A method for constructing a multi-parameter steam source auxiliary steam header system

Abstract

The present invention discloses a method for constructing a multi-parameter steam source auxiliary steam manifold system. The present invention collects and analyzes key data such as the design, operation, maintenance and transformation data of the unit auxiliary steam system, grasps the technical status of the auxiliary steam system, and optimizes and designs auxiliary steam systems covering multi-parameter steam sources such as high and low pressure steam sources in the system according to the quantitatively approved user steam parameters. At the same time, the user energy level is divided, and the high and low energy level users are matched and connected to the auxiliary steam system of the corresponding energy level, so as to reduce the steam consumption under the condition of ensuring the production requirements, reduce the #imgabs0# loss and improve the system operation efficiency. The present invention can effectively solve the problem of energy cascade utilization matching the steam source point and the auxiliary steam user energy level, which is of great significance to improving the safe and economical operation of the unit.

Description

Technical Field

[0001] The invention belongs to the field of thermal power generation, and in particular relates to a method for constructing a multi-parameter steam source auxiliary steam header system. Background Art

[0002] The auxiliary steam system is a steam supply system for heating and protective steam related to the start-up, shutdown and normal operation of boilers, steam turbines and their auxiliary equipment in thermal power plants. The users and main functions of the auxiliary steam system are: start-up heating of equipment such as deaerators, boiler heaters, steam turbine cylinder interlayers and flange bolts; sealing of steam turbine shaft seal systems; heating, purging of fuel facilities and atomization of fuel nozzles; fire protection of pulverized coal preparation systems; antifreeze of instruments in open-air boilers; maintenance of boilers, deaerators and other equipment during short-term shutdown; heating and standby of deaerators during unit load shedding; heating and ventilation of plant buildings, heating of electrostatic precipitator ash hoppers and start-up heating of lower headers of natural circulation drum boilers, etc. The auxiliary steam system is an important subsystem involved in the start-up and safe production of thermal power plants.

[0003] At present, thermal power units are often in deep peak-shaving operation conditions. There is a common mismatch between the energy levels of auxiliary steam users and steam sources in the auxiliary steam system. In addition, there are many systems that directly reduce the temperature and pressure of high-quality steam and then provide it to users as the auxiliary steam manifold steam source, which will cause great energy losses.

[0004] Therefore, optimizing the existing auxiliary steam system of the unit and solving the problem of energy cascade utilization by matching the energy levels of the gas source point and the auxiliary steam users are of great significance to improving the economic efficiency of the unit operation. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a method for constructing a multi-parameter steam source auxiliary steam header system, which can optimize the existing auxiliary steam system of the unit, and add a multi-parameter steam source auxiliary steam header system by separating high- and low-pressure auxiliary steam users, and divide each user into energy levels, and respectively set up multi-parameter auxiliary steam systems covering high- and low-pressure steam sources, etc., connect high-energy-level users to the high-pressure auxiliary steam system, and connect low-energy-level users to the low-pressure auxiliary steam system, in order to solve the problem of energy cascade utilization matching the energy level of the gas source point and the auxiliary steam user, so as to reduce steam consumption under the condition of ensuring production requirements, and reduce The purpose of improving efficiency is achieved.

[0006] In order to achieve the above object, the present invention comprises the following steps:

[0007] Step 1: Analyze the steam source connection of the existing auxiliary steam system and the steam supply range of users according to the structure and assembly drawings of the auxiliary steam system unit;

[0008] Step 2: Based on the daily operation log of the unit and the data of the auxiliary steam system, understand the technical operation status of the auxiliary steam system and analyze the problems between the steam source of the auxiliary steam system and the start-up and shutdown of the unit;

[0009] Step 3: quantitatively verify the steam consumption of auxiliary steam system users, conduct statistics on steam energy level and consumption of auxiliary steam system users from the two aspects of the startup process and unit trial operation, and divide auxiliary steam system users into high-energy-level users and low-energy-level users;

[0010] Step 4: Based on the auxiliary steam requirements during unit startup and operation, the layout of the auxiliary steam system of the target unit is optimized on the basis of ensuring the safety and stability of the auxiliary steam system;

[0011] Step five, based on the steam usage parameter requirements of each auxiliary steam user, each user is divided into energy levels, covering the auxiliary steam systems of high-pressure gas source and low-pressure steam source respectively. The high-energy-level users are connected to the high-pressure auxiliary steam system, and the low-energy-level users are connected to the low-pressure auxiliary steam system.

[0012] In step one, the assembly drawings of the auxiliary steam system include the technical specification manual of the steam turbine, the technical specification manual of the boiler, the technical specification manual of the auxiliary equipment, the longitudinal sections of the high, medium and low pressure parts of the steam turbine, the thermal calculation sheet of the steam turbine, the heat balance diagram, the centralized control operation procedures and the maintenance procedures.

[0013] In step three, the startup process includes a flushing stage and an initial ignition stage, and the flushing stage includes a cold flushing stage and a hot flushing stage.

[0014] In step 5, the manifold parameters of the high-pressure auxiliary steam system are set to a pressure of 1.2 MPa and a temperature of 300°C, and the manifold parameters of the low-pressure auxiliary steam system are set to a pressure of 0.8 MPa and a temperature of 280°C.

[0015] In step five, the steam source of the manifold of the high-pressure auxiliary steam system is the auxiliary steam from the cold reheat steam and the auxiliary steam connecting pipe. When the parameters of the cold reheat steam do not meet the steam usage requirements, auxiliary steam is used. When the parameters of the cold reheat steam meet the switching conditions, it is switched to the cold reheat steam source.

[0016] In step five, the steam source of the manifold of the low-pressure auxiliary steam system is the auxiliary steam from the auxiliary steam connecting pipe and the low-five-stage steam extraction of the steam turbine. When the low-five-stage steam extraction of the steam turbine fails to meet the steam demand, the auxiliary steam is used.

[0017] In step 3, high-level users include boiler startup furnace bottom heating and condenser startup extraction;

[0018] Low-level users include air preheater soot blowing, deaerator and water tank heating, steam for turbine shaft seal system, dust collector ash hopper heating, boiler air heater, denitrification soot blowing and steam for small steam turbine.

[0019] After completing the energy level analysis in step five, conduct technical and economic analysis to evaluate the technical and economic feasibility of the auxiliary steam system.

[0020] Technical and economic analysis Based on the thermal balance diagram of the steam turbine, the steam source parameters of the high-pressure auxiliary steam system and the low-pressure auxiliary steam system were calculated when the unit was operating at 100% THA, 75% THA and 50% THA.

[0021] The technical and economic analysis includes quantitatively verifying the auxiliary steam consumption during the unit startup process, and using the equivalent enthalpy drop method to calculate the system's reduced work capacity, the change in heat absorption, and the reduction in device efficiency, and finally evaluating the unit's operating economy. The calculation method is as follows:

[0022] Work capacity reduction:

[0023] △H1=20 / G×(H 1z -H n +Q)

[0024] Among them, G is the main steam flow, H 1z is the specific enthalpy of cooling, H n is the exhaust enthalpy, Q is the heat absorbed by the reheated steam;

[0025] Changes in heat absorption:

[0026] △Q1=20 / G×Q

[0027] Reduced device efficiency:

[0028] △η1=[(H-ΔH1) / (Q2-ΔQ1)-η] / η×100%

[0029] Among them, H is the equivalent enthalpy drop of new steam, Q2 is the heat absorption of new steam, and η is the thermal efficiency of the turbine.

[0030] Compared with the prior art, the present invention collects and analyzes key data such as the design, operation, maintenance and transformation data of the auxiliary steam system of the unit, grasps the technical status of the auxiliary steam system, and optimizes the design of auxiliary steam systems covering multi-parameter steam sources such as high-pressure and low-pressure steam sources in the system according to the quantitatively approved user steam parameters. At the same time, the user energy level is divided, and the high- and low-level users are matched and connected to the auxiliary steam systems of the corresponding energy levels, thereby reducing steam consumption while ensuring production requirements and reducing The purpose of the invention is to improve the operating efficiency of the system. The invention can effectively solve the problem of energy cascade utilization matching the energy level of the steam source point and the auxiliary steam user, and has a very important significance for improving the safe and economical operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a flow chart of the present invention;

[0032] Figure 2 This is a diagram of the original auxiliary steam system of a power plant in the embodiment;

[0033] Figure 3 This is a diagram of the optimized auxiliary steam system of a power plant in the embodiment. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings.

[0035] See also Figure 1 , the present invention comprises the following steps:

[0036] Step 1: Analyze the existing auxiliary steam system steam source connection and user steam supply range based on the actual structure of the unit and the system assembly drawings.

[0037] Furthermore, the actual structure and system assembly drawings of the required units include: technical specifications for steam turbines, technical specifications for boilers, technical specifications for other auxiliary equipment (such as boiler pulverizing system, feed water pump, condensate pump, circulating water pump, condenser, cooling tower, main transformer, etc.), longitudinal sections of high, medium and low pressure parts of steam turbines, thermal calculations for steam turbines, thermal balance diagrams, centralized control operation procedures, maintenance procedures, etc.;

[0038] Step 2: Based on the daily operation log of the unit, the design data and operation data of the auxiliary steam system in the plant, grasp the technical operation status of the auxiliary steam system, and analyze the steam source and unit start-up and shutdown problems in the auxiliary steam system.

[0039] Step three, quantitatively verify the steam consumption of auxiliary steam system users, and conduct statistics on steam energy levels and consumption of auxiliary steam system users from two aspects: the startup process and unit trial operation.

[0040] Furthermore, the startup process includes a flushing stage, which is a cold flushing stage and a hot flushing stage. The startup process also includes an initial ignition stage.

[0041] Step 4: Based on the auxiliary steam demand during unit startup and operation, and on the basis of ensuring the safety and stability of the auxiliary steam system, an optimization plan is proposed for the layout of the auxiliary steam system of the target unit in reference to relevant standards of the power industry.

[0042] The relevant standards of the power industry referred to include: "DL / T834-2003 Guidelines for Preventing Water Ingress and Cold Steam in Steam Turbines of Thermal Power Plants", "ASME TDP-1-2013 Recommended Practice for Waterproofing Steam Turbines for Power Generation";

[0043] Step 5: Combined with the steam parameter requirements of each auxiliary steam user in step 3, each user is divided into energy levels, and multi-parameter auxiliary steam systems covering high and low pressure steam sources are set up respectively, where high energy level users are connected to the high pressure auxiliary steam system, and low energy level users are connected to the low pressure auxiliary steam system. And put forward adjustment suggestions for the operation mode of the optimized system.

[0044] Furthermore, the parameters of the high-pressure auxiliary steam system header are set at a pressure of 1.2MPa and a temperature of 300°C, and the parameters of the low-pressure auxiliary steam header are set at a pressure of 0.8MPa and a temperature of 280°C.

[0045] Furthermore, the steam source of the high-pressure auxiliary steam system manifold is the cold reheat steam and auxiliary steam from the auxiliary steam connecting pipe. When the cold reheat parameters cannot meet the steam requirements, temporary auxiliary steam is used. When the cold reheat steam parameters reach the switching conditions (not less than 1.4MPa), it is switched to the cold reheat steam source.

[0046] Furthermore, the steam source of the low-pressure auxiliary steam system manifold is the auxiliary steam from the auxiliary steam connecting pipe and the steam extraction from the lower fifth stage of the steam turbine. When the steam extraction from the lower fifth stage of the steam turbine cannot meet the steam demand, temporary auxiliary steam is used.

[0047] Furthermore, high-energy users connected to the high-pressure auxiliary steam system include: 1) boiler startup furnace bottom heating; 2) condenser startup exhaust.

[0048] Furthermore, the low-level users connected to the low-pressure auxiliary steam system include: 1) air preheater soot blowing; 2) deaerator and water tank heating; 3) steam for turbine shaft seal system; 4) dust collector ash hopper heating; 5) boiler heater; 6) denitrification soot blowing; 7)

[0049] Steam for small steam turbine.

[0050] Step 6. After the system design is completed, conduct technical and economic analysis to comprehensively evaluate the technical and economic feasibility of the optimized auxiliary steam system.

[0051] Furthermore, the technical analysis was carried out based on the thermal balance diagram of the steam turbine to calculate the steam source parameters of the high and low pressure auxiliary steam systems when the unit was operating at 100% THA, 75% THA and 50% THA.

[0052] Furthermore, the economic analysis quantitatively verifies the auxiliary steam consumption during the unit startup process, and uses the equivalent enthalpy drop method to calculate the system's reduced working capacity, the change in heat absorption and the reduction in device efficiency, and finally evaluates the unit's operating economy.

[0053] 1) Decrease in work capacity

[0054] △H1=20 / G×(H 1z -H n+Q)(1)

[0055] Where: G is the main steam flow, which is the main steam flow designed for rated conditions; H 1z is the specific enthalpy of cooling, kJ / kg; H n is the exhaust enthalpy, kJ / kg, taking the design value of THA condition; Q is the heat absorption of reheat steam, kJ / kg.

[0056] 2) Changes in heat absorption

[0057] △Q1=20 / G×Q (2)

[0058] 3) Reduced device efficiency

[0059] △η1=[(H-ΔH1) / (Q2-ΔQ1)-η] / η×100% (3)

[0060] Where: H is the equivalent enthalpy drop of new steam, kJ / kg; Q2 is the heat absorption of new steam, kJ / kg; η is the thermal efficiency of the turbine, which is 0.44.

[0061] See also Figure 2 , an embodiment of the present invention is given by taking a certain power plant as an example.

[0062] The steam turbine type of a certain power plant is: subcritical, single-intermediate reheat, single-shaft, three-cylinder, double-exhaust, impulse condensing.

[0063] The original auxiliary steam system of the unit consists of a steam supply system, an auxiliary steam header, auxiliary steam users and an auxiliary steam system safety valve. An auxiliary steam main pipe is set in the whole plant, and each unit is equipped with an auxiliary steam header. The auxiliary steam header pressure is set to 1.2MPa and the temperature is 300℃. Among them, the cold reheat steam supply pressure is 4.17MPa, and the cold reheat steam temperature is 326℃. The auxiliary steam header pressure operating pressure is 1.2MPa, and the auxiliary steam header steam temperature is 300℃. The set pressures of the three safety valves of the auxiliary steam header are: No. 1 1.4MPa, No. 2 1.4MPa, and No. 3 1.4MPa. When the auxiliary steam system is running, when the cold reheat steam pressure is not less than 1.4MPa, the cold reheat steam will supply steam to the auxiliary steam header, otherwise the temporary machine will supply steam to the auxiliary steam header. The auxiliary steam headers of units 1 and 2 in the original system are connected to the auxiliary steam headers through auxiliary steam connecting pipes. They are standby for each other. The auxiliary steam systems can be operated in parallel or independently by opening and closing the auxiliary steam connecting valves and the main pipe sectioning valves. When the units are operated independently, the auxiliary steam headers are supplied with steam from the unit's cold reheat steam.

[0064] The main function of the auxiliary steam header is to provide steam for unit startup and steam for related equipment and desulfurization system of the unit during normal operation. The steam supply objects are:

[0065] 1) Steam turbine shaft seal;

[0066] 2) Heating the water tank;

[0067] 3) Start the vacuum pump;

[0068] 4) Boiler heater

[0069] 5) Heating of electrostatic precipitator hopper;

[0070] 6) Steam for small steam engines;

[0071] 7) Air preheater auxiliary steam soot blowing;

[0072] 8) Denitrification soot blowing;

[0073] 9) WGGH heat medium water auxiliary steam heater;

[0074] 10) WGGH smoke cooler soot blowing.

[0075] The unit starts and stops frequently. During the startup process, the main users of auxiliary steam are steam for deaerator, continuous soot blowing of air preheater, steam for heating boiler bottom and condenser startup extraction. During the startup process, the steam for deaerator, continuous soot blowing of air preheater and heating of boiler bottom last for a long time, so the auxiliary steam consumption is large. When the annual start-up and shutdown times of the unit increase, the auxiliary steam consumption will also increase.

[0076] Through the analysis of auxiliary steam consumption in three conditions: cold flushing, ignition cleaning and cold start, the auxiliary steam consumption is statistically analyzed. The statistical situation is shown in Table 1.

[0077] The main user of auxiliary steam in the cold flushing stage is deaerator heating. The cold flushing water temperature is generally 20-70℃, and the feed water flow rate is 150-250t / h. In this stage, the deaerator is the main auxiliary steam user for heating, and the actual steam consumption is about 15t / h.

[0078] During the hot flushing stage, the boiler is ready for ignition, and the boiler water is recovered to the deaerator. The main auxiliary steam users are in the following order: the plasma heater consumes 7.8 t / h of steam per month and lasts for 3 hours. The primary hot air temperature can be increased to 150°C, which can reduce the auxiliary steam consumption to 5 t / h; the air preheater continuously soot blows about 5 t / h; and the shaft seal is put into use at about 2.5 t / h.

[0079] After the boiler is ignited, it enters the hot cleaning stage. The boiler plant design requires that the flow rate through the water-cooled wall during the hot cleaning stage should not be less than 30% BMCR. In actual operation, in order to ensure combustion at the initial stage of ignition, the primary air temperature must be increased. Steam for the heater, shaft seal, and air preheater soot blowing must be ensured at the initial stage of ignition, and steam for the deaerator should be appropriately reduced, which is the same as the hot flushing operation. At the same time, during the cold start, the flushing time is extended, and the water-cooled wall temperature is gradually increased. Generally, after ignition for 3 hours, the heater can gradually reduce the steam intake, gradually increase the auxiliary steam pressure, and improve the air preheater soot blowing effect and feed water heating effect.

[0080] According to the characteristics of the boiler, the actual feed water flow rate ranges from 220 to 320 t / h at the initial stage of ignition. It takes about 5 hours from ignition to start-up parameters. During this period, the plasma heater has switched to hot primary air and the heater steam consumption has stopped. The auxiliary steam users are air preheater soot blowing, deaerator heating, and shaft sealing. In actual operation, 20 t / h of auxiliary steam consumption can fully meet the steam demand.

[0081] Table 1 Statistics of original auxiliary steam consumption

[0082]

[0083] See also Figure 3 Taking a certain power plant as an example, the method of the present invention was used for optimization design. According to the auxiliary steam demand during unit startup and operation, the layout and operation mode of the auxiliary steam system were optimized on the basis of ensuring the safety and stability of the auxiliary steam system.

[0084] Firstly, according to the auxiliary steam system connection and user needs, the steam usage parameters of each auxiliary steam user are counted, see Table 2 for details.

[0085] Table 2 Statistics of steam parameters used by auxiliary steam users

[0086]

[0087] In the design of the new auxiliary steam system, the steam source of the high-pressure auxiliary steam header is set to be the cold reheat steam and the auxiliary steam from the auxiliary steam connecting pipe, and the steam source of the low-pressure auxiliary steam header is the auxiliary steam from the auxiliary steam connecting pipe and the 5th stage extraction steam. The steam sources of the auxiliary steam headers are mutually backup.

[0088] Combined with the steam parameter requirements of each auxiliary steam user in Table 2, the auxiliary steam users are treated differently according to their steam parameters, and high and low auxiliary steam systems are set up. High parameter users are connected to the high-pressure auxiliary steam system, and low parameter users are connected to the low-pressure auxiliary steam system.

[0089] The parameters of the high-pressure auxiliary steam header are set to 1.2MPa, 300℃, and the parameters of the low-pressure auxiliary steam header are set to 0.8MPa, 280℃. The steam source of the high-pressure auxiliary steam header is the auxiliary steam from the cold reheat steam and the auxiliary steam from the auxiliary steam connecting pipe. When the cold reheat parameters cannot meet the steam requirements, temporary auxiliary steam is used. When the cold reheat steam parameters reach the switching conditions (not less than 1.4MPa), the cold reheat steam source is switched. The steam source of the low-pressure auxiliary steam header is the auxiliary steam from the auxiliary steam connecting pipe and the switching of the 5-stage extraction steam is the same as the steam source switching method of the high-pressure auxiliary steam header.

[0090] Auxiliary steam header steam sources are mutually backup

[0091] Based on this, users of high parameter auxiliary steam header are:

[0092] 1) The boiler starts heating the furnace bottom;

[0093] 2) Start the condenser to pump air.

[0094] Users of low-parameter auxiliary steam headers are:

[0095] 1) Air preheater soot blowing;

[0096] 2) Deaerator and water tank heating;

[0097] 3) Steam for turbine shaft seal system;

[0098] 4) Dust collector hopper heating;

[0099] 5) Boiler heater;

[0100] 6) Denitrification soot blowing;

[0101] 7) Steam for small steam turbines.

[0102] After the system design is completed, an economic analysis of the unit is carried out.

[0103] The benefits generated during the startup process of the new design system are the difference in the impact on the unit economy caused by using low auxiliary header steam supply and the original system using cold reheat steam supply.

[0104] According to the isentropic enthalpy drop calculation method, the results of the unit operation economic analysis are summarized in Table 3, where the standard coal price is taken as 700 yuan / t including tax when converting costs. It can be seen that under THA conditions, according to the isentropic enthalpy drop calculation method, in the original auxiliary steam system, the steam work is reduced by 23.71 kJ / kg, the heat absorption changes by 9.90 kJ / kg, and the unit efficiency is reduced by 1.59 percentage points; in the optimized auxiliary steam system, the steam work is reduced by 16.55 kJ / kg, and the unit efficiency is reduced by 1.36 percentage points. Compared with the original auxiliary steam system, the optimized auxiliary steam system is calculated to reduce the annual coal consumption by 1,167.43 tons, and the converted income is 817,200 yuan / year;

[0105] Through the implementation of the present invention, the problem of energy cascade utilization matching the energy level of the steam source point and the auxiliary steam user can be effectively solved, and the steam consumption can be reduced under the condition of ensuring production requirements. The purpose of reducing losses and improving system operating efficiency is of great significance to improving the safe and economical operation of the unit.

[0106] Table 3 Economic analysis of the optimized auxiliary steam system operation

[0107]

[0108]

Claims

1. A method for constructing a multi-parameter steam source auxiliary steam header system, characterized in that: The following steps are involved: Step 1: Analyze the existing auxiliary steam system steam source connection and user steam supply range according to the structure and assembly drawings of the auxiliary steam system unit; the assembly drawings of the auxiliary steam system include the technical specifications of the steam turbine, the technical specifications of the boiler, the technical specifications of the auxiliary equipment, the longitudinal sections of the high, medium and low pressure parts of the steam turbine, the thermal calculation of the steam turbine, the heat balance diagram, the centralized control operation procedures and the maintenance procedures; Step 2: Based on the daily operation log of the unit and the data of the auxiliary steam system, understand the technical operation status of the auxiliary steam system and analyze the problems between the steam source of the auxiliary steam system and the start-up and shutdown of the unit; Step 3: quantitatively verify the steam consumption of auxiliary steam system users, conduct statistics on steam energy level and consumption of auxiliary steam system users from the two aspects of the startup process and unit trial operation, and divide auxiliary steam system users into high-energy level users and low-energy level users; high-energy level users include boiler startup furnace bottom heating and condenser startup extraction; Low-level users include air preheater soot blowing, deaerator and water tank heating, steam for turbine shaft seal system, dust collector ash hopper heating, boiler air heater, denitrification soot blowing and steam for small steam turbines; Step 4: Based on the auxiliary steam requirements during unit startup and operation, the layout of the auxiliary steam system of the target unit is optimized on the basis of ensuring the safety and stability of the auxiliary steam system; Step 5. Combined with the steam parameter requirements of each auxiliary steam user, each user is divided into energy levels, covering auxiliary steam systems of high-pressure gas source and low-pressure steam source respectively. High-energy users are connected to the high-pressure auxiliary steam system, and low-energy users are connected to the low-pressure auxiliary steam system. The header steam source of the high-pressure auxiliary steam system is cold reheat steam and auxiliary steam from the auxiliary steam connecting pipe. When the cold reheat steam parameters do not meet the steam requirements, auxiliary steam is used. When the cold reheat steam parameters meet the switching conditions, it is switched to the cold reheat steam source. The header parameters of the high-pressure auxiliary steam system are set to a pressure of 1.2MPa and a temperature of 300℃, and the header parameters of the low-pressure auxiliary steam system are set to a pressure of 0.8MPa and a temperature of 280℃. After completing the energy level analysis in step five, conduct technical and economic analysis to evaluate the technical and economic feasibility of the auxiliary steam system.

2. A method for constructing a multi-parameter steam source auxiliary steam header system according to claim 1, characterized in that: In step three, the startup process includes a flushing stage and an initial ignition stage, and the flushing stage includes a cold flushing stage and a hot flushing stage.

3. A method for constructing a multi-parameter steam source auxiliary steam header system according to claim 1, characterized in that: In step five, the steam source of the manifold of the low-pressure auxiliary steam system is the auxiliary steam from the auxiliary steam connecting pipe and the low-five-stage steam extraction of the steam turbine. When the low-five-stage steam extraction of the steam turbine fails to meet the steam demand, the auxiliary steam is used.

4. A method for constructing a multi-parameter steam source auxiliary steam header system according to claim 1, characterized in that: Technical and economic analysis Based on the thermal balance diagram of the steam turbine, the steam source parameters of the high-pressure auxiliary steam system and the low-pressure auxiliary steam system were calculated when the unit was operating at 100% THA, 75% THA and 50% THA.

5. A method for constructing a multi-parameter steam source auxiliary steam header system according to claim 1, characterized in that The technical and economic analysis includes quantitatively verifying the auxiliary steam consumption during the unit startup process, and using the equivalent enthalpy drop method to calculate the system's reduced work capacity, the change in heat absorption, and the reduction in device efficiency, and finally evaluating the unit's operating economy. The calculation method is as follows: Work capacity reduction: △H1=20 / G×(H 1z - H n +Q) Among them, G is the main steam flow, H 1z is the specific enthalpy of cooling, H n is the exhaust enthalpy, Q is the heat absorbed by the reheated steam; Changes in heat absorption: △Q1=20 / G×Q Reduced device efficiency: △η1=[(H-ΔH1) / (Q2-ΔQ1)-η] / η×100% Among them, H is the equivalent enthalpy drop of new steam, Q2 is the heat absorption of new steam, and η is the thermal efficiency of the turbine.

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