserted.

A ring I3 is attached to the bottom of the contact furnace.

The outer tubes of the row of tubes are supported on this ring, so that whose weight is taken up by the ring I3. If necessary, can be in the middle of the furnace under the lower header pipes still z. 13. one or two beneficial centrally turning support ribs or the like 22 (FIG. 4) may be provided.

The appropriately multi-part is located under the header pipes 6 und.d foldable gas-permeable bottom I5, which carries the contact and through which the Lines II are passed through.

The execution pipe g opens into the evaporator 14, which is an annular pipe is formed and surrounds the contact furnace at the top. The ring tube is expediently made two or more curved or straight pieces mounted, which are convenient, e.g. B. by welding, are connected to one another. The evaporator becomes the steam discharged through the line '16, while the liquid coolant through the line 17 returns to the feed line I2.

Fresh coolant can be supplied to the annulus through line I8 will. It then comes together. with the liquid separated from the vapor from the annular space 14 also through the line I7 into the coolant supply I2. The lines 16 and I7 are z. B. offset by 1800 to the mouths the lines I2 and I8 arranged. The line 17 is advantageously not vertical from the ring pipe to the feed 12, but z. B. wound along a helical line educated.

One can 'also taper the upper part of the jacket I conically and place the evaporator 14 over the conically tapered part of the jacket.

This results in a space saving. In addition, the cover 2 at the top correspondingly smaller in diameter, which in the execution of the synthesis has constructive advantages under pressure.

The synthesis gas passes through. the nozzle 19 in the oven and is The bottom out of the furnace through the nozzle 20 is fed out. But it can also be done in reverse Flow direction. There are also other changes and configurations to the contact furnace possible, which are known per se in the case of carbon hydration. The gap 21 between the outer tubes of the rows of tubes and the jacket 1 is useful with suitable filling compounds or the like.

The contact furnace after flight. 4 is designed in a similar way, but in this contact furnace is the number of cooling tubes 4, which are combined into a unit are chosen smaller, namely the arrangement is made so that the cooling tubes are combined into a single unit on each side of the furnace. For every On the side of the contact furnace, a feed pipe 12 and a discharge pipe g are provided on each side. This results in a lower steam speed in the collecting and discharge pipes.

Example For the more or less extensive removal of carbon monoxide from town gas by catalytic hydrogenation of carbohydrates to obtain.

Hydrocarbons or the like are, for example, formed according to the invention Contact furnaces used, with a gas pressure of about 3 at and a coolant vapor pressure operated from about 40 at. Each contact furnace contains 10 cbm of contact, and boiling water is used as a coolant.

According to the invention, cooling tubes with 17 mm are used for this contact furnace clear width; and a wall thickness of 1.5 mm is used. The pipe length is about 5 m. The distance between two pipes from pipe center to pipe center is measured to be 30 mm, this applies both to the pipes in each individual row and to the distance the tubes of two adjacent rows from each other, so that ben, achbarter than the axes three Tubes, seen in a perpendicular section to the tube axes, in the tips of a simultaneous one Triangle with a side length of 30 mm. This results in a vertical distance from outside wall to outside wall of the cooling pipes of 10 mm.

The diameter of the header pipes is appropriately slightly smaller than that of the cooling tubes made to facilitate the filling and draining of the contact. If the outer diameter of the header pipes is chosen to be 18 mm, the result is. themselves between the collecting pipes, gaps of 8.5 mm wide, which are sufficient for the filling and to be able to remove the contact without difficulty.

The jacket of the contact furnace has a cylindrical shape, so that the rows of tubes from the center to the sides, decreasing numbers of tubes are obtained.

The middle row contains about sixty-seven Tube, the shortest twenty-four tubes if seventy-five rows of tubes are used reach. Line up the side of the two shortest tubes facing the contact jacket can with a wall, e.g. B. made of sheet metal, provided with the two outer tubes each row is connected. The space between the two walls and the jacket of the Kon.ta.ktofen is not filled with catalyst and against the passage of gases. closed.

The individual rows of pipes are completed separately and pressed off and placed one after the other in the contact furnace. After installing all rows of pipes the lines of the upper and lower header pipes with the Dampfabführuugsrohr bizw. welded to the cooling water supply pipe.

The invention is also applicable to contact furnaces other than circular cross-section, e.g. B. have a rectangular or polygonal cross-section.

Claims (8)

PATENT CLAIMS: I. Contact furnace for the catalytic hydrogenation of Carbon monoxide to hydrocarbons or hydrocarbons and sa, ucarbonhaltigen Hydrocarbon compounds in which the catalyst is dormant between cooling pipes is arranged, thereby. characterized that d.ie cooling pipes to adjacent Heating, in particular rows, rings or the like. Are summarized in that the upper and lower ends of the cooling tube units fixed in headers, e.g. B. are welded and that the upper headers, one essentially same or smaller diameter than the cooling tubes surrounded by the catalyst have, through pipes with a common or several discharge pipes for the vapors generated from the boiling coolant and the lower headers through Lines are connected to a common or multiple coolant supply lines. 2. Apparatus according to claim I, characterized in that the to the pipes lying on the jacket of the contact furnace are given such a large diameter that they touch each other and the touch of the contact with the furnace jacket impede. 3. Apparatus according to claim 2, characterized in that the space between the outer tubes and the furnace shell against the gas passage z. B. by Introducing fillers, putty or the like is complete. 4. Apparatus according to claim 1 to 3, characterized by a Gew Steam collector or separator or the like, which surrounds the upper part of the contact furnace and the mixture of liquids and steam that is created in the cooling tubes, is fed through the headers and one or more discharge pipes. 5. Device according to. Claim 4, characterized in that the Steam collector as a ring pipe or as a pipe closed all around with a polygonal Floor plan is formed, where the ring tube is composed of several pieces, z. B. can be welded together. 6. Apparatus according to claim I to 5, characterized in that the liquid coolant separated from the steam in the steam collector through the line I7 is fed back into the supply line (I2), the line (17) from the steam collector appropriately branches off at a point that is at a greater distance from the mouth of the feed for the coolant vapors in the separator. 7. Apparatus according to claim I to 6, characterized by a at Supply for fresh coolant into the steam collector (14), which is expediently at a distance from the mouth of the discharge line (17) for the liquid coolant from the vapor collector flows out. 8. Apparatus according to claim I to 7, characterized in that the cooling tube units with their outer tubes on a ring (I3) and optionally Support on ribs or the like.