Unit starting energy-saving device and energy-saving method

Abstract

The unit starting energy-saving device comprises a first unit, a second unit, a first deaerator and a second deaerator, an interconnection water supply pipeline of the first unit is communicated with a second heat release branch water supply pipeline of the second unit, and the second heat release branch water supply pipeline is communicated with a second heat release branch water return pipeline. The second heat release branch water return pipeline communicates with the interconnection water return pipeline, the first unit communicates with the second unit through the interconnection water return pipeline, the first unit is provided with a first deaerator, and the second unit is provided with a second deaerator. Through the mechanism, the problem of energy waste caused by using high-quality steam of the adjacent machine in the starting process of the unit is solved, high-temperature flue gas directly discharged in normal production of the adjacent machine is effectively utilized to replace the high-quality steam of the adjacent machine in the starting process of the unit, and low-quality energy is utilized to replace high-quality energy; and the energy consumption in the starting process of the unit is greatly reduced due to the fact that flue gas lost energy cannot be effectively recycled.

Description

Technical Field

[0001] The present invention relates to the technical field of starting of thermal power generating units, and particularly relates to a unit starting energy-saving device and an energy-saving method. Background Art

[0002] With the increase in the new energy load absorbed by the power grid, under the new power grid structure, the peak shaving depth of thermal power generation enterprises has increased, the peak shaving frequency of thermal power plants during startup has increased, and the demand for energy saving during startup of thermal power generation enterprises has increased. When the unit starts up, the feed water temperature is increased to reduce the fuel consumption during the startup process and reduce the unit startup cost. The common method of heating the feed water is to use the high-quality steam of the adjacent unit for feed water heating.

[0003] The existing feed water heating is to lead the steam generated by the adjacent unit to the deaerator through the auxiliary steam header to heat the feed water in the deaerator. The heated feed water is pumped to the boiler to absorb heat and cool the boiler, and the generated steam is used for turbine turning. However, the high-temperature flue gas generated by the adjacent unit is directly discharged, and the energy of the flue gas cannot be effectively utilized, resulting in the loss of flue gas energy. Summary of the Invention

[0004] The present invention provides a unit starting energy-saving device and an energy-saving method, which solve the energy waste caused by using the high-quality steam of the adjacent unit during the unit startup process, effectively utilize the low-quality high-temperature flue gas directly discharged during the normal production of the adjacent unit to replace the high-quality steam of the adjacent unit used during the unit startup process, use low-quality energy to replace high-quality energy, and recover the energy loss of the flue gas that cannot be effectively utilized, greatly reducing the energy consumption during the unit startup process.

[0005] The technical solution of the present invention for solving the above technical problems is as follows:

[0006] A unit starting energy-saving device includes a first unit, a second unit, a first deaerator and a second deaerator. The interconnected water supply pipeline of the first unit is connected to the second heat release branch water supply pipeline of the second unit. The second heat release branch water supply pipeline is connected to the second heat release branch return water pipeline. The second heat release branch return water pipeline is connected to the interconnected return water pipeline. The first unit and the second unit are connected through the interconnected return water pipeline. The first unit is provided with a first deaerator, and the second unit is provided with a second deaerator.

[0007] The beneficial effects of adopting the above solution are as follows: The flue gas generated by the first unit is used to heat and produce hot water. Then, the hot water is supplied to the water supply pipeline of the second heat release branch of the second unit through the interconnected water supply pipeline. The cold water after heat release is returned to the first unit again through the interconnected return water pipeline of the second unit. The high temperature of the flue gas is used to provide heat for the heat cycle of the original system and the adjacent unit. The heat of the first unit or the second unit is transferred from the adjacent unit to the condensate system of this unit and flows into the first deaerator or the second deaerator for heat exchange. The greater the heat exchange amount in the deaerator, the less heat generated by the fuel absorbed in the boiler, and thus the more fuel is saved. By recovering the waste heat of the boiler flue gas, the heat loss of the boiler is reduced, the thermal efficiency of the boiler is improved, the energy consumption of using high-quality steam from the adjacent unit is reduced, the feed water temperature is increased, and the energy consumption during the startup process is reduced. At the same time, by using the original system, the investment is low, the recovery period is short, and the startup cost of the unit is reduced.

[0008] Furthermore, the first unit and the second unit have the same composition structure.

[0009] The first unit includes a first interconnected heat medium water system, a heat absorption module, a first heat exchange group, a first water-water heat exchanger, and a first condensate system. The outlet pipe of the interconnected heat medium water system is connected to the flue gas cooler of the heat absorption module. The outlet pipes of the heat absorption module are respectively connected to the recirculation pipeline, the first heat release branch, the second heat release branch, and the interconnected water supply pipeline. The inlet pipe of the first heat exchange group is connected to the first heat release branch. The outlet pipe of the first heat exchange group is connected to the return water pipeline of the first heat release branch and is connected to the interconnected heat medium water system through the return water pipeline of the first heat release branch. The inlet pipe of the heat release side of the first water-water heat exchanger is connected to the second heat release branch. The outlet pipe of the heat release side of the first water-water heat exchanger is connected to the first interconnected heat medium water system. The pipeline on the heat absorption side of the heat absorption module is connected to the first condensate system; the outlet pipe of the heat absorption module is connected to the first interconnected heat medium water system through the recirculation pipeline; the outlet pipe of the heat absorption module is connected to the water supply pipeline of the second heat release branch of the second unit through the interconnected water supply pipeline.

[0010] The beneficial effects of adopting the above further solution are as follows: When two identical units are operating, during the operation of the first unit, the flue gas flowing through the heat absorption module heats the feed water. At the same time, the hot water in the heat absorption module is divided into four branches for circulating flow. When the hot water in the heat absorption module enters the return water pipeline of the first heat release branch through the recirculation pipeline, and then enters the first interconnected heat medium water system through the return water pipeline of the first heat release branch; when the hot water in the heat absorption module enters the first heat release branch through the first outlet pipe, and then enters the first heat exchange group through the first heat release branch, releases heat through the first heat exchange group, and then returns to the first interconnected heat medium water system through the return water pipeline of the first heat release branch; when the hot water in the heat absorption module enters the first water-water heat exchanger through the second heat release branch, and then returns to the first interconnected heat medium water system through the outlet pipeline of the first water-water heat exchanger; at the same time, the hot water in the heat absorption module also enters the supply water pipeline of the second heat release branch of the second unit through the interconnected supply water pipeline of the first unit, and then enters the second water-water heat exchanger through the return water pipeline of the second heat release branch, and then enters the first interconnected heat medium water system;

[0011] The high temperature of the flue gas provides heat for the thermal cycle of the original system and the adjacent unit. By recovering the heat of the boiler's exhaust gas, the heat loss of the boiler is reduced, the thermal efficiency of the boiler is improved, and the energy of using high-quality steam from the adjacent unit is reduced, the feed water temperature is increased, and the energy consumption during the startup process is reduced. At the same time, by using the original system, the investment is low, the recovery period is short, and the startup cost of the unit is reduced.

[0012] Furthermore, regulating valves are provided at both the first condensate system and the second condensate system of the second unit;

[0013] The hot water of the first unit transfers heat to the first condensate system through the first water-water heat exchanger;

[0014] The hot water of the second unit transfers heat to the second condensate system through the second water-water heat exchanger.

[0015] The beneficial effects of adopting the above further solution are as follows: The hot water generated by the adjacent unit exchanges heat through the first water-water heat exchanger and enters the first condensate system, and then the heat energy enters the deaerator through the condensate system. The heated feed water is pumped to the boiler to absorb heat and cool the boiler, and the generated steam is used for turbine rotation. By providing a regulating valve at the first condensate system, the condensate temperature can be adjusted according to the required feed water temperature of the boiler, ensuring that the feed water temperature meets the requirements of the boiler, saving startup fuel to the greatest extent, and reducing the startup cost of the unit.

[0016] Furthermore, a first regulating device is provided on the interconnected return water pipeline, and the first regulating device regulates the connection or closure of the interconnected return water pipeline;

[0017] A second regulating device is provided on the interconnected supply water pipeline, and the second regulating device regulates the connection or closure of the interconnected supply water pipeline.

[0018] The beneficial effect of adopting the above further solution is that a first regulating device is provided on the interconnected return water pipeline of the first unit, and a second regulating device is provided on the interconnected return water pipeline of the second unit. The first unit is regulated by the first regulating device, and the connection or closing between the interconnected return water pipelines of the second unit is regulated by the second regulating device.

[0019] On the other hand, a unit startup energy-saving method, based on the above unit startup energy-saving device, the energy-saving method is as follows:

[0020] When the first unit is operating and the second unit is stopped, the first regulating device and the second regulating device are opened, and the first interconnected heat medium water system is connected to the second interconnected heat medium water system of the second unit;

[0021] And / or, when the second unit is operating and the first unit is stopped, the first regulating device and the second regulating device are opened, and the second unit is connected to the first interconnected heat medium water system through the second interconnected heat medium water system.

[0022] The beneficial effect of adopting the above further solution is that the first unit and the second unit operate independently. When starting another unit during independent operation, the heat is transferred from the local unit to the condensate system of the adjacent unit and then flows into the deaerator for use.

[0023] Further, when the first unit and the second unit operate simultaneously, the first regulating device and the second regulating device are closed, and the first interconnected heat medium water system is not connected to the second interconnected heat medium water system; the second interconnected heat medium water system 23 of the second unit is not connected to the first interconnected heat medium water system 11.

[0024] The beneficial effect of adopting the above further solution is that when the flue gas waste heat of the adjacent unit is insufficient, the original auxiliary heating system is still used to maintain the water temperature requirement during startup and save fuel.

[0025] Further, a unit startup energy-saving method, the energy-saving steps are as follows:

[0026] When the first unit is operating and the second unit is stopped:

[0027] S1: The cold water in the heat absorption module absorbs the heat in the boiler flue gas to form hot water.

[0028] S2: The hot water in the heat absorption module enters the return water pipeline of the first heat release branch through the recirculation pipeline and then returns to the first interconnected heat medium water system through the return water pipeline of the first heat release branch;

[0029] S3: The hot water in the heat absorption module enters the first heat release branch through the first water outlet pipe, then enters the first heat exchange group through the first heat release branch, exchanges heat through the first heat exchange group, and then returns to the first interconnected heat medium water system through the return water pipeline of the first heat release branch;

[0030] S4: The hot water in the heat absorption module enters the first water-water heat exchanger through the second heat release branch, and then returns to the first interconnected heat medium water system through the outlet pipeline of the first water-water heat exchanger;

[0031] S5: The hot water in the heat absorption module enters the supply water pipeline of the second heat release branch of the second unit through the interconnected supply water pipeline of the first unit;

[0032] The hot water in the supply water pipeline of the second heat release branch enters the second water-water heat exchanger, and returns to the first interconnected heat medium water system through the return water pipeline of the second heat release branch and the interconnected return water pipeline;

[0033] S6: The heat absorption side of the second water-water heat exchanger is connected to the condensate water from the direction of the second condensate water system. After absorbing heat through the second water-water heat exchanger, it enters the second condensate water system.

[0034] Steps S1, S2, S3, S4, S5, and S6 are respectively and independently reciprocally cycled in this way.

[0035] The beneficial effect of adopting the above further solution is that two identical units operate. When the first unit operates, it absorbs the heat in the boiler flue gas by the cold water in the heat absorption module to form hot water. At the same time, the hot water in the heat absorption module is divided into four branches for circulating flow. When the hot water in the heat absorption module enters the return water pipeline of the first heat release branch through the recirculation pipeline, and then returns to the first interconnected heat medium water system through the return water pipeline of the first heat release branch; when the hot water in the heat absorption module enters the first heat release branch through the first water outlet pipe, then enters the first heat exchange group through the first heat release branch, is heated through the first heat exchange group, and then enters the return water pipeline of the first heat release branch through the first heat exchange group and returns to the first interconnected heat medium water system; when the hot water in the heat absorption module enters the first water-water heat exchanger through the second heat release branch, and then returns to the first interconnected heat medium water system through the outlet pipeline of the first water-water heat exchanger;

[0036] At the same time, the hot water in the heat absorption module will also enter the supply water pipeline of the second heat release branch of the second unit through the interconnected supply water pipeline of the first unit. Then, the hot water in the supply water pipeline of the second heat release branch enters the second water-water heat exchanger through the return water pipeline of the second heat release branch, and then returns to the first interconnected heat medium water system through the interconnected return water pipeline; the heat absorption side of the second water-water heat exchanger is connected to the condensate water from the direction of the second condensate water system. After absorbing heat through the second water-water heat exchanger, it enters the second condensate water system.

[0037] The high temperature of the flue gas provides heat for the thermal cycle of the original system and the adjacent unit. By recovering the heat of the boiler's exhaust gas, the heat loss of the boiler is reduced, the thermal efficiency of the boiler is improved, and the energy of using high-quality steam from the adjacent unit is reduced, the feed water temperature is increased, and the energy consumption during the startup process is reduced. At the same time, by using the original system, the investment is low, the recovery period is short, and the startup cost of the unit is reduced.

[0038] Further, before the steps S1 - S6, the hot water in the first interconnected heat medium water system of the first unit needs to enter the heat absorption module through the outlet pipe.

[0039] The beneficial effect of adopting the above further solution is that the high temperature of the flue gas in the heat absorption module is used to heat the cold water entering the heat absorption module, thereby forming hot water. Then, the hot water is used for circulating heating of the local unit and the adjacent unit.

[0040] Further, based on after the step S5,

[0041] The hot water entering the second interconnected heat medium water system returns to the first interconnected heat medium water system through the interconnected return water pipeline;

[0042] The hot water on the heat absorption side of the second condensate system enters the second deaerator.

[0043] The beneficial effect of adopting the above further solution is that by using the original system of the adjacent unit's waste heat recovery device, the adjacent unit heating system of the waste heat recovery system is put into operation, and the heat is transferred from the adjacent unit to the local unit's condensate system, and then flows into the deaerator. When the waste heat of the adjacent unit's flue gas is insufficient, the original auxiliary heating system can still be used to maintain the water supply temperature requirement during startup and save fuel. When this system is put into operation during startup, the heat of the boiler's exhaust gas can be effectively utilized, the heat loss of the boiler is reduced, the thermal efficiency of the boiler is improved, and the energy of using high-quality steam from the adjacent unit is reduced, the feed water temperature is increased, and the energy consumption during the startup process is reduced. At the same time, by using the original system, the investment is low, the recovery period is short, and the startup cost of the unit is reduced.

[0044] Further, when the second unit is operating and the first unit is stopped: the second unit supplies heat in the reverse direction to the first interconnected heat medium water system of the first unit.

[0045] The beneficial effects of adopting the above further solution are as follows: The first unit and the second unit operate individually. By utilizing the original system of the waste heat recovery device of the adjacent unit, only the operation mode of the unit is adjusted, without equipment transformation and additional investment. Meanwhile, during individual operation, when starting another unit, the adjacent unit heating system of the waste heat recovery system is put into operation, and the heat is transferred from the adjacent unit to the condensate system of this unit, and then flows into the deaerator. When the flue gas waste heat of the adjacent unit is insufficient, the original auxiliary heating system can still be used to maintain the water supply temperature requirement during startup, saving fuel. When this system is put into operation during startup, the waste heat of the boiler flue gas can be effectively utilized, reducing the heat loss of the boiler, improving the thermal efficiency of the boiler, reducing the energy consumption of using high-quality steam from the adjacent unit, increasing the feed water temperature, and reducing the energy consumption during the startup process. Meanwhile, by using the original system, the investment is low, the recovery period is short, and the startup cost of the unit is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 FIG. is a schematic structural diagram of an energy-saving device for unit startup according to the present invention;

[0047] Figure 2 FIG. is a schematic flow chart of an energy-saving method for unit startup according to the present invention.

[0048] In the drawings, the list of components represented by each reference numeral is as follows: 11. First interconnected heat medium water system; 111. Outlet pipe; 112. First regulating device; 12. Heat absorption module; 121. Recirculation pipeline; 122. First outlet pipe; 123. Interconnected water supply pipeline; 1231. Second regulating device; 124. Interconnected return water pipeline; 13. First heat exchange group; 131. First heat release branch; 132. Second heat release branch; 133. First heat release branch return water pipeline; 14. First water-water heat exchanger; 15. First condensate system; 151. Adjusting valve; 21. Second heat release branch water supply pipeline; 22. Second heat release branch return water pipeline; 23. Second interconnected heat medium water system; 24. Second water-water heat exchanger; 25. Second condensate system; 3. First deaerator; 4. Second deaerator. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0050] Example 1

[0051] As Figure 1As shown in the figure, a unit start-up energy-saving device includes a first unit, a second unit, a first deaerator 3 and a second deaerator 4. The interconnected water supply pipeline 123 of the first unit is connected to the second heat release branch water supply pipeline 21 of the second unit. The second heat release branch water supply pipeline 21 is connected to the second heat release branch return water pipeline 22. The second heat release branch return water pipeline 22 is connected to the interconnected return water pipeline 124. The first unit and the second unit are connected through the interconnected return water pipeline 124. The first unit is provided with the first deaerator 3, and the second unit is provided with the second deaerator 4.

[0052] Specifically, the flue gas generated by the first unit heats the cold water in the heat absorption module 12. Then, the hot water is supplied to the second heat release branch water supply pipeline 21 of the second unit through the interconnected water supply pipeline 123. The cold water generated by the first unit is returned to the first unit again through the interconnected return water pipeline 124 of the second unit, and the high temperature of the flue gas is used to provide heat for the heat cycle of the original system and the adjacent unit. The heat of the first unit or the second unit is transferred from the adjacent unit to the condensate system of this unit and flows into the first deaerator 3 or the second deaerator 4 for heat exchange.

[0053] As Figure 1 shown in the figure, the first unit includes a first interconnected heat medium water system 11, a heat absorption module 12, a first heat exchange group 13, a first water-water heat exchanger 14 and a first condensate system 15. The outlet pipe 111 of the interconnected heat medium water system 11 is connected to the flue gas cooler of the heat absorption module 12. The outlet pipelines of the heat absorption module 12 are respectively connected to the recirculation pipeline 121, the first heat release branch 131, the second heat release branch 132 and the interconnected water supply pipeline 123. The inlet pipeline of the first heat exchange group 13 is connected to the first heat release branch 131. The outlet pipeline of the first heat exchange group 13 is connected to the first heat release branch return water pipeline 133 and is connected to the interconnected heat medium water system 11 through the first heat release branch return water pipeline 133. The heat release side inlet pipeline of the first water-water heat exchanger 14 is connected to the second heat release branch 132. The heat release side outlet pipeline of the first water-water heat exchanger 14 is connected to the first interconnected heat medium water system 11. The heat absorption side pipeline of the heat absorption module 14 is connected to the first condensate system 15; the outlet pipeline of the heat absorption module 12 is connected to the first interconnected heat medium water system 11 through the recirculation pipeline 121; the outlet pipeline of the heat absorption module 12 is connected to the second heat release branch water supply pipeline 21 of the second unit through the interconnected water supply pipeline 123.

[0054] Specifically, two sets of identical units are in operation. When the first unit is operating, the flue gas flowing through the heat absorption module 12 heats the feed water to form hot water. At the same time, the hot water in the heat absorption module 12 is divided into four branches for circulating flow. When the hot water in the heat absorption module 12 enters the return pipe of the first heat release branch 133 through the recirculation pipe 121 and then enters the first interconnected heat transfer water system 11 through the return pipe of the first heat release branch 133; when the hot water in the heat absorption module 12 enters the first heat release branch 131 through the first water outlet pipe 122, then enters the first heat exchange group 13 through the first heat release branch 131, is heated through the first heat exchange group 13, and then returns to the first interconnected heat transfer water system 11 through the return pipe of the first heat release branch 133; when the hot water in the heat absorption module 12 enters the first water-water heat exchanger 14 through the second heat release branch 132 and then returns to the first interconnected heat transfer water system 11 through the outlet pipe of the first water-water heat exchanger 14; at the same time, the hot water in the heat absorption module 12 will also enter the supply pipe of the second heat release branch 21 of the second unit through the interconnected supply pipe 123 of the first unit, and then enter the second water-water heat exchanger 24 through the return pipe of the second heat release branch 22, and then enter the second interconnected heat transfer water system 23 and / or the second condensate system 25.

[0055] As Figure 1 shown, regulating valves 151 are provided at both the first condensate system 15 and the second condensate system 25 of the second unit;

[0056] The hot water of the first unit transfers heat to the first condensate system 15 through the first water-water heat exchanger 14;

[0057] The hot water of the second unit transfers heat to the second condensate system 25 through the second water-water heat exchanger 24.

[0058] Specifically, the steam generated by the adjacent unit enters the second condensate system 25 through heat exchange in the second water-water heat exchanger 24, and then the heat energy enters the second deaerator 4 through the second condensate system 25. The heated feed water is pumped to the boiler to absorb heat and cool the boiler, and the generated steam is used for turbine rotation. By providing a regulating valve 151 at the second condensate system 25, the condensate water temperature in the second condensate system 25 is adjusted according to the water supply temperature required by the boiler.

[0059] As Figure 1 shown, a first regulating device 112 is provided on the interconnected return pipe 124, and the first regulating device 112 regulates the connection or closing of the interconnected return pipe 124;

[0060] A second regulating device 1231 is provided on the interconnected supply pipe 123, and the second regulating device 1231 regulates the connection or closing of the interconnected supply pipe 123.

[0061] Specifically, when the first regulating device 112 is opened, the interconnected return water pipeline 124 of the first unit is communicated with the interconnected return water pipeline 124 of the second unit. When the first regulating device 112 is closed, the interconnected return water pipeline 124 of the first unit is not communicated with the interconnected return water pipeline 124 of the second unit.

[0062] When the second regulating device 1231 is opened, the interconnected supply water pipeline 123 of the first unit is communicated with the interconnected supply water pipeline 123 of the second unit. When the second regulating device 1231 is closed, the interconnected supply water pipeline 123 of the first unit is not communicated with the interconnected supply water pipeline 123 of the second unit.

[0063] The beneficial effects of this embodiment are as follows: The flue gas generated by the first unit heats the cold water in the heat absorption module 12. Then, the hot water is supplied to the second heat release branch supply water pipeline 21 of the second unit through the interconnected supply water pipeline 123, and the cold water after heat release returns to the first unit again through the interconnected return water pipeline 124 of the second unit, using the high temperature of the flue gas to provide heat for the thermal cycle of the original system and the adjacent unit. The heat of the first unit or the second unit is transferred from the adjacent unit to the condensate system of this unit and flows into the first deaerator 3 or the second deaerator 4 for heat exchange. The greater the heat exchange amount in the deaerator, the less heat generated by the fuel absorbed in the boiler, and thus the more fuel is saved. By recovering the waste heat of the boiler flue gas, the heat loss of the boiler is reduced, the thermal efficiency of the boiler is improved, and the energy consumption of using high-quality steam from the adjacent unit is reduced, the feed water temperature is increased, and the energy consumption during the startup process is reduced. At the same time, by using the original system, the investment is low, the recovery period is short, and the startup cost of the unit is reduced.

[0064] The working process of this embodiment is as follows: Two identical units are operating. When the first unit is operating, the flue gas flowing through the heat absorption module 12 heats the feed water to form hot water. At the same time, the hot water in the heat absorption module 12 is divided into four branches for circulating flow. When the hot water in the heat absorption module 12 enters the first heat release branch return water pipeline 133 through the recirculation pipeline 121 and then enters the first interconnected heat transfer medium water system 11 through the first heat release branch return water pipeline 133; when the hot water in the heat absorption module 12 enters the first heat release branch 131 through the first outlet pipe 122 and then enters the first heat exchange group 13 through the first heat release branch 131, is heated by the first heat exchange group 13, and then returns to the first interconnected heat transfer medium water system 11 through the first heat release branch return water pipeline 133; when the hot water in the heat absorption module 12 enters the first water-water heat exchanger 14 through the second heat release branch 132 and then returns to the first interconnected heat transfer medium water system 11 through the outlet pipeline of the first water-water heat exchanger 14; at the same time, the hot water in the heat absorption module 12 also enters the second heat release branch supply water pipeline 21 of the second unit through the interconnected supply water pipeline 123 of the first unit, then enters the second water-water heat exchanger 24 through the second heat release branch return water pipeline 22, and then enters the second interconnected heat transfer medium water system 23 and / or the second condensate system 25.

[0065] In this embodiment, the annual unit start-up times of the original thermal power plant were about five times, and now the annual unit start-up times are about twenty-five times, which can effectively save the energy consumption of unit start-up.

[0066] Embodiment 2

[0067] As Figure 1-2 shown, based on Embodiment 1, a unit start-up energy-saving method is as follows:

[0068] When the first unit is operating, the second unit stops operating, the first regulating device 112 and the second regulating device 1231 are opened, and the first interconnected hot medium water system 11 is connected to the second interconnected hot medium water system 23 of the second unit;

[0069] And / or, when the second unit is operating, the first unit stops operating, the first regulating device 112 and the second regulating device 1231 are opened, and the second unit is connected to the first interconnected hot medium water system 11 through the second interconnected hot medium water system 23.

[0070] Specifically, the first unit and the second unit operate independently. When starting another unit during independent operation, the heat is transferred from the adjacent unit to the condensate system of this unit, and then flows into the deaerator for use.

[0071] As Figure 1-2 shown, when the first unit and the second unit are operating simultaneously, the first regulating device 112 and the second regulating device 1231 are closed, and the first interconnected hot medium water system 11 of the first unit is not connected to the second interconnected hot medium water system 23 of the second unit; the second interconnected hot medium water system 23 of the second unit is not connected to the first interconnected hot medium water system 11.

[0072] Specifically, when the waste heat of the flue gas of the adjacent unit is insufficient, the first regulating device 112 and the second regulating device 1231 are closed, and the original auxiliary heating system is still used to maintain the water temperature requirement during start-up and save fuel.

[0073] As Figure 1-2 shown, a unit start-up energy-saving method, the energy-saving steps are as follows:

[0074] When the first unit is operating and the second unit stops operating:

[0075] S1: The cold water in the heat absorption module 12 absorbs the heat in the boiler flue gas to form hot water.

[0076] S2: The hot water in the heat absorption module 12 enters the first heat release branch return pipe 133 through the recirculation pipe 121, and then returns to the first interconnected hot medium water system 11 through the first heat release branch return pipe 133;

[0077] S3: The hot water in the heat absorption module 12 enters the first heat release branch 131 through the first water outlet pipe 122, then enters the first heat exchange group 13 through the first heat release branch 131, exchanges heat through the first heat exchange group 13, and then returns to the first interconnected heat medium water system 11 through the first heat release branch return water pipeline 133;

[0078] S4: The hot water in the heat absorption module 12 enters the first water-water heat exchanger 14 through the second heat release branch 132, and then returns to the first interconnected heat medium water system 11 through the water outlet pipeline of the first water-water heat exchanger 14;

[0079] S5: The hot water in the heat absorption module 12 enters the second heat release branch water supply pipeline 21 of the second unit through the interconnected water supply pipeline 123 of the first unit;

[0080] The hot water in the second heat release branch water supply pipeline 21 enters the second water-water heat exchanger 24 and returns to the first interconnected heat medium water system 11 through the second heat release branch return water pipeline 22 and the interconnected return water pipeline 124;

[0081] S6: The heat absorption side of the second water-water heat exchanger 24 is connected to the condensate from the second condensate system 15. After absorbing heat through the second water-water heat exchanger 24, it enters the second condensate system 15.

[0082] Steps S1, S2, S3, S4, S5, and S6 are respectively and independently reciprocally circulated.

[0083] Specifically, two sets of identical units operate. When the first unit operates, cold water in the heat absorption module 12 absorbs the heat from the boiler flue gas to form hot water. At the same time, the hot water in the heat absorption module 12 is divided into four branches for circulating flow. When the hot water in the heat absorption module 12 enters the first heat release branch return pipe 133 through the recirculation pipe 121, and then enters the interconnected heat medium water system through the first heat release branch return pipe 133; when the hot water in the heat absorption module 12 enters the first heat release branch 131 through the first outlet pipe 122, and then enters the first heat exchange group 13 through the first heat release branch 131, is heated through the first heat exchange group 13, then enters the first heat release branch return pipe 133 through the first heat exchange group 13, and then enters the first interconnected heat medium water system 11; when the hot water in the heat absorption module 12 enters the first water-water heat exchanger 14 through the second heat release branch 132, and then returns to the first interconnected heat medium water system 11 through the outlet pipe of the first water-water heat exchanger 14; at the same time, the hot water in the heat absorption module 12 will also enter the second heat release branch water supply pipe 21 of the second unit through the interconnected water supply pipe 123 of the first unit. Then, the hot water in the second heat release branch water supply pipe 21 enters the second water-water heat exchanger 24 through the second heat release branch return pipe 22, and then returns to the first interconnected heat medium water system 11 through the interconnected return pipe 124; the heat absorption side of the second water-water heat exchanger 24 is connected to the condensate water from the direction of the second condensate water system 15. After being absorbed by the second water-water heat exchanger 24, it enters the second condensate water system 15.

[0084] As Figure 1-2 shown, before steps S1 - S6, the cold water in the first interconnected heat medium water system 11 of the first unit needs to enter the heat absorption module 12 through the outlet pipe 111.

[0085] Specifically, the cold water entering the heat absorption module 12 is heated by the heat from the boiler flue gas to form hot water. Then, the recirculating water is used to supply heat to this unit and the adjacent unit in a cycle.

[0086] As Figure 1-2 shown, after step S5,

[0087] the hot water entering the second interconnected heat medium water system 23 returns to the first interconnected heat medium water system 11 through the interconnected return pipe 124;

[0088] the hot water on the heat absorption side of the second condensate water system 25 enters the second deaerator 4.

[0089] Specifically, the hot water in the heat absorption module 12 enters the second heat release branch water supply pipeline 21 of the second unit through the interconnected water supply pipeline 123 of the first unit. The hot water in the second heat release branch water supply pipeline 21 enters the second water-water heat exchanger 24 through the second heat release branch return water pipeline 22. Then, the hot water in the second water-water heat exchanger 24 first passes through the second heat release branch return water pipeline 22, then through the interconnected return water pipeline 124, and finally returns to the first interconnected heat medium water system 11.

[0090] As Figure 1-2 shown, when the second unit is operating and the first unit is stopped: The second unit supplies heat in the reverse direction to the first interconnected heat medium water system 11 of the first unit.

[0091] Specifically, the first unit and the second unit operate individually. By utilizing the original system of the adjacent unit waste heat recovery device, only the operation mode of the unit is adjusted, without equipment modification and no additional investment is required. At the same time, during individual operation, when starting another unit, the adjacent unit heating system of the waste heat recovery system is put into operation, and the heat is transferred from the adjacent unit to the condensate system of this unit, and then flows into the deaerator. When the flue gas waste heat of the adjacent unit is insufficient, the original auxiliary heating system can still be utilized to maintain the water supply temperature requirement during startup, saving fuel oil. When this system is put into operation during startup, the heat of the boiler flue gas can be effectively utilized, reducing the heat loss of the boiler, improving the thermal efficiency of the boiler, and reducing the energy consumption of using high-quality steam from the adjacent unit, increasing the feed water temperature, and reducing the energy consumption during the startup process. At the same time, by utilizing the original system, the investment is low, the recovery period is short, and the startup cost of the unit is reduced.

[0092] The beneficial effects of this embodiment are as follows: The flue gas generated by the first unit heats the cold water in the heat absorption module 12. Then, the hot water is supplied to the second heat release branch water supply pipeline 21 of the second unit through the interconnected water supply pipeline 123, and the cold water generated by the first unit returns to the first unit again through the interconnected return water pipeline 124 of the second unit, using the high temperature of the flue gas to provide heat for the heat cycle of the original system and the adjacent unit. The heat of the first unit or the second unit is transferred from the adjacent unit to the condensate system of this unit and flows into the first deaerator 3 or the second deaerator 4 for heat exchange. The greater the heat exchange amount in the deaerator, the less heat generated by the fuel oil absorbed in the boiler, and thus the more fuel oil is saved. By recovering the heat of the boiler flue gas, the heat loss of the boiler is reduced, the thermal efficiency of the boiler is improved, and the energy consumption of using high-quality steam from the adjacent unit is reduced, the feed water temperature is increased, and the energy consumption during the startup process is reduced. At the same time, by utilizing the original system, the investment is low, the recovery period is short, and the startup cost of the unit is reduced.

[0093] The working process of this embodiment is as follows: Two identical units operate. When the first unit operates, the cold water in the heat absorption module 12 is heated. At the same time, the hot water in the heat absorption module 12 is divided into four branches for circulating flow. When the first unit does not need to supply heat, the hot water in the heat absorption module 12 enters the first heat release branch return pipe 133 through the recirculation pipe 121, and then enters the first interconnected heat medium water system 11 through the first heat release branch return pipe 133; when the first unit needs to supply heat, the hot water in the heat absorption module 12 enters the first heat release branch 131 through the first water outlet pipe 122, and then enters the first heat exchange group 13 through the first heat release branch 131, is heated through the first heat exchange group 13, then enters the first heat release branch return pipe 133 through the first heat exchange group 13, and then enters the first water-water heat exchanger 14 or enters the first interconnected heat medium water system 11; when the first heat exchange group 13 does not need to work, the hot water in the heat absorption module 12 enters the first water-water heat exchanger 14 through the second heat release branch 132, the water outlet of the first water-water heat exchanger 14 enters the first condensate system 15, enters the first deaerator 3 through the first condensate system 15, and supplies heat to the steam turbine through the first deaerator 3; at the same time, the hot water in the heat absorption module 12 also enters the second heat release branch water supply pipe 21 of the second unit through the interconnected water supply pipe 123 of the first unit, then enters the interconnected return pipe 124 through the second heat release branch return pipe 22, and enters the first interconnected heat medium water system 11 of the first unit, and circulates in this way.

[0094] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0095] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0096] In the present invention, unless otherwise clearly specified or limited, terms such as "installed", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0097] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely means that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely means that the first feature has a lower horizontal height than the second feature.

[0098] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0099] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A unit startup energy-saving device, characterized in that: The invention comprises a first unit, a second unit, a first deaerator (3) and a second deaerator (4); the interconnected water supply pipeline (123) of the first unit is connected to the second heat release branch water supply pipeline (21) of the second unit; the second heat release branch water supply pipeline (21) is connected to the second heat release branch return pipeline (22); the second heat release branch return pipeline (22) is connected to the interconnected return pipeline (124); the first unit and the second unit are connected via the interconnected return pipeline (124); the first unit is provided with the first deaerator (3) and the second unit is provided with the second deaerator (4).

2. The unit startup energy-saving device according to claim 1, characterized in that: The first unit and the second unit have the same structure. The first unit comprises a first interconnected heat medium water system (11), a heat absorption module (12), a first heat exchange group (13), a first water-to-water heat exchanger (14) and a first condensing water system (15); the outlet pipe (111) of the interconnected heat medium water system (11) is connected to the flue gas cooler of the heat absorption module (12); the outlet pipe of the heat absorption module (12) is respectively connected to the recirculation pipeline (121), the first heat release branch (131), the second heat release branch (132) and the interconnected water supply pipeline (123); the water inlet pipe of the first heat exchange group (13) is connected to the first heat release branch (131); the outlet pipe of the first heat exchange group (13) is connected to the return water pipe (133) of the first heat release branch; and The interconnected heat medium water system (11) is connected via a first heat release branch return water pipeline (133); the heat release side water inlet pipeline of the first water-to-water heat exchanger (14) is connected to the second heat release branch (132); the heat release side water outlet pipeline of the first water-to-water heat exchanger (14) is connected to the first interconnected heat medium water system (11); the heat absorption side pipeline of the first water-to-water heat exchanger (14) is connected to the first condensation system (15); the outlet pipeline of the heat absorption module (12) is connected to the first interconnected heat medium water system (11) via a recirculation pipeline (121); and the outlet pipeline of the heat absorption module (12) is connected to the second heat release branch water supply pipeline (21) of the second unit via an interconnected water supply pipeline (123).

3. A unit startup energy-saving device according to claim 2, characterized in that: The first condensate system (15) and the second condensate system (25) of the second unit are both provided with an adjustment valve (151); The hot water of the first unit exchanges heat with the first condensing system (15) through the first water-to-water heat exchanger (14); The hot water of the second unit exchanges heat with the second condensing system (25) through the second water-to-water heat exchanger (24).

4. The unit startup energy-saving device according to claim 3, characterized in that: The interconnected water return pipeline (124) is provided with a first regulating device (112), and the first regulating device (112) regulates the connection or closing of the interconnected water return pipeline (124); The interconnected water supply pipeline (123) is provided with a second regulating device (1231), and the second regulating device (1231) regulates the connection or closing of the interconnected water supply pipeline (123).

5. A unit startup energy-saving method, characterized in that: Based on the energy-saving device for starting a unit according to claim 4, the energy-saving method is: when the first unit is running, the second unit stops running, the first regulating device (112) and the second regulating device (1231) are turned on, and the first interconnected heat medium water system (11) is connected to the second interconnected heat medium water system (23) of the second unit; And / or, when the second unit is in operation, the first unit is stopped, the first regulating device (112) and the second regulating device (1231) are opened, and the second unit is connected to the first interconnected heat medium water system (11) through the second interconnected heat medium water system (23).

6. A unit startup energy-saving method according to claim 5, characterized in that: When the first unit and the second unit are operated simultaneously, the first regulating device (112) and the second regulating device (1231) are closed, the first interconnected heat medium water system (11) and the second interconnected heat medium water system (23) are not connected; the second interconnected heat medium water system 23 of the second unit is not connected to the first interconnected heat medium water system 11.

7. A unit startup energy-saving method according to claim 5, characterized in that: The steps to save energy are: The first unit is running and the second unit is stopped: S1: The cold water in the heat absorption module (12) absorbs the heat in the boiler exhaust gas to form hot water; S2: The hot water in the heat absorption module (12) enters the first heat release branch water return pipeline (133) through the recirculation pipeline (121), and then returns to the first interconnected heat medium water system (11) through the first heat release branch water return pipeline (133); S3: The hot water in the heat absorption module (12) enters the first heat release branch (131) through the first water outlet pipe (122), then enters the first heat exchange group (13) through the first heat release branch (131), exchanges heat through the first heat exchange group (13), and then returns to the first interconnected heat medium water system (11) through the first heat release branch return pipe (133); S4: The hot water in the heat absorption module (12) enters the first water-to-water heat exchanger (14) through the second heat release branch (132), and then returns to the first interconnected heat medium water system (11) through the outlet pipe of the first water-to-water heat exchanger (14); S5: The hot water in the heat absorption module (12) enters the second heat release branch water supply pipeline (21) of the second unit through the interconnected water supply pipeline (123) of the first unit; The hot water in the second heat release branch water supply pipeline (21) enters the second water-to-water heat exchanger (24), and returns to the first interconnected heat medium water system (11) through the second heat release branch water return pipeline (22) and the interconnected water return pipeline (124); S6: The heat absorption side of the second water-to-water heat exchanger (24) is connected to the condensed water from the second condensed water system (151), and after absorbing heat in the second water-to-water heat exchanger (24), the condensed water enters the second condensed water system (25); In this way, steps S1, S2, S3, S4, S5 and S6 are cycled back and forth independently.

8. A unit startup energy-saving method according to claim 7, characterized in that: Before steps S1 to S6, the hot water in the first interconnected heat medium water system (11) of the first unit needs to be transported to the heat absorption module (12) through the water outlet pipe (111).

9. A unit startup energy-saving method according to claim 7, characterized in that: Based on step S5, The hot water entering the second interconnected heat medium water system (21) returns to the first interconnected heat medium water system (11) through the interconnected return water pipeline (124); The hot water on the heat absorption side of the second condensation system (25) enters the second deaerator (4).

10. A unit startup energy-saving method according to claim 9, characterized in that: When the second unit is running and the first unit is stopped, the second unit reversely supplies heat to the first interconnected heat medium water system (11) of the first unit.

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