阅读说明：本技术 中排抽汽喷水供热系统及方法 (Medium-exhaust steam-extraction water-spraying heat supply system and method ) 是由 蒋晓锋 尤鸿燕 马欣敏 吴明州 王璞 何翔 朱一飞 于 2020-06-30 设计创作，主要内容包括：本发明涉及火电机组技术领域,尤其涉及一种中排抽汽喷水供热系统,包括中压缸、低压缸、除氧器、减温器和换热器,中压缸的排汽口连接低压缸的进汽口,减温器的进汽口和进水口分别连接中压缸的排汽口和除氧器的出口,减温器的出口连接换热器的热端进口,换热器的热端出口连接除氧器的进口,换热器的冷端进口和冷端出口分别连接热网回水管和热网供水管。还涉及一种中排抽汽喷水供热方法,抽取中压缸排汽口排出的蒸汽,并将抽取的蒸汽与除氧器出口排出的给水在减温器内混合,使抽取的蒸汽温度降低,再将减温器内混合后的蒸汽送入换热器内与热网回水换热。能够提高供热量和经济性。(The invention relates to the technical field of thermal power generating units, in particular to a medium-exhaust steam-extraction water-spraying heat supply system which comprises a medium-pressure cylinder, a low-pressure cylinder, a deaerator, a desuperheater and a heat exchanger, wherein a steam exhaust port of the medium-pressure cylinder is connected with a steam inlet of the low-pressure cylinder, a steam inlet and a water inlet of the desuperheater are respectively connected with a steam exhaust port of the medium-pressure cylinder and an outlet of the deaerator, an outlet of the desuperheater is connected with a hot end inlet of the heat exchanger, a hot end outlet of the heat exchanger is connected with an inlet of the deaerator, and a cold end inlet and a cold end. The extracted steam is mixed with feed water discharged from an outlet of a deaerator in a desuperheater to reduce the temperature of the extracted steam, and the mixed steam in the desuperheater is sent into a heat exchanger to exchange heat with return water of a heat supply network. Can improve the heat supply and the economy.)

1. A middle-exhaust steam-extraction water-spraying heat supply system is characterized by comprising a middle-pressure cylinder (1), a low-pressure cylinder (2), a deaerator (3), a desuperheater (4) and a heat exchanger (5), the steam outlet (1a) of the intermediate pressure cylinder (1) is connected with the steam inlet (2a) of the low pressure cylinder (2), a steam inlet (4a) and a water inlet (4b) of the desuperheater (4) are respectively connected with a steam outlet (2b) of the intermediate pressure cylinder (1) and an outlet (3b) of the deaerator (3), an outlet (4c) of the desuperheater (4) is connected with a hot end inlet (5a) of the heat exchanger (5), a hot end outlet (5b) of the heat exchanger (5) is connected with an inlet (3a) of the deaerator (3), and a cold end inlet (5c) and a cold end outlet (5d) of the heat exchanger (5) are respectively connected with a heat supply network water return pipe (7) and a heat supply network water supply pipe (8).

2. A medium extraction steam-injection water-heating system according to claim 1, characterized in that the outlet (3b) of the deaerator (3) is connected to the water inlet (4b) of the desuperheater (4) through a water feed pump (9).

3. A medium extraction hydrojet heating system as claimed in claim 2, in which the outlet (9b) of the feedwater pump (9) is connected to the inlet (4b) of the desuperheater (4) by means of a regulating valve.

4. A medium extraction steam-spray water heating system according to claim 1, characterized in that the hot end outlet (5b) of the heat exchanger (5) is connected with the inlet (3a) of the deaerator (3) through a drain pump (10).

5. A medium extraction steam-injection water heating system according to claim 1, characterised in that the heat network return pipe (7) is connected to the cold end inlet (5c) of the heat exchanger (5) by a heat network water circulation pump (11).

6. A middle-exhaust steam-extraction water-spraying heat supply method is characterized in that steam exhausted from a steam outlet (1a) of a middle pressure cylinder (1) is extracted, the extracted steam is mixed with water supply exhausted from an outlet (3b) of a deaerator (3) in a desuperheater (4) to reduce the temperature of the extracted steam, and the mixed steam in the desuperheater (4) is sent into a heat exchanger (5) to exchange heat with return water of a heat supply network; and the steam outlet (1a) of the intermediate pressure cylinder (1) is connected with the steam inlet (2a) of the low pressure cylinder (2).

Technical Field

The invention relates to the technical field of thermal power generating units, in particular to a medium-exhaust steam extraction water-spraying heat supply system and a medium-exhaust steam extraction water-spraying heat supply method.

Background

The thermal power generating unit is used for steam extraction and heating transformation, and the improvement range of the economy of the thermal power generating unit is related to multiple factors such as steam extraction parameters, steam extraction quantity and steam extraction position. On the premise of the same heat supply requirement, the key point of researching a thermodynamic system is to select an extraction scheme which is suitable for a unit and has the maximum economical efficiency.

The urban heating pipeline generally adopts liquid water as a heating medium, and the water temperature is below 150 ℃. The steam extraction parameters of the thermal power generating unit are higher than the parameters required by a heating pipeline and cannot be directly used for heating, so that a heating station is usually required to be arranged to connect the steam extraction pipeline and the heating pipeline. High-temperature high-pressure steam in the steam extraction pipeline exchanges heat with return water of a heating pipeline in the heating station, and the return water is heated and then conveyed to a heat supply network user for use, so that heating is realized. The heat supply amount of the steam extraction heat supply mode is limited by the maximum steam extraction amount which can be borne by a heat supply steam pipeline (namely a steam extraction pipeline). Under the condition that the caliber of the heat supply steam pipeline is fixed, the maximum steam extraction amount of the heat supply steam pipeline is limited by the steam flow rate. The heat supply is thus limited by the steam flow rate. Therefore, the machine set only extracts the exhaust steam of the intermediate pressure cylinder to supply heat or uses low-temperature desuperheating water to supply heat has the defect of insufficient heat supply capacity of the system.

Disclosure of Invention

The invention aims to provide a medium-exhaust steam-extraction water-spraying heat supply system and a medium-exhaust steam-extraction water-spraying heat supply method, which can improve heat supply and economy and overcome the defects in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

the utility model provides a well row steam extraction water spray heating system, includes intermediate pressure jar, low pressure jar, the oxygen-eliminating device, desuperheater and heat exchanger, the steam inlet of low pressure jar is connected to the steam exhaust mouth of intermediate pressure jar, the steam inlet and the water inlet of desuperheater are connected the steam exhaust mouth of intermediate pressure jar and the export of oxygen-eliminating device respectively, the exit linkage heat junction import of heat exchanger of desuperheater, the import of the hot junction exit linkage oxygen-eliminating device of heat exchanger, the cold junction import and the cold junction export of heat exchanger are connected heat supply network wet return and heat supply network delivery pipe respectively.

Preferably, the outlet of the deaerator is connected with the water inlet of the desuperheater through a water feeding pump.

Preferably, the outlet of the feed water pump is connected with the water inlet of the desuperheater through the regulating valve.

Preferably, the hot end outlet of the heat exchanger is connected with the inlet of the deaerator through a drain pump.

Preferably, the heat supply network water return pipe is connected with the cold end inlet of the heat exchanger through a heat supply network water circulating pump.

A middle-exhaust steam-extraction water-spraying heat supply method comprises the steps of extracting steam exhausted from a steam exhaust port of a middle pressure cylinder, mixing the extracted steam with feed water exhausted from an outlet of a deaerator in a desuperheater to reduce the temperature of the extracted steam, and sending the mixed steam in the desuperheater into a heat exchanger to exchange heat with return water of a heat supply network; the steam outlet of the intermediate pressure cylinder is connected with the steam inlet of the low pressure cylinder.

Compared with the prior art, the invention has the remarkable progress that:

compared with the prior art that the medium-pressure steam is directly sent into the heat exchange device through the heat supply steam pipeline to exchange heat with the return water of the heat supply network, the extracted medium-pressure cylinder steam exhaust and the water supply discharged from the outlet of the deaerator are mixed in the desuperheater to form heat supply steam with the temperature lower than the medium-pressure steam exhaust temperature, then the heat supply steam is sent into the heat exchanger through the heat supply steam pipeline to exchange heat with the return water of the heat supply network to heat the return water of the heat supply network, the temperature of the medium-pressure steam exhaust is reduced by utilizing the water supply discharged from the outlet of the deaerator, on one hand, the temperature of the heat supply steam in the heat supply steam pipeline is reduced, the steam flow rate of unit heat supply is reduced, the maximum steam extraction amount is increased, the heat supply amount to the heat exchanger can be increased, namely, the heat supply amount to users of the heat supply network is increased, the working; on the other hand, the temperature of the feed water discharged from the outlet of the deaerator is higher than the temperature of the return water discharged from the water outlet of the heat supply network user, so that the feed water at the outlet of the deaerator and the intermediate exhaust steam are mixed to form heat supply steam, namely, the feed water at the outlet of the deaerator and the intermediate exhaust steam are added to be used as heat supply sources, and the heat supply is jointly supplied to the heat exchanger by the feed water at the outlet of the deaerator and the intermediate exhaust steam to heat the return water of the heat supply network, so that the actual steam extraction amount of the intermediate pressure cylinder can be reduced, the work loss of the steam.

Drawings

Fig. 1 is a simplified schematic diagram of a steam extraction and water injection heating system according to an embodiment of the present invention.

Wherein the reference numerals are as follows:

1. steam exhaust port of intermediate pressure cylinder 1a and intermediate pressure cylinder

2. Steam inlet of low pressure cylinder 2a and low pressure cylinder

2b, a steam outlet 3 of the low-pressure cylinder and a deaerator

3a, an inlet 3b of a deaerator and an outlet of the deaerator

4. Desuperheater 4a, inlet of desuperheater

4b, a water inlet 4c of the desuperheater and an outlet of the desuperheater

5. Heat exchanger 5a, hot end inlet of heat exchanger

5b, hot end outlet 5c of the heat exchanger and cold end inlet of the heat exchanger

5d, cold end outlet 6 of heat exchanger, and high-pressure cylinder

7. Heat supply network water return pipe 8 and heat supply network water supply pipe

9. Feed pump 9a, inlet of feed pump

9b, outlet 10 of feed pump, and drain pump

10a, an inlet 10b of the hydrophobic pump, an outlet of the hydrophobic pump

11. Heat supply network water circulating pump 11a and heat supply network water circulating pump inlet

11b, outlet of heat supply network water circulating pump

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present invention and are not intended to limit the present invention.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

As shown in fig. 1, an embodiment of the present invention provides a medium-extraction steam-extraction water-injection heating system. The medium-exhaust steam-extraction water-spraying heat supply system of the embodiment comprises a medium-pressure cylinder 1, a low-pressure cylinder 2, a deaerator 3, a desuperheater 4 and a heat exchanger 5, and in addition, the medium-exhaust steam-extraction water-spraying heat supply system of the embodiment can further comprise a boiler (not shown in the figure), a high-pressure cylinder 6 and a condenser (not shown in the figure).

Wherein, the steam outlet of boiler connects the steam inlet of high pressure jar 6, the reheat steam import of boiler is connected to the steam exhaust mouth of high pressure jar 6, the reheat steam exit linkage steam inlet of 1 of intermediate pressure jar of boiler, steam exhaust mouth 1a of intermediate pressure jar 1 connects steam inlet 2a of 2 low pressure jars, the steam exhaust mouth 2b of 2 low pressure jars passes through the import 3a that the condenser is connected to the oxygen-eliminating device 3, the import of the steam exhaust mouth connection condenser of 2 low pressure jars promptly, the import 3a of the exit linkage oxygen-eliminating device 3 of condenser, the import of the boiler is connected to the export 3b of oxygen-eliminating device 3. High-temperature high-pressure steam in the boiler is introduced into a steam inlet of a high-pressure cylinder 6 from a steam outlet of the boiler to do work in the high-pressure cylinder 6, the steam which does work in the high-pressure cylinder 6 is discharged from a steam outlet of the high-pressure cylinder 6 and introduced into a reheat steam inlet of the boiler to be reheated and heated, then the steam which does work in the high-pressure cylinder 6 is introduced into a steam inlet of an intermediate-pressure cylinder 1 from a reheat steam outlet of the boiler to enter the intermediate-pressure cylinder 1 to do work, the steam which does work in the intermediate-pressure cylinder 1 is discharged from a steam outlet 1a of the intermediate-pressure cylinder 1 and introduced into a steam inlet 2a of a low-pressure cylinder 2 to enter the low-pressure cylinder 2 to do work, the steam which does work in the low-pressure cylinder 2 is discharged from a steam outlet of the low-pressure cylinder 2 and introduced into an inlet of a condenser to be condensed into water in the condenser, the condensed water in the condenser is discharged from an outlet of the condenser and introduced into an inlet 3a deaerator 3 to be deaerated in the deaerated, and enters the boiler as boiler feed water.

The desuperheater 4 has a steam inlet 4a, a water inlet 4b and an outlet 4 c. The steam inlet 4a of the desuperheater 4 is connected with the steam outlet 1a of the intermediate pressure cylinder 1, so that part of the steam exhausted by the intermediate pressure cylinder 1 enters the desuperheater 4 as extracted steam, namely, the extracted steam is introduced into the desuperheater 4 through a steam extraction pipeline. The water inlet 4b of the desuperheater 4 is connected with the outlet 3b of the deaerator 3, so that part of the feed water discharged from the outlet 3b of the deaerator 3 is introduced into the desuperheater 4. The well extraction steam and the 3b of oxygen-eliminating device export 3b feedwater that let in the desuperheater 4 mix in the desuperheater 4, because the export 3b exhaust feedwater temperature of oxygen-eliminating device 3 will be less than the exhaust steam temperature of intermediate pressure jar 1, consequently, the temperature of the extraction steam of can reducing after feedwater mixes with well extraction steam in the desuperheater 4, and the heat evaporation steam of extraction steam in the feed water then absorbs, mixes with well extraction steam and forms the heat supply steam, this heat supply steam is discharged from the export 4c of desuperheater 4.

The heat exchanger 5 is provided with a hot end inlet 5a, a hot end outlet 5b, a cold end inlet 5c and a cold end outlet 5d, the hot end inlet 5a and the hot end outlet 5b of the heat exchanger 5 are communicated to form a hot end channel, and the cold end inlet 5c and the cold end outlet 5d of the heat exchanger 5 are communicated to form a cold end channel. An outlet 4c of the desuperheater 4 is connected with a hot end inlet 5a of the heat exchanger 5, a hot end outlet 5b of the heat exchanger 5 is connected with an inlet 3a of the deaerator 3, a cold end inlet 5c of the heat exchanger 5 is connected with a heat supply network water return pipe 7, the heat supply network water return pipe 7 is connected with a water outlet of a heat supply network user, a cold end outlet 5d of the heat exchanger 5 is connected with a heat supply network water supply pipe 8, and the heat supply network water supply pipe 8 is connected with a water inlet. The heating steam discharged from the outlet 4c of the desuperheater 4 enters from the hot end inlet 5a of the heat exchanger 5 and flows through the hot end channel of the heat exchanger 5, and the connecting pipeline between the outlet 4c of the desuperheater 4 and the hot end inlet 5a of the heat exchanger 5 is a heating steam pipeline; and the return water discharged from the water outlet of the heat supply network user is sent into a heat supply network return water pipe 7, and the return water in the heat supply network return water pipe 7 enters from a cold end inlet 5c of the heat exchanger 5 and flows through a cold end channel of the heat exchanger 5. The heat supply steam and the return water carry out heat exchange when respectively flowing through the hot end channel and the cold end channel of the heat exchanger 5, and respectively release and absorb heat. The heat supply steam is condensed into water after releasing heat, the condensed water is discharged from a hot end outlet 5b of the heat exchanger 5 and is introduced into an inlet 3a of the deaerator 3, and the condensed water is sent into the deaerator 3 to be deaerated and then is also discharged from an outlet 3b of the deaerator 3 as feed water. The temperature of the backwater is raised after the heat is absorbed by the backwater to reach the required temperature of the heat supply network, and then the backwater is discharged from a cold end outlet 5d of the heat exchanger 5 and is introduced into a water supply pipe 8 of the heat supply network, and the backwater is sent to a water inlet of a user of the heat supply network for use by the water supply pipe 8 of the heat supply network.

Compared with the prior art that the medium-exhaust steam is directly sent into the heat exchange device through the heat supply steam pipeline to exchange heat with the return water of the heat supply network, the medium-exhaust steam-extraction water-spraying heat supply system of the embodiment mixes the extracted exhaust steam of the medium pressure cylinder 1 and the feed water discharged from the outlet 3b of the deaerator 3 in the desuperheater 4 to form the heat supply steam with the temperature lower than the medium-exhaust steam-extraction temperature, then sends the heat supply steam into the heat exchanger 5 through the heat supply steam pipeline to exchange heat with the return water of the heat supply network to heat the return water of the heat supply network, reduces the temperature of the medium-exhaust steam by utilizing the feed water discharged from the outlet 3b of the deaerator 3, reduces the temperature of the heat supply steam in the heat supply steam pipeline on one hand, reduces the steam flow rate of unit heat supply amount, improves the, the heat supply amount to the heat supply network users is increased, so that the heat supply capacity of the system is improved, the working parameters of equipment are reduced, and the economic investment of equipment construction is reduced; on the other hand, the temperature of the feed water discharged from the outlet 3b of the deaerator 3 is higher than the return water temperature discharged from the water outlet of a heat supply network user, so that the feed water at the outlet 3b of the deaerator 3 is mixed with the middle exhaust steam extraction to form heat supply steam, namely, the feed water at the outlet 3b of the deaerator 3 is added to be used as a heat supply source, and the feed water at the outlet 3b of the deaerator 3 and the middle exhaust steam extraction are used for supplying heat to the heat exchanger 5 together to heat return water of the heat supply network, so that the actual steam extraction amount of the steam discharged by the middle pressure cylinder 1 can be reduced, the work loss of the steam is reduced. The medium-exhaust steam-extraction water-spraying heat supply system has the advantages of good heat supply capacity and economy, reasonable structure, reliable system and high equipment safety.

In this embodiment, preferably, the mode that the feed water at the outlet 3b of the deaerator 3 is introduced into the desuperheater 4 and mixed with the medium-exhaust steam introduced into the desuperheater 4 is water supply spraying medium-exhaust steam, and the spraying mode can enable the medium-exhaust steam introduced into the desuperheater 4 and the feed water at the outlet 3b of the deaerator 3 to be fully mixed in the desuperheater 4, so that the temperature of the medium-exhaust steam is effectively reduced.

In this embodiment, preferably, the outlet 3b of the deaerator 3 may be connected to the water inlet 4b of the desuperheater 4 through a water supply pump 9. The inlet 9a of the feed pump 9 is connected with the outlet 3b of the deaerator 3, and the outlet 9b of the feed pump 9 is simultaneously connected with the inlet of the boiler and the water inlet 4b of the desuperheater 4. The feed water discharged from the outlet 3b of the deaerator 3 is respectively conveyed to the boiler and the desuperheater 4 in two paths under the action of a feed water pump 9.

In this embodiment, the outlet 9b of the feed pump 9 is preferably connected to the inlet 4b of the desuperheater 4 through a regulating valve (not shown). The regulating valve is provided on a pipe connecting the outlet 9b of the feed pump 9 and the water inlet 4b of the desuperheater 4, and is used for regulating the feed water amount fed into the desuperheater 4, that is, regulating the water spraying amount in the desuperheater 4. Parameters of heating steam formed by mixing medium-exhaust steam and water supplied from the outlet 3b of the deaerator 3 can be adjusted by adjusting the water spraying amount in the desuperheater 4, so that the adjustment of parameters of the hot working medium introduced into the heat exchanger 5 is more flexible.

In this embodiment, the hot end outlet 5b of the heat exchanger 5 is preferably connected to the inlet 3a of the deaerator 3 through a hydrophobic pump 10. An inlet 10a of the drain pump 10 is connected with a hot end outlet 5b of the heat exchanger 5, and an outlet 10b of the drain pump 10 is connected with an inlet 3a of the deaerator 3. The condensed water discharged from the hot end outlet 5b of the heat exchanger 5 is conveyed to the deaerator 3 under the action of the drainage pump 10.

In this embodiment, the heat supply network water return pipe 7 is preferably connected to the cold end inlet 5c of the heat exchanger 5 through a heat supply network water circulating pump 11. An inlet 11a of the heat supply network water circulating pump 11 is connected with an outlet of the heat supply network water return pipe 7, and an outlet 11b of the heat supply network water circulating pump 11 is connected with a cold end inlet 5c of the heat exchanger 5. The return water of the heat supply network in the return water pipe 7 of the heat supply network is conveyed to the heat exchanger 5 under the action of the water circulating pump 11 of the heat supply network.

As shown in fig. 1, the embodiment of the present invention further provides a medium-exhaust steam-extraction water-spraying heat supply method. The medium-exhaust steam-extraction water-spraying heat supply method of the embodiment can be realized by adopting the medium-exhaust steam-extraction water-spraying heat supply system of the embodiment. Specifically, the method for supplying heat by exhausting, extracting and spraying steam in the embodiment comprises the following steps: the steam discharged from a steam outlet 1a of the intermediate pressure cylinder 1 is extracted, the extracted steam is mixed with the water supply discharged from an outlet 3b of the deaerator 3 in the desuperheater 4, the temperature of the extracted steam is reduced, the mixed steam in the desuperheater 4 is sent into the heat exchanger 5 through a heat supply steam pipeline to exchange heat with return water of a heat supply network, the return water of the heat supply network is heated, the return water of the heat supply network after being heated in the desuperheater 4 is sent to a water inlet of a heat supply network user to be used, and the steam after heat exchange in the desuperheater 4 is condensed into water and sent into an inlet 3a of the deaerator 3. Wherein, the steam outlet 1a of the intermediate pressure cylinder 1 is connected with the steam inlet 2a of the low pressure cylinder 2, and the steam outlet 2b of the low pressure cylinder 2 is connected with the inlet 3a of the deaerator 3.

Compared with the prior art that the medium-exhaust steam is directly sent into the heat exchange device through the heat supply steam pipeline to exchange heat with the return water of the heat supply network, the medium-exhaust steam-extraction water-spraying heat supply method of the embodiment mixes the extracted exhaust steam of the medium pressure cylinder 1 and the feed water discharged from the outlet 3b of the deaerator 3 in the desuperheater 4 to form the heat supply steam with the temperature lower than the medium-exhaust steam-extraction temperature, then sends the heat supply steam into the heat exchanger 5 through the heat supply steam pipeline to exchange heat with the return water of the heat supply network to heat the return water of the heat supply network, reduces the temperature of the medium-exhaust steam by utilizing the feed water discharged from the outlet 3b of the deaerator 3, reduces the temperature of the heat supply steam in the heat supply steam pipeline on one hand, reduces the steam flow rate of unit heat supply amount, improves the, the heat supply amount to the heat supply network users is increased, so that the heat supply capacity of the system is improved, the working parameters of equipment are reduced, and the economic investment of equipment construction is reduced; on the other hand, the temperature of the feed water discharged from the outlet 3b of the deaerator 3 is higher than the return water temperature discharged from the water outlet of a heat supply network user, so that the feed water at the outlet 3b of the deaerator 3 is mixed with the middle exhaust steam extraction to form heat supply steam, namely, the feed water at the outlet 3b of the deaerator 3 is added to be used as a heat supply source, and the feed water at the outlet 3b of the deaerator 3 and the middle exhaust steam extraction are used for supplying heat to the heat exchanger 5 together to heat return water of the heat supply network, so that the actual steam extraction amount of the steam discharged by the middle pressure cylinder 1 can be reduced, the work loss of the steam is reduced.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions should also be regarded as the protection scope of the present invention.