Synthesis gas cooler for the industrial production of ammonia

Abstract

The invention relates to a synthesis gas cooler (10) for cooling a synthesis gas for the industrial production of ammonia, comprising: a container (12), wherein the container (12) has an inlet (14) for supplying hot synthesis gas (16) and an outlet (18) for discharging cooled synthesis gas (22); a heat exchanger (24) provided in the container (12), for cooling the hot synthesis gas (16); a bypass line (34) for guiding a portion of the hot synthesis gas (16) past the heat exchanger (24); and a separating wall (32) provided in the container (12), for delimiting a mixing chamber (20). In order in particular to prevent damage caused by metal dusting, a protective volume is provided in the synthesis gas cooler (10), and the bypass line (34) runs through the protective volume (42) in such as way as to fluidically communicate with the mixing chamber (20).

Description

[0001] Synthesis gas cooler for the industrial production of ammonia

[0002] Description

[0003] The invention relates to a synthesis gas cooler with which synthesis gas can be cooled for the industrial production of ammonia, and to a method for operating such a synthesis gas cooler.

[0004] From EP 3 262 363 Bl, a synthesis gas cooler for cooling synthesis gas for the industrial production of ammonia is known, in which the supplied synthesis gas is divided after passing through a first heat exchanger into a first partial flow, which passes through a second heat exchanger and a second partial flow, which is routed past the second heat exchanger via a bypass line formed outside the rest of the synthesis gas cooler and is mixed back into the first partial flow in a mixing chamber at the outlet of the second heat exchanger in order to be able to set a desired outlet temperature at the outlet of the synthesis gas cooler.

[0005] From DE 39 13 422 Al a shell and tube heat exchanger is known which has a bypass line centrally routed through a package of heat exchanger tubes, wherein a flow rate of a gas to be cooled is divided between the heat exchanger tubes and the bypass line by means of control valves at a transition to a mixing chamber in order to be able to set a desired outlet temperature at the outlet of the shell and tube heat exchanger.

[0006] There is a constant need to prevent malfunctions of a synthesis gas cooler, even under extreme operating conditions. The object of the invention is to provide measures that enable the fail-safe operation of a synthesis gas cooler.

[0007] The problem is solved by a synthesis gas cooler having the features of claim 1 and a method having the features of claim 9. Preferred embodiments are specified in the dependent claims and the following description, each of which, individually or in combination, may represent an aspect of the invention. Where a feature is presented in combination with another feature, this serves only to simplify the presentation of the invention and is in no way intended to imply that this feature cannot also be a further development of the invention without the other feature, the scope of protection of the invention being defined by the independent claims.

[0008] One aspect of the invention relates to a synthesis gas cooler for cooling synthesis gas for the industrial production of ammonia, comprising a container, wherein the container has an inlet for supplying hot synthesis gas and an outlet for removing cooled synthesis gas, a heat exchanger provided in the container for cooling the hot synthesis gas, a bypass line for diverting a portion of the hot synthesis gas past the heat exchanger, a partition provided in the container for separating a mixing chamber, in particular adjoining the outlet, and a [missing information] axially to the partition (i.e.,a protective wall offset in the longitudinal direction of the container of the synthesis gas cooler), wherein a protective volume protected against the ingress of synthesis gas is enclosed between the protective wall, the partition wall and the container, and at least one through-line for conveying cold synthesis gas cooled in the heat exchanger into the mixing chamber, wherein the bypass line is fluidically communicating with the mixing chamber through the protective volume and an actuator provided in the protective volume for varying a flow rate in the bypass line and / or in the through-line.

[0009] In the industrial production of ammonia (NH3), synthesis gas can first be generated from hydrocarbons, particularly natural gas. For this purpose, natural gas, especially methane, can be converted into synthesis gas energy-efficiently using autothermal reforming (ATR) with oxygen and steam at high temperature and high pressure. The heat required to break down the methane molecules is generated by the exothermic oxygen reaction that takes place during this process. In a subsequent process step, the hydrogen required for ammonia production can be obtained from the synthesis gas, particularly using the water-gas shift reaction. The carbon dioxide (CO2) produced during hydrogen production should be captured as completely as possible, preferably by more than 90% by weight, to prevent the CO2 from escaping into the atmosphere and instead store it in a climate-friendly manner, for example, by capturing it underground.The ammonia produced in this way is also known as "blue ammonia." The water-gas shift reaction can, in particular, initially be carried out at a high temperature ("HT shift") to achieve rapid reaction kinetics, and subsequently at a low temperature ("LT shift") to shift the reaction equilibrium towards the reactant side with CO2 and H2. Since the HT shift also occurs at a lower temperature compared to autothermal reforming, it is necessary to cool the synthesis gas produced in autothermal reforming to the temperature required for the water-gas shift reaction in the synthesis gas cooler.

[0010] To facilitate CO2 separation, synthesis gas is produced at a higher temperature and pressure compared to conventional ammonia production ("grey ammonia"). This leads to a risk of high-temperature corrosion ("metal dusting") for the components in the mixing chamber and the outlet area of ​​the synthesis gas cooler.

[0011] Fouling and / or clogging of the heat exchanger tubes during operation leads to a deterioration in heat transfer ("fouling") in the heat exchanger over time. This results in better cooling performance and thus a lower temperature of the cooled synthesis gas at the beginning of the synthesis gas cooler's service life than later on. The deposits causing the fouling can originate from the upstream process path. These deposits consist largely of components carried away from the internal thermal insulation of the components (refractory lining / e.g., SiO2). Other possible sources of deposits include general contamination in the pipelines (dust, etc.) and partial carryover from the catalysts.

[0012] The decreasing cooling capacity of the heat exchanger over time due to fouling leads to an increasing temperature of the cooled synthesis gas. Therefore, counteracting this by changing the synthesis gas flow rate through the bypass line is necessary to maintain the synthesis gas outlet temperature at a desired constant temperature.

[0013] The actuators allow the flow rate in the bypass line and the main line to be varied, thereby changing the amount of hot, uncooled synthesis gas from the bypass line and cold, heat exchanger-cooled synthesis gas from the main line entering the mixing chamber. Depending on the mixing ratio of the two quantities and their temperatures, a mixing temperature is established in the mixing chamber at which the synthesis gas, cooled in the synthesis gas cooler, can leave the synthesis gas cooler via the outlet.If the heat transfer in the heat exchanger tubes deteriorates due to deposits, fouling, and the like (fouling), and thus the cooling capacity decreases, the actuator can be used to reduce the amount of (hot) synthesis gas flowing through the bypass line and increase the amount of (cold) synthesis gas flowing through the heat exchanger in order to maintain a desired target temperature for the synthesis gas at the outlet of the synthesis gas cooler. However, this necessitates that the actuator, which includes moving mechanical parts, be located inside the vessel to vary the flow rate within the bypass line and the main supply line.

[0014] The invention utilizes the finding that a partition wall can advantageously be provided for the formation of the mixing chamber in order to cost-effectively and easily separate the volume of the mixing chamber from the remaining volume of the container. The partition wall is penetrated by the supply of the synthesis gas cooled in the heat exchanger and the supply of the hot synthesis gas from the bypass line. The protective wall, which is slightly offset axially from the partition wall and is preferably identical in design to the partition wall, can also be penetrated analogously. This results in a protective volume being formed in the axial space between the partition wall and the protective wall. This protective volume, however, does not communicate fluidically with the remaining volume of the container and is preferably sealed against the ingress of synthesis gas from the remaining volume of the container.Since the synthesis gas cannot penetrate the protective volume, an atmosphere free of synthesis gas is maintained within the protective volume. The actuator located in this synthesis gas-free atmosphere of the protective volume therefore does not come into contact with the carbon-containing synthesis gas. Because contact between the actuator and the carbon-containing atmosphere of the synthesis gas is thus avoided, carbon deposition on the surface of the actuator can be prevented, effectively preventing metal dusting even when the temperature of the protective volume and / or the actuator is in a range critical for metal dusting, particularly between 450°C and 800°C.Although the actuator inside the container is exposed to a temperature range critical for metal dusting, the fluidic separation of the syngas from the protective volume prevents an atmosphere at the actuator that would be necessary for metal dusting, thus reliably avoiding any impairment of the actuator's functionality due to metal dusting and enabling fail-safe operation of the syngas cooler even under extreme operating conditions.

[0015] The synthesis gas cooler is designed for industrial ammonia production. Specifically, the synthesis gas cooler is dimensioned for ammonia production exceeding 3000 t / day, and particularly over 3500 t / day, and has correspondingly large dimensions.

[0016] The vessel of the synthesis gas cooler can be cylindrical. For example, the vessel has a cylindrical, particularly circular, central section, to the axial ends of which dome-shaped, particularly spherical, hoods are attached. Cylindrical coordinates used, particularly axial and radial directions, refer to the central section and / or a centerline of the central section. The centerline of the vessel can be vertical or, preferably, horizontally oriented. The vessel, and in particular the respective hood of the vessel, can form the inlet and outlet for the synthesis gas. The central section can have through-openings for the passage of a coolant for the heat exchanger provided within the vessel.

[0017] The heat exchanger can, in particular, have heat exchanger tubes extending axially along the vessel, which penetrate a cooling jacket of the heat exchanger in the axial direction. The cooling jacket is permeable to the coolant, allowing the coolant to absorb heat at an outer surface of the heat exchanger tubes and dissipate it convectively. The cooling jacket is typically a continuous cylinder without any free space. The bypass flow also penetrates the cooling jacket in the axial direction, parallel to the tubes.

[0018] The bypass line is located entirely within the vessel, thus preventing convective heat dissipation to the environment. To prevent heat transfer from the bypass line to the coolant, the bypass line is insulated. This design takes advantage of the fact that the bypass line itself is intentionally not cooled; rather, the synthesis gas introduced into the mixing chamber via the bypass line should ideally have the same temperature as the synthesis gas at the inlet of the synthesis gas cooler. This allows the heat exchanger to be deliberately dimensioned for a cooling capacity that is initially higher than necessary ("SOR": start of run), ensuring that even with advanced fouling and significantly reduced heat transfer towards the end of operation ("EOR": end of run), sufficient cooling of the synthesis gas can still be achieved.Since, in the SOR process, the hot synthesis gas can be routed around the heat exchanger tubes via the bypass line to a correspondingly large extent in order to avoid excessive cooling and to achieve the desired target temperature at the outlet of the synthesis gas cooler, it is possible to design the heat exchanger only for the EOR process and an associated desired operating time.

[0019] The partition and / or the protective wall can be attached to the container in a radial direction, for example, by welding. The attachment of the partition and / or the protective wall can be fluid-tight, preventing the synthesis gas from passing through. It is also possible to attach the at least one through-line and the bypass line fluid-tight in through-openings in the partition and / or the protective wall, in particular by welding. The actuator is located at least largely, and preferably entirely, within the protective volume. An actuator operated by the actuator, for example, a sliding valve body or a rotatable flap, can be located within the bypass line or within the through-line and exposed to the synthesis gas.The actuator can, however, be actuated by the actuator through the respective line, in particular mechanically, electrically, magnetically and / or electromagnetically. In particular, a mechanical coupling between the actuator and the actuator is sufficiently sealed through the material of the bypass line or the through-line, so that a thermally robust, purely mechanical actuator can be implemented.

[0020] In particular, a bypass valve, designed in particular as a rotatable bypass flap, and actuated by the actuator, is provided in a common axial area with the protective volume in the bypass line to change the flow rate in the bypass line, and / or a through-flow valve, designed in particular as a rotatable through-flow flap, and actuated by the actuator to change the flow rate in the through-flow line. The respective valve can penetrate the associated line in a radial direction to be actuated by the actuator. The associated penetration can be sufficiently sealed so that no synthesis gas can enter the protective volume. This avoids the need for the actuator to penetrate the partition or the protective wall to actuate the associated valve. The entire actuator can also be completely enclosed within the protective volume to actuate the respective valve.In particular, a rotatable axis of rotation for the respective flap is guided through the associated pipe into the protective volume, so that the actuator can apply a torque to the axis of rotation within the protective volume to rotate the associated flap and thus change the flow rate. Preferably, the pipe and / or the bypass valve and / or the flow valve and / or the components of the actuator are made of a high-temperature corrosion-resistant material, wherein the high-temperature corrosion-resistant material is, in particular, a nickel-chromium-aluminum alloy, preferably Alloy 699XA. This prevents metal dusting in the area of ​​the valves actuated by the actuator and in the pipe.Since only a small proportion of the materials used are made of high-temperature corrosion-resistant material compared to the heat exchanger tubes of the heat exchanger, the manufacturing costs for the synthesis gas cooler can be kept low.

[0021] The actuator particularly preferably comprises a rotatable actuating rod that penetrates the container substantially in a radial direction, wherein the actuating rod is designed to vary the flow rate in the bypass line and / or in the through-line when rotated. Since the actuating rod extends radially, it can penetrate the container within the common axial area with the protective volume and be rotated outside the container, particularly by an electric motor. This allows the drive mechanism for the actuator to be located in a thermally stressed area. The actuating rod can be robust against thermal influences and easily transmit an actuating force to the valves. The rotatable actuating rod can easily provide a suitable leverage force for actuating the respective valve via projecting links.In principle, it is possible to vary the flow rate for each valve separately using a separate adjusting rod.

[0022] In particular, the system provides for exactly one actuating rod, designed to simultaneously and in a positively coupled manner vary the flow rate in both the bypass line and the main line. The actuator can thus, for example, open the main line proportionally to closing the bypass line, or vice versa. This ensures, with minimal design effort, that all lines are not unintentionally closed simultaneously, preventing an operational malfunction.

[0023] Preferably, a temperature sensor is provided for detecting the temperature of the synthesis gas in the mixing chamber. The temperature sensor is connected to a control unit for operating the actuator, and the control unit is configured to regulate a target temperature of the synthesis gas in the mixing chamber by varying the flow rate in the bypass line and the main line. With the aid of the actuator, the control unit can achieve temperature control of the synthesis gas at the outlet of the synthesis gas cooler, so that the synthesis gas can be fed to a subsequent process step, in particular a water-gas shift reaction, at a precisely defined target temperature.

[0024] The bypass line, particularly in the area of ​​the mixing chamber, preferably has a thermally insulating sheath, wherein the sheath is dimensioned to maintain the wall temperature of the bypass line at a temperature above 800°C, particularly above 850°C. The bypass line can, for example, have an inner pipe and an outer pipe arranged substantially coaxially to the inner pipe, between which a thermal insulating material and / or an enclosed gas or vacuum is provided. This utilizes the fact that, particularly in the production of blue ammonia, the synthesis gas supplied via the inlet can have a particularly high temperature, which can even exceed a temperature range relevant for the formation of metal dusting. The thermally insulating sheath of the bypass line ensures that the synthesis gas in the bypass line and the material or...The wall temperature of the bypass line is so high that, due to the very high temperature of the synthesis gas and the material / wall temperature of the bypass line, metal dusting in and on the bypass line can be avoided without the need to use a high-temperature corrosion-resistant material such as Alloy 699XA for the bypass line.

[0025] This allows metal dusting of the bypass line to be avoided with the help of a very cost-effective measure by taking advantage of the special operating conditions.

[0026] In particular, a surface facing or in contact with the synthesis gas has a sacrificial layer for decomposition by high-temperature corrosion with a layer thickness s of s > 1.5 mm, particularly s > 2.0 mm, and preferably s > 2.5 mm, wherein the surface is part of the vessel and / or the partition and / or the protective wall and / or the feed line and / or the heat exchanger. Surfaces exposed to the synthesis gas that would be susceptible to metal dusting during operation can be provided with a sacrificial layer designed for the desired service life, the layer thickness of which allows metal dusting without impairing the functionality of the respective surface. The sacrificial layer to be sacrificed for metal dusting can be integrally formed with the rest of the material.

[0027] A further aspect of the invention relates to a method for operating a synthesis gas cooler, which can be designed and further developed as described above, in the industrial production of ammonia, in particular blue ammonia, in which a hot synthesis gas with a temperature of at least 800°C, in particular at least 850°C, is supplied to the synthesis gas cooler, wherein the synthesis gas cooler is operated in a pressure range of 50–100 bar, and wherein the hot synthesis gas is distributed between the heat exchanger and the bypass line such that a predetermined target temperature is achieved in the mixing chamber, with the synthesis gas being routed past the protective volume. The method can be designed and further developed, in particular as explained above, using the synthesis gas cooler as an example.Although the actuator inside the container is exposed to a temperature range critical for metal dusting, the fluid separation of the syngas from the protective volume prevents an atmosphere at the actuator that would be necessary for metal dusting, thus reliably avoiding any impairment of the actuator's functionality due to metal dusting and enabling fail-safe operation of the syngas cooler even under extreme operating conditions.

[0028] Preferably, during the operating period of the synthesis gas cooler, between the start of operation and the end of operation, the flow rate through the bypass line is reduced such that a predetermined target temperature is maintained in the mixing chamber at all times. Before the synthesis gas can no longer be cooled to the desired target temperature due to fouling in the heat exchanger, even with complete closure of the bypass line by means of the actuator, the operation of the synthesis gas cooler is terminated. This allows the fouling to be repaired, for example, by replacing the heat exchanger and, if necessary, other components affected by metal dusting during an overhaul of the synthesis gas cooler. In particular, the actuator, protected within the protective volume, can be reused for subsequent operation of the repaired synthesis gas cooler.

[0029] The synthesis gas cooler is preferably operated in a plant for the industrial production of so-called blue ammonia. In such plants, the risk of metal dusting is greater than in gray ammonia plants (i.e., those in which the synthesis gas is produced entirely from natural gas (e.g., by steam reforming)). The risk of metal dusting is particularly increased in industrial ammonia production plants that include an autothermal reformer (ATR), making the synthesis gas cooler and operating method according to the invention especially suitable for use in plants with ATR technology.

[0030] The invention is explained below by way of example with reference to the accompanying drawings and preferred embodiments, wherein the features shown below can represent an aspect of the invention both individually and in combination. If, in a specific embodiment, a feature is shown in combination with another feature, this serves only to simplify the presentation of the invention with reference to that embodiment and is in no way intended to imply that this feature cannot also be a further development of the invention without the other feature, wherein the scope of protection of the invention is defined by the independent claims. The drawings show:

[0031] Fig. 1: a schematic cutaway side view of a synthesis gas cooler, Fig. 2: a schematic perspective view of part of the synthesis gas cooler from Fig. 1 and

[0032] Fig. 3: a schematic cutaway detail view of part of the synthesis gas cooler from Fig. 1.

[0033] The synthesis gas cooler 10 shown in Fig. 1 can be used, in particular, in a plant for the production of so-called blue ammonia, wherein the synthesis gas cooler 10 is preferably dimensioned for ammonia production of over 3000 t / day, in particular over 3500 t / day. The synthesis gas cooler 10 has a roughly cylindrical container 12, which is preferably oriented horizontally. Hot synthesis gas 16 can be supplied at an inlet 14, adjusted to a desired target temperature in a mixing chamber 20, and discharged as mixed, cooled synthesis gas 22 via an outlet 18. An annular heat exchanger 24 is provided inside the container 12, which has heat exchanger tubes 26 running axially through the container 12 and which can be cooled by a coolant 28.In the illustrated embodiment, the coolant 28 flows radially, in particular against the direction of gravity, through the housing 12 and the heat exchanger. Suitable passages for the coolant 28 are provided in the housing 12. A closable manhole 30 can also be provided so that the interior of the container 12 can be accessed by a person for maintenance and repair work.

[0034] The mixing chamber 20 is bounded on one axial side by the container 12 with the outlet 18 and on another axial side by a partition 32. The partition 32 is penetrated by a bypass line 34 that passes centrally through the heat exchanger 24, allowing a portion of hot synthesis gas 16 to enter the mixing chamber 20 almost uncooled. The cold synthesis gas 36, cooled in the heat exchanger 24, can be fed into the mixing chamber 20 through the partition 32 via separate feed lines 38. A protective wall 40 is attached to or connected to the container 12 (e.g., by a material bond, in particular by welding) at a distance from the partition 32, creating a defined protective volume 42 in the axial area between the partition 32 and the protective wall 40. Within the protective volume, the exchange of substances between the surfaces of the components that define the protective volume is prevented.the components arranged in the protective volume and the gas contained in the protective volume are reduced to such an extent that metal dusting is effectively prevented.

[0035] Both the bypass line 34 and the through-lines 38 also pass through the protective wall 40, so that no synthesis gas 16, 36 can enter the protective volume 42. Within the protective volume 42, an actuator 44 is provided for varying the flow rate in the bypass line 34 and in the through-line 38, or in the two through-lines 38 shown. For the sake of simplicity, in Fig. 1, one of the actuators 44 is shown outside the protective volume 42, deviating from the actual arrangement.

[0036] The actuating mechanism 44, shown in detail in Fig. 2, can penetrate the container 12 at at least one point, for example to rotate an actuating rod 46. The rotatable actuating rod 46 can vary the flow rate in the bypass line 34 and in the through-line 38 via linkage levers 48, for example by adjusting a through-line valve 50 in the through-line 38 and / or a bypass valve 50 in the bypass line 34, preferably positively coupled to each other. The actuating mechanism 44 is actuated by an actuator 60 (see Fig. 3), for example by rotating the actuating rod 46 about its longitudinal axis by means of the actuator 60. For the sake of simplicity, the protective wall 40, which would otherwise be visible, is not shown in Fig. 2 in order to allow a view of the interior of the protective volume 42.

[0037] As shown in Fig. 3, the bypass line 34 can be provided with a thermally insulating sheath 52, which protects the material of the bypass line 34 from cooling and allows the wall temperature of the bypass line 34 to be maintained at a temperature above 800 °C. This makes it possible to keep the wall temperature of the bypass line at a temperature too high to cause metal dusting in the bypass line 34. For example, the temperature of the hot synthesis gas 16 in the bypass line 34 is approximately 1005 °C ± 20 K. However, the actuator 44 enclosed in the protective volume 42 is protected from mass transfer with the synthesis gas 16, 36, so that even in a temperature range within the protective volume 42 that is critical for metal dusting, metal dusting at the actuator 44 is not a concern.

[0038] The wall temperature of the heat exchanger tubes 26 is not critical with regard to the risk of metal dusting; that is, the heat exchanger tubes are not at risk of being attacked by metal dusting. Due to the strong cooling effect of the coolant, the wall temperature of the heat exchanger tubes 26 always remains well below 450°C. Metal dusting is a concern for the components located in the mixing chamber 20 and the protective volume 42. Without insulation of the bypass line 34 in the area of ​​the mixing chamber 20 and the protective volume 42, heat exchange would occur between the cold synthesis gas 36 and the bypass line 34. This would result in a wall temperature of the bypass line 34 (outer surface) that falls within the range where metal dusting occurs. Due to the insulating sheathing 52, this heat transfer is inhibited, and the bypass line 34 has a wall temperature of >800°C or even the synthesis gas temperature.Furthermore, the insulating sheathing 52 inhibits the mass exchange between bypass line 34 (outside) and the cold synthesis gas 36, which also significantly reduces the metal dusting risk.

Claims

P a t e n t a n s p r ü c h e 1. Synthesis gas cooler (10) for cooling synthesis gas for the industrial production of ammonia, comprising a container (12) wherein the container (12) has an inlet (14) for supplying hot synthesis gas (16) and an outlet (18) for removing cooled synthesis gas (22), a heat exchanger (24) provided in the container (12) for cooling the hot synthesis gas (16), a bypass line (34) for diverting a portion of the hot synthesis gas (16) past the heat exchanger (24), and a partition (32) provided in the container (12) for separating a mixing chamber (20), characterized by a protective wall (40) axially offset from the partition (32), wherein a protective volume (42) protected against the ingress of synthesis gas is enclosed between the protective wall (40), the partition (32), and the container (12).and at least one through-line (38) passing through the protective volume (42) for conveying cold synthesis gas (36) cooled in the heat exchanger into the mixing chamber (20), wherein the bypass line (34) is fluidically communicating with the mixing chamber (20) through the protective volume (42) and an actuator (44) provided in the protective volume (42) for varying a flow rate in the bypass line (34) and in the through-line (38).

2. Synthesis gas cooler (10) according to claim 1, wherein in a common axial area with the protective volume (42) in the bypass line (34) a bypass valve actuated by the actuator (44) for changing a flow rate in the A bypass line (34) and / or a through-flow valve that can be actuated by the actuator (44) is provided to change the flow rate in the through-flow line (38).

3. Synthesis gas cooler (10) according to claim 1 or 2, wherein the feed line (38) and / or the bypass valve and / or the feed valve and / or the components of the actuator (44) are made of a high-temperature corrosion-resistant material, wherein in particular the high-temperature corrosion-resistant material is a nickel-chromium-aluminium alloy, preferably Alloy 699XA.

4. Synthesis gas cooler (10) according to one of claims 1 to 3, wherein the actuating mechanism (44) has a rotatable actuating rod (46) penetrating the container (12) substantially in a radial direction, wherein the actuating rod (46) is designed to vary the flow in the bypass line (34) and / or in the through-line (38) when rotated.

5. Synthesis gas cooler (10) according to claim 4, wherein exactly one adjusting rod (46) is provided and the adjusting rod (46) is designed to simultaneously and in a positively coupled manner vary the flow rate in both the bypass line (34) and the through line (38).

6. Synthesis gas cooler (10) according to claim 4 or 5, wherein a temperature sensor is provided for detecting the temperature of the synthesis gas in the mixing chamber (20), wherein the temperature sensor is connected to a control device for operating the actuator (44) and the control device is configured to regulate a target temperature of the synthesis gas in the mixing chamber (20) by varying the flow rate in the bypass line (34) and / or in the through-line (38).

7. Synthesis gas cooler (10) according to one of claims 1 to 6, wherein the bypass line (34) has a thermally insulating sheathing (52), wherein the sheathing (52) is dimensioned to maintain the wall temperature of the bypass line (34) at a temperature above 800°C, in particular above 850°C.

8. Synthesis gas cooler (10) according to one of claims 1 to 7, wherein a surface facing the synthesis gas has a sacrificial layer for decomposition by high-temperature corrosion with a layer thickness s of s > 1.5 mm, in particular s > 2.0 mm and preferably s > 2.5 mm, wherein the surface is part of the container (12) and / or the partition (32) and / or the protective wall (40) and / or the through-line (38) and / or the heat exchanger (24).

9. Method for operating a synthesis gas cooler (10) according to one of claims 1 to 8 in the industrial production of ammonia, in which a hot synthesis gas (16) at a temperature of at least 800°C, in particular at least 850°C, is supplied to the synthesis gas cooler (10), wherein the synthesis gas cooler (10) is operated in a pressure range of 50 - 100 bara, and wherein the hot synthesis gas (16) is divided between the heat exchanger (24) and the bypass line (34) such that a predetermined target temperature is achieved in the mixing chamber (20), wherein the synthesis gas is passed by the protective volume (42).

10. Method according to claim 9, wherein, over an operating period of the synthesis gas cooler (10) between a start-of-run and an end-of-run, the flow through the bypass line (34) is reduced such that a predetermined target temperature is always maintained in the mixing chamber (20) during the operating period.

11. A method according to claim 9 or 10, wherein the synthesis gas cooler (10) is operated in a plant for the industrial production of so-called blue ammonia.

12. A method according to any one of claims 9 to 11, wherein the plant for the industrial production of so-called blue ammonia is operated in a plant for the industrial production of so-called blue ammonia. The production of ammonia includes an autothermal reformer (ATR).

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