Device and method with a drain for removing liquid salt

Description

[0001] The invention relates to a device for withdrawing liquid salt, in particular for wastewater treatment plants, having a boiler room, wherein the boiler room has boiler room walls, wherein the boiler room has an inlet for introducing a saline substance, wherein the boiler room is connected to an outlet for a molten salt, wherein the outlet has an outlet channel and an outlet channel end, wherein a cooling region for cooling the molten salt is provided downstream of the outlet channel end, wherein the outlet channel is circumferentially enclosed at least along a section by an outlet wall, wherein the outlet has a heating element, wherein at least one or more of the boiler room walls have or have wall tubes, wherein the boiler room has a boiler room burner. The invention further relates to a method using such a device.

[0002] US 2 033 985 A discloses an evaporator in which water vapor is passed through the tube into the heat exchanger body and ultimately discharged via the tube. This heats the aqueous salt solution in the evaporator, causing a significant portion of the water in the solution to evaporate.

[0003] CA 2 094 571 A1 shows a heating chamber containing an aqueous salt solution. This aqueous salt solution is heated using a heat exchanger element, causing a large portion of the water content of the solution to evaporate. The heat exchanger or heating element is powered by steam.

[0004] US 3,557,864 teaches a device for incinerating saline wastewater, whereby the resulting salt mist condenses on the walls of a boiler room and is collected in a lower area of ​​the boiler room.

[0005] EP 0 340 616 A1 describes a device for purifying wastewater. A saline substance in the form of wastewater is introduced into a heating chamber where the temperature is above the melting point of the salt it contains. The water component is suddenly evaporated, while the salt component is liquefied. Due to the sudden evaporation, the water vapor entrains the liquefied salt in the form of a salt mist. In a subsequent combustion process, flammable or organic, and often environmentally harmful, compounds are broken down into their individual elements, thus resulting in purification. The salt mist condenses on the walls of the heating chamber, forming a molten salt. The molten salt then flows downwards into a basin equipped with an outlet. The outlet has an outlet channel and an outlet channel end. The molten salt falls through the outlet channel end into a movable receiving container.A hood with a fan above the end of the drain channel extracts a gas mixture that also escapes from the drain. However, this exposes the drain to a continuous air flow, which leads to the drain becoming increasingly clogged due to salt deposits and requiring regular cleaning. This process therefore requires considerable maintenance and results in low operational availability.

[0006] The invention is therefore based on the technical object of providing a device and a method for removing liquid salt that requires little maintenance and offers high operational availability. In particular, the object of the present invention is to prevent salt deposits in the area of ​​the outlet.

[0007] To achieve the technical problem, the invention teaches a device for withdrawing liquid salt, in particular for plants for purifying wastewater, with a boiler room, wherein the boiler room has boiler room walls, wherein the boiler room has an inlet for introducing a saline substance, wherein the boiler room is connected to an outlet for a molten salt, wherein the outlet has an outlet channel and an outlet channel end, wherein a cooling region for cooling the molten salt is provided downstream of the outlet channel end, wherein the outlet channel is circumferentially enclosed at least along a section by an outlet wall, wherein the outlet has a heating element, wherein at least one or more of the boiler room walls have or have wall tubes, wherein the boiler room has a boiler room burner.

[0008] Advantageously, the drain wall encloses the drain channel circumferentially along its entire length. The term "flow" refers in particular to the movement of the bulk material or a lump-bulk material mixture or solid materials. In contrast, the movement of the molten salt is preferably expressed as a "flow." For example, the heating chamber is located upstream of the drain. A conveying device is expediently located downstream of the drain. The term "drain channel" refers in particular to the cavity enclosed by the drain wall. The term "heating element" refers in particular to any structural element that serves to keep the temperature in the drain or drain channel above the melting temperature of the salt in the molten salt. For example, an air supply duct can be used as a heating element, with which hot air can be supplied to the drain channel.Induction heaters or burners can also be considered as heating elements. The heating element is preferably a burner (drain burner). It is expedient for the drain burner to extend into the drain channel in such a way that a drain burner nozzle is at least partially enclosed by the drain wall. It is advantageous if a tip of the drain burner nozzle extends into the drain channel in such a way that it is positioned above the flowing molten salt and preferably above the drain channel end or a downstream end of the drain channel or a drop opening.

[0009] The invention is based on the finding that the drain channel end is particularly problematic with regard to salt deposits. The invention is also based on the finding that air flow through the drain into the boiler room further exacerbates the problem of salt deposits at the drain channel end. It has been found that a heating element alone only solves the problem of salt deposits in specific areas, and that only the combination of a drain wall and a heating element solves the problem of salt deposits in the drain. Thus, the heat from the heating element is distributed significantly better along the drain channel if the drain channel is simultaneously enclosed by a drain wall along at least a section of the drain channel.With the help of the discharge wall, the heating element can maintain the temperature in the entire discharge channel above the melting temperature of the salt(s) in the molten salt, so that the operation of the device does not have to be interrupted for maintenance work to remove solidified salt. This fulfills the inventive objective of reducing maintenance effort and, in particular, increases the operational availability of the device.

[0010] According to a particularly preferred embodiment, the drain has a drainage channel. The drainage channel preferably comprises a metal, more preferably a steel sheet, and particularly preferably a stainless steel sheet. The drainage channel preferably extends between a wall opening in a boiler room wall and the drain channel end. The drainage channel is expediently enclosed by the drain wall at least partially and preferably completely all the way around. It is advantageous if the drainage channel is arranged within the drain channel. Expediently, the drainage channel establishes a fluidic connection for the flow of the molten salt between a wall opening in a boiler room wall and the drain channel end or the cooling region. It is preferred that the drainage channel tapers in the flow direction and preferably towards the drain channel end. It is advantageous that the drainage channel has a curved cross-section.

[0011] It is very advantageous if the drain is designed such that a heated gas emanating from the heating element can flow within the drain channel and below the molten salt flowing in the drain channel. The drain is preferably designed such that a gap or a hollow space is present between a bottom of the drain channel and the molten salt or an underside of the drain channel. It is advantageous if a support part, for example made of sheet metal, is arranged between the bottom of the drain channel and the underside of the drain channel in order to create a gap or hollow space. Preferably, a hanging part is arranged on the drain channel and fastened to a ceiling or a cover of the drain. Expediently, the support part is arranged in a region which is assigned to a more downstream half of the drain channel.It is preferred that the hanging part is located in a region of the drain associated with a more upstream half of the drain channel. It is highly preferred that the drain channel be arranged in the drain or in the drain channel such that it can be surrounded on all sides by gas heated by the heating element in cross-section, at least along a portion of the drain channel and preferably along the entire length of the drain channel. It is understood that the expression "surrounded on all sides along the entire length of the drain channel" does not exclude hanging or supporting parts.

[0012] It is particularly preferred that the drain or the drain channel or the end of the drain channel has a siphon to prevent outside air from entering the drain channel. The siphon is preferably arranged in the end of the drain channel. The drain wall expediently comprises an opening into which the siphon is inserted. The opening in the drain wall is preferably located on an underside of the drain. According to a particularly preferred embodiment, the siphon is heatable and more preferably electrically heatable. Very preferably, the siphon is heated electrically by means of induction heating. It is possible for the siphon to have an electrical resistance heater. The siphon preferably comprises an inlet area and an outlet area. Expediently, the inlet area of ​​the siphon is separated from the outlet area of ​​the siphon by a collecting basin for collecting molten salt. Advantageously, the drain channel or the drain channel orthe siphon is designed so that the molten salt flows into the inlet area of ​​the siphon and thereby fills the collection basin. The collection basin expediently comprises an overflow wall on the outlet side so that the collection basin can be filled with molten salt up to a level defined by the overflow wall. The siphon is expediently designed so that when the molten salt overflows over the overflow wall, the molten salt runs down the overflow wall and is preferably in free fall from then on. The siphon advantageously comprises a ceiling wall which, together with the collection basin or the molten salt in the collection basin, separates the inlet area from the outlet area of ​​the siphon. The ceiling wall preferably has a lower edge which is at a lower height than the upper edge of the overflow wall.The ceiling wall expediently has a submerged section defined by the height of the upper edge of the overflow wall, as well as a gas separation section located above it. The overflow wall is preferably attached at its lower end to a bottom wall of the siphon. The siphon expediently comprises an outer wall that rests against the edges of the drain opening. Expediently, the bottom wall, the outer wall, and the overflow wall form the collecting basin. The outer wall preferably encloses the ceiling wall, the overflow wall, and the bottom wall.

[0013] It is possible for the cooling area to be surrounded by a housing, with the drain or the drain channel end being connected to the housing. Preferably, the drain or the drain channel end is connected to the housing via a connecting element - in particular via a downpipe. It is preferred for the housing to enclose a / the scattering opening, a / the conveying device, a / the dividing wall and / or a / the separating device. The housing is preferably arranged below the drain or the drain channel end. The housing or the connecting element is preferably designed to enable a negative pressure in the cooling area - for example generated by a fan in the heating chamber.

[0014] According to a particularly preferred embodiment, the drain wall comprises a ceramic layer. The ceramic layer expediently has a thickness of at least 15 cm or 20 cm. It is possible for the ceramic layer to have a thickness of at most 40 cm, 35 cm or 30 cm. It is preferred for the ceramic layer to form an inner layer of the drain wall. The drain wall preferably comprises a metallic outer layer, which is made of steel, for example. The metallic outer layer has a thickness of expediently at least 3 mm / 4 mm / 5 mm and expediently of at most 12 mm / 10 mm / 8 mm. The ceramic layer of the drain wall can, for example, be bricked or integrally formed. The ceramic layer is preferably designed for temperatures of at least 800 °C / 900 °C / 1,000 °C / 1,100 °C.

[0015] It is preferred that the drain or the end of the drain channel or the drain channel has a drop opening. The term "drop opening" means in particular that from this opening onwards, the molten salt is no longer in contact with the drain or the drain channel or the drain channel and is simultaneously in a free fall. It is preferred that a main section of the drain channel tapers on its inside towards the drop opening. The taper expediently takes place in both horizontal directions. It is possible for a drop pipe to be arranged below the drop opening, wherein the drop pipe advantageously comprises a metal. The drop pipe expediently has a flange at its lower end for connection to the housing(s) for enclosing the cooling area.

[0016] The drain is advantageously arranged on a lateral boiler room wall or on an outer side of a lateral boiler room wall of the boiler room. It is advantageous if the drain protrudes with respect to the lateral boiler room wall. The drain is expediently fastened to a lower end of the lateral boiler room wall. It is within the scope of the invention for a floor of the boiler room to be sloping towards the drain. Expediently, the boiler room or the floor of the boiler room is fluidically connected to the drain or the drain channel or the drain gutter via a wall opening in the lateral boiler room wall. It is expedient if the wall opening is arranged at a height relative to the floor of the boiler room.

[0017] At least one pressure lock can be assigned to the cooling area or the housing to maintain a negative pressure in the cooling area. It is preferred that the pressure lock is designed as a rotary valve. It is expedient that the cooling area or the housing is designed such that preferably solid materials can be led out of the cooling area by means of the pressure lock or the pressure locks. It is within the scope of the invention that the housing or the cooling area is connected to at least one outlet pressure lock for a / the bulk material. It is preferred that a second outlet pressure lock is provided for lumps of solidified molten salt. It is preferred that the cooling area or the housing or the scattering opening has a rotary valve for introducing the bulk material into the housing or for scattering it onto the / a conveying device.

[0018] The drain or a cover of the drain preferably has a removable cover. When the cover is installed, the cover covers, in particular, at least partially, a / the main section or a / the drop opening of the drain channel end. When installed, the cover expediently covers at least one section, preferably a more downstream section, of a / the drain channel. It is very preferred that one or more devices are arranged on the cover. Devices can be, for example, inspection openings, heating elements, sensors, or cleaning devices. Preferably, the cover comprises a metallic outer layer, which is made, for example, of steel and preferably of sheet steel. It is preferred that the cover has a ceramic layer, preferably a ceramic inner layer. This ceramic inner layer of the cover can, for example, be bricked or integrally formed.

[0019] According to an advantageous embodiment, the drain has at least one temperature sensor and preferably two temperature sensors. The at least one temperature sensor is preferably coupled to the heating element or the drain burner, such that the at least one temperature sensor and the heating element form a control loop. The drain preferably comprises a wall temperature sensor for detecting the temperature in the drain wall and in particular in a base of the drain wall. It is preferred that the drain has a duct temperature sensor for detecting the temperature in the drain duct. The drain expediently comprises a pressure sensor for determining the gas pressure in the drain duct. It is advantageous if the duct temperature sensor and / or the pressure sensor extend through a ceiling of the drain.

[0020] It is within the scope of the invention that the drain comprises a cleaning device. The cleaning device is preferably designed so that the cleaning process is purely mechanical. It is preferred that the cleaning device has a plunger which is designed to break up or prevent salt deposits in the region of the drain channel and in particular in the region of the drain channel end. The cleaning device preferably projects through the drain wall and preferably through a ceiling of the drain wall. It is advantageous if the cleaning device is directed towards the drain channel end. The cleaning device is expediently motor-driven. Advantageously, the cleaning device is designed to push into the region of the drain channel end or the drop opening or one end of the drain channel at regular intervals.Preferably, the cleaning device is designed to detect mechanical resistance caused by more viscous molten salt when it is pushed into the area of ​​the discharge channel end or the main area or the drop opening. In the case of more viscous molten salt, the cleaning device is expediently designed to push in until the mechanical resistance is no longer detected.

[0021] It is advantageous that the drain has at least one viewing opening and preferably two viewing openings. It is preferred that the at least one viewing opening is designed such that the drain channel and in particular the drain channel end can be observed. The at least one viewing opening is preferably arranged on a ceiling of the drain wall and preferably above the drain channel end. The drain preferably comprises a second viewing opening for observing a preferably central region of the drain channel. It is expedient that the second viewing opening is arranged on a ceiling of the drain or the drain wall. A third viewing opening can be arranged on one side of the downpipe for the purpose of observing the interior of the downpipe.

[0022] The boiler room burner or the inlet for introducing the saline substance is / are oriented such that a jet of the saline substance is directed toward a combustion flame of the boiler room burner. The boiler room burner is preferably designed such that—particularly with the aid of combustible components in the saline substance—a temperature of at least 600°C / 700°C / 800°C / 900°C is reached. The boiler room burner expediently reaches a temperature of at most 1,600°C / 1,400°C / 1,200°C. It is preferred that the burner be arranged at an upstream end of the boiler room.

[0023] The boiler room walls or wall pipes are very preferably designed such that a temperature of at most 320°C / 300°C / 280°C occurs at the boiler room walls or wall. It is preferred that a temperature at the boiler room wall or walls is at least 150°C / 175°C. The wall pipes can, for example, be arranged on an outer side of the boiler room wall(s) or form the boiler room wall(s) themselves.

[0024] According to a particularly preferred embodiment, the heating chamber comprises a fan on the outlet side for extracting a gas or gas mixture from the heating chamber. Preferably, the fan or device or the heating chamber or cooling area is designed such that a negative pressure is created in the heating chamber or in the outlet or cooling area.

[0025] Very preferably, a conveyor device is arranged below the end of the discharge channel so that the molten salt can fall onto the conveyor device. The conveyor device is preferably part of the cooling area. The conveyor device expediently determines a flow direction with a preferably horizontal directional component. It is advantageous if a scattering opening for scattering the conveyor device with a bulk material is arranged upstream of the end of the discharge channel and above the conveyor device. Expediently, the device or the scattering opening or the conveyor device is designed such that the bulk material forms a bulk material bed on the conveyor device. Expediently, the bulk material or the bulk material bed on the conveyor device has a temperature such that the molten salt falling onto the bulk material bed solidifies into lumps in the bulk material bed while still on the conveyor device.Preferably, a lump-bulk material mixture outlet of a / the housing—preferably with a rotary valve—is provided downstream of the conveying device. A separating device is preferably arranged downstream of the lump-bulk material mixture outlet. The separating device is preferably designed such that the bulk material can be separated from the lumps of solidified molten salt, at least partially and preferably largely. It is preferred that a bulk material collector is arranged below the conveying device, wherein the bulk material collector is, for example, a screw conveyor. It is possible for a return conveyor line to be arranged between a downstream end of the bulk material collector and an inlet side of the scattering opening for returning the bulk material. The return conveyor line may, for example, be pneumatically operated. It is possible for the return conveyor line to have a cooling device for cooling the bulk material.Advantageously, the device comprises a bulk material silo for receiving the bulk material, wherein the bulk material silo is preferably connected to the spreading opening on the outlet side. An element for controlling / regulating the flow rate of the bulk material, preferably a rotary valve, is preferably arranged between the bulk material silo and the spreading opening. The return conveyor line is preferably arranged between the bulk material collector or housing on the one hand and the bulk material silo on the other.

[0026] To achieve the technical problem, the invention teaches a method for withdrawing liquid salt, in particular with a device according to the invention, wherein a molten salt flows along a discharge channel of a drain to a discharge channel end of the drain, wherein downstream of the discharge channel end the molten salt is cooled in a cooling region until at least it solidifies, wherein the drain has a heating element, by which the heating element - preferably when required and more preferably only when required - supplies heat to the drain or discharge channel to avoid salt deposits.

[0027] The device expediently comprises a heating chamber. It is advantageous if the heating chamber has an inlet for introducing a saline substance. It is preferred that the drainage channel be circumferentially enclosed by a drainage wall along at least one section.

[0028] It is highly preferred that the molten salt be guided along a drainage channel in the drainage channel, with the drainage channel being completely surrounded by gas heated by the heating element at least along a section of it and preferably along its entire length. It is advantageous if the drainage channel is made of a metal, preferably steel, and particularly preferably stainless steel. Due to the good thermal conductivity of metal, the circulation of heated gas quickly produces a thermal effect on the molten salt.

[0029] The invention is explained in more detail below with reference to a drawing illustrating an exemplary embodiment. The drawings show, in schematic form: Fig. 1 shows a longitudinal section through an upper part of a device according to the invention comprising a heating chamber with a drain, Fig. 2 shows a symbolic representation of a lower part of the device according to the invention, Fig. 3 shows a longitudinal section in an enlarged representation of the drain according to the invention from Fig. 1 , Fig. 4 a cross section through the drain Fig. 1 and Fig. 5 a plan view of the process of Fig. 1 , 3 and 4 .

[0030] In Fig. 1 A boiler room 1 is shown for the purification of saline substances 3 in the form of industrial wastewater. The saline substance 3 is injected into the boiler room 1 via several inlets 2 for introducing the saline substance 3. The inlets 2 are aligned such that the saline substance 3 is directed toward a combustion flame 20 of a burner 9. The saline substance 3 comprises water, salt, and combustible components. The combustible components are burned by the combustion flame 20, whereas the water component evaporates suddenly. Due to a temperature above 800°C, the salt is liquefied and, due to the sudden evaporation of the water, is entrained by the steam as salt mist.

[0031] The boiler room 1 has boiler room walls 21 with wall tubes 15 filled with steam, which keep the boiler room walls 21 at a temperature of approximately 200 to 300 °C. As a result, the salt condenses and solidifies on the inside of the boiler room walls 21, so that a salt wall 18 is formed. The salt wall 18 grows approximately 20 to 30 mm inward until the thermal insulation of the salt wall 18 is so great that the surface of the salt wall 18 remains constantly liquid. In this way, a molten salt 17 continuously flows down the salt wall 18 and collects on a slightly sloping floor 39 of the boiler room 1. At an outlet end of the boiler room 1, a fan (not shown) is arranged, which sucks away the water vapor flow, which now contains a smaller amount of salt, so that a slight negative pressure prevails within the boiler room 1.

[0032] The molten salt 17 can flow out of the boiler room 1 via an outlet 4 because a boiler room wall 21 has a wall opening 36. The outlet 4 has a drain wall 14 which defines a drain channel 19 in the form of a cavity. Arranged within the drain channel 19 is a drain channel 33 which extends from the wall opening 36 to a drain channel end 5 with a drop opening. The molten salt 17 flows from the wall opening 36 along the drain channel 33 to the drain channel end 5, in which a siphon 13 is located. The siphon 13 prevents outside air from entering the drain channel end 5, but at the same time allows the molten salt 17 to escape. In this way, a slight negative pressure also prevails in the drain 4, as in the boiler room 1, so that a constant air flow through the drain 4 into the boiler room 1 is prevented and the likelihood of salt deposits there is reduced.The molten salt 17 then falls into a lower part of the device after exiting the siphon 13.

[0033] In Fig. 2 The lower part of the device for removing liquid salt is shown symbolically. The central area of ​​the lower part is a cooling area 23, because within the cooling area 23 the molten salt 17 is cooled until it solidifies. The cooling area 23 mainly comprises a conveyor device 6. The outlet 4 is in Fig. 2 only indicated and arranged above the conveyor device 6. The conveyor device 6 in the form of an endless conveyor belt defines a flow direction which, in this embodiment, runs purely horizontally. Upstream of the discharge channel end 5, a scattering opening 7 is arranged, from which a bulk material 8, for example sand, is scattered onto the conveyor device 6. The flow velocity of the falling bulk material 8 is dimensioned such that a bulk material bed of sufficient height (for example 10 cm) forms on the conveyor device 6. For this purpose, the conveyor device 6 has two side walls (not shown) which are stationary and fix the bulk material bed. The molten salt 17 then flowing or dripping onto the bulk material bed below the discharge channel end 5 solidifies in the bulk material bed without reaching the bottom of the conveyor device 6.The molten salt 17 solidified in the bulk material bed forms lumps of solidified molten salt within the bulk material bed.

[0034] In Fig. 2 It can also be seen that a bulk material collector 12 in the form of a screw conveyor arranged below the conveyor device 6 collects bulk material 8 trickling down from the conveyor device 6. From there, this can be conveyed back to a bulk material silo 16 by means of a blower 27 via a pneumatic return conveyor line 25. Along the return conveyor line 25 there is also a cooling device 26 which, if necessary, cools the bulk material to a feed temperature. The bulk material silo 16 is connected on the outlet side to a rotary valve 24 whose speed is controllable, whereby the flow velocity of the bulk material 8 can also be adjusted. The rotary valve 24 at the outlet end of the bulk material silo 16 is assigned to the spreading opening 7 and therefore significantly determines the shape of the bulk material bed.

[0035] At the end of the conveyor 6, the lumps and the bulk material 8 fall into a separating device 10. A partition 31 prevents the lumps from falling into the bulk material collector 12. The separating device 10 of this exemplary embodiment is a slightly inclined vibrating trough with a bottom sieve, the holes of the bottom sieve being dimensioned such that the bulk material 8 falls through, but not the lumps of solidified molten salt. At the left end of the separating device 10, the lumps of solidified molten salt fall into a lump container 11, which can be, for example, a container or a big bag. The bulk material 8 falling through the separating device 10, however, is collected by a hopper and fed to the return conveyor line 25.

[0036] In Fig. 3 1 shows an enlarged longitudinal section of the drain 4. The drain wall 14 has a metallic outer layer 29, which is preferably made of sheet steel. Furthermore, the drain wall 14 comprises a heat-resistant, ceramic inner layer 28, which is, for example, 25 cm thick. The outer layer 29 made of sheet steel is, for example, 6 mm thick. The drain channel 33 leads to a main section 30 of the drain 4, which tapers towards the bottom. The drain channel 33 is supported by a hanging part 40 between a ceiling of the drain channel 19 and the drain channel 33, as well as by a support part 41 between a floor of the drain channel 19 and the drain channel 33. As a result, the drain channel 33 does not rest on the floor of the drain channel 19. As a result, gas heated by the heating element 22 can flow around the drain channel 33 from all sides. As a result, the risk of salt deposits is reduced.In addition, the drainage channel 33 can be easily replaced in case of excessive corrosion.

[0037] In Fig. 3 It can also be seen that the heating element 22 in the form of a drain burner penetrates the ceiling of the drain 4 and a nozzle of the drain burner is directed towards the drain channel end 5. Likewise, a temperature sensor 34 penetrates the ceiling of the drain 4, so that the tip of the temperature sensor 34 projects into the drain channel 19 or into the main area 30. Another temperature sensor 34 is located in a section of the drain wall 14 below the drain channel 33. This temperature sensor 34 does not penetrate the drain wall 14, so that the tip of this temperature sensor 34 detects the temperature of the drain wall 14 in the region of the bottom of the drain channel 19. The drain 4 or the ceiling of the drain 4 has a removable cover 42. Both the temperature sensor 34, which penetrates the ceiling of the drain 4, and the heating element 22 are arranged on the cover 42.In addition, two inspection openings 37 are located in the cover 42, the first inspection opening 37 being directed towards the drain channel end 5 and the second inspection opening 37 being directed towards a central section of the drain channel 33.

[0038] Fig. 3 also shows the structure of the siphon 13. The siphon 13 is located in an opening on the underside of the drain, with an outer wall 32 of the siphon resting against an inner side of the opening of the drain wall 14. A ceiling wall 44 is attached to an upper edge of the outer wall 32, the ceiling wall 44 comprising a lower immersion section 45 and an upper gas separation section 46. A bottom wall 43 is attached to a lower edge of the outer wall 32, from which an overflow wall 47 extends upwards. An upper edge of the overflow wall 47 is higher than a lower edge of the ceiling wall 44 or the immersion section 45. The molten salt 17 flows along the drain channel 33 and then falls onto the gas separation section 46 of the ceiling wall 44. From there it flows into a collecting basin of the siphon defined by the outer wall 32, the bottom wall 43 and the overflow wall 47.The collection basin of the siphon fills with the molten salt 17 until the level of the molten salt 17 in the collection basin has reached the upper edge of the overflow wall 47. The molten salt 17 then flows down the outer side of the overflow wall 47 and from there falls downwards onto the conveyor device 6. Because the lower edge of the immersion section 45 is lower than the upper edge of the overflow wall 47, and because the gas separation section 46 prevents gas or outside air from entering the discharge channel 19, it is ensured that the molten salt 17 can escape from the siphon, but outside air cannot enter the discharge channel 19. To prevent salt deposits in the siphon 13, the siphon 13 is electrically heated by means of an induction heater (not shown here).

[0039] In Fig. 4 is the process 4 from Fig. 3 shown in a cross-section, the viewing direction of this cross-section being directed away from the heating chamber walls 21. In this section, too, the heating element 22 is directed towards the drain channel end 5, so that the heating element 22, due to its arrangement directly above the drain channel end 5, penetrates the ceiling of the drain 4 or the cover 42 approximately vertically. This cross-section also shows a mechanical cleaning device 35, which is located next to the heating element 22 and is also directed towards the drain channel end 5, resulting in an arrangement that is oblique compared to the heating element 22. The cleaning device 35 is designed as a motor-operated plunger, which can prevent viscous molten salt 17 from solidifying in the region of the drain channel end 5. In addition, the cleaning device 35 is capable of detecting slight mechanical resistance caused by viscous molten salt 17.For example, once an hour, the cleaning device 35 moves into the end of the drain channel 5. If resistance is encountered, the cleaning device 35 pushes forward until the resistance is eliminated. The cleaning device 35 can be assisted by the heating element 22.

[0040] Diametrically opposite the cleaning device 35 is the Fig. 4 The first inspection opening 37 is now more clearly visible and provides a view of the drain channel end 5 or the end of the drain channel 33. This allows salt deposits or a viscous molten salt to be detected and the activities of the heating element 22 and / or the cleaning device 35 to be observed. Furthermore, this figure clearly shows that the drain channel 33 is curved in cross-section. In addition to the temperature sensor 34, a pressure sensor 38 can also be seen, which also penetrates the cover of the drain 4 or the cover 42 and is thus able to detect the gas pressure in the drain channel 19. Fig. 4 The siphon 13 is also visible. This shows the ceiling wall 44 with the immersion section 45 and the gas separation section 46. Furthermore, the upper edge of the overflow wall 47 is indicated by dashed lines due to its concealment by the ceiling wall 44.

[0041] In Fig. 5Finally, the drain 4 is depicted in a top view. This figure clearly shows how the heating element 22, the cleaning device 35, the first and second inspection openings 37, the temperature sensor 34, and the pressure sensor 38 are arranged relative to one another on the cover 42. Furthermore, it can be seen that the drainage channel 33 tapers toward the drain channel end 5 and that the siphon 13 of this exemplary embodiment has a circular cross-section. The overflow wall 47 and the immersion section 45 of the ceiling wall 44 are indicated by dashed lines.

Claims

1. Apparatus for extracting molten salt, in particular for plants for purifying waste water, with a heating chamber (1), wherein the heating chamber (1) has heating chamber walls (21), wherein the heating chamber (1) has an inlet (2) for introducing a salt-containing substance (3), wherein the heating chamber (1) is connected to an outlet (4) for a molten salt (17), wherein the outlet (4) has an outlet passage (19) and an outlet passage end (5), wherein a cooling station (23) is provided downstream of the outlet passage end (5) for cooling the molten salt (17), wherein the outlet passage (19) is peripherally enclosed along at least a section by an outlet wall (14) extending around it, wherein the outlet (4) has a heating element (22), wherein at least one or more of the heating chamber walls (21) have wall tubes (15), characterized in that the heating chamber (1) has a heating chamber burner (9).

2. Apparatus according to claim 1, wherein the outlet (4) comprises an outlet groove (33).

3. Apparatus according to claim 1 or 2, wherein the outlet (4) is designed such a way that within the outlet passage (19) and below the molten salt (17) flowing in the outlet passage (19), a heated gas emanating from the heating element (22) can flow.

4. Apparatus according to one of claims 1 to 3, wherein the outlet (4) or the outlet passage (19) or the passage end (5) has a trap (13) to prevent outside air from entering the outlet passage (19).

5. Apparatus according to one of claims 1 to 4, wherein the outlet wall (14) comprises a ceramic layer (28).

6. Apparatus according to one of claims 1 to 5, wherein the outlet passage end (5) has a drop opening.

7. Apparatus according to one of claims 1 to 6, wherein the outlet (4) is arranged on a lateral heating chamber wall (21) of the heating chamber (1).

8. Apparatus according to one of claims 1 to 7, wherein the outlet (4) has at least one viewing opening (37).

9. Apparatus according to one of claims 1 to 8, wherein the outlet (4) comprises a removable lid (42).

10. Apparatus according to one of claims 1 to 9, wherein the outlet (4) has at least one temperature sensor (34).

11. Apparatus according to one of claims 1 to 10, wherein the outlet (4) comprises a cleaning device (35).

12. Apparatus according to one of claims 1 to 11, wherein a conveyor device (6) is arranged below the outlet passage end (5) so that the molten salt (17) can fall onto the conveyor device (6).

13. Method for removing molten salt using an apparatus according to any one of claims 1 to 12, wherein molten salt (17) flows along an outlet passage (19) of an outlet (4) to an outlet passage end (5) of the outlet (4), wherein the outlet (4) is connected to a heating chamber (1), wherein the heating chamber (1) has heating chamber walls (21), wherein downstream of the outlet passage end (5) the molten salt (17) is cooled in a cooling station (23) to at least solidification, wherein the outlet (4) has a heating element (22), wherein the heating element (22) supplies heat to the outlet passage (19) to prevent salt deposits, wherein at least one or more of the heating chamber walls (21) have wall tubes (15).

14. Method according to claim 13, wherein the molten salt (17) is guided in the outlet passage (19) along an outlet groove (33), wherein the outlet groove (33) is completely surrounded, at least along a section, by a gas heated by the heating element (22).