Middle-temperature and medium-pressure reheating system for waste incineration power generation

Abstract

The utility model discloses a waste incineration power generation medium-temperature medium-pressure reheating system which comprises a waste heat boiler, a steam turbine, a steam reheater and a drainage pump, and the steam turbine comprises a steam turbine high-pressure cylinder and a steam turbine low-pressure cylinder. Wherein a main steam opening of the waste heat boiler conveys superheated steam to a main steam inlet of the steam turbine high-pressure cylinder, a steam pocket saturated steam opening of the waste heat boiler conveys saturated steam to the steam reheater, and a steam exhaust opening of the steam turbine high-pressure cylinder is connected with the steam reheater; the steam reheater heats exhaust steam of the steam turbine high-pressure cylinder through saturated steam extracted by the waste heat boiler drum and outputs the exhaust steam to the steam turbine low-pressure cylinder, a condensate water outlet of the steam reheater is connected with the drainage pump, and the drainage pump conveys condensate water exhausted by the steam reheater to the waste heat boiler. On the basis of an existing medium-temperature medium-pressure thermodynamic system, on the premise that the main steam temperature and pressure of the medium-temperature medium-pressure thermodynamic system are not increased, the steam reheater heats steam exhausted by the high-pressure cylinder of the steam turbine through saturated steam of the waste heat boiler drum, so that the power generation efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste incineration, and particularly to an intermediate temperature and intermediate pressure reheating system for waste incineration power generation. Background Art

[0002] In thermal power plants, increasing the steam inlet parameters of steam turbines is an effective way to improve the power generation efficiency of waste incineration power plants. Under the same conditions, the power generation of projects with intermediate temperature and sub-high pressure parameters generally increases by 8% compared with that of projects with intermediate temperature and intermediate pressure parameters. In the waste incineration power generation industry, the main factors hindering the improvement of steam parameters are high-temperature corrosion and wear problems on the flue gas side. At present, the industry mainly adopts measures such as surfacing welding and using better materials to extend the replacement cycle of corroded components, so as to obtain higher main steam temperature and power generation efficiency. Therefore, the development trend of the industry is that the parameters are getting higher and higher.

[0003] Theoretically, existing intermediate temperature and intermediate pressure projects can increase economic benefits by technically modifying to improve the main steam parameters. This method is mainly achieved by replacing the waste heat boiler, steam turbine, main steam, main feed water system, etc. However, in the implementation process, problems such as high technical modification costs of equipment and systems and long recovery periods of investment costs will be faced. The technical modification requires shutdown for construction and has a long cycle, during which the economic losses are large. The lack of a place to dispose of waste also has a negative social impact on the enterprise. The above factors have led to the fact that although the application of intermediate temperature and sub-high pressure parameters in the industry is quite mature, few early-established intermediate temperature and intermediate pressure projects improve economic benefits by increasing parameters.

[0004] Therefore, for these existing intermediate temperature and intermediate pressure waste incineration boiler systems, a technical modification method is needed to optimize the thermal cycle to improve power generation efficiency and economic benefits without changing the main steam parameters. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides an intermediate temperature and intermediate pressure reheating system for waste incineration power generation, which is based on the existing intermediate temperature and intermediate pressure waste incineration boiler system to improve power generation efficiency and economic benefits.

[0006] The intermediate temperature and intermediate pressure reheating system for waste incineration power generation according to an embodiment of the present invention includes a waste heat boiler, a steam turbine, a steam reheater, and a drain pump. The steam turbine includes a high-pressure cylinder of the steam turbine and a low-pressure cylinder of the steam turbine, wherein:

[0007] The main steam port of the waste heat boiler conveys superheated steam to the main steam inlet of the high-pressure cylinder of the steam turbine. The saturated steam port of the steam drum of the waste heat boiler conveys saturated steam to the steam reheater. The exhaust port of the high-pressure cylinder of the steam turbine is connected to the steam reheater. The steam reheater reheats the exhaust steam of the high-pressure cylinder of the steam turbine by using the saturated steam extracted from the steam drum of the waste heat boiler and outputs it to the low-pressure cylinder of the steam turbine. The condensate outlet of the steam reheater is connected to the condensate pump, and the condensate pump conveys the condensate discharged from the steam reheater to the waste heat boiler for reheating and evaporation again.

[0008] The medium-temperature and medium-pressure reheat system for waste incineration power generation according to the embodiment of the present invention has at least the following beneficial effects: Based on the existing medium-temperature and medium-pressure thermal system, without increasing the main steam temperature and pressure, the steam reheater uses the saturated steam of the steam drum of the waste heat boiler to heat the exhaust steam of the high-pressure cylinder of the steam turbine, so that it enters the low-pressure cylinder of the steam turbine at a higher temperature to improve the power generation efficiency.

[0009] According to some embodiments of the present invention, the medium-temperature and medium-pressure reheat system for waste incineration power generation further includes a low-pressure heater, and the low-pressure heater is connected to the extraction port of the low-pressure cylinder of the steam turbine. The steam extracted from the low-pressure cylinder of the steam turbine exchanges heat with the condensate water in the low-pressure heater.

[0010] According to some embodiments of the present invention, the medium-temperature and medium-pressure reheat system for waste incineration power generation further includes a condenser and a condensate pump. The drain port of the low-pressure heater is connected to the condenser. The condenser condenses the exhaust steam of the low-pressure cylinder of the steam turbine, and the condensate pump conveys the condensate water in the condenser to the low-pressure heater to heat the condensate water.

[0011] According to some embodiments of the present invention, the medium-temperature and medium-pressure reheat system for waste incineration power generation further includes a deaerator. The condensate water outlet of the low-pressure heater is connected to the deaerator. The deaerator is used to remove oxygen and other non-condensable gases in the boiler feed water, and the water outlet of the deaerator supplies feed water to the waste heat boiler.

[0012] According to some embodiments of the present invention, the medium-temperature and medium-pressure reheat system for waste incineration power generation further includes a boiler feed water pump. The boiler feed water pump is connected to the water outlet of the deaerator and conveys the boiler feed water to the waste heat boiler for the next heat cycle.

[0013] According to some embodiments of the present invention, the temperature of the steam conveyed from the waste heat boiler to the high-pressure cylinder of the steam turbine is 380 to 470 °C, and the steam pressure is 3.43 to 5.3 MPa.

[0014] According to some embodiments of the present invention, the steam temperature of the waste heat boiler delivered to the steam reheater is 253 to 274 °C, and the steam pressure is 4.18 to 5.8 MPa.

[0015] According to some embodiments of the present invention, the steam temperature of the high-pressure cylinder of the steam turbine delivered to the steam reheater is 160 to 200 °C, and the steam pressure is 0.45 to 0.8 MPa.

[0016] According to some embodiments of the present invention, the steam temperature of the steam reheater delivered to the low-pressure cylinder of the steam turbine is 240 to 270 °C, and the steam pressure is 0.4 to 0.8 MPa.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description, will become apparent in part from the following description, or will be learned through the practice of the present invention. Description of the Drawings

[0018] The present invention will be further described below in conjunction with the drawings and embodiments, where:

[0019] Figure 1 It is a connection schematic diagram of the medium-temperature and medium-pressure reheating system for waste incineration power generation in the embodiment of the present invention.

[0020] Reference numerals: 100 - waste heat boiler, 200 - steam turbine, 210 - high-pressure cylinder of the steam turbine, 220 - low-pressure cylinder of the steam turbine, 300 - steam reheater, 400 - drain pump, 500 - low-pressure heater, 600 - condenser, 700 - condensate pump, 800 - deaerator, 900 - boiler feed pump. Detailed Embodiments

[0021] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0022] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as up, down, front, back, left, right, 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 thus should not be construed as a limitation of the present invention.

[0023] In the description of the present invention, "several" means more than one, "multiple" means more than two, and understandings such as "greater than", "less than", "exceeding", etc. do not include the base number, while understandings such as "above", "below", "within", etc. include the base number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0024] In the description of the present invention, unless otherwise clearly defined, words such as "set", "installed", "connected", etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0025] In the description of the present invention, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. means 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 expressions 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.

[0026] In a thermal power plant, increasing the steam inlet parameters of a steam turbine is an effective way to improve the power generation efficiency of a waste incineration power plant. Under the same conditions, the power generation of a medium-temperature sub-high-pressure parameter project generally increases by 8% compared with that of a medium-temperature medium-pressure parameter project. In the waste incineration power generation industry, the main factors hindering the improvement of steam parameters are high-temperature corrosion and wear problems on the flue gas side. At present, the industry mainly adopts measures such as surfacing welding and using better materials to extend the replacement cycle of corroded components in order to obtain a higher main steam temperature and power generation efficiency. Therefore, the development trend of the industry is that the parameters are getting higher and higher.

[0027] Theoretically, existing medium-temperature medium-pressure projects can increase economic benefits by means of technological transformation to improve the main steam parameters. This method is mainly achieved by replacing the waste heat boiler, steam turbine, main steam, main feed water system, etc. However, in the implementation process, problems such as high technological transformation costs of equipment and systems and long recovery periods of investment costs will be faced. The technological transformation requires shutdown for construction and has a long cycle, during which the economic losses are large, and the lack of a place to dispose of the waste also has a negative social impact on the enterprise. The above factors have led to the fact that although the application of medium-temperature sub-high-pressure parameters in the industry is quite mature at present, few early-established medium-temperature medium-pressure projects improve economic benefits by increasing parameters.

[0028] Therefore, for these existing medium-temperature medium-pressure waste incineration boiler systems, a technological transformation method is needed to optimize the thermal cycle to improve power generation efficiency and economic benefits without changing the main steam parameters.

[0029] This application proposes a medium-temperature and medium-pressure reheat system for waste incineration power generation. Based on the existing medium-temperature and medium-pressure thermal system, without increasing the main steam temperature and pressure, the steam reheater 300 uses the saturated steam of the waste heat boiler 100 to heat the exhaust steam of the high-pressure cylinder 210 of the steam turbine, so that it enters the low-pressure cylinder 220 of the steam turbine at a higher temperature to improve the power generation efficiency.

[0030] Refer to Figure 1 As shown in the figure, the medium-temperature and medium-pressure reheat system for waste incineration power generation in the embodiment of this application includes a waste heat boiler 100, a steam turbine 200, a steam reheater 300, and a condensate pump 400. Among them, the high-temperature steam generated by the waste heat boiler 100 is transported to the steam turbine 200 to do work. The steam turbine 200 includes a high-pressure cylinder 210 and a low-pressure cylinder 220 of the steam turbine. After the high-temperature steam enters the high-pressure cylinder 210 of the steam turbine to do work, both the temperature and pressure decrease. At this time, the steam after temperature and pressure reduction enters the steam reheater 300 to be reheated again to increase the temperature again, so that more heat energy can be converted into electric energy when it enters the low-pressure cylinder 220 of the steam turbine subsequently. The heat source of the steam reheater 300 is the saturated steam of the waste heat boiler 100. The condensed water after heat exchange in the steam reheater 300 is transported back to the waste heat boiler 100 by the condensate pump 400 for reheating and evaporation again, realizing the heat cycle between the waste heat boiler 100 and the steam reheater 300.

[0031] Specifically, the steam turbine 200 adopts a reheat structure, and can adopt a condensing or extraction condensing structure, and the rotational speed adopts a high rotational speed or a conventional rotational speed. The steam reheater 300 is a vertical or horizontal shell-and-tube heat exchanger, and uses the saturated steam extracted from the steam drum of the waste heat boiler 100 to exchange heat with the exhaust steam of the high-pressure cylinder 210 of the steam turbine. The two kinds of steam do not directly contact. The saturated steam extracted from the steam drum of the waste heat boiler 100 transfers heat to the exhaust steam of the high-pressure cylinder 210 of the steam turbine through the steam reheater 300 to complete the temperature rise of it.

[0032] The main steam port of the waste heat boiler 100 transports superheated steam to the main steam inlet of the high-pressure cylinder 210 of the steam turbine, and the saturated steam port of the steam drum of the waste heat boiler 100 transports saturated steam to the steam reheater 300. The exhaust steam of the high-pressure cylinder 210 of the steam turbine is connected to the steam reheater 300. The steam reheater 300 uses the saturated steam extracted from the waste heat boiler 100 to reheate the exhaust steam of the high-pressure cylinder 210 of the steam turbine again and transports it to the low-pressure cylinder 220 of the steam turbine. The condensate outlet of the steam reheater 300 is connected to the condensate pump 400, and the condensate pump 400 transports the condensed water discharged from the steam reheater 300 to the waste heat boiler 100 for reheating and evaporation again.

[0033] Furthermore, the medium-temperature, medium-pressure and reheat system for waste incineration power generation further includes a low-pressure heater 500. The low-pressure heater 500 is connected to the steam extraction port of the low-pressure cylinder 220 of the steam turbine. The steam extracted from the low-pressure cylinder 220 of the steam turbine exchanges heat with the condensate water in the low-pressure heater 500.

[0034] Furthermore, the medium-temperature, medium-pressure and reheat system for waste incineration power generation further includes a condenser 600 and a condensate pump 700. The steam inlet of the low-pressure heater 500 is connected to the steam extraction port of the low-pressure cylinder 220 of the steam turbine, and the exhaust port of the low-pressure cylinder 220 of the steam turbine is connected to the steam inlet of the condenser 600. Among them, the low-pressure cylinder 220 of the steam turbine delivers exhausted steam to the condenser 600, and the low-pressure heater 500 delivers the heat-exchanged hydrophobic water to the condenser 600. The condenser 600 condenses the steam, and the condensate pump 700 delivers the condensed water in the condenser 600 to the low-pressure heater 500 to heat the condensed water.

[0035] Furthermore, the medium-temperature, medium-pressure and reheat system for waste incineration power generation further includes a deaerator 800. The condensate water outlet of the low-pressure heater 500 is connected to the deaerator 800. The deaerator 800 is used to remove oxygen and other non-condensable gases in the boiler feed water, and the water outlet of the deaerator 800 supplies feed water to the waste heat boiler 100.

[0036] Furthermore, the medium-temperature, medium-pressure and reheat system for waste incineration power generation further includes a boiler feed pump 900. The boiler feed pump 900 is connected to the water outlet of the deaerator 800 and delivers the boiler feed water to the waste heat boiler 100 for the next heat cycle.

[0037] Furthermore, the exhaust port of the high-pressure cylinder 210 of the steam turbine is connected to the steam inlet of the deaerator 800 through a pipeline, so that the exhaust steam of the high-pressure cylinder 210 of the steam turbine can heat the boiler feed water discharged from the deaerator 800.

[0038] Specifically, the steam temperature delivered from the waste heat boiler 100 to the high-pressure cylinder 210 of the steam turbine is 380 to 470 °C, and the steam pressure is 3.43 to 5.3 MPa, which is within the parameter range of medium temperature and medium pressure. The steam discharged from the waste heat boiler 100 does not pass through other devices for temperature increase or pressure increase.

[0039] Specifically, the steam temperature delivered from the waste heat boiler 100 to the steam reheater 300 is 253 to 274 °C, and the steam pressure is 4.18 to 5.8 MPa.

[0040] Specifically, the steam temperature delivered from the high-pressure cylinder 210 of the steam turbine to the steam reheater 300 is 160 to 200 °C, and the steam pressure is 0.45 to 0.8 MPa.

[0041] Specifically, the steam temperature of the steam reheater 300 delivered to the low-pressure cylinder 220 of the steam turbine is 240 to 270 °C, and the steam pressure is 0.4 to 0.8 MPa.

[0042] Referring to the following table, taking a project with a domestic daily treatment scale of 750 t and a low calorific value of 7100 kJ / kg entering the furnace as an example, a traditional medium-temperature and medium-pressure waste incineration power generation system and the technical solution of the present invention are respectively selected, and the thermal calculations of the two are summarized as follows:

[0043] Medium temperature and medium pressure Technical solution of the present invention Incineration volume (t / d) 700 700 Main steam pressure (MPa.a) 4.0 4.0 Main steam temperature (°C) 400 400 Main steam flow rate (t / h) 71.49 68.27 Power generation (kW) 15399 16034 Overall plant thermal efficiency (%) 24.87 25.95

[0044] It can be seen that without changing the main steam pressure and main steam temperature, when using the medium-temperature, medium-pressure and reheat system for waste incineration power generation of the present invention, both the power generation amount and the overall plant thermal efficiency are significantly improved.

[0045] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention within the knowledge scope of those of ordinary skill in the art. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A medium-temperature and medium-pressure reheating system for waste incineration power generation, characterized in that: It includes a waste heat boiler, a steam turbine, a steam reheater and a drain pump, wherein the steam turbine includes a steam turbine high-pressure cylinder and a steam turbine low-pressure cylinder, wherein: The main steam port of the waste heat boiler delivers superheated steam to the main steam inlet of the high-pressure cylinder of the steam turbine, the saturated steam port of the waste heat boiler drum delivers saturated steam to the steam reheater, the exhaust port of the high-pressure cylinder of the steam turbine is connected to the steam reheater, the steam reheater uses the saturated steam extracted from the waste heat boiler drum to reheat the exhaust steam of the high-pressure cylinder of the steam turbine and outputs it to the low-pressure cylinder of the steam turbine, the condensate outlet of the steam reheater is connected to the drain pump, and the drain pump delivers the condensate discharged from the steam reheater to the waste heat boiler for re-heating and evaporation.

2. The medium-temperature and medium-pressure reheat system for waste incineration power generation according to claim 1 is characterized in that: The medium-temperature and medium-pressure reheating system for waste incineration power generation also includes a low-pressure heater, which is connected to the steam extraction port of the low-pressure cylinder of the steam turbine. The steam extraction of the low-pressure cylinder of the steam turbine and condensate are heat exchanged in the low-pressure heater.

3. The medium-temperature and medium-pressure reheat system for waste incineration power generation according to claim 2 is characterized in that: The medium-temperature and medium-pressure reheating system for waste incineration power generation also includes a condenser and a condensate pump. The drain port of the low-pressure heater is connected to the condenser. The condenser condenses the exhaust steam of the low-pressure cylinder of the turbine. The condensate pump transports the condensed water in the condenser to the low-pressure heater to heat the condensed water.

4. The medium-temperature and medium-pressure reheat system for waste incineration power generation according to claim 2 is characterized in that: The medium-temperature and medium-pressure reheat system for waste incineration power generation also includes a deaerator. The condensate outlet of the low-pressure heater is connected to the deaerator. The deaerator is used to remove oxygen and other non-condensable gases in the boiler feed water. The water outlet of the deaerator provides water to the waste heat boiler.

5. The medium-temperature and medium-pressure reheating system for waste incineration power generation according to claim 4 is characterized in that: The medium-temperature and medium-pressure reheating system for waste incineration power generation also includes a boiler feed water pump, which is connected to the water outlet of the deaerator and transports boiler feed water to the waste heat boiler for the next heat cycle.

6. The medium-temperature and medium-pressure reheat system for waste incineration power generation according to any one of claims 1 to 5, characterized in that: The steam temperature delivered by the waste heat boiler to the high-pressure cylinder of the steam turbine is 380 to 470° C., and the steam pressure is 3.43 to 5.3 MPa.

7. The medium-temperature and medium-pressure reheat system for waste incineration power generation according to any one of claims 1 to 5, characterized in that: The steam temperature delivered from the waste heat boiler to the steam reheater is 253 to 274° C., and the steam pressure is 4.18 to 5.8 MPa.

8. The medium-temperature and medium-pressure reheat system for waste incineration power generation according to any one of claims 1 to 5, characterized in that: The steam temperature delivered from the high-pressure cylinder of the steam turbine to the steam reheater is 160 to 200° C., and the steam pressure is 0.45 to 0.8 MPa.

9. The medium-temperature and medium-pressure reheat system for waste incineration power generation according to any one of claims 1 to 5, characterized in that: The steam temperature delivered by the steam reheater to the low-pressure cylinder of the steam turbine is 240 to 270° C., and the steam pressure is 0.4 to 0.8 MPa.

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