Background technique
Exhaust steam of electric power plant (i.e. turbine low pressure cylinder steam discharge) contains the very big latent heat of vaporization.Into the main steam of steam turbine,
Enthalpy is generally 3500kj/kg, its enthalpy of turbine low pressure cylinder steam discharge is generally 2400-2600kj/kg or so.
Exhaust steam of electric power plant is typically all to arrange Xiang great Qi, heat by cooling equipment (Air-Cooling Island, condenser, air cooling tower etc.) at this stage
Amount is wasted in vain, but also wants water consumption power consumption.The energy that power plant is lost by steam exhaust is exactly cold end loss.Power plant's hair
Electrical efficiency about 40%, loss about 60%, wherein cold end loss accounts for more than 50%.Therefore, exhaust steam of electric power plant waste heat is recycled, cold end is reduced
Loss is most potential one piece in power plant for energy conservation field.Recycle its exhaust steam residual heat to improve China's efficiency of energy utilization, subtract
Few environmental pollution is of great significance.
It recycles exhaust steam of electric power plant waste heat and reduces the technology and systems of cold end loss, since its energy-saving effect is significant, increasingly
Paid attention to.Steam power plant's exhaust steam residual heat is recycled, heat supply, the technological means for being exactly widely popularized and applying are used for.More than steam exhaust
In recuperation of heat heating system, generally step (multistage) heating system carries out Multi-stage heating to heat supply network return water.
Upgrading is carried out to low-grade steam exhaust using steam jet ejector technology and is used for heat supply, is that high efficiente callback utilizes more than steam exhaust
The effective means of heat.Steam jet ejector technology has the advantages that equipment is simple, reliable for operation, cost is relatively low.But it is constrained to steam
The performance of vapour injector, for running the lower unit of back pressure, the temperature for promoting hot net water using single-stage vapor injector is limited,
User's supply water temperature requirement can not directly be met.
This results in some problems: single-stage exhaust steam residual heat recycles heat supply, and steam exhaust yield is limited, more than entire steam power plant's steam exhaust
Hot energy-saving potential is not excavated all;Single-stage exhaust steam residual heat recycles heat supply, is not suitable for unit change working and is brought
Economy;Single-stage exhaust steam residual heat recycles heat supply, just in case breaking down, dead steam recovery system stops working.Steam exhaust cannot be by
Recycling, this not only influences energy-saving effect, but will influence to supply thermally safe.Just in case failure occurred in deep cooling season, it may appear that heating load is not
Foot, the temperature of resident's family do not reach requirement, and heat supply accident occur.
Summary of the invention
The purpose of the present invention is to provide a kind of two-stage series exhaust steam residual heats to recycle heating system, is being returned with meeting power plant
It receives in steam power plant's exhaust steam residual heat heating energy-saving transformation process, further increases for thermal safety, improves energy-saving effect.
To achieve the goals above, the technical scheme is that
A kind of two-stage series exhaust steam residual heat recycling heating system, including steam turbine, level-one steam jet ejector, second steam
Injector, heat supply network heat exchanger, condenser;It is characterized in that, the steam exhaust pipeline between last stage vane of steam turbine outlet and condenser
Upper setting pass-out steam pipeline, extension steam exhaust are connected to the injection entrance of level-one steam jet ejector;Heat supply among steam turbine
Steam extraction outlet is connect with level-one steam jet ejector Working-fluid intaking;The steam drain and second steam of level-one steam jet ejector spray
The injection entrance of device is connected;Heat supply steam extraction outlet is also connect with second steam injector Working-fluid intaking among steam turbine;Two
The steam drain of grade steam jet ejector is connected with heat exchangers for district heating shell-side;Primary net water return pipeline is added by heat exchangers for district heating
Heat.
System proposed by the present invention can effectively promote hot net water temperature rise, and then promote heating system overall efficiency.
(1) steam jet ejector device structure is simple, low in cost, reliable for operation;
(2) by two-stage steam jet ejector series connection recycling exhausted spare heat, system can be made to be suitable for low back pressure operating condition, and do not had to
Increase other equipment;
(3) by setting bypass, two-stage steam jet ejector can be made to be switched to single-stage, is suitable for the operating conditions such as high back pressure.
Specific embodiment
1,2 the invention will be further described with reference to the accompanying drawing, it should be understood that content described herein is only used for
The bright and explanation present invention, is not intended to limit the present invention.
Steam jet ejector be a kind of structure it is simple, without mechanical moving element, safe and reliable energy saver, be widely used in
Multiple fields.Fig. 1 gives the schematic illustration of steam jet ejector, introduces high steam as power from Working-fluid intaking and steams
Vapour forms high speed steam flow by nozzle expansion, and pressure reduction forms low-pressure area, passes through injection entrance draws low pressure steam to mixing
Chamber, reduction of speed, which boosts, after mixing to form middle pressure steam of the pressure between high steam and low-pressure steam and is discharged through steam drain,
Essence is the pressure that low-pressure steam is promoted using the kinetic energy of high steam.
As shown in Fig. 2, a kind of two-stage steam jet ejector recycling exhaust steam residual heat heating system is by steam turbine 1, generator 2, one
Grade steam jet ejector 3, second steam injector 4, valve 5, valve 6, valve 7, valve 8, heat supply network heat exchanger 9, peak load calorifier
10, the equipment such as condenser 11 and water circulating pump 12 form;
Pass-out steam pipeline is set on steam exhaust pipeline between the outlet of 1 exhaust stage blade of steam turbine and condenser 11, for drawing
Part steam exhaust is connected to the injection entrance of level-one steam jet ejector 3 out;1 intermediate heat supply steam extraction outlet of steam turbine and level-one steam spray
The connection of 3 Working-fluid intaking of emitter;The steam drain of level-one steam jet ejector 3 is connected with the injection entrance of second steam injector 4;
The intermediate heat supply steam extraction of steam turbine 1 outlet is also connect with 4 Working-fluid intaking of second steam injector;Second steam injector 4
Steam drain is connected with 9 shell-side of heat exchangers for district heating;1 intermediate heat supply steam extraction outlet of steam turbine is connected with 10 shell-side of peak load calorifier;
Steam exhaust control valve 5 is installed on the steam exhaust injection pipeline of level-one steam jet ejector 3, level-one steam jet ejector 3 enters
Power steam control valve 6 is installed, 3 steam drain of level-one steam jet ejector installs steam discharge control valve 7 before mouthful.In addition, in steam exhaust
Setting switching bypasses and is connected to the injection entrance of second steam injector 4 on injection pipeline, installs and cuts in switching bypass
Change control valve 8;
Step (multistage) heating system is constituted by heat exchangers for district heating 9 and peak load calorifier 10, heat supply network return water is carried out multistage
Heating.Heat exchangers for district heating 9 is connected with peak load calorifier 10, and primary net return water passes sequentially through heat exchangers for district heating 9, peak load calorifier 10
It is heated, and exports primary net and supply water.
The condensate system of the condensed water of heat exchangers for district heating 9 and peak load calorifier 10 access power plant carries out water recycling.Spike
Hydrophobic 9 shell-side of inflow heat exchangers for district heating of heater 10;The condensed water of 9 shell-side outlet of heat supply network heat exchanger with not by the steamer of injection
1 steam exhaust of machine passes through formed condensed water after condenser 11, and two strands of condensed waters enter the condensation return water system of power plant after converging.
Under normal conditions, fired power generating unit back pressure is lower, causes the taste of steam exhaust lower, can not directly utilize.Steam injection
Device exhaust steam residual heat upgrading heat supply process utilizes the steamer of steam turbine heat supply steam extraction injection low pressure by introducing steam jet ejector equipment
Machine steam exhaust enters back into heat supply network heat exchanger and heats to primary net return water after forming mixed vapour, to realize to more than steam exhaust
The effective use of heat.
For the unit back pressuce of 5~15kPa or so, primary net return water directly can not be heated with exhaust steam residual heat;While in view of
Heat supply network return water temperature directly can not be heated to heat user needs by the outlet vapor of the heating ability of injector, single-stage injector
Temperature, therefore the heating process for being considered as gradually by water temperature heating to required temperature, entirely once netting is divided into heat exchangers for district heating
It is heated with 2 grades of peak load calorifier, and the heat source of heat exchangers for district heating is to be formed by elevated pressures after two-stage steam jet ejector is connected
Steam.
Specific work process is as follows: exhaust steam in steam turbine waste heat for supplying system is sprayed by steam turbine 1, generator 2, level-one steam
Device 3, second steam injector 4, valve 5, valve 6, valve 7, valve 8, heat supply network heat exchanger 9, peak load calorifier 10, condenser 11
It is formed with equipment such as water circulating pumps 12.1 exhaust stage blade of steam turbine outlet condenser 11 between setting steam exhaust injection pipeline with
The injection entrance of level-one steam jet ejector 3 is connected to;The working fluid of steam turbine 1 intermediate extraction outlet and level-one steam jet ejector 3
Entrance connection.The work of injector is utilized after heat supply steam extraction passes through 3 acceleration and pressure decrease of level-one steam jet ejector as working steam
Steam turbine low-temp low-pressure steam exhaust is drawn into the mixing chamber of injector by characteristic, and two strands of steam are quickly completing heat and mass exchange
Afterwards, uniform mixed vapour is formed.Mixed vapour is sent to second level steaming after diffuser deceleration is compressed to certain back pressure
The injection entrance of vapour injector 4.Meanwhile working fluid of another burst of heat supply steam extraction as second injector 4, it is used for injection first
Stock mixed vapour.Second steam injector 4 exports mixed vapour and is sent to heat supply network heat exchanger 9 for heating heat supply network primary water.
Primary net return water passes sequentially through heat exchangers for district heating 9, peak load calorifier 10 carries out second level heating;And the hydrophobic stream of peak load calorifier 10
Enter 9 shell-side of heat exchangers for district heating.Condensed water is not formed by condenser by the exhaust steam in steam turbine of injection, and is exported with heat exchangers for district heating
Condensed water converge after enter power plant condensation return water system.
In order to realize system above in the wide load of unit, wide range of environmental conditions Nei Zhuo efficient operation, the injection of level-one steam
Steam exhaust control valve 5 is installed, installation power steam is adjusted before 3 entrance of level-one steam jet ejector on the steam exhaust injection pipeline of device 3
Valve 6,3 steam drain of level-one steam jet ejector install steam discharge control valve 7,3 operating condition of level-one steam jet ejector can be adjusted.
In addition, setting switching bypasses and is connected to the injection entrance of second steam injector 4 on steam exhaust injection pipeline, by the switching
Road installation switches control valve 8, installs power steam control valve 13 before the entrance of second steam injector 4.
In the low back pressure operating condition of unit, two-stage steam jet ejector is run simultaneously, is adjusted level-one steam using valve 5,6,7 and is sprayed
3 operating condition of emitter adjusts 4 operating condition of second steam injector using valve 8, valve 13, realizes the tandem working of two-stage steam jet ejector,
Exhaust steam in steam turbine is aspirated simultaneously and carries out upgrading pressurization, is aspirated maximum using steam amount.In the unit when back pressure operating condition, two-stage is steamed
Vapour injector is run simultaneously, adjusts 3 operating condition of level-one steam jet ejector using valve 5,6,7, valve 8 closes cutting suction steam turbine
Steam exhaust is realized and carries out double stage tandem upgrading pressurization after exhaust steam in steam turbine is aspirated in the tandem working of two-stage steam jet ejector, single-stage, taken out
It inhales medium using steam amount.In unit high back pressure operating condition, valve 5,6,7 is closed, level-one steam jet ejector 3 is closed and works, valve
Door 8 opens suction exhaust steam in steam turbine, adjusts 4 operating condition of second steam injector using valve 8, valve 13, single-stage aspirates steam turbine
Upgrading pressurization is carried out after steam exhaust, is aspirated minimum using steam amount.
Two-stage steam jet ejector is mutually spare, realizes work switching, can be improved for thermally safe, avoid heat supply accident.When one
When grade 3 failure of steam jet ejector, valve 5,6,7 is closed, level-one steam jet ejector 3 is closed and works, utilize second steam injector 4
It works independently, ensures heat supply running.When second steam 4 failure of injector, valve 8 and valve 13, second steam injection are closed
Device 4 does not work, and injection entrance accesses 3 steam discharge of level-one steam jet ejector, only uses as steam passage, is sprayed using level-one steam
Emitter 3 works independently, and ensures heat supply running.
In addition, different intermediate extraction outlets can be used in two-stage steam jet ejector steam turbine, and peak load calorifier can also be adopted
It is exported with different intermediate extractions.
Finally, it should be noted that being not intended to restrict the invention the foregoing is merely explanation of the invention, although to this hair
It is bright to be described in detail, it for those skilled in the art, still can be to aforementioned documented technical solution
It modifies or equivalent replacement of some of the technical features.All within the spirits and principles of the present invention, made
Any modification, equivalent substitution, improvement and etc. should all be included in the protection scope of the present invention.