Quick cooling system for cooling decomposition gas from decomposition gas furnace and process for quick cooling system

Abstract

To provide a quick cooling system for cooling decomposition gas from a decomposition gas furnace using different raw materials, and a process for the quick cooling system.SOLUTION: This invention relates to a quick cooling system for cooling decomposition gas from a decomposition gas furnace by using different raw materials and a process for the quick cooling system. The quick cooling system is configured by connecting a decomposition gas furnace 10, a primary quick cooling exchanger, that is PQE 12 and a transfer line exchanger using mixed gas and steam as a cooling medium, that is TLX-G / G 14 in series as a secondary quick cooling exchanger. The TLX-G / G 14 is connected to the decomposition gas furnace 10 via a return line 16 for returning the cooling medium preheated by TLX-G / G.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a quench system and a process for a quench system for cooling cracked gas from a cracked gas furnace. [Background technology]

[0002] To operate an ethylene furnace, also called cracker gas furnace or cracker, there are various feedstocks that are further processed in the cracker, where they are heated to high heat and then cooled in a quench system, also called QS for short.

[0003] Different physical properties of the feedstocks require different configurations of quenching systems or QS. A gas feedstock may be cooled much more dramatically, for example from about 900°C to 150°C, than a liquid feedstock, which is cooled from about 900°C to 350°C, since condensation of the gas starts at a significantly lower temperature.

[0004] A liquid feed mode quench system consists of a primary heat exchanger, abbreviated PQE, and a secondary heat exchanger, abbreviated SQE, connected in series, where the PQE and SQE are connected as evaporators and evaporators respectively and operated by themselves.

[0005] EP 3032209 B1 may be relevant as an example of the prior art. A quenching system is known from EP 3032209 B1, which comprises a primary quenching device as a double-pipe heat exchanger and a tube bundle heat exchanger as a secondary quenching device with at least one tube bundle. The tube bundle is surrounded by a jacket, forming a jacket space. This jacket space is formed between two tube sheets arranged at a distance from each other, and a plurality of converging pipes of the tube bundle are held by the tube sheets on both sides.

[0006] A process and an apparatus for cracking liquid hydrocarbon residues with steam are known from US 8,158,840 B2, in which a steam / liquid separator is used to treat a heated steam / liquid mixture and ensure a steam stream with reduced residue content. The process comprises indirect heat exchange of the liquid distillation residue with feedwater or boiler feedwater to provide the liquid distillation residue and preheated feedwater, bypassing at least a portion of the preheated feedwater to a steam drum, and recovering steam from the steam drum having a steam pressure of at least about 4100 kPa. The apparatus comprises not only primary and secondary heat exchangers, but also a liquid feed cracking furnace, a steam / liquid separator, etc.

[0007] A heat exchanger for cooling cracked gases in an ethylene plant is known from EP 1939412 B1, in which the heat exchanger tubes through which the cracked gases flow are inserted at each end into one tube plate and surrounded by a jacket. At both end faces of the jacket there are end chambers, partially bounded by one of the tube plates, provided for the supply and discharge of the cracked gases. As cooling medium, water flows through the inner space of the heat exchanger. This inner space is surrounded by a jacket and divided into two partial spaces, one behind the other, along the direction of flow of the split gases. The partial spaces are each provided with their own supply and discharge pipes for the cooling medium and are separated by a partition which runs perpendicular to the heat exchanger tubes and through which the heat exchanger tubes pass. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] European Patent Publication No. 3032209 (corresponding Japanese Patent Publication No. 2016-114349) [Patent Document 2] U.S. Patent Publication No. 8,158,840 [Patent Document 3] European Patent Publication No. 1939412 (corresponding to Japanese Patent Publication No. 2008-145097) Summary of the Invention [Problem to be solved by the invention]

[0009] The disadvantage of the arrangement of quenching systems applied to cool the cracked gas from the cracking gas furnace is that the thermal balance during the cooling of the cracked gas has not been achieved to a satisfactory extent so far, from the economic and environmental point of view. The cracked gas leaves the cracking gas furnace at a temperature range of 800 ° C to 900 ° C and a pressure of 0.5 bar to 2 bar or 0.05 Mpag to 0.2 Mpag. When realizing such a structure, the heat exchanger arranged immediately after the cracking gas furnace must be manufactured from high alloy steel. Such an arrangement is technically highly laborious and economically very expensive compared to conventional technologies. It is considered to cost 5 to 10 times more. It is therefore absolutely appropriate to precool the cracked gas from the cracking gas furnace with a conventional primary quench exchanger, i.e. PQE, cooled by water / steam.

[0010] In the case of water / steam cooled quench coolers, the material temperature is significantly lower than in the case of gas cooled quench coolers, due to the higher transfer rate among other factors. The pre-cooling of the cracked gases should have a temperature of 700°C to 550°C, which allows low to medium alloy steels to be used in the quench cooler to further cool the cracked gases, significantly reducing costs and protecting the environment.

[0011] The object of the present invention is to provide a quenching system and a process for quenching the cracking gas from a cracking gas furnace using different raw materials, which improves the high demands imposed on the technical and environmental arrangement and operation method in terms of reliability and costs, and guarantees simplicity in terms of necessary repairs and maintenance. [Means for solving the problem]

[0012] The object of the present invention is generally achieved by a quench system as set forth in claim 1 and a process as set forth in claim 9, in which a transfer line exchanger for a cooling medium consisting of mixed gas+steam, i.e. TLX-G / G, is arranged and configured as a secondary quench exchanger, which is connected in series with a primary quench exchanger, i.e. PQE, via a gas transfer line, which is attached to an inlet end of cracked gas in the TLX-G / G, and which is connected to a cracked gas furnace via a return line of preheated cooling medium.

[0013] The TLX-G / G also has a supply line for the cooling medium consisting of HC+ vapor. An exhaust line for the cooled cracked gases is located at the outlet end of the TLX-G / G.

[0014] In addition, the TLX-G / G is connected to the cracking gas furnace through a return line for preheated cooling medium, and a supply line for transporting the cooling medium consisting of mixed gas and steam is located at the bottom of the vertically oriented TLX-G / G, just before (close to) the outlet header.

[0015] The TLX-G / G is advantageously connected to the cracked gas furnace via a return line for returning a cooling medium consisting of hydrocarbon gas + steam or hydrocarbon + steam, abbreviated as HC + steam, preheated in the TLX-G / G.

[0016] In addition, the TLX-G / G is equipped with a pipeline to send the cracked gas, cooled to a temperature range of 450°C to 300°C, for further processing.

[0017] At the top end of the TLX-G / G, a compensator is preferably provided aft of (a short distance from) the cracked gas inlet header. A gas inlet pipe for the cooling medium supply line is advantageously located in the jacket of the TLX-G / G. The jacket space of the TLX-G / G is preferably provided with a number of baffles determined according to a given load case. The cooling medium is guided alternately every 180° around the outside of the bundle tubes in a counterflow process around the baffles of the TLX-G / G.

[0018] Furthermore, a gas discharge pipe for the return line of the preheated cooling medium is preferably arranged in the jacket of the TLX-G / G at the upper end of the vertically arranged TLX-G / G, before the inlet header. In the region of the baffles in the jacket space of the TLX-G / G, a segment without tube bundles is advantageously provided.

[0019] The size of the free flow segment is preferably sized to be between 10% and 20% of the cross-sectional area of ​​the inside diameter of the TLX-G / G jacket.

[0020] The bundle tubes of the TLE-G / G are advantageously arranged in a triangular configuration relative to the flow of the cooling medium, with the side length of the triangle being 1.2 to 1.3 times the outer diameter of the bundle tube.

[0021] A compensator, which compensates for the differential thermal expansion between the bundle tubes and the jacket, is advantageously installed around the jacket at the top of the TLX-G / G, aft of the cracked gas inlet header.

[0022] Preferably, a cleaning pipe is arranged in the region of the jacket space of the TLX-G / G near the tube sheet of the cracked gas outlet header of the vertically oriented TLX-G / G, in which case, preferably, two to four closable cleaning pipes having a diameter of 200 mm to 500 mm are provided in the region of the jacket space of the TLX-G / G, the cleaning pipes being mounted at a distance of 100 mm to 200 mm from the lower tube sheet.

[0023] Depending on the given level of contamination by coke deposits, in the case of a horizontally arranged TLX-G / G, two to four washing pipes with a diameter of 200 mm to 500 mm are provided vertically in the lower area of ​​the jacket space.

[0024] In the case of a process of a quench system for cooling cracked gas from a cracked gas furnace using different raw materials, it is considered particularly advantageous if the cracked gas furnace, the primary quench exchanger and the secondary quench exchanger are connected in series and a transfer line exchanger for a cooling medium consisting of mixed gas and steam, i.e. TLX-G / G, is arranged and configured as the secondary quench exchanger, in which case the TLX-G / G is connected in series to the primary quench exchanger, i.e. PQE, via a gas transfer line.

[0025] In the TLX-G / G, a supply line for transporting a cooling medium consisting of mixed gas and steam is advantageously arranged at the bottom of the vertically arranged TLX-G / G before the outlet header. 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 further processing the cracked gas cooled to a temperature range of 450°C to 300°C.

[0026] At the upper end of the TLX-G / G it is particularly advantageous to provide a compensator after the cracked gas inlet header.

[0027] It is also advantageous that a gas inlet pipe for the cooling medium supply line is arranged in the jacket of the TLX-G / G at the lower end of the vertically arranged TLX-G / G, before the outlet header.

[0028] Furthermore, it is advantageous if several baffles are fitted in the jacket space of the TLX-G / G, the number of which is determined by the respective given load case. In this case, the cooling medium is advantageously guided around the baffles of the TLX-G / G in a counterflow process around the outside of the bundle tubes by 180° alternately. A gas outlet pipe for the return line of the preheated cooling medium is particularly advantageously arranged in the jacket of the TLX-G / G at the top end of the vertically arranged TLX-G / G before the inlet header.

[0029] Furthermore, the baffle region of the jacket space of the TLX-G / G is advantageously provided with segments free of tube bundles.

[0030] The size of the free flow segment is preferably sized between 10% and 20% of the cross-sectional area of ​​the inside diameter of the TLX-G / G jacket. The TLX-G / G bundle tubes are preferably arranged in a triangular configuration relative to the coolant flow, with the side length of the triangle being 1.2 to 1.3 times the bundle tube outside diameter.

[0031] A compensator, which compensates for differences in thermal expansion between the bundle tubes and the jacket, is advantageously installed around the jacket at the upper end of the TLX-G / G, aft of the cracked gas inlet header.

[0032] Additionally, it is preferred that a cleaning pipe be located near the tubesheet of the cracked gas outlet header of the vertically oriented TLX-G / G in the region of the jacket space of the TLX-G / G.

[0033] In the region of the jacket space of the TLX-G / G, two to four closable wash pipes having a diameter of 200 mm to 500 mm are preferably provided, the wash pipes being mounted at a distance of 100 mm to 200 mm from the lower tube sheet of the outlet header of the TLX-G / G.

[0034] Another advantage is that in the case of the horizontally arranged TLX-G / G, two to four cleaning pipes with a diameter of 200 mm to 500 mm are provided vertically in the lower area of ​​the jacket space, depending on the given level of contamination by coke deposits.

[0035] Further details and advantages of the invention will be explained in more detail on the basis of an embodiment shown in the drawings. [Brief description of the drawings]

[0036] [Figure 1] 1 shows a schematic arrangement of a quench system for cooling cracked gases from a cracked gas furnace for a gas-cooled quencher according to the invention; [Diagram 2] FIG. 2 shows a detail of section AA in a cross-sectional view of the quench of the quenching system according to the invention, showing how the cooler induces and cools gas on the jacket side according to the counterflow principle. [Diagram 3] 3 shows a schematic arrangement of bundle tubes in the tubesheet of FIG. 2 for a quench of a quenching system according to the invention, with detail of section AA shown on an enlarged scale. [Figure 4] 2 shows a schematic arrangement of a compensator for a quench of a quench system according to the present invention; [Diagram 5] 2 shows a schematic arrangement of wash pipes in the jacket of a vertically oriented quencher of a quenching system according to the present invention; [Figure 6] 4 shows a schematic arrangement of wash pipes in the jacket of a transversely positioned quencher of a quenching system according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] 1 shows a schematic arrangement of a quench system for operating a cracking gas furnace 10 for a gas-cooled quench. The quench is arranged and configured as a transfer line exchanger or TLX for a cooling medium consisting of a mixed gas and steam, and serves as a secondary quench exchanger, called TLX-G / G 14 for short. The TLX-G / G 14 is connected in series with the primary quench exchanger or PQE 12 and the cracking gas furnace 10.

[0038] The coil 11 is placed before the cracked gas furnace 10 and leads to the proposed primary quench exchanger or precooler PQE 12. In the conventional precooler PQE 12, the cracked gas is precooled from about 700°C to below 550°C. The PQE 12 is provided with a feed water pipe 17 and an exhaust pipe 18. Cooling water is supplied through the feed water pipe 17 and the water / steam mixture formed during precooling is sent through the exhaust pipe 18.

[0039] The known function of the PQE 12 will not be described further below. The PQE 12 as a precooler only precools the hot cracked gases of 800°C to 900°C from the cracked gas furnace 10 to about 700°C to 550°C. Then the material selection and associated costs of the TLX-G / G 14 connected in series with the PQE 12 are greatly simplified and significantly reduced.

[0040] The TLX-G / G 14 is connected in series to the PQE 12 via gas transfer line 13. Pre-cooled cracked gas from the PQE 12 is delivered through gas transfer line 13 to the tube side in the TLX-G / G.

[0041] The split gas is further cooled in TLX-G / G 14 from 450°C to a temperature of 300°C. The split gas is branched off through pipeline 19 for further processing.

[0042] A feed line 15 is placed before the outlet header at the lower end of the vertically arranged TLX-G / G 14 for the cooling medium consisting of mixed gas and steam, or hydrocarbon gas and steam, or hydrocarbon and steam, or HC + steam for short. A mixed gas consisting of HC + steam with a temperature of 200°C to 290°C is fed via the feed line 15 to the jacket side and passes through the TLX-G / G in a countercurrent process.

[0043] A return line 16 is located at the top of the TLX-G / G 14 before the inlet header and leads to the cracked gas furnace 10. The HC + steam mixed gas, preheated to 400°C to 550°C in the TLX-G / G 14, is returned to the cracked gas furnace 10. The already preheated HC + steam mixed gas is further heated to 800°C to 900°C in the cracked gas furnace 10, where the HC + steam mixed gas is cracked. The cracked mixed gas or cracked gas is again sent to the PQE 12 as a precooler. The process is repeated.

[0044] The exact functioning of the cracking gas furnace will not be described in detail here, since its function is well known in the prior art.

[0045] Figure 2 shows the detail of section AA in the cross-sectional view of the quencher of the quenching system, which is cooled by inducing gas on the jacket side based on the counterflow principle. The proposed TLX-G / G 14 is shown with the gas transfer line 13 placed at the gas inlet and the pipeline 19 attached to the gas outlet. In the inner tube 35 shown in section AA, the pre-cooled cracked gas or cracked product passes through the TLX-G / G 14 in a straight line from the gas transfer line 13 at the gas inlet to the pipeline 19 at the gas outlet, and is cooled in the process.

[0046] In the jacket space 30 of the TLX-G / G 14, a mixed gas consisting of HC + vapor is introduced through a gas inlet pipe 31 attached just before the outlet header at the lower end of the vertically oriented TLX-G / G, and flows while being guided by baffles 33 arranged in the jacket space of the TLX-G / G, alternately repeating every 180° around the outside of each bundle tube 36. The HC + vapor mixture leaves the TLX-G / G 14 through a gas outlet pipe 32 attached just before the inlet header at the upper end of the vertically oriented TLX-G / G.

[0047] The number of baffles 33 depends on the respective predefined load case and is determined accordingly. Due to the repeated deflection of the HC + mixed vapor, the pressure loss in the jacket space 30 is particularly high and must be minimized to ensure the efficiency of the quenching system. The tube bundles / tube sheets 37 must therefore have a particularly good arrangement, such that no bundle tubes 36 are located in the areas of the segments 34 through which the flow passes. The segments 34 without bundle tubes 36 contribute significantly to the reduction of the pressure loss and are essential for the process. The size of the segments 34 allowing free flow is between 10% and 20% of the cross-sectional area of ​​the jacket inner diameter and depends on the respective predefined load case.

[0048] Figure 3 shows a schematic arrangement of bundle tubes 36 in a tube bundle / tube sheet 37 with detail of cross section AA according to Figure 2. The arrangement of bundle tubes 36 must be particularly good to obtain high heat transfer with minimum pressure drop and no stagnation during the HC + mixed vapor flow 41. To obtain a high cooling effect, the tube arrangement is preferably configured in a triangular shape 42, the length of the sides of the triangle should be 1.2 to 1.3 times the tube outer diameter 43.

[0049] 4 shows a schematic arrangement of a compensator for the TLX-G / G quench of the quench system according to the invention. As a result of the relatively low heat transfer values, in the case of the TLX-G / G 14, the material temperature is high and the temperature difference between the bundle tubes 36 and the jacket 38 is also very large. The mechanical stresses that arise between the bundle tubes 36 and the jacket 38 due to the different thermal expansions need to be compensated. Therefore, a compensator 39 needs to be provided around the outer jacket space 30 behind the inlet header at the top end of the vertically oriented TLX-G / G 14.

[0050] FIG. 5 shows a schematic arrangement of the washing pipes in the TLX-G / G quencher of the quenching system according to FIG. 4. Due to the cooling medium consisting of HC+ vapors induced in the jacket space 30, deposits that need to be removed may also form in the TLX-G / G 14 during operation. In the case of the vertically arranged TLX-G / G 14, a closable washing pipe 40 is provided in the lower part of the jacket 38 near the outlet header in order to remove the deposits. Depending on the given level of contamination due to possible coke deposits, two to four washing pipes 40 with a diameter of 200 mm to 500 mm are provided. The washing pipes are preferably arranged near the lower tube sheet 44 of the TLX-G / G at a distance of about 100 mm to 200 mm.

[0051] Figure 6 shows the schematic arrangement of the washing pipes in the TLX-G / G quencher of the quenching system. In the case of the transversely arranged TLX-G / G 14, closable washing pipes 40 are provided along the jacket 38 to remove deposits as a result of which the cooling medium consisting of HC + vapors is guided in the lower part of the jacket space 30. Depending on the given contamination level by coke deposits, two to four washing pipes 40 with a diameter of 200 mm to 500 mm are provided.

[0052] The advantage of the quenching system using the superior TLX-G / G quench is that the cracked gas is heated in the cracked gas furnace, cracked in the process, pre-cooled in the primary quench exchanger or PQE, and then guided to the tube side of the TLX-G / G for further cooling.

[0053] Unlike conventional quenchers, the TLX-G / G does not use water / steam mixture as the jacket-side cooling medium, but a mixture of hydrocarbon gases and steam, abbreviated as HC + steam or hydrocarbon + steam. This HC + steam mixture is preheated in the TLX-G / G and simultaneously cools the cracked gases or cracked products from the cracked gas furnace, which are used in the production of ethylene and subsequently plastics. The preheated HC + steam mixture is returned to the cracked gas furnace for further heating, where it is cracked and again sent to the TLX-G / G via the PQE.

[0054] The energy required to heat the cracking gas furnace is reduced by advantageous procedures or heat recovery, which has a very positive economic and environmental impact on the whole process in terms of costs and consumption.

[0055] Using a conventional PQE as a precooler in front of the TLX-G / G allows for efficient operation of the cracking gas furnace, not only during initial operation but also during scheduling, implementation, and subsequent repairs and maintenance. [Explanation of symbols]

[0056] 10. Cracking gas furnace 11 Coil 12 Primary heat exchanger, abbreviated as PQE precooler 13 Gas Transfer Line 14 TLX-G / G as a quencher 15 HC+ steam supply line 16 HC+ steam return line 17 Supply Pipe 18 Exhaust pipe 19 Pipeline 30 Jacket Space 31 Gas inlet pipe 32 Gas outlet pipe 33 Baffle 34 Segments 35 Inner Tube 36 Vandal Tube 37 Tube vandal / tube sheet 38 Jacket 39 Compensator 40 Cleaning Pipe 41 Flow indicated by arrows 42 triangular shape 43 Tube outer diameter 44 Tube Sheet

Claims

1. A quenching system for cooling cracked gas from a cracked gas furnace using different raw materials, comprising a cracked gas furnace (10), a primary quench exchanger or PQE (12) and a secondary quench exchanger connected in series, wherein a transfer line exchanger for a cooling medium consisting of mixed gas and steam, or TLX or TLX-G / G (14) is arranged and configured as a secondary quench exchanger, and said TLX-G / G (14) is connected in series to said primary quench exchanger or PQE (12) via a gas transfer line (13) and carries said cooling medium consisting of mixed gas and steam. A supply line (15) for supplying the cooling medium is arranged in the TLX-G / G (14) at the bottom of the vertically oriented TLX-G / G before the outlet header, the TLX-G / G (14) is connected to the cracked gas furnace (10) through a return line (16) for returning the cooling medium preheated in the TLX-G / G, the TLX-G / G (14) is equipped with a pipeline (19) carrying the cracked gas cooled to a temperature range of 450°C to 300°C for further processing, and a compensator (39) is provided at the upper end of the TLX-G / G (14) behind the inlet header for the cracked gas. A rapid cooling system characterized by:

2. a gas inlet pipe (31) for the supply line (15) of the cooling medium is arranged in the jacket (38) of the TLX-G / G (14), a baffle (33) is attached in the jacket space (30) of the TLX-G / G (14), the cooling medium is guided around the outside of the bundle tubes (36) alternately every 180° during a counter-flow process around the baffle (33) of the TLX-G / G (14), a gas outlet pipe (32) for the return line (16) of the preheated cooling medium is arranged in the jacket (38) of the TLX-G / G (14) at the top end of the vertically oriented TLX-G / G before the inlet header, and a segment (34) without tube bundles (37) is provided in the jacket space (30) of the TLX-G / G (14) in the region of the baffle (33), The quenching system of claim 1 .

3. the free-flow segment (34) is sized to be between 10% and 20% of the cross-sectional area of ​​the inner diameter of the jacket (38) of the TLX-G / G (14); The quenching system of claim 2 .

4. the bundle tubes (36) of the TLX-G / G (14) are arranged in a triangular shape (42) with respect to the cooling medium flow (41), and the length of a side of the triangle is 1.2 to 1.3 times the tube outer diameter (43) of the bundle tubes (36); The quenching system of claim 2 .

5. the compensator (39) for compensating for the difference in thermal expansion between the bundle tubes (36) and the jacket (38) is installed around the jacket (38) of the TLX-G / G (14) at the upper end of the TLX-G / G and behind the cracked gas inlet header; The quenching system of claim 1 .

6. a wash pipe (40) is disposed in the region of the jacket space (30) of the TLX-G / G (14) near the tube sheet (44) of the cracked gas outlet header of the vertically oriented TLX-G / G; The quenching system of claim 1 .

7. the TLX-G / G (14) is provided in the region of the jacket space (30) with two to four closable cleaning pipes (40) each having a diameter of 200 mm to 500 mm, the cleaning pipes (40) being mounted at a distance of 100 mm to 200 mm from the lower tube sheet (44); The quenching system of claim 6 .

8. in the case of a horizontal TLX-G / G (14), two to four of said washing pipes (40) each having a diameter of 200 mm to 500 mm depending on the predetermined level of contamination by coke deposits are provided vertically in the lower region of said jacket space (30); The quenching system of claim 1 .

9. The process of a quench system for cooling cracked gas from a cracked gas furnace using different raw materials according to claim 1, comprising the cracked gas furnace (10), a primary quench exchanger or PQE (12) and a secondary quench exchanger connected in series, wherein a transfer line exchanger for a cooling medium consisting of mixed gas and steam, i.e. TLX or 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), and the transfer line exchanger for a cooling medium consisting of mixed gas and steam, i.e. TLX-G / G (14) is connected in series to the primary quench exchanger or PQE (12) via a gas transfer line (13), and the transfer line exchanger for a cooling medium consisting of mixed gas and steam, i.e. TLX-G / G (14) is arranged and configured as a secondary quench exchanger, ... the transfer line exchanger for a cooling medium consisting of mixed gas and steam, the transfer line exchanger for a cooling medium consisting of mixed gas and steam, the transfer line exchanger for a cooling medium consisting of mixed gas and steam, the transfer line exchanger for a cooling medium consisting of mixed gas and steam, the transfer line exchanger for a cooling medium consisting of mixed gas and steam, the transfer line exchanger for a cooling medium consisting of mixed gas and steam, the transfer line exchanger for a cooling medium consisting of mixed gas and steam, the transfer line exchanger for a cooling medium consisting of mixed gas and steam, a supply line (15) for conveying a cooling medium is arranged in the TLX-G / G (14) at the bottom of the vertically oriented TLX-G / G before the outlet header, the TLX-G / G (14) is connected to the cracked gas furnace (10) via a return line (16) for returning the cooling medium preheated in the TLX-G / G, the TLX-G / G (14) is equipped with a pipeline (19) carrying the cracked gas cooled to a temperature range of 450°C to 300°C for further processing, and a compensator (39) is provided at the upper end of the TLX-G / G (14) behind the inlet header for the cracked gas; The process of the quenching system is characterized by:

10. a gas inlet pipe (31) for the supply line (15) of the cooling medium is arranged in the jacket (38) of the TLX-G / G (14); a number of baffles (33) are attached in the jacket space (30) of the TLX-G / G (14), the number of the baffles being respectively dependent on and determined by a given load case; the cooling medium is guided around the outside of the bundle tubes (36) in a counter-flow process around the baffles (33) of the TLX-G / G alternately every 180°; a gas outlet pipe (32) for the return line (16) of the preheated cooling medium is arranged in the jacket (38) of the TLX-G / G (14) at the top end of the vertically oriented TLX-G / G before the inlet header; a segment (34) without tube bundles (37) is provided in the jacket space (30) of the TLX-G / G (14) in the region of the baffles (33); 10. The process of claim 9, wherein the quench system comprises:

11. the free-flow segment (34) is sized to be between 10% and 20% of the cross-sectional area of ​​the inner diameter of the jacket (38) of the TLX-G / G (14); The process of claim 10, wherein the quench system comprises:

12. the bundle tubes (36) of the TLX-G / G (14) are arranged in a triangular shape (42) with respect to the cooling medium flow (41), and the length of a side of the triangle is 1.2 to 1.3 times the tube outer diameter (43) of the bundle tubes (36); The process of claim 10, wherein the quench system comprises:

13. the compensator (39) for compensating for the difference in thermal expansion between the bundle tubes (36) and the jacket (38) is installed around the jacket (38) of the TLX-G / G (14) at the upper end of the TLX-G / G and aft of the inlet header for the cracked gas; 10. The process of claim 9, wherein the quench system comprises:

14. a wash pipe (40) is disposed in the region of the jacket space (30) of the TLX-G / G (14) near the tube sheet (44) of the cracked gas outlet header of the vertically oriented TLX-G / G; The process of claim 9, wherein the quench system comprises:

15. two to four closable cleaning pipes (40) each having a diameter of 200 mm to 500 mm are provided in the region of the jacket space (30) of the TLX-G / G (14), the cleaning pipes (40) being attached at a distance of 100 mm to 200 mm from the lower tube sheet (44) of the outlet header of the TLX-G / G; 15. The process of claim 14, wherein the quench system comprises:

16. in the case of a horizontal TLX-G / G (14), two to four of said washing pipes (40) each having a diameter of 200 mm to 500 mm depending on the predetermined contamination level by coke deposits are provided in the lower region of said jacket space (30) in a vertical orientation, 10. The process of claim 9, wherein the quench system comprises:

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