WO2000061704A1

WO2000061704A1 - Fluid catalytic cracking facility and flap valve for said facility

Info

Publication number: WO2000061704A1
Application number: PCT/EP2000/002821
Authority: WO
Inventors: Günter Nägler; Peter Viess; Peter Weidgang; Hans-Jürgen HILGER
Original assignee: Zimmermann & Jansen Gmbh
Priority date: 1999-04-08
Filing date: 2000-03-30
Publication date: 2000-10-19
Also published as: AU3815900A; DE19915889A1

Abstract

The invention relates to a fluid catalytic cracking facility having at least one line with a check valve, which is cross-flown by a bulk catalytic material, wherein said check valve is a flap valve (700) having at least one flap (702a, 702b) that can rotate around an axis of rotation (701a, 701b) located laterally relative to a through hole (605) in a cross-sectional plane of the line (600).

Description

Fluid catalytic cracking system and flap valve for such

Description

The invention relates to a fluid catalytic cracking system, also known as an FCC (FLUID-CATALYTIC-CRACKING) system, according to the preamble of claim 1 and a flap valve for use in such a system.

In fluid catalytic cracking plants of the type referred to here, a catalyst in the form of microspheres (with an average particle size of approx. 50-70 μm) is used which, when swirled with hydrocarbon vapors or air, changes into a liquid-like state in which it is in Pipelines are transported in the system.

In known FCC plants, the catalyst is continuously regenerated in a fluidized bed or fluidized bed process.

In the known flexicracking process from Esso Research and Engineering Co., the reactor and a regenerator are arranged at the same height and connected to one another by U-shaped catalyst tubes. The preheated material to be cracked is fed into a reactor riser of the reactor, where evaporation and cracking of the hydrocarbon components begins immediately. The required heat energy is supplied by the hot catalyst mass. The flow of hydrocarbon vapors loosens the catalyst mass and leads to the formation of a fluidized bed in the reactor. Since the density of the catalyst mass in the downpipe of the regenerator is greater, the catalyst flows continuously from there.

The cracked products leave the reactor via cyclones that retain entrained catalyst dust. The carbonized catalyst moves down the wall of the reactor and collects at the bottom of the reactor, where adhering hydrocarbon residues are stripped off with water vapor. Transport to the

The regenerator is made by blowing so-called "auxiliary air" into the riser. The "main air" required to largely burn off the coke and to form the fluidized bed is blown in at the bottom of the regenerator. The reactor temperatures are generally 500-525 ° C .; be in the regenerator

Temperatures of 580 - 610 ° C reached. There is an excess pressure of about 0.7 bar in the reactor. The regenerator pressure is approximately 1.0 bar. In addition to gas oil, heavy vacuum distillates and deasphalted residues can also be considered as starting materials.

In another embodiment of an FCC system, the reactor is arranged above the regenerator.

The arrangement of the reactor above the regenerator results in higher differential pressures between the regenerator and the reactor (1-2 bar), so that control fittings, in particular mechanical shut-off valves, have to be installed in the catalyst tubes. The catalyst riser tube is relatively long, so that it can be used to a much greater extent than in the Esso process for the cracking reaction. According to the prior art, one- or two-plate gate valves are used as shut-off devices in the lines through which the fluidic catalyst mass flows, which are known to have one or two in corresponding guides perpendicular to

Have longitudinal axis of the corresponding line and sliders displaceable to the direction of flow of the fluid. These slides require a relatively large amount of space, since the major part of the valve volume lies outside the line to be shut off, and have proven to be relatively susceptible to faults in the area in question here. In particular, malfunctions frequently occur due to caking of the flow medium on the guides and as a result of the relatively high abrasive wear on the inner parts. In addition, the known slide valves in one version are those that exist in cracking plants

The requirements are sufficient, complex and costly components.

The invention is therefore based on the object of specifying a simplified, more cost-effective and more reliable installation of the generic type, and in particular a corresponding shut-off element.

This object is achieved in terms of its system aspect by a fluid catalytic cracking system according to claim 1 and in terms of the shut-off element aspect by a flap valve according to claim 7.

The invention includes the basic idea that the shut-off elements provided in lines of a fluid catalytic cracking system through which fluidic catalyst mass flows are at least partially designed as flap valves. This gives you a number of advantages:

- The size and the overall manufacturing expenditure associated with the execution (including drive and

Insertion into the piping system) and consequently the associated costs are significantly reduced.

- The relative simplicity of the structure results in significantly reduced preparation and manufacturing times. - The principle-related reduction in abrasive wear and the potential for disruption caused by the baking of the fluidic catalyst mass results in a significant reduction in susceptibility to malfunction and thus in maintenance and repair costs. - With a suitable design of the flap valve, there are positive influences on the flow and thus potential for increasing the effectiveness of the entire system.

- Warehousing for both manufacture and maintenance is simplified, thereby reducing the time periods for. a restoration of the system readiness in the event of a malfunction.

The advantages mentioned come to the fore in an FCC system of the type mentioned in claim 2 if a flap valve is arranged there in the downpipe and / or in the bulk material line between the reactor and the regenerator, because the mechano-thermal stress of the Shut-off member and thus the risk of malfunctions occurring is particularly great.

However, the advantages mentioned also justify the expediency of providing a flap valve in the regenerator associated with the fluidic catalyst mass. flowed lines, especially the catalyst return line and / or the catalyst discharge line.

But it is also a version of the system with flap valves on other actuators. possible in an advantageous manner, such as in an exhaust pipe.

In order to further reduce the susceptibility to malfunction, which is already significantly reduced, there is an appropriate further training

Flap valves Connection piece for supplying a cleaning fluid, in particular a pressurized gas (N ₂ oa) and / or for introducing emergency actuating means - such as manual actuating rods - which are directed, in particular, from the rear onto the flap or flaps.

The proposed provision of flap valves instead of locking slide arrangements basically allows (with the exception of lines of very small diameter) in a cost-saving manner to dispense with separate housings and the direct insertion into the line course. From a different point of view, however, an alternative embodiment as a separate assembly is also to be regarded as advantageous, since it facilitates prefabrication, maintenance and, if necessary, replacement of the shut-off element.

This applies to both cold-wall and hot-wall arrangements, with the former having to carry out the lining in a suitable manner in the area of use. Within the framework of valid standards for such systems, the cold wall flap valve is attached, in particular, under the outlet of a brick funnel and that of the hot wall flap valve under a metal plate. A flap valve which is suitable for use in the fluid catalytic cracking system is distinguished by the fact that it has two flaps whose extension planes in the closed position enclose an acute angle (preferably between 30 and 60 °, in particular 45 °) with the cross-sectional plane of the line. Preferred here is the design with two flaps which are of different sizes, but which are arranged essentially symmetrically with respect to a central plane of the line, one of which flaps openly against the end face of the other in the closed state.

Since the flaps can be exposed to considerable pressure and alternating loads, reinforcement on the back by reinforcing ribs (in particular also running on the side edges) is advisable for appropriate locations. Wear-reducing armouring can be provided on at least part of the edge areas on the flap or flaps if the flap valve is used at particularly exposed points in the system. In a preferred embodiment of the

Valve surfaces are essentially completely covered with Hexmesh and a corresponding stamping out.

The flap valves are actuated by electrohydraulic drives, which are known per se and can be implemented in a simple manner and in a smaller design for flap valves than for gate valve arrangements.

The basic shape of the flap valve can be both square and rectangular or circular, as far as the opening cross section is concerned, with the square or rectangular Rounded corner areas have a wear-reducing and thus disturbance-reducing effect.

So that the full opening cross-section of the valve seat can be flowed through in the open state, the pivoting mounting of the flap advantageously takes place so far outwards relative to the edges of the opening area that the flap distance in the open position is somewhat larger than the width of the opening area of the valve seat or an upstream orifice.

The expediency and advantages of the invention result from the subclaims and the following explanation of exemplary embodiments with reference to the figures.

Of these show:

1 is a schematic diagram of an FCC system according to a first embodiment,

Fig. 2 is a diagram of an FCC system opposite one

1 modified embodiment, FIGS. 3a-3c different views of an embodiment of a cold wall flap valve according to an embodiment of the invention,

4a-4c different views of a flap valve in a hot wall embodiment.

1 comprises a line 10 through which the starting material, in particular long-chain hydrocarbons CnHm, are fed in to carry out a catalytic cracking. The supply takes place with the support of feed pumps 11 arranged in parallel, each of which is a Wedge-in-wedge slide 5 are upstream and downstream. The feed of the starting material takes place in a feed area 13, to which, on the one hand, a riser 14 is connected and, on the other hand, a down pipe 15 opens. The upper end of the riser 14 opens into a reactor 16, which is arranged above a regenerator 17 in the embodiment shown. The downpipe 15 is connected to a collecting space 18 of the regenerator 17 arranged on the bottom, the collecting space 18 for receiving a bulk material-like one

Catalyst mass is used. A compressed air line 19 also opens into this collecting space, through which compressed air is blown into the collecting space 18 with the formation of a catalyst fluidized bed. Catalyst mass can be removed from the collecting space 18 via a line 20. This is held in an intermediate container 12 until further use, a shut-off valve 6 being arranged in front of and behind the intermediate container 12.

The reactor 16 also has a catalyst collecting space 21 at the bottom. The collecting spaces 18 and 21 of regenerator 17 and reactor 16 are connected to one another via a bulk material line 22.

At the top of the reactor 16, a line 31 connects to a fractionation column 32, in which the hydrocarbons split up in the reactor are separated into gas and gasoline, gas oil and relatively long-chain bottom products. The long-chain bottom products are fed back to the cracking process via a line 9, namely by introduction into the feed line 10.

The catalyst mass used for cracking is regenerated in the regenerator 17. In particular, the Regenera

, CORRECTED SHEET (RULE 91) ISA / EP Tor frees the catalyst particles of coke, by burning off the coke layer formed on the surface of the catalyst particles. The air required to burn off the coke is blown in at the bottom of the regenerator, specifically through the compressed air line 19 already mentioned.

To prevent overheating, water or steam can be fed into the upper part of the regenerator for cooling. The temperature in the regenerator can rise to about 750 ° C.

The flue gases 23 can be passed on their way to the chimney 25 via an expansion turbine 24 and / or through a boiler 26, the expansion turbine 24 and the

Boiler 26 are arranged in a bypass line 27 and 28, respectively. Both the expansion turbine 24 and the boiler 26 are each a glasses slide 3 upstream and downstream. Furthermore, flap valves 4 are arranged for the desired diversion of the flue gases both in the flue gas line 23 and in the bypass lines 27, 28, in accordance with the arrangement in FIG. 7. Immediately behind the regenerator there is also a gate valve in the flue gas line 23 2, with which the flue gas line 23 can be opened or closed off to a greater or lesser extent.

Both in the downpipe 15 and in the bulk material line 22 there is a double flap valve 29 or 30 of the construction described below with electrohydraulic actuation. The actuation or control takes place according to the premises known per se for such a system. The cracking process within the riser 14 and the reactor 16 is known, with hydrocarbons introduced into the region 13 taking the catalyst particles supplied through the down pipe 15 up through the riser 14 to the reactor 16. The thermal energy required for the evaporation and cracking of the hydrocarbon components is supplied by the hot catalyst mass, which can have a temperature of up to 750 ° C. at the outlet of the regenerator 17 or regenerator collecting chamber 18. Since the starting material to be cracked is introduced in the region 13 at a temperature of only about 200 to 250 ° C., when it comes into contact with the hot catalyst mass, hydrocarbon vapors arise, ie gas bubbles, at least some of which rise upwards in the downpipe 15. However, the gas bubbles are prevented by valve 30 from reaching the collecting chamber 18 of the regenerator 17. The hydrocarbon vapors generated in area 13 are not lost to the cracking process in this way.

FIG. 2 shows a further, slightly modified cracking system 100 in terms of its overall structure. With regard to the broad similarities with the system described above and the basic familiarity with this modified version as well, essential elements are identified by the labeling in the figure, and in the following only pointed out some essential aspects in connection with the explanation of the invention. The essential components in this case have reference numerals chosen based on FIG. 1, so that in this regard too, reference can essentially be made to the above description.

A first peculiarity here is that in the catalyst discharge line 120 coming from the regenerator 117 a - in addition to the flap valves 129 and 130 in the downpipe 115 or the bulk material line 122 - another flap valve 131 is provided. Furthermore, between the regenerator 117 and the associated collecting space 118, a catalyst return line 132 is implemented, in which a flap valve 133 is also arranged. A further flap valve 134 is provided in the flue gas line (somewhat modified in its course and the associated components and therefore designated 123 ′ in the first section and 123 ″ in a second section) above an outflow or expansion chamber 135.

Numbers 2-5, 7 and 8 (which sometimes appear several times) indicate a number of valves in the system of different but known design, namely numbers 2 and 4 a shut-off or isolation valve (isolation valve), numbers 3 and 3a an exhaust gas multi-way valve (butterfly valve), numbers 5 and 7 each a shut-off valve (shut-off valve) and number 8 a special check valve (special check valve).

The effects and advantages of using flap valves

129, 130, 131, 133 and 134 in Appendix 100 result from the general statements above and are therefore not repeated here.

3a-3d show a cold wall line section 600 of a fluid catalytic cracking system with a built-in flap valve 700 in the closed position.

3a shows a longitudinal section in a sectional plane perpendicular to the plane of symmetry of the flap valve, FIG. 3b shows a longitudinal section in the plane of symmetry S from FIG. 3a and FIG. 3c shows a cross section in a plane below the flap valve with a view of the latter from below. The line 600 has a steel wall 601 with a refractory acidification 602, which is tapered towards the pipe wall 601 in the area provided for the installation of the flap valve 700. The conical bevel corresponds to the shape of a

Funnel 603, on the inner wall of a Hexmesh lining

604 is missed. At the outlet of the funnel 603, an approximately rectangular opening 605 with rounded corner areas is provided with the Hexmesh® 604 in the center of the lining. On the underside of the

Opening s nd in a wide undercut 606 of the

Brick lining 602 is attached to two supporting and rotating axes 701a, 701b, two pivoting flaps 702a, 702b which are designed and held almost symmetrically to a central plane S of line 600. The flaps are designed and mounted in such a way that in the closed state shown in FIG. 3a their extension plane is inclined at 45 ° to the cross-sectional plane of the line 600. In the open position indicated in dashed lines in FIG. 3a, the flaps 702a, 702b hang parallel to the plane of symmetry S and thus to the main flow direction in the pipe cross section, the

The distance between their extension planes here is slightly larger than the clear width of the opening 605. The surfaces of the

Flaps 702a, 702b each have a Hexmesh ® covering 703a, 703b with corresponding stamping. The flap 702b is slightly larger than the flap 702a and hits the front edge (end face) of the flap when it is closed.

3b and 3c it can be seen that the lining 602 on the front and rear wall in the region of the attachment of the flap valve 700 also has a hex mesh lining 606.

An electro-hydraulic actuation device 704 for the flaps 702a, 702b is also shown in outline in these figures, which acts on the axes of rotation 701a, 701b. It can also be seen that on the side of the tube section on which the electro-hydraulic actuating device 704 is placed, the tube wall 601 and the lining 602 are perforated with a stepped rectangular opening 607, which is covered with a thick steel plate 705 with a correspondingly stepped lining 706 is closed. Towards the interior of the tube, this is covered with a separate section 606a of the already mentioned Hexmesh "lining 606. Through the steel plate 705 and the associated lining 706, the supporting and rotating axes 701a, 701b are guided in corresponding bores, and this implementation has its counterpart in corresponding bores on the opposite side of the tube wall 601 and lining 602. Here, holding flanges 707a, 707b are placed on the tube wall 601, in which the support and rotation axes 701a, 701b are rotatably supported and axes of rotation 701a, 701b are additionally guided in guide sleeves 708a, 708b. The opening 607 is used for the insertion and, if appropriate, also the maintenance or disassembly of the flap valve 700 as a coherent assembly.

In FIGS. 4a-4c, a flap valve 900 in a hot-wall design in a hot-wall pipeline 800 is shown - in a manner analogous to FIGS. 3a - 3c in two longitudinal sectional representations and one cross-sectional representation. The arrangement is largely similar to the first embodiment described above, so that parts which correspond to one another functionally are also designated by corresponding reference numerals and will not be described again in more detail below. The steel pipe wall 801 of the line 800 is lined with Hexmesh 802 with the appropriate stamping out without a fire-resistant brick lining. A steel plate 804, which extends in the cross-sectional plane of the line and has a central opening 805 which (as in the first embodiment) is essentially rectangular and has rounded corner regions, is inserted into the line 800, via ring welds 803 to the wall 801 having. The plate 804 also has a full-surface hex mesh covering 806, which also covers the edge of the opening 805 and also extends to the underside of the plate 804.

The flap valve 900 is arranged below the opening 805, the dimensions and structure of which are as described above

Flap valve 700 substantially corresponds to the first embodiment. Deviations only result from the absence of a lining. This requires, for example, the provision of an additional front and rear wall plate 906a

® or 906b, each with a Hexmesh coating 806 or 806a. The plates 906a, 906b act - as in the first embodiment of the lining in this area - as flow guide walls for the FCC catalyst flowing through the open flap valve and contribute to avoiding excessive turbulence and high abrasive stress on the pipe lining.

The implementation of the invention is not limited to the examples described, but is also possible in a variety of modifications. The shape of the valve opening and - adapted to it - the flaps can be easily modified in accordance with the special application specifications. Shielding and baffle plates can be attached to the flaps themselves or to the valve seat. List of reference symbols

, 100 cracking plant

Shut-off or cut-off valve for slide valve (exhaust gas reusable valve) a Exhaust gas reusable valve, flap valve (shut-off valve) Wedge-in-wedge slider shut-off valve Shut-off valve Special check valve Line 0 Line 1 Feed pump 2 Intermediate tank 3, 113 Feed area 4, 114 Riser line 5, 115 Down pipe 6, 116 reactor, 117 regenerator, 118 plenum, 119 compressed air line, 120 catalyst discharge line, 121 plenum, 122 bulk line, 123 ', 123' flue gas line expansion turbine chimney boiler

Bypass line Bypass line, 30, 129, 130 Doppe1 lappenventi1 1 line 2 fractionation column

CORRECTED SHEET (RULE 91) ISA / EP 131, 133, 134 flap valve

132 Catalyst Recycle Line

135 discharge or Relaxation chamber 600 cold wall pipe section

601, 801 steel tube wall

602 refractory lining

603 lining funnel

604, 606, 802, 806 Hexmesh ^® liner 606a, 806a separate liner section

605, 805 opening 607, 807 opening

700, 900 flap valve

701a, 701b, 901a, 901b support and rotation axis 702a, 702b, 902a, 902b swing flap

703a, 703b, 903a, 903b Hexmesh ^® covering

704, 904 electro-hydraulic actuator

705, 905 steel plate 706 lining

707a, 707b, 907a, 907b retaining flange

708a, 708b, 908a, 908b guide sleeve

800 hot wall line

804 steel plate 906a front wall plate

906b back panel

A longitudinal line axis

S plane of symmetry

Claims

Patent claims

1. Fluid catalytic cracking system (1; 100) which has at least one line with a shut-off valve through which a bulk material-like catalyst mass flows, characterized in that the shut-off valve is a flap valve (700; 900) which has at least one flap (702a, 702b; 902a, 902b ) which can be pivoted about an axis of rotation (701a, 701b; 901a, 901b) lying to the side of a through opening (605; 805) in a cross-sectional plane of the line (600; 800).

2. Fluid catalytic cracking plant according to claim 1, having a reactor (16; 116), a regenerator (17; 117) connected to the latter via a bulk material line (22; 122) and a region (18; 118) for the feed which is lower in relation to the regenerator of hydrocarbons to be cracked, this area being connected via a hydrocarbon / catalyst riser (14; 114) to the reactor on the one hand and via a down pipe (15; 115) with a bottom outlet of the regenerator for supplying bulk-type catalyst mass from the regenerator on the other is connected, characterized in that a shut-off valve arranged in the downpipe (15; 115) and / or in the bulk material line (22; 122) between the reactor and the regenerator is a flap valve (29, 30; 129, 130), which is in particular two to the side of a through opening in a cross-sectional plane of the respective line lying axes of rotation pivotable flaps.

3. Fluid catalytic cracking plant according to claim 2, characterized in that in at least one other connected to the regenerator, flowed through by bulk catalyst mass, in particular a catalyst return line (132) and / or a catalyst discharge line (20; 120), a Flap valve (131; 133) is provided.

4. Fluid catalytic cracking system according to one of the preceding claims, d a d u r c h g e k e n n e e c h n e t that a flap valve, in particular as an exhaust gas pressure control valve, is provided in an exhaust pipe (123 ', 123' ').

5. Fluid catalytic cracking system according to one of the preceding claims, characterized in that at least in a part of the lines provided with a flap valve connecting piece for supplying a cleaning fluid, in particular a compressed gas, and / or for introducing emergency actuators in the direction of the flap or flaps of the Flap valve are provided.

6. Fluid catalytic cracking plant according to one of the preceding claims, characterized by an attachment of the flap valve (700; 900) substantially within the wall of the respective line (600; 800), in particular within a lining funnel (603) or below a metal plate (804) .

7. flap valve (700; 900), in particular for use in a fluid catalytic cracking plant according to one of claims 1-6, with at least one about an axis of rotation (701a, 701b; 901a, 901b), which in a cross-sectional plane of a line (600; 800) to the side of a through opening (605; 805), pivotable flap (702a, 702b; 902a, 902b), characterized in that two flaps are provided, the extension planes of which in the closed state each have an acute angle in the range between 30 ° and 60 °, in particular of 45 °, with the cross-sectional plane.

8. flap valve according to claim 7, d a d u r c h g e k e n n z e i c h n e t that both flaps (701, 701b; 901a, 901b) the same

Include angles with the cross-sectional plane.

9. Flap valve according to claim 7 or 8, characterized in that the flaps (701a, 701b; 901a, 901b) have a substantially rectangular cross-sectional shape and are dimensioned so differently that in the closed state the one flap (702b; 902b) with its through opening ( 605, 805) facing top hits the end face of the other flap (702a; 902a).

10. Flap valve according to one of claims 7-9, characterized in that the flaps (702a, 702b; 902a, 902b) have a wear-reducing coating, in particular, at least on their surface facing the through opening (605; 805) have a hex mesh covering (703a, 703b; 903a, 903b) with stamping out.

11. Flap valve according to claim 10, so that the wear-reducing coating also extends over the contact edge region of the flaps (702a, 702b; 902a, 902b).

12. Flap valve according to one of claims 7-11, d a d u r c h g e k e n n z e i c h n e t that the through opening (605; 805) has a substantially square or rectangular shape with rounded corner areas and the width of the through the flaps

(702a, 702b; 902a, 902b) in the opening position limited opening area is slightly larger than the width of the through opening.

13. Flap valve according to one of claims 7 - 12, characterized in that the flaps (702a, 702b; 902a, 902b) with the axes of rotation (701a, 701b; 901a, 901b) and a separate wall section (705; 706, 606a; 905) the line (600; 800) form an assembly that can be inserted into and removed from the line.

14. Flap valve according to one of claims 7-13, characterized in that in the line (600; 800) downstream of the through opening (605; 805) flow guide surfaces with a wear-reducing coating (606; 806), in particular a Hexmesh ^® coating with stamping out, are provided.