CN215979528U - Steam condensing type isolated thermal state starting system without auxiliary steam for external heat supply unit - Google Patents

Abstract

The utility model relates to the technical field of single-machine thermal-state starting of power plants, and discloses an isolated thermal-state starting system without auxiliary steam for a steam condensing type external heat supply unit, which comprises a first steam condensing type unit and a second steam condensing type unit, wherein the first steam condensing type unit and the second steam condensing type unit are respectively connected with a heat supply branch cylinder through a first pipeline and a second pipeline to provide a steam source for the heat supply branch cylinder; after the tripping of the unit can be guaranteed through the system, steam for starting the unit is stably provided, the pressure of a steam source is stable, the steam quantity is sufficient, and the requirement that the unit is started from safety to grid-connected power generation can be met.

Description

Steam condensing type isolated thermal state starting system without auxiliary steam for external heat supply unit

Technical Field

The utility model relates to the technical field of single-machine thermal-state starting of power plants, in particular to an isolated thermal-state starting system without auxiliary steam for a condensing type external heat supply unit.

Background

At present, two 600MW units of a power plant are started by adopting equipment configured by the unit units for starting operation, and since the production in 2008, auxiliary steam used for starting the units mainly comes from a starting boiler, machine-approaching steam and cold re-steam of the unit, the auxiliary steam pressure is 0.8-1.2 MPa (a), and the temperature is 260-360 ℃. After the single machine is operated and tripped, the hot-state starting steam is mainly used for starting a boiler or a unit to adjust cold re-steam pressure by using a high-pressure and low-pressure bypass, and auxiliary steam is supplied by cold re-steam to realize the processes of commissioning a shaft seal of a steam turbine, flushing of a steam pump set, heating of a deaerator and heating of a plasma air heater. But the starting boiler is old and has the problem of difficult ignition. Compared with the method that the unit utilizes a high-pressure bypass and a low-pressure bypass to adjust cold vapor pressure and then supply auxiliary vapor, the unit needs to be decompressed and pressurized after tripping, the auxiliary vapor pressure is provided by intermittently starting the high bypass to meet the vapor utilization parameter requirement because the high bypass rear vapor has no temperature reduction water, and the high bypass rear temperature has to be noticed. To control cold reheat pressure, low side-by-side turndown, the reheater is in a short dry-fire condition during startup.

SUMMERY OF THE UTILITY MODEL

Aiming at the defects of the prior art, the utility model provides a condensing type isolated thermal state starting system without auxiliary steam for an external heat supply unit, which utilizes the residual steam of the unit system to stably provide steam for the thermal state starting of the unit, has stable steam source pressure and sufficient steam quantity, does not need to intermittently open high side to meet the parameter requirements of metal and steam, has relatively low requirements on the technical level and the compactness of operation of unit operation operators, and can meet the requirements of the unit from safe starting to grid-connected power generation.

In order to achieve the purpose, the utility model is realized by the following technical scheme: the utility model provides an external heat supply unit of condensing steam does not have isolated hot starting system of steam assisted, includes condensing steam formula unit and No. two condensing steam formula units, condensing steam formula unit with No. two condensing steam formula units are connected with the heat supply gas-distributing cylinder through first pipeline and second pipeline respectively, and is right the heat supply gas-distributing cylinder provides the vapour source, be connected with the heat supply mother pipe of the same kind on the heat supply gas-distributing cylinder, the heat supply mother pipe carries steam to each heat supply user, be connected with third pipeline and fourth pipeline on the heat supply gas-distributing cylinder, the heat supply gas-distributing cylinder carries steam to unit gas-assisted header through the third pipeline, the heat supply gas-distributing cylinder carries steam to No. two unit gas-assisted headers through the fourth pipeline.

In some embodiments of the present application, a first manual isolation door and a third electric isolation door are disposed on the third duct.

In some embodiments of the present application, the third pipe is provided with a plurality of first hydrophobic points.

In some embodiments of the present application, the number of the first hydrophobic points is three.

In some embodiments of the present application, a second manual isolation door and a fourth electric isolation door are disposed on the fourth duct.

In some embodiments of the present application, a plurality of second hydrophobic points are disposed on the fourth pipe.

In some embodiments of the present application, the number of the second hydrophobic points is four.

In some embodiments of the present application, the first duct and the second duct are provided with a first isolation power door and a second isolation power door, respectively.

This application is through utilizing unit system self complementary steam to stably provide the hot start-up of unit and use vapour, throw the bearing seal from the turbine, the evacuation, the steam pump group dashes to change, the boiler is watered, ignite to the boiler, the intensification is boosted, it dashes to change to go to the turbine again, the electricity generation of being incorporated into the power networks, whole process unit each item parameter accords with the standard completely, it is stable to start steam pressure, the reserve is sufficient, the steam turbine bearing seal has been satisfied, the steam pump group dashes to change, the oxygen-eliminating device heating and the vapour demand of using of plasma air heater heating, the security and the reliability of the isolated start-up of unit have been guaranteed.

Drawings

FIG. 1 is an isolated thermal starting system of a condensing type external heating unit without auxiliary steam according to an embodiment of the utility model;

in the figure, 1, a condensing unit; 2. a second condensing unit; 3. a heat supply steam distributing cylinder; 4. The first unit auxiliary steam header; 5. the second unit auxiliary steam header; 6. a first conduit; 7. a second conduit; 8. a third pipeline; 9. a fourth conduit; 10. a heat supply main pipe; 11. a first electrically powered isolation door; 12. a second electrically powered isolation door; 13. a third electrically powered isolation door; 14. a fourth electrically powered isolation door; 15. a first manual isolation door; 16. a second manual isolation door.

Detailed Description

The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the utility model but are not intended to limit the scope of the utility model.

In the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present application.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.

In the description of the present application, it is to 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 meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

As shown in fig. 1, in some embodiments of the present application, an isolated thermal starting system without auxiliary steam for a condensing unit includes a first condensing unit 1 and a second condensing unit 2, high-temperature reheat steam, low-temperature reheat steam, and four-stage extraction steam of the first condensing unit 1 and the second condensing unit 2 are used as steam sources for a heat supply industry, the first condensing unit 1 supplies heat steam from a first pipeline 6 to a heat supply branch cylinder 3 through a first electric isolation door 11, the second condensing unit 2 supplies heat steam from a second pipeline 7 to the heat supply branch cylinder 3 through a second electric isolation door 12, a heat supply main pipe 10 connected to the heat supply branch cylinder 3 is used for supplying heat to an external user, and the heat supply main pipe 10 supplies steam to each heat supply user.

It should be noted that, the heat supply medium for the heat supply branch cylinder 3 by the two units is superheated steam, the heat supply steam pressure is 1.3-2.0 mpa (a), the temperature is 320-380 ℃, the average heat supply amount of each unit is 150t/h, the heat supply steam of the two units is sent to the heat supply branch cylinder 3 to be mixed, the heat supply main pipe 10 connected with the heat supply branch cylinder outside the plant area is a DN800 steam pipeline, and the length of the heat supply main pipe 10 reaches more than 40 kilometers, so as to ensure that the steam can be conveyed to each heat supply user, and to meet the heat demand of the user.

In some embodiments of the present application, a new pipeline is connected to the auxiliary steam headers of the #1 and #2 units at the standby interface of the external heat supply steam distributing cylinder 3, respectively, and is used as a steam source of the auxiliary steam of the units; the heat supply steam distributing cylinder 3 inputs steam into the first unit auxiliary steam header 4 through a third pipeline 8, and inputs steam into the second unit auxiliary steam header 5 through a fourth pipeline 9; when the unit is tripped after running, the steam of the heat supply steam distributing cylinder 3 is used as a steam source of one path of the auxiliary steam system, the stable auxiliary steam supply for 2 hours under the hot-state starting of the unit can be met, the starting time requirement of the unit is met, the system is simple in structure, safe and reliable, the back-and-forth switching process of the system is stable, the time is short, compared with the traditional operation of controlling the cold pressure and the temperature according to high side, the auxiliary steam pressure fluctuation caused by paying attention to the high side back temperature is avoided, the time is saved in the operation, and the operation difficulty is reduced.

The auxiliary steam system of the power plant unit is provided with a steam source starting boiler, cold re-steam and temporary steam of the power plant unit, the auxiliary steam pressure is 0.8-1.2 MPa and the temperature is 260-360 ℃, and main users have steam for a shaft seal system of the power plant unit, steam for starting a steam pump unit, steam for heating a deaerator, steam for heating a fan heater, steam for steam blowing of a steam pre-heater and steam for steam blowing of denitration steam; the steam and temperature of the heat supply are very close to the parameters of the starting steam, and the steam storage capacity of the pipeline is large, so that the pressurized steam of the heat supply pipeline can stably provide the starting steam of the unit for a long time, the stability of steam supply is ensured, and the steam for the shaft seal and the heating of the deaerator can be synchronously input, so that the metal thermal shock of the unit is reduced; the shaft seal pressure is more stable, the rotating speed of the air pump is easy to control, and the heating effect of the plasma air heater is good; the whole process can be normally adjusted at the low side, so that the phenomenon of dry burning of the reheater is avoided.

In some embodiments of the present application, a first manual isolation door 15 and a third electric isolation door 13 are disposed on the third pipeline 8, a second manual isolation door 16 and a fourth electric isolation door 14 are disposed on the fourth pipeline 9, and the manual isolation door and the electric isolation door are additionally disposed at the auxiliary steam header of the unit, so that the isolation in daily operations is facilitated.

In some embodiments of the present application, a plurality of first hydrophobic points are disposed on the third pipeline 8, a plurality of second hydrophobic points are disposed on the fourth pipeline 9, and condensed water in the pipelines can be removed by disposing the hydrophobic points, so as to ensure normal working conditions of each device and reduce working medium loss in a thermodynamic system.

According to the operation condition of the unit, the number of the hydrophobic points can be reasonably set, three first hydrophobic points are arranged on the third pipeline 8 of the plant, and four second hydrophobic points are arranged on the fourth pipeline 9.

In conclusion, the technical scheme is provided for the hot-state starting of the unit after tripping, key node operation guidance is provided, and specific parameter control and operation are executed according to the hot-state starting operation order of the unit.

1. Equipment inspection and auxiliary steam source switching: after the unit trips, checking that tripping protection actions of mechanical, electric and furnace equipment are normal, and normally switching the service power, otherwise, processing according to total loss of the service power; the method comprises the following steps of closing hot re-steam, cold re-steam, a four-section steam extraction and heat supply electric door and a check valve of a unit in a linkage manner, informing a long-value emergency contact company for a user of interruption of heat supply of the unit, starting a first-level emergency plan, checking that the steam consumption electric door of a heat supply user is closed within a specified time, and maintaining the pressure of a heat supply pipeline; and closing redundant users and drainage of the auxiliary steam header of the tripping unit, separating other steam sources of the auxiliary steam header, inputting heat to auxiliary steam, paying attention to drainage of a heating pipe in the inputting process to prevent pipeline vibration, and controlling the auxiliary steam pressure to be stable at about 0.7MPa by using a throttle of an electric valve for supplying heat to the auxiliary steam.

2. Commissioning a steam turbine shaft seal system and draining inspection: checking the operation condition of a steam turbine shaft seal system, monitoring the pressure of a main shaft seal pipe by a specially-assigned person, closing a shaft seal overflow regulating valve and a bypass electric door in time, closing the shaft seal until all water in a condenser is drained and immediately breaking vacuum if the shaft seal pressure cannot be maintained due to untimely steam source switching; after the pressure of the auxiliary steam header is stable, when the auxiliary steam header is put into a shaft seal system again, the auxiliary steam header is fully drained, because the temperature of the large machine cylinder is higher at the moment, the pressure and the temperature of the shaft seal (40-50 kPa and 180 ℃) are properly increased, the temperature of each tile shaft seal is carefully checked to be normal, the phenomenon that each tile shaft seal does not suck air is carefully checked after vacuumizing, and the temperature and the eccentricity of the large machine cylinder are carefully checked; arranging and inspecting to open a drainage manual door of a steam turbine cylinder body and drainage manual doors of steam extraction pipelines at all sections; during the starting process, the TSI parameters of the large engine are monitored to be normal, in particular the temperature difference between an upper cylinder and a lower cylinder and the expansion difference between a high pressure cylinder and a medium pressure cylinder.

3. Boiler water feeding: after the shaft seal and the vacuum of the unit are normal, according to the ignition preparation condition of a boiler, a small machine is timely flushed and rotated, the deaerator is thrown in for heating, the temperature rise of the deaerator is noticed, when the front pressure of a main water supply electric door of the boiler is higher than the pressure behind the door by more than 0.5MPa, a water supply bypass electric regulating door is opened, the boiler is slowly supplied with water, the temperature drop rate of an inlet of the economizer (less than 2 ℃/min) is noticed at the moment, when the water level of a water storage tank of a steam-water separator of the boiler is about 6m, a circulating pump of the boiler is started, the opening degree of an outlet regulating door of the circulating pump of the large boiler is opened as much as possible, the circulating flow is increased, and the water supply flow rate of the inlet of the economizer is ensured.

4. Igniting the boiler: starting a draught fan and a delivery fan to purge the boiler, selecting a mill which does not run before MFT occurs after purging is finished to establish a primary fan channel, and starting the primary fan; if the temperature of the secondary hot air is higher than 160 ℃, the air heater can be not put into operation, if the temperature of the secondary hot air is lower than 160 ℃, the air heater is put into operation; note that: when the steam heater is put into operation, the operation needs to be slow, and the change of the pressure of the auxiliary steam header is noticed to influence the steam supply of the shaft seal and the operation of the small machine; and starting the plasma C mill, wherein the arc discharge of the powder pipes one by one is carried out firstly, then the ventilation operation is carried out, after the C coal mill normally operates, the coal feeding amount is properly increased, the temperature of the smoke at the outlet of the hearth is increased to be higher than the wall temperature of the superheater as soon as possible, and if the combustion load of one coal mill is insufficient, and the main steam pressure, the reheating steam pressure and the temperature still quickly decrease, the second coal mill should be started to operate.

5. Boiler temperature rise and pressure rise and auxiliary steam source switching: when the boiler water is near the saturation temperature, the water storage tank of the steam-water separator is easy to generate false water level, the change is violent, the control is not easy, and people with rich experience should be arranged to adjust the boiler feed water to prevent the boiler from tripping along with a pump or the boiler superheater from passing through water; after the pressure and the temperature of the boiler rise again, slowly opening a low bypass, simultaneously opening a large high bypass, keeping the pressure of a reheater stable, opening drain electric doors of a main steam pipeline and a reheated steam pipeline, checking a side drain manual door and measuring the temperature, and increasing the temperature of the main reheated steam to 480-500 ℃ in order to prevent negative temperature difference starting; after the pressure is built again, the steam supply of the auxiliary steam header is switched from the heat supply steam to cold and then steam supply, the auxiliary steam is opened to the manual soot blowing door of the air preheater, and the air preheater is put into the air preheater to continuously blow soot in time. The method comprises the following steps of flushing oxide skins according to the quality condition of steam and water, wherein important users such as cold secondary steam, secondary steam belt shaft seal, small machines and the like pay special attention to monitoring the automatic adjustment condition of high-side temperature reduction water, and controlling the temperature of 280-350 ℃ and the pressure of 0.8-1 MPa after high-side temperature reduction water in the whole process until the high-side temperature reduction water is completely closed after the machine set is connected to the grid; arranging personnel to transfer to another small machine, paying attention to: because the shaft seal putting time of the small machine is too long in the state of stopping running, the warm-up time should be properly prolonged in the process of running (more than 30min is recommended in each stage).

6. The method comprises the following steps of (1) turbine running and grid connection with load: steam turbine impulse parameters: the main steam pressure is 5-6 MPa, the main steam temperature and the reheat steam temperature are 500 ℃, and the main steam pressure and the reheat steam temperature are added randomly after the impact rotation, and attention is paid to: because the cold recompression is higher at the moment, the second-stage steam extraction is slowly opened, and the second-stage steam extraction electric door is kept at a smaller opening; in the process of impact rotation, the temperature adjustment of main reheating steam is enhanced, the steam temperature can only rise but not be allowed to fall, the temperature rise rate of 0.5-1.5 ℃/min is ensured, and water impact is prevented; the monitoring of the TSI parameters of the large engine is enhanced, medium-speed warm-up is not needed during extremely hot starting, the speed is directly increased to 2900rpm after 400rpm friction inspection, and the operation of the engine unit is combined with the network, the state is changed, the steam pump is combined, the load is increased and AGC is put into operation at the rotating speed of 3000 rpm.

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.

Claims (8)

1. The utility model provides an external heat supply unit of condensing steam does not have isolated hot starting system of steam assistance, its characterized in that includes condensing steam formula unit and No. two condensing steam formula units, condensing steam formula unit with No. two condensing steam formula units are connected with heat supply steam distributing cylinder through first pipeline and second pipeline respectively, and are right heat supply steam distributing cylinder provides the vapour source, be connected with the female pipe of heat supply all the way on the heat supply steam distributing cylinder, the female pipe of heat supply carries steam to each heat supply user, be connected with third pipeline and fourth pipeline on the heat supply steam distributing cylinder, heat supply steam distributing cylinder carries steam to unit steam assistance header No. one through the third pipeline, heat supply steam distributing cylinder carries steam to No. two unit steam assistance headers through the fourth pipeline.

2. The isolated thermal starting system of claim 1, wherein the third pipeline is provided with a first manual isolation door and a third electric isolation door.

3. The isolated thermal starting system of claim 2, wherein the third pipeline is provided with a plurality of first hydrophobic points.

4. The isolated thermal starting system of claim 3, wherein the number of the first hydrophobic points is three.

5. The isolated thermal starting system of claim 1, wherein a second manual isolation door and a fourth electric isolation door are disposed on the fourth pipeline.

6. The isolated thermal starting system of claim 5, wherein the fourth pipeline is provided with a plurality of second hydrophobic points.

7. The isolated thermal starting system of claim 6, wherein the number of the second hydrophobic points is four.

8. The isolated thermal starting system of any one of claims 1 to 7, wherein the first and second pipelines are respectively provided with a first and second isolation electric doors.

Images