CN117109017A - Blow pipe system of waste heat boiler of combined cycle unit - Google Patents

Abstract

The invention discloses a combined cycle unit waste heat boiler blow tube system, which comprises a multi-stage steam supply device, a main-way discharge tube group and at least one bypass discharge tube group, wherein the main-way discharge tube group comprises a main-way discharge main tube and a multi-stage main-way purge tube connected with the main-way discharge main tube, the multi-stage main-way purge tube corresponds to and is connected with the multi-stage steam supply device one by one, a main-way purge tube valve and a target plate device are arranged on the main-way purge tube, the bypass discharge tube group comprises a bypass discharge main tube and a multi-stage bypass purge tube connected with the bypass discharge main tube, the multi-stage bypass purge tube corresponds to and is connected with the multi-stage main-way purge tube one by one, and a bypass purge tube valve is arranged on the bypass purge tube. When the target plate is replaced, the bypass blowing pipe valve is opened, so that the pressure born by the target plate device on the main path blowing pipe is reduced, the risk of high-temperature steam leakage faced by operators is reduced, and the safety of target plate replacement operation is improved.

Description

Blow pipe system of waste heat boiler of combined cycle unit

Technical Field

The invention relates to the technical field of gas-steam combined cycle power generation, in particular to a blow pipe system of a waste heat boiler of a combined cycle unit.

Background

The Gas Turbine is an internal combustion type power machine which uses continuously flowing Gas as working medium to drive an impeller to rotate at high speed, converts the energy of fuel into useful work, and is a rotary impeller type heat engine.

The combined cycle unit is provided with the waste heat boiler to recycle the exhaust gas heat of the gas turbine, and the steam produced by the waste heat boiler enters the steam turbine to perform work and power generation, so that the power generation efficiency of the combined cycle system is improved. In the related art, a waste heat boiler with three steam drums of high pressure, medium pressure and low pressure is widely used, and the waste heat boiler is provided with three heating surface systems of high pressure, medium pressure and low pressure. When the steam purging operation of the steam-water pipeline of the waste heat boiler is carried out on site, the water quality of the low-pressure steam drum at the initial stage is poor, the problem of frequent blockage of the filter screen of the water supply pump is easy to occur, and the target plate is replaced by a plurality of steam drums, so that a great safety risk exists.

Disclosure of Invention

The present invention has been made based on the findings and knowledge of the inventors regarding the following facts and problems:

during the power plant capital construction debugging, the newly-built boiler needs to be subjected to pipeline steam purging so as to clean impurities in a steam-water system of the boiler and ensure the cleanliness of steam after production operation. In actual operation, impurity dirt is more in the waste heat boiler low pressure economizer, low pressure evaporator etc. system, leads to the low pressure steam drum in the water quality abominable for it is as the high pressure feed pump of water source, middling pressure feed pump frequently takes place filter screen jam, has to shut down the washing filter screen, leads to waste heat boiler steam blowpipe work to break many times, has seriously influenced the engineering progress.

When the target plate is replaced, the blowpipe valve in each steam pipeline is closed, the pressure of the three steam drums of the waste heat boiler is increased, but the boosting rate and the boosting amplitude are inconsistent, when the pressure of one steam drum is close to the safety limit value, the risk of steam leakage is increased, and the target plate in the steam pipeline is replaced to face larger high-temperature scalding risk.

The present invention aims to solve at least one of the technical problems in the related art to some extent.

Therefore, the embodiment of the invention provides a high-efficiency and safe combined cycle unit waste heat boiler blowpipe system, which is used for solving the problem that a filter screen is frequently blocked by a high-pressure water supply pump and a medium-pressure water supply pump, effectively reducing the pressure of each steam drum during the replacement of a target plate and ensuring the operation safety of field personnel.

The exhaust-heat boiler blowpipe system of the combined cycle unit comprises: the multi-stage steam supply device, main way discharging pipe group and at least one bypass discharging pipe group, wherein the steam supply device is used for utilizing working medium water to produce saturated steam, the main way discharging pipe group comprises a main way discharging main pipe and a multi-stage main way purging pipe connected with the main way discharging main pipe, the multi-stage main way purging pipe corresponds to the multi-stage steam supply device one by one and is connected with the steam supply device, the main way purging pipe is used for conveying the saturated steam generated by the steam supply device corresponding to the main way purging pipe and discharging the saturated steam into the atmosphere through the main way discharging main pipe, the main way purging pipe is provided with a main way purging valve and a target plate device which are arranged at intervals from upstream to downstream in the steam flow direction, the bypass discharging pipe group comprises a bypass discharging main pipe and a multi-stage bypass purging pipe connected with the bypass discharging main pipe, the bypass purging pipe corresponds to the multi-stage main way purging pipe one by one and is connected with the main way purging pipe, the bypass purging pipe is connected with the main way purging pipe corresponding to the main way purging pipe one by one, the bypass pipe is positioned at the upstream of the steam flow direction of the main way purging pipe and is provided with the bypass purging pipe valve corresponding to the bypass discharging main pipe.

According to the exhaust-heat boiler blowpipe system of the combined cycle unit, when the target plate is replaced, the bypass blowpipe valve on the bypass blowpipe connected with the main-path blowpipe where the target plate device is located is opened, and the pressure of the corresponding steam supply device is released, so that the steam pressure in the main-path blowpipe is less than 1MPa, the pressure born by the target plate device on the main-path blowpipe is reduced, the risk of high-temperature steam leakage faced by operators is reduced, and the safety of target plate replacement operation is improved.

In some embodiments, the multi-stage steam supply device comprises a low-pressure steam supply device, a medium-pressure steam supply device and a high-pressure steam supply device, the multi-stage main path purging pipe comprises a low-pressure main path purging pipe connected with the low-pressure steam supply device, a medium-pressure main path purging pipe connected with the medium-pressure steam supply device and a high-pressure main path purging pipe connected with the high-pressure steam supply device, and the multi-stage bypass purging pipe comprises a low-pressure bypass purging pipe connected with the low-pressure main path purging pipe, a medium-pressure bypass purging pipe connected with the medium-pressure main path purging pipe and a high-pressure bypass purging pipe connected with the high-pressure main path purging pipe.

In some embodiments, the low-pressure steam supply device comprises a condensate pump, a low-pressure economizer, a low-pressure steam drum and a low-pressure superheater which are connected in sequence through pipelines, and the low-pressure main-path purging pipe is connected with the low-pressure superheater.

In some embodiments, the medium pressure steam supply device comprises a medium pressure water supply pump, a medium pressure economizer, a medium pressure steam drum and a medium pressure superheater which are connected in sequence through pipelines, and the medium pressure main path purging pipe is connected with the medium pressure superheater.

In some embodiments, the high-pressure steam supply device comprises a high-pressure feed pump, a high-pressure economizer, a high-pressure steam drum and a high-pressure superheater which are sequentially connected through pipelines, the high-pressure main-path purging pipe is connected with the high-pressure superheater, the high-pressure main-path purging pipe is further provided with a high-pressure main steam valve, a reheater and a medium-pressure main steam valve which are positioned on the main-path purging pipe at the upstream of the main-path purging pipe in the steam flow direction, the high-pressure main steam valve, the reheater and the medium-pressure main steam valve are arranged at intervals from the upstream to the downstream in the steam flow direction, the combined cycle unit waste heat boiler blowing pipe system further comprises a first branch pipe, the first branch pipe is connected with the medium-pressure main-path purging pipe and the high-pressure main-path purging pipe, the connection of the first branch pipe and the medium-pressure main-path purging pipe is positioned on the main-path purging pipe at the upstream of the main-path purging pipe in the steam flow direction, and the connection of the first branch pipe and the high-pressure main-path purging pipe is positioned between the high-pressure main-path purging pipe and the medium-pressure main-path purging pipe.

In some embodiments, the connection of the high pressure bypass purge pipe to the high pressure main purge pipe is upstream of the high pressure main steam valve in the steam flow direction.

In some embodiments, the medium pressure bypass purge pipe is connected to the high pressure main purge pipe such that the medium pressure bypass purge pipe is connected to the medium pressure main purge pipe via the high pressure main purge pipe and the first branch pipe.

In some embodiments, the connection of the intermediate pressure bypass purge pipe and the high pressure main purge pipe is located between the reheater and the intermediate pressure main steam valve in the steam flow direction.

In some embodiments, the combined cycle unit waste heat boiler blowpipe system further comprises a water supplementing pipe set, wherein the water supplementing pipe set comprises a water supplementing mother pipe, a first water supplementing sub pipe and a second water supplementing sub pipe, the first water supplementing sub pipe and the second water supplementing sub pipe are connected with the water supplementing mother pipe, the water supplementing mother pipe is connected with the low-pressure steam drum, the first water supplementing sub pipe is connected with the medium-pressure water supply pump, and the second water supplementing sub pipe is connected with the high-pressure water supply pump.

In some embodiments, the combined cycle unit waste heat boiler blowpipe system further comprises a second branch pipe, the second branch pipe is connected with the water replenishing mother pipe and a pipeline between the condensate pump and the low-pressure economizer, a first water replenishing valve is arranged on the water replenishing mother pipe, the connection of the second branch pipe and the water replenishing mother pipe is located at the downstream of the first water replenishing valve in the steam flow direction, and a second water replenishing valve is arranged on the second branch pipe.

Drawings

FIG. 1 is a schematic diagram of a combined cycle unit waste heat boiler lance system in accordance with an embodiment of the present invention.

Reference numerals:

condensate pump 11, low pressure economizer 12, low pressure drum 13, low pressure superheater 14,

A medium pressure water feed pump 21, a medium pressure economizer 22, a medium pressure steam drum 23, a medium pressure superheater 24,

A high-pressure water feed pump 31, a high-pressure economizer 32, a high-pressure steam drum 33, a high-pressure superheater 34,

Main discharge main pipe 41, main muffler 411, low-pressure main purge pipe 42, low-pressure main purge pipe valve 421, low-pressure target plate 422, medium-pressure main purge pipe 43, medium-pressure main purge pipe valve 431, medium-pressure target plate 432, high-pressure main purge pipe 44, high-pressure main purge pipe valve 441, high-pressure target plate 442, high-pressure main steam valve 443, reheater 444, medium-pressure main steam valve 445,

A bypass discharge header 51, a bypass muffler 511, a low pressure bypass purge pipe 52, a low pressure bypass purge pipe 521, a medium pressure bypass purge pipe 53, a medium pressure bypass purge pipe 531, a high pressure bypass purge pipe 54, a high pressure bypass purge pipe 541, a high pressure bypass purge pipe,

A water supplementing mother pipe 61, a first water supplementing valve 611, a first water supplementing son pipe 62, a second water supplementing son pipe 63,

A first branch pipe 71, a second branch pipe 72, and a second water compensating valve 721.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

The following describes a blow pipe system of a waste heat boiler of a combined cycle unit according to an embodiment of the present invention with reference to the accompanying drawings.

As shown in fig. 1, a blow pipe system of a combined cycle unit waste heat boiler according to an embodiment of the present invention includes: a multi-stage steam supply device, a main drain pipe group and at least one bypass drain pipe group.

The steam supply device is externally connected with a water source, and saturated steam is generated by three processes of heating, evaporating and superheating working medium water.

The main-path exhaust pipe group comprises a main-path exhaust main pipe 41 and a multi-stage main-path purging pipe, wherein the output end of the exhaust main pipe is communicated with the atmosphere, and the input end of the exhaust main pipe is connected with the output end of the multi-stage main-path purging pipe through a multi-way valve (not shown in the figure). The multi-stage main-path purging pipes are in one-to-one correspondence with and connected to the multi-stage steam supply devices, and are used for conveying saturated steam generated by the steam supply devices corresponding to the multi-stage main-path purging pipes and discharging the saturated steam into the atmosphere through the main-path discharging main pipe 41. The main-path purging pipe is provided with a main-path blowing pipe valve and a target plate device which are arranged at intervals from upstream to downstream in the steam flow direction.

The bypass discharge pipe group includes a bypass discharge main pipe 51 and a multistage bypass purge pipe, an output end of the discharge main pipe is connected to the atmosphere, and an input end of the discharge main pipe is connected to an output end of the multistage bypass purge pipe through a multi-way valve (not shown). The multi-stage bypass purging pipes are in one-to-one correspondence with and connected with the multi-stage main purging pipes, the connection between the bypass purging pipes and the main purging pipes corresponding to the bypass purging pipes is located at the upstream of the main purging pipe valve in the steam flow direction, the bypass purging pipes are used for conveying saturated steam in the main purging pipes corresponding to the bypass purging pipes and discharging the saturated steam into the atmosphere through the bypass discharging main pipe 51, and the bypass purging pipes are provided with bypass purging pipes.

It is understood that the blowpipe valve is an electric valve with the switching time meeting certain requirements and is used for controlling the on-off of the purge steam. The target plate device is a strip-shaped target plate fixing device, the target plate is a copper plate or an aluminum plate with a certain width and smaller hardness, and the length of the target plate device traverses the whole section of the steam pipeline. If there are foreign particles in the vapor, then a pit will be struck on the target plate, based on which the target plate device can be used to verify the final stage purge effect of the torch.

And in the steam blowing pipe stage, a blowing pipe valve on each pipeline in the system is in a closed state, working media in each steam supply device are heated and boosted after the waste heat boiler absorbs heat, and when the pressure reaches the set pressure, a main blowing pipe valve on a corresponding main blowing pipe is opened for steam pressure relief blowing.

If a plurality of steam supply devices are pressurized to the respective purging pressure simultaneously and pressure relief is needed, the main path blow pipe valve of the main path purging pipe of any steam supply device can be opened, the bypass blow pipe valve of any bypass purging pipe of another steam supply device is opened, and the bypass blow pipe valve of another bypass purging pipe of another steam supply device is opened, so that the steam supply devices correspond to different discharge main pipes, and the steam discharge of the steam supply devices are not affected.

For example, when both steam supply devices need to release pressure, if both steam supply devices exhaust steam through the same main exhaust pipe, the steam with high pressure will return to the steam with low pressure, and the impurities will be blown back into the purge pipe with low pressure. Therefore, the main path purge pipe valve of the main path purge pipe can be opened, the main path discharge main pipe 41 is utilized to discharge and release steam for one steam supply device, the bypass purge pipe valve of the bypass purge pipe is opened, and the bypass discharge main pipe 51 is utilized to discharge and release steam for the other steam supply device, so that the mutual influence of the steam discharge of the main path purge pipe and the bypass purge pipe is avoided.

And when one steam supply device needs to release pressure, the main path blow pipe valve of the main path blow pipe connected with the steam supply device and the bypass blow pipe valve of the bypass blow pipe correspondingly connected with the main path blow pipe valve can be opened at the same time, so that the pressure of the steam supply device is quickly released, and the pressure-reducing blowing effect is improved.

Further, the main muffler 411 is provided at the output end of the main discharge main pipe 41, and the bypass muffler 511 is provided at the output end of the bypass discharge main pipe 51, for reducing noise at the time of high-temperature steam discharge.

After the pressure reduction and blowing are carried out for a plurality of times, the impurity dirt in the discharge pipe group is basically cleaned, and the cleanliness of steam is checked by placing a corresponding target plate in the target plate device.

When the target plate is replaced, the bypass blowing pipe valve on the bypass blowing pipe connected with the main blowing pipe where the target plate device is located is opened, and the pressure of the corresponding steam supply device is released, so that the steam pressure in the main blowing pipe is less than 1MPa, the pressure born by the target plate device on the main blowing pipe is reduced, the high-temperature steam leakage risk faced by operators is reduced, and the safety of target plate replacement operation is improved.

In some embodiments, as shown in fig. 1, the multi-stage steam supply device includes a low pressure steam supply device, a medium pressure steam supply device, and a high pressure steam supply device.

The multi-stage main purge pipe includes a low pressure main purge pipe 42, a medium pressure main purge pipe 43, and a high pressure main purge pipe 44. The input end of the low-pressure main-path purging pipe 42 is connected with a low-pressure steam supply device, the input end of the medium-pressure main-path purging pipe 43 is connected with a medium-pressure steam supply device, and the input end of the high-pressure main-path purging pipe 44 is connected with a high-pressure steam supply device. The output ends of the low-pressure main-path purging pipe 42, the medium-pressure main-path purging pipe 43 and the high-pressure main-path purging pipe 44 are connected with the input end of the main-path discharging main pipe 41.

The main-way pipe valve and the target plate device on the low-pressure main-way purging pipe 42 are respectively a low-pressure main-way pipe valve 421 and a low-pressure target plate device 422, the main-way pipe valve and the target plate device on the medium-pressure main-way purging pipe 43 are respectively a medium-pressure main-way pipe valve 431 and a medium-pressure target plate device 432, and the main-way pipe valve and the target plate device on the high-pressure main-way purging pipe 44 are respectively a high-pressure main-way pipe valve 441 and a high-pressure target plate device 442.

The multi-stage bypass purge pipe includes a low pressure bypass purge pipe 52, a medium pressure bypass purge pipe 53, and a high pressure bypass purge pipe 54. The input end of the low-pressure bypass purge pipe 52 is connected with the low-pressure main purge pipe 42, the input end of the medium-pressure bypass purge pipe 53 is connected with the medium-pressure main purge pipe 43, and the input end of the high-pressure bypass purge pipe 54 is connected with the high-pressure main purge pipe 44. The outputs of the low pressure bypass purge pipe 52, the medium pressure bypass purge pipe 53 and the high pressure bypass purge pipe 54 are all connected to the input of the bypass discharge main pipe 51.

The bypass purge valve on the low pressure bypass purge pipe 52 is a low pressure bypass purge valve 521, the bypass purge valve on the medium pressure bypass purge pipe 53 is a medium pressure bypass purge valve 531, and the bypass purge valve on the high pressure bypass purge pipe 54 is a high pressure bypass purge valve 541.

Alternatively, as shown in fig. 1, the low pressure steam supply device includes a condensate pump 11, a low pressure economizer 12, a low pressure steam drum 13, and a low pressure superheater 14. The input end of the condensate pump 11 is connected with a water source through a pipeline, the output end of the condensate pump 11 is connected with the input end of the low-pressure economizer 12 through a pipeline, the output end of the low-pressure economizer 12 is connected with the input end of the low-pressure steam drum 13 through a pipeline, the output end of the low-pressure steam drum 13 is connected with the input end of the low-pressure superheater 14 through a pipeline, and the output end of the low-pressure superheater 14 is connected with the input end of the low-pressure purging pipe.

As shown in fig. 1, the medium pressure steam supply device includes a medium pressure feed pump 21, a medium pressure economizer 22, a medium pressure steam drum 23, and a medium pressure superheater 24. The input end of the medium pressure water supply pump 21 is connected with a water source through a pipeline, the output end of the medium pressure water supply pump 21 is connected with the input end of the medium pressure economizer 22 through a pipeline, the output end of the medium pressure economizer 22 is connected with the input end of the medium pressure steam drum 23 through a pipeline, the output end of the medium pressure steam drum 23 is connected with the input end of the medium pressure superheater 24 through a pipeline, and the output end of the medium pressure superheater 24 is connected with the input end of the medium pressure purging pipe.

As shown in fig. 1, the high-pressure steam supply device includes a high-pressure feed pump 31, a high-pressure economizer 32, a high-pressure steam drum 33, and a high-pressure superheater 34. The input end of the high-pressure water supply pump 31 is connected with a water source through a pipeline, the output end of the high-pressure water supply pump 31 is connected with the input end of the high-pressure economizer 32 through a pipeline, the output end of the high-pressure economizer 32 is connected with the input end of the high-pressure steam drum 33 through a pipeline, the output end of the high-pressure steam drum 33 is connected with the input end of the high-pressure superheater 34 through a pipeline, and the output end of the high-pressure superheater 34 is connected with the input end of the high-pressure purging pipe.

The high, medium and low pressure steam drums 13 are used as connecting hinges for three processes of heating, evaporating and overheating working medium water, and are used as a balancer to ensure a pressure head required by water-cooled wall circulation, and are provided with a steam-water separation device to ensure the quality of saturated steam. The steam blowing pipe stage steam supply device needs pressure relief, namely the pressure relief is needed when the working medium in the steam drum reaches the set pressure.

The high, medium and low pressure economizers 12 are used to absorb heat from the exhaust of the combustion engine and heat the feed water into the drum. The medium-pressure water supply pump 31, the high-pressure water supply pump 11 and the condensate pump 11 are used for driving working medium water to flow through respective economizers and finally enter corresponding steam drums, and the heat absorption and evaporation processes are completed in the water supply flow process. The high, medium and low pressure superheaters 14 are used for further superheating saturated steam discharged from the corresponding steam drum to a set temperature, so as to meet the working condition requirements of the steam turbine.

Further, as shown in fig. 1, the high-pressure main purge pipe 44 is further provided with a high-pressure main steam valve 443, a reheater 444 and an intermediate-pressure main steam valve 445 upstream of the high-pressure main purge pipe valve 441 in the steam flow direction, and the high-pressure main steam valve 443, the reheater 444 and the intermediate-pressure main steam valve 445 are arranged at intervals from upstream to downstream in the steam flow direction.

In addition, the exhaust-heat boiler blow tube system of the combined cycle unit further comprises a first branch tube 71, wherein the input end of the first branch tube 71 is connected with the medium-pressure main-path purge tube 43, the output end of the first branch tube 71 is connected with the high-pressure main-path purge tube 44, the connection position of the first branch tube 71 and the medium-pressure main-path purge tube 43 is located at the upstream of the medium-pressure main-path blow tube valve 431 in the steam flow direction, and the connection position of the first branch tube 71 and the high-pressure main-path purge tube 44 is located between the high-pressure main steam valve 443 and the reheater 444 in the steam flow direction.

Specifically, as shown in FIG. 1, the connection of the high pressure bypass purge pipe 54 to the high pressure main purge pipe 44 is upstream of the high pressure main steam valve 443 in the steam flow direction. The input end of the intermediate pressure bypass purge pipe 53 is connected to the high pressure main purge pipe 44 so that the intermediate pressure bypass purge pipe 53 is connected to the intermediate pressure main purge pipe 43 via the high pressure main purge pipe 44 and the first branch pipe 71. The connection of the intermediate pressure bypass purge pipe 53 to the high pressure main purge pipe 44 is located between the reheater 444 and the intermediate pressure main steam valve 445 in the steam flow direction.

In some embodiments, as shown in fig. 1, the exhaust-heat boiler blow pipe system of the combined cycle unit according to the embodiment of the present invention further includes a water supplementing pipe set, where the water supplementing pipe set includes a water supplementing nut pipe 61, a first water supplementing sub-pipe 62 and a second water supplementing sub-pipe 63, an input end of the water supplementing nut pipe 61 is connected to the low pressure steam drum 13, an output end of the water supplementing nut pipe 61 is connected to an input end of the first water supplementing sub-pipe 62 and an input end of the second water supplementing sub-pipe 63 through a three-way valve (not shown), an output end of the first water supplementing sub-pipe 62 is connected to an input end of the medium pressure water feed pump 21, and an output end of the second water supplementing sub-pipe 63 is connected to an input end of the high pressure water feed pump 31.

Further, as shown in fig. 1, the exhaust-heat boiler blow pipe system of the combined cycle unit according to the embodiment of the present invention further includes a second branch pipe 72, an input end of the second branch pipe 72 is connected to a pipeline between the condensate pump 11 and the low-pressure economizer 12, and an output end of the second branch pipe 72 is connected to the water replenishment pipe 61. The water replenishment pipe 61 is provided with a first water replenishment valve 611, the connection between the second branch pipe 72 and the water replenishment pipe 61 is located downstream of the first water replenishment valve 611 in the steam flow direction, and the second branch pipe 72 is provided with a second water replenishment valve 721.

It will be appreciated that, at the initial stage of cold flushing, the low-pressure steam drum 13 has a large amount of impurities, and if water in the low-pressure steam drum 13 is directly used as a water source of the medium-pressure water feed pump 21 and the high-pressure water feed pump 31, the inlet filter screens of the medium-pressure water feed pump 21 and the high-pressure water feed pump 31 are frequently blocked, so that the cold flushing of the waste heat boiler cannot be continuously performed, and the construction period of the stage is prolonged. In addition, the low pressure drum 13 is used as a water source for the medium pressure water feed pump 21 and the high pressure water feed pump 31, so that the medium pressure and high pressure equipment is flushed by the dirty water flushed by the low pressure drum 13, and the cleaning effect is poor.

Thus, in the combined cycle unit waste heat boiler blowpipe system of the embodiment of the invention, the first water supplementing valve 611 is closed and the second water supplementing valve 721 is opened at the initial stage of cold flushing. By means of the condensate pump 11, water is fed to the low-pressure steam drum 13 through the low-pressure economizer 12, and when the water level of the low-pressure steam drum 13 reaches about + -100 mm, a drain valve (not shown in the figure) of the low-pressure steam drum 13 is opened to start draining. By adjusting the output of the condensate pump 11 and the opening of the drain valve of the low pressure steam drum 13, the balance between the water supply amount and the drain amount can be controlled, so that the low pressure steam drum 13 is always in the normal liquid level range.

The medium pressure water feed pump 21 and the high pressure water feed pump 31 pump condensed water with clean water quality through the second branch, water feeding and flushing are carried out on the medium pressure steam drum 23 and the high pressure steam drum 33, the opening degree of respective blow-down valves is controlled, sewage is discharged while water is discharged, the liquid level of the medium pressure steam drum 23 and the high pressure steam drum 33 is maintained within +/-300 mm, the possibility of blocking inlet filter screens of the medium pressure water feed pump 21 and the high pressure water feed pump 31 is eliminated, and the cleaning effect of medium pressure and high pressure equipment is greatly improved.

In the hot flushing stage, after the gas turbine is ignited, water in the boiler is heated, so that the solubility of impurities such as scrap iron scale and the like is high, and the flushing capability is improved. At this stage, as with the cold flush, the first and second water replenishment valves 611 and 721 are utilized to allow the condensate pump 11, the medium pressure feedwater pump 21, and the high pressure feedwater pump 31 to each utilize clean condensate as a source of water for the low, medium, and high pressure equipment to be hot flushed and the contaminated water to be discharged from the system through the respective blowdown valves. Until the low pressure, medium pressure and high pressure steam drums 33 are used for water taking test, the water quality reaches the standard (the concentration of iron ions, silicon ions and the like in the water meets the regulation specification requirements), and the hot flushing is finished.

In the related art, the thermal state flushing process is set to the end temperature, and then the working medium in the steam drum is continuously heated to the set temperature. The embodiment of the invention provides a blowing pipe system of a waste heat boiler of a combined cycle unit, and provides a sectional temperature control and pressure control flushing method for a specific hot flushing method. In the process of converting the low-pressure, medium-pressure and high-pressure steam drums from a cold state to a hot state, the water temperature control in the steam drums is divided into four stages T1-T4, and in the heating process of each stage, the pressure of the steam drums follows the pressure rising rate of P1-P4. The method comprises the following steps:

the first stage: t1=115 ℃, Δp1=0.02 MPa/min, and the final pressure p1=0.17 MPa. When the actual water temperature T is more than T1, the water feeding amount is increased to control the temperature of the working medium in the steam drum to be stable. When the actual pressure increasing rate Deltap > DeltaP1, the water discharge amount is increased, a drum exhaust valve and a drainage system (not shown in the figure) are opened, and the pressure release amount is increased so as to control the pressure stability of working media in the drum. The T1 parameter is kept for 3.0-4.0 hours at the stage, and normal water supply and drainage flushing work is carried out during the period.

And a second stage: t2=135 ℃, Δp2=0.05 MPa/min, and the final pressure p2=0.32 MPa. When the actual water temperature T is more than T2, the water feeding amount is increased to control the temperature of the working medium in the steam drum to be stable. When the actual pressure increasing rate Deltap > DeltaP2, the water discharge amount is increased, the drum exhaust valve and the drainage system are opened, and the pressure release amount is increased so as to control the pressure stability of the working medium in the drum. The T2 parameter is kept for 2.5-3.5 hours at the stage, and normal water supply and drainage flushing work is carried out during the period.

And a third stage: t3=170 ℃, Δp3=0.03 MPa/min, p3=0.8 MPa, duration 2.0-3.0 hours. The over-temperature and over-pressure control method is the same as the above steps.

Fourth stage: t4=190 ℃, Δp4=0.03 MPa/min, p4=1.3 MPa, duration 2.0-3.0 hours. The over-temperature and over-pressure control method is the same as the above steps.

After the sectional heating flushing process, the water quality in the steam drum is faster than the flushing improvement rate of the traditional linear heating mode, and the flushing efficiency is greatly improved.

After the thermal state flushing is finished, the waste heat boiler enters a steam purging stage. To meet the requirement that the water stored in the drum is largely evaporated and a large amount of water is needed in this stage, the second water supplementing valve 721 is closed, the first water supplementing valve 611 is opened, and the water sources of the medium-pressure water feed pump 21 and the high-pressure water feed pump 31 are switched to the low-pressure drum 13. The low-pressure steam drum 13 is basically clean in the interior after cold flushing and hot flushing, and the water quality can meet the requirement that the inlet filter screens of the medium-pressure water feed pump 21 and the high-pressure water feed pump 31 are not blocked.

In summary, the exhaust-heat boiler blowpipe system of the combined cycle unit of the embodiment of the invention solves the problem of blockage of inlet filter screens of the medium-pressure water feed pump 21 and the high-pressure water feed pump 31 in the cold flushing stage caused by poor water quality in the low-pressure steam drum 13 by utilizing the water supplementing pipe group and the second branch. And moreover, the main-way exhaust pipe group and the bypass exhaust pipe group are separately arranged, so that the pressure in the steam pipeline can be regulated and controlled in the replacement process of the target plate device, and the safety of operation is ensured.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

For purposes of this disclosure, the terms "one embodiment," "some embodiments," "example," "a particular example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While the above embodiments have been shown and described, it should be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives, and variations of the above embodiments may be made by those of ordinary skill in the art without departing from the scope of the invention.

Claims (10)

1. A combined cycle unit waste heat boiler lance system comprising:

the multi-stage steam supply device is used for generating saturated steam by using working medium water;

the main way exhaust pipe group comprises a main way exhaust main pipe and a multi-stage main way purging pipe connected with the main way exhaust main pipe, the multi-stage main way purging pipe is in one-to-one correspondence with and is connected with the multi-stage steam supply device, the main way purging pipe is used for conveying saturated steam generated by the steam supply device corresponding to the main way purging pipe and exhausting the saturated steam into the atmosphere through the main way exhaust main pipe, and the main way purging pipe is provided with main way purging valves and target plates which are arranged at intervals from upstream to downstream in the steam flow direction;

the bypass exhaust pipe group comprises a bypass exhaust main pipe and a multi-stage bypass purge pipe connected with the bypass exhaust main pipe, the multi-stage bypass purge pipe corresponds to the main purge pipe one by one and is connected with the main purge pipe, the connection of the bypass purge pipe and the main purge pipe corresponding to the bypass purge pipe is positioned at the upstream of the main purge pipe valve in the steam flow direction, the bypass purge pipe is used for conveying saturated steam in the main purge pipe corresponding to the bypass purge pipe and discharging the saturated steam into the atmosphere through the bypass exhaust main pipe, and the bypass purge pipe is provided with a bypass purge pipe valve.

2. The combined cycle unit waste heat boiler blow tube system according to claim 1, wherein the multi-stage steam supply device comprises a low-pressure steam supply device, a medium-pressure steam supply device and a high-pressure steam supply device, the multi-stage main-path blow tube comprises a low-pressure main-path blow tube connected with the low-pressure steam supply device, a medium-pressure main-path blow tube connected with the medium-pressure steam supply device and a high-pressure main-path blow tube connected with the high-pressure steam supply device, and the multi-stage bypass blow tube comprises a low-pressure bypass blow tube connected with the low-pressure main-path blow tube, a medium-pressure bypass blow tube connected with the medium-pressure main-path blow tube and a high-pressure bypass blow tube connected with the high-pressure main-path blow tube.

3. The combined cycle unit waste heat boiler blow pipe system according to claim 2, wherein the low pressure steam supply device comprises a condensate pump, a low pressure economizer, a low pressure steam drum and a low pressure superheater which are connected in sequence through pipelines, and the low pressure main purge pipe is connected with the low pressure superheater.

4. The combined cycle unit waste heat boiler blowpipe system of claim 3, wherein the medium pressure steam supply device comprises a medium pressure feed pump, a medium pressure economizer, a medium pressure steam drum and a medium pressure superheater connected in sequence by pipelines, and the medium pressure main path purge pipe is connected with the medium pressure superheater.

5. The combined cycle unit waste heat boiler blow tube system according to claim 4, wherein the high pressure steam supply device comprises a high pressure feed pump, a high pressure economizer, a high pressure steam drum and a high pressure superheater which are connected in sequence through pipelines, the high pressure main purge tube is connected with the high pressure superheater, the high pressure main purge tube is further provided with a high pressure main steam valve, a reheater and a medium pressure main steam valve which are positioned upstream of a main pipeline valve on the high pressure main purge tube in the steam flow direction, the high pressure main steam valve, the reheater and the medium pressure main steam valve are arranged at intervals from upstream to downstream in the steam flow direction, the combined cycle unit waste heat boiler blow tube system further comprises a first branch tube which is connected with the medium pressure main purge tube and the high pressure main purge tube, the connection of the first branch tube and the medium pressure main pipeline tube is positioned upstream of the main pipeline valve on the main pipeline valve in the steam flow direction, and the connection of the first branch tube and the high pressure main tube is positioned between the high pressure main purge tube and the high pressure main purge tube.

6. The combined cycle unit waste heat boiler lance system of claim 5 wherein the connection of the high pressure bypass purge pipe to the high pressure main purge pipe is upstream of the high pressure main steam valve in the direction of steam flow.

7. The combined cycle unit waste heat boiler lance system of claim 5 wherein the medium pressure bypass purge pipe is connected to the high pressure main purge pipe such that the medium pressure bypass purge pipe is connected to the medium pressure main purge pipe via the high pressure main purge pipe and the first branch pipe.

8. The combined cycle unit waste heat boiler lance system of claim 7, wherein the connection of the intermediate pressure bypass purge pipe and the high pressure main purge pipe is located in the steam flow direction between the reheater and the intermediate pressure main steam valve.

9. The combined cycle unit waste heat boiler lance system of any one of claims 5-8, further comprising a water make-up tube set comprising a water make-up parent tube and first and second water make-up child tubes connected to the water make-up parent tube, the water make-up parent tube connected to the low pressure steam drum, the first water make-up child tube connected to the medium pressure feed pump, and the second water make-up child tube connected to the high pressure feed pump.

10. The combined cycle unit waste heat boiler blow pipe system according to claim 9, further comprising a second branch pipe, wherein the second branch pipe is connected with the water replenishing main pipe and a pipeline between the condensate pump and the low-pressure economizer, a first water replenishing valve is arranged on the water replenishing main pipe, the connection between the second branch pipe and the water replenishing main pipe is located at the downstream of the first water replenishing valve in the steam flow direction, and a second water replenishing valve is arranged on the second branch pipe.