Waste incineration power generation system coupled with solar energy

Abstract

The present invention discloses a waste incineration power generation system coupled with solar energy, which belongs to the field of energy utilization technology. It includes: a waste incineration power generation system, a solar power generation system, a steam turbine power generation system, a feedwater heating system, which includes two feedwater circulation branches, a reheating system, which includes two steam circulation branches and an energy cascade utilization heating condensate system, which includes two condensate circulation branches. The present invention couples solar thermal power generation with waste incineration power generation, and combines the intermediate primary reheating technology to achieve cascade utilization of energy, improve power generation efficiency, reduce power generation costs, and help the industry achieve carbon peak and carbon neutrality goals as soon as possible.

Description

Technical Field

[0001] The invention belongs to the technical field of energy utilization, and in particular relates to a waste incineration power generation system coupled with solar energy. Background Art

[0002] The rapid development of solar thermal power generation technology has attracted worldwide attention. However, a single solar thermal power generation system is prone to frequent start-stop and load fluctuations, which will affect the power generation efficiency and safe operation life cycle of the unit, leading to problems such as excessively high power generation costs and unstable operation. Therefore, the development of solar thermal is limited. If solar energy is integrated into coal-fired power generation, biomass power generation, garbage power generation and other units, and thermal complementary power generation of solar energy and coal, biomass and other energy sources is carried out, a new solar thermal power generation system can be developed, which can solve the problems of unstable solar energy utilization and high cost.

[0003] Patent CN 101787906 A discloses a solar energy and biomass energy comprehensive complementary combined thermal power generation system, which realizes the coupling of biomass circulating fluidized bed boiler power generation system and solar energy. However, this technical solution does not use the primary reheating technology and fails to fully realize the cascade utilization of solar energy.

[0004] At present, domestic waste incineration power plants generally use medium-temperature and medium-pressure (4MPa, 400℃) main steam parameters, with a total thermal efficiency of only about 21%, and a power generation capacity of only 300-400kWh per ton of waste. As the emission standards for waste incineration pollutants become increasingly stringent, power plants have improved their flue gas purification systems by adding and updating flue gas purification equipment, resulting in higher and higher operating costs, and the profit margins of waste incineration power plants have been increasingly compressed. Faced with the above challenges, waste incineration companies are faced with the urgent need to increase their income from grid-connected power generation, make waste incineration projects sustainable, and improve the economic benefits of power plants. Intermediate reheating is a mature technology used in thermal power plants, including primary reheating and secondary reheating, and is widely used to improve cycle thermal efficiency. The steam that has done work in the high-pressure part of the turbine is drawn out from the turbine and sent to the boiler's reheater for reheating. After the steam temperature is increased, it is then drawn back into the low-pressure part of the turbine to continue expanding and doing work. Every 10°C increase in the reheat temperature can increase the thermal efficiency of the reheat cycle by 0.2% to 0.3%, which can significantly improve the economic benefits of the power plant.

[0005] Therefore, under the development goals and vision of "carbon peak and carbon neutrality", there is great potential for vigorously promoting energy supply-side reform and the coordinated coupling development of renewable energy; at the same time, under the high-pressure situation of increasingly stringent environmental protection requirements, if waste incineration companies want to obtain economic benefits and improve their market competitiveness, technological innovation is imperative. Summary of the invention

[0006] Technical problems solved: In response to the above technical problems, the present invention provides a waste incineration power generation system coupled with solar energy, which couples solar thermal power generation with waste incineration power generation, and combines it with intermediate primary reheating technology. It can realize the cascade utilization of energy, improve power generation efficiency, reduce power generation costs, and help the industry achieve carbon peak and carbon neutrality goals as soon as possible.

[0007] Technical solution: A waste incineration power generation system coupled with solar energy, which includes:

[0008] A waste incineration power generation system, comprising a boiler and a steam drum, an economizer, a reheater and a superheater arranged on the boiler;

[0009] A solar power generation system, comprising a solar collector and a thermal oil-water heat exchanger connected by a thermal oil circulation pipeline;

[0010] A steam turbine power generation system, comprising a steam turbine high-pressure cylinder, a steam turbine low-pressure cylinder, a condenser, a first-stage low-pressure heater, a second-stage low-pressure heater, a deaerator and a feedwater pump connected in sequence;

[0011] The feedwater heating system includes two feedwater circulation branches: branch one from the feedwater pump, economizer, steam drum to the high-pressure cylinder of the steam turbine and branch two from the feedwater pump, heat transfer oil-water heat exchanger, superheater to the high-pressure cylinder of the steam turbine;

[0012] The reheat system includes two steam circulation branches: branch A from the high-pressure cylinder of the steam turbine, the reheater to the low-pressure cylinder of the steam turbine, and branch B from the high-pressure cylinder of the steam turbine, the heat transfer oil-water heat exchanger to the low-pressure cylinder of the steam turbine;

[0013] The energy cascade heating condensate system includes two condensate circulation branches: branch A from the first-level low-pressure heater, the second-level low-pressure heater to the deaerator, and branch B from the first-level low-pressure heater, the thermal oil-water heat exchanger to the deaerator.

[0014] Preferably, the solar thermal collector is a trough solar thermal collector.

[0015] Preferably, a circulating water pump is provided between the condenser and the first-stage low-pressure heater.

[0016] Preferably, a generator is connected to the low-pressure cylinder of the steam turbine.

[0017] Preferably, in the branch A and the branch B, the reheating temperature of the steam is 370-380°C.

[0018] Preferably, in the second branch, the temperature of the thermal oil in the thermal oil-water heat exchanger is 320-330°C.

[0019] Preferably, in the branch B, the temperature of the thermal oil in the thermal oil-water heat exchanger is 290-300°C.

[0020] Preferably, the boiler is a waste incineration waste heat boiler, and its main steam parameters are 4 MPa, 400°C or 6.4 MPa, 450°C.

[0021] Beneficial effects: The present invention couples the solar thermal absorption and conversion system to the current waste incineration power plant. The solar concentrating and collecting device is arranged on the roof, wall or surrounding open space of the waste incineration power plant, which can save the space occupied by the concentrating equipment and realize the maximum utilization of resources.

[0022] The present invention integrates solar energy into the waste incineration waste heat boiler, uses solar energy and domestic waste as input energy, and generates electricity through coupling when the solar radiation is sufficient; it is disconnected on rainy days, and the waste incineration system generates electricity by itself, ensuring the stable, safe and continuous operation of the system. In addition, it does not emit additional CO2, which is in line with the current environmental protection concept of "carbon peak and carbon neutrality", and embodies technical, economic and energy-saving advantages;

[0023] The present invention uses the intermediate one-time reheating technology, the main steam parameters are set to the normal atmospheric pressure 4MPa / 400℃ or the high parameters 6.4MPa / 450℃, the reheating temperature is set to 370~380℃, the exhaust steam after the steam works is heated in the heating surface of the waste heat boiler or the thermal oil-water heat exchanger to form superheated steam, and then enters the low-pressure cylinder of the steam turbine again to continue to work and generate electricity. Therefore, the energy stored in the thermal oil-water heat exchanger by solar energy and the heat of the waste heat furnace of the waste incineration can be used, combined with the one-time reheating technology, so that the power generation capacity of the unit is greatly increased, reflecting huge technical advantages;

[0024] The present invention utilizes solar energy in a cascade manner. The heat transfer oil after heating the power plant feed water continues to heat part of the condensate, which can displace part of the low-pressure extraction steam or deaerator extraction steam, further improving the power generation capacity of the unit, reflecting huge technical advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the waste incineration power generation system coupled with solar energy of the present invention;

[0026] The numbers in the figure represent the following: 1. Boiler; 2. Solar collector; 3. Thermal oil circulation pipeline; 4. Economizer; 5. Steam drum; 6. Thermal oil-water heat exchanger; 7. Superheater; 8. Steam turbine; 9. Reheater; 10. Generator; 11. Condenser; 12. Circulating water pump; 13. Low-pressure heater; 14. Deaerator; 15. Feed water pump; 81. Steam turbine high-pressure cylinder; 82. Steam turbine low-pressure cylinder; 131. First-stage low-pressure heater; 132. Second-stage low-pressure heater. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] like Figure 1 As shown, the waste incineration power generation system coupled with solar energy comprises:

[0030] A waste incineration power generation system, comprising a boiler 1 and a steam drum 5, an economizer 4, a reheater 9 and a superheater 7 arranged on the boiler 1;

[0031] A solar power generation system, comprising a solar collector 2 and a thermal oil-water heat exchanger 6 connected by a thermal oil circulation pipeline 3; wherein the thermal oil-water heat exchanger 6 is provided with three groups, numbered as thermal oil-water heat exchanger (I), thermal oil-water heat exchanger (II) and thermal oil-water heat exchanger (III);

[0032] The steam turbine power generation system includes a steam turbine high-pressure cylinder 81, a steam turbine low-pressure cylinder 82, a condenser 11, a first-stage low-pressure heater 131, a second-stage low-pressure heater 132, a deaerator 14, and a feedwater pump 15 connected in sequence; the steam turbine low-pressure cylinder 82 is also connected to a generator 10;

[0033] The feedwater heating system includes two feedwater circulation branches: a branch 1 from the feedwater pump 15, economizer 4, steam drum 5 to the high-pressure cylinder 81 of the steam turbine, and a branch 2 from the feedwater pump 15, thermal oil-water heat exchanger 6, superheater 7 to the high-pressure cylinder 81 of the steam turbine;

[0034] The reheat system includes two steam circulation branches: branch A from the high-pressure cylinder 81 of the steam turbine, the reheater 9 to the low-pressure cylinder 82 of the steam turbine, and branch B from the high-pressure cylinder 81 of the steam turbine, the heat transfer oil-water heat exchanger 6 to the low-pressure cylinder 82 of the steam turbine;

[0035] The energy ladder utilizes the heating condensate system, which includes two condensate circulation branches: branch A from the first-level low-pressure heater 131, the second-level low-pressure heater 132 to the deaerator 14, and branch B from the first-level low-pressure heater 131, the thermal oil-water heat exchanger 6 to the deaerator 14.

[0036] The process is as follows:

[0037] Step 1: The feed water enters the low-temperature economizer 4 at the tail end of the waste heat boiler 1 through the feed water pump 15 for heating, and then enters the steam drum 5 of the waste heat boiler 1 after heating, and then returns to the steam drum 5 for steam-water separation after being heated by the water-cooled wall;

[0038] Step 2: Another part of the feed water enters the thermal oil-water heat exchanger (I), and is heated into saturated steam by the thermal oil carrying solar heat in the thermal oil-water heat exchanger 6;

[0039] Step 3: The saturated steam heated by the heat transfer oil-water heat exchanger 6 is mixed with the saturated steam after steam-water separation in the steam drum 5, and enters the superheater 7 on the horizontal flue for superheating. The superheated steam after the outlet of the superheater 7 enters the high-pressure cylinder 81 of the steam turbine to generate electricity and do work;

[0040] Step 4: The exhaust steam from the high-pressure cylinder 81 of the steam turbine returns to the reheater 9 on the horizontal flue for reheating, and the temperature is raised to about 380°C. Another part of the exhaust steam enters the heat transfer oil-water heat exchanger (II) for reheating, and the temperature is raised to 370-380°C.

[0041] Step 5: The two parts of reheated steam are mixed and enter the low-pressure cylinder 82 of the steam turbine to expand and perform work, thereby driving the generator 10 to generate electricity;

[0042] Step 6: The exhaust steam of the steam turbine 8 enters the condenser 11, and after condensation, is sent to the two-stage low-pressure heater 13 through the circulating water pump 12 for heating to increase the condensate water temperature;

[0043] Step 7: extract part of the condensate from the outlet of the first-stage low-pressure heater 131 and send it to the heat transfer oil-water heat exchanger (III), and use the heat transfer oil after heat exchange to further increase the condensate temperature. The condensate returns to the outlet of the second-stage low-pressure heater 132 and enters the deaerator 14 for deoxidation;

[0044] Step 8: The heat transfer oil in the heat transfer oil water heat exchanger (I / II / III) returns to the solar collector 2 after heat exchange, absorbs solar heat and repeats the above heat exchange process;

[0045] Step 9: After deoxygenation, the feed water is sent to the economizer 4 and the thermal oil-water heat exchanger (I) for heating through the feed water pump 15, and the above steam-water process is repeated.

[0046] This process system utilizes solar energy in a cascaded manner. The heat transfer oil used to heat the power plant feed water continues to heat part of the condensate, which can replace part of the low-pressure steam extraction or deaerator steam extraction, further increasing the unit's power generation capacity, reflecting great technical advantages.

[0047] Example 2

[0048] On the basis of Example 1, the solar collector 2 adopts a trough-type solar collector and is arranged on the roof, between walls or in open areas around the waste incineration power plant, thereby saving space occupied by the focusing equipment and maximizing resource utilization.

[0049] This process system integrates solar energy into the waste incineration waste heat boiler, uses solar energy and domestic waste as input energy, and couples it to generate electricity when solar radiation is sufficient. It is decoupled on rainy days and the waste incineration system generates electricity on its own, ensuring stable, safe and continuous operation of the system. In addition, it does not emit additional CO2, which is in line with the current environmental protection concept of "carbon peak and carbon neutrality" and embodies technical, economic and energy-saving advantages.

[0050] Example 3

[0051] On the basis of Example 1, the main steam parameters of boiler 1, i.e., the waste incineration waste heat furnace, are set to 4 MPa, 400°C or 6.4 MPa, 450°C; in branch A and branch B, the reheat temperature of the steam is 370~380°C; in branch two, the temperature of the thermal oil in the thermal oil-water heat exchanger 6 is 320~330°C; in branch B, the temperature of the thermal oil in the thermal oil-water heat exchanger 6 is 290~300°C.

[0052] This process system makes full use of the intermediate reheat technology. The main steam parameters can be set to medium parameters of 4MPa / 400℃ or high parameters of 6.4MPa / 450℃. The steam reheat temperature can reach 370~380℃. The steam work capacity is enhanced and the unit power generation capacity is greatly increased, reflecting huge technical advantages.

Claims

1. A waste incineration power generation system coupled with solar energy, characterized in that: It includes: A waste incineration power generation system, comprising a boiler (1) and a steam drum (5), an economizer (4), a reheater (9) and a superheater (7) arranged on the boiler (1); A solar power generation system, comprising a solar collector (2) and a thermal oil-water heat exchanger (6) connected via a thermal oil circulation pipeline (3); A steam turbine power generation system, comprising a steam turbine high-pressure cylinder (81), a steam turbine low-pressure cylinder (82), a condenser (11), a first-stage low-pressure heater (131), a second-stage low-pressure heater (132), a deaerator (14), and a feedwater pump (15) connected in sequence; A feedwater heating system, comprising two feedwater circulation branches: a branch line 1 from a feedwater pump (15), an economizer (4), a steam drum (5) to a high-pressure cylinder (81) of a steam turbine, and a branch line 2 from a feedwater pump (15), a heat transfer oil-water heat exchanger (6), a superheater (7) to a high-pressure cylinder (81) of a steam turbine; The reheat system comprises two steam circulation branches: branch A from the high-pressure cylinder (81) of the steam turbine and the reheater (9) to the low-pressure cylinder (82) of the steam turbine, and branch B from the high-pressure cylinder (81) of the steam turbine and the heat transfer oil-water heat exchanger (6) to the low-pressure cylinder (82) of the steam turbine; The energy cascade utilization heating condensate system comprises two condensate circulation branches: branch A from the first-stage low-pressure heater (131), the second-stage low-pressure heater (132) to the deaerator (14) and branch B from the first-stage low-pressure heater (131), the thermal oil-water heat exchanger (6) to the deaerator (14).

2. The solar-coupled waste incineration power generation system according to claim 1 is characterized in that: The solar thermal collector (2) is a trough type solar thermal collector.

3. The solar-coupled waste incineration power generation system according to claim 1, characterized in that: A circulating water pump (12) is provided between the condenser (11) and the first-stage low-pressure heater (131).

4. The solar-coupled waste incineration power generation system according to claim 1, characterized in that: The steam turbine low-pressure cylinder (82) is connected to a generator (10).

5. The solar-coupled waste incineration power generation system according to claim 1, characterized in that: In the branch A and branch B, the reheat temperature of the steam is 370~380℃.

6. The solar-coupled waste incineration power generation system according to claim 1, characterized in that: In the second branch, the temperature of the heat transfer oil in the heat transfer oil-water heat exchanger (6) is 320-330°C.

7. The solar-coupled waste incineration power generation system according to claim 1, characterized in that: In the branch B, the temperature of the heat transfer oil in the heat transfer oil-water heat exchanger (6) is 290-300°C.

8. The solar-coupled waste incineration power generation system according to claim 1, characterized in that: The boiler (1) is a waste incineration waste heat boiler, and its main steam parameters are 4 MPa, 400°C or 6.4 MPa, 450°C.

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