Steam turbine system

Abstract

The steam turbine system according to at least one embodiment of this disclosure comprises: a steam turbine; a main steam supply line which supplies steam to an upstream stage of the steam turbine; an intermediate-stage steam supply line which supplies the steam to an intermediate stage downstream of the upstream stage of the steam turbine; and an agent injection device which injects, into the intermediate-stage steam supply line, an agent for modifying the steam.

Description

Technical Field

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[0001] The present disclosure relates to a steam turbine system. This application claims priority based on Japanese Patent Application No. 2022-023361 filed with the Japan Patent Office on February 18, 2022, the content of which is incorporated herein by reference.

Background Art

[0002] For example, in a combined cycle power plant equipped with a gas turbine and a steam turbine, an exhaust heat recovery boiler may be connected to effectively utilize the heat of the exhaust gas exhausted from the gas turbine (see, for example, Patent Document 1). In the power plant described in Patent Document 1, an exhaust heat recovery device is provided as an exhaust heat recovery boiler for effectively utilizing the heat of the exhaust gas. This exhaust heat recovery device has a superheater, an evaporator, and a carbon economizer. In this exhaust heat recovery device, high-temperature exhaust gas is supplied in the order of the superheater, the evaporator, and the carbon economizer, so that heat of the exhaust gas is used to generate high-temperature and high-pressure steam and supply it to a steam turbine.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to more effectively utilize the heat of the exhaust gas, further improvement in the efficiency of the steam turbine system is required.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to further improve the efficiency of the steam turbine system.

Means for Solving the Problems

[0006] A steam turbine system according to at least one embodiment of this disclosure is Steam turbine and A main steam supply line for supplying steam to the uppermost stage of the steam turbine, An intermediate stage steam supply line for supplying steam to an intermediate stage downstream of the uppermost stage of the steam turbine, A chemical injection device for injecting a chemical agent for reforming steam into the aforementioned intermediate steam supply line, It is equipped with. [Effects of the Invention]

[0007] According to at least one embodiment of this disclosure, it is possible to further improve the efficiency of the steam turbine system. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows a schematic overall configuration of a combined plant according to one embodiment. [Figure 2] This figure shows a schematic configuration of a part of a combined plant according to another embodiment. [Figure 3A] This is a schematic side view of a steam turbine stator blade. [Figure 3B] This is a schematic diagram showing the cross-section taken along the line III-III in Figure 3A. [Figure 4A] This is a schematic side view of a steam turbine stator blade. [Figure 4B] This is a schematic diagram showing the cross-section along the line IV-IV in Figure 4A. [Figure 5] This is a schematic side view of a steam turbine stator blade. [Figure 6A] This is a schematic side view of a steam turbine stator blade. [Figure 6B] This is a schematic diagram showing the cross-section along the line VI-VI in Figure 6A. [Modes for carrying out the invention]

[0009] Hereinafter, several embodiments of this disclosure will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described or shown in the drawings as embodiments are not intended to limit the scope of this disclosure, but are merely illustrative examples. For example, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" should not only strictly describe such arrangements, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. For example, expressions such as "identical," "equal," and "homogeneous" that describe things being in an equal state not only describe a state of being strictly equal, but also describe a state in which there is a tolerance or a difference that is sufficient to achieve the same function. For example, expressions describing shapes such as squares or cylinders shall not only represent geometrically precise shapes such as squares or cylinders, but also shapes that include protrusions, chamfers, etc., to the extent that the same effect can be achieved. On the other hand, expressions such as "to possess," "to be equipped with," "to have," "to include," or "to have" a single component are not exclusive expressions that exclude the existence of other components.

[0010] <Combined Plant Configuration> Figure 1 shows a schematic overall configuration of a combined plant 2 (2A) according to one embodiment. The combined plant 2 consists of a gas turbine 4 as the prime mover, a steam turbine system 100, and a steam generator for generating steam. vessel The system includes a heat recovery boiler 5 and a chimney 9 that releases exhaust gas discharged from the heat recovery boiler 5 into the atmosphere. The steam turbine system 100 functions as a steam utilization facility that uses the steam generated by the heat recovery boiler 5. The heat recovery boiler 5 and the steam turbine system 100 also constitute a heat recovery plant 200 for recovering waste heat from the gas turbine 4.

[0011] <Gas turbine configuration> The gas turbine 4 includes a compressor 12 that compresses air, a combustor 14 that burns fuel using the compressed air generated by the compressor 12, and a turbine 16 that is driven by the combustion gas generated by the combustor 14. In the illustrated form, a generator 19 is disposed on the same axis as the compressor 12 and the turbine 16, and the rotors of the compressor 12, the turbine 16, and the generator 19 are configured to rotate integrally.

[0012] <Configuration of Steam Turbine System> A steam turbine system 100(100A) according to an embodiment includes a plurality of steam turbines 101, a condenser 108 that cools the steam discharged from the most downstream steam turbine 101 and returns it to water, and a chemical injection device 150. The steam turbine system 100 includes, as the plurality of steam turbines 101, a high-pressure steam turbine 102, an intermediate-pressure steam turbine 104, and a low-pressure steam turbine 106. The steam outlet of the intermediate-pressure steam turbine 104 and the steam inlet of the low-pressure steam turbine 106 are connected via an intermediate-pressure exhaust line 110, and the steam outlet of the low-pressure steam turbine 106 and the condenser 108 are connected via a low-pressure exhaust line 112. In the illustrated form, the compressor 12, the turbine 16, the generator 19, the high-pressure steam turbine 102, the intermediate-pressure steam turbine 104, and the low-pressure steam turbine 106 are disposed on the same axis, and the respective rotors are configured to rotate integrally.

[0013] <Configuration of Heat Recovery Boiler> The exhaust heat recovery boiler 5 includes an exhaust gas flow path 18 (heat medium flow path) through which the exhaust gas of the gas turbine 4 flows, and a plurality of heat exchangers 20 provided in the exhaust gas flow path 18. The plurality of heat exchangers 20 are, in order from the downstream side in the flow direction of the exhaust gas in the exhaust gas flow path 18, a first low-pressure carbonizer 22 (first carbonizer), an ultra-low-pressure evaporator 121 (second evaporator), an ultra-low-pressure superheater 123 (second superheater), a second low-pressure carbonizer 24 (second carbonizer), a low-pressure evaporator 26 (first evaporator), a low-pressure superheater 28 (first superheater), a first high-pressure carbonizer 30, a medium-pressure evaporator 32, a medium-pressure superheater 34, a second high-pressure carbonizer 36, a high-pressure evaporator 38, a first high-pressure superheater 40, a first reheater 42, a second high-pressure superheater 44, and a second reheater 46. A medium-pressure carbonizer 31 is provided in parallel with the first high-pressure carbonizer 30 between the low-pressure superheater 28 and the medium-pressure evaporator 32 in the exhaust gas flow path 18.

[0014] The condenser 108 and the first low-pressure carbonizer 22 are connected by a feed water line 48, and a feed water pump 50 for supplying the condensed water discharged from the condenser 108 to the first low-pressure carbonizer 22 is provided in the feed water line 48.

[0015] The first low-pressure carbonizer 22 heats the water supplied from the feed water line 48 by heat exchange with the exhaust gas. A part of the water heated by the first low-pressure carbonizer 22 is supplied to the second low-pressure carbonizer 24 via a feed water line 52 connecting the first low-pressure carbonizer 22 and the second low-pressure carbonizer 24.

[0016] A feed water line 53 branched from the feed water line 52 is connected to the ultra-low-pressure evaporator 121, and a part of the water heated by the first low-pressure carbonizer 22 is supplied to the ultra-low-pressure evaporator 121 via the feed water line 53. The ultra-low-pressure evaporator 121 heats and evaporates the water supplied from the first low-pressure carbonizer 22 via the feed water line 53 by heat exchange with the exhaust gas to generate ultra-low-pressure steam. The ultra-low-pressure steam generated by the ultra-low-pressure evaporator 121 is supplied to the ultra-low-pressure superheater 123 via a steam line 55 connecting the ultra-low-pressure evaporator 121 and the ultra-low-pressure superheater 123.

[0017] The ultra-low pressure superheater 123 superheats the ultra-low pressure steam supplied from the ultra-low pressure evaporator 121 via the steam line 55 by heat exchange with the exhaust gas to produce ultra-low pressure superheated steam. The ultra-low pressure superheated steam produced in the ultra-low pressure superheater 123 is supplied to the intermediate stages of the low-pressure steam turbine 106 via the low-pressure intermediate stage steam supply line 57 (intermediate stage steam supply line), which connects the ultra-low pressure superheater 123 to the intermediate stages of the low-pressure steam turbine 106.

[0018] The second low-pressure economizer 24 heats the water supplied from the first low-pressure economizer 22 via the water supply line 52 by heat exchange with the exhaust gas. A portion of the water heated in the second low-pressure economizer 24 is supplied to the low-pressure evaporator 26 via the water supply line 54 connecting the second low-pressure economizer 24 and the low-pressure evaporator 26.

[0019] The low-pressure evaporator 26 heats and evaporates water supplied from the second low-pressure economizer 24 via the feedwater line 54 through heat exchange with the exhaust gas, thereby generating low-pressure steam. A portion of the low-pressure steam generated in the low-pressure evaporator 26 is supplied to the low-pressure superheater 28 via a steam line 56 connecting the low-pressure evaporator 26 and the low-pressure superheater 28.

[0020] The low-pressure superheater 28 superheats the low-pressure steam supplied from the low-pressure evaporator 26 via the steam line 56 by heat exchange with the exhaust gas to generate low-pressure superheated steam. The low-pressure superheated steam generated in the low-pressure superheater 28 flows into the intermediate-pressure exhaust line 110 via the steam line 58 connecting the low-pressure superheater 28 and the intermediate-pressure exhaust line 110, and from the intermediate-pressure exhaust line 110 flows into the steam inlet of the low-pressure steam turbine 106.

[0021] A portion of the water heated in the second low-pressure economizer 24 is supplied to the medium-pressure economizer 31 via the water supply line 60. The water supply line 60 is branched off from the water supply line 54 and connected to the medium-pressure economizer 31.

[0022] The intermediate-pressure economizer 31 heats the water supplied from the second low-pressure economizer 24 via the water supply line 60 through heat exchange with the exhaust gas. The water heated in the intermediate-pressure economizer 31 is supplied to the intermediate-pressure evaporator 32 via the water supply line 64 that connects the intermediate-pressure economizer 31 and the intermediate-pressure evaporator 32.

[0023] The intermediate-pressure evaporator 32 heats and evaporates water supplied from the intermediate-pressure economizer 31 via the feedwater line 64 through heat exchange with the exhaust gas, thereby generating intermediate-pressure steam. A portion of the intermediate-pressure steam generated in the intermediate-pressure evaporator 32 is supplied to the intermediate-pressure superheater 34 via a steam line 66 connecting the intermediate-pressure evaporator 32 and the intermediate-pressure superheater 34.

[0024] The intermediate-pressure superheater 34 superheats the intermediate-pressure steam supplied from the intermediate-pressure evaporator 32 via the steam line 66 by heat exchange with the exhaust gas to generate intermediate-pressure superheated steam. The intermediate-pressure superheated steam generated in the intermediate-pressure superheater 34 is supplied via the steam line 68 to the high-pressure exhaust line 114, which connects the steam outlet of the high-pressure steam turbine 102 to the steam inlet of the first reheater 42. The intermediate-pressure superheated steam generated in the intermediate-pressure superheater 34 flows into the first reheater 42 via the steam line 68 and the high-pressure exhaust line 114.

[0025] A portion of the water heated in the second low-pressure economizer 24 is supplied to the first high-pressure economizer 30 via a water supply line 70 that connects the second low-pressure economizer 24 and the first high-pressure economizer 30.

[0026] The first high-pressure economizer 30 heats the heated water supplied from the second low-pressure economizer 24 via the water supply line 70 through heat exchange with the exhaust gas. The heated water heated in the first high-pressure economizer 30 is supplied to the second high-pressure economizer 36 via the water supply line 74 that connects the first high-pressure economizer 30 and the second high-pressure economizer 36.

[0027] The second high-pressure economizer 36 heats the high-pressure heated water supplied from the first high-pressure economizer 30 via the water supply line 74 by heat exchange with the exhaust gas. The high-pressure heated water heated in the second high-pressure economizer 36 is supplied to the high-pressure evaporator 38 via the water supply line 76 that connects the second high-pressure economizer 36 to the high-pressure evaporator 38.

[0028] The high-pressure evaporator 38 heats and evaporates water supplied from the second high-pressure economizer 36 via the feedwater line 76 through heat exchange with exhaust gas, thereby generating high-pressure steam. The high-pressure steam generated in the high-pressure evaporator 38 is supplied to the first high-pressure superheater 40 via the steam line 78 connecting the high-pressure evaporator 38 and the first high-pressure superheater 40.

[0029] The first high-pressure superheater 40 generates high-pressure superheated steam by superheating high-pressure steam supplied from the high-pressure evaporator 38 via the steam line 78 through heat exchange with exhaust gas. The high-pressure superheated steam generated in the first high-pressure superheater 40 is supplied to the second high-pressure superheater 44 via the steam line 80 connecting the first high-pressure superheater 40 and the second high-pressure superheater 44.

[0030] The second high-pressure superheater 44 further superheats the high-pressure superheated steam supplied from the first high-pressure superheater 40 via the steam line 80 through heat exchange with the exhaust gas. The high-pressure superheated steam superheated in the second high-pressure superheater 44 is supplied to the high-pressure steam turbine 102 via the steam line 97 connecting the second high-pressure superheater 44 to the steam inlet of the high-pressure steam turbine 102.

[0031] The first reheater 42 heats the steam supplied to the first reheater 42 from the steam outlet of the high-pressure steam turbine 102 via the high-pressure exhaust line 114, and the steam supplied to the first reheater 42 from the medium-pressure superheater 34 via the steam line 68 and the high-pressure exhaust line 114, through heat exchange with the exhaust gas. The steam heated in the first reheater 42 is supplied to the second reheater 46 via the steam line 82 that connects the first reheater 42 and the second reheater 46.

[0032] The second reheater 46 heats the steam supplied via the steam line 82 through heat exchange with the exhaust gas. The steam heated in the second reheater 46 is supplied to the intermediate-pressure steam turbine 104 via a steam line 98 that connects the second reheater 46 to the steam inlet of the intermediate-pressure steam turbine 104.

[0033] Thus, the waste heat recovery boiler 5 according to one embodiment is a quadruple-pressure system having a high-pressure system, an intermediate-pressure system, a low-pressure system, and an ultra-low-pressure system.

[0034] <Drug infusion device> One embodiment of the chemical injection device 150 is for injecting a chemical that reforms steam into a low-pressure intermediate steam supply line 57, and includes a chemical tank 151 and a chemical injection pump 153. The chemical tank 151 is a tank for storing chemicals used to reform steam. The chemical injection pump 153 is a pump for injecting the chemical from the chemical tank 151 into the low-pressure intermediate steam supply line 57 via the chemical injection line 155. The drug injection line 155 is connected to the low-pressure intermediate steam supply line 57. In one embodiment of the steam turbine system 100A, the chemicals pumped by the chemical injection pump 153 are supplied together with the steam flowing through the low-pressure intermediate steam supply line 57 to the main flow path through which the main steam flows inside the low-pressure steam turbine 106. Furthermore, a mixing section 157 may be provided at the connection point between the chemical injection line 155 and the low-pressure intermediate steam supply line 57 for mixing the chemical from the chemical injection line 155 with the steam flowing through the low-pressure intermediate steam supply line 57.

[0035] (A chemical agent that modifies steam) Specifically, as a vapor reforming agent, volatile amine compounds having volatility, surfactant properties, and corrosion-preventive properties ( leather Membrane-forming amines and volatile nonamine compounds are preferably used.

[0036] Specific examples of volatile amines include long-chain saturated aliphatic amines such as monoamines dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, octadecylamine, nonadecylamine, eicosylamine, and docosylamine; long-chain unsaturated aliphatic amines such as oleylamine, ricinoleylamine, linoleylamine, and linolenylamine; mixed amines such as coconut oil amine and hardened beef tallow amine; and mixtures thereof.

[0037] Furthermore, polyamines represented by the following general formula are also preferably used. R1-[NH-(CH2)m]n-NH2 In the above formula, R1 represents a saturated or unsaturated hydrocarbon having 10 to 22 carbon atoms, m is an integer from 1 to 8, and n is an integer from 1 to 7. When n is 2 or greater, multiple [NH-(CH2)m]n can be the same or different.

[0038] The hydrocarbon group R1 may be linear, branched, or cyclic. Specifically, examples include alkyl groups, alkenyl groups, alkadienyl groups, and alkynyl groups. More preferably, linear alkyl groups and linear alkenyl groups are used, in which case the number of carbon atoms is 15 to 22. From the viewpoint of corrosion suppression, m is preferably an integer from 2 to 6. Examples of the (CH2)m group include a methylene group, an ethylene group (dimethylene group), a propylene group (trimethylene group), or a butylene group (tetramethylene group), but a propylene group is more preferred. Furthermore, from the viewpoint of corrosion suppression, n is preferably an integer from 1 to 3.

[0039] Specific examples of such polyamines include dodecylaminomethyleneamine, dodecylaminodimethyleneamine, dodecylaminotrimethyleneamine (N-stearyl-1,3-propanediamine), and tetradecyl, hexadecyl, and octadecyl compounds corresponding to these polyamines, octadecenylaminotrimethyleneamine, octadecenylaminodi-(trimethylamino)-trimethyleneamine, palmitylaminotrimethyleneamine, and tallow alkyldiamine ethoxylate. It is more preferable to use N-oleyl-1,3-propanediamine (i.e., N-octadecenylpropane-3-diamine), which is readily available in sufficient purity. Akzo's trade name "Ethiduomine" can also be suitably used.

[0040] Examples of volatile nonamine compounds include polyethylene(20) sorbitan monostearate, sorbitan monostearate, and sorbitan monolaurate.

[0041] Furthermore, it is possible to use only one of these substances as a vapor reforming agent, or to use a mixture of two or more substances as a vapor reforming agent.

[0042] As steam passes through the steam turbine 101, it loses energy and its temperature and pressure decrease as it moves from upstream to downstream. Therefore, near the turbine stator blade stage closest to the downstream stage of the steam turbine 101 (low-pressure steam turbine 106), some of the steam condenses and exists in the airflow as fine water droplets, some of which adhere to the surface of the turbine stator blades. These water droplets quickly grow on the blade surface to form a liquid film. The liquid film is constantly exposed to the high-speed steam flow, and as this film grows and increases in thickness, some of it breaks off due to the steam flow and scatters as coarser liquid droplets. The scattered droplets are gradually accelerated by the steam flow and flow downstream. Larger droplets have greater mass and are therefore less likely to be accelerated to steam velocity by the steam flow, and instead of being able to pass between the turbine blades on the main steam, they collide with the turbine blades. The collision of droplets can hinder the rotation of the turbine blades, sometimes resulting in braking losses. Furthermore, since the peripheral speed of turbine blades can exceed the speed of sound, if scattered liquid droplets collide with the turbine blades, they can erode the surface and cause erosion.

[0043] Therefore, in the steam turbine system 100 according to one embodiment, the steam turbine system 100 is configured as follows. That is, the steam turbine system 100 according to one embodiment includes a steam turbine 101 (low-pressure steam turbine 106), a main steam supply line (intermediate-pressure exhaust line 110) for supplying steam to the uppermost stage of the steam turbine 101 (low-pressure steam turbine 106), an intermediate stage steam supply line (low-pressure intermediate stage steam supply line 57) for supplying steam to the intermediate stage downstream of the uppermost stage of the steam turbine 101 (low-pressure steam turbine 106), and a chemical injection device 150 for injecting chemicals to reform the steam into the intermediate stage steam supply line (low-pressure intermediate stage steam supply line 57).

[0044] According to one embodiment of the steam turbine system 100, by supplying steam to which a steam reforming agent has been added to the intermediate stage of the steam turbine 101 (low-pressure steam turbine 106), the efficiency of the steam turbine system 100 is improved by supplying steam to the intermediate stage, and the aforementioned braking losses can be suppressed by making the droplets generated in the steam turbine 101 (low-pressure steam turbine 106) finer. This improves the efficiency of the steam turbine system 100.

[0045] In a steam turbine system 100 according to one embodiment, the steam turbine 101 may include a high-pressure steam turbine 102, an intermediate-pressure steam turbine 104, and a low-pressure steam turbine 106. The intermediate stage steam supply line may include a low-pressure intermediate stage steam supply line 57 for supplying steam to the intermediate stage of the low-pressure steam turbine 106. The chemical injection device 150 may be capable of injecting chemicals into the low-pressure intermediate stage steam supply line 57.

[0046] As a result, steam with a steam reforming agent added is supplied to the intermediate stage and beyond of the low-pressure steam turbine 106, where there is a high probability that some of the steam will condense and exist in the airflow as fine water droplets. This makes it possible to efficiently refine the droplets generated in the steam turbine 101.

[0047] In one embodiment of the steam turbine system 100, the intermediate stage may be the downstream stage of the steam turbine 101 (low-pressure steam turbine 106), or the stage one stage upstream of the downstream stage. As a result, steam with a steam reforming agent added is supplied to the downstream stage, or to the stage one stage upstream of the downstream stage, where there is a high possibility that some of the steam will condense and exist in the airflow as fine water droplets. This makes it possible to efficiently refine the droplets generated in the steam turbine 101 (low-pressure steam turbine 106).

[0048] In one embodiment of the steam turbine system 100, the intermediate stage steam supply line (low-pressure intermediate stage steam supply line 57) may be a steam line branched from the main steam supply line through which steam or water circulates to the steam turbine 101 (low-pressure steam turbine 106), condenser 108, and heat exchanger 20, for supplying steam to the upstream stage of the steam turbine 101 (low-pressure steam turbine 106). This allows steam to be supplied to the intermediate stage of the steam turbine 101 (low-pressure steam turbine 106), condenser 108, and heat exchanger 20 from a steam line branched from the main steam supply line through which steam or water circulates, in order to supply steam to the upstream stage of the steam turbine 101 (low-pressure steam turbine 106).

[0049] In a steam turbine system 100 according to one embodiment, the steam turbine 101 is preferably configured to be supplied with steam generated by a steam generator (waste heat recovery boiler 5). The steam generator (waste heat recovery boiler 5) includes a heat transfer medium passage (exhaust gas passage 18) through which a heat transfer medium flows, a first economizer (first low-pressure economizer 22) provided in the heat transfer medium passage (exhaust gas passage 18), a second economizer (second low-pressure economizer 24) provided upstream of the first economizer (first low-pressure economizer 22) in the heat transfer medium passage (exhaust gas passage 18) in the direction of heat transfer medium flow, a first evaporator (low-pressure evaporator 26) provided upstream of the second economizer (second low-pressure economizer 24) in the direction of heat transfer medium flow, and a heat transfer medium passage (exhaust gas passage 18) The system preferably includes a first superheater (low-pressure superheater 28) located upstream of the first evaporator (low-pressure evaporator 26) in the flow direction, a second evaporator (ultra-low-pressure evaporator 121) located upstream of the first economizer (first low-pressure economizer 22) and downstream of the second economizer (second low-pressure economizer 24) in the heat transfer medium flow direction in the heat transfer medium flow path (exhaust gas flow path 18), and a second superheater (ultra-low-pressure superheater 123) located upstream of the second evaporator (ultra-low-pressure evaporator 121) and downstream of the second economizer (second low-pressure economizer 24) in the heat transfer medium flow direction in the heat transfer medium flow path (exhaust gas flow path 18). The main steam supply line (intermediate-pressure exhaust line 110) is preferably connected to the first superheater (low-pressure superheater 28). The intermediate steam supply line (low-pressure intermediate steam supply line 57) is preferably connected to the second superheater (ultra-low-pressure superheater 123). This allows for the supply of steam at a lower pressure to the intermediate stage than the main steam supplied to the main steam supply line (intermediate pressure exhaust line 110), thereby improving the efficiency of the steam turbine system 100.

[0050] (Regarding other embodiments) Figure 2 shows a schematic configuration of a part of the combined plant 2(2B) according to another embodiment. In addition, the combined plant 2B according to other embodiments has the same configuration as the combined plant 2A according to one embodiment shown in Figure 1, except for the points described below. In the combined plant 2B according to other embodiments, components that are the same as those in the combined plant 2A according to one embodiment shown in Figure 1 are denoted by the same reference numerals as in the combined plant 2A according to one embodiment, and detailed explanations may be omitted.

[0051] Although omitted in Figure 1 to avoid diagrammatic complexity, the steam turbine system 100A according to one embodiment shown in Figure 1, and the steam turbine system 100(100B) according to another embodiment shown in Figure 2, are equipped with a gland steam supply line 130 for guiding steam to a high-pressure gland section 102b that reduces steam leakage from the turbine body 102a of the high-pressure steam turbine 102 to the outside, and to a medium-pressure gland section 104b that reduces steam leakage from the turbine body 104a of the medium-pressure steam turbine 104 to the outside.

[0052] In the steam turbine system 100B according to another embodiment, unlike the steam turbine system 100A according to one embodiment shown in Figure 1, there is a branch line 131 (intermediate stage steam supply line) that is branched off from the gland steam supply line 130. The branch line 131 connects the gland steam supply line 130 to the intermediate stage of the low-pressure steam turbine 106. Therefore, a portion of the steam flowing through the gland steam supply line 130 is supplied to the intermediate stage of the low-pressure steam turbine 106 via the branch line 131.

[0053] In the steam turbine system 100B according to another embodiment, unlike the steam turbine system 100A according to one embodiment shown in Figure 1, the chemical injection device 150 is configured to inject chemicals from the chemical tank 151 into the branch line 131 via the chemical injection line 155. That is, in the steam turbine system 100B according to another embodiment, unlike the steam turbine system 100A according to one embodiment shown in Figure 1, the chemical injection line 155 is connected to the branch line 131. In the steam turbine system 100B according to another embodiment, the chemicals pumped by the chemical injection pump 153 are supplied together with the steam flowing through the branch line 131 to the main flow path through which the main steam flows inside the low-pressure steam turbine 106. Furthermore, a mixing section 158 may be provided at the connection point between the drug injection line 155 and the branch line 131 for mixing the drug from the drug injection line 155 with the steam flowing through the branch line 131.

[0054] In the steam turbine system 100B according to another embodiment, the intermediate stage steam supply line (branch line 131) may be configured to supply steam extracted from equipment other than the low-pressure steam turbine 106. This allows steam extracted from equipment other than the low-pressure steam turbine 106 to be supplied to the intermediate stage of the low-pressure steam turbine 106. Furthermore, the equipment other than the low-pressure steam turbine 106 mentioned above refers to, for example, the auxiliary boiler (not shown) of the combined plant 2 if the gland steam supplied to the high-pressure gland section 102b or the intermediate-pressure gland section 104b is steam extracted from the high-pressure steam turbine 102 or the intermediate-pressure steam turbine 104.

[0055] Thus, in the steam turbine system 100B according to another embodiment, the branch line 131 (intermediate stage steam supply line) branches off from the gland steam supply line 130 and is configured to supply steam from the gland steam supply line 130 to the intermediate stage of the low-pressure steam turbine 106. This allows the efficiency of the steam turbine system 100B to be improved by supplying steam from the gland steam supply line 130 to the intermediate stage of the low-pressure steam turbine 106.

[0056] In addition, in the steam turbine system 100B according to another embodiment, the waste heat recovery boiler 5 may be a triple-pressure system having a high-pressure system, an intermediate-pressure system, and a low-pressure system. Furthermore, in the steam turbine system 100B according to another embodiment, the waste heat recovery boiler 5 may be a quadruple-pressure system having a high-pressure system, an intermediate-pressure system, a low-pressure system, and an ultra-low-pressure system. In this case, unlike the steam turbine system 100A according to one embodiment shown in Figure 1, the chemical injection device 150 in the steam turbine system 100B according to another embodiment may be configured to inject the chemical in the chemical tank 151 into the branch line 131 via the chemical injection line 155.

[0057] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate. For example, the waste heat recovery boiler 5 according to the above-described embodiment is a quadruple-pressure system having a high-pressure system, a medium-pressure system, a low-pressure system, and an ultra-low-pressure system, but it may also be a single-pressure system, a double-pressure system, or a triple-pressure system. Similarly, the waste heat recovery boiler 5 according to the other embodiments described above may be a single-pressure system or a double-pressure system, in addition to the triple-pressure system or quadruple-pressure system described above. Furthermore, if the waste heat recovery boiler 5 according to some of the embodiments described above is a double-pressure type, the chemical injection device 150 is preferably configured to inject the chemical into the intermediate stage of the furthest downstream steam turbine 101.

[0058] In some of the embodiments described above, the chemicals pumped by the chemical injection pump 153 are supplied together with the steam flowing through the low-pressure intermediate steam supply line 57 or the branch line 131 to the main flow path through which the main steam flows inside the low-pressure steam turbine 106. However, as will be explained below, the chemical pumped by the chemical injection pump 153 may be supplied directly into the stator blades of the steam turbine 101 (low-pressure steam turbine 106) and supplied from the surface of the stator blades into the main flow path through which the main steam flows inside the steam turbine 101 (low-pressure steam turbine 106).

[0059] Figure 3A is a schematic side view of the stator blade 170 (170A) of the steam turbine 101 (low-pressure steam turbine 106). Figure 3B is a schematic diagram showing the cross-section taken along the line III-III in Figure 3A. In the stationary vane 170A shown in Figures 3A and 3B, a drug flow hole 173 is provided inside the airfoil portion 171, extending from the base to the tip of the airfoil portion 171 along the entire length in the wing height direction. In the stationary vane 170A shown in Figures 3A and 3B, the flow holes 173 are formed near the pressure surface 171a of the airfoil portion 171 and near the leading edge 172.

[0060] In the stationary vane 170A shown in Figures 3A and 3B, within the pressure surface 171a, a plurality of through holes 174 communicating with the flow hole 173 are formed on the pressure surface 171a side near the leading edge 172, extending along the direction of extension of the flow hole 173 and covering the entire vane height direction. The openings 174a on the exit side (wing surface) of the multiple through holes 174 are preferably formed such that their width gradually increases along the wing height direction as they move toward the trailing edge 175.

[0061] The flow holes 173 and the multiple through holes 174 may be provided in all the stationary blades 170 in either the intermediate stage or the downstream stage of the steam turbine 101 (low-pressure steam turbine 106).

[0062] In the stationary vane 170A shown in Figures 3A and 3B, it is preferable that the drug pumped by the drug injection pump 153 is directly supplied to the flow port 173. The supply flow rate of the drug can be controlled by adjusting the supply pressure to the flow port 173.

[0063] Figure 4A is a schematic side view of the stator blade 170 (170B) of the steam turbine 101 (low-pressure steam turbine 106). Figure 4B is a schematic diagram showing the cross-section taken along the line IV-IV in Figure 4A. As shown in Figures 4A and 4B, the stationary vane 170B may have the flow holes 173 and the multiple through holes 174 formed near the negative pressure surface 171b and near the leading edge 172 of the airfoil portion 171.

[0064] Figure 5 is a schematic side view of the stator blade 170 (170C) of the steam turbine 101 (low-pressure steam turbine 106). In the stator vane 170A shown in Figures 3A and 3B, or the stator vane 170B shown in Figures 4A and 4B, the flow holes 173 and the multiple through holes 174 may be arranged in multiple rows at different positions along the steam flow direction, as in the stator vane 170C shown in Figure 5. In this case, the positions in the blade height direction of multiple through holes 174 adjacent to each other in the steam flow direction should be different from each other.

[0065] Figure 6A is a schematic side view of the stator blade 170 (170D) of the steam turbine 101 (low-pressure steam turbine 106). Figure 6B is a schematic diagram showing the cross-section taken along the line VI-VI in Figure 6A. In the stationary blade 170D shown in Figures 6A and 6B, the chemical agent can be supplied from the flow hole 173 through the porous body 176 to the main flow path inside the steam turbine 101 (low-pressure steam turbine 106). The porous body 176 is preferably extended over the entire airfoil height direction from the base to the tip of the airfoil portion 171. The porous body 176 can be formed by additive manufacturing or the like. In the stationary vane 170 shown in Figures 3A, 3B, 4A, 4B, and 5, instead of supplying the chemical agent to the main flow path inside the steam turbine 101 (low-pressure steam turbine 106) through multiple through-holes 174, it may be supplied via a porous body 176.

[0066] The contents described in each of the above embodiments can be understood, for example, as follows: (1) A steam turbine system 100 according to at least one embodiment of the present disclosure includes a steam turbine 101 (low-pressure steam turbine 106), a main steam supply line (intermediate-pressure exhaust line 110) for supplying steam to the uppermost stage of the steam turbine 101 (low-pressure steam turbine 106), an intermediate stage steam supply line (low-pressure intermediate stage steam supply line 57, branch line 131) for supplying steam to an intermediate stage downstream of the uppermost stage of the steam turbine 101 (low-pressure steam turbine 106), and a chemical injection device 150 for injecting chemicals to reform steam into the intermediate stage steam supply line (low-pressure intermediate stage steam supply line 57, branch line 131).

[0067] According to the configuration described in (1) above, by supplying steam to which a steam reforming agent has been added to the intermediate stage of the steam turbine 101 (low-pressure steam turbine 106), in addition to improving the efficiency of the steam turbine system 100 by supplying steam to the intermediate stage, the aforementioned braking losses can be suppressed by making the droplets generated in the steam turbine 101 (low-pressure steam turbine 106) finer. This makes it possible to improve the efficiency of the steam turbine system 100.

[0068] (2) In some embodiments, in the configuration of (1) above, the steam turbine 101 may include a high-pressure steam turbine 102, an intermediate-pressure steam turbine 104, and a low-pressure steam turbine 106. The intermediate stage steam supply line may include a low-pressure intermediate stage steam supply line 57 for supplying steam to the intermediate stage of the low-pressure steam turbine 106. The chemical injection device 150 may be capable of injecting chemicals into the low-pressure intermediate stage steam supply line 57.

[0069] According to the configuration described in (2) above, steam to which a steam reforming agent has been added is supplied to the intermediate stage and beyond of the low-pressure steam turbine 106, where there is a high possibility that some of the steam will condense and exist in the airflow as fine water droplets. This makes it possible to efficiently refine the droplets generated within the low-pressure steam turbine 106.

[0070] (3) In some embodiments, in the configuration of (1) or (2) above, the intermediate stage may be the downstream stage of the steam turbine (low-pressure steam turbine 106), or the stage one stage upstream of the downstream stage.

[0071] According to the configuration described in (3) above, steam to which a steam reforming agent has been added is supplied to the downstream stage, or to the stage one stage upstream of the downstream stage, where there is a high possibility that some of the steam has condensed and exists in the airflow as fine water droplets. This makes it possible to efficiently refine the droplets generated in the steam turbine (low-pressure steam turbine 106).

[0072] (4) In some embodiments, in any of the configurations (1) to (3) above, the intermediate stage steam supply line (low-pressure intermediate stage steam supply line 57) may be a steam line branched from the main steam supply line through which steam or water circulates to the steam turbine 101 (low-pressure steam turbine 106), condenser 108, and heat exchanger 20, for supplying steam to the upstream stage of the steam turbine 101 (low-pressure steam turbine 106).

[0073] According to the configuration in (4) above, the steam turbine 101 (low-pressure steam turbine 106), condenser 108, and heat exchanger 20, which supply steam to the upstream stage of the steam turbine 101 (low-pressure steam turbine 106), can be supplied to the intermediate stage from a steam line branched from the main steam supply line through which steam or water circulates.

[0074] (5) In some embodiments, in any of the configurations (1) to (4) above, the steam turbine 101 is preferably configured to be supplied with steam generated by the steam generator (heat recovery boiler 5). The steam generator (heat recovery boiler 5) includes a heat transfer medium passage (exhaust gas passage 18) through which the exhaust gas of the gas turbine 4 flows as a heat transfer medium, a first economizer (first low-pressure economizer 22) provided in the heat transfer medium passage (exhaust gas passage 18), a second economizer (second low-pressure economizer 24) provided upstream of the first economizer (first low-pressure economizer 22) in the heat transfer medium passage (exhaust gas passage 18) in the direction of heat transfer medium flow, a first evaporator (low-pressure evaporator 26) provided upstream of the second economizer (second low-pressure economizer 24) in the direction of heat transfer medium flow, and the heat transfer medium passage (exhaust gas passage 18) The system preferably includes a first superheater (low-pressure superheater 28) located upstream of the first evaporator (low-pressure superheater 26) in the direction of heat transfer fluid flow, a second evaporator (ultra-low-pressure evaporator 121) located upstream of the first economizer (first low-pressure economizer 22) and downstream of the second economizer (second low-pressure economizer 24) in the direction of heat transfer fluid flow in the heat transfer fluid flow path (exhaust gas flow path 18), and a second superheater (ultra-low-pressure superheater 123) located upstream of the second evaporator (ultra-low-pressure evaporator 121) and downstream of the second economizer (second low-pressure economizer 24) in the direction of heat transfer fluid flow in the heat transfer fluid flow path (exhaust gas flow path 18). The main steam supply line (intermediate-pressure exhaust line 110) is preferably connected to the first superheater (low-pressure superheater 28). The intermediate steam supply line (low-pressure intermediate steam supply line 57) is preferably connected to the second superheater (ultra-low-pressure superheater 123).

[0075] According to the configuration described in (5) above, the efficiency of the steam turbine system 100 can be improved by supplying steam at a lower pressure than the main steam supplied to the main steam supply line (intermediate pressure exhaust line 110) to the intermediate stage.

[0076] (6) In some embodiments, in any of the configurations (1) to (3) above, the steam turbine 101 may include a high-pressure steam turbine 102, an intermediate-pressure steam turbine 104, and a low-pressure steam turbine 106. In some embodiments, the intermediate steam supply line (branch line 131) may be configured to supply steam extracted from equipment other than the low-pressure steam turbine 106.

[0077] According to the configuration described in (6) above, steam extracted from equipment other than the low-pressure steam turbine 106 can be supplied to the intermediate stage.

[0078] (7) In some embodiments, in the configuration of (1) or (6) above, the steam turbine 101 may include a high-pressure steam turbine 102, an intermediate-pressure steam turbine 104, and a low-pressure steam turbine 106. In some embodiments, the steam turbine system 100 may include a gland steam supply line 130 for supplying steam to a high-pressure gland section 102b that reduces steam leakage from the turbine body 102a of the high-pressure steam turbine 102 to the outside, and to an intermediate-pressure gland section 104b that reduces steam leakage from the turbine body 104a of the intermediate-pressure steam turbine 104 to the outside. The intermediate stage steam supply line (branch line 131) is preferably branched from the gland steam supply line 130 and configured to supply steam from the gland steam supply line 130 to the intermediate stage of the low-pressure steam turbine 106.

[0079] According to the configuration described in (7) above, the efficiency of the steam turbine system 100 can be improved by supplying steam from the gland steam supply line 130 to the intermediate stage of the low-pressure steam turbine 106. [Explanation of symbols]

[0080] 2 (2A, 2B) Combined Plant 5. Waste heat recovery boiler 18. Exhaust gas flow path (heat transfer medium flow path) 22. First Low-Pressure Emulsifier (First Emulsifier) 24. Second Low-Pressure Emulsifier (Second Emulsifier) 26. Low-pressure evaporator (first evaporator) 28. Low-pressure superheater (first superheater) 57. Low-pressure intermediate steam supply line (intermediate steam supply line) 100 (100A, 100B) Steam Turbine System 101 Steam Turbine 102 High-pressure steam turbine 104 Medium-Pressure Steam Turbine 106 Low-pressure steam turbine 110 Medium-pressure exhaust line 121. Ultra-low pressure evaporator (second evaporator) 123. Ultra-low pressure superheater (second superheater) 131 Branch line (intermediate steam supply line) 150 Drug infusion device 200 Waste Heat Recovery Plant

Claims

1. Multiple steam turbines, A main steam supply line for supplying steam to the steam inlet of the downstream steam turbine among the aforementioned plurality of steam turbines, An intermediate stage steam supply line for supplying steam to the intermediate stage downstream of the steam inlet of the downstreammost steam turbine, A chemical injection device for injecting a chemical agent for reforming steam into the aforementioned intermediate steam supply line, Equipped with, The aforementioned agent is an agent that atomizes the droplets generated by the condensation of steam in the downstream steam turbine. Steam turbine system.

2. The plurality of steam turbines include a high-pressure steam turbine, an intermediate-pressure steam turbine, and a low-pressure steam turbine. The downstream steam turbine is the low-pressure steam turbine. The steam turbine system according to claim 1.

3. The agent is a volatile amine compound having volatility, surfactant properties, and corrosion-preventive properties. The steam turbine system according to claim 1 or 2.

4. The aforementioned chemical injection device includes at least one of volatile amine compounds, volatile nonamine compounds, and polyamines as a chemical agent for miniaturizing the droplets generated in the steam turbine. The steam turbine system according to claim 1 or 2.

5. The intermediate stage steam supply line includes a low-pressure intermediate stage steam supply line for supplying steam to the intermediate stage of the low-pressure steam turbine. The chemical injection device is capable of injecting the chemical into the low-pressure intermediate steam supply line. The steam turbine system according to claim 2.

6. The aforementioned intermediate stage is the downstreammost stage of the downstream steam turbine, or the stage one stage upstream of the downstreammost stage. The steam turbine system according to claim 1 or 2.

7. The steam turbine system according to claim 1 or 2, characterized in that the intermediate steam supply line is branched from the main steam supply line.

8. Steam turbine and A main steam supply line for supplying steam to the upstream stage of the steam turbine, An intermediate stage steam supply line for supplying steam to the intermediate stage downstream of the upstream stage of the steam turbine, A chemical injection device for injecting a chemical agent for reforming steam into the aforementioned intermediate steam supply line, Equipped with, The steam turbine is configured to receive steam generated by a steam generator, The steam generator is, A heat transfer fluid channel through which the heat transfer fluid flows, A first section charcoal is provided in the heat transfer medium flow path, In the heat transfer medium flow path, a second eclipse is provided on the upstream side of the first eclipse in the flow direction of the heat transfer medium, In the heat transfer medium flow path, a first evaporator is provided on the upstream side of the second economizer in the flow direction of the heat transfer medium, In the heat transfer medium flow path, a first superheater is provided on the upstream side of the first evaporator in the flow direction of the heat transfer medium, In the heat transfer medium flow path, a second evaporator is provided upstream of the first economizer and downstream of the second economizer in the flow direction of the heat transfer medium, In the heat transfer medium flow path, a second superheater is provided upstream of the second evaporator and downstream of the second economizer in the flow direction of the heat transfer medium, Includes, The main steam supply line is connected to the first superheater, The intermediate steam supply line is connected to the second superheater. Steam turbine system.

9. The steam turbine system according to claim 2, wherein the intermediate steam supply line supplies steam extracted from equipment other than the low-pressure steam turbine.

10. Steam turbine and A main steam supply line for supplying steam to the upstream stage of the steam turbine, An intermediate stage steam supply line for supplying steam to the intermediate stage downstream of the upstream stage of the steam turbine, A chemical injection device for injecting a chemical agent for reforming steam into the aforementioned intermediate steam supply line, Equipped with, The steam turbine includes a high-pressure steam turbine, an intermediate-pressure steam turbine, and a low-pressure steam turbine. A gland steam supply line for guiding steam to a high-pressure gland section that reduces steam leakage from the turbine body of the high-pressure steam turbine to the outside, and to a medium-pressure gland section that reduces steam leakage from the turbine body of the medium-pressure steam turbine to the outside, Equipped with, The aforementioned intermediate stage steam supply line branches off from the gland steam supply line and is configured to supply steam from the gland steam supply line to the intermediate stage of the low-pressure steam turbine. Steam turbine system.

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