阅读说明：本技术 一种解决深度调峰运行加热器疏水不畅的旁路系统优化方法 (Bypass system optimization method for solving problem of unsmooth drainage of deep peak shaving operation heater ) 是由 高庆 朱蓬勃 屈杰 马汀山 居文平 张京华 杨宁辉 于 2021-09-06 设计创作，主要内容包括：本发明公开了一种解决深度调峰运行加热器疏水不畅的旁路系统优化方法,本发明通过对机组运行日志进行收集分析,掌握了当前加热器系统的运行现状和加热器系统发生疏水不畅的负荷边界临界区间,依据加热器系统中的水力热力特性计算优化结果,在加热器系统的疏水调节阀管路系统处增加旁路管路,最后根据各个疏水调节阀管路与旁路管路间的流量分配与水力设计值的偏差,调整旁路管路的通径,完成优化设计。本发明解决了由于疏水调节阀选型不当或管路布置不合理造成的沿程阻力较大的问题,避免低负荷运行时危急疏水阀门打开,高品质工质直接灌入凝汽器,进而达到减少损提升机组效率的目的,对改善机组安全经济运行具有十分重要的意义。(The invention discloses a bypass system optimization method for solving the problem of poor drainage of a deep peak shaving operation heater. The invention solves the problems of improper type selection or improper pipeline arrangement of the hydrophobic adjusting valveThe problem of relatively large on-way resistance is reasonably caused, the opening of an emergency drain valve in low-load operation is avoided, high-quality working media are directly poured into a condenser, and the reduction of the on-way resistance is further achieved The purpose of improving the efficiency of the unit is reduced, and the method has very important significance for improving the safe and economic operation of the unit.)

1. A bypass system optimization method for solving the problem of unsmooth drainage of a deep peak shaving operation heater is characterized by comprising the following steps:

s1, obtaining the current operation state of the heater system according to the unit operation log, and analyzing a load boundary critical interval occurring when the drainage is not smooth in the heater system;

s2, analyzing the connection form of the heater system pipeline according to a unit thermodynamic system pipeline arrangement completion drawing and a field survey surveying and mapping layout drawing;

s3, analyzing and calculating the hydraulic thermodynamic characteristics in the heater system to obtain the resistance characteristics and the inlet and outlet flow parameters of each component of the pipe network system in the heater system;

s4, adding a bypass pipeline at a drain regulating valve pipeline system of the heater system;

s5, establishing a calculation model after optimization design, analyzing and calculating the hydraulic thermal characteristics of auxiliary equipment in the heater system, and comparing the flow distribution between each hydrophobic regulating valve pipeline and each bypass pipeline with the deviation of a hydraulic design value;

and S6, adjusting the drift diameter of the bypass pipeline according to the deviation between the flow distribution between each drainage regulating valve pipeline and the bypass pipeline and the hydraulic design value, and finishing the optimization design.

2. The method for optimizing the bypass system for solving the problem of poor drainage of the deep peak shaving operation heater according to claim 1, wherein in S1, the unit operation log comprises design data of the heater, a current water level set value of the heater, a maintenance record, maintenance content and an emergency repair record of the heater, a performance index of the heater under a current rated load working condition, the unit operation log, a load boundary of the heater with poor drainage and historical operation data of the steam turbine steam extraction system and the heater system under the state, and the design data comprises a computer book and a specification.

3. The method for optimizing the bypass system for solving the problem of poor drainage of the heaters in deep peak shaving operation according to claim 1, wherein in step S1, when analyzing the problem of poor drainage in the heater system and the critical interval of load boundary generated by the problem, the load generation interval of poor drainage of each high-low pressure heater and the load interval of critical drainage valve adjustment are found out by referring to the operation parameters such as unit load, parameters of each steam extraction pipeline of the steam turbine, parameters of each steam inlet and drainage system of each heater, and water level set values of the heaters.

4. The method for optimizing the bypass system to solve the problem of poor drainage of the deep peak shaving operation heater according to claim 1, the method is characterized in that in S2, the unit thermodynamic system pipeline arrangement completion drawing and the field survey surveying and mapping layout drawing comprise a water supply system flow chart, a high-pressure heater system drawing, a low-pressure heater system drawing, a deaerator system drawing, an electric water supply pump unit layout drawing, a steam feed pump unit layout drawing, a high-pressure water supply pipeline installation drawing, a low-pressure water supply pipeline installation drawing, a high-pressure heater drainage pipeline empty drawing, a high-pressure heater normal drainage pipeline arrangement drawing, a high-pressure heater emergency drainage pipeline arrangement drawing, a high-pressure heater water discharge and air discharge pipeline installation drawing, a high-pressure heater support hanger detail drawing, a low-pressure heater normal drainage pipeline arrangement drawing, a low-pressure heater emergency drainage pipeline arrangement drawing, a low-pressure heater water discharge and air discharge pipeline installation drawing and a low-pressure heater support hanger detail drawing.

5. The method for optimizing the bypass system for solving the problem of poor drainage of the heaters in the deep peaking operation according to claim 1, wherein in S3, the resistance characteristics and the inlet and outlet flow parameters of each component of the pipe network system in the heater system are calculated as follows:

the basic equation for calculating the pressure loss of the circular pipeline flow is as follows:

in the formula: p₂Is the pipeline outlet pressure; p₁Is the pipeline inlet pressure; m is₁Is the mass flow rate; a is the sectional area of the pipeline; rho is the density of the flowing working medium; d is the diameter of the pipeline; l is the length of the pipeline; f is the coefficient of friction resistance;

wherein a Colebrook-White model is adopted for calculating the resistance loss of the straight pipe, and the calculation method is as follows:

when the flow is in a laminar state Re < 2000,

when the flow is in a turbulent state Re >2000,

the basic equation for the calculation of the flow pressure loss of the elbow is:

in the formula: k is a radical of_bIs the elbow flow loss coefficient; c_ReIs the Reynolds correction factor; c_fThe surface roughness correction factor; (ii) a Rho is the density of the flowing working medium; v is the pipeline flow velocity;

the basic equation for calculating the flow pressure loss of a valve is:

in the formula: k is the valve flow loss coefficient; c_ReIs the reynolds number correction factor.

6. The method for optimizing the bypass system for solving the problem of poor drainage of the heater in the deep peak shaver operation according to claim 1, wherein in S4, the added bypass pipeline needs to be based on the safety and stability of the heater system, and the related standards of the power industry are referred to, wherein the related standards of the power industry include design specifications for steam-water pipelines of DL5045-2016 thermal power plants, design specifications for power pipelines of GB 507642012 power plants, guide rules for water inlet and cold steam of DL/T834-2003 thermal power plants, and recommended implementation rules for preventing water damage of steam turbines for ASME TDP-1-2013 power generation.

7. The method for optimizing the bypass system for solving the problem of poor drainage of the heater during deep peak shaving operation according to claim 1, wherein in S6, when a small-diameter bypass pipeline is added to the heater drainage regulating valve pipeline system, the pipe diameter selection calculation formula of the bypass pipeline is as follows:

R₃＝F₁R₁+F₂R₂

wherein R is₁The diameter of the drainage pipeline; r₂The drift diameter of the drain regulating valve is adjusted; r₃The diameter of the bypass pipeline; f₁Weighting coefficients related to the diameter of the hydrophobic pipeline; f₂Weighting coefficients related to the drift diameter of the hydrophobic regulating valve;

wherein F₁、F₂Comprehensively determining and selecting after hydraulic calculation and analysis.

8. The method for optimizing the bypass system for solving the problem of poor drainage of the deep peak shaving operation heater according to claim 1, wherein in S4, the bypass pipeline comprises a straight vertically extending pipe section, an arc transition section and a straight parallel pipe section;

vertically extending straight pipe section L₁The length calculation formula of (a) is as follows:

L₁＝f₁R₃

radius R of arc transition section₄The calculation formula of (2) is as follows:

R₄＝f₂R₃

parallel straight pipe section L₂The calculation formula of (2) is as follows:

L₂＝f₃R₃

wherein R is₃The diameter of the bypass pipeline; f. of₁Weighting coefficients associated with the vertically extending straight tube sections; f. of₂Weighting coefficients related to the middle arc transition section; f. of₃Weighting coefficients associated with the parallel straight tube sections;

wherein f is₁、f₂And f₃The selection of the method is to optimize the pipeline and the arc transition section molded line by a numerical simulation method with the minimum pressure drop as an optimization target and then determine.

9. The method for optimizing the bypass system for solving the problem of poor drainage of the heater in the deep peaking operation of the claim 1, wherein in the step S5, the deviation processing formula of each drainage regulating valve pipeline and the hydraulic design value of the auxiliary equipment in the heater system is as follows:

in the formula, delta is a deviation calculation result; m is_JCalculating flow for drain control valve pipeline；m_SDesigning a flow for hydraulic calculation of auxiliary equipment in the heater system;

and when the deviation calculation result is less than 1%, the optimization scheme is considered as a reasonable result.

10. The optimization method of the bypass system for solving the problem of poor drainage of the deep peak shaving operation heater according to claim 1, wherein after the optimization design is completed, an equivalent enthalpy drop method is adopted to respectively calculate the work capacity reduction amount of the heater system and the device efficiency reduction value, and finally the operation economy of the unit is evaluated;

the method of calculating the reduction in capacity of the heater system is as follows:

when the high-pressure heater with the beta fraction drains water and enters a deaerator NO.m, the equivalent heat drop of new steam is increased as follows:

when the drained water is discharged into the condenser, the equivalent heat drop of the new steam is increased as follows:

the work loss of the switching drainage is the work difference of the two recovery modes, i.e.

ΔH＝H₁-H₂

In the formula: beta is the share of water entering the condenser, gamma is 1kg of heat release of water drainage, eta is the efficiency of the heater,in order to be the specific enthalpy of hydrophobicity,specific enthalpy of the hot well water outlet;

the calculation method of the device efficiency reduction value is as follows:

wherein, Δ H is the system work capacity reduction amount, and H is the work capacity before the heater system is optimized.

Technical Field

The invention belongs to the field of thermal power generation, and particularly relates to a bypass system optimization method for solving the problem of unsmooth drainage of a deep peak shaving operation heater.

Background

In recent years, with the rapid increase of installed capacities of wind power generation and photovoltaic power generation, due to the characteristics of randomness, intermittence, instability and the like, the large-proportion access has a great influence on the stability of a power grid. Compared with national regions such as America, Europe and the like, the gas generating set in China is few, the power supply for quickly changing load and stabilizing power grid fluctuation is insufficient, and the thermal power generating set has to bear the task of power grid peak shaving. Therefore, in order to improve the consumption capacity of a power grid on renewable energy power generation, a thermal power generating unit needs to be further upgraded and transformed to enable the unit to have deep peak regulation capacity, the goal is that part of power plants with implementation conditions are expected to reach the international advanced level by strengthening technical communication and cooperation at home and abroad, and the minimum technical output of pure condensation working conditions reaches 20-25% when the unit does not put oil and stably burns.

When the deep peak regulation operation of the steam turbine, the pressure difference between every stage of steam extraction is reduced, the motive power of the heater in a step-by-step self-flowing mode is weakened, when the selection of a drainage regulating valve is improper or the on-way resistance of pipeline arrangement is large, the phenomenon of unsmooth drainage is easily caused, so that an emergency drainage valve is opened, high-quality working media directly enter a condenser, the circulation efficiency of the unit is reduced, the great energy loss is caused, the heat load of the condenser is aggravated, the vacuum of the unit is possibly further influenced, and the operation risk is caused. Therefore, the drainage system of the existing heater of the unit is optimized, the problem of poor drainage under low load is solved, and the method has great significance for improving the economic safety of unit operation.

Disclosure of Invention

The invention aims to overcome the defects, provides a bypass system optimization method for solving the problem of unsmooth drainage of a heater in deep peak shaving operation, can optimize the drainage system of the existing heater of a unit, solves the problem of large on-way resistance caused by improper selection of a drainage regulating valve or unreasonable pipeline arrangement by adding a small-diameter bypass pipeline at a pipeline system of a normal drainage regulating valve of an initially designed heater, avoids opening of an emergency drainage valve in low-load operation and direct filling of high-quality working medium into a condenser, and further achieves the aim of reducing the problem of unsmooth drainage of the heater in deep peak shaving operationThe purpose of improving efficiency is lost.

In order to achieve the above object, the present invention comprises the steps of:

s1, obtaining the current operation state of the heater system according to the unit operation log, and analyzing a load boundary critical interval occurring when the drainage is not smooth in the heater system;

s2, analyzing the connection form of the heater system pipeline according to a unit thermodynamic system pipeline arrangement completion drawing and a field survey surveying and mapping layout drawing;

s3, analyzing and calculating the hydraulic thermodynamic characteristics in the heater system to obtain the resistance characteristics and the inlet and outlet flow parameters of each component of the pipe network system in the heater system;

s4, adding a bypass pipeline at a drain regulating valve pipeline system of the heater system;

s5, establishing a calculation model after optimization design, analyzing and calculating the hydraulic thermal characteristics of auxiliary equipment in the heater system, and comparing the flow distribution between each hydrophobic regulating valve pipeline and each bypass pipeline with the deviation of a hydraulic design value;

and S6, adjusting the drift diameter of the bypass pipeline according to the deviation between the flow distribution between each drainage regulating valve pipeline and the bypass pipeline and the hydraulic design value, and finishing the optimization design.

In S1, the unit operation log includes design data of the heater, a current water level setting value of the heater, a repair record, repair content and a repair record of the heater, a performance index of the heater under a current rated load condition, an operation log of the unit, a load boundary where the heater is not drained smoothly, and historical operation data of the steam extraction system of the steam turbine and the heater system in the state, and the design data includes a computer book and a specification.

In S1, when analyzing the drainage problem and the critical load boundary interval, the load occurrence interval of the high and low pressure heaters and the load interval of the emergency drainage valve operation are found out according to the unit load, the steam extraction pipeline parameters of the steam turbine, the steam inlet and drainage system parameters of the heaters, the water level set value of the heaters and other operation parameters.

In S2, the unit thermodynamic system pipeline layout completion drawing and the field survey surveying and mapping layout drawing include a water supply system flow diagram, a high pressure heater system diagram, a low pressure heater system diagram, a deaerator system diagram, an electric feed pump unit layout drawing, a steam feed pump unit layout drawing, a high pressure water supply pipeline installation drawing, a low pressure water supply pipeline installation drawing, a high pressure heater drain pipeline empty drawing, a high pressure heater normal drain pipeline layout drawing, a high pressure heater emergency drain pipeline layout drawing, a high pressure heater bleed air duct installation drawing, a high pressure heater support hanger detail drawing, a low pressure heater normal drain pipeline layout drawing, a low pressure heater emergency drain pipeline layout drawing, a low pressure heater bleed air duct installation drawing and a low pressure heater support hanger detail drawing.

In S3, the method for calculating the resistance characteristics and inlet/outlet flow parameters of each component of the piping system in the heater system is as follows:

the basic equation for calculating the pressure loss of the circular pipeline flow is as follows:

in the formula: p₂Is the pipeline outlet pressure; p₁Is the pipeline inlet pressure; m is₁Is the mass flow rate; a is the sectional area of the pipeline; rho is the density of the flowing working medium; d is the diameter of the pipeline; l is the length of the pipeline; f is the coefficient of friction resistance;

wherein a Colebrook-White model is adopted for calculating the resistance loss of the straight pipe, and the calculation method is as follows:

when the flow is in a laminar state Re < 2000,

when the flow is in a turbulent state Re >2000,

the basic equation for the calculation of the flow pressure loss of the elbow is:

in the formula: k is a radical of_bIs the elbow flow loss coefficient; c_ReIs the Reynolds correction factor; c_fThe surface roughness correction factor; (ii) a Rho is the density of the flowing working medium; v is the pipeline flow velocity;

the basic equation for calculating the flow pressure loss of a valve is:

in the formula: k is the valve flow loss coefficient; c_ReIs the reynolds number correction factor.

In S4, the added bypass pipeline needs to be based on the safety and stability of the heater system, and meanwhile, the related standards of the power industry are referred to, wherein the related standards of the power industry comprise ' design specification of steam-water pipelines of DL5045-2016 thermal power plants ', ' design specification of power pipelines of GB 507642012 power plants ', ' guide rule of preventing water inflow and cold steam of turbines of DL/T834-2003 thermal power plants

Recommended practice regulations on water damage prevention of steam turbines for ASME TDP-1-2013 power generation.

In S6, when a small-diameter bypass pipeline is added to the heater drain control valve pipeline system, the pipe diameter selection calculation formula of the bypass pipeline is as follows:

R₃＝F₁R₁+F₂R₂

wherein R is₁The diameter of the drainage pipeline; r₂The drift diameter of the drain regulating valve is adjusted; r₃The diameter of the bypass pipeline; f₁Weighting coefficients related to the diameter of the hydrophobic pipeline; f₂Weighting coefficients related to the drift diameter of the hydrophobic regulating valve;

wherein F₁、F₂Comprehensively determining and selecting after hydraulic calculation and analysis.

In S4, the bypass pipeline comprises a vertically extending straight pipe section, an arc transition section and a parallel straight pipe section;

vertically extending straight pipe section L₁The length calculation formula of (a) is as follows:

L₁＝f₁R₃

radius R of arc transition section₄The calculation formula of (2) is as follows:

R₄＝f₂R₃

parallel straight pipe section L₂The calculation formula of (2) is as follows:

L₂＝f₃R₃

wherein R is₃The diameter of the bypass pipeline; f. of₁Weighting coefficients associated with the vertically extending straight tube sections; f. of₂Weighting coefficients related to the middle arc transition section; f. of₃Weighting coefficients associated with the parallel straight tube sections;

wherein f is₁、f₂And f₃The selection of the method is to optimize the pipeline and the arc transition section molded line by a numerical simulation method with the minimum pressure drop as an optimization target and then determine.

In S5, the deviation processing formula of the hydraulic design values of each drain control valve pipeline and the auxiliary equipment in the heater system is as follows:

in the formula, delta is a deviation calculation result; m is_JCalculating the flow of the pipeline of the drainage regulating valve; m is_SDesigning a flow for hydraulic calculation of auxiliary equipment in the heater system;

and when the deviation calculation result is less than 1%, the optimization scheme is considered as a reasonable result.

After the optimization design is completed, an equivalent enthalpy drop method is adopted to respectively calculate the work capacity reduction amount of the heater system and the device efficiency reduction value, and finally the operation economy of the unit is evaluated;

the method of calculating the reduction in capacity of the heater system is as follows:

when the high-pressure heater with the beta fraction drains water and enters a deaerator NO.m, the equivalent heat drop of new steam is increased as follows:

when the drained water is discharged into the condenser, the equivalent heat drop of the new steam is increased as follows:

the work loss of the switching drainage is the work difference of the two recovery modes, i.e.

ΔH＝H₁-H₂

In the formula: beta is the share of water entering the condenser, gamma is 1kg of water discharging heat release, eta is the heater effectThe ratio of the total weight of the particles,in order to be the specific enthalpy of hydrophobicity,specific enthalpy of the hot well water outlet;

the calculation method of the device efficiency reduction value is as follows:

wherein, Δ H is the system work capacity reduction amount, and H is the work capacity before the heater system is optimized.

Compared with the prior art, the method provided by the invention has the advantages that the current running state of the heater system and the critical interval of the load boundary with the heater system subjected to drainage difficulty are mastered by collecting and analyzing the unit running logs, the optimization result is calculated according to the hydraulic thermal characteristics in the heater system, the bypass pipeline is added at the drainage regulating valve pipeline system of the heater system, and finally the drift diameter of the bypass pipeline is adjusted according to the deviation of the flow distribution and the hydraulic design value between each drainage regulating valve pipeline and the bypass pipeline, so that the optimization design is completed. The invention solves the problem of large on-way resistance caused by improper type selection of the drain control valve or unreasonable pipeline arrangement, avoids opening of an emergency drain valve in low-load operation, directly injects high-quality working medium into a condenser, and further achieves the aim of reducingThe purpose of improving the efficiency of the unit is reduced, and the method has very important significance for improving the safe and economic operation of the unit.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a plan view of a drainage system of a primary heater of a power plant according to an embodiment of the present invention;

FIG. 3 is a plan view of a drainage system of a heater optimized for a power plant in accordance with an embodiment of the present invention;

FIG. 4 is a three-dimensional view of a drainage system of a heater optimized for a power plant in accordance with an embodiment of the present invention;

FIG. 5 is a top view of a power plant optimized heater drainage system according to an embodiment of the present invention;

the system comprises a first-level heater, a second-level heater, a third-level heater, a fourth-level heater, a drain adjusting valve, a fourth-level heater, a fourth-drain adjusting valve, a fourth-level heater, a fourth-adjusting valve, a fourth-level heater, a fourth-adjusting valve, a bypass pipeline, a fourth-level heater, a fourth-adjusting valve, a bypass pipeline, a fourth-level heater, a fourth-bypass pipeline, a fourth-stage heater, a fourth-.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1, the present invention comprises the steps of:

the invention comprises the following steps:

s1, obtaining the current operation state of the heater system according to the unit operation log, and analyzing a load boundary critical interval occurring when the drainage is not smooth in the heater system;

the unit operation log comprises design data of the heater, a current water level set value of the heater, a maintenance record, maintenance content and a first-aid repair record of the heater, performance indexes of the heater under a current rated load working condition, the unit operation log, a load boundary with poor drainage of the heater and historical operation data of the steam extraction system of the steam turbine and the heater system under the state, wherein the design data comprises a calculation book and a specification.

When the problem of unsmooth drainage in a heater system and a load boundary critical interval generated by the problem are analyzed, the load generation interval of unsmooth drainage of each high-low pressure heater and the load interval of emergency drainage valve action are found out by referring to the unit load, the parameters of each steam extraction pipeline of the steam turbine, the parameters of the steam inlet and drainage system of each heater, the set value of the water level of the heater and other operation parameters.

S2, analyzing the connection form of the heater system pipeline according to a unit thermodynamic system pipeline arrangement completion drawing and a field survey surveying and mapping layout drawing;

the unit thermodynamic system pipeline arrangement completion drawing and the field survey surveying and mapping layout drawing comprise a water supply system flow chart, a high-pressure heater system drawing, a low-pressure heater system drawing, a deaerator system drawing, an electric feed pump unit layout drawing, a steam feed pump unit layout drawing, a high-pressure water supply pipeline installation drawing, a low-pressure water supply pipeline installation drawing, a high-pressure heater drainage pipeline empty drawing, a high-pressure heater normal drainage pipeline arrangement drawing, a high-pressure heater critical drainage pipeline arrangement drawing, a high-pressure heater water and gas discharge pipeline installation drawing, a high-pressure heater support hanger detailed drawing, a low-pressure heater normal drainage pipeline arrangement drawing, a low-pressure heater critical drainage pipeline arrangement drawing, a low-pressure heater water and gas discharge pipeline installation drawing and a low-pressure heater support hanger detailed drawing.

S3, analyzing and calculating the hydraulic thermodynamic characteristics in the heater system to obtain the resistance characteristics and the inlet and outlet flow parameters of each component of the pipe network system in the heater system; the method for calculating the resistance characteristics and the inlet and outlet flow parameters of each component of the pipe network system in the heater system comprises the following steps:

the basic equation for calculating the pressure loss of the circular pipeline flow is as follows:

in the formula: p₂Is the pipeline outlet pressure; p₁Is the pipeline inlet pressure; m is₁Is the mass flow rate; a is the sectional area of the pipeline; rho is the density of the flowing working medium; d is the diameter of the pipeline; l is the length of the pipeline; f is the coefficient of friction resistance;

wherein a Colebrook-White model is adopted for calculating the resistance loss of the straight pipe, and the calculation method is as follows:

when the flow is in a laminar state Re < 2000,

when the flow is in a turbulent state Re >2000,

the basic equation for the calculation of the flow pressure loss of the elbow is:

in the formula: k is a radical of_bIs the elbow flow loss coefficient; c_ReIs the Reynolds correction factor; c_fThe surface roughness correction factor; (ii) a Rho is the density of the flowing working medium; v is the pipeline flow velocity;

the basic equation for calculating the flow pressure loss of a valve is:

in the formula: k is the valve flow loss coefficient; c_ReIs the reynolds number correction factor.

S4, on the basis of ensuring the safety and stability of the heater system, and referring to the relevant standards of the power industry, a bypass pipeline is added at the pipeline system of the drain regulating valve of the heater system; relevant standards of the power industry include 'design specifications of steam-water pipelines of DL5045-2016 thermal power plants', 'design specifications of power pipelines of GB 507642012 power plants', 'guide rules of water inflow and cold steam of steam turbines of DL/T834-2003 thermal power plants', and 'recommended implementation rules of water damage prevention of steam turbines for ASME TDP-1-2013 power generation'.

S5, establishing a calculation model after optimization design, analyzing and calculating the hydraulic thermal characteristics of auxiliary equipment in the heater system, and comparing the flow distribution between each hydrophobic regulating valve pipeline and each bypass pipeline with the deviation of a hydraulic design value; the deviation processing formula of the hydraulic design values of each drain control valve pipeline and auxiliary equipment in the heater system is as follows:

in the formula, delta is a deviation calculation result; m is_JCalculating the flow of the pipeline of the drainage regulating valve; m is_SWater gauge for an auxiliary device in a heater systemCalculating the design flow;

and when the deviation calculation result is less than 1%, the optimization scheme is considered as a reasonable result.

And S6, adjusting the drift diameter of the bypass pipeline according to the deviation between the flow distribution between each drainage regulating valve pipeline and the bypass pipeline and the hydraulic design value, and finishing the optimization design. Referring to fig. 5, the calculation formula for selecting the pipe diameter of the bypass pipeline is as follows:

R₃＝F₁R₁+F₂R₂

wherein R is₁The diameter of the drainage pipeline; r₂The drift diameter of the drain regulating valve is adjusted; r₃The diameter of the bypass pipeline; f₁Weighting coefficients related to the diameter of the hydrophobic pipeline; f₂Weighting coefficients related to the drift diameter of the hydrophobic regulating valve;

wherein F₁、F₂Comprehensively determining and selecting after hydraulic calculation and analysis.

In S4, the bypass pipeline comprises a vertically extending straight pipe section, an arc transition section and a parallel straight pipe section;

vertically extending straight pipe section L₁The length calculation formula of (a) is as follows:

L₁＝f₁R₃

radius R of arc transition section₄The calculation formula of (2) is as follows:

R₄＝f₂R₃

parallel straight pipe section L₂The calculation formula of (2) is as follows:

L₂＝f₃R₃

wherein R is₃The diameter of the bypass pipeline; f. of₁Weighting coefficients associated with the vertically extending straight tube sections; f. of₂Weighting coefficients related to the middle arc transition section; f. of₃Weighting coefficients associated with the parallel straight tube sections;

wherein f is₁、f₂And f₃The selection of the method is to optimize the pipeline and the arc transition section molded line by a numerical simulation method with the minimum pressure drop as an optimization target and then determine.

S7, respectively calculating the work capacity reduction amount of the heater system and the device efficiency reduction value by adopting an equivalent enthalpy drop method, and finally evaluating the operation economy of the unit;

the method of calculating the reduction in capacity of the heater system is as follows:

when the high-pressure heater with the beta fraction drains water and enters a deaerator NO.m, the equivalent heat drop of new steam is increased as follows:

when the drained water is discharged into the condenser, the equivalent heat drop of the new steam is increased as follows:

the work loss of the switching drainage is the work difference of the two recovery modes, i.e.

ΔH＝H₁-H₂

In the formula: beta is the share of water entering the condenser, gamma is 1kg of heat release of water drainage, eta is the efficiency of the heater,in order to be the specific enthalpy of hydrophobicity,specific enthalpy of the hot well water outlet;

the calculation method of the device efficiency reduction value is as follows:

wherein, Δ H is the system work capacity reduction amount, and H is the work capacity before the heater system is optimized.

Referring to fig. 2, 3 and 4, a drain regulating valve 4 is arranged on a normal drain pipeline between the upper-level heater 1 and the lower-level heater 2, stop valves 3 are arranged at the upstream and the downstream of the drain regulating valve 4, and a bypass pipeline 5 is connected in parallel on the drain regulating valve 4.

According to the invention, by collecting and analyzing key data such as design data of the heater, a current water level set value of the heater, overhaul of the heater, emergency maintenance records, operation logs of a unit and the like, the technical current situations such as performance indexes of the current heater and load boundaries of the heater with poor drainage are mastered, a newly-added small-drift-diameter bypass pipeline is designed in a normal drainage regulating valve pipeline system of the heater according to a hydraulic calculation optimization result, the problem of large on-way resistance caused by improper selection of a drainage regulating valve or unreasonable pipeline arrangement is solved, the dangerous working condition that an emergency drainage valve is opened during low-load operation and high-quality working media are directly poured into a condenser is avoided, and further the aim of reducing the dangerous working condition that the high-quality working media are directly poured into the condenser is achievedThe purpose of improving the efficiency of the unit is reduced, and the method has very important significance for improving the safe and economic operation of the unit.