CN106051737B

CN106051737B - Adjustable feedwater backheating system and control method

Info

Publication number: CN106051737B
Application number: CN201610611250.8A
Authority: CN
Inventors: 冯伟忠
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-07-30
Filing date: 2016-07-30
Publication date: 2024-07-26
Anticipated expiration: 2036-07-30
Also published as: CN106051737A

Abstract

The invention discloses an adjustable feedwater backheating system for a thermal power plant, which comprises a high-pressure cylinder of a steam turbine, a conventional final-stage steam extraction port and a conventional final-stage feedwater heater which are arranged on the high-pressure cylinder, at least one steam cooler, an adjustable final-stage steam extraction port which is arranged on the high-pressure cylinder and has the additional steam extraction pressure far higher than that of the conventional final-stage steam extraction, an adjustable final-stage feedwater heater which takes the additional adjustable final-stage steam extraction as a heat source, and a steam extraction pipeline which is connected with the additional adjustable final-stage steam extraction port and the adjustable final-stage feedwater heater, and an adjustable steam extraction regulating valve arranged on the steam extraction pipeline. The final water supply temperature under different loads is regulated by controlling the additional adjustable last stage steam extraction regulating valve, so that the safe operation, the environmental protection performance and the economical efficiency of the equipment can be considered.

Description

Adjustable feedwater backheating system and control method

Technical Field

The invention relates to the field of thermal power generation, in particular to an adjustable water supply regenerative system for a thermal power plant and a control method.

Background

At present, energy conservation and emission reduction become strategic tasks for the development of economy and society in China. Reducing pollution and improving environment are urgent. Coal power is a main power generation mode in China at present and is a main air pollution source, so that the coal-fired power plant adopts a corresponding pollutant emission reduction technology to further control the influence of the coal-fired power plant on the air. The denitration technology mainly adopts an SCR method (selective catalytic reduction method), and is the most widely used and mature flue gas denitration technology internationally. By adopting the SCR method for denitration, the SCR working smoke temperature cannot be maintained when the boiler is in low-load operation. The SCR has to be taken out of operation, but at this point the NOx production concentration of the boiler is up to 2-3 times the rated load. This means that SCR cannot be used instead in cases where denitration is more desirable. Therefore, the chinese patent with application number CN201110459533.2 discloses an adjustable feedwater heat recovery system, that is, compared with the traditional turbo generator set, the final steam extraction pressure set on the high-pressure cylinder is higher than the highest steam extraction pressure of the conventional high-pressure cylinder; and a steam extraction regulating valve is arranged on the final stage steam extraction pipeline, and then the water is regenerated through a water supply heater. In the running process, the final stage steam extraction can be regulated through the valve, so that the pressure after the steam extraction regulating valve is kept basically unchanged when the unit changes load, and the temperature of the feed water of the boiler is kept basically unchanged through the final stage feed water heater; thus, the problem that the traditional low-load SCR needs to be out of operation is solved. Meanwhile, the chinese patent with application number CN201420700957.2 is based on the above, and the final stage steam extraction port of the high pressure cylinder is set to be adjustable, so that design optimization can be performed according to actual needs, and on the premise that the safety can be met by additionally arranging the final stage steam extraction port, the final stage steam extraction port can be optimally selected according to the running load condition of the unit and the actual needs such as the lifting denitration inlet smoke temperature required to be achieved under low load. In addition, a water supply bypass is arranged for the final stage water supply heater, so that the final stage water supply heater can be arranged into a heater with partial water supply capacity instead of a heater with full water supply capacity, the cost of the final stage water supply heater can be reduced, and the final stage water supply heater can be realized on the existing manufacturing process for some high-parameter large units, and meanwhile, the cost is reduced.

In fact, it is not a necessary condition to maintain the feed water temperature of the variable load units substantially unchanged, on the one hand, the requirements of the feed water temperature rise are also inconsistent for different units under different loads. On the other hand, if the water supply temperature is maintained at a relatively high low load under certain boundary conditions, the partial economy and safety of the unit may be sacrificed.

Firstly, after the low load and the relative increase of the water supply temperature, if the area of the heating surface of the boiler is not correspondingly increased, the corresponding increase of the exhaust gas temperature of the boiler can be caused, and if the boiler is not provided with a corresponding flue gas waste heat recycling system, or the recycling degree is not enough, the partial economy of the unit can be sacrificed.

Secondly, for the boiler provided with the non-boiling type economizer, the excessive water supply temperature under low load easily causes the economizer to generate boiling, so that the water power problem of the water cooling wall is caused, the water cooling wall pipe is dry-burned under serious conditions, and finally the pipe explosion phenomenon is generated.

In addition, if the water supply temperature of the unit is to be maintained to be basically unchanged under different loads, the steam source parameters of the final steam extraction port are higher, so that the unit still has higher steam extraction pressure under low loads, and the water supply temperature of the unit under low loads and high loads can be maintained to be basically unchanged. For example, some turbine models currently employ a steam-compensating valve technology, which has a steam-compensating port as the last-stage steam-extracting port (generally after the 5 th stage of the high-pressure cylinder), and because of its higher parameters, it still has higher steam-extracting pressure under low load, so that even when the unit is as low as 40% load, it still has higher steam-extracting pressure, and the water-feeding temperature can be maintained substantially unchanged. However, this results in a large throttling loss of the final extraction control valve at high loads of the unit, which compromises a part of the unit economy. Therefore, from the optimization perspective of the final stage steam extraction port, the lifting amount of the water supply temperature is directly related to the final stage steam extraction parameter, so that the water supply temperature is basically unchanged under different loads to maintain the unit, and the optimization of the final stage steam extraction port is not favored.

In summary, the water supply temperature rise of the adjustable water supply regenerative system needs to comprehensively consider the three factors, and control and set according to different requirements of water supply temperature rise.

Disclosure of Invention

In view of this, the present invention provides an adjustable feedwater heat recovery system and a control method thereof, which can control and set the water supply temperature rise of the unit under different loads according to the configuration systems of different adjustable feedwater heat recovery systems. On the premise of ensuring the safe operation of the equipment, the optimization of the economy and the environmental protection of the unit is realized.

The invention provides an adjustable water supply regenerative system and a control method, which are characterized in that: based on the existing Chinese patent with the application number of CN201110459533.2 and the existing Chinese patent with the application number of CN201420700957.2, the control mode is broken through and optimized, and is not limited to the control mode of maintaining the water supply temperature under different loads basically unchanged. But comprehensively considers the selection of the additional adjustable final stage steam extraction port. The reasonable selection of the additional adjustable final stage steam extraction port relates to the operation load of a unit, the configuration of the capacity of an additional adjustable final stage feed water heater, a high-pressure cylinder structure and the like, the configuration of a boiler system (relates to the configuration of a boiler economizer, the condition of a boiler heating surface, the configuration of a boiler flue gas waste heat recycling system and the like), the additional adjustable final stage steam extraction pressure value under different loads of sliding pressure operation and the additional adjustable final stage steam extraction pressure corresponding to the most economic feed water temperature value can be compared on the basis of ensuring that the economizer system does not generate boiling operation under different loads, and the optimal value (the most economic feed water temperature value is selected, on the one hand, the average heat absorption temperature is increased, the thermal cycle efficiency of the unit is increased, the steam extraction amount of a steam turbine is correspondingly increased, the cold source loss is reduced, and the economy of the unit is improved, and on the other hand, the boiler flue gas temperature is increased due to the relative increase of the feed water temperature, and the economic efficiency of the unit is reduced to a certain extent.

The invention provides an adjustable water supply regenerative system and a control method thereof, which are characterized by comprising the following steps: the control method is suitable for the configuration systems of different adjustable water supply heat recovery systems, the China patent with the application number of CN201110459533.2 provides an adjustable water supply heat recovery system with basic configuration, the China patent with the application number of CN201420700957.2 is provided with a corresponding high-addition water supply bypass on the basis of the adjustable water supply heat recovery system, in fact, on the basis of the China patent with the application number of CN201110459533.2, a plurality of different configuration systems can be derived according to different configurations of a steam side and a water side, and the control method is not only suitable for the different configuration systems, but also is not limited to maintaining the water supply temperature under different loads to be basically unchanged, so that the safe operation, the environmental protection performance and the economical efficiency of the equipment can be taken into consideration.

The invention provides an adjustable water supply heat recovery system, which is characterized by comprising

A high pressure cylinder of the steam turbine;

The additional adjustable final stage steam extraction port on the high pressure cylinder has higher steam extraction pressure than the conventional non-adjustable final stage steam extraction pressure of the high pressure cylinder (the sorting is carried out according to the flow direction of condensate water and water supply medium, which is equivalent to the final stage steam extraction which is not regulated on the traditional unit);

An additional adjustable final stage feedwater heater taking the additional adjustable final stage steam extraction of the high-pressure cylinder as a heat source;

the additional adjustable post-final stage steam extraction pipeline is connected with the additional adjustable post-final stage steam extraction port and the additional adjustable post-final stage feed water heater;

the adjustable steam extraction regulating valve is arranged on the additional adjustable final stage steam extraction pipeline and is used for regulating the steam extraction of the additional adjustable final stage steam extraction pipeline so as to control the steam extraction pressure behind the adjustable steam extraction regulating valve to control the outlet temperature of the additional adjustable final stage feed water heater to meet the required final feed water temperature;

Further characterized by further comprising at least one steam cooler, wherein the water side of at least one of said steam coolers is connected in series with the water side inlet or outlet of said additional adjustable post-final stage feedwater heater.

Optionally, the water side cooling device is characterized by further comprising at least one steam cooler, wherein the water side of at least one steam cooler is connected with the water side inlet or outlet of the additional adjustable final stage feedwater heater in parallel.

Further characterized by further comprising at least one water side regulating valve, wherein at least one of said water side regulating valves is connected in parallel with said additional adjustable post-final stage feedwater heater and in series with at least one of said steam coolers.

Optionally, the steam cooler further comprises at least one water side regulating valve, wherein at least one water side regulating valve is connected in series with the additional adjustable final stage feedwater heater and is connected in parallel with at least one steam cooler.

Optionally, the water side regulating valve is characterized by further comprising at least one water side regulating valve, wherein at least one water side regulating valve is connected with at least one steam cooler in series and is connected with an additional adjustable final stage feed water heater in parallel.

It should be noted that, the adjustable feedwater backheating system of the invention has a plurality of arrangement and combination modes in series or in parallel among different numbers of steam coolers, different numbers of water side regulating valves and additional adjustable final stage feedwater heaters. Any of the different arrangements based on the above-described devices should be within the scope of protection defined by the claims.

The control method of the adjustable water supply regenerative system provided by the invention comprises the following steps:

(a) According to the configuration of the boiler system (including the configuration conditions of the economizer system, the air preheater system, the boiler flue gas waste heat recovery system and the denitration catalyst system), on the basis of ensuring that the economizer system does not generate boiling operation under different loads and meets the operation of the denitration system, the most economic water supply temperature value under different loads is set, and the most economic water supply temperature value under different loads is converted and corresponds to the additional adjustable final stage steam extraction pressure value according to the configuration of the water supply side system (including the configuration conditions of the steam cooler, the additional adjustable final stage water supply heater water side bypass and the water side system connection condition).

(B) And selecting a reasonable additional adjustable final stage steam extraction port to obtain additional adjustable final stage steam extraction pressure values under different loads of sliding pressure operation.

(C) Comparing the additional adjustable final stage steam extraction pressure values under different loads of the steps (a) and (b), and if the additional adjustable final stage steam extraction pressure value of the step (a) is larger than the additional adjustable final stage steam extraction pressure value of the step (b) under the same load, feeding back the additional adjustable final stage steam extraction pressure value of the step (b) to an additional adjustable final stage steam extraction regulating valve to serve as a control target of the additional adjustable final stage steam extraction regulating valve; under the same load, if the additional adjustable final stage steam extraction pressure value of the step (a) is smaller than the additional adjustable final stage steam extraction pressure value of the step (b), feeding back the additional adjustable final stage steam extraction pressure value of the step (a) to an additional adjustable final stage steam extraction regulating valve to serve as a control target of the additional adjustable final stage steam extraction regulating valve; under the same load, if the additional adjustable final stage steam extraction pressure value of the step (a) is equal to the additional adjustable final stage steam extraction pressure value of the step (b), the additional adjustable final stage steam extraction pressure value of the step (a) or the step (b) is fed back to the additional adjustable final stage steam extraction regulating valve to serve as a control target of the additional adjustable final stage steam extraction regulating valve.

Accordingly, the control method of the adjustable feedwater backheating system according to the present invention is also within the scope of protection defined by the claims.

The conception, specific structure, and technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, features, and effects of the present invention.

Drawings

Fig. 1 is a schematic structural view of a first embodiment of the present invention.

FIG. 2 is a graph comparing control methods according to a first embodiment of the present invention.

Fig. 3 and fig. 4 are graphs showing the control method according to the first embodiment of the present invention.

Fig. 5 is a schematic structural view of a second embodiment of the present invention.

Fig. 6 is a schematic structural view of a third embodiment of the present invention.

Fig. 7 is a schematic structural view of a fourth embodiment of the present invention.

Fig. 8 is a schematic structural view of a fifth embodiment of the present invention.

Fig. 9 is a schematic structural view of a sixth embodiment of the present invention.

Fig. 10 is a schematic structural view of a seventh embodiment of the present invention.

Fig. 11 is a schematic structural view of an eighth embodiment of the present invention.

Fig. 12 is a schematic structural view of a ninth embodiment of the present invention.

Fig. 13 is a schematic structural view of a tenth embodiment of the present invention.

Fig. 14 is a schematic structural view of an eleventh embodiment of the present invention.

Fig. 15 is a schematic structural view of a twelfth embodiment of the present invention.

Fig. 16 is a schematic structural view of a thirteenth embodiment of the present invention.

Fig. 17 is a schematic structural view of a fourteenth embodiment of the present invention.

Fig. 18 is a schematic structural view of a fifteenth embodiment of the present invention.

Fig. 19 is a schematic structural view of a sixteenth embodiment of the present invention.

Fig. 20 is a schematic structural view of a seventeenth embodiment of the present invention.

Fig. 21 is a schematic structural view of an eighteenth embodiment of the present invention.

Fig. 22 is a schematic structural view of a nineteenth embodiment of the present invention.

Fig. 23 is a schematic structural view of a twentieth embodiment of the present invention.

Fig. 24 is a schematic structural view of a twenty-first embodiment of the invention.

Fig. 25 is a schematic structural view of a twenty-second embodiment of the invention.

Fig. 26 is a schematic structural view of a twenty-third embodiment of the invention.

Fig. 27 is a schematic structural view of a twenty-fourth embodiment of the invention.

Fig. 28 is a schematic structural view of a twenty-fifth embodiment of the invention.

Fig. 29 is a schematic structural view of a twenty-sixth embodiment of the invention.

Fig. 30 is a schematic structural view of a twenty-seventh embodiment of the invention.

Fig. 31 is a schematic structural view of a twenty-eighth embodiment of the invention.

Fig. 32 is a schematic structural view of a twenty-ninth embodiment of the invention.

Fig. 33 is a schematic structural view of a thirty-third embodiment of the present invention.

Fig. 34 is a schematic structural view of a thirty-first embodiment of the present invention.

Fig. 35 is a schematic structural view of a thirty-second embodiment of the present invention.

Fig. 36 is a schematic structural view of a thirty-third embodiment of the present invention.

Fig. 37 is a schematic structural view of a thirty-fourth embodiment of the present invention.

Fig. 38 is a schematic structural view of a thirty-fifth embodiment of the present invention.

Fig. 39 is a schematic structural view of a thirty-sixth embodiment of the present invention.

Fig. 40 is a schematic structural view of a thirty-seventh embodiment of the present invention.

Fig. 41 is a schematic structural view of a thirty-eighth embodiment of the present invention.

Fig. 42 is a schematic structural view of a thirty-ninth embodiment of the present invention.

Fig. 43 is a schematic structural view of a fortieth embodiment of the present invention.

Fig. 44 is a schematic structural view of a forty-first embodiment of the present invention.

Fig. 45 is a schematic structural view of a forty-second embodiment of the present invention.

Wherein, 0-adding the adjustable last stage steam extraction port; 1-a conventional final stage steam extraction port; 3-other conventional systems; 4-steam inlet of a high-pressure cylinder; 5-a high-pressure cylinder; 6-final water supply; 7-a water side regulating valve; 10-a conventional final stage steam extraction pipeline; 11-conventional final stage feedwater heater; 00-an additional adjustable post-final stage steam extraction pipeline; 00' -extraction pipe, 01-additional adjustable final stage feed water heater; 02-adding an adjustable last stage steam extraction regulating valve; 20-steam inlet of a steam cooler; 21-steam cooler.

Detailed description of the preferred embodiments

Fig. 1 shows a first embodiment of the present invention, in which an additional adjustable post-final stage steam extraction port 0, an additional adjustable post-final stage steam extraction pipe 00, and an additional adjustable post-final stage feedwater heater 01 on a high-pressure cylinder 5 are added on the basis of a conventional post-final stage steam extraction port 1, a final stage steam extraction port 10, and a final stage feedwater heater 11, and the additional adjustable post-final stage feedwater heater 01 is connected with the additional adjustable post-final stage steam extraction port 0 on the high-pressure cylinder 5 through the additional adjustable post-final stage steam extraction pipe 00 and is connected in series with the conventional post-stage feedwater heater 11. An additional adjustable post-final stage steam extraction regulating valve 02 is arranged on the additional adjustable post-final stage steam extraction pipeline 00 and is used for regulating the steam extraction of the additional adjustable post-final stage steam extraction pipeline 00, the water supply temperature of the outlet of the additional adjustable post-final stage feed water heater 01 is controlled by controlling the pressure behind the additional adjustable post-final stage steam extraction regulating valve 02, the water supply of the outlet of the additional adjustable post-final stage feed water heater 01 is further heated by the steam extraction 20 through a steam cooler 21, and the heat source of the steam cooler 21 is other conventional high Wen Chouqi.

The control method of the invention is described in detail by an example of a 1000MW unit of a certain power plant, wherein the steam turbine is an ultra-supercritical single-shaft, single-reheat, four-cylinder and four-exhaust condensing steam turbine.

Firstly, the factors that the boiler economizer is configured in a non-boiling way, the air preheater area is still configured in a traditional design, the recycling degree of a flue gas waste heat recycling system is relatively low, the temperature requirement of a denitration catalyst is low and the like are considered. According to the calculation, the most economical feedwater temperature value of the unit under different loads can be determined, meanwhile, considering the feedwater side system, the steam cooler is connected in series with the additional adjustable post-final stage feedwater heater, and according to the feedwater flow direction, the steam cooler is arranged behind the additional adjustable post-final stage feedwater heater, so that after the temperature rise of the steam cooler 21 is subtracted from the most economical feedwater temperature value under different loads, the upper end difference of the additional adjustable post-final stage feedwater heater 01 is added, and the saturated pressure value corresponding to the temperature value is the additional adjustable post-final stage extraction pressure value.

And secondly, according to the structure of the high-pressure cylinder, the running load of the unit is frequently located, and the like, the specific position of the additional adjustable final stage steam extraction port is optimally selected, so that the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure running of the additional adjustable final stage steam extraction port under different loads can be obtained.

The control strategy of the additional adjustable post-final stage steam extraction regulating valve can be determined by comparing the additional adjustable post-final stage steam extraction pressure value corresponding to the most economical water supply temperature value conversion under the same load with the additional adjustable post-final stage steam extraction pressure value corresponding to the sliding pressure operation of the additional adjustable post-final stage steam extraction port. When the additional adjustable post-final stage steam extraction pressure value corresponding to the most economic water supply temperature value conversion is smaller than the additional adjustable post-final stage steam extraction pressure value corresponding to the sliding pressure operation of the additional adjustable post-final stage steam extraction port under the same load, the additional adjustable post-final stage steam extraction pressure value corresponding to the most economic water supply temperature value conversion under the load is used as a control target of the additional adjustable post-final stage steam extraction regulating valve; when the additional adjustable final stage steam extraction pressure value corresponding to the most economical water supply temperature value conversion is larger than the additional adjustable final stage steam extraction pressure value corresponding to the final stage steam extraction port sliding pressure operation under the same load, the additional adjustable final stage steam extraction pressure value corresponding to the additional adjustable final stage steam extraction port sliding pressure operation under the load is used as a control target of the additional adjustable final stage steam extraction regulating valve.

For example, when the extraction pressures of the additional adjustable final stage extraction ports selected in an optimized manner under the rated working condition (1000 WM) of the unit are 15.05MPa (extraction port a) and 9.76 MPa (extraction port b), respectively, the final stage extraction pressures corresponding to the most economical water supply temperatures under different loads, and the final stage extraction pressures corresponding to the sliding operation of the final stage extraction ports under different loads of the extraction ports a and b are shown in fig. 2. The control targets of the additional adjustable final stage steam extraction regulating valve for the steam extraction port a are shown in figure 3 according to the control strategy of the additional adjustable final stage steam extraction regulating valve by comparing the final stage steam extraction pressure value corresponding to the conversion of the most economical water supply temperature value under the same load with the final stage steam extraction pressure value corresponding to the sliding pressure operation of the final stage steam extraction port; for the steam extraction port b, the control target of the additional adjustable final stage steam extraction regulating valve is shown in fig. 4. When other additional adjustable final stage steam extraction ports are optimally selected, the control targets of the additional adjustable final stage steam extraction regulating valves can be determined according to the above, and the detailed description is omitted here.

Detailed description of the preferred embodiments

Fig. 5 shows a second embodiment of the present invention, which is different from the first embodiment in terms of the system structural arrangement, in which the steam cooler 21 is arranged at the inlet of the additional adjustable final stage feedwater heater 01, that is, the feedwater is heated in the conventional final stage feedwater heater 11, then heated by the steam cooler 21, and then heated to the additional adjustable final stage feedwater heater 01. Since the outlet feedwater temperature of the additional adjustable final stage feedwater heater 01 is the final feedwater temperature, the control method differs from the first embodiment in that the sum of the most economical feedwater temperature value and the upper end difference of the additional adjustable final stage feedwater heater is the saturation pressure value corresponding to the sum of the most economical feedwater temperature value and the upper end difference of the additional adjustable final stage feedwater heater. Similarly, the other steps are the same as those in the first embodiment, namely, the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure operation of the additional adjustable final stage steam extraction port under different loads is obtained, and the additional adjustable final stage steam extraction pressure value are compared to finally obtain the control target of the additional adjustable final stage steam extraction regulating valve 02, which is not described herein again.

It should be noted that, in this embodiment, the steam cooler 21 is actually used to utilize the superheat degree of the other conventional high Wen Chouqi, and then further heat the feedwater, and in fact, the arrangement may be omitted, and if there is no steam cooler 21, only the inlet temperature of the additional adjustable final stage feedwater heater 01 is changed, and the control strategy of the whole system is still unchanged.

Detailed description of the preferred embodiments

Fig. 6 is a third embodiment of the present invention, which is relatively close to the second embodiment, and is compared with the first embodiment, and the difference in system structural arrangement is: the additional adjustable final-stage feedwater heater 01 of the embodiment is provided with a water side bypass, and the water side bypass is at least provided with a water side regulating valve 7, and of course, the water side regulating valve can be provided with an isolation valve before and after so as to facilitate the on-line maintenance of the isolation regulating valve. The additional adjustable final stage feedwater heater 01 can be set to a partial capacity due to the addition of the water side bypass. On the one hand, the difficulty in the manufacturing process of the high-parameter full-capacity feedwater heater is avoided. In another aspect, the cost of the feedwater heater is reduced.

The difference between the control method of this embodiment and the control method of the second embodiment is that the most economical feedwater temperature value corresponds to the feedwater temperature mixture value of the additional adjustable final stage feedwater heater 01 and the outlet of the water side regulating valve 7. Since the part of the feedwater flowing through the water side bypass is not heated by the additional adjustable post-stage feedwater heater 01, the feedwater temperature of the water side bypass is actually equivalent to the feedwater temperature of the inlet of the additional adjustable post-stage feedwater heater 01, and the feedwater flow which is split into the additional adjustable post-stage feedwater heater can be controlled by controlling the bypass water side regulating valve 7, so that the feedwater temperature mixture value of the additional adjustable post-stage feedwater heater 01 and the outlet of the water side regulating valve 7 can be finally controlled by jointly controlling the additional adjustable post-stage extraction regulating valve 02 and the water side regulating valve 7.

Therefore, the control strategy of the present embodiment is:

Firstly, determining the most economical water supply temperature value of the unit under different loads according to the conditions of boiler system configuration and the like, secondly, determining the additional adjustable final stage steam extraction ports which are optimally selected according to the running load and the like of a high-pressure cylinder structure of a steam turbine where the unit is frequently located, and further determining the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure running of the additional adjustable final stage steam extraction ports with different loads. Thereby determining the adjustable range of the additional adjustable final stage steam extraction adjusting valve.

And taking the most economic water supply temperature value under different loads as the combined control target of the additional adjustable final stage steam extraction regulating valve and the water side regulating valve.

In the combined control process of the two regulating valves, on the premise that the most economical water supply temperature value can be met, the opening of the additional adjustable last-stage steam extraction regulating valve 02 is used as a first regulating action, namely the additional adjustable last-stage steam extraction regulating valve 02 is opened to reduce steam extraction throttling loss, and the water side regulating valve 7 is used as a second regulating action to be matched for regulation until the regulation reaches a control target.

Detailed description of the preferred embodiments

Fig. 7 is a fourth embodiment of the present invention, which is relatively close to the embodiments, and compares the two embodiments, and the main differences in system structural arrangement are: in this embodiment, the steam cooler 21 is disposed after the additional adjustable final stage heater 01 with the water side bypass and water side regulating valve 7 (according to the water supply flow direction), and at this time, after subtracting the temperature rise of the steam cooler 21 from the most economical water supply temperature value, the water supply temperature mixing value of the additional adjustable final stage water heater 01 and the outlet of the bypass water side regulating valve 7 corresponds. Therefore, the main difference between the control method of the present embodiment and the third embodiment is that the most economical feedwater temperature value under different loads needs to be subtracted from the temperature rise of the steam cooler 21, and then the temperature rise is used as the combined control target of the additional adjustable final stage extraction steam regulating valve 02 and the water side regulating valve 7.

The control strategy of this embodiment is:

Firstly, determining the most economical water supply temperature value of the unit under different loads according to the conditions of boiler system configuration and the like, secondly, determining the additional adjustable final stage steam extraction ports which are optimally selected according to the running load and the like of a high-pressure cylinder structure of a steam turbine where the unit is frequently located, and further determining the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure running of the additional adjustable final stage steam extraction ports with different loads. Thereby determining the adjustable range of the extraction regulating valve.

After the temperature rise of the steam cooler 21 is deducted from the most economical water supply temperature value under different loads, the temperature rise is used as a combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7.

Detailed description of the preferred embodiments

Fig. 8 shows a fifth embodiment of the present invention, in which an additional adjustable post-final stage steam extraction port 0, an additional adjustable post-final stage steam extraction pipe 00 and an additional adjustable post-final stage feedwater heater 01 on a high-pressure cylinder 5 are added on the basis of a conventional post-final stage steam extraction port 1, a post-final stage steam extraction port 10 and a post-final stage feedwater heater 11, the additional adjustable post-final stage feedwater heater 01 is connected with the additional adjustable post-final stage steam extraction port 0 on the high-pressure cylinder 5 through the additional adjustable post-final stage steam extraction pipe 00, an additional adjustable post-final stage steam extraction regulating valve 02 is arranged on the additional adjustable post-final stage steam extraction pipe 00 for regulating the steam extraction of the additional adjustable post-final stage steam extraction pipe 00, the water supply temperature of the outlet of the additional adjustable post-final stage feedwater heater 01 is controlled by controlling the pressure behind the additional adjustable post-final stage steam extraction regulating valve 02, and a regulating valve 7 is arranged on a water side pipe of the additional adjustable post-final stage feedwater heater 01, connected in parallel with a steam cooler 21 and connected in series with the conventional post-stage feedwater heater 11. The feed water at the outlet of the final stage feed water heater 11 is split into two parts, one part is heated by the additional adjustable final stage feed water heater 01, the other part is heated by the steam cooler 21, and then the two parts are mixed and enter the boiler economizer as final feed water. The additional adjustable final stage feedwater heater 01 is provided with a regulating valve 7 which can be used for controlling and regulating the flow of the feedwater which is split into the additional adjustable final stage feedwater heater 01 and the steam cooler 21, thereby controlling the final feedwater temperature after mixing. It should be noted that the regulating valve may also be installed at one end of the steam cooler 21, and has the same main function, and is also used for controlling and regulating the water supply flow of the split flow into the additional adjustable final stage feedwater heater 01 and the steam cooler 21. Of course, an isolation valve can be additionally arranged on the steam cooler 21 or the side of the additional adjustable final-stage feedwater heater for isolation, so that an isolated system is convenient to overhaul online.

The difference from the first embodiment is that the steam cooler 21 is not connected in series but in parallel with the additional adjustable final feedwater heater 01 in the system configuration. Since the final feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 mixes with the outlet of the steam cooler 21. In this embodiment, the main difference between the control method and the first embodiment is that the most economical feedwater temperature is the result of the joint adjustment of the additional adjustable final stage steam extraction control valve 02 and the water side control valve 7. The water supply temperature of the outlet of the additional adjustable final stage water supply heater 01 can be controlled by controlling the additional adjustable final stage steam extraction regulating valve 02; by controlling the water side regulating valve 7, the water supply flow entering the additional adjustable final stage feed water heater 01 can be controlled, and by controlling the two regulating valves in combination, the water supply temperature of the mixture of the outlet of the additional adjustable final stage feed water heater 01 and the outlet of the steam cooler 21 can be controlled.

Therefore, the control strategy of the present embodiment is:

Firstly, determining the most economical water supply temperature value of the unit under different loads according to the conditions of boiler system configuration and the like, secondly, determining the additional adjustable final stage steam extraction ports which are optimally selected according to the running load and the like of a high-pressure cylinder structure of a steam turbine where the unit is frequently located, and further determining the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure running of the additional adjustable final stage steam extraction ports with different loads. Thereby determining the adjustable pressure range of the additional adjustable final stage extraction regulating valve 02.

Meanwhile, in order to avoid that the difference between the water supply temperature value at the outlet of the final-stage feed water heater 01 and the water supply temperature value at the outlet of the steam cooler 21 is too large, which is not beneficial to the safety of a pipeline system, a maximum difference can be manually set and used as a feedback factor of the water side regulating valve 7 and the additional adjustable final-stage steam extraction regulating valve 02, and once the safety difference is exceeded, the two regulating valves can be jointly regulated to control the difference to be within a safety range.

Detailed description of the preferred embodiments six

Fig. 9 shows a sixth embodiment of the present invention, which is different from the first embodiment in that a steam cooler 03 and a steam extraction pipeline 00 'are added in the structural arrangement of the system, the additional adjustable final stage steam extraction firstly enters the steam cooler 03 through the additional adjustable final stage steam extraction pipeline 00 and the additional adjustable final stage steam extraction regulating valve 02 in sequence to heat water, then enters the additional adjustable final stage feedwater heater 01 through the steam extraction pipeline 00', the steam cooler 03 is arranged in series between the steam cooler 21 and the additional adjustable final stage feedwater heater 01, and the water is heated by the additional adjustable final stage feedwater heater 01 after being heated by the conventional final stage feedwater heater 11, then is heated by the steam cooler 03, and then is heated by the steam cooler 21. Therefore, after the most economical feedwater temperature values under different loads are subtracted by the temperature rise of the steam cooler 21 and the steam cooler 03, the upper end difference of the additional adjustable final stage feedwater heater 01 is added, and the saturated pressure value corresponding to the temperature value is the additional adjustable final stage extraction pressure value. Similarly, the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure operation of the additional adjustable final stage steam extraction port under different loads can be obtained, then the additional adjustable final stage steam extraction pressure value and the additional adjustable final stage steam extraction pressure value are compared, and finally the control target of the additional adjustable final stage steam extraction regulating valve 02 is obtained, and the other control modes are the same as those of the first embodiment, and are not repeated here.

Detailed description of the preferred embodiments

Fig. 10 shows a seventh embodiment of the present invention, which is different from the sixth embodiment in terms of system structural arrangement, in which the steam cooler 21 is arranged in series between the steam cooler 03 and the additional adjustable final stage feedwater heater 01, and the feedwater is heated in the conventional final stage feedwater heater 11, then heated in the additional adjustable final stage feedwater heater 01, then heated in the steam cooler 21, and then heated in the steam cooler 03. Similarly, after subtracting the temperature rise of the steam cooler 03 and the steam cooler 21 from the most economical feedwater temperature value under different loads, the upper end difference of the additional adjustable final stage feedwater heater 01 is added, and the saturated pressure value corresponding to the temperature value is the additional adjustable final stage extraction pressure value. Similarly, the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure operation of the additional adjustable final stage steam extraction port under different loads can be obtained, the additional adjustable final stage steam extraction pressure value and the additional adjustable final stage steam extraction pressure value are compared, and finally the control target of the additional adjustable final stage steam extraction regulating valve 02 is obtained, and the other control modes are the same as those of the first embodiment, and are not repeated here.

Detailed description of the preferred embodiments

Fig. 11 shows an eighth embodiment of the present invention, which is different from the sixth embodiment in terms of system structural arrangement, in which the additional adjustable final-stage feedwater heater 01 is arranged in series between the steam cooler 21 and the steam cooler 03, and the feedwater is heated in the conventional final-stage feedwater heater 11, then heated in the steam cooler 03, then heated in the additional adjustable final-stage feedwater heater 01, and then heated in the steam cooler 21. Therefore, after the most economical feedwater temperature value under different loads is subtracted from the temperature rise of the steam cooler 21, the upper end difference of the additional adjustable final stage feedwater heater 01 is added, and the saturation pressure value corresponding to the temperature value is the additional adjustable final stage steam extraction pressure value. Similarly, the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure operation of the additional adjustable final stage steam extraction port under different loads can be obtained, the additional adjustable final stage steam extraction pressure value and the additional adjustable final stage steam extraction pressure value are compared, and finally the control target of the additional adjustable final stage steam extraction regulating valve 02 is obtained, and the other control modes are the same as those of the first embodiment, and are not repeated here.

Detailed description of the preferred embodiments nine

Fig. 12 shows a ninth embodiment of the present invention, which is different from the eighth embodiment in terms of system structural arrangement, in which the additional adjustable final-stage feedwater heater 01 is arranged in series between the steam cooler 03 and the steam cooler 21, and the feedwater is heated in the conventional final-stage feedwater heater 11, then heated in the steam cooler 21, then heated in the additional adjustable final-stage feedwater heater 01, and then heated in the steam cooler 03. Therefore, after the most economical feedwater temperature value under different loads is subtracted from the temperature rise of the steam cooler 03, the upper end difference of the additional adjustable final stage feedwater heater 01 is added, and the saturated pressure value corresponding to the temperature value is the additional adjustable final stage steam extraction pressure value. Similarly, the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure operation of the additional adjustable final stage steam extraction port under different loads can be obtained, the additional adjustable final stage steam extraction pressure value and the additional adjustable final stage steam extraction pressure value are compared, and finally the control target of the additional adjustable final stage steam extraction regulating valve 02 is obtained, and the other control modes are the same as those of the first embodiment, and are not repeated here.

Detailed description of the preferred embodiments

Fig. 13 shows a tenth embodiment of the present invention, which differs from the eighth embodiment in that the steam cooler 21 is arranged in series between the additional adjustable final stage feedwater heater 01 and the steam cooler 03, and the feedwater is heated in the conventional final stage feedwater heater 11, then heated in the steam cooler 03, then heated in the steam cooler 21, and then heated in the additional adjustable final stage feedwater heater 01. Therefore, the most economical feedwater temperature value under different loads is added with the upper end difference of the additional adjustable final stage feedwater heater 01, and the saturated pressure value corresponding to the temperature value is the additional adjustable final stage extraction pressure value. Similarly, the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure operation of the additional adjustable final stage steam extraction port under different loads can be obtained, the additional adjustable final stage steam extraction pressure value and the additional adjustable final stage steam extraction pressure value are compared, and finally the control target of the additional adjustable final stage steam extraction regulating valve 02 is obtained, and the other control modes are the same as those of the first embodiment, and are not repeated here.

Detailed description of the invention eleven

Fig. 14 shows an eleventh embodiment of the present invention, which is different from the tenth embodiment in terms of system configuration, in which the steam cooler 03 is disposed in series between the additional adjustable final-stage feedwater heater 01 and the steam cooler 21, and the feedwater is heated in the conventional final-stage feedwater heater 11, then heated by the steam cooler 21, then heated by the steam cooler 03, and then heated by the additional adjustable final-stage feedwater heater 01. Therefore, the most economical feedwater temperature value under different loads is added with the upper end difference of the additional adjustable final stage feedwater heater 01, and the saturated pressure value corresponding to the temperature value is the additional adjustable final stage extraction pressure value. Similarly, the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure operation of the additional adjustable final stage steam extraction port under different loads can be obtained, the additional adjustable final stage steam extraction pressure value and the additional adjustable final stage steam extraction pressure value are compared, and finally the control target of the additional adjustable final stage steam extraction regulating valve 02 is obtained, and the other control modes are the same as those of the first embodiment, and are not repeated here.

Detailed description of the invention twelve

Fig. 15 is a difference between the twelfth embodiment and the sixth embodiment of the present invention, in terms of the system structural arrangement, the additional adjustable final-stage feedwater heater 01 of the present embodiment is provided with a water side bypass, and at least a water side regulating valve 7 is provided on the water side bypass, and of course, isolation valves may be arranged before and after the water side regulating valve, so as to facilitate on-line maintenance of the isolation regulating valve. The additional adjustable final stage feedwater heater 01 can be set to a partial capacity due to the addition of the water side bypass. On the one hand, the difficulty in the manufacturing process of the high-parameter full-capacity feedwater heater is avoided. In another aspect, the cost of the feedwater heater is reduced.

At this time, the inlet feed water temperature of the steam cooler 03 is a feed water temperature mixture value of the additional adjustable final stage feed water heater 01 and the outlet of the water side regulating valve 7. Therefore, the water side bypass water supply temperature is actually equivalent to the water supply temperature of the inlet of the additional adjustable final stage water heater 01, and the water supply flow of the additional adjustable final stage water heater can be controlled by controlling the bypass water side regulating valve 7, so that the water supply temperature mixing value of the additional adjustable final stage water heater 01 and the outlet of the water side regulating valve 7 can be controlled by jointly controlling the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7.

At this time, the most economical feedwater temperature values under different loads are subtracted by the temperature rise of the steam cooler 21 and the steam cooler 03, and then the feedwater temperature mixture value of the additional adjustable final stage feedwater heater 01 and the outlet of the water side regulating valve 7 is obtained.

Therefore, the control strategy of the present embodiment is:

The value obtained by subtracting the temperature rise of the steam cooler 21 and the steam cooler 03 from the most economical water supply temperature value under different loads is used as the combined control target of the additional adjustable final stage steam extraction regulating valve and the water side regulating valve.

Detailed description of the invention thirteen

Fig. 16 shows a thirteenth embodiment of the present invention, which is different from the twelfth embodiment in terms of system configuration, in which the steam cooler 21 is arranged in series between the additional adjustable final-stage feedwater heater 01 and its bypass and the steam cooler 03, and the feedwater is heated in the conventional final-stage feedwater heater 11, then heated in the additional adjustable final-stage feedwater heater 01 and its bypass, then heated in the steam cooler 21, and then heated in the steam cooler 03. Therefore, after subtracting the temperature rise of the steam cooler 03 and the steam cooler 21 from the most economical feedwater temperature value under different loads, the feedwater temperature mixture value of the additional adjustable final stage feedwater heater 01 and the outlet of the water side regulating valve 7 is obtained. At this time, the most economical feedwater temperature value under different loads is subtracted from the temperature rise value of the steam cooler 21 and the steam cooler 03 to serve as the combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the twelve embodiments, and are not repeated here.

Detailed description of the invention fourteen

Fig. 17 shows a fourteenth embodiment of the present invention, which is different from the twelfth embodiment in terms of system configuration, in which the additional adjustable final-stage feedwater heater 01 and its bypass are arranged in series between the steam cooler 21 and the steam cooler 03, and the feedwater is heated in the conventional final-stage feedwater heater 11, then heated in the steam cooler 03, then heated in the additional adjustable final-stage feedwater heater 01 and its bypass, and then heated in the steam cooler 21. Therefore, after subtracting the temperature rise of the steam cooler 21 from the most economical feedwater temperature value under different loads, the feedwater temperature mixture value of the additional adjustable final stage feedwater heater 01 and the outlet of the water side regulating valve 7 is obtained. At this time, the value obtained by subtracting the temperature rise of the steam cooler 21 from the most economical feedwater temperature value under different loads is used as the combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes and embodiments are the same and are not repeated here.

Description of the preferred embodiments fifteen

Fig. 18 shows a fifteenth embodiment of the present invention, which is different from the fourteenth embodiment in terms of system configuration, in which the additional adjustable final-stage feedwater heater 01 and its bypass are arranged in series between the steam cooler 03 and the steam cooler 21, and the feedwater is heated in the conventional final-stage feedwater heater 11, then heated in the steam cooler 21, then heated in the additional adjustable final-stage feedwater heater 01 and its bypass, and then heated in the steam cooler 03. Therefore, after subtracting the temperature rise of the steam cooler 03 from the most economical feedwater temperature value under different loads, the feedwater temperature mixture value of the additional adjustable final stage feedwater heater 01 and the outlet of the water side regulating valve 7 is obtained. At this time, the value obtained by subtracting the temperature rise of the steam cooler 03 from the most economical feedwater temperature value under different loads is used as the combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes and embodiments are the same and are not repeated here.

Description of the invention sixteen

Fig. 19 shows a sixteenth embodiment of the present invention, which is different from the fourteenth embodiment in terms of system configuration, in which the additional adjustable final-stage feedwater heater 01 and its bypass are arranged in series between the steam cooler 21 and the steam cooler 03, and the feedwater is heated in the conventional final-stage feedwater heater 11, then heated in the steam cooler 03, then heated in the additional adjustable final-stage feedwater heater 01 and its bypass, and then heated in the steam cooler 21. Therefore, after subtracting the temperature rise of the steam cooler 21 from the most economical feedwater temperature value under different loads, the feedwater temperature mixture value of the additional adjustable final stage feedwater heater 01 and the outlet of the water side regulating valve 7 is obtained. At this time, the value obtained by subtracting the temperature rise of the steam cooler 21 from the most economical feedwater temperature value under different loads is used as the combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes and embodiments are the same and are not repeated here.

Seventeenth embodiment of the invention

Fig. 20 shows a seventeenth embodiment of the present invention, which is different from the sixteenth embodiment in terms of system configuration, in which the steam cooler 21 is arranged in series between the additional adjustable final-stage feedwater heater 01 and its bypass and the steam cooler 03, and the feedwater is heated in the conventional final-stage feedwater heater 11, then heated by the steam cooler 03, then heated by the steam cooler 21, and then further heated by the additional adjustable final-stage feedwater heater 01 and its bypass. Therefore, the most economical water supply temperature value under different loads is the water supply temperature mixed value of the additional adjustable final stage water supply heater 01 and the outlet of the water side regulating valve 7. At this time, the most economical water supply temperature value under different loads is used as the combined control target of the additional adjustable post-final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the embodiment twelve, and are not repeated here.

Detailed description of the invention eighteen

Fig. 21 shows an eighteenth embodiment of the present invention, which is different from the sixteenth embodiment in terms of system configuration, in which the steam cooler 03 is arranged in series between the additional adjustable final-stage feedwater heater 01 and its bypass and the steam cooler 21, and the feedwater is heated in the conventional final-stage feedwater heater 11, then heated by the steam cooler 21, then heated by the steam cooler 03, and then further heated by the additional adjustable final-stage feedwater heater 01 and its bypass. Therefore, the most economical water supply temperature value under different loads is the water supply temperature mixed value of the additional adjustable final stage water supply heater 01 and the outlet of the water side regulating valve 7. At this time, the most economical water supply temperature value under different loads is used as the combined control target of the additional adjustable post-final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the embodiment twelve, and are not repeated here.

Detailed description of the invention nineteenth embodiment

Fig. 22 shows a nineteenth embodiment of the present invention, in which an additional adjustable final stage steam extraction port 0, an additional adjustable final stage steam extraction pipe 00, an additional adjustable final stage steam extraction regulating valve 02, a steam extraction pipe 00', a steam cooler 03 and an additional adjustable final stage feedwater heater 01 are added to a conventional final stage steam extraction port 1, final stage steam extraction 10 and final stage feedwater heater 11. The additional adjustable final stage steam extraction firstly sequentially enters the steam cooler 03 through the additional adjustable final stage steam extraction pipeline 00 and the additional adjustable final stage steam extraction regulating valve 02 to heat water supply, and then enters the additional adjustable final stage feed water heater 01 through the steam extraction pipeline 00' to heat water supply.

At the same time, a regulating valve 7 is arranged on the water-side line of the additional adjustable final stage feedwater heater 01, connected in parallel with the steam cooler 03, and connected in series with a conventional final stage feedwater heater 11. The additional adjustable final stage steam extraction regulating valve 02 is utilized to regulate the steam extraction of the additional adjustable final stage steam extraction pipeline 00, so as to control the pressure behind the additional adjustable final stage steam extraction regulating valve 02; the feed water at the outlet of the final stage feed water heater 11 is split into two parts, one part is heated by the additional adjustable final stage feed water heater 01, the other part is heated by the steam cooler 03, then the two parts are mixed, and the two parts are taken as final feed water to enter the steam cooler 21 for heating, and finally enter the boiler economizer. The additional adjustable final stage feed water heater 01 is provided with a regulating valve 7 which can be used for controlling and regulating the feed water flow which is split into the additional adjustable final stage feed water heater 01 and the steam cooler 03. Therefore, the temperature of the mixed feedwater of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 03 is controlled by jointly adjusting the additional adjustable final stage extraction adjusting valve 02 and the adjusting valve 7.

Of course, an isolation valve can be additionally arranged on the steam cooler 21 or the side of the additional adjustable final-stage feedwater heater for isolation, so that an isolated system is convenient to overhaul online.

In this embodiment, after the most economical feedwater temperature is subtracted from the temperature rise of the steam cooler 21, the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 is mixed with the outlet of the steam cooler 03 is the result of the joint adjustment of the additional adjustable final stage extraction steam regulating valve 02 and the water side regulating valve 7.

The steam extraction pressure entering the steam cooler 03 and the additional adjustable final stage feed water heater 01 can be controlled by controlling the additional adjustable final stage steam extraction regulating valve 02; by controlling the water side regulating valve 7, the water supply flow rate distributed into the steam cooler 03 and the additional adjustable final stage feed water heater 01 can be controlled, and by jointly controlling the two regulating valves, the water supply temperature of the mixture of the outlet of the additional adjustable final stage feed water heater 01 and the outlet of the steam cooler 03 can be controlled.

Therefore, the control strategy of the present embodiment is:

Firstly, according to the conditions of boiler system configuration and the like, the most economical water supply temperature value of the unit under different loads is determined, after the temperature rise of the steam cooler 21 is subtracted, according to the high-pressure cylinder structure of a steam turbine, the running load and the like where the unit is frequently located, the additional adjustable final stage steam extraction port which is optimally selected is determined, and then the additional adjustable final stage steam extraction pressure value corresponding to the sliding pressure running of the additional adjustable final stage steam extraction port under different loads is determined. Thereby determining the adjustable pressure range of the additional adjustable final stage extraction regulating valve 02.

The temperature value obtained by subtracting the temperature rise of the steam cooler 21 from the most economical water supply temperature value under different loads is used as the combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7.

Meanwhile, in order to avoid that the difference between the water supply temperature value at the outlet of the final-stage feed water heater 01 and the water supply temperature value at the outlet of the steam cooler 03 is too large, which is not beneficial to the safety of a pipeline system, a maximum difference value can be manually set and used as a feedback factor of the water side regulating valve 7 and the additional adjustable final-stage steam extraction regulating valve 02, and once the safety difference value is exceeded, the two regulating valves can be jointly regulated to control the difference value to be within a safety range.

Detailed description of the invention twenty

Fig. 23 shows a twentieth embodiment of the present invention, which differs from the nineteenth embodiment in that the system is configured such that a regulator valve 7 is provided in the water side pipe of the steam cooler 03, and is connected in parallel with the additional adjustable final stage feedwater heater 01, and is connected in series with the conventional final stage feedwater heater 11. The feed water is fed from the outlet of a conventional final-stage feed water heater 11, enters the steam cooler 03 and the additional adjustable final-stage feed water heater 01 respectively in two paths for heating, and enters the steam cooler 21 for heating after the two paths of feed water are mixed. In this embodiment, after the most economical feedwater temperature is subtracted from the temperature rise of the steam cooler 21, the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 is mixed with the outlet of the steam cooler 03 is the result of the joint adjustment of the additional adjustable final stage extraction steam regulating valve 02 and the water side regulating valve 7. At this time, the temperature value obtained by subtracting the temperature rise of the steam cooler 21 from the most economical feedwater temperature value under different loads is used as the combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the embodiment, and are not repeated here.

Detailed description of the invention twenty-one

Fig. 24 shows a twenty-first embodiment of the present invention, which differs from the nineteenth embodiment in that the system is configured such that a regulating valve 7 is provided in the water-side pipe of the additional adjustable final-stage feedwater heater 01, connected in parallel with the steam cooler 03, and connected in series with the steam cooler 21. The feed water is fed from the outlet of a conventional final-stage feed water heater 11, enters a steam cooler 21 for heating, and then enters a steam cooler 03 and an additional adjustable final-stage feed water heater 01 for heating respectively in two paths, and then enters a boiler economizer after being mixed. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 03 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Detailed description of the invention twenty-two

Fig. 25 shows a twenty-second embodiment of the present invention, which is different from the twenty-first embodiment in that the system is configured such that a regulating valve 7 is provided in a water side pipe of the steam cooler 03, is connected in parallel with the additional adjustable final stage feedwater heater 01, and is connected in series with the steam cooler 21. The feed water is fed from the outlet of a conventional final-stage feed water heater 11, enters a steam cooler 21 for heating, and then enters a steam cooler 03 and an additional adjustable final-stage feed water heater 01 for heating respectively in two paths, and then enters a boiler economizer after being mixed. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 03 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Detailed description of the invention twenty-three

Fig. 26 shows a twenty-third embodiment of the present invention, which differs from the twenty-first embodiment in that the system is configured such that the regulator valve 7 is provided in the water side pipe of the additional adjustable final stage feedwater heater 01, is connected in parallel with the steam cooler 21, and is connected in series with the final stage feedwater heater 11. The feed water is fed from the outlet of a conventional final-stage feed water heater 11, enters a steam cooler 21 and an additional adjustable final-stage feed water heater 01 respectively in two paths for heating, and enters a steam cooler 03 for heating after the two paths of feed water are mixed. In this embodiment, the most economical feedwater temperature minus the temperature rise of the steam cooler 03 is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 21 are mixed, and is the result of the combined adjustment of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7. At this time, the temperature value obtained by subtracting the temperature rise of the steam cooler 03 from the most economical feedwater temperature under different loads is used as the combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the embodiment, and are not repeated here.

Detailed description of the invention twenty-four

Fig. 27 shows a twenty-fourth embodiment of the present invention, which differs from the twenty-third embodiment in that the system is configured such that the regulator valve 7 is provided in the water side pipe of the steam cooler 21, is connected in parallel with the additional adjustable final stage feedwater heater 01, and is connected in series with the final stage feedwater heater 11. The feed water is fed from the outlet of a conventional final-stage feed water heater 11, enters a steam cooler 21 and an additional adjustable final-stage feed water heater 01 respectively in two paths for heating, and enters a steam cooler 03 for heating after the two paths of feed water are mixed. In this embodiment, the most economical feedwater temperature minus the temperature rise of the steam cooler 03 is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 21 are mixed, and is the result of the combined adjustment of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7. At this time, the temperature value obtained by subtracting the temperature rise of the steam cooler 03 from the most economical feedwater temperature under different loads is used as the combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the embodiment, and are not repeated here.

Detailed description of the invention twenty-five

Fig. 28 shows a twenty-fifth embodiment of the present invention, which differs from the twenty-third embodiment in that the system is configured such that the adjusting valve 7 is provided in the water side pipe of the additional adjustable final stage feedwater heater 01, is connected in parallel with the steam cooler 21, and is connected in series with the steam cooler 03. The feed water is fed from the outlet of a conventional final-stage feed water heater 11, enters the steam cooler 03 for heating, and then enters the steam cooler 21 and an additional adjustable final-stage feed water heater 01 for heating respectively in two paths, and then enters the boiler economizer after being mixed. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 21 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Detailed description of the invention twenty-six

Fig. 29 shows a twenty-sixth embodiment of the present invention, which differs from the twenty-fifth embodiment in that the system is configured such that the regulator valve 7 is provided in the water side pipe of the steam cooler 21, and is connected in parallel with the additional adjustable final stage feedwater heater 01, and is connected in series with the steam cooler 03. The feed water is fed from the outlet of a conventional final-stage feed water heater 11, enters the steam cooler 03 for heating, and then enters the steam cooler 21 and an additional adjustable final-stage feed water heater 01 for heating respectively in two paths, and then enters the boiler economizer after being mixed. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 21 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Detailed description of the invention twenty-seven

Fig. 30 shows a twenty-seventh embodiment of the present invention, which differs from the twenty-fifth embodiment in that the system is configured such that the regulator valve 7 is provided in the water side pipe of the steam cooler 03, is connected in parallel with the steam cooler 21, and is connected in series with the final stage feedwater heater 11. The water is fed from the outlet of the conventional final-stage water heater 11, enters the steam cooler 21 and the steam cooler 03 respectively for heating in two paths, and enters the additional adjustable final-stage water heater 01 for heating after being mixed. In this embodiment, the most economical feedwater temperature minus the temperature value after the temperature rise of the additional adjustable final stage feedwater heater 01 is the feedwater temperature at which the outlet of the steam cooler 03 and the outlet of the steam cooler 21 are mixed, and is the result of the joint adjustment of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7. At this time, the most economical feedwater temperature under different loads is subtracted from the temperature value after the temperature rise of the additional adjustable final stage feedwater heater 01 to serve as the combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the embodiment, and are not repeated here.

Detailed description of the invention twenty-eight

Fig. 31 shows a twenty-eighth embodiment of the present invention, which differs from the twenty-seventh embodiment in that the system is configured such that the regulator valve 7 is provided in the water side pipe of the steam cooler 21, is connected in parallel with the steam cooler 03, and is connected in series with the final stage feedwater heater 11. The water is fed from the outlet of the conventional final-stage water heater 11, enters the steam cooler 21 and the steam cooler 03 respectively for heating in two paths, and enters the additional adjustable final-stage water heater 01 for heating after being mixed. In this embodiment, the most economical feedwater temperature minus the temperature value after the temperature rise of the additional adjustable final stage feedwater heater 01 is the feedwater temperature at which the outlet of the steam cooler 03 and the outlet of the steam cooler 21 are mixed, and is the result of the joint adjustment of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7. At this time, the most economical feedwater temperature under different loads is subtracted from the temperature value after the temperature rise of the additional adjustable final stage feedwater heater 01 to serve as the combined control target of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the embodiment, and are not repeated here.

Detailed description of the invention twenty-nine

Fig. 32 shows a twenty-ninth embodiment of the present invention, which is different from the twenty-seventh embodiment in that the system is configured such that the adjusting valve 7 is disposed on the water side pipeline of the steam cooler 03, is connected in parallel with the steam cooler 21, and is connected in series with the additional adjustable final-stage feedwater heater 01. The feed water is fed from the outlet of a conventional final-stage feed water heater 11, enters an additional adjustable final-stage feed water heater 01 for heating, and enters a steam cooler 03 and a steam cooler 21 for heating respectively in two paths, and then enters a boiler economizer after being mixed. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the steam cooler 03 and the outlet of the steam cooler 21 are mixed, and is the result of the joint adjustment of the additional adjustable final stage extraction regulator 02 and the water side regulator 7. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Detailed description of the invention thirty

Fig. 33 shows a thirty-third embodiment of the present invention, which differs from the twenty-ninth embodiment in that the system is configured such that a regulating valve 7 is provided in the water side pipe of the steam cooler 21, and is connected in parallel with the steam cooler 03, and is connected in series with an additional adjustable final stage feedwater heater 01. The feed water is fed from the outlet of a conventional final-stage feed water heater 11, enters an additional adjustable final-stage feed water heater 01 for heating, and enters a steam cooler 03 and a steam cooler 21 for heating respectively in two paths, and then enters a boiler economizer after being mixed. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the steam cooler 03 and the outlet of the steam cooler 21 are mixed, and is the result of the joint adjustment of the additional adjustable final stage extraction regulator 02 and the water side regulator 7. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Detailed description of the invention thirty-one

Fig. 34 is a thirty-first embodiment of the present invention, in which an additional adjustable post-final stage steam extraction port 0, an additional adjustable post-final stage steam extraction pipe 00, an additional adjustable post-final stage steam extraction regulating valve 02, a steam extraction pipe 00', a steam cooler 03 and an additional adjustable post-final stage feedwater heater 01 are added to a conventional final stage steam extraction port 1, final stage steam extraction 10 and final stage feedwater heater 11. The additional adjustable final stage steam extraction firstly sequentially enters the steam cooler 03 through the additional adjustable final stage steam extraction pipeline 00 and the additional adjustable final stage steam extraction regulating valve 02 to heat water supply, and then enters the additional adjustable final stage feed water heater 01 through the steam extraction pipeline 00' to heat water supply.

At the same time, the steam cooler 03 and the additional adjustable final-stage feedwater heater 01 are connected in series, and the water-side pipeline of the additional adjustable final-stage feedwater heater 01 is provided with a regulating valve 7, is connected in parallel with the steam cooler 21 and is connected in series with the conventional final-stage feedwater heater 11. The additional adjustable final stage steam extraction regulating valve 02 is utilized to regulate the steam extraction of the additional adjustable final stage steam extraction pipeline 00, so as to control the pressure behind the additional adjustable final stage steam extraction regulating valve 02; the feed water at the outlet of the final stage feed water heater 11 is split into two parts, one part is heated by the additional adjustable final stage feed water heater 01 and the steam cooler 03 in sequence, and the other part is heated by the steam cooler 21 and then mixed with the other part, and the mixture is used as final feed water to enter the boiler economizer. The water side pipeline of the additional adjustable final-stage feed water heater 01 is provided with a regulating valve 7 which can be used for controlling and regulating the feed water flow which is split into the additional adjustable final-stage feed water heater 01 and the steam cooler 21. Thus, the temperature of the feed water after mixing at the outlets of the steam cooler 03 and the steam cooler 21 is controlled by jointly adjusting the additional adjustable final stage steam extraction adjusting valve 02 and the adjusting valve 7.

In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the steam cooler 21 and the outlet of the steam cooler 03 are mixed, and is the result of the joint adjustment of the additional adjustable final stage extraction regulator 02 and the water side regulator 7.

The steam extraction pressure entering the steam cooler 03 and the additional adjustable final stage feed water heater 01 can be controlled by controlling the additional adjustable final stage steam extraction regulating valve 02; by controlling the water side regulating valve 7, the feed water flow rate distributed into the steam cooler 21 and the additional adjustable final stage feed water heater 01 can be controlled, and by controlling the two regulating valves in combination, the feed water temperature at which the steam cooler 21 and the outlet of the steam cooler 03 are mixed can be controlled.

Therefore, the control strategy of the present embodiment is:

firstly, determining the most economical water supply temperature value of the unit under different loads according to the conditions of boiler system configuration and the like, determining the additional adjustable post-final stage steam extraction ports which are optimally selected according to the high-pressure cylinder structure of a steam turbine and the operating load of the unit frequently, and further determining the additional adjustable post-final stage steam extraction pressure value corresponding to the sliding pressure operation of the additional adjustable post-final stage steam extraction ports with different loads. Thereby determining the adjustable pressure range of the additional adjustable final stage extraction regulating valve 02.

The most economical water supply temperature value under different loads is used as the combined control target of the additional adjustable post-final stage steam extraction regulating valve 02 and the water side regulating valve 7.

Meanwhile, in order to avoid that the difference between the water supply temperature value at the outlet of the steam cooler 03 and the water supply temperature value at the outlet of the steam cooler 21 is too large, which is not beneficial to the safety of a pipeline system, a maximum difference can be manually set and used as a feedback factor of the water side regulating valve 7 and the additional adjustable post-final stage steam extraction regulating valve 02, and once the safety difference is exceeded, the two regulating valves can be jointly regulated to control the difference to be within a safety range.

Detailed description of the invention thirty-two

Fig. 35 shows a thirty-second embodiment of the present invention, which is different from the thirty-first embodiment in that the steam cooler 03 and the additional adjustable final stage feedwater heater 01 are connected in series in terms of system configuration, and the regulator valve 7 is provided in the water side pipe of the steam cooler 21 and connected in parallel with the steam cooler 03 and the additional adjustable final stage feedwater heater 01. The feed water at the outlet of the final stage feed water heater 11 is split into two parts, one part is heated by the additional adjustable final stage feed water heater 01 and the steam cooler 03 in sequence, and the other part is heated by the steam cooler 21 and then mixed with the other part, and the mixture is used as final feed water to enter the boiler economizer. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the steam cooler 03 and the outlet of the steam cooler 21 are mixed, and is the result of the joint adjustment of the additional adjustable final stage extraction regulator 02 and the water side regulator 7. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Detailed description of the invention thirty-three

Fig. 36 shows a thirty-third embodiment of the present invention, which differs from the thirty-first embodiment in that the additional adjustable final stage feedwater heater 01 and the steam cooler 03 are connected in series in terms of system configuration, and the steam cooler 03 is provided with a regulating valve 7 on the water side pipe, and connected in parallel with the steam cooler 03 and the additional adjustable final stage feedwater heater 01. The feed water at the outlet of the final stage feed water heater 11 is split into two parts, one part is heated by the steam cooler 03 and the additional adjustable final stage feed water heater 01 in sequence, and the other part is heated by the steam cooler 21 and then mixed with the steam cooler, and the mixed feed water enters the boiler economizer as final feed water. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 21 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Detailed description of the invention thirty-four

Fig. 37 shows a thirty-fourth embodiment of the present invention, which differs from the thirty-third embodiment in that the additional adjustable final-stage feedwater heater 01 and the steam cooler 03 are connected in series in terms of system configuration, and the adjusting valve 7 is provided in the water-side pipe of the steam cooler 21 and connected in parallel with the additional adjustable final-stage feedwater heater 01 and the steam cooler 03. The feed water at the outlet of the final stage feed water heater 11 is split into two parts, one part is heated by the steam cooler 03 and the additional adjustable final stage feed water heater 01 in sequence, and the other part is heated by the steam cooler 21 and then mixed with the steam cooler, and the mixed feed water enters the boiler economizer as final feed water. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 21 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Description of the preferred embodiments thirty-five

Fig. 38 shows a thirty-fifth embodiment of the present invention, which differs from the thirty-third embodiment in that the steam cooler 03 and the steam cooler 21 are connected in series in terms of system configuration, and the adjusting valve 7 is provided in the water side pipe of the additional adjustable final stage feedwater heater 01, and is connected in parallel with the steam cooler 03 and the steam cooler 21. The feed water at the outlet of the final feed water heater 11 is split into two parts, one part is heated by the steam cooler 21 and the steam cooler 03 in sequence, the other part is heated by the additional adjustable final feed water heater 01, and then the two parts are mixed and enter the boiler economizer as final feed water. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 03 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Description of the preferred embodiments thirty-six

Fig. 39 shows a thirty-sixth embodiment of the present invention, which differs from the thirty-fifth embodiment in that the steam cooler 21 and the steam cooler 03 are connected in series in terms of system configuration, and the regulator valve 7 is provided in the water side pipe of the additional adjustable final stage feedwater heater 01, and is connected in parallel with the steam cooler 21 and the steam cooler 03. The feed water at the outlet of the final feed water heater 11 is split into two parts, one part is heated by the steam cooler 03 and the steam cooler 21 in sequence, and the other part is heated by the additional adjustable final feed water heater 01, and then the two parts are mixed and enter the boiler economizer as final feed water. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 21 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Description of the preferred embodiments thirty-seven

Fig. 40 shows a thirty-seventh embodiment of the present invention, which is different from the thirty-fifth embodiment in that the steam cooler 03 and the steam cooler 21 are connected in series in terms of system configuration, and the adjusting valve 7 is provided on the water side pipe of the steam cooler 21 and connected in parallel with the additional adjustable final stage feedwater heater 01. The feed water at the outlet of the final feed water heater 11 is split into two parts, one part is heated by the steam cooler 21 and the steam cooler 03 in sequence, the other part is heated by the additional adjustable final feed water heater 01, and then the two parts are mixed and enter the boiler economizer as final feed water. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 03 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Detailed description of the invention thirty-eight

Fig. 41 shows a thirty-eighth embodiment of the present invention, which is different from the thirty-seventh embodiment in terms of system configuration, in which the steam cooler 21 and the steam cooler 03 are connected in series, and the water side pipe of the steam cooler 03 is provided with a regulating valve 7, and is connected in parallel with an additional adjustable final stage feedwater heater 01. The feed water at the outlet of the final feed water heater 11 is split into two parts, one part is heated by the steam cooler 03 and the steam cooler 21 in sequence, and the other part is heated by the additional adjustable final feed water heater 01, and then the two parts are mixed and enter the boiler economizer as final feed water. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 21 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Detailed description of the invention thirty-nine

Fig. 42 shows a thirty-ninth embodiment of the present invention, which is different from the thirty-seventh embodiment in that the additional adjustable final stage feedwater heater 01 and the steam cooler 21 are connected in series in terms of system configuration, and the adjusting valve 7 is provided in the water side pipe of the steam cooler 03 and connected in parallel with the additional adjustable final stage feedwater heater 01 and the steam cooler 21. The feed water at the outlet of the final feed water heater 11 is split into two parts, one part is heated by the steam cooler 03, the other part is sequentially heated by the steam cooler 21 and the additional adjustable final feed water heater 01, and then the two parts are mixed and enter the boiler economizer as final feed water. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 03 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Description of the preferred embodiments forty

Fig. 43 shows a fortieth embodiment of the present invention, which differs from thirty-ninth embodiments in that the additional adjustable final stage feedwater heater 01 and the steam cooler 21 are connected in series in terms of system configuration, and the adjusting valve 7 is provided in the water side pipe of the steam cooler 03 and connected in parallel with the additional adjustable final stage feedwater heater 01 and the steam cooler 21. The feed water at the outlet of the final feed water heater 11 is split into two parts, one part is heated by the steam cooler 03, and the other part is sequentially heated by the additional adjustable final feed water heater 01 and the steam cooler 21, and then the two parts are mixed and enter the boiler economizer as final feed water. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the steam cooler 21 and the outlet of the steam cooler 03 are mixed, and is the result of the joint adjustment of the additional adjustable final stage extraction regulator 02 and the water side regulator 7. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Description of the preferred embodiments forty-one

Fig. 44 shows a fortieth embodiment of the present invention, which is different from thirty-ninth embodiments in terms of system configuration, in which an additional adjustable post-stage feedwater heater 01 and a steam cooler 21 are connected in series, and in which a regulator valve 7 is provided in a water side pipe of the steam cooler 21, and in which the steam cooler 03 is connected in parallel with the additional adjustable post-stage feedwater heater 01 and the steam cooler 21. The feed water at the outlet of the final feed water heater 11 is split into two parts, one part is heated by the steam cooler 03, the other part is sequentially heated by the steam cooler 21 and the additional adjustable final feed water heater 01, and then the two parts are mixed and enter the boiler economizer as final feed water. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the additional adjustable final stage feedwater heater 01 and the outlet of the steam cooler 03 are mixed, and is the result of the additional adjustable final stage extraction regulating valve 02 and the water side regulating valve 7 being jointly regulated. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

Description of the preferred embodiment forty-two

Fig. 45 shows a forty-second embodiment of the present invention, which differs from the forty-first embodiment in that the steam cooler 21 and the additional adjustable final stage feedwater heater 01 are connected in series in terms of system configuration, the regulator valve 7 is provided in the water side pipe of the additional adjustable final stage feedwater heater 01, and the steam cooler 03 is connected in parallel with the steam cooler 21 and the additional adjustable final stage feedwater heater 01. The feed water at the outlet of the final feed water heater 11 is split into two parts, one part is heated by the steam cooler 03, and the other part is sequentially heated by the additional adjustable final feed water heater 01 and the steam cooler 21, and then the two parts are mixed and enter the boiler economizer as final feed water. In this embodiment, the most economical feedwater temperature is the feedwater temperature at which the outlet of the steam cooler 21 and the outlet of the steam cooler 03 are mixed, and is the result of the joint adjustment of the additional adjustable final stage extraction regulator 02 and the water side regulator 7. At this time, the most economical feedwater temperature values under different loads are used as the combined control targets of the additional adjustable final stage steam extraction regulating valve 02 and the water side regulating valve 7, and the other control modes are the same as those of the nineteenth embodiment, and are not described in detail here.

The foregoing describes in detail preferred embodiments of the present invention. It should be noted that, the adjustable feedwater backheating system of the present invention may have various combinations according to whether the steam coolers are disposed on the water side, whether the water side adjusting valves are disposed on the water side, different numbers of steam coolers, different numbers of water side adjusting valves, and the connection modes (serial connection and parallel connection) with the additional adjustable final stage feedwater heater.

It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention by one of ordinary skill in the art without undue burden. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.

Claims

1. The control method of the adjustable feedwater heat recovery system for the thermal power plant at least comprises a high-pressure cylinder of a steam turbine, a conventional non-adjustable final stage steam extraction port and a conventional non-adjustable final stage feedwater heater on the high-pressure cylinder, and is characterized by further comprising an additional adjustable final stage steam extraction port on the high-pressure cylinder, wherein the steam extraction pressure of the additional adjustable final stage steam extraction port is higher than 1.2 times of the conventional non-adjustable final stage steam extraction pressure of the high-pressure cylinder and lower than 2.5 times of the conventional non-adjustable final stage steam extraction pressure of the high-pressure cylinder;

The steam extraction regulating valve is arranged on the additional adjustable final stage steam extraction pipeline and is used for regulating the steam extraction in the additional adjustable final stage steam extraction pipeline so as to control the outlet pressure of the steam extraction regulating valve to control the outlet temperature of the additional adjustable final stage feedwater heater, so as to meet the final feedwater temperature required under different working conditions;

the control method based on the adjustable feedwater heat regenerative system comprises the following steps:

Step a: setting the most economic water supply temperature values under different loads according to the configuration of the boiler system, and converting the most economic water supply temperature values under different loads into additional adjustable final stage steam extraction pressure values according to the configuration of the water supply side system;

step b: selecting a reasonable additional adjustable final stage steam extraction port to obtain additional adjustable final stage steam extraction pressure values under different loads of sliding pressure operation;

step c: comparing the additional adjustable final stage steam extraction pressure values under different loads of the step a and the step b, and if the additional adjustable final stage steam extraction pressure value of the step a is larger than the additional adjustable final stage steam extraction pressure value of the step b under the same load, feeding back the additional adjustable final stage steam extraction pressure value of the step b to a steam extraction regulating valve on an additional adjustable final stage steam extraction pipe to serve as a control target of the additional adjustable final stage steam extraction pressure value; under the same load, if the additional adjustable final stage steam extraction pressure value of the step a is smaller than the additional adjustable final stage steam extraction pressure value of the step b, feeding back the additional adjustable final stage steam extraction pressure value of the step a to a steam extraction regulating valve on an additional adjustable final stage steam extraction pipe to serve as a control target of the additional adjustable final stage steam extraction regulating valve; under the same load, if the additional adjustable final stage steam extraction pressure value of the step a is equal to the additional adjustable final stage steam extraction pressure value of the step b, the additional adjustable final stage steam extraction pressure value of the step a or the step b is fed back to a steam extraction regulating valve on an additional adjustable final stage steam extraction pipe to serve as a control target of the additional adjustable final stage steam extraction valve.

2. The control method for an adjustable feedwater heat recovery system for a thermal power plant of claim 1, further comprising at least one steam cooler, wherein a water side of at least one of said steam coolers is connected in series with a water side inlet or outlet of said additional adjustable post-stage feedwater heater.

3. The control method for an adjustable feedwater heat recovery system for a thermal power plant of claim 1, further comprising at least one steam cooler, wherein a water side of at least one of said steam coolers is connected in parallel with a water side of said additional adjustable post-stage feedwater heater.

4. The control method for an adjustable feedwater heat recovery system of a thermal power plant of claim 2, further comprising at least one water side regulator valve, wherein at least one of said water side regulator valves is connected in parallel with said additional adjustable post-stage feedwater heater and in series with at least one of said steam coolers.

5. The control method for an adjustable feedwater heat recovery system of a thermal power plant of claim 3, further comprising at least one water side regulator valve, wherein at least one of said water side regulator valves is connected in series with said additional adjustable post-stage feedwater heater and in parallel with at least one of said steam coolers.

6. The control method for an adjustable feedwater heat recovery system of a thermal power plant of claim 3, further comprising at least one water side regulator valve, wherein at least one of said water side regulator valves is connected in series with at least one of said steam coolers and in parallel with an additional adjustable post-final stage feedwater heater.