A waste heat and energy power generation system for steel enterprises

Abstract

This invention discloses a waste heat and waste energy power generation system for steel enterprises, including a boiler (1), a steam turbine generator (2), a condensing unit (3), a main steam header (4), a low-temperature reheat steam header (5), a high-temperature reheat steam header (6), and a main feedwater header (8). The boiler (1) includes a gas boiler (11) and a waste heat boiler (12), and the steam turbine generator (2) includes a high-pressure cylinder (21) and a low-pressure cylinder (22). The waste heat and waste energy power generation system for steel enterprises can balance the fluctuations in power generation load caused by fluctuations in gas or intermittent waste heat resources, and achieve a dynamic balance between gas, waste heat, and power generation load. It can effectively prevent damage to the units from low-load operation and improve the overall power generation efficiency of multiple units.

Description

Technical Field

[0001] This invention relates to the field of gas power generation and waste heat power generation technology, specifically a waste heat and waste energy power generation system for steel enterprises. Background Technology

[0002] Steel production generates a large amount of surplus energy, such as waste heat and secondary energy (blast furnace gas, converter gas, coke oven gas). Steel companies build their own power plants to generate electricity using waste heat, waste pressure, and secondary energy to power steel production and improve the company's operating efficiency. In recent years, the parameters of generator units in steel plant self-owned power plants have been improved in stages, successively going through medium temperature and medium pressure (3.43MPa / 435℃) or lower, with a power generation efficiency of ≤25%; high temperature and high pressure (8.83MPa / 535℃), with a power generation efficiency of about 29%-31%; high temperature and ultra-high pressure (13.2MPa / 535℃), with a power generation efficiency of about 35%-38%; ultra-high temperature and ultra-high pressure (13.2MPa / 566℃), with a power generation efficiency of about 37%-39%; currently, ultra-high temperature subcritical technology is being gradually applied to steel plant self-owned power plants, with technical parameters improved to 17.5MPa / 571℃ and power generation efficiency improved to 40%-41%, which is about 30.5% higher than that of high temperature and high pressure technology.

[0003] In steel enterprises, waste heat power generation and gas power generation are usually two independent units. These units differ in operation and parameters, and their turbines are difficult to match, leading to separate construction and operation, requiring larger spaces and more personnel for maintenance. Blast furnace ironmaking and converter steelmaking units in steel enterprises generate large amounts of low-calorific-value gas. However, the production of this gas fluctuates, causing fluctuations in the steam produced by the gas boilers. When steam supply is insufficient, the turbine generator units often operate at low loads or stop, reducing power generation efficiency, causing wear and tear on the units, and increasing operating costs. In the coking process, coke ovens are divided into those that recover coke oven gas and those that do not. In recent years, coke ovens without coke oven gas recovery have been increasingly adopted by users due to their unique advantages and are also known as clean heat recovery coke ovens. Clean heat recovery coke ovens no longer recover coke oven gas, but can generate high-temperature flue gas of about 1100℃. The high-temperature flue gas can generate high-parameter steam through waste heat boilers. However, due to the limited steam volume, there are only a few high-temperature and ultra-high-pressure units used in steel plants. Most of them are still high-temperature and high-pressure units or even medium-temperature and medium-pressure units, which have low power generation efficiency and cannot make efficient use of waste heat resources. Summary of the Invention

[0004] In order to integrate waste heat power generation and coal gas power generation, the present invention provides a waste heat and waste energy power generation system for steel enterprises. The waste heat and waste energy power generation system for steel enterprises can balance the fluctuation of power generation load caused by coal gas fluctuations or the intermittency of waste heat resources, realize the dynamic balance of coal gas, waste heat and power generation load, effectively prevent damage to the unit from low load operation, and improve the comprehensive power generation efficiency of multiple units.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A waste heat and energy power generation system for steel enterprises includes a boiler, a steam turbine generator, a condensing unit, a main steam header, a low-temperature reheat steam header, a high-temperature reheat steam header, and a main feedwater header. The boiler includes a gas boiler and a waste heat boiler. The steam turbine generator includes a high-pressure cylinder and a low-pressure cylinder. The main steam in the main steam header can enter the high-pressure cylinder of the steam turbine generator. The low-temperature reheat steam discharged from the high-pressure cylinder can enter the low-temperature reheat steam header. The low-temperature reheat steam in the low-temperature reheat steam header can enter the boiler and be heated into high-temperature reheat steam, which then enters the high-temperature reheat steam header. The high-temperature reheat steam in the high-temperature reheat steam header can enter the low-pressure cylinder of the steam turbine generator. The working steam discharged from the low-pressure cylinder can enter the condensing unit to form condensate, which then enters the main feedwater header. The condensate in the main feedwater header can enter the boiler and be heated into the main steam, which then enters the main steam header.

[0007] The gas boiler is an ultra-high temperature subcritical gas boiler, the waste heat boiler is an ultra-high temperature subcritical waste heat boiler, the waste heat boiler includes coke oven waste heat boiler and dry quenching coke waste heat boiler, and the steam turbine generator is an ultra-high temperature subcritical steam turbine generator.

[0008] The waste heat and energy power generation system of the steel enterprise includes one gas boiler, four coke oven waste heat boilers, one dry quenching coke waste heat boiler, two steam turbine generators, and two condensing units.

[0009] The main steam header is connected to the inlet of the high-pressure cylinder through the first branch pipe of the main steam header, and the low-temperature reheat steam header is connected to the outlet of the high-pressure cylinder through the first branch pipe of the low-temperature reheat steam header.

[0010] The boiler contains a reheater. The low-temperature reheat steam header is connected to the inlet of the reheater through the second low-temperature reheat steam branch pipe, and the high-temperature reheat steam header is connected to the outlet of the reheater through the first high-temperature reheat steam branch pipe.

[0011] The high-temperature reheat steam header is also connected to the inlet of the low-pressure cylinder via the second high-temperature reheat steam branch pipe. The inlet of the condensing unit is connected to the outlet of the low-pressure cylinder via the steam discharge branch pipe. The outlet of the condensing unit is connected to the main feedwater header via the condensate pipeline.

[0012] The waste heat and energy power generation system of the steel enterprise also includes a low-pressure bypass steam main pipe and a low-pressure bypass branch. A bypass valve is provided on the low-pressure bypass branch. An electric regulating valve is provided on the first branch of high-temperature reheat steam. The inlet end of the low-pressure bypass branch is connected to the first branch of high-temperature reheat steam. The inlet end of the low-pressure bypass branch is located between the electric regulating valve and the reheater. The outlet end of the low-pressure bypass branch is connected to the low-pressure bypass steam main pipe.

[0013] The condensing unit is a condenser, which contains a three-stage water spray desuperheater. The low-pressure bypass steam header is connected to the three-stage water spray desuperheater through the low-pressure bypass steam branch pipe. The condensate pipeline is equipped with a condensate pump, a deaerator, a deaerator water tank, and a feedwater pump in sequence.

[0014] The boiler contains an economizer, a water-cooled wall, and a superheater connected in sequence. The main feedwater header is connected to the economizer through a main feedwater branch pipe. A flow distributor is installed on the main feedwater branch pipe. The main steam header is connected to the superheater through a main steam second branch pipe. An electric regulating valve is installed on the main steam second branch pipe.

[0015] The waste heat and energy power generation system of the steel enterprise also includes a high-pressure bypass branch. A bypass valve is installed on the high-pressure bypass branch. The inlet end of the high-pressure bypass branch is connected to the second branch of the main steam pipe. The inlet end of the high-pressure bypass branch is located between the main steam header and the electric regulating valve. The outlet end of the high-pressure bypass branch is connected to the second branch of the low-temperature reheat steam pipe. A flow distributor is installed on the second branch of the low-temperature reheat steam pipe. The outlet end of the high-pressure bypass branch is located between the low-temperature reheat steam header and the flow distributor.

[0016] The beneficial effects of the present invention are: the waste heat and waste energy power generation system of the steel enterprise can balance the power generation load fluctuation caused by gas fluctuation or intermittent waste heat resources, realize the dynamic balance of gas, waste heat and power generation load, effectively prevent damage to the unit under low load operation, and improve the comprehensive power generation efficiency of multiple units. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a schematic diagram of the waste heat and energy power generation system for steel enterprises described in this invention.

[0019] Figure 2 yes Figure 1 A schematic diagram of the left side of the middle section.

[0020] Figure 3 This is a schematic diagram of the reheater section inside a gas boiler.

[0021] Figure 4This is a schematic diagram of the economizer, water-cooled wall, and superheater in a gas boiler.

[0022] Figure 5 This is a schematic diagram of the steam turbine generator section.

[0023] The annotations in the attached figures are explained as follows:

[0024] 1. Boiler; 2. Steam turbine generator; 3. Condensation unit; 4. Main steam header; 5. Low-temperature reheat steam header; 6. High-temperature reheat steam header; 7. Low-pressure bypass steam header; 8. Main feedwater header;

[0025] 11. Gas boiler; 12. Waste heat boiler;

[0026] 21. High-pressure cylinder; 22. Low-pressure cylinder;

[0027] 31. Steam exhaust branch pipe; 32. Condensate pipeline; 33. Three-stage spray desuperheater;

[0028] 41. Main steam first branch pipe; 42. Main steam second branch pipe; 43. High-pressure bypass branch;

[0029] 51. Low-temperature reheat steam first branch pipe; 52. Low-temperature reheat steam second branch pipe;

[0030] 61. First branch pipe of high-temperature reheat steam; 62. Second branch pipe of high-temperature reheat steam;

[0031] 71. Low-pressure bypass branch; 72. Low-pressure bypass steam branch;

[0032] 81. Main water supply branch pipe;

[0033] 91. Bypass valve; 92. Electric regulating valve; 93. Flow distributor;

[0034] 101. Reheater; 102. Economizer; 103. Water-cooled wall; 104. Superheater;

[0035] 121. Coke oven waste heat boiler; 122. Dry quenching coke waste heat boiler;

[0036] 321. Condensate pump; 322. Deaerator and deaerator tank; 323. Feed water pump. Detailed Implementation

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] A waste heat and energy power generation system for an iron and steel enterprise includes a boiler 1, a steam turbine generator 2, a condensing unit 3, a main steam header 4, a low-temperature reheat steam header 5, a high-temperature reheat steam header 6, and a main feedwater header 8. The boiler 1 includes a gas boiler 11 and a waste heat boiler 12. The steam turbine generator 2 includes a high-pressure cylinder 21 and a low-pressure cylinder 22. The main steam in the main steam header 4 can enter the high-pressure cylinder 21 of the steam turbine generator 2 to perform work, and the low-temperature reheat steam discharged from the high-pressure cylinder 21 can enter the low-temperature reheat steam header 5. The low-temperature reheat steam in the low-temperature reheat steam header 5 can enter the boiler 1, be heated into high-temperature reheat steam, and then enter the high-temperature reheat steam header 6. The high-temperature reheat steam in the high-temperature reheat steam header 6 can enter the low-pressure cylinder 22 of the turbine generator 2 to perform work. The steam discharged from the low-pressure cylinder 22 can enter the condensing device 3 to form condensate and then enter the main feedwater header 8. The condensate in the main feedwater header 8 can enter the boiler 1, be heated into the main steam, and then enter the main steam header 4. Figures 1 to 5 As shown.

[0039] The waste heat and energy power generation system of the steel enterprise includes a gas boiler 11 and a waste heat boiler 12, which are integrated together. The gas boiler 11 can be an existing ultra-high temperature subcritical gas boiler, and the waste heat boiler 12 can be an existing ultra-high temperature subcritical waste heat boiler. The technical parameters of the ultra-high temperature subcritical waste heat boiler are above 17.5 MPa / 571℃, and the power generation efficiency reaches above 40%-41%. The waste heat boiler 12 includes a coke oven waste heat boiler 121 and a dry quenching coke waste heat boiler 122. The steam turbine generator 2 can be an existing ultra-high temperature subcritical steam turbine generator. Boiler 1 can be either a gas boiler 11 or a waste heat boiler 12 (such as a coke oven waste heat boiler 121 or a dry quenching coke waste heat boiler 122). Figure 1 As shown.

[0040] The gas source for the gas boiler 11 comes from blast furnace gas, converter gas, and coke oven gas. The gas boiler 11 can be connected to blast furnace gas, converter gas, and coke oven gas. The heat source for the coke oven waste heat boiler 121 comes from the coke oven and is connected to the coke oven. The heat source for the dry quenching waste heat boiler 122 comes from the dry quenching coke and is connected to the dry quenching device. The waste heat and energy power generation system of the steel enterprise may include one gas boiler 11, four coke oven waste heat boilers 121, one dry quenching waste heat boiler 122, two steam turbine generators 2, and two condensing devices 3.

[0041] In this embodiment, the main steam header 4 is connected to the inlet of the high-pressure cylinder 21 via the first main steam branch pipe 41, and the low-temperature reheat steam header 5 is connected to the outlet of the high-pressure cylinder 21 via the first low-temperature reheat steam branch pipe 51. The boiler 1 includes a reheater 101. The low-temperature reheat steam header 5 is connected to the inlet of the reheater 101 via the second low-temperature reheat steam branch pipe 52, and the high-temperature reheat steam header 6 is connected to the outlet of the reheater 101 via the first high-temperature reheat steam branch pipe 61, as shown below. Figures 1 to 5 As shown.

[0042] In this embodiment, the high-temperature reheat steam header 6 is also connected to the inlet of the low-pressure cylinder 22 via the high-temperature reheat steam second branch pipe 62. The inlet of the condensing device 3 is connected to the outlet of the low-pressure cylinder 22 via the steam discharge branch pipe 31, and the outlet of the condensing device 3 is connected to the main feedwater header 8 via the condensate pipeline 32. Each boiler 1 (which can be a gas boiler 11, a coke oven waste heat boiler 121, or a dry quenching coke waste heat boiler 122) can be connected to other devices or components in the same way, and each boiler 1 is connected in parallel. Each steam turbine generator 2 can be connected to other devices or components in the same way, and each steam turbine generator 2 is connected in parallel.

[0043] In this embodiment, the waste heat and energy power generation system of the steel enterprise also includes a low-pressure bypass steam main pipe 7 and a low-pressure bypass branch pipe 71. A bypass valve 91 is provided on the low-pressure bypass branch pipe 71, and an electric regulating valve 92 is provided on the high-temperature reheat steam first branch pipe 61. The inlet end of the low-pressure bypass branch pipe 71 is connected to the high-temperature reheat steam first branch pipe 61. The inlet end of the low-pressure bypass branch pipe 71 is located between the electric regulating valve 92 and the reheater 101. The outlet end of the low-pressure bypass branch pipe 71 is connected to the low-pressure bypass steam main pipe 7.

[0044] In this embodiment, the condensing device 3 is a condenser, which includes a three-stage water spray desuperheater 33. The low-pressure bypass steam header 7 is connected to the three-stage water spray desuperheater 33 via a low-pressure bypass steam branch pipe 72. The steam in the low-pressure bypass steam header 7 can enter the condensing device 3 through the low-pressure bypass steam branch pipe 72 and be converted into condensate. The condensate pipeline 32 is sequentially equipped with a condensate pump 321, a deaerator and a deaerator water tank 322, and a feedwater pump 323, as follows: Figure 5 As shown.

[0045] In this embodiment, the boiler 1 includes an economizer 102, a water-cooled wall 103, and a superheater 104 connected in sequence. The main feedwater header 8 is connected to the economizer 102 through the main feedwater branch pipe 81. A flow distributor 93 is provided on the main feedwater branch pipe 81. The main steam header 4 is connected to the superheater 104 through the main steam second branch pipe 42. An electric regulating valve 92 is provided on the main steam second branch pipe 42.

[0046] In this embodiment, the waste heat and energy power generation system of the steel enterprise also includes a high-pressure bypass branch 43. A bypass valve 91 is installed on the high-pressure bypass branch 43. The inlet end of the high-pressure bypass branch 43 is connected to the second main steam branch pipe 42, located between the main steam header 4 and the electric regulating valve 92. The outlet end of the high-pressure bypass branch 43 is connected to the second low-temperature reheat steam branch pipe 52, which is equipped with a flow distributor 93. The outlet end of the high-pressure bypass branch 43 is located between the low-temperature reheat steam header 5 and the flow distributor 93. Additionally, electric regulating valves 92 are installed on the main steam header 4, the low-temperature reheat steam header 5, the high-temperature reheat steam header 6, the low-pressure bypass steam header 7, and the main feedwater header 8.

[0047] The above example includes one gas boiler 11, four coke oven waste heat boilers 121, one dry quenching coke waste heat boiler 122, and two steam turbine generators 2, which are merely exemplary embodiments. The system is not necessarily fixed; it could be one gas boiler 11 and one waste heat boiler 12 paired with one steam turbine generator 2, or one gas boiler 11 and multiple waste heat boilers 12 paired with multiple steam turbine generators 2. Various changes and modifications can be made without departing from the scope defined in the claims. The layout optimization can comprehensively consider the utilization of surplus gas power generation, coke oven flue gas waste heat, dry quenching coke waste heat power generation, and other waste energy and waste heat resources, as well as the plant's self-contained power station.

[0048] The following describes the working process of the waste heat and energy power generation system in the steel enterprise.

[0049] The main steam (571℃, 17.5MPa) generated by the superheater 104 of the gas boiler 11 (ultra-high temperature subcritical gas boiler) and the waste heat boiler 12 is connected to the main steam header 4. The main steam in the main steam header 4 enters the inlet of the high-pressure cylinder 21 through the first branch pipe 41 of the main steam. After the main steam does work in the high-pressure cylinder 21, it discharges low-temperature reheat steam (373℃, 4.31MPa) and enters the low-temperature reheat steam header 5. The low-temperature reheat steam header 5 is connected to the inlet of the reheater 101 of the boiler. The low-temperature reheat steam enters the reheater 101 of the boiler and is heated. The high-temperature reheat steam (571℃, 4.31MPa) generated by the boiler's reheater 101 enters the high-temperature reheat steam header 6 through the first high-temperature reheat steam branch pipe 61. The first high-temperature reheat steam branch pipe 61 is connected to a low-pressure bypass branch pipe 71. The low-pressure bypass branch pipe 71 of each boiler is connected to the low-pressure bypass steam header 7. The low-pressure bypass steam header 7 is connected to the three-stage spray desuperheater 33 of the condenser through the low-pressure bypass steam branch pipe 72. The high-temperature reheat steam header 6 enters the inlet of the low-pressure cylinder 22 through the second high-temperature reheat steam branch pipe 62. The high-temperature reheat steam expands and does work in the turbine generator 2, and is condensed into water in the condenser after heat exchange and cooling. After being pressurized by the condensate pump 321 and further heated by the low-pressure heater, the condensate enters the deaerator and deoxygenated water tank 322. The deaerator heats and deoxygenates the condensate, and then the condensate enters the deoxygenated water tank. The deaerated water tank outlet enters the feedwater pump 323 for pressurization, and after heat exchange and temperature increase by the high-pressure heater, it enters the main feedwater header 8. The main feedwater header 8 is connected to the inlet of the economizer 102 of the boiler through the main feedwater branch pipe 81. The main feedwater enters the economizer 102 of the boiler, then passes through the water-cooled wall 103 inside the boiler for heat exchange and temperature increase and vaporization, and is then discharged from the superheater 104 of the boiler, thus forming a steam-water cycle. Figures 1 to 5 As shown.

[0050] The waste heat and energy power generation system of the steel enterprise connects the gas boiler 11 and the waste heat boiler 12 to the high-capacity, high-parameter steam turbine generator 2 through a main pipe and a branch pipe, respectively. The main pipe with an electric regulating valve 92 connects the boiler side and the turbine side, which can adjust the gas intake of the steam turbine generator 2 in real time to maintain high power operation and balance the load of the gas boiler 11 and the waste heat boiler 12 in real time to adapt to the fluctuation of surplus gas.

[0051] Electric regulating valves 92 are installed at both ends of the branch pipes on the main steam header. These valves can balance the distribution of high-parameter steam generated from the waste heat boiler 12 and the gas boiler 11 into the high-pressure cylinder 21 of each steam turbine generator 2. When the gas fluctuates, the amount of gas entering the gas boiler 11 for combustion increases or decreases, the amount of high-parameter steam generated by the gas boiler 11 increases or decreases, and the amount of steam entering the main steam header 4 from the gas boiler 11 increases or decreases. If the amount of steam generated by the waste heat boiler 12 is less or more, the electric regulating valves 92 on the header can be used to control the flow rate into the high-pressure cylinder 21 of the No. 1 or No. 2 steam turbine generator 2, thereby ensuring that both steam turbine generators 2 are in a high-load state and operate efficiently. After the high-parameter steam drives the high-pressure cylinder 21 to do work, it is converted into low-temperature reheat steam and merged into the low-temperature reheat steam header 5 from the outlet of the high-pressure cylinder 21. The low-temperature reheat steam must also match the real-time main steam flow rate. The amount of steam entering the reheater 101 of the waste heat boiler 12 and the gas boiler 11 is controlled by the flow distributor 93 on the second branch pipe 52 of the low-temperature reheat steam. The high-temperature reheat steam generated by the boiler's reheater 101 is incorporated into the high-temperature reheat steam header 6. The flow rate into the low-pressure cylinder 22 of turbine generator 1 or 2 is controlled by the electric regulating valve 92, thereby ensuring that both turbine generators 2 are operating at high load and high efficiency. The condensate, which has been heated and deaerated by the deaerator, is pressurized by the feedwater pump 323 and heated by the high-pressure heater before entering the main feedwater header 8. Similarly, the flow rate into the economizer 102 inlet of the gas boiler 11 and the waste heat boiler 12 is controlled by the flow distributor 93, thus forming a dynamic balance in the steam-water system.

[0052] When the operation of the gas boiler 11 or waste heat boiler 12 is not matched with that of the steam turbine generator 2, that is, when the main steam generated by the boiler is greater than the main steam required by the steam turbine generator 2, the excess main steam generated by the boiler can bypass the high-pressure cylinder 21 of the steam turbine generator 2 and be directly depressurized and depressurized into the low-temperature reheat steam second branch pipe 52 of each boiler through the high-pressure bypass branch 43. Alternatively, the excess main steam can be incorporated into the main pipe, and the intake air volume of the high-pressure cylinder 21 can be adjusted in real time according to the turbine load. The high-pressure bypass branch 43 is equipped with a bypass valve 91, which (also called a bypass valve group) contains a steam valve, a water spray regulating valve, and a desuperheating water isolation valve connected in sequence. The bypass water spray adopts post-valve water spraying, which achieves the best cooling effect through steam atomization, ensuring that no local scouring and pipeline impact occur.

[0053] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical solutions, and embodiments of the present invention can be freely combined and used together.

Claims

1. A waste heat and energy power generation system for steel enterprises, characterized in that, The waste heat and waste energy power generation system of the steel enterprise includes a boiler (1), a steam turbine generator (2), a condensing device (3), a main steam header (4), a low-temperature reheat steam header (5), a high-temperature reheat steam header (6), and a main feedwater header (8). The boiler (1) includes a gas boiler (11) and a waste heat boiler (12). The steam turbine generator (2) contains a high-pressure cylinder (21) and a low-pressure cylinder (22). The main steam in the main steam header (4) can enter the high-pressure cylinder (21) of the turbine generator (2). The low-temperature reheat steam discharged from the high-pressure cylinder (21) can enter the low-temperature reheat steam header (5). The low-temperature reheat steam in the low-temperature reheat steam header (5) can enter the boiler (1) and be heated into high-temperature reheat steam and enter the high-temperature reheat steam header (6). The high-temperature reheat steam in the high-temperature reheat steam header (6) can enter the low-pressure cylinder (22) of the turbine generator (2). The working steam discharged from the low-pressure cylinder (22) can enter the condenser (3) to form condensate and enter the main feed water header (8). The condensate in the main feed water header (8) can enter the boiler (1) and be heated into the main steam and enter the main steam header (4). The boiler (1) contains a reheater (101), the low-temperature reheat steam header (5) is connected to the inlet of the reheater (101) through the low-temperature reheat steam second branch pipe (52), and the high-temperature reheat steam header (6) is connected to the outlet of the reheater (101) through the high-temperature reheat steam first branch pipe (61). The waste heat and energy power generation system of the steel enterprise also includes a low-pressure bypass steam main pipe (7) and a low-pressure bypass branch (71). A bypass valve (91) is provided on the low-pressure bypass branch (71), and an electric regulating valve (92) is provided on the first branch pipe (61) of high-temperature reheat steam. The inlet end of the low-pressure bypass branch (71) is connected to the first branch pipe (61) of high-temperature reheat steam. The inlet end of the low-pressure bypass branch (71) is located between the electric regulating valve (92) and the reheater (101). The outlet end of the low-pressure bypass branch (71) is connected to the low-pressure bypass steam main pipe (7). The boiler (1) contains an economizer (102), a water-cooled wall (103) and a superheater (104) connected in sequence. The main feedwater header (8) is connected to the economizer (102) through the main feedwater branch pipe (81). A flow distributor (93) is provided on the main feedwater branch pipe (81). The main steam header (4) is connected to the superheater (104) through the main steam second branch pipe (42). An electric regulating valve (92) is provided on the main steam second branch pipe (42). The waste heat and waste energy power generation system of the steel enterprise also includes a high-pressure bypass branch (43), which is equipped with a bypass valve (91). The inlet end of the high-pressure bypass branch (43) is connected to the second branch pipe of the main steam (42). The inlet end of the high-pressure bypass branch (43) is located between the main steam header (4) and the electric regulating valve (92). The outlet end of the high-pressure bypass branch (43) is connected to the second branch pipe of the low-temperature reheat steam (52). The second branch pipe of the low-temperature reheat steam (52) is equipped with a flow distributor (93). The outlet end of the high-pressure bypass branch (43) is located between the low-temperature reheat steam header (5) and the flow distributor (93).

2. The waste heat and energy power generation system for steel enterprises according to claim 1, characterized in that, The gas boiler (11) is an ultra-high temperature subcritical gas boiler, the waste heat boiler (12) is an ultra-high temperature subcritical waste heat boiler, the waste heat boiler (12) includes a coke oven waste heat boiler (121) and a dry quenching coke waste heat boiler (122), and the steam turbine generator (2) is an ultra-high temperature subcritical steam turbine generator.

3. The waste heat and energy power generation system for steel enterprises according to claim 1, characterized in that, The waste heat and energy power generation system of the steel enterprise includes one gas boiler (11), four coke oven waste heat boilers (121), one dry quenching coke waste heat boiler (122), two steam turbine generators (2) and two condensing units (3).

4. The waste heat and energy power generation system for steel enterprises according to claim 1, characterized in that, The main steam header (4) is connected to the inlet of the high-pressure cylinder (21) through the first branch pipe (41) of the main steam header, and the low-temperature reheat steam header (5) is connected to the outlet of the high-pressure cylinder (21) through the first branch pipe (51) of the low-temperature reheat steam header.

5. The waste heat and energy power generation system for steel enterprises according to claim 1, characterized in that, The high-temperature reheat steam header (6) is also connected to the inlet of the low-pressure cylinder (22) through the high-temperature reheat steam second branch pipe (62). The inlet of the condensing device (3) is connected to the outlet of the low-pressure cylinder (22) through the steam discharge branch pipe (31). The outlet of the condensing device (3) is connected to the main water supply header (8) through the condensate pipeline (32).

6. The waste heat and energy power generation system for steel enterprises according to claim 5, characterized in that, The condensing device (3) is a condenser. The condensing device (3) contains a three-stage water spray desuperheater (33). The low-pressure bypass steam header (7) is connected to the three-stage water spray desuperheater (33) through the low-pressure bypass steam branch pipe (72). The condensate pipeline (32) is equipped with a condensate pump (321), a deaerator and a deaerator water tank (322) and a feed water pump (323) in sequence.

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