Quenching system and method for a quenching system for cooling cracked gas from a cracking gas furnace

Abstract

The invention relates to a quench system and a method for a quench system for cooling cracked gas from a cracked gas furnace with different feedstocks, comprising a cracked gas furnace (10), a primary quench exchanger or PQE (12), and a secondary quench exchanger connected in series. A transfer line exchanger or TLX for a cooling medium consisting of a gas mixture and water vapor, or a TLX-G / G (14), is arranged and configured as a secondary quench exchanger. The TLX-G / G (14) is connected in series to the primary quench exchanger or PQE (12) via a gas transfer line (13). A supply line (15) carrying the cooling medium consisting of the gas mixture and water vapor is arranged on the lower part of the TLX-G / G (14), upstream of the outlet head of the vertically oriented TLX-G / G. The TLX-G / G (14) is connected to the cracking gas furnace (10) via a return line (16) for the return of cooling medium preheated in the TLX-G / G.The TLX-G / G (14) is equipped with a pipeline (19) for cracking gas cooled to temperatures of 450°C to 300°C for further processing. A compensator (39) is provided at the upper end behind the inlet head of the cracking gas into the TLX-G / G (14).

Description

[0001] The invention relates to a quench system and a method for a quench system for cooling cracked gas from a cracked gas furnace.

[0002] To operate an ethylene furnace, also known as a cracking furnace, there are various feedstocks that are further processed in a cracking furnace. These feedstocks are heated to high temperatures in a cracking furnace and then rapidly cooled using a quench system, also known as QS for short.

[0003] Depending on the feedstock, a specially designed quench system or QS is required because the physical properties of the feedstocks vary. Gas as a feedstock can be cooled further, from approximately 900°C to 150°C, than a liquid feedstock, which is cooled from approximately 900°C to 350°C, because gas condensation only begins at significantly lower temperatures.

[0004] A liquid-feed quench system consists of a primary heat exchanger (PQE) and a secondary heat exchanger (SQE) connected in series. The PQE and SQE are each configured and operated as a vaporizer and evaporator, respectively.

[0005] EP 3 032 209 B1 is cited as prior art. EP 3 032 209 B1 discloses a quench cooling system consisting of a primary quench cooler as a double-tube heat exchanger and a secondary quench cooler as a tube-bundle heat exchanger comprising at least one tube bundle. The tube bundle is enclosed by a shell, forming a shell space formed between two spaced-apart tube sheets, between which bundle tubes of the tube bundle are held in the tube sheet on both sides.

[0006] US 8,158,840 B2 discloses a process and apparatus for steam cracking liquid hydrocarbon residues, wherein a steam / liquid separator is used to treat heated steam / liquid mixtures and provide a steam stream with reduced residue content. The process comprises indirect heat exchange of liquid distillate residues with feedwater or boiler feedwater to produce liquid distillate residues and preheated feedwater; discharging at least a portion of the preheated feedwater to a steam drum; and recovering steam with a steam pressure of at least about 4100 kPa from the steam drum. The apparatus comprises, among other things, a liquid-feed cracking furnace, a steam / liquid separator, a primary heat exchanger, and a secondary heat exchanger.

[0007] EP 1 939 412 B1 discloses a heat exchanger for cooling cracked gas in an ethylene plant. Heat exchanger tubes through which the cracked gas flows are inserted at their respective ends into a tube plate and surrounded by a shell, on each of whose two end faces an end chamber is provided for the supply and discharge of cracked gas, partially defined by one of the tube plates. The interior of the heat exchanger, enclosed by the shell, is traversed by water as the cooling medium. The interior of the heat exchanger is divided by a partition wall running perpendicular to the heat exchanger tubes and penetrated by the heat exchanger tubes into two sub-chambers arranged one behind the other in the flow direction of the cracked gas, each sub-chamber being provided with its own supply and discharge ports for the cooling medium.

[0008] Disadvantages of the applied arrangement of a quench system for cooling fission gases from a fission gas furnace are that the heat balance during cooling of fission gases has not yet been satisfactorily solved from an economic and ecological point of view.

[0009] A fission gas leaves a fission gas furnace at a temperature range of 800°C to 900°C at a pressure of 0.5 to 2 barg or 0.05 to 0.2 MPag. A heat exchanger arranged directly downstream of the fission gas furnace would have to be made of high-alloy steels if such a design were to be implemented. Such a design would be technically complex and economically very expensive compared to conventional technology. The costs are expected to be five to ten times higher. Therefore, it is quite practical to precool fission gases from a fission gas furnace in a conventional water / steam-cooled primary quench exchanger (PQE).

[0010] In a water / steam-cooled quench cooler, the material temperatures are significantly lower than in a gas-cooled quench cooler due, among other things, to the higher heat transfer. Pre-cooling of fission gases should have a temperature value of 700°C to 550°C, so that low- to medium-alloy steels can be used in a quench cooler for the further cooling of fission gases, significantly reducing costs and protecting the environment. The object of the invention is to create a quench system and a method for a quench system for cooling fission gases from a fission gas furnace with different starting materials, which improves the high requirements for technical and ecological design and operation in terms of reliability and costs and ensures simple options for necessary repair and maintenance work.

[0011] The present object of the invention is achieved generically by a quench system according to claim 1 and a method according to claim 6, wherein a transfer line exchanger for a cooling medium consisting of a gas mixture + water vapor or, in short, a TLX-G / G is arranged and designed as a secondary quench exchanger, that the TLX-G / G is connected in series with a primary quench exchanger or PQE via a gas transfer line which is attached to the inlet end of a cracked gas into the TLX-G / G, and that the TLX-G / G is connected to the cracked gas furnace via a return line of preheated cooling medium.

[0012] Furthermore, the TLX-G / G is equipped with a supply line for a cooling medium consisting of HC + steam. A discharge line for cooled fission gas is located at the outlet end of the TLX-G / G.

[0013] Furthermore, the TLX-G / G is connected to the cracked gas furnace via a return line for preheated cooling medium. Furthermore, a supply line carrying the cooling medium, consisting of a gas mixture and steam, is located at the lower part of the TLX-G / G, upstream of the outlet head of the vertically aligned TLX-G / G.

[0014] The TLX-G / G is advantageously connected to the cracked gas furnace via a return line for returning the cooling medium preheated in the TLX-G / G, consisting of hydrocarbon gas+steam or hydrocarbon+steam or HC+steam for short.

[0015] In addition, the TLX-G / G is equipped with a pipeline for the transfer of fission gas cooled to temperatures of 450°C to 300°C for further processing.

[0016] At the upper end of the TLX-G / G, a compensator is preferably provided behind the inlet head of the fission gas.

[0017] A gas inlet nozzle for the supply line of a cooling medium is advantageously arranged on the shell of the TLX-G / G. A number of baffles are preferably mounted in the shell space of the TLX-G / G, the number of which is determined depending on the respective predetermined load case. The cooling medium is directed around the baffles of the TLX-G / G in a countercurrent process, alternating by 180° around the outside of bundled tubes.

[0018] Furthermore, a gas outlet nozzle for the return line of the preheated cooling medium is preferably arranged on the shell of the TLX-G / G at the upper end in front of the inlet head of the vertically aligned TLX-G / G. In the shell space of the TLX-G / G, segments free of tube bundles are advantageously provided in the areas of the baffles.

[0019] The size of the free-flow segment is preferably between 10% and 20% of the cross-sectional area of ​​the inner diameter of the TLX-G / G shell.

[0020] The bundle tubes of the TLX-G / G are advantageously arranged in a triangular division for a flow of a cooling medium, wherein the side length of the triangle is 1.2 times to 1.3 times the tube diameter of a bundle tube.

[0021] A compensator is advantageously installed around the shell of the TLX-G / G at the upper end behind the inlet head of the fission gas from the TLX-G / G to compensate for different thermal expansions between the bundle tube and the shell.

[0022] In the shell area of ​​the TLX-G / G, cleaning nozzles are preferably located close to the tubesheet of the fission gas outlet head of a vertically aligned TLX-G / G. Two to four closable cleaning nozzles, each with a diameter of 200 mm to 500 mm, are preferably provided in the shell area of ​​the TLX-G / G, with the cleaning nozzles being mounted at a distance of 100 mm to 200 mm from the lower tubesheet.

[0023] In a horizontally aligned TLX-G / G, two to four cleaning nozzles, each with a diameter of 200 mm to 500 mm, are provided lengthwise in the lower area of ​​the shell space, depending on the predetermined degree of contamination by coke deposits.

[0024] In a method for a quench system for cooling cracked gas from a cracked gas furnace with different feedstocks, which comprises a cracked gas furnace, a primary quench exchanger, and a secondary quench exchanger connected in series, it is considered particularly advantageous if a transfer line exchanger for a cooling medium consisting of a gas mixture and steam, or a TLX-G / G, is arranged and configured as a secondary quench exchanger. The TLX-G / G is connected in series to the primary quench exchanger or PQE via a gas transfer line.

[0025] Advantageously, a supply line conducting the cooling medium to the gas mixture and steam is arranged at the lower part of the TLX-G / G before the inlet head of the vertically aligned TLX-G / G. The TLX-G / G is preferably connected to the cracked gas furnace via a return line for returning the cooling medium preheated in the TLX-G / G. Furthermore, the TLX-G / G is equipped with a pipeline for supplying cracked gas cooled to temperatures of 450°C to 300°C for further processing.

[0026] A particular advantage is that a compensator is provided at the upper end behind the inlet head of the fission gas into the TLX-G / G.

[0027] Another advantage is that a gas inlet nozzle for the supply line of a cooling medium is arranged on the jacket of the TLX-G / G at the lower part in front of the outlet head of a vertically aligned TLX-G / G.

[0028] It is also advantageous to install a number of baffles in the shell of the TLX-G / G, the number of which is determined and dependent on the respective predetermined load case. The cooling medium is advantageously guided around the baffles of the TLX-G / G in a countercurrent process, alternating by 180° around the outside of the bundled tubes. A gas outlet nozzle for the return line of the preheated cooling medium is particularly advantageously arranged on the shell of the TLX-G / G at the upper end in front of the inlet head of a vertically aligned TLX-G / G.

[0029] Furthermore, in the shell space of the TLX-G / G, segments free of tube bundles are advantageously provided in the areas of the baffles.

[0030] The size of the free-flow segment is preferably between 10% and 20% of the cross-sectional area of ​​the inner diameter of the TLX-G / G shell. The bundled tubes of the TLX-G / G are preferably arranged in a triangular configuration for the flow of a cooling medium, with the side length of the triangle being 1.2 to 1.3 times the diameter of a bundled tube.

[0031] A compensator is advantageously installed around the shell of the TLX-G / G at the upper end behind the inlet head of the fission gas from the TLX-G / G to compensate for different thermal stresses between the bundle tubes and the shell.

[0032] Furthermore, in the area of ​​the shell space of the TLX-G / G, cleaning nozzles are preferably arranged close to the tube bottom of the fission gas outlet head of a vertically aligned TLX-G / G.

[0033] Preferably, two to four closable cleaning nozzles, each with a diameter of 200 mm to 500 mm, are provided in the area of ​​the shell space of the TLX-G / G, with the cleaning nozzles being mounted at a distance of 100 mm to 200 mm from the lower tube sheet of the outlet head of the TLX-G / G.

[0034] A further advantage of a horizontally aligned TLX-G / G is that, after a predetermined degree of contamination by coke deposits, two to four cleaning nozzles, each with a diameter of 200 mm to 500 mm, are provided lengthwise in the lower area of ​​the shell space.

[0035] Further details and advantages of the invention are explained in more detail with reference to an embodiment illustrated in the drawing. They show: Fig. 1 a schematic arrangement of a quench system for cooling a cracked gas from a cracked gas furnace for a gas-cooled quench cooler according to the invention; Fig. 2 a schematic arrangement in section with the detail AA for a quench cooler of a quench system according to the invention, cooled with a jacket-side gas guide according to the countercurrent principle; Fig. 3 a schematic arrangement of the bundled tubes in the tube field according to Fig. 2 with detail AA on an enlarged scale for a quench cooler of a quench system according to the invention; Fig. 4 a schematic arrangement of a compensator for a quench cooler of a quench system according to the invention; Fig. 5 a schematic arrangement of cleaning nozzles on the jacket of a vertically aligned quench cooler of a quench system according to the invention and Fig. 6 a schematic arrangement of cleaning nozzles on the jacket of a horizontally aligned quench cooler of a quench system according to the invention.

[0036] In Fig. 1 A schematic arrangement of a quench system for operating a cracked gas furnace 10 for a gas-cooled quench cooler is shown. The quench cooler is arranged and designed as a transfer line exchanger (TLX) for a cooling medium consisting of a gas mixture and steam, or in short, a TLX-G / G 14 as a secondary quench exchanger. The TLX-G / G 14 is connected in series with a primary quench exchanger (PQE 12) and the cracked gas furnace 10.

[0037] Coils 11 are arranged upstream of the cracked gas furnace 10, leading to the indicated primary quench exchanger or PQE 12 as a precooler. In the conventional PQE 12, which serves as a precooler, cracked gases are precooled to approximately 700°C to 550°C or lower. The PQE 12 is equipped with an inlet nozzle 17 and an outlet nozzle 18. Cooling water is fed in via the inlet nozzle 17, and the water / steam mixture produced during precooling is passed on via the outlet nozzle 18.

[0038] A well-known function of the PQE 12 will not be discussed further below. The PQE 12, as a pre-cooler, is intended solely to pre-cool the high temperatures of the fission gases from 800°C to 900°C from the fission gas furnace 10 to a temperature of approximately 700°C to 550°C. This significantly simplifies and significantly reduces the material selection and associated costs for the TLX-G / G 14, which is connected in series with the PQE 12.

[0039] The TLX-G / G 14 is connected in series with the PQE 12 via a gas transfer line 13. The pre-cooled fission gas from the PQE 12 is piped into the TLX-G / G 14 via the gas transfer line 13. In the TLX-G / G 14, the fission gas is further cooled to temperatures of 450°C to 300°C. A fission gas is discharged via a pipeline 19 for further processing.

[0040] A supply line 15 for the cooling medium consisting of a gas mixture and steam or hydrocarbon gas and steam or hydrocarbon and steam, or HC+steam for short, is arranged at the lower end upstream of the outlet head of the vertically aligned TLX-G / G 14. A gas mixture of HC+steam at a temperature of 200°C to 290°C is supplied to the TLX-G / G 14 via the supply line 15 on the shell side and flows through the TLX-G / G in a countercurrent process.

[0041] A return line 16 is located at the upper end before the inlet head of the TLX-G / G 14 and leads to the cracked gas furnace 10. The gas mixture of HC+steam, preheated to 400°C to 550°C in the TLX-G / G 14, is returned to the cracked gas furnace 10 via the return line 16. In the cracked gas furnace 10, the already preheated gas mixture of HC+steam is further heated to 800°C to 900°C, cracking the gas mixture of HC+steam. The cracked gas mixture, or cracked gas, is then fed back to the PQE 12 as a precooler. The process is repeated.

[0042] The exact function of a cracked gas furnace will not be discussed in detail here, as its function is well known in technology.

[0043] In Fig. 2 A schematic arrangement in section with detail AA is shown for a quench cooler of a quench system cooled with shell-side gas flow using the countercurrent principle. The indicated TLX-G / G 14 is shown with the gas transfer line 13 arranged at the gas inlet and the pipe 19 attached to the gas outlet. On a pipe inner side 35 shown in section AA, the pre-cooled cracking gas or cracking effluent flows straight through the TLX-G / G 14 from the gas transfer line 13 at the gas inlet to the gas outlet of the pipe 19, where it is cooled in the process.

[0044] The gas mixture of HC+water vapor is introduced into a jacket space 30 of the TLX-G / G 14 via a gas inlet nozzle 31 located at the lower end in front of the outlet head of the vertically oriented TLX-G / G and is guided by baffles 33 arranged in the jacket space of the TLX-G / G, alternating 180° several times during the flow around the outside of the bundled tubes 36. The HC+water vapor mixture leaves the TLX-G / G 14 via a gas outlet nozzle 32 located at the upper end in front of the inlet head of the vertically oriented TLX-G / G.

[0045] The number of baffles 33 depends on the respective predetermined load case and is determined accordingly. The pressure loss in the shell space 30 is high, particularly due to the repeated deflections of the HC+water vapor mixture, and must be reduced to a minimum to maintain good quench system efficiency. Therefore, a tube bundle / tube array 37 should be designed particularly well so that no bundle tubes 36 are located in the area of ​​a segment 34 through which the gas flows. The segments 34 remaining free of bundle tubes 36 contribute significantly to reducing the pressure loss and are essential for the process. The size of the segment 34 through which the gas flows freely lies between 10% and 20% of the cross-sectional area of ​​the shell inner diameter and depends on the respective predetermined load case.

[0046] In Fig. 3 is a schematic arrangement of the bundle tubes 36 of a tube bundle / tube array 37 according to Fig. 2 Shown in detail at section AA. The arrangement of the bundled tubes 36 must be particularly well-designed if, during a flow 41 of the HC+water vapor mixture, only a low pressure loss is to occur, but high heat transfer and no stagnation is to occur, so that high cooling is achieved. The tube arrangement is preferably designed in a triangular pitch 42 to achieve high cooling, with the side length of the triangle being 1.2 to 1.3 times the tube outer diameter 43.

[0047] In Fig. 4 A schematic arrangement of a compensator for a TLX-G / G quench cooler of a quench system according to the invention is shown. Due to the very low heat transfer values, the material temperatures in the TLX-G / G 14 are high, and the temperature difference between the bundled tubes 36 and the shell 38 is also very high. The mechanical stresses occurring between the bundled tubes 36 and the shell 38 due to the different thermal expansion must be compensated. Therefore, a compensator 39 is provided around the outer shell space 30 at the upper end behind the inlet head of a vertically aligned TLX-G / G 14.

[0048] In Fig. 5 is a schematic arrangement according to Fig. 4 of cleaning nozzles on a TLX-G / G quench cooler of a quench system. Due to the cooling medium consisting of HC + water vapor conducted in the shell space 30, it cannot be ruled out that deposits will form in the TLX-G / G 14 during operation, which deposits must be removed. In the vertically aligned TLX-G / G 14, closable cleaning nozzles 40 for removing deposits are provided in the lower area near the outlet head on the shell 38. Depending on the predetermined degree of contamination from possible coke deposits, two to four cleaning nozzles 40, each measuring 200 mm to 500 mm, are to be provided. The cleaning nozzles should preferably be arranged close to the lower tubesheet 44 of the TLX-G / G 14 with a spacing of approximately 100 mm to 200 mm.

[0049] In Fig. 6A schematic arrangement of cleaning nozzles on a TLX-G / G quench cooler of a quench system is shown. In the horizontally aligned TLX-G / G 14, closable cleaning nozzles 40 are provided on the shell 38 for removing deposits resulting from the cooling medium consisting of HC+steam conveyed in the shell space 30, extending lengthwise in the lower region of the shell. Depending on the predetermined degree of contamination by coke deposits, which cannot be ruled out, two to four cleaning nozzles 40, each with a diameter of 200 mm to 500 mm, are provided.

[0050] The advantages of the preferred TLX-G / G quench cooler for a quench system are that cracked gases are heated and cracked in a cracked gas furnace, pre-cooled by a primary quench exchanger or PQE, and then passed through the TLX-G / G on the tube side and further cooled.

[0051] Unlike conventional quench coolers, the TLX-G / G does not use a water / steam mixture as the cooling medium on the shell side, but rather a gas mixture and steam consisting of hydrocarbon gas and steam, or HC+steam for short. Such a mixture of HC+steam is preheated in the TLX-G / G and simultaneously cools cracking gases or cracking effluent from a cracking gas furnace, which are used for ethylene and subsequently for plastics production. The preheated mixture of HC+steam is returned to the cracking gas furnace for further heating, cracked in the cracking gas furnace, and then fed back into the TLX-G / G via the PQE.

[0052] The advantageous process or heat recovery reduces the energy required to heat a cracked gas furnace, which has a very positive economic and ecological impact on the overall process in terms of costs and consumption.

[0053] A conventional PQE should be used as a pre-cooler upstream of the TLX-G / G in order to operate the cracked gas furnace economically not only during initial operation, but also generally during planning, implementation and subsequent repairs or maintenance work. List of reference symbols

[0054] 1 2 3 4 5 6 7 8 9 10 Cracked gas furnace 11 Coils 12 Primary heat exchanger or PQE pre-cooler 13 Gas transfer line 14 TLX-G / G as quench cooler 15 Feed line HC+Steam 16 Return line HC+Steam 17 Feed nozzle 18 Discharge nozzle 19 Pipe 20-29 free 30 Shell space 31 Gas inlet nozzle 32 Gas outlet nozzle 33 Deflector plates 34 Segments 35 Tube inside 36 Bundled tubes 37 Tube bundle / tube field 38 Shell 39 Compensator 40 Cleaning nozzle 41 Flow indicated by arrows 42 Triangular division 43 Tube outside diameter 44 Tube sheet

Claims

1. Quench system for cooling cracked gas from a cracked gas furnace with different starting materials, which comprises a cracked gas furnace (10), a primary quench exchanger or PQE (12) and a secondary quench exchanger connected in series, characterized in thata transfer line exchanger or TLX for a cooling medium consisting of a gas mixture and water vapor or a TLX-G / G (14) is arranged and designed as a secondary quench exchanger, that the TLX-G / G (14) is connected in series with the primary quench exchanger or PQE (12) via a gas transfer line (13), that a feed line (15) conducting the cooling medium consisting of a gas mixture and water vapor is arranged on the TLX-G / G (14) at the lower part in front of the outlet head of the vertically aligned TLX-G / G, that the TLX-G / G (14) is connected via a return line (16) to the cracked gas furnace (10) for returning cooling medium preheated in the TLX-G / G, that the TLX-G / G (14) is connected via a pipeline (19) from temperatures of 450°C to 300°C cooled fission gas is equipped for further processing and that a compensator (39) is provided at the upper end of the TLX-G / G (14) behind the inlet head of the fission gas.

2. Quench system according to claim 1, characterized in thata gas inlet nozzle (31) for the supply line (15) of the cooling medium is arranged on the jacket (38) of the TLX-G / G (14), that deflection plates (33) are arranged in the jacket space (30) of the TLX-G / G (14), that the cooling medium is guided around the deflection plates (33) of the TLX-G / G (14) in a countercurrent process alternating by 180° around the outside of bundled tubes (36), that a gas outlet nozzle (32) for the return line (16) of the preheated cooling medium is arranged on the jacket (38) of the TLX-G / G (14) at the upper end in front of the inlet head of the vertically aligned TLX-G / G, that in the jacket space (30) of the TLX-G / G (14) in areas of the deflection plates (33) segments (34) are free of tube bundles (37).

3. Quench system according to claim 2, characterized in that the size of the freely flowing segment (34) is between 10% and 20% of the cross-sectional area of the inner diameter of the shell (38) of the TLX-G / G (14).

4. Quench system according to claim 2, characterized in that the bundle tubes (36) of the TLX-G / G (14) are arranged in a triangular division (42) for a flow (41) of a cooling medium and that the side length of the triangle is 1.2 times to 1.3 times a tube diameter (43) of a bundle tube (36).

5. Quench system according to claim 1, characterized in that A compensator (39) is installed around the jacket (38) of the TLX-G / G (14) at the upper end behind the inlet head of the fission gas from the TLX-G / G to compensate for different thermal expansions between the bundle tube (36) and the jacket (38).

6. Quench system according to claim 1, characterized in that in the area of the jacket space (30) of the TLX-G / G (14), cleaning nozzles (40) are arranged close to the tube bottom (44) of the outlet head of the fission gas of a vertically aligned TLX-G / G.

7. Quench system according to claim 6, characterized in thatin the area of the jacket space (30) of the TLX-G / G (14) two to four closable cleaning nozzles (40) each with a diameter of 200 mm to 500 mm are provided and that the cleaning nozzles (40) are mounted at a distance of 100 mm to 200 mm from the lower tube sheet (44).

8. Quench system according to claim 1, characterized in that in a horizontally aligned TLX-G / G (14), two to four cleaning nozzles (40) each with a diameter of 200 mm to 500 mm are provided lengthwise in the lower area of the shell space (30) after a predetermined degree of contamination by coke deposits.

9. A method for a quench system for cooling cracked gas from a cracked gas furnace with different starting materials, which comprises a cracked gas furnace (10), a primary quench exchanger or PQE (12) and a secondary quench exchanger connected in series, according to claim 1, characterized in thatTransfer line exchanger or TLX for a cooling medium consisting of a gas mixture and water vapor or a TLX-G / G (14) is arranged and designed as a secondary quench exchanger, that the TLX-G / G (14) is connected in series with the primary quench exchanger or PQE (12) via a gas transfer line (13), that a feed line (15) conducting the cooling medium consisting of a gas mixture and water vapor is arranged on the TLX-G / G (14) at the lower part in front of the outlet head of the vertically aligned TLX-G / G, that the TLX-G / G (14) is connected via a return line (16) to the cracked gas furnace (10) for returning cooling medium preheated in the TLX-G / G, that the TLX-G / G (14) is connected via a pipeline (19) from temperatures of 450°C to 300°C cooled fission gas is equipped for further processing and that a compensator (39) is provided at the upper end behind the inlet head of the fission gas into the TLX-G / G (14).

10. Method for a quenching system according to claim 9, characterized in that a gas inlet nozzle (31) for the supply line (15) of the cooling medium is arranged on the jacket (38) of the TLX-G / G (14), a number of deflection plates (33) are arranged in the jacket space (30) of the TLX-G / G, the number of which depends on the respective predetermined load case and is determined, that the cooling medium is guided around the deflection plates (33) of the TLX-G / G in a countercurrent process alternately by 180° around the outside of bundled tubes (36), that a gas inlet nozzle (32) for the return line (16) of the preheated cooling medium is arranged on the jacket (38) of the TLX-G / G (14) at the upper end in front of the inlet head of the vertically aligned TLX-G / G, and that segments are arranged in the jacket space (30) of the TLX-G / G (14) in areas of the deflection plates (33) (34) free of tube bundles (37).

11. Method for a quenching system according to claim 10, characterized in thatthe size of the freely flowing segment (34) is dimensioned between 10% and 20% of the cross-sectional area of the inner diameter of the shell (38) of the TLX-G / G (14).

12. Method for a quenching system according to claim 10, characterized in that the bundle tubes (36) of the TLX-G / G (14) are arranged in a triangular division (42) for a flow (41) of a cooling medium and that the side length of the triangle should be 1.2 times to 1.3 times a tube diameter (43) of a bundle tube (36).

13. Method for a quenching system according to claim 9, characterized in that around the jacket (38) of the TLX-G / G (14) at the upper end behind the inlet head of the fission gas from the TLX-G / G, a compensator (39) is installed to compensate for different thermal stresses between the bundle tube (36) and the jacket (38).

14. Method for a quenching system according to claim 9, characterized in thatin the area of the jacket space (30) of the TLX-G / G (14), cleaning nozzles (40) are arranged close to the tube bottom (44) of the outlet head of the fission gas of a vertically aligned TLX-G / G.

15. Method for a quenching system according to claim 14, characterized in that in the area of the jacket space (30) of the TLX-G / G (14) two to four closable cleaning nozzles (40) each with a diameter of 200 mm to 500 mm are provided and that the cleaning nozzles (40) are mounted at a distance of 100 mm to 200 mm from the lower tube sheet (44) of the outlet head of the TLX-G / G.

16. Method for a quenching system according to claim 9, characterized in that In the case of a horizontally aligned TLX-G / G (14), two to four cleaning nozzles (40) each with a diameter of 200 mm to 500 mm are provided lengthwise in the lower area of the shell space (30) according to a predetermined degree of contamination by coke deposits.

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