A one-furnace two-unit thermal power system with separate heat exchange of reheat steam

Abstract

The present invention discloses a one-furnace two-machine thermal power system with separate heat exchange of reheat steam, and relates to the technical field of thermal power generation. The thermal power system comprises a coal-fired boiler, a first steam turbine generator set, a second steam turbine generator set, a feed water heat recovery system, a first steam inlet regulating valve, a second steam inlet regulating valve, a third steam inlet regulating valve and a fourth steam inlet regulating valve. The steam inlets of the two steam turbine generator sets are both provided with steam inlet regulating valves, which are relatively independently connected to the coal-fired boiler. After the two steam turbine generator sets obtain the main steam from the coal-fired boiler separately, the internal energy of the main steam is converted into mechanical energy to generate cold reheat steam, which is returned to the coal-fired boiler for heating and then transmitted to the two turbine generator sets again. The condensate generated by the two steam turbine generator sets is also returned to the coal-fired boiler for recycling after the temperature and pressure are increased by the feed water heat recovery system. The present invention improves the flexibility and stability of the unit operation.

Description

Technical Field

[0001] The invention relates to the technical field of thermal power generation, and in particular to a one-furnace two-machine thermal power system with separate heat exchange of reheated steam. Background Art

[0002] In the past few decades, the global consumption of fossil fuels and other non-renewable energy has been huge, and the environmental pollution and carbon dioxide emissions generated by the use of fossil energy and some non-renewable energy have become increasingly serious. Under the current situation, the demand for clean, efficient and flexible thermal power generation technology is becoming increasingly strong.

[0003] At present, thermal power generation systems are mainly composed of one-furnace-one-machine unit generating sets, which have the defect of poor flexibility in responding to load changes. Summary of the invention

[0004] The object of the present invention is to provide a one-furnace two-unit thermal power system with separate heat exchange of reheat steam, which can improve the flexibility and stability of unit operation.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A one-boiler two-unit thermal power system with separate reheat steam heat exchange, the thermal power system comprising: a coal-fired boiler, a first steam turbine generator set, a second steam turbine generator set, a feed water heat recovery system, a first steam inlet regulating valve, a second steam inlet regulating valve, a third steam inlet regulating valve and a fourth steam inlet regulating valve.

[0007] A main steam outlet of the coal-fired boiler is connected to a main steam inlet of the first steam turbine generator set and a main steam inlet of the second steam turbine generator set respectively; a first steam inlet regulating valve is provided on a connecting pipe between the main steam outlet of the coal-fired boiler and the main steam inlet of the first steam turbine generator set, and a second steam inlet regulating valve is provided on a connecting pipe between the main steam outlet of the coal-fired boiler and the main steam inlet of the second steam turbine generator set; the coal-fired boiler is used to heat feed water by burning coal to generate main steam, and transmit the main steam to the first steam turbine generator set and the second steam turbine generator set respectively through the first steam inlet regulating valve and the second steam inlet regulating valve; the first steam turbine generator set is used to convert the internal energy of the received main steam into mechanical energy to generate first cold reheat steam; the second steam turbine generator set is used to convert the internal energy of the received main steam into mechanical energy to generate second cold reheat steam.

[0008] The cold reheat steam outlet of the first steam turbine generator set is connected to the first cold reheat steam inlet of the coal-fired boiler, and the cold reheat steam outlet of the second steam turbine generator set is connected to the second cold reheat steam inlet of the coal-fired boiler; the first hot reheat steam outlet of the coal-fired boiler is connected to the hot reheat steam inlet of the first steam turbine generator set, and the second hot reheat steam outlet of the coal-fired boiler is connected to the hot reheat steam inlet of the second steam turbine generator set; a third steam inlet regulating valve is arranged on the connecting pipeline between the first hot reheat steam outlet of the coal-fired boiler and the hot reheat steam inlet of the first steam turbine generator set, and the second hot reheat steam outlet of the coal-fired boiler is connected to the hot reheat steam inlet of the second steam turbine generator set. A fourth steam inlet regulating valve is provided on the connecting pipeline between the hot reheat steam outlet and the hot reheat steam inlet of the second steam turbine generator set; the coal-fired boiler is also used to heat the first cold reheat steam and the second cold reheat steam respectively, and transmit the first hot reheat steam to the first steam turbine generator set after generating the first hot reheat steam, and transmit the second hot reheat steam to the second steam turbine generator set after generating the second hot reheat steam; the first steam turbine generator set is used to convert the internal energy of the first hot reheat steam into electrical energy to produce first condensate; the second steam turbine generator set is used to convert the internal energy of the second hot reheat steam into electrical energy to produce second condensate.

[0009] The condensate outlet of the first steam turbine generator set and the condensate outlet of the second steam turbine generator set are both connected to the condensate inlet of the feed water heat recovery system, and the feed water outlet of the feed water heat recovery system is connected to the feed water inlet of the coal-fired boiler; the feed water heat recovery system is used to increase the temperature and pressure of the first condensate and the second condensate, convert the first condensate and the second condensate into feed water for the coal-fired boiler, and then transmit it to the coal-fired boiler.

[0010] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0011] In an embodiment of the present invention, a one-boiler, two-unit thermal power system with separate reheat steam heat exchange is provided with steam inlet regulating valves at the steam inlets of the two steam turbine generator sets, so that the two steam turbine generator sets of the one-boiler, two-unit thermal power system are relatively independent. When one of the steam turbine generator sets is shut down due to failure, maintenance, etc., it does not affect the normal operation of the other steam turbine generator set, thereby improving the flexibility and stability of the unit operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1This is a schematic structural diagram of a one-furnace, two-unit thermal power system with separate reheat steam heat exchange provided in Example 1 of the present invention.

[0014] Explanation of symbols:

[0015] Coal-fired boiler-1, first steam turbine generator unit-2, second steam turbine generator unit-3, feed water heat recovery system-4, water-cooled wall-11, high temperature superheater-12, first high temperature reheater-13, second high temperature reheater-14, low temperature superheater-15, first low temperature reheater-16, second low temperature reheater-17, economizer-18, air preheater-19, first unit high pressure cylinder-21, first unit medium pressure cylinder-22, first unit low pressure cylinder-23, first unit condenser-24, first unit generator-25, second unit high pressure cylinder-31, second unit medium pressure cylinder-32, second unit low pressure cylinder-33, Condenser of unit 2 - 34, generator of unit 2 - 35, high pressure heater of unit 1 - 41, feed water pump of unit 1 - 42, deaerator of unit 1 - 43, low pressure heater of unit 1 - 44, high pressure heater of unit 2 - 45, feed water pump of unit 2 - 46, deaerator of unit 2 - 47, low pressure heater of unit 2 - 48, first steam inlet regulating valve - 50, second steam inlet regulating valve - 51, third steam inlet regulating valve - 52, fourth steam inlet regulating valve - 53, first bypass regulating valve - 54, second bypass regulating valve - 55, main steam main pipe - 56, diverter valve - 57, feed water main pipe - 58, combining valve - 59. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Example 1

[0019] like Figure 1 As shown, a one-boiler, two-unit thermal power system with separate reheat steam heat exchange in this embodiment includes: a coal-fired boiler 1, a first steam turbine generator set 2, a second steam turbine generator set 3, a feed water heat recovery system 4, a first steam inlet regulating valve 50, a second steam inlet regulating valve 51, a third steam inlet regulating valve 52 and a fourth steam inlet regulating valve 53.

[0020] The main steam outlet of the coal-fired boiler 1 is connected to the main steam inlet of the first steam turbine generator set 2 and the main steam inlet of the second steam turbine generator set 3 respectively. A first steam inlet regulating valve 50 is provided on the connecting pipe between the main steam outlet of the coal-fired boiler 1 and the main steam inlet of the first steam turbine generator set 2, and a second steam inlet regulating valve 51 is provided on the connecting pipe between the main steam outlet of the coal-fired boiler 1 and the main steam inlet of the second steam turbine generator set 3.

[0021] The coal-fired boiler 1 is used to heat feed water by burning coal to generate main steam, and transmit the main steam to the first steam turbine generator set 2 and the second steam turbine generator set 3 through the first steam inlet regulating valve 50 and the second steam inlet regulating valve 51 respectively. The first steam turbine generator set 2 is used to convert the internal energy of the received main steam into mechanical energy to generate the first cold reheat steam. The second steam turbine generator set 3 is used to convert the internal energy of the received main steam into mechanical energy to generate the second cold reheat steam.

[0022] The cold reheat steam outlet of the first steam turbine generator set 2 is connected to the first cold reheat steam inlet of the coal-fired boiler 1, and the cold reheat steam outlet of the second steam turbine generator set 3 is connected to the second cold reheat steam inlet of the coal-fired boiler 1. The first hot reheat steam outlet of the coal-fired boiler 1 is connected to the hot reheat steam inlet of the first steam turbine generator set 2, and the second hot reheat steam outlet of the coal-fired boiler 1 is connected to the hot reheat steam inlet of the second steam turbine generator set 3. A third steam inlet regulating valve 52 is provided on the connecting pipe between the first hot reheat steam outlet of the coal-fired boiler 1 and the hot reheat steam inlet of the first steam turbine generator set 2, and a fourth steam inlet regulating valve 53 is provided on the connecting pipe between the second hot reheat steam outlet of the coal-fired boiler 1 and the hot reheat steam inlet of the second steam turbine generator set 3.

[0023] The coal-fired boiler 1 is also used to heat the first cold reheat steam and the second cold reheat steam respectively, generate the first hot reheat steam and then transmit it to the first steam turbine generator set 2, and generate the second hot reheat steam and then transmit it to the second steam turbine generator set 3. The first steam turbine generator set 2 is used to convert the internal energy of the first hot reheat steam into electrical energy to generate the first condensate. The second steam turbine generator set 3 is used to convert the internal energy of the second hot reheat steam into electrical energy to generate the second condensate.

[0024] The condensate outlet of the first steam turbine generator set 2 and the condensate outlet of the second steam turbine generator set 3 are both connected to the condensate inlet of the feed water heat recovery system 4, and the feed water outlet of the feed water heat recovery system 4 is connected to the feed water inlet of the coal-fired boiler 1. The feed water heat recovery system 4 is used to increase the temperature and pressure of the first condensate and the second condensate, and convert the first condensate and the second condensate into feed water for the coal-fired boiler 1 and then transmit them to the coal-fired boiler 1.

[0025] The coal-fired boiler 1 generates heat energy by burning coal to heat feed water and steam, and is the energy input device of the whole system. The steam turbine generator set is connected to the coal-fired boiler 1, converts the internal energy of the steam into mechanical energy and then into electrical energy, and recovers the steam after heat release as condensate. The function of the feed water heat recovery system 4 is to increase the temperature and pressure of the condensate, so that the condensate of the steam turbine generator set is converted into feed water for the coal-fired boiler 1.

[0026] Exemplarily, the thermal power system of the present invention is a large-scale thermal power system.

[0027] Still see Figure 1 The thermal power system also includes: a cold reheat steam bypass, a hot reheat steam bypass, a first bypass regulating valve 54 and a second bypass regulating valve 55. One end of the cold reheat steam bypass is connected to a connecting pipe between the cold reheat steam outlet of the first steam turbine generator set 2 and the first cold reheat steam inlet of the coal-fired boiler 1, and the other end of the cold reheat steam bypass is connected to a connecting pipe between the cold reheat steam outlet of the second steam turbine generator set 3 and the second cold reheat steam inlet of the coal-fired boiler 1. The first bypass regulating valve 54 is arranged on the cold reheat steam bypass. One end of the hot reheat steam bypass is connected to a connecting pipe between the first hot reheat steam outlet of the coal-fired boiler 1 and the hot reheat steam inlet of the first steam turbine generator set 2, and the other end of the hot reheat steam bypass is connected to a connecting pipe between the second hot reheat steam outlet of the coal-fired boiler 1 and the hot reheat steam inlet of the second steam turbine generator set 3. The second bypass regulating valve 55 is arranged on the hot reheat steam bypass.

[0028] There are two reheat steam pipelines: two cold reheat steam pipelines are connected through a cold reheat steam bypass, and a first bypass regulating valve 54 is provided on the cold reheat steam bypass. Two hot reheat steam pipelines are connected through a hot reheat steam bypass, and a second bypass regulating valve 55 is provided on the hot reheat steam bypass. The present invention can control the steam flow in the boiler reheater by opening and closing the bypass and the corresponding regulating valve, and adjust the operating state of the boiler.

[0029] Exemplarily, the thermal power system further includes: a main steam main pipe 56, a diverter valve 57, a feed water main pipe 58 and a converging valve 59. One end of the main steam main pipe 56 is connected to the main steam outlet of the coal-fired boiler 1, and the other end of the main steam main pipe 56 is connected to the inlet of the diverter valve 57. The first outlet of the diverter valve 57 is connected to the main steam inlet of the first steam turbine generator set 2, and the second outlet of the diverter valve 57 is connected to the main steam inlet of the second steam turbine generator set 3. The water inlet of the converging valve 59 is connected to the feed water outlet of the feed water regeneration system 4, the water outlet of the converging valve 59 is connected to one end of the feed water main pipe 58, and the other end of the feed water main pipe 58 is connected to the feed water inlet of the coal-fired boiler 1. The feed water main pipe 58 is used to merge the first condensate and the second condensate through the converging valve 59 to obtain the feed water of the coal-fired boiler 1, and transmit the merged feed water to the coal-fired boiler 1.

[0030] The steam inlet regulating valve on the main steam header 56 connecting pipeline and the bypass regulating valve of the reheat steam bypass are relatively independent and can respectively control the steam flow of the high pressure cylinder and the medium and low pressure cylinder of the two steam turbine generator sets.

[0031] The heat load distribution between the two steam turbine generator sets can be flexibly controlled by the following regulating valves: the regulating valves (the first steam inlet regulating valve 50, the second steam inlet regulating valve 51, the third steam inlet regulating valve 52 and the fourth steam inlet regulating valve 53) arranged at one end of the main steam main pipe 56 (steam pipeline main pipe) connected to the steam turbine generator set, the first bypass regulating valve 54 provided on the cold reheat steam bypass, and the second bypass regulating valve 55 provided on the hot reheat steam bypass. The method of controlling the load distribution by the regulating valve is to adjust the steam flow in the steam pipeline and control the heat input to the steam turbine set by distributing the steam in a certain proportion.

[0032] The specific components, structures and functions of the coal-fired boiler 1, the first steam turbine generator set 2, the second steam turbine generator set 3 and the feed water heat recovery system 4 are described in detail below.

[0033] (I) Coal-fired boiler 1

[0034] The coal-fired boiler 1 includes an economizer 18 , a water-cooled wall 11 , a low-temperature superheater 15 , a high-temperature superheater 12 , a first low-temperature reheater 16 , a second low-temperature reheater 17 , a first high-temperature reheater 13 and a second high-temperature reheater 14 .

[0035] The feed water inlet of the economizer 18 is connected to the feed water outlet of the feed water regeneration system 4, and the feed water outlet of the economizer 18 is connected to the feed water inlet of the water wall 11. The steam outlet of the water wall 11 is connected to the steam inlet of the low-temperature superheater 15, and the steam outlet of the low-temperature superheater 15 is connected to the steam inlet of the high-temperature superheater 12, and the steam outlet of the high-temperature superheater 12 is respectively connected to the main steam inlet of the first steam turbine generator set 2 and the main steam inlet of the second steam turbine generator set 3. After the feed water flows through the economizer 18, it flows into the water wall 11, and is vaporized into steam in the water wall 11. The steam flows through the low-temperature superheater 15 and the high-temperature superheater 12 in sequence, and finally becomes the main steam.

[0036] The cold reheat steam inlet of the first low-temperature reheater 16 is connected to the cold reheat steam outlet of the first steam turbine generator set 2, the cold reheat steam outlet of the first low-temperature reheater 16 is connected to the cold reheat steam inlet of the first high-temperature reheater 13, and the hot reheat steam outlet of the first high-temperature reheater 13 is connected to the hot reheat steam inlet of the first steam turbine generator set 2. The first cold reheat steam flows through the first low-temperature reheater 16 and the first high-temperature reheater 13 in sequence, is heated to hot reheat steam, and is then transmitted to the first steam turbine generator set 2.

[0037] The cold reheat steam inlet of the second low-temperature reheater 17 is connected to the cold reheat steam outlet of the second steam turbine generator set 3, the cold reheat steam outlet of the second low-temperature reheater 17 is connected to the cold reheat steam inlet of the second high-temperature reheater 14, and the hot reheat steam outlet of the second high-temperature reheater 14 is connected to the hot reheat steam inlet of the second steam turbine generator set 3. The second cold reheat steam flows through the second low-temperature reheater 17 and the second high-temperature reheater 14 in sequence, is heated to hot reheat steam, and is then transmitted to the second steam turbine generator set 3.

[0038] The two steam turbine generator sets have their own reheat steam pipes, so the coal-fired boiler 1 has two groups of reheaters. The first low-temperature reheater 16 is connected to the first high-temperature reheater 13 by a pipe inside the boiler, and is the reheater of the first steam turbine generator set 2. The second low-temperature reheater 17 is connected to the second high-temperature reheater 14 by a pipe inside the boiler, and is the reheater of the second steam turbine generator set 3.

[0039] The economizer 18 is a heating surface that heats the boiler feed water to saturated water at drum pressure.

[0040] The coal-fired boiler 1 further includes: a boiler furnace and an air preheater 19. The water-cooled walls 11 are distributed around the boiler furnace. The flue gas inlet of the air preheater 19 is connected to the flue gas outlet of the economizer 18, and the air outlet of the air preheater 19 is connected to the air inlet of the boiler furnace. The air preheater 19 is used to heat the air using the heat of the flue gas flowing out of the economizer 18, and transmit the heated air to the boiler furnace. The flue gas flowing out of the air preheater 19 is discharged after being purified.

[0041] Arranged in the order of flue gas flow, the following heat exchangers are arranged in the coal-fired boiler 1: water-cooled wall 11, high-temperature superheater 12, first high-temperature reheater 13, second high-temperature reheater 14, low-temperature superheater 15, first low-temperature reheater 16, second low-temperature reheater 17, economizer 18 and air preheater 19. Inside the boiler, the steam-water pipes of the above heat exchangers are partially interconnected, specifically: the feed water first enters the economizer 18, flows through the economizer 18 and then flows into the water-cooled wall 11, vaporizes into steam in the water-cooled wall 11, and the steam flows through the low-temperature superheater 15 and the high-temperature superheater 12 in turn, and finally becomes the main steam. The cold reheat steam of the first steam turbine unit flows through the first low-temperature reheater 16 and the first high-temperature reheater 13 in turn, and is heated to hot reheat steam. The cold reheat steam of the second steam turbine unit flows through the second low-temperature reheater 17 and the second high-temperature reheater 14 in turn, and is heated to hot reheat steam.

[0042] (II) Water supply heat recovery system 4

[0043] The feed water heat recovery system 4 includes: a first unit heat recovery system and a second unit heat recovery system. The condensate inlet of the first unit heat recovery system is connected to the condensate outlet of the first steam turbine generator set 2, the condensate inlet of the second unit heat recovery system is connected to the condensate outlet of the second steam turbine generator set 3, and the feed water outlet of the first unit heat recovery system and the feed water outlet of the second unit heat recovery system are both connected to the feed water inlet of the coal-fired boiler 1.

[0044] Specifically, the first unit heat recovery system includes: a first unit low-pressure heater 44, a first unit deaerator 43, a first unit feed water pump 42 and a first unit high-pressure heater 41. According to the flow direction of the first condensate, the first unit low-pressure heater 44, the first unit deaerator 43, the first unit feed water pump 42 and the first unit high-pressure heater 41 are connected in sequence. The first condensate first flows through the first unit low-pressure heater 44 and the first unit deaerator 43, is heated to the saturation temperature, and then enters the first unit high-pressure heater 41 after being pressurized by the first unit feed water pump 42 to continue to be heated, and is converted into feed water for the coal-fired boiler 1.

[0045] The second unit heat recovery system includes: a second unit low-pressure heater 48, a second unit deaerator 47, a second unit feed water pump 46 and a second unit high-pressure heater 45. According to the flow direction of the second condensate, the second unit low-pressure heater 48, the second unit deaerator 47, the second unit feed water pump 46 and the second unit high-pressure heater 45 are connected in sequence. The second condensate first flows through the second unit low-pressure heater 48 and the second unit deaerator 47, is heated to the saturation temperature, and then enters the second unit high-pressure heater 45 after being pressurized by the second unit feed water pump 46 to continue to be heated, and is converted into feed water for the coal-fired boiler 1.

[0046] The working medium at the outlets of the first unit high pressure heater 41 and the second unit high pressure heater 45 is boiler feed water.

[0047] (III) First steam turbine generator set 2

[0048] The first steam turbine generator unit 2 comprises: a first unit high pressure cylinder 21 , a first unit intermediate pressure cylinder 22 , a first unit low pressure cylinder 23 , a first unit condenser 24 and a first unit generator 25 .

[0049] The high pressure cylinder 21 of the first unit, the medium pressure cylinder 22 of the first unit, the low pressure cylinder 23 of the first unit and the generator 25 of the first unit are connected in sequence through a shaft. The main steam inlet of the high pressure cylinder 21 of the first unit is connected to the main steam outlet of the coal-fired boiler 1, and the cold reheat steam outlet of the high pressure cylinder 21 of the first unit is connected to the first cold reheat steam inlet of the coal-fired boiler 1. The hot reheat steam inlet of the medium pressure cylinder 22 of the first unit is connected to the first hot reheat steam outlet of the coal-fired boiler 1, the steam outlet of the medium pressure cylinder 22 of the first unit is connected to the steam inlet of the low pressure cylinder 23 of the first unit, and the steam outlet of the low pressure cylinder 23 of the first unit is connected to the steam inlet of the condenser 24 of the first unit. The condensate outlet of the condenser 24 of the first unit is connected to the condensate inlet of the heat recovery system of the first unit.

[0050] The function of the shaft is to connect the high-pressure cylinder, medium-pressure cylinder, low-pressure cylinder and generator of the steam turbine, and transfer the mechanical energy output by the steam turbine to the generator.

[0051] (IV) Second steam turbine generator set 3

[0052] The second steam turbine generator set 3 has the same structure as the first steam turbine generator set 2 .

[0053] The second steam turbine generator set 3 comprises: a second unit high pressure cylinder 31 , a second unit intermediate pressure cylinder 32 , a second unit low pressure cylinder 33 , a second unit condenser 34 and a second unit generator 35 .

[0054] The high pressure cylinder 31 of the second unit, the medium pressure cylinder 32 of the second unit, the low pressure cylinder 33 of the second unit and the generator 35 of the second unit are connected in sequence through a shaft. The main steam inlet of the high pressure cylinder 31 of the second unit is connected to the main steam outlet of the coal-fired boiler 1, and the cold reheat steam outlet of the high pressure cylinder 31 of the second unit is connected to the second cold reheat steam inlet of the coal-fired boiler 1. The hot reheat steam inlet of the medium pressure cylinder 32 of the second unit is connected to the second hot reheat steam outlet of the coal-fired boiler 1, the steam outlet of the medium pressure cylinder 32 of the second unit is connected to the steam inlet of the low pressure cylinder 33 of the second unit, and the steam outlet of the low pressure cylinder 33 of the second unit is connected to the steam inlet of the condenser 34 of the second unit. The condensate outlet of the condenser 34 of the second unit is connected to the condensate inlet of the heat recovery system of the second unit.

[0055] The function of the two steam turbine generator sets is to convert the energy carried by the working fluid into electrical energy.

[0056] It is necessary for the coal-fired boiler 1 and two sets of steam turbines in the one-boiler-two-machine arrangement described in the present invention to have matching operating parameters, including that the thermal load of the boiler should be the sum of the loads of the two steam turbine generator sets in real time, and the parameters of the steam required by the two steam turbine generator sets should be relatively close.

[0057] On the basis of the system of the present invention, a control system can also be configured for load distribution between the two steam turbine units, which is used to monitor the load requirements of the power system and adjust the power generation of the two steam turbine generator sets accordingly according to actual requirements. The two steam turbines can use different operating loads.

[0058] A one-furnace two-unit thermal power system with separate reheat steam heat exchange of the present invention comprises: a coal-fired boiler 1, a main steam main pipe 56, a cold reheat steam bypass, a hot reheat steam bypass, a feedwater main pipe 58, a No. 1 steam turbine generator set, and a No. 2 steam turbine generator set. The inlet of the main steam main pipe 56 is connected to the outlet of the high-temperature superheater 12 of the coal-fired boiler 1, the cold reheat steam pipeline is connected through the cold reheat steam bypass, and is connected to the low-temperature reheater and the high-temperature reheater in sequence, the high-temperature reheater outlet is connected to the hot reheat steam pipeline, and the hot reheat steam pipeline is connected through the bypass. The present invention forms an integral system with a boiler and two sets of steam turbine generator sets by using the main steam main pipe 56 and the reheat steam pipeline connected by the bypass. A reasonable load distribution strategy is adopted during operation to enable the system to obtain higher operating flexibility and stability, and at the same time effectively improve the operating efficiency of the unit at low load.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] 1. The use of a one-furnace-two-unit thermal power system solves the defects of the one-furnace-one-unit unit generator set, which has poor flexibility in responding to load changes and low power generation efficiency under low-load operation.

[0061] 2. The two steam turbine units in the one-furnace-two-unit power generation system are relatively independent. The shutdown of one unit due to failure, maintenance, etc. will not affect the normal operation of the other unit.

[0062] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the system and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A one-furnace two-unit thermal power system with separate reheat steam heat exchange, characterized in that: The thermal power system comprises: a coal-fired boiler, a first steam turbine generator set, a second steam turbine generator set, a feed water heat recovery system, a first steam inlet regulating valve, a second steam inlet regulating valve, a third steam inlet regulating valve and a fourth steam inlet regulating valve; The main steam outlet of the coal-fired boiler is connected to the main steam inlet of the first steam turbine generator set and the main steam inlet of the second steam turbine generator set respectively, a first steam inlet regulating valve is provided on the connecting pipe between the main steam outlet of the coal-fired boiler and the main steam inlet of the first steam turbine generator set, and a second steam inlet regulating valve is provided on the connecting pipe between the main steam outlet of the coal-fired boiler and the main steam inlet of the second steam turbine generator set; The coal-fired boiler is used to heat feed water by burning coal to generate main steam, and transmit the main steam to the first steam turbine generator set and the second steam turbine generator set respectively through the first steam inlet regulating valve and the second steam inlet regulating valve; the first steam turbine generator set is used to convert the internal energy of the received main steam into mechanical energy to generate first cold reheat steam; the second steam turbine generator set is used to convert the internal energy of the received main steam into mechanical energy to generate second cold reheat steam; The cold reheat steam outlet of the first steam turbine generator set is connected to the first cold reheat steam inlet of the coal-fired boiler, and the cold reheat steam outlet of the second steam turbine generator set is connected to the second cold reheat steam inlet of the coal-fired boiler; the first hot reheat steam outlet of the coal-fired boiler is connected to the hot reheat steam inlet of the first steam turbine generator set, and the second hot reheat steam outlet of the coal-fired boiler is connected to the hot reheat steam inlet of the second steam turbine generator set; a third steam inlet regulating valve is provided on the connecting pipeline between the first hot reheat steam outlet of the coal-fired boiler and the hot reheat steam inlet of the first steam turbine generator set, and a fourth steam inlet regulating valve is provided on the connecting pipeline between the second hot reheat steam outlet of the coal-fired boiler and the hot reheat steam inlet of the second steam turbine generator set; The coal-fired boiler is also used to heat the first cold reheat steam and the second cold reheat steam respectively, generate the first hot reheat steam and then transmit it to the first steam turbine generator set, and generate the second hot reheat steam and then transmit it to the second steam turbine generator set; the first steam turbine generator set is used to convert the internal energy of the first hot reheat steam into electrical energy to generate the first condensate; the second steam turbine generator set is used to convert the internal energy of the second hot reheat steam into electrical energy to generate the second condensate; The condensate outlet of the first steam turbine generator set and the condensate outlet of the second steam turbine generator set are both connected to the condensate inlet of the feed water heat recovery system, and the feed water outlet of the feed water heat recovery system is connected to the feed water inlet of the coal-fired boiler; The feed water heat recovery system is used to increase the temperature and pressure of the first condensed water and the second condensed water, convert the first condensed water and the second condensed water into feed water for the coal-fired boiler, and then transmit them to the coal-fired boiler; The coal-fired boiler comprises: a first low-temperature reheater, a second low-temperature reheater, a first high-temperature reheater and a second high-temperature reheater; The cold reheat steam inlet of the first low-temperature reheater is connected to the cold reheat steam outlet of the first steam turbine generator set, the cold reheat steam outlet of the first low-temperature reheater is connected to the cold reheat steam inlet of the first high-temperature reheater, and the hot reheat steam outlet of the first high-temperature reheater is connected to the hot reheat steam inlet of the first steam turbine generator set; The first cold reheat steam flows through the first low-temperature reheater and the first high-temperature reheater in sequence, is heated to become hot reheat steam, and is then transmitted to the first steam turbine generator set; The cold reheat steam inlet of the second low-temperature reheater is connected to the cold reheat steam outlet of the second steam turbine generator set, the cold reheat steam outlet of the second low-temperature reheater is connected to the cold reheat steam inlet of the second high-temperature reheater, and the hot reheat steam outlet of the second high-temperature reheater is connected to the hot reheat steam inlet of the second steam turbine generator set; The second cold reheat steam flows through the second low-temperature reheater and the second high-temperature reheater in sequence, is heated to become hot reheat steam, and is then transmitted to the second steam turbine generator set; The thermal power system further includes: a cold reheat steam bypass, a hot reheat steam bypass, a first bypass regulating valve and a second bypass regulating valve; One end of the cold reheat steam bypass is connected to a connecting pipe between the cold reheat steam outlet of the first steam turbine generator set and the first cold reheat steam inlet of the coal-fired boiler, and the other end of the cold reheat steam bypass is connected to a connecting pipe between the cold reheat steam outlet of the second steam turbine generator set and the second cold reheat steam inlet of the coal-fired boiler; the first bypass regulating valve is arranged on the cold reheat steam bypass; One end of the hot reheat steam bypass is connected to a connecting pipe between a first hot reheat steam outlet of the coal-fired boiler and a hot reheat steam inlet of the first steam turbine generator set, and the other end of the hot reheat steam bypass is connected to a connecting pipe between a second hot reheat steam outlet of the coal-fired boiler and a hot reheat steam inlet of the second steam turbine generator set; a second bypass regulating valve is arranged on the hot reheat steam bypass; The steam flow in the boiler reheater is controlled by opening and closing the bypass and bypass regulating valve to adjust the operating state of the boiler; The heat load distribution between the two steam turbine generator sets is flexibly controlled by the following regulating valves: the first steam inlet regulating valve, the second steam inlet regulating valve, the third steam inlet regulating valve and the fourth steam inlet regulating valve, the first bypass regulating valve on the cold reheat steam bypass, and the second bypass regulating valve on the hot reheat steam bypass; the method by which the regulating valve controls the load distribution is to adjust the steam flow in the steam pipeline, and to control the heat input to the steam turbine set by distributing steam in a certain proportion; the two sets of steam turbines use different operating loads.

2. The one-furnace two-unit thermal power system with separate reheat steam heat exchange according to claim 1 is characterized in that: The thermal power system further includes: a main steam main pipe, a diverter valve, a water supply main pipe and a converging valve; One end of the main steam main pipe is connected to the main steam outlet of the coal-fired boiler, and the other end of the main steam main pipe is connected to the inlet of the diverter valve; the first outlet of the diverter valve is connected to the main steam inlet of the first steam turbine generator set, and the second outlet of the diverter valve is connected to the main steam inlet of the second steam turbine generator set; The water inlet of the combining valve is connected to the water outlet of the water supply heat recovery system, the water outlet of the combining valve is connected to one end of the water supply mother pipe, and the other end of the water supply mother pipe is connected to the water supply inlet of the coal-fired boiler; the water supply mother pipe is used to obtain the feed water for the coal-fired boiler by combining the first condensate and the second condensate through the combining valve, and transmit the combined feed water to the coal-fired boiler.

3. The one-furnace two-unit thermal power system with separate reheat steam heat exchange according to claim 1 is characterized in that: The coal-fired boiler comprises: an economizer, a water-cooled wall, a low-temperature superheater and a high-temperature superheater; The feed water inlet of the economizer is connected to the feed water outlet of the feed water heat recovery system, and the feed water outlet of the economizer is connected to the feed water inlet of the water wall; the steam outlet of the water wall is connected to the steam inlet of the low-temperature superheater, and the steam outlet of the low-temperature superheater is connected to the steam inlet of the high-temperature superheater, and the steam outlet of the high-temperature superheater is respectively connected to the main steam inlet of the first steam turbine generator set and the main steam inlet of the second steam turbine generator set; The feed water flows through the economizer and then into the water-cooled wall, where it vaporizes into steam. The steam then flows through the low-temperature superheater and the high-temperature superheater in turn, and finally becomes the main steam.

4. The one-furnace two-unit thermal power system with separate reheat steam heat exchange according to claim 3 is characterized in that: The coal-fired boiler also includes: a boiler furnace and an air preheater; The water-cooled walls are distributed around the boiler furnace; The flue gas inlet of the air preheater is connected to the flue gas outlet of the economizer, and the air outlet of the air preheater is connected to the air inlet of the boiler furnace; The air preheater is used to heat the air using the heat of the flue gas flowing out of the economizer, and transmit the heated air to the boiler furnace.

5. The one-furnace two-unit thermal power system with separate reheat steam heat exchange according to claim 1 is characterized in that: The feed water heat recovery system comprises: a first unit heat recovery system and a second unit heat recovery system; The condensate inlet of the first unit's heat recovery system is connected to the condensate outlet of the first steam turbine generator unit, the condensate inlet of the second unit's heat recovery system is connected to the condensate outlet of the second steam turbine generator unit, and the feed water outlet of the first unit's heat recovery system and the feed water outlet of the second unit's heat recovery system are both connected to the feed water inlet of the coal-fired boiler.

6. The one-furnace two-unit thermal power system with separate reheat steam heat exchange according to claim 5 is characterized in that: The first unit heat recovery system includes: a first unit low-pressure heater, a first unit deaerator, a first unit feedwater pump and a first unit high-pressure heater; According to the flow direction of the first condensate, the first unit low-pressure heater, the first unit deaerator, the first unit feedwater pump and the first unit high-pressure heater are connected in sequence; The first condensate first flows through the first unit low-pressure heater and the first unit deaerator, is heated to the saturation temperature, and then enters the first unit high-pressure heater after being pressurized by the first unit feed water pump to continue being heated and converted into feed water for the coal-fired boiler.

7. The one-furnace two-unit thermal power system with separate reheat steam heat exchange according to claim 6 is characterized in that: The second unit heat recovery system includes: a second unit low-pressure heater, a second unit deaerator, a second unit feedwater pump, and a second unit high-pressure heater; According to the flow direction of the second condensate, the second unit low-pressure heater, the second unit deaerator, the second unit feedwater pump and the second unit high-pressure heater are connected in sequence; The second condensate first flows through the second unit low-pressure heater and the second unit deaerator, is heated to the saturation temperature, and then enters the second unit high-pressure heater after being pressurized by the second unit feed water pump to continue being heated and converted into feed water for the coal-fired boiler.

8. The one-furnace two-unit thermal power system with separate reheat steam heat exchange according to claim 5 is characterized in that: The first steam turbine generator set comprises: a first unit high pressure cylinder, a first unit medium pressure cylinder, a first unit low pressure cylinder, a first unit condenser and a first unit generator; The high-pressure cylinder of the first unit, the medium-pressure cylinder of the first unit, the low-pressure cylinder of the first unit and the generator of the first unit are connected in sequence through a shaft; The main steam inlet of the high-pressure cylinder of the first unit is connected to the main steam outlet of the coal-fired boiler, and the cold reheat steam outlet of the high-pressure cylinder of the first unit is connected to the first cold reheat steam inlet of the coal-fired boiler; The hot reheat steam inlet of the intermediate pressure cylinder of the first unit is connected to the first hot reheat steam outlet of the coal-fired boiler, the steam outlet of the intermediate pressure cylinder of the first unit is connected to the steam inlet of the low pressure cylinder of the first unit, the steam outlet of the low pressure cylinder of the first unit is connected to the steam inlet of the condenser of the first unit; the condensate outlet of the condenser of the first unit is connected to the condensate inlet of the heat recovery system of the first unit.

9. The one-furnace two-unit thermal power system with separate reheat steam heat exchange according to claim 5, characterized in that: The second steam turbine generator set comprises: a second unit high pressure cylinder, a second unit medium pressure cylinder, a second unit low pressure cylinder, a second unit condenser and a second unit generator; The high-pressure cylinder of the second unit, the medium-pressure cylinder of the second unit, the low-pressure cylinder of the second unit and the generator of the second unit are connected in sequence through a shaft; The main steam inlet of the high-pressure cylinder of the second unit is connected to the main steam outlet of the coal-fired boiler, and the cold reheat steam outlet of the high-pressure cylinder of the second unit is connected to the second cold reheat steam inlet of the coal-fired boiler; The hot reheat steam inlet of the intermediate pressure cylinder of the second unit is connected to the second hot reheat steam outlet of the coal-fired boiler, the steam outlet of the intermediate pressure cylinder of the second unit is connected to the steam inlet of the low pressure cylinder of the second unit, the steam outlet of the low pressure cylinder of the second unit is connected to the steam inlet of the condenser of the second unit; the condensate outlet of the condenser of the second unit is connected to the condensate inlet of the heat recovery system of the second unit.

Images