阅读说明：本技术 一种再热蒸汽联合中排蒸汽加热给水供热系统及方法 (Reheating steam combined middle-exhaust steam heating water supply and heat supply system and method ) 是由 范诚豪 马欣敏 蒋晓锋 陶丽 付涛 曹志贵 于 2019-10-25 设计创作，主要内容包括：本发明提供了一种再热蒸汽联合中排蒸汽加热给水供热系统,包括纯凝汽轮火力发电机组和组合式供热系统；纯凝汽轮火力发电机组主要包括锅炉、汽轮机高压缸、汽轮机中压缸、汽轮机低压缸、高压加热器、除氧器、低压加热器、凝汽器、给水前置泵、汽动给水泵；组合式供热系统主要包括一级表面式给水加热器、蒸汽发生器、二级表面式蒸汽加热器。本发明提供了一种再热蒸汽联合中排蒸汽加热给水供热方法。本发明利用了中排蒸汽的过热度,机组排汽量更小,冷端损失更小,机组效率更高,能级梯度利用更为合理；利用蒸发器代替直接喷水换热,供热参数更稳定,波动小。系统结构合理,系统可靠,负荷适应性好,主机安全性高。(The invention provides a reheating steam combined middle exhaust steam heating water supply and heat supply system, which comprises a straight condensing steam turbine thermal power generator unit and a combined heat supply system; the straight condensing steam turbine thermal power generating unit mainly comprises a boiler, a steam turbine high-pressure cylinder, a steam turbine medium-pressure cylinder, a steam turbine low-pressure cylinder, a high-pressure heater, a deaerator, a low-pressure heater, a condenser, a feed water pre-pump and a steam feed water pump; the combined heating system mainly comprises a primary surface type feedwater heater, a steam generator and a secondary surface type steam heater. The invention provides a method for supplying heat to water by heating exhausted steam in a reheat steam combination. The invention utilizes the superheat degree of the middle exhaust steam, the steam exhaust amount of the unit is smaller, the loss of the cold end is smaller, the unit efficiency is higher, and the energy level gradient utilization is more reasonable; the evaporator is used for replacing direct water spraying heat exchange, so that heat supply parameters are more stable, and fluctuation is small. The system has reasonable structure, reliable system, good load adaptability and high host safety.)

1. The utility model provides a row's steam heating feedwater heating system in reheat steam is united which characterized in that: the system comprises a straight condensing steam turbine thermal power generator unit and a combined type heat supply system;

the pure condensing steam turbine thermal power generating unit comprises a boiler (1), wherein a steam outlet of the boiler (1) is connected with an inlet of a high-pressure steam cylinder (2), an outlet of the high-pressure steam cylinder (2) is connected with a reheat steam inlet of the boiler (1), a reheat steam outlet of the boiler (1) is connected with an inlet of a medium-pressure steam cylinder (3), an outlet of the medium-pressure steam cylinder (3) is connected with an inlet of a low-pressure steam cylinder (4), an outlet of the low-pressure steam cylinder (4) is connected with an inlet of a condenser (8), an outlet of the condenser (8) is connected with an inlet of one side of a low-pressure heater (7), an outlet of the low-pressure heater (7) on the side is connected with an inlet of a deaerator (6), an outlet of the deaerator (6) is connected;

the combined heating system comprises a primary surface type water-feeding heater (11), wherein a low-temperature side inlet of the primary surface type water-feeding heater (11) is connected with an outlet of the deaerator (6), a low-temperature side outlet of the primary surface type water-feeding heater (11) is connected with an inlet of the steam generator (12), a high-temperature side inlet of the primary surface type water-feeding heater (11) is connected with an outlet of the steam turbine intermediate pressure cylinder (3), and a high-temperature side outlet of the primary surface type water-feeding heater (11) is connected with an inlet of the deaerator (6); the outlet of the steam generator (12) is connected with the low-temperature side inlet of the secondary surface type saturated steam heater (13), the high-temperature side inlet of the secondary surface type saturated steam heater (13) is connected with the outlet of the high-pressure cylinder (2) of the steam turbine and/or the inlet of the medium-pressure cylinder (3) of the steam turbine, the high-temperature side outlet of the secondary surface type saturated steam heater (13) is connected with the inlet of the steam generator (12), and the low-temperature side outlet of the secondary surface type saturated steam heater (13) is connected with an external heat supply pipeline.

2. A reheat steam combined mid-discharge steam heating feedwater heating system as claimed in claim 1, wherein: the deaerator (6) is connected with the inlet of a water supply preposed pump (9) in an outlet mode, the water supply preposed pump (9) is connected with the inlet of a steam water supply pump (10) in an outlet mode, and the steam water supply pump (10) is connected with the inlet of one side of the high-pressure heater (5).

3. A reheat steam combined mid-discharge steam heated feedwater heating system as claimed in claim 2 wherein: and the low-temperature side inlet of the primary surface type feedwater heater (11) is connected with the outlet of the feedwater pre-pump (9).

4. A reheat steam combined middle exhaust steam heating water supply and heat supply system as claimed in any one of claims 1 to 3, wherein: the primary surface type feed water heater (11) heats part of feed water at the outlet of the deaerator (6) by using the middle exhaust steam at the outlet of the steam turbine intermediate pressure cylinder (3); and the medium-discharge steam is introduced to the deaerator (6) after being cooled.

5. A reheat steam combined mid-discharge steam heated feedwater heating system as claimed in claim 4 wherein: the steam generator (12) performs mixed secondary heating on the feedwater at the outlet of the primary surface type feedwater heater (11) by using the reheated steam after heat exchange by the secondary surface type steam heater (13), and evaporates the reheated steam into saturated steam.

6. A reheat steam combined mid-discharge steam heated water heating system as claimed in claim 5, wherein: the two-stage surface type steam heater (13) heats saturated steam at the outlet of the steam generator (12) for three times by using reheated steam at the outlet of the high-pressure steam cylinder (2) of the steam turbine and/or at the inlet of the intermediate-pressure steam cylinder (3); the superheated steam heated by the secondary surface type steam heater (13) supplies heat to the outside.

7. A reheating steam combined middle-exhaust steam heating feedwater heating method is characterized in that: the reheating steam combined middle discharge steam heating water supply and heat supply system adopting any one of claims 1-6, comprising the following steps:

step 1: the low-pressure water supply is subjected to primary surface heating by middle-exhaust steam;

the low-pressure feed water is led out from the outlet of the deaerator (6), the low-pressure feed water is firstly subjected to primary surface heating by a primary surface feed water heater (11), and a heating heat source is middle exhaust steam at the outlet of a steam turbine intermediate pressure cylinder (3);

step 2: the low-pressure feed water is secondarily mixed and heated by the reheat steam;

the low-pressure feed water heated in the step 1 enters a steam generator (12), and a heating heat source of the steam generator (12) is reheated steam subjected to heat exchange by a two-stage surface saturated steam heater (13); in a steam generator (12), the low-pressure feed water heated in the step (1) is mixed and heated by the reheated steam and is evaporated into saturated steam;

and step 3: saturated steam is heated by reheat steam in a three-time surface mode;

the saturated steam generated in the step 2 enters a secondary surface type saturated steam heater (13) and is heated until superheated steam supplies heat to the outside; the heating heat source of the two-stage surface saturated steam heater (13) is reheated steam at the outlet of the high-pressure cylinder (2) of the steam turbine and/or at the inlet of the medium-pressure cylinder (3) of the steam turbine.

Technical Field

The invention belongs to the technical field of energy, and particularly relates to a novel energy-saving steam combined water and heat supply system and method.

Background

In order to improve the economy of the units and respond to the national call for energy conservation and emission reduction, at present, most of domestic thermal power generating units are technically improved and externally subjected to steam extraction and heat supply.

The thermal power generating unit carries out steam extraction and heat supply transformation, and the improvement range of the economical efficiency is related to a plurality of 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.

At present, a plurality of steam extraction sources are selected in a conventional heat supply mode, and a direct water spraying throttling mode is adopted to reduce temperature and pressure according to parameter requirements so as to supply heat to the outside. The heating mode has the following defects: the unit has large steam discharge, large cold end loss, low unit efficiency and unreasonable energy level gradient utilization; the heat supply parameters of water spraying heat exchange are unstable and have large fluctuation.

Disclosure of Invention

The invention aims to provide a steam extraction and heat supply system which is reasonable in structure, reliable in system, good in load adaptability, small in heat supply parameter fluctuation and high in host safety.

In order to solve the technical problem, the technical scheme of the invention is to provide a reheating steam combined middle-discharge steam heating water supply and heat supply system, which is characterized in that: the system comprises a straight condensing steam turbine thermal power generator unit and a combined type heat supply system;

the pure condensation steam turbine thermal power generator unit comprises a boiler, a boiler steam outlet is connected with a steam turbine high-pressure cylinder inlet, a steam turbine high-pressure cylinder outlet is connected with a boiler reheat steam inlet, a boiler reheat steam outlet is connected with a steam turbine intermediate pressure cylinder inlet, a steam turbine intermediate pressure cylinder outlet is connected with a steam turbine low-pressure cylinder inlet, a steam turbine low-pressure cylinder outlet is connected with a steam condenser inlet, a steam condenser outlet is connected with one side inlet of a low-pressure heater, the side outlet of the low-pressure heater is connected with a deaerator inlet, the deaerator outlet is connected with one side inlet of the high-pressure heater;

the combined heat supply system comprises a primary surface type feed water heater, wherein a low-temperature side inlet of the primary surface type feed water heater is connected with an outlet of the deaerator, a low-temperature side outlet of the primary surface type feed water heater is connected with an inlet of the steam generator, a high-temperature side inlet of the primary surface type feed water heater is connected with an outlet of the steam turbine medium pressure cylinder, and a high-temperature side outlet of the primary surface type feed water heater is connected with an inlet of the deaerator; the outlet of the steam generator is connected with the low-temperature side inlet of the secondary surface type saturated steam heater, the high-temperature side inlet of the secondary surface type saturated steam heater is connected with the outlet of the high-pressure cylinder of the steam turbine and/or the inlet of the medium-pressure cylinder of the steam turbine, the high-temperature side outlet of the secondary surface type saturated steam heater is connected with the inlet of the steam generator, and the low-temperature side outlet of the secondary surface type saturated steam heater is connected with an external heat supply pipeline.

Preferably, the outlet of the deaerator is connected with the inlet of a water supply preposed pump, the outlet of the water supply preposed pump is connected with the inlet of a steam-driven water supply pump, and the outlet of the steam-driven water supply pump is connected with the inlet of one side of the high-pressure heater.

More preferably, the low-temperature side inlet of the one-stage surface type feedwater heater is connected with the outlet of the feedwater preposition pump.

Preferably, the primary surface type feedwater heater is used for heating part of feedwater at the outlet of the deaerator by using middle exhaust steam at the outlet of the steam turbine intermediate pressure cylinder; and the medium-discharge steam is introduced to the deaerator after being cooled.

More preferably, the steam generator performs a secondary mixed heating of the feedwater at the outlet of the primary surface-type feedwater heater by using the reheated steam after heat exchange by the secondary surface-type steam heater, and evaporates the reheated steam into saturated steam.

Further, the secondary surface type steam heater heats saturated steam at the outlet of the steam generator for three times by using reheated steam at the outlet of the high-pressure cylinder of the steam turbine and/or the inlet of the intermediate pressure cylinder; the superheated steam heated by the secondary surface type steam heater supplies heat to the outside.

The invention also provides a method for heating water and supplying heat by exhaust steam in the reheat steam combination, which is characterized in that: the reheating steam combined middle-exhaust steam heating water supply and heat supply system comprises the following steps:

step 1: the low-pressure water supply is subjected to primary surface heating by middle-exhaust steam;

the low-pressure feed water is led out from the outlet of the deaerator, the low-pressure feed water is firstly subjected to primary surface heating by a primary surface feed water heater, and the heating heat source is middle exhaust steam at the outlet of a steam turbine intermediate pressure cylinder;

step 2: the low-pressure feed water is secondarily mixed and heated by the reheat steam;

the low-pressure feed water heated in the step 1 enters a steam generator, and the heating heat source of the steam generator is reheated steam subjected to heat exchange by a two-stage surface saturated steam heater; in a steam generator, the low-pressure feed water heated in the step 1 is mixed and heated by the reheated steam and is evaporated into saturated steam;

and step 3: saturated steam is heated by reheat steam in a three-time surface mode;

the saturated steam generated in the step 2 enters a secondary surface type saturated steam heater and is heated until superheated steam supplies heat to the outside; the heating heat source of the two-stage surface saturated steam heater is reheated steam at the outlet of a high-pressure cylinder of the steam turbine and/or at the inlet of a medium-pressure cylinder of the steam turbine.

Compared with the traditional direct steam extraction temperature and pressure reduction heat supply system, the reheating steam combined middle-exhaust steam heating water supply heat supply system provided by the invention has the following beneficial effects:

1. the superheat degree of the middle exhaust steam is utilized, the steam exhaust amount of the unit is smaller, the loss of a cold end is smaller, the unit efficiency is higher, and the energy level gradient utilization is more reasonable;

2. the evaporator is used for replacing direct water spraying heat exchange, so that heat supply parameters are more stable, and fluctuation is small.

3. The structure is reasonable, the system is reliable, the load adaptability is good, and the safety of the host is high.

Drawings

FIG. 1 is a schematic view of a reheat steam combined middle exhaust steam heating feedwater heating system provided in this embodiment;

description of reference numerals:

the system comprises a boiler 1, a turbine 2, a turbine high-pressure cylinder 3, a turbine medium-pressure cylinder 4, a turbine low-pressure cylinder 5, a high-pressure heater 6, a deaerator 7, a low-pressure heater 8, a condenser 9, a feed water pre-pump 10, a steam-driven feed water pump 11, a primary surface type feed water heater 12, a steam generator 13 and a secondary surface type saturated steam heater.

Detailed Description

The invention will be further illustrated with reference to the following specific examples.

Fig. 1 is a schematic view of a reheat steam combined medium-exhaust steam heating feedwater heating system provided in this embodiment, the reheat steam combined medium-exhaust steam heating feedwater heating system includes a boiler 1, a steam turbine high-pressure cylinder 2, a steam turbine medium-pressure cylinder 3, a steam turbine low-pressure cylinder 4, a high-pressure heater 5, a deaerator 6, a low-pressure heater 7, a condenser 8, a feedwater pre-pump 9, a steam-driven feedwater pump 10, a primary surface type feedwater heater 11, a steam generator 12, a secondary surface type saturated steam heater 13, and the like.

Wherein, the boiler 1, the turbine high pressure cylinder 2, the turbine intermediate pressure cylinder 3, the turbine low pressure cylinder 4, the high pressure heater 5, the deaerator 6, the low pressure heater 7, the condenser 8, the feed water pre-pump 9 and the steam-driven feed water pump 10 jointly form a conventional pure condensing turbine thermal power generator unit.

The primary surface type water supply heater 11, the steam generator 12 and the secondary surface type saturated steam heater 13 jointly form a combined type heating system. The combined heat supply system utilizes the middle exhaust steam and the reheated steam of the pure condensation steam turbine thermal power generator unit to heat the low-pressure feed water to the superheated steam, and supplies heat to the outside.

The concrete structure is as follows:

pure steam turbine thermal power generating unit includes boiler 1, 2 imports of 1 steam exit linkage steam turbine high pressure jar of boiler, 1 reheat steam import of 2 exit linkage boiler of steam turbine high pressure jar, 3 imports of 1 reheat steam exit linkage steam turbine intermediate pressure jar of boiler, 3 exit linkage steam turbine low pressure jar 4 imports of steam turbine intermediate pressure jar, 4 exit linkage condensers 8 imports of steam turbine low pressure jar, 7 one side imports of 8 exit linkage low pressure feed water heater of condenser, 7 this side exit linkage deaerators 6 imports of low pressure feed water heater, 6 exit linkage feedwater front mounted pump 9 imports of deaerators, 9 exit linkage steam feed water pump 10 imports of feedwater front mounted pump, 5 one side imports of 5 exit linkage high pressure feed water heater of 10 exit linkage high pressure feed water pump, 5 this side exit linkage boiler 1 steam import of high pressure feed.

The combined type heating system comprises a primary surface type water supply heater 11, wherein a low-temperature side inlet of the primary surface type water supply heater 11 is connected with an outlet of a water supply pre-pump 9, a low-temperature side outlet of the primary surface type water supply heater 11 is connected with an inlet of a steam generator 12, a high-temperature side inlet of the primary surface type water supply heater 11 is connected with an outlet of a steam turbine intermediate pressure cylinder 3, and a high-temperature side outlet of the primary surface type water supply heater 11 is connected with an inlet of a deaerator 6. The outlet of the steam generator 12 is connected with the inlet of the low-temperature side of the secondary surface type saturated steam heater 13, the inlet of the high-temperature side of the secondary surface type saturated steam heater 13 is connected with the outlet of the high-pressure cylinder 2 of the steam turbine and/or the inlet of the medium-pressure cylinder 3 of the steam turbine, the outlet of the high-temperature side of the secondary surface type saturated steam heater 13 is connected with the inlet of the steam generator 12, and the outlet of the low-temperature side of the secondary surface type saturated steam heater.

In this embodiment, the heated working medium of the primary surface type water supply heater 11 is taken from the low-pressure water supply at the outlet of the deaerator 6, and is introduced to the steam generator 12 after being heated, and the heated working medium is taken from the medium exhaust steam at the outlet of the steam turbine intermediate pressure cylinder 3, and is introduced to the deaerator 6 after heat exchange.

The heated working medium of the two-stage surface saturated steam heater 13 comes from saturated steam at the outlet of the steam generator 12, the saturated steam is heated to overheat to supply heat to the outside, the heating working medium is taken from reheated steam at the outlet of the high-pressure cylinder 2 of the steam turbine or at the inlet of the medium-pressure cylinder 3 of the steam turbine, and the reheated steam is introduced to the steam generator 12 after heat exchange.

The working medium to be heated of the steam generator 12 is low-pressure feed water from the outlet of the primary surface type feed water heater 11, the heating working medium is reheated steam from the outlet of the secondary surface type saturated steam heater 13, and the low-pressure feed water is mixed with the reheated steam in the steam generator 12 and heated into saturated steam and then led to the secondary surface type saturated steam heater 13.

The operation process of the reheat steam combined middle-exhaust steam heating feedwater heating system provided by the embodiment is as follows:

the heated medium in the working process is low-pressure feed water, and the heating medium is medium-discharge steam and reheat steam. The working process is mainly divided into three flows.

In the first process, low-pressure feed water is subjected to primary surface heating by medium-discharge steam. The low-pressure feed water of the system is led out from a main pipe at the outlet of a feed water pre-pump 9, and the low-pressure feed water is firstly subjected to primary surface heating by a primary surface type feed water heater 11. The heating heat source is middle exhaust steam at the outlet of the steam turbine middle pressure cylinder 3.

In the second flow, the low-pressure feed water is secondarily mixed and heated by the reheat steam. The low-pressure feed water heated in the first process enters the steam generator 12, and the heat source in the process is reheated steam subjected to heat exchange in the third process. In the steam generator 12, low-pressure feed water is mixed and heated by reheat steam, and evaporated into saturated steam.

In the third process, the saturated steam is heated by the reheat steam three times in a surface mode. Saturated steam generated in the second flow enters the secondary surface type saturated steam heater 13 and is heated until superheated steam supplies heat to the outside. The heating heat source is reheat steam at the outlet of the high-pressure turbine cylinder 2 or the inlet of the intermediate-pressure turbine cylinder 3.

The reheating steam combined middle-discharge steam heating water supply and heat supply system provided by the invention firstly utilizes the superheat degree of middle-discharge steam to heat water and then enters the steam generator, the evaporation heat source of the steam generator adopts reheating steam, the superheat degree of the reheating steam is firstly used for overheating and heat absorption of saturated steam at the outlet of the steam generator and then enters the evaporator, and latent heat required by conversion of saturated water to saturated steam is provided. Compared with a direct temperature and pressure reduction heat supply system for extracting steam, the system utilizes the superheat degree of the middle exhaust steam, the steam exhaust amount of the unit is smaller, the cold end loss is smaller, the unit efficiency is higher, and the energy level gradient utilization is more reasonable.

Compared with a direct temperature and pressure reducing heat supply system for steam extraction, the system utilizes the evaporator to replace direct water spraying heat exchange, and has more stable heat supply parameters and small fluctuation. Taking a 600MW steam turbine generator unit for supplying heat to the outside at 400t/h as an example, after the system is applied, the coal consumption of the unit for generating electricity is reduced by 4.5g/kWh, the annual electricity generation amount is 330000 thousands of kWh, the annual coal saving amount is 14850t, the unit price of standard coal is 800 yuan/t, and the annual hair income is increased by 1188 ten thousand yuan.

While the invention has been described with respect to a preferred embodiment, it will be understood by those skilled in the art that the foregoing and other changes, omissions and deviations in the form and detail thereof may be made without departing from the scope of this invention. Those skilled in the art can make various changes, modifications and equivalent arrangements, which are equivalent to the embodiments of the present invention, without departing from the spirit and scope of the present invention, and which may be made by utilizing the techniques disclosed above; meanwhile, any changes, modifications and variations of the above-described embodiments, which are equivalent to those of the technical spirit of the present invention, are within the scope of the technical solution of the present invention.