CN115387979A

CN115387979A - System for generating medium-pressure steam by combining steam-driven steam compressor and steam ejector

Info

Publication number: CN115387979A
Application number: CN202210467621.5A
Authority: CN
Inventors: 石浩林; 张若愚; 白博峰
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2022-04-29
Filing date: 2022-04-29
Publication date: 2022-11-25

Abstract

The invention discloses a system for generating medium-pressure steam by combining a steam-driven steam compressor and a steam ejector, wherein high-pressure steam led out by steam extraction or steam exhaust of a high/medium pressure cylinder of a steam turbine enters a driving steam turbine through a high-pressure steam source pipeline to do work, and the coaxial steam compressor is driven to carry out primary pressurization on low-pressure extracted steam or exhaust steam of the steam turbine; the exhaust steam after the work of the steam turbine is driven is conveyed to a nozzle of the steam ejector, and the exhaust steam after pressure reduction and speed increase is injected, so that the secondary pressurization of the low-pressure steam is realized, and finally the steam meeting the requirement of industrial thermal parameters is output. The invention utilizes the pressure energy of partial high-pressure extraction steam of the steam turbine generator unit of the power plant in a cascade manner, recovers the low-pressure extraction steam or the exhaust steam of the steam turbine to generate the steam which can meet the requirement of industrial hot steam, has small influence on the generating capacity and the frequency modulation capacity of the unit, can effectively relieve the problem of limitation of industrial hot steam sources, greatly reduces the consumption of the high-pressure steam, efficiently recovers the low-pressure steam or the exhaust steam, and reduces the steam consumption cost of users.

Description

System for generating medium-pressure steam by combining steam-driven steam compressor and steam ejector

Technical Field

The invention relates to the technical field of industrial steam extraction and supply of large and medium steam turbine generator units, in particular to a system for generating medium-pressure steam by combining a steam-driven steam compressor and a steam ejector.

Background

With the continuous development of socioeconomic of China, the industrial heat demand is more vigorous, and the domestic industrial heat demand accounts for about 70% of the total demand.

Environmental protection problems are more and more emphasized in China, and a large number of small heat supply boilers with high energy consumption and large pollution are forcibly dismantled, so that a plurality of industrial heat sources are limited. The industrial steam supply parameters are not completely matched with the originally designed industrial steam extraction parameters of the heat supply unit of the power plant, and in order to meet the requirements of the industrial steam supply parameters, the economy of the power plant is influenced no matter the temperature and the pressure of high-parameter steam are simply reduced or the opening degree of a heat supply regulating valve is regulated to ensure the industrial steam supply parameters, so that the adjustable range of the generating capacity of the unit is narrowed, and the primary frequency modulation capacity is reduced.

There are two conventional industrial heating schemes: selecting a certain steam source to match with a temperature and pressure reduction device to obtain steam with required parameters; and (II) taking high-parameter steam as a power steam source, pumping low-pressure steam through a pressure matcher, and mixing to obtain steam with required parameters from an outlet. However, both of these two schemes consume a large amount of high-temperature high-pressure steam, and the heat energy loss in the production process is large, which leads to the increase of the cost of steam for users.

Disclosure of Invention

The invention aims to provide a system for generating medium-pressure steam by combining a steam-driven steam compressor and a steam ejector, which utilizes the pressure energy of partial high-pressure extraction steam of a steam turbine generator unit of a power plant to recover low-pressure extraction steam or exhaust steam of a steam turbine and generate steam capable of meeting industrial heat.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a system for generating intermediate pressure steam by combining a steam driven steam compressor and a steam ejector includes a drive turbine, a screw steam compressor, and a steam ejector.

The inlet and outlet of the driving turbine are respectively provided with a high-pressure steam source pipeline and an injection driving steam pipeline; the high-pressure steam source pipeline is connected with a steam extraction or exhaust pipeline of a high/medium pressure cylinder of a steam turbine generator unit of a power plant, a check valve and an electric isolation valve are installed, and an injection driving steam pipeline is connected with a steam injector.

The inlet and outlet of the steam compressor are respectively provided with a low-pressure steam source pipeline and an injection confluence pipeline; the low-pressure steam source pipeline is connected with a low-pressure steam extraction or exhaust steam pipeline of a steam turbine generator unit of a power plant, a check valve and an electric isolation valve are installed, and the injection confluence pipeline is connected with a steam ejector.

The outlet of the steam ejector is provided with an automatically controlled electric regulating valve.

High-pressure steam led out by the steam extraction or the steam exhaust of the high/medium pressure cylinder firstly enters a driving steam turbine to do work, and drives a coaxial steam compressor to rotate so as to carry out primary pressurization on the low-pressure steam; the exhausted steam after the work of the steam turbine is driven enters a nozzle of a steam ejector as working steam, and the exhausted steam after being pressurized by a steam compressor is ejected after pressure reduction and acceleration, so that the secondary pressurization of the low-pressure extracted steam or the exhausted steam of the steam turbine is realized, and finally, mixed steam meeting the requirement of industrial thermal parameters is output.

Compared with the prior art, the invention has the beneficial effects that:

compared with a single steam ejector, the system for generating the medium-pressure steam by combining the steam-driven steam compressor and the steam ejector provided by the invention adopts two-stage pressurization, reduces the compression ratio and the expansion ratio of the steam ejector, increases the injection coefficient of the steam ejector and the kinetic energy transfer efficiency in the mixing process, and thus reduces the consumption of high-pressure extracted steam. The invention can utilize the pressure energy of partial high-pressure extraction steam of the steam turbine generator unit of the power plant, can generate steam which can meet industrial heat while recovering low-pressure extraction steam or exhaust steam of the steam turbine, and can not influence the generating and frequency modulation capability of the unit.

Drawings

FIG. 1 is a process flow diagram of the present invention

Detailed Description

The present invention will now be described in further detail with reference to the attached drawings, which are illustrative, but not limiting, of the present invention.

Referring to the drawings, only a system for generating medium pressure steam by combining medium pressure steam exhaust and low pressure steam exhaust is shown. If other high-pressure steam sources and low-pressure steam sources are adopted, the positions of the corresponding steam extraction ports are only required to be changed.

The invention includes a drive turbine, a screw steam compressor, and a steam ejector. The inlet and outlet of the driving turbine are respectively provided with a high-pressure steam source pipeline and an injection driving steam pipeline; the high-pressure steam source pipeline is connected with a steam extraction or exhaust pipeline of a high/medium pressure cylinder of a steam turbine generator unit of a power plant, a check valve and an electric isolation valve are installed, and an injection driving steam pipeline is connected with a steam injector. The inlet and outlet of the steam compressor are respectively provided with a low-pressure steam source pipeline and an injection confluence pipeline; the low-pressure steam source pipeline is connected with a low-pressure steam extraction or exhaust steam pipeline of a steam turbine generator unit of a power plant, a check valve and an electric isolation valve are installed, and the injection confluence pipeline is connected with a steam ejector.

A system for combined generation of medium pressure steam from a steam driven steam compressor and steam ejector includes a drive turbine 1, a screw steam compressor 2 and a steam ejector 3. The inlet and outlet of the driving steam turbine 1 are respectively provided with a high-pressure steam source pipeline 4 and an injection driving steam pipeline 5; the high-pressure steam source pipeline 4 is connected with a steam extraction or exhaust pipeline of a high/medium pressure cylinder of a steam turbine generator unit of a power plant, a check valve 8 and an electric isolation valve 9 are installed, and the injection driving steam pipeline 5 is connected with the steam injector 3. The inlet and outlet of the steam compressor 2 are respectively provided with a low-pressure steam source pipeline 6 and an injection confluence pipeline 7; the low-pressure steam source pipeline 6 is connected with a low-pressure steam extraction or exhaust steam pipeline of a steam turbine generator unit of a power plant, a check valve 10 and an electric isolation valve 11 are installed, and the injection confluence pipeline 7 is connected with the steam injector 3. The outlet of the steam ejector 3 is provided with an automatically controlled electric regulating valve 12.

A method for recovering low-pressure extracted steam or dead steam of a steam turbine by using the system to generate hot steam capable of meeting industrial requirements comprises the following steps:

high-pressure extracted steam led out by a high/medium pressure cylinder of the steam turbine enters a driving steam turbine 1 through a high-pressure steam source pipeline 4 to do work, a coaxial steam compressor 2 is driven to rotate, and low-pressure extracted steam or exhaust steam of the steam turbine is subjected to primary pressurization; the exhaust steam after driving the steam turbine 1 to do work is taken as working steam and is conveyed to a nozzle of a steam ejector 3 through an injection driving steam pipeline 5, the exhaust steam after being pressurized by a steam compressor is ejected after pressure reduction and speed increase, so that the secondary pressurization of low-pressure extraction steam or exhaust steam of the steam turbine is realized, and finally mixed steam meeting the requirement of industrial thermal parameters is output.

Claims

1. A system for generating intermediate pressure steam using a combination of a steam driven steam compressor and a steam ejector, the system comprising: the system comprises a driving steam turbine (1), a steam compressor (2) and a steam ejector (3), wherein the steam compressor and the steam ejector are coaxial with the steam turbine, an inlet of the driving steam turbine (1) is connected with a steam extraction or exhaust pipeline of a high/medium pressure cylinder of the generator set, and an outlet of the driving steam turbine is connected with a high-pressure inlet of the steam ejector (3); the inlet of the steam compressor (2) is connected with a low-pressure steam extraction or exhaust steam pipeline of the generator set, and the outlet is connected with the low-pressure inlet of the steam ejector (3); the high-pressure inlet and the low-pressure inlet of the steam ejector (3) are respectively connected with the driving steam turbine (1) and the steam compressor (2), and the outlet is connected with a steam supply pipeline of a power plant.

2. The system for combined generation of intermediate pressure steam from a steam operated vapor compressor and a steam ejector as set forth in claim 1, wherein: the inlet and the outlet of the driving turbine (1) are respectively provided with a high-pressure steam source pipeline (4) and an injection driving steam pipeline (5); the high-pressure steam source pipeline (4) is connected with a steam extraction or exhaust pipeline of a high/medium pressure cylinder of a steam turbine generator unit of a power plant, a check valve (8) and an electric isolation valve (9) are installed, and the injection driving steam pipeline (5) is connected with the steam injector (3).

3. The system for combined generation of intermediate pressure steam from a steam operated vapor compressor and a steam ejector as set forth in claim 1, wherein: the steam compressor (2) adopts a screw type steam compressor, and the inlet and the outlet are respectively provided with a low-pressure steam source pipeline (6) and an injection confluence pipeline (7); the low-pressure steam source pipeline (6) is connected with a low-pressure steam extraction or exhaust steam pipeline of a steam turbine generator unit of a power plant, a check valve (10) and an electric isolation valve (11) are installed, and the injection converging pipeline (7) is connected with the steam ejector (3).

4. The system for combined generation of intermediate pressure steam from a steam operated vapor compressor and a steam ejector as set forth in claim 1, wherein: an automatically controlled electric regulating valve (12) is arranged at the outlet of the steam ejector (3).