Steam preheating system, steam preheater and garbage incinerator

Abstract

Disclosed in the present invention is a steam preheating system. The steam preheating system comprises at least one steam heating unit having a condensation section, a subcooling section and a liquid level tank, wherein the condensation section is configured to introduce steam, a liquid discharge port of the condensation section being in communication with the subcooling section by means of the liquid level tank; the liquid level tank is in communication with a steam introduction port of the condensation section by means of a steam balance pipe, condensate water drained from the condensation section through the liquid discharge port flowing into the liquid level tank by means of the gravity of the condensate water; the subcooling section is connected to a drain pipe configured to output the condensate water and provided with a drain regulation valve; and the opening degree of the drain regulation valve is controlled according to a liquid level signal of the liquid level tank. The steam preheating system uses a steam heating unit to heat a medium to be heated, and drained water in a condensation section into which high-pressure steam has been introduced is input into a subcooling section by means of a liquid level tank to exchange heat with said medium again in order that the temperature of the drained water reaches a certain subcooling, thus reducing the intensity of flash evaporation occurring in the drained water after the drain regulation valve in the drain pipe connected to the subcooling section, and being conducive to prolonging the service life of the drain pipe. Further disclosed in the present invention are a steam preheater and a garbage incinerator.

Description

Steam preheating system, steam preheater and waste incinerator

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 29, 2023, with application number 202310789343.X and invention name “Steam Preheating System, Steam Preheater and Waste Incinerator”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of mechanical industry, and more particularly to a steam preheating system, and also includes a boiler using the steam preheater. Background Art

[0003] Waste incinerators are equipped with air heating facilities, which usually use steam preheaters arranged outside the boiler to heat the air. Currently, the steam-air preheaters in waste-to-energy plants use high-pressure steam, medium-pressure steam, and low-pressure steam to heat the air, achieving different levels of energy utilization. However, the water condensed from the high-pressure steam is generally discharged through a drain pipe, and a drain valve is installed on the drain pipe to regulate the flow. However, the temperature of the water in the drain pipe is mostly the saturation temperature corresponding to the steam pressure, and the pressure behind the drain valve will drop significantly. The corresponding saturation temperature drops, and the drain will undergo violent vaporization, generating a large amount of flash steam. The flash steam will flush the drain pipe, causing significant damage to the drain pipe and seriously affecting its service life.

[0004] Therefore, how to reduce the degree of damage to the drain pipe caused by flash evaporation of condensed water of high-pressure steam in the drain pipe and increase the service life of the drain pipe is an urgent problem to be solved by those skilled in the art.

[0005] Summary of the Invention

[0006] In light of this, the present invention provides a steam preheating system that utilizes a steam heating unit with a condensing section and a subcooling section to heat the medium to be heated. After the introduction of high-pressure steam, drain water from the condensing section is fed through a liquid level tank into the subcooling section for further heat exchange with the medium to be heated, thereby achieving a certain degree of subcooling. This reduces the severity of flash evaporation of the drain water after the drain regulating valve in the drain pipe connected to the subcooling section, reduces damage to the drain pipe, and improves the service life of the drain pipe. The present invention also provides a steam preheater and a waste incinerator utilizing the above-described steam preheating system, which helps protect the drain pipe of the steam preheater and improves its service life.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A steam preheating system comprises at least one steam heating unit for heating a medium to be heated by utilizing steam; the steam heating unit comprises a condensing section, a subcooling section and a liquid level tank; the condensing section is used for introducing steam, and the drain port of the condensing section is connected to the subcooling section via the liquid level tank; the liquid level tank is connected to the steam inlet of the condensing section via a steam balance pipe, and condensed water discharged from the drain port in the condensing section flows into the liquid level tank by its own gravity; the subcooling section is connected to a drain pipe for outputting condensed water, and a drain regulating valve is provided on the drain pipe; the opening of the drain regulating valve is controlled according to the liquid level signal of the liquid level tank.

[0009] Optionally, in the above-mentioned steam preheating system, the opening of the steam trap regulating valve is controlled by a controller; a liquid level gauge is provided in the liquid level tank, and the liquid level gauge is connected to the controller signal.

[0010] Optionally, in the above steam preheating system, there are multiple steam heating units, and each steam heating unit utilizes a different steam pressure level.

[0011] Optionally, in the above-mentioned steam preheating system, the steam heating units are arranged one by one, and along the arrangement direction, the pressure level of the steam used by each steam heating unit gradually decreases or gradually increases.

[0012] Optionally, in the above-mentioned steam preheating system, in any two adjacent steam heating units, the condensate discharged from the supercooling section of the steam heating unit with a higher steam pressure level is transported to the liquid level tank of the steam heating unit with a lower steam pressure level through the drain pipe connected to the supercooling section.

[0013] Optionally, in the above-mentioned steam preheating system, among all the steam heating units, the subcooling section of the steam heating unit with the lowest steam pressure level is connected to the drain tank or deaerator through the drain pipe connected to the subcooling section.

[0014] Optionally, in the above steam preheating system, there are three steam heating units, and the condensation sections of the three are used to introduce high-pressure steam, medium-pressure steam and low-pressure steam respectively.

[0015] Optionally, in the above steam preheating system, the medium to be heated is wind for input into the boiler.

[0016] A steam preheater comprises a steam preheating system, wherein the steam preheating system is the steam preheating system described in any one of the above technical solutions.

[0017] A garbage incinerator comprises a steam preheater, wherein the steam preheater is the steam preheater provided by the above technical solution.

[0018] The present invention provides a steam preheating system, comprising at least one steam heating unit for heating a medium to be heated by utilizing steam; the steam heating unit comprises a condensing section, a subcooling section and a liquid level tank; the condensing section is used for introducing steam, and the drain port of the condensing section is connected to the subcooling section via the liquid level tank; the liquid level tank is connected to the steam introduction port of the condensing section via a steam balance pipe, and condensed water discharged from the drain port in the condensing section flows into the liquid level tank by its own gravity; the subcooling section is connected to a drain pipe for outputting condensed water, and a drain regulating valve is provided on the drain pipe; the opening of the drain regulating valve is controlled according to a liquid level signal from the liquid level tank.

[0019] During application, high-pressure steam can be introduced into the steam heating unit, which includes not only a condensing section but also a subcooling section. The saturated water condensed after the high-pressure steam enters the condensing section for heat exchange is not discharged directly, but enters the liquid level tank and then the subcooling section. The top of the liquid level tank is connected to the high-pressure steam inlet in the condensing section through a steam balance pipe, so that the high-pressure steam inlet and the liquid level tank maintain the same pressure. The hydrophobicity in the condensing section can flow smoothly into the liquid level tank by its own gravity. A hydrophobicity regulating valve is installed on the hydrophobicity pipe after the subcooling section. The opening of the hydrophobicity regulating valve is controlled by the liquid level signal in the liquid level tank. The pressure on the steam-water side of the entire unit before the hydrophobicity regulating valve can be maintained at a high pressure, avoiding the generation of low pressure in the entire unit, which may cause the hydrophobicity to flash in the subcooling section.

[0020] It can be seen that the steam heating unit provided by the present invention is not only provided with a condensation section, but also with a supercooling section. After the high-pressure steam is introduced, the drain in the condensation section is not discharged directly, but first passes into the liquid level tank and then into the supercooling section, and exchanges heat with the medium to be heated in the supercooling section, so that the drain temperature reaches a certain supercooling, reducing the intensity of the flash evaporation of the drain after the drain regulating valve, reducing the degree of damage to the drain pipe, and helping to increase the service life of the drain pipe.

[0021] The present invention also provides a steam preheater and a garbage incinerator respectively applying the steam heating unit, which is beneficial to protecting the drain pipeline of the steam preheater and prolonging the service life of the drain pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] FIG1 is a schematic structural diagram of a steam heating unit provided in an embodiment of the present invention;

[0024] FIG2 is a schematic structural diagram of a steam preheating system provided in an embodiment of the present invention;

[0025] Among them, in Figures 1 and 2: steam heating unit 100; steam balancing pipe 101; liquid level tank 102; liquid level gauge 103; condensing section 104; subcooling section 105; drain pipe 106; drain regulating valve 107; high-pressure condensing section 1; high-pressure subcooling section 2; medium-pressure condensing section 3; medium-pressure subcooling section 4; low-pressure condensing section 5; low-pressure subcooling section 6; high-pressure liquid level tank 7; medium-pressure liquid level tank 8; low-pressure liquid level tank 9; high-pressure drain regulating valve 10; medium-pressure drain regulating valve 11; low-pressure drain regulating valve 12; high-pressure liquid level tank level gauge 13; medium-pressure liquid level tank level gauge 14; low-pressure liquid level tank level gauge 15; steam balancing pipe 16; high-pressure steam inlet regulating valve 17. DETAILED DESCRIPTION

[0026] Embodiments of the present invention disclose a steam preheating system that utilizes a steam heating unit with a condensing section and a subcooling section to heat a medium to be heated. After the introduction of high-pressure steam, drain water from the condensing section is fed through a liquid level tank into the subcooling section for further heat exchange with the medium to be heated. This subcools the drain water to a certain temperature, reduces the severity of flash evaporation of the drain water after the drain regulating valve in the drain pipe connected to the subcooling section, reduces damage to the drain pipe, and improves the service life of the drain pipe. Embodiments of the present invention also disclose a steam preheater and a waste incinerator utilizing the above-described steam preheating system, which helps protect the drain pipe of the steam preheater and improves its service life.

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Please refer to Figures 1-2. An embodiment of the present invention provides a steam preheating system, including at least one steam heating unit 100 that uses steam to heat a medium to be heated; the steam heating unit 100 includes a condensing section 104, a subcooling section 105 and a liquid level tank 102; the condensing section 104 is used to introduce steam, and the discharge port of the condensing section 104 is connected to the subcooling section 105 through the liquid level tank 102; the liquid level tank 102 is connected to the steam inlet of the condensing section 104 through a steam balance pipe 101, and the condensed water discharged from the discharge port in the condensing section 104 flows into the liquid level tank 102 by its own gravity; the subcooling section 105 is connected to a drain pipe 106 for outputting condensed water, and a drain regulating valve 107 is provided on the drain pipe 106; the opening of the drain regulating valve 107 is controlled according to the liquid level signal of the liquid level tank 102.

[0029] During application, high-pressure steam can be introduced into the steam heating unit 100, which includes not only a condensing section 104 but also a subcooling section 105. The saturated water condensed after the high-pressure steam enters the condensing section 104 for heat exchange is not discharged directly, but enters the liquid level tank 102 and then enters the subcooling section 105. The top of the liquid level tank 102 is connected to the high-pressure steam inlet of the condensing section 104 through a steam balance pipe 101, so that the high-pressure steam inlet and the liquid level tank 102 maintain the same pressure. The hydrophobicity in the condensing section 104 can flow smoothly into the liquid level tank 102 by its own gravity, and the high pressure in the liquid level tank 102 will not cause the hydrophobicity to flow smoothly. A drain regulating valve 107 is provided on the drain pipe 106 after the subcooling section 105. The opening of the drain regulating valve 107 is controlled by the liquid level signal in the liquid level tank 102, so that the pressure on the steam-water side of the entire unit before the drain regulating valve 107 can be maintained at a high pressure, thereby avoiding the flash evaporation of drain water in the subcooling section 105 caused by low pressure in the entire unit.

[0030] It can be seen that the steam heating unit 100 provided in this embodiment is not only provided with a condensation section 104, but also provided with a supercooling section 105. After the high-pressure steam is introduced, the drain of the condensation section 104 is not discharged directly, but first passes into the liquid level tank 102, and then passes into the supercooling section 105, and exchanges heat with the medium to be heated in the supercooling section 105, so that the drain temperature reaches a certain level of supercooling, thereby reducing the intensity of flash evaporation of the drain after the drain regulating valve 107, reducing the degree of damage to the drain pipe 106, and helping to improve the service life of the drain pipe 106.

[0031] In some embodiments, the opening of the hydrophobic regulating valve 107 is controlled by a controller; a liquid level gauge 103 for detecting the liquid level information in the liquid level tank 102 is provided in the liquid level tank 102, and the liquid level gauge 103 is connected to the controller signal and can send a signal containing the liquid level information of the liquid level tank 102 to the controller.

[0032] In the above-mentioned steam preheating system, the number of the steam heating unit 100 can be one, preferably multiple, and the steam pressure levels used by the steam heating units 100 are different.

[0033] The steam heating units 100 are arranged one by one, and along the arrangement direction, the pressure level of the steam used by each steam heating unit 100 gradually decreases or gradually increases.

[0034] In order to completely avoid flashing in the drain pipe of the steam preheating system, protect the drain pipe from damage by flash steam to the greatest extent, and increase the service life of the drain pipe, in the above-mentioned steam preheating system, among any two adjacent steam heating units 100, the condensate discharged from the subcooling section 105 of the steam heating unit 100 with a higher steam pressure level is transported to the liquid level tank 102 of the steam heating unit 100 with a lower steam pressure level through the drain pipe 106 connected to the subcooling section 105.

[0035] When in use, the drain from the drain pipe 106 of the steam heating unit 100 enters the liquid level tank 102 of an adjacent steam heating unit 100 with a lower steam pressure level. Due to the pressure reduction, the drain flashes in the liquid level tank, and the generated flash steam enters the condensing section 104 of the steam heating unit 100 with a lower steam pressure level through the steam balance pipe, thereby recycling the flash steam and improving the heat exchange efficiency.

[0036] Obviously, the drain of the steam heating unit 100 using high-pressure steam is sequentially introduced into the liquid level tank 102 of the steam heating unit 100 with gradually decreasing pressure levels, thereby realizing step-by-step pressure reduction. Moreover, each time the drain is depressurized, flash evaporation occurs in the liquid level tank 102, thereby avoiding flash evaporation in the drain pipe 106, which is beneficial to protecting the drain pipe 106 from damage and improving the service life of the drain pipe 106.

[0037] In addition, in the steam preheating system provided in this embodiment, the drain is gradually depressurized and finally converges to achieve low-pressure drain. Only one drain pipeline needs to be set up to complete the drain, which can reduce the cost of the entire drain pipeline system. There is no need to set up a separate high-pressure drain pipeline to transport the high-pressure drain formed after the high-pressure steam is condensed, thereby improving the safety of the operation of the entire drain pipeline system.

[0038] Among all the steam heating units 100 , the subcooling section 105 of the steam heating unit 100 with the lowest applied steam pressure level is connected to the drain tank or deaerator through the drain pipe 106 connected to the subcooling section 105 .

[0039] In some embodiments, the steam preheating system comprises three steam heating units 100, each of which has a condensing section 104 for introducing high-pressure steam, medium-pressure steam, and low-pressure steam, respectively. In this embodiment, after condensation in the condensing section 104, each steam level is drained and first passes through the subcooling section 105 before entering the liquid level tank 102 at a lower pressure for flash evaporation.

[0040] In the above-mentioned steam preheating system, the heated medium heated by the steam heating unit 100 is the air for inputting into the boiler. Of course, the heated medium can also be set to water, etc., which is not specifically limited in this embodiment.

[0041] The following describes in detail the principle of the steam preheating system with three steam heating units 100, which respectively introduce high-pressure steam, medium-pressure steam and low-pressure steam, with reference to FIG2 :

[0042] In Figure 2, 1 is the high-pressure condensing section, 2 is the high-pressure subcooling section, 3 is the medium-pressure condensing section, 4 is the medium-pressure subcooling section, 5 is the low-pressure condensing section, 6 is the low-pressure subcooling section, 7 is the high-pressure liquid level tank, 8 is the medium-pressure liquid level tank, 9 is the low-pressure liquid level tank, 10 is the high-pressure steam drain regulating valve, 11 is the medium-pressure steam drain regulating valve, 12 is the low-pressure steam drain regulating valve, 13 is the high-pressure liquid level tank level gauge, 14 is the medium-pressure liquid level tank level gauge, 15 is the low-pressure liquid level tank level gauge, 16 is the steam balance pipe, and 17 is the high-pressure steam inlet regulating valve.

[0043] The primary air for entering the boiler enters the air preheater and passes through the low-pressure subcooling section 6, the low-pressure condensing section 5, the medium-pressure subcooling section 4, the medium-pressure condensing section 3, the high-pressure subcooling section 2 and the high-pressure condensing section 1 in sequence.

[0044] High-pressure steam enters the high-pressure condensation section 1 through the high-pressure steam inlet regulating valve 17, and the condensed saturated water enters the high-pressure liquid level tank 7, and then enters the high-pressure subcooling section 2. The top of the high-pressure liquid level tank 7 is connected to the high-pressure steam inlet of the high-pressure condensation section 1 through the steam balance pipe 11, so that the high-pressure steam inlet and the high-pressure liquid level tank 7 maintain the same pressure. The hydrophobicity in the high-pressure condensation section 1 can flow smoothly into the high-pressure liquid level tank 7 by its own gravity. In order to control the system pressure on the high-pressure hydrophobicity side, a high-pressure hydrophobicity regulating valve 10 is set on the hydrophobicity pipe after the high-pressure subcooling section 2. The opening of the high-pressure hydrophobicity regulating valve 10 is controlled by the liquid level signal in the high-pressure liquid level tank 7. The pressure on the steam-water side of the system before the high-pressure hydrophobicity regulating valve 10 can be maintained at a high pressure to avoid the generation of low pressure and the flash evaporation of hydrophobicity in the high-pressure subcooling section 2. The high-pressure drain enters the medium-pressure liquid level tank 8 after passing through the high-pressure drain regulating valve 10. Due to the pressure reduction, the high-pressure drain flashes in the medium-pressure hydraulic tank 8. The generated flash steam passes through the steam balance pipe 16 and the medium-pressure steam inlet of the medium-pressure condensing section 3 and merges with the medium-pressure steam before entering the medium-pressure condensing section 3.

[0045] Similarly, the medium-pressure steam enters the medium-pressure condensation section 3, and the saturated water after condensation enters the medium-pressure liquid level tank 8, and then enters the medium-pressure subcooling section 4. The top of the medium-pressure liquid level tank 8 is connected to the medium-pressure steam inlet through a steam balance pipe 16, so that the medium-pressure steam inlet and the medium-pressure liquid level tank 8 maintain the same pressure, and the hydrophobicity in the medium-pressure condensation section 4 can smoothly flow into the medium-pressure liquid level tank 8 by its own gravity. In order to control the system pressure on the medium-pressure hydrophobicity side, a medium-pressure hydrophobicity regulating valve 11 is set on the hydrophobicity pipe after the medium-pressure subcooling section 4. The opening of the medium-pressure hydrophobicity regulating valve 11 is controlled by the liquid level signal of the medium-pressure liquid level tank 8. The pressure on the steam-water side of the system before the medium-pressure hydrophobicity regulating valve 11 can be maintained at a pressure close to that of the medium-pressure steam, avoiding the generation of low pressure in the system and causing the hydrophobicity to flash in the medium-pressure subcooling section 4. The medium-pressure drain enters the low-pressure liquid level tank 9 after passing through the medium-pressure drain regulating valve 11. Due to the pressure reduction, the medium-pressure drain flashes in the low-pressure hydraulic tank 9. The generated flash steam passes through the steam balance pipe 16 and merges with the low-pressure steam at the low-pressure steam inlet of the low-pressure condensing section 5 and then enters the low-pressure condensing section 5.

[0046] Similarly, low-pressure steam enters the low-pressure condensation section 5, and the condensed saturated water enters the low-pressure liquid level tank 9, and then enters the low-pressure subcooling section 6. The top of the low-pressure liquid level tank 9 is connected to the low-pressure steam inlet through a steam balance pipe 16, so that the low-pressure steam inlet and the low-pressure liquid level tank 9 maintain the same pressure. The drain in the low-pressure condensation section 5 can smoothly flow into the low-pressure liquid level tank 9 by its own gravity. In order to control the system pressure on the low-pressure drain side, a low-pressure drain regulating valve 12 is installed on the drain pipe after the low-pressure subcooling section. The opening of the low-pressure drain regulating valve 12 is controlled by the liquid level signal in the low-pressure liquid level tank 9. The pressure on the steam-water side of the system before the low-pressure drain regulating valve 12 can be maintained at a pressure close to that of the low-pressure steam, avoiding the generation of low pressure in the system and the flash evaporation of drain in the low-pressure subcooling section 6. After passing through the low-pressure drain regulating valve 12, the low-pressure drain enters the drain tank or deaerator through the drain pipe. The low-pressure drain temperature is controlled at the saturation temperature under the corresponding pressure of the rear-end receiving body (i.e. drain tank or deaerator) to ensure that the low-pressure drain does not flash in the drain pipe.

[0047] The present invention further provides a steam preheater, including a steam preheating system, which is the steam preheating system provided in the above embodiment.

[0048] An embodiment of the present invention further provides a waste incinerator, comprising a steam preheater, which is the above-mentioned steam preheater.

[0049] The steam preheater and waste incinerator provided in the embodiments of the present invention each utilize the steam preheating system provided in the aforementioned embodiments, thereby protecting the steam preheater's drain pipe and extending its lifespan. Of course, the steam preheater and waste incinerator provided in this embodiment also provide other benefits related to the steam preheating system provided in the aforementioned embodiments, which will not be further elaborated here.

[0050] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0051] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A steam preheating system, characterized in that: It comprises at least one steam heating unit which utilizes steam to heat the medium to be heated; the steam heating unit comprises a condensation section, a subcooling section and a liquid level tank; the condensation section is used to introduce steam, and the drain port of the condensation section is connected with the subcooling section through the liquid level tank; the liquid level tank is connected with the steam introduction port of the condensation section through a steam balance pipe, and the condensed water discharged from the drain port in the condensation section flows into the liquid level tank by its own gravity; the subcooling section is connected with a drain pipe for outputting condensed water, and a drain regulating valve is provided on the drain pipe; the opening of the drain regulating valve is controlled according to the liquid level signal of the liquid level tank.

2. The steam preheating system according to claim 1, characterized in that: The opening of the drain regulating valve is controlled by a controller; a liquid level gauge is arranged in the liquid level tank, and the liquid level gauge is connected to the controller signal.

3. The steam preheating system according to claim 1 or 2, characterized in that: There are multiple steam heating units, and each of the steam heating units uses a different steam pressure level.

4. The steam preheating system according to claim 3, characterized in that: The steam heating units are arranged one by one, and along the arrangement direction, the pressure level of the steam used by each steam heating unit gradually decreases or increases.

5. The steam preheating system according to claim 4, characterized in that: In any two adjacent steam heating units, the condensate discharged from the supercooling section of the steam heating unit with a higher steam pressure level is transported to the liquid level tank of the steam heating unit with a lower steam pressure level through the drain pipe connected to the supercooling section.

6. The steam preheating system according to claim 5, characterized in that: Among all the steam heating units, the subcooling section of the steam heating unit with the lowest applied steam pressure level is connected to the drain tank or the deaerator through the drain pipe connected to the subcooling section.

7. The steam preheating system according to claim 4, characterized in that: There are three steam heating units, and the condensation sections of the three units are used to introduce high-pressure steam, medium-pressure steam and low-pressure steam respectively.

8. The steam preheating system according to claim 1, characterized in that: The medium to be heated is wind for inputting into the boiler.

9. A steam preheater, characterized in that: It comprises a steam preheating system, and the steam preheating system is the steam preheating system according to any one of claims 1-8.

10. A garbage incinerator, characterized in that: It comprises a steam preheater, and the steam preheater is the steam preheater according to claim 9.

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