Heat supply and power generation system and control method thereof

Abstract

The invention provides a heat supply and power generation system and a control method thereof, and belongs to the technical field of heat supply and power generation. The system comprises a thermal generator set, the thermal generator set comprises a superheater, a high-pressure cylinder, a reheater, an intermediate-pressure cylinder, a low-pressure cylinder and a condenser which are sequentially arranged along a steam moving path, and the system further comprises an intermediate-pressure heat supply unit connected with a steam outlet of the reheater and used for supplying heat to heat consumers; the low-pressure heat supply unit is connected with a steam outlet of the medium-pressure cylinder and used for supplying heat to heat consumers; a steam inlet of the steam supplementing pipeline is connected with a steam outlet of the high-pressure cylinder, and a steam outlet of the steam supplementing pipeline is connected with a steam inlet of the middle section of the intermediate-pressure cylinder; a steam inlet of the exhaust pipeline is connected with a steam outlet of the high-pressure cylinder, and a steam outlet of the exhaust pipeline is connected with a steam inlet of the condenser. The system is simple in structure, the stability of heat supply under the wide load can be improved, and the system operation safety and economical efficiency are high.

Description

Technical Field

[0001] The present invention relates to the technical field of heating and power generation, and in particular to a heating and power generation system and a control method for the heating and power generation system. Background Art

[0002] With the rapid increase in installed capacity of new energy power generation, thermal power units are gradually transforming from the main power source to the deep peak-shaving power source. Cogeneration is an important means of efficient utilization of energy in thermal power units. It has significant advantages in energy conservation and emission reduction, and will become an important direction for the transformation and development of thermal power units in the future. The heating of cogeneration units is divided into residential heating and industrial heating. Heating and heating have relatively complete heating systems such as extraction steam heating, low-grade thermal energy graded heating and heat pump waste heat recovery heating. Industrial heating, especially according to the level of heating parameters, can be divided into high-pressure heating, medium-pressure heating and low-pressure heating. According to the steam supply method, it can be divided into temperature reduction and pressure reduction heating scheme, pressure matcher heating scheme, and back pressure machine heating scheme.

[0003] For the desuperheating and decompression heating scheme currently commonly used in industrial heating, the system is affected by the use of steam extraction from a steam extraction point with a higher pressure or temperature level, and then the steam is desuperheated and decompressed before being used by the users. The loss is too large and the heating economy is too low; for the heating scheme of extracting steam from hot or cold through the central regulating valve, the throttling parameter adjustment of the central regulating valve under large flow heating conditions often leads to a reduction of more than 10% in the efficiency of the intermediate pressure cylinder, and the overall heating economy is not high; for the scheme of exhausting steam from the intermediate pressure cylinder, as the operating load of the generator set decreases, the steam extraction capacity will drop sharply. Therefore, it will reduce the power generation efficiency and the stability of heating under a wide load; the safety and economy of the system operation cannot be guaranteed. Summary of the invention

[0004] The purpose of the embodiments of the present invention is to provide a heat supply and power generation system and a control method thereof, so as to solve the problem that the heat supply method in the above-mentioned prior art will reduce the power generation efficiency and the stability of heat supply under a wide load, and cannot ensure the safety and economy of system operation.

[0005] In order to achieve the above-mentioned object, an embodiment of the present invention provides a heat supply and power generation system, including a thermal power generation unit, the thermal power generation unit including a superheater, a high-pressure cylinder, a reheater, a medium-pressure cylinder, a low-pressure cylinder and a condenser arranged in sequence along a steam movement path, and the system also includes:

[0006] A medium-pressure heating unit, connected to the steam outlet of the reheater, for supplying heat to heat users;

[0007] A low-pressure heating unit, connected to the steam outlet of the medium-pressure cylinder, for supplying heat to heat users;

[0008] An air supply pipeline, wherein the steam inlet of the air supply pipeline is connected to the steam outlet of the high-pressure cylinder, and the steam outlet of the air supply pipeline is connected to the steam inlet of the middle section of the intermediate-pressure cylinder, for supplying steam to the intermediate-pressure cylinder;

[0009] An exhaust pipeline, a steam inlet of the exhaust pipeline is connected to a steam outlet of the high-pressure cylinder, and a steam outlet of the exhaust pipeline is connected to a steam inlet of the condenser.

[0010] Optionally, the medium pressure heating unit comprises:

[0011] A medium-pressure steam supply pipeline, wherein the steam inlet of the medium-pressure steam supply pipeline is connected to the steam outlet of the reheater, and the medium-pressure steam supply pipeline is provided with an electric valve, a check valve and a flow regulating valve;

[0012] A medium-pressure heating manifold, wherein the inlet end of the medium-pressure heating manifold is connected to the steam outlet of the medium-pressure steam supply pipeline, and the outlet end of the medium-pressure heating manifold is connected to a heat user.

[0013] Optionally, the low-pressure heating unit comprises:

[0014] A low-pressure steam supply pipeline, the steam inlet of the low-pressure steam supply pipeline is connected to the steam outlet of the medium-pressure cylinder, and the low-pressure steam supply pipeline is provided with an electric valve, a check valve and a flow regulating valve;

[0015] A low-pressure heat supply heat exchanger, wherein the inlet end of the low-pressure heat supply heat exchanger is connected to the steam outlet of the low-pressure steam supply pipeline, and the outlet end of the low-pressure heat supply heat exchanger is connected to a heat user.

[0016] Optionally, the system further includes:

[0017] A low-pressure heating auxiliary pipeline, the steam inlet of the low-pressure heating auxiliary pipeline is connected to the steam outlet of the high-pressure cylinder, the steam outlet of the low-pressure heating auxiliary pipeline is connected to the inlet end of the low-pressure heating heat exchanger, and an electric valve, a check valve and a flow regulating valve are arranged on the low-pressure heating auxiliary pipeline.

[0018] Optionally, the steam inlets of the air supply pipeline and the exhaust pipeline are connected to the steam outlet of the high-pressure cylinder through a high-exhaust ventilation valve.

[0019] Optionally, the air supply pipeline is provided with an electric valve, a check valve and a flow regulating valve;

[0020] An electric valve is provided on the exhaust pipe;

[0021] A check valve is provided between the high-pressure cylinder and the reheater;

[0022] A flow regulating valve is provided between the intermediate pressure cylinder and the reheater, and between the intermediate pressure cylinder and the low pressure cylinder.

[0023] A second aspect of the present invention provides a control method for a heat supply and power generation system, which is applied to the above-mentioned heat supply and power generation system, and the method comprises:

[0024] Obtain the operating load of the thermal power generating unit;

[0025] If the operating load is less than or equal to a set threshold, the air supply pipeline is controlled to be open;

[0026] If the operating load is greater than a set threshold, the air supply pipeline is controlled to be closed.

[0027] Optionally, the method further includes:

[0028] After confirming that the thermal power generator set has entered the start-up and shutdown conditions, the exhaust pipeline is opened and the air supply pipeline is closed.

[0029] A third aspect of the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned control method for the heating and power generation system when executing the computer program.

[0030] A fourth aspect of the present invention provides a readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute the above-mentioned control method for a heat supply and power generation system.

[0031] The technical solution has a simple structure and can supply steam to the medium-pressure cylinder through the air supply pipeline, thereby increasing the steam pressure of the medium-pressure and low-pressure heating extraction steam, reducing the dependence of the medium and low-pressure heating under low load on the throttling parameter adjustment of the intermediate control valve, and improving the efficiency of the medium-pressure cylinder and the stability of heating under a wide load; in addition, the steam is transported to the condenser through the exhaust pipeline to protect the high-pressure cylinder, thereby effectively improving the safety and economy of the system operation.

[0032] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0034] Figure 1 It is a structural block diagram of the heat supply and power generation system provided by the present invention;

[0035] Figure 2 It is a structural schematic diagram of the heat supply and power generation system provided by the present invention;

[0036] Figure 3It is a flow chart of the control method of the heating and power generation system provided by the present invention.

[0037] Description of Reference Numerals

[0038] 2-Medium-pressure heating unit; 3-Heat user; 4-Low-pressure heating unit;

[0039] 5-air supply pipeline; 6-exhaust pipeline; 7-low-pressure heating auxiliary pipeline;

[0040] 11-superheater; 12-high pressure cylinder; 13-reheater;

[0041] 14-intermediate pressure cylinder; 15-low pressure cylinder; 16-condenser;

[0042] 21-medium pressure steam supply pipeline; 22-medium pressure heating header; 41-low pressure steam supply pipeline;

[0043] 42- low-pressure heating heat exchanger; 101- electric valve; 102- check valve;

[0044] 103-flow regulating valve; 104-high exhaust ventilation valve. DETAILED DESCRIPTION

[0045] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the embodiment of the present invention, and is not used to limit the embodiment of the present invention.

[0046] In the embodiments of the present invention, unless otherwise specified, directional words such as "up, down, left, right" generally refer to the directions or positional relationships shown in the accompanying drawings, or the directions or positional relationships in which the inventive product is usually placed when in use.

[0047] The terms “first”, “second”, “third”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0048] The terms "parallel", "vertical", etc. do not mean that the components must be absolutely parallel or vertical, but can be slightly tilted. For example, "parallel" only means that its direction is more parallel than "vertical", and does not mean that the structure must be completely parallel, but can be slightly tilted.

[0049] The terms "horizontal", "vertical", "overhanging" and the like do not mean that the components are required to be absolutely horizontal, vertical or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0050] In addition, the terms "roughly" and "basically" are intended to explain that the relevant content does not require absolute precision, but can have certain deviations. For example, "roughly equal" does not only mean absolute equality. Since it is difficult to achieve absolute "equality" in actual production and operation, there are generally certain deviations. Therefore, in addition to absolute equality, "roughly equal" also includes the above-mentioned situation with certain deviations. Taking this as an example, in other cases, unless otherwise specified, the terms "roughly" and "basically" have similar meanings to the above.

[0051] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] Figure 1 It is a structural block diagram of the heat supply and power generation system provided by the present invention; Figure 2 It is a structural schematic diagram of the heat supply and power generation system provided by the present invention; Figure 3 It is a flow chart of the control method of the heating and power generation system provided by the present invention.

[0053] like Figure 1-2 As shown, this embodiment provides a heat supply and power generation system. First, the system includes a thermal power generation unit, which includes a superheater 11, a high-pressure cylinder 12, a reheater 13, a medium-pressure cylinder 14, a low-pressure cylinder 15, and a condenser 16, which are sequentially arranged along the steam movement path. The structure of the thermal power generation unit is the prior art known to those skilled in the art, so it will not be repeated here. Based on the structure of the existing thermal power generation unit, the heat supply and power generation system in this scheme also includes:

[0054] A medium-pressure heating unit 2, connected to the steam outlet of the reheater 13, for supplying heat to a heat user 3;

[0055] A low-pressure heating unit 4 is connected to the steam outlet of the medium-pressure cylinder 14 and is used to supply heat to the heat user 3;

[0056] An air supply pipeline 5, wherein the steam inlet of the air supply pipeline 5 is connected to the steam outlet of the high-pressure cylinder 12, and the steam outlet of the air supply pipeline 5 is connected to the steam inlet of the middle section of the intermediate-pressure cylinder 14, for supplying steam to the intermediate-pressure cylinder 14;

[0057] The exhaust pipeline 6 , the steam inlet of the exhaust pipeline 6 is connected to the steam outlet of the high-pressure cylinder 12 , and the steam outlet of the exhaust pipeline 6 is connected to the steam inlet of the condenser 16 .

[0058] Specifically, in this embodiment, steam of different qualities is supplied by the medium-pressure heating unit 2 and the low-pressure heating unit 4, respectively, to achieve differentiated steam supply and improve the scope of application. The supplementary steam port provided on the middle section of the medium-pressure cylinder 14 is located behind the medium-pressure fifth-stage blade of the medium-pressure cylinder 14 (the middle part of the medium-pressure cylinder 14), and the steam outlet of the supplementary air pipeline 5 is connected to the supplementary steam port behind the medium-pressure fifth-stage blade of the medium-pressure cylinder 14. The steam pressure in the medium-pressure cylinder 14 is lower than the high-pressure exhaust steam pressure, and the steam temperature after the medium-pressure fifth-stage blade is close to the high-pressure exhaust steam temperature, thereby improving the power generation efficiency of the medium-pressure cylinder 14.

[0059] Furthermore, the medium-pressure heating unit 2 comprises:

[0060] A medium-pressure steam supply pipeline 21, the steam inlet of the medium-pressure steam supply pipeline 21 is connected to the steam outlet of the reheater 13, and the medium-pressure steam supply pipeline 21 is provided with an electric valve 101, a check valve 102 and a flow regulating valve 103;

[0061] A medium-pressure heating manifold 22 , wherein the inlet end of the medium-pressure heating manifold 22 is connected to the steam outlet of the medium-pressure steam supply pipeline 21 , and the outlet end of the medium-pressure heating manifold 22 is connected to the heat user 3 .

[0062] Specifically, the electric valve 101 can be used to control the on-off of the pipeline; the check valve 102 can ensure the one-way flow of steam, thereby improving safety; and the flow control valve 103 can adjust the flow of steam from the medium-pressure steam supply pipeline 21 into the medium-pressure heating header 22. The steam is transferred through the medium-pressure heating header 22, thereby ensuring the stability of the steam flow, pressure and temperature.

[0063] Furthermore, the low-pressure heating unit 4 comprises:

[0064] A low-pressure steam supply pipeline 41, the steam inlet of the low-pressure steam supply pipeline 41 is connected to the steam outlet of the medium-pressure cylinder 14, and the low-pressure steam supply pipeline 41 is provided with an electric valve 101, a check valve 102 and a flow regulating valve 103;

[0065] A low-pressure heat supply heat exchanger 42 , wherein the inlet end of the low-pressure heat supply heat exchanger 42 is connected to the steam outlet of the low-pressure steam supply pipeline 41 , and the outlet end of the low-pressure heat supply heat exchanger 42 is connected to the heat user 3 .

[0066] Specifically, the electric valve 101 can be used to control the on-off of the pipeline; the check valve 102 can ensure the one-way flow of steam and improve safety; the flow control valve 103 can adjust the flow of steam entering the low-pressure heat exchanger 42 from the low-pressure steam supply pipeline 41. The low-pressure heat exchanger 42 is mainly used to heat the return water of the heating network for heating residents. Its heat source steam comes from the exhaust steam of the medium-pressure cylinder 14 and the exhaust steam of the high-pressure cylinder 12. In order to ensure the stability of heating and heat supply, the exhaust steam of the medium-pressure cylinder 14 is mainly used to heat the low-pressure heat exchanger 42 when the load is high. However, under low-load conditions, due to the insufficient exhaust flow of the medium-pressure cylinder 14, the low-pressure heat exchanger 42 can only be heated by the exhaust steam of the high-pressure cylinder 12 after de-temperature and pressure reduction. This leads to the waste of the available potential energy of high-quality steam. Therefore, the medium-pressure cylinder 14 is supplemented with air through the air supply pipeline 5 to ensure the exhaust flow of the medium-pressure cylinder 14.

[0067] Specifically, in this embodiment, an electric valve 101, a check valve 102 and a flow regulating valve 103 are provided on the air supply pipeline 5, so as to realize the on-off control of the air supply pipeline 5 and the regulation of the steam flow;

[0068] An electric valve 101 is provided on the exhaust pipe 6 to realize on-off control of the exhaust pipe 6;

[0069] A check valve 102 is provided between the high pressure cylinder 12 and the reheater 13 so that the steam can only flow in one direction;

[0070] Flow regulating valves 103 are provided between the intermediate pressure cylinder 14 and the reheater 13 and between the intermediate pressure cylinder 14 and the low pressure cylinder 15 to adjust the steam flow entering the intermediate pressure cylinder 14 to ensure that the steam inlet pressure of the intermediate pressure cylinder remains unchanged; and to adjust the steam flow entering the low pressure cylinder 15.

[0071] In another embodiment, the steam inlets of the air supply pipeline 5 and the exhaust pipeline 6 are connected to the steam outlet of the high-pressure cylinder 12 through the high-discharge ventilation valve 104. The high-discharge ventilation valve 104 can be provided in two, each of which corresponds to the air supply pipeline 5 and the exhaust pipeline 6; the high-discharge ventilation valve 104 can also be provided in one, and the steam outlet of the high-discharge ventilation valve 104 is split to connect the air supply pipeline 5 and the exhaust pipeline 6 respectively.

[0072] In another embodiment, the system further includes: a low-pressure heating auxiliary pipeline 7, the steam inlet of the low-pressure heating auxiliary pipeline 7 is connected to the steam outlet of the high-pressure cylinder 12, and the steam outlet of the low-pressure heating auxiliary pipeline 7 is connected to the inlet end of the low-pressure heating heat exchanger 42. In this way, the low-pressure heating auxiliary pipeline 7 is set as a redundant design, so that the steam at the steam outlet of the high-pressure cylinder 12 can directly supply steam to the low-pressure heating heat exchanger 42; in order to realize the pipeline opening and closing control of the low-pressure heating auxiliary pipeline 7 and realize the control of the steam flow, an electric valve 101, a check valve 102 and a flow control valve 103 are arranged on the low-pressure heating auxiliary pipeline 7. The flow control valve 103 has the function of reducing temperature and pressure, and can realize the regulation of steam temperature and pressure.

[0073] More specifically, by adjusting the flow regulating valve 103 arranged on the air supply pipeline 5 and the flow regulating valve 103 arranged between the intermediate pressure cylinder 14 and the reheater 13, the axial thrust of the high pressure cylinder and the intermediate pressure cylinder can be self-balanced to ensure the operating stability and power generation efficiency of the unit.

[0074] In addition, by adjusting the flow regulating valve 103 provided between the medium-pressure cylinder 14 and the low-pressure cylinder 15 and the flow regulating valve 103 provided on the low-pressure steam supply pipeline 41, the steam flow entering the low-pressure cylinder 15 and being transported to the low-pressure heat supply heat exchanger 42 can be controlled.

[0075] More specifically, in this embodiment, one end of the air supply pipeline 5 is connected to the steam extraction port of the high-pressure cylinder exhaust pipe, and the connection point is located before the check valve (N1), and the other end is connected to the steam supply port of the medium-pressure cylinder 14, on which a high-pressure exhaust ventilation valve (D1), a check valve (N4), a flow regulating valve (V4) and an electric valve (D2) are arranged in sequence; one end of the exhaust pipeline 6 is connected to the air supply pipeline 5, and the connection point is located after the high-pressure exhaust ventilation valve (D1), and the other end is connected to the condenser 16, on which an electric valve (D3) is arranged; the steam outlet of the reheater 13 is connected to the medium-pressure steam supply pipeline 21 and the medium-pressure cylinder steam inlet pipeline through a pipeline, and a flow regulating valve T2 is arranged on the medium-pressure cylinder steam inlet pipeline, and electric valves (D2) are arranged in sequence on the medium-pressure steam supply pipeline 21 A motor valve (D5), a check valve (N3), and a flow regulating valve (V3); one end of the low-pressure cylinder steam inlet pipeline is connected to the exhaust port of the medium-pressure cylinder, and the other end is connected to the low-pressure cylinder steam inlet, on which a flow regulating valve (V1) is provided; the exhaust port of the medium-pressure cylinder is connected to the low-pressure steam supply pipeline 41, and the connection point is located before the flow regulating valve (V1), on which an electric valve (D4), a check valve (N2), and a flow regulating valve (V2) are provided in sequence; the exhaust port of the high-pressure cylinder is connected to the steam side inlet of the low-pressure heat supply heat exchanger 42 through the low-pressure steam supply pipeline 41, and the connection point of the low-pressure steam supply pipeline 41 is located after the high-pressure exhaust motor check valve (N1), on which an electric valve (D6), a check valve (N5) and a flow regulating valve (V5) are provided in sequence.

[0076] Among them, the flow control valve (T2) has the ability to adjust. After the medium-pressure heating extraction steam is adjusted by the flow control valve (T2), the medium-pressure cylinder steam inlet pressure can be kept constant; the medium-pressure cylinder steam supply port is located after the medium-pressure 5th stage blade, the steam pressure after the medium-pressure 5th stage blade (0.6MPa) is lower than the high-pressure exhaust steam pressure (2.2MPa), and the steam temperature after the medium-pressure 5th stage blade is 330℃, which is close to the high-pressure exhaust steam temperature of 324℃; the high-pressure exhaust ventilation valve (D1), the air supply pipeline 5 and the high-pressure exhaust ventilation valve (D1) to the exhaust pipeline 6, and the high-pressure cylinder exhaust steam to The electric valve (D6), check valve (N5) and flow control valve (V5) of low-pressure heating are original equipment, and the air supply pipeline 5, electric valve (D2) and electric valve (D3), check valve (N4) and flow control valve (V4) are new equipment; the flow control valve (V5) and flow control valve (V3) have the functions of cooling and reducing pressure; the flow control valve (V4) is used to control the steam supply flow of the medium-pressure cylinder; it is jointly adjusted by the flow control valve (V4) and the flow control valve (T2) to ensure the self-balancing of the axial thrust of the high- and medium-pressure cylinders.

[0077] The low-pressure heating heat exchanger 42 is mainly used to heat the return water of the heating network for heating residents. Its heat source steam comes from the exhaust steam of the medium-pressure cylinder and the exhaust steam of the high-pressure cylinder. In order to ensure the stability of heating and heat supply, the medium-pressure cylinder exhaust steam is mainly used to heat the heating heat exchanger when the load is high. Under low-load conditions, due to insufficient exhaust steam flow of the medium-pressure cylinder, the heating heat exchanger can only be heated by the high-pressure cylinder exhaust steam after cooling and reducing the pressure. This results in a waste of the usable potential energy of high-quality steam.

[0078] Control of medium-pressure heating parameters: The medium-pressure heating steam source is hot reheating. When heating, the electric valve (D5), check valve (N3), and flow control valve (V3) are opened. The flow control valve (V3) and the flow control valve (T2) control the pressure of the medium-pressure heating system to 1.1 MPa and the extraction steam flow rate. As the load decreases, when the hot reheat extraction steam pressure does not meet the heating pressure, the high-exhaust ventilation valve is used to supplement steam to the medium-pressure cylinder. At this time, the high-exhaust ventilation valve (D1), check valve (N4), flow control valve (V4), and electric valve (D2) are opened. The flow control valve (V4) and the flow control valve (V3) are used to simultaneously control the pressure of the medium-pressure heating system to 1.1 MPa and the extraction steam flow rate. At this time, it is possible to avoid or reduce the reliance on the medium control valve to hold air to increase the steam inlet pressure of the medium-pressure cylinder, thereby improving the efficiency of the medium-pressure cylinder.

[0079] Low-pressure heating parameter control: The steam source for low-pressure heating is cold re-extraction steam and middle exhaust steam extraction. According to the principle of energy level matching, middle exhaust steam extraction is preferred for low-pressure heating. The electric valve (D4), check valve (N2), and flow control valve (V2) are opened. The flow control valve (V2) and flow control valve (V1) are used to control the pressure and flow of the medium-pressure heating system to 0.15MPa; as the load decreases, when the middle exhaust steam pressure does not meet the heating pressure, the high-exhaust ventilation valve is used to supplement steam to the middle-pressure cylinder. At this time, the high-exhaust ventilation valve (D1), check valve (N4), flow control valve (V4), and electric valve (D2) are opened. The flow control valve (V4) and flow control valve (V2) are used to simultaneously control the heating pressure to 0.15MPa and the steam extraction flow. This can avoid the need to use high-quality steam to reduce the temperature and pressure of the low-pressure heating heat exchanger through the high-pressure cylinder exhaust steam under low-load conditions.

[0080] Analysis of high-pressure exhaust ventilation valve operation: The original high-pressure exhaust ventilation valve can be modified to save investment and space, and can also realize disturbance-free switching operation between low-load heating and start-up and shutdown conditions. When the low-load heating condition is in operation, the medium-pressure cylinder is supplemented with steam through the high-pressure exhaust ventilation valve to ensure the medium and low-pressure heating steam pressure and flow, and improve the unit economy; when the unit is in operation under start-up and shutdown conditions, the high-pressure cylinder inlet and exhaust steam flow is small, and the check valve (N1) may be in a closed or very small opening state. If the steam flow in the high-pressure cylinder is not smooth, the temperature will become higher and higher due to the friction of the high-pressure cylinder blades, and finally exceed the safe temperature of the high-pressure cylinder blade material, causing blade damage; by opening the high-pressure exhaust ventilation valve (D1) and the electric valve (D3), because the condenser is under negative pressure, this can accelerate the flow of steam in the high-pressure cylinder, and take away the heat generated by the friction of the high-pressure cylinder blades in time to avoid safety accidents.

[0081] Specifically, the flow control valve adopts a hydraulic control valve.

[0082] like Figure 3 As shown, this embodiment also provides a control method for a heat supply and power generation system, which is applied to the above-mentioned heat supply and power generation system, and the method includes:

[0083] Obtain the operating load of the thermal power generating unit;

[0084] If the operating load is less than or equal to a set threshold, the air supply pipeline is controlled to be open;

[0085] If the operating load is greater than a set threshold, the air supply pipeline is controlled to be closed.

[0086] Specifically, in this embodiment, by collecting the operating load of the thermal power generating set, the opening and closing of the air supply pipeline and the air supply pipeline are controlled accordingly, which can increase the steam pressure of the medium-pressure and low-pressure heating extraction steam, reduce the dependence of the medium and low-pressure heating under low load on the throttling parameters of the medium regulating valve, and improve the efficiency of the medium-pressure cylinder and the stability of heating under a wide load.

[0087] Specifically, when the thermal power unit is operating at low load, steam is supplied to the intermediate pressure cylinder through the air supply pipeline. The steam supply pressure is higher than the flow steam pressure at the steam supply port. According to the principles of fluid mechanics, the steam pressure at the steam inlet and exhaust ports of the intermediate pressure cylinder can be increased, thereby increasing the steam pressure at the intermediate pressure and low pressure heating steam extraction ports. The traditional low load heating condition requires the intermediate control valve to hold air to increase the intermediate pressure cylinder inlet and exhaust steam pressures. This solution can reduce the dependence on the throttling parameters of the intermediate control valve while ensuring the heating pressure under low load, thereby improving the efficiency of the intermediate pressure cylinder.

[0088] When the original heating system is under low load conditions, the exhaust steam from the intermediate pressure cylinder is insufficient to supply low pressure steam, and the exhaust steam from the high pressure cylinder needs to be cooled and decompressed before supplying low pressure steam, which wastes high quality steam. This solution can increase the steam flow of the turbine stage after the steam supply port by supplying steam to the intermediate pressure cylinder through the air supply pipeline. This part of the steam supply flow first works in the intermediate pressure cylinder and then is introduced into the intermediate pressure cylinder exhaust steam to the low pressure heat exchanger for heating, which not only improves the work capacity of the intermediate pressure cylinder but also ensures the low load and low pressure heating load, thus realizing the safe and efficient operation of the heating unit.

[0089] Furthermore, the method further comprises:

[0090] After confirming that the thermal power generator set has entered the start-up and shutdown conditions, the exhaust pipeline is opened and the air supply pipeline is closed.

[0091] Specifically, in this embodiment, when the thermal power generating unit enters the start-up and shutdown process, the inlet and exhaust steam flow rates of the high-pressure cylinder are small, and the check valve arranged between the high-pressure cylinder and the reheater may be in a non-open or very small opening state. If the steam flow in the high-pressure cylinder is not smooth, the temperature will become higher and higher due to the friction of the high-pressure cylinder blades, and finally exceed the safe temperature of the high-pressure cylinder blade material, causing damage to the blades. The condenser is under negative pressure, so the exhaust line is opened and the air supply line is closed, and the steam is transported to the condenser through the exhaust line, thereby accelerating the flow of steam in the high-pressure cylinder to take away the blast heat generated by the low-flow operation of the high-pressure cylinder, ensure the safety of the flow-through components of the high-pressure cylinder, protect the high-pressure cylinder, effectively improve the safety and economy of system operation, and reduce the occurrence of safety accidents.

[0092] This embodiment also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the control method of the heating and power generation system when executing the computer program.

[0093] This embodiment also provides a readable storage medium, on which instructions are stored, and the instructions are used to enable a machine to execute the above-mentioned control method of the heating and power generation system.

[0094] Example

[0095] Taking the power plant unit model CC210 / 125-12.75 / 1.8 / 0.325 as an example, the original design of the heating unit has an electrical load of more than 50% of the rated electrical load. 1.1MPa, 530℃, 50t / h steam is extracted from the hot re-pipeline, and then the medium-pressure steam of 1.1MPa, 320℃, 50t / h is supplied to the outside after pressure reduction and temperature reduction; 0.15MPa, 230℃, 50t / h steam is extracted from the middle exhaust pipe to supply the steam side of the low-pressure heat exchanger Steam; When the unit is under 157MW electrical load (75% of rated electrical load), the turbine medium-pressure regulating valve starts to be closed to meet the pressure requirement and supply 1.1MPa, 320℃, 55t / h of medium-pressure steam to the outside after cooling. When the unit is running at 105MW-157MW electrical load (50%-75% of rated electrical load), cold re-extraction steam needs to be used to cool and reduce the pressure to supply the low-pressure heat exchanger to meet the supply of 0.15MPa, 230℃, 50t / h of low-pressure steam to the outside.

[0096] Due to the use of the heating method with throttling parameters of the central regulating valve, the efficiency of the intermediate pressure cylinder drops sharply as the opening of the central regulating valve decreases, especially under low-load steam extraction conditions, the efficiency of the intermediate pressure cylinder is already lower than 70%, seriously affecting the economy of the unit. As the load of the unit decreases, the efficiency of the intermediate pressure cylinder caused by the throttling of the central regulating valve decreases, resulting in a decrease in the improvement in the economy of the unit brought about by industrial steam extraction, or even negative growth. At the same time, the original design heating condition requires the unit to operate at more than 50% of the rated electrical load, which no longer meets the current grid's requirement for deep peak regulation of at least 30%. Based on the air supply valve technology, a heating and power generation scheme suitable for wide load conditions is proposed in this scheme, providing 50t / h of medium-pressure heating steam (1.1MPa, 320℃) and 50t / h of medium-pressure heating steam (0.15MPa, 230℃) under all heating conditions.

[0097] In this scheme, when operating in the range of 30%-95% of the rated electrical load (63MW-200MW), it can meet the requirements of medium-pressure heating of 1.1MPa, 320℃, 50t / h and low-pressure heating of 0.15MPa, 230℃, 50t / h. The peak-shaving range is greatly widened compared with the original heating system (the electrical load under heating conditions is not less than 50% of the rated electrical load), and the heating system can be operated at 50% of the rated electrical load without the need for Zhonglian gate adjustment and cold regeneration to directly supply low-pressure heating, which improves the flexibility and economy of the heating system.

[0098] like Figure 1-2As shown, under rated heating conditions, the operating mode adopted in the range of 75% rated electric load to 95% rated electric load is: hot re-extraction steam is used as the medium-pressure heating steam source, and the middle exhaust extraction steam is used as the low-pressure heating steam source; the operating mode adopted in the range of 50% rated electric load to 75% rated electric load is: hot re-extraction steam is used as the medium-pressure heating steam source, and the middle exhaust extraction steam is used as the low-pressure heating steam source, and steam is supplemented to the medium-pressure cylinder through the air supplement pipeline; the operating mode adopted in the range of 30% rated electric load to 50% rated electric load is: hot re-extraction steam is used as the medium-pressure heating steam source, and the middle exhaust extraction steam is used as the low-pressure heating steam source, and steam is supplemented to the medium-pressure cylinder through the central joint valve parameter adjustment and air supplement pipeline.

[0099] Based on the test condition data of the original heating system, the comparative analysis of the economic performance of the heating power generation system of the present invention and the original heating system is shown in Table 1 below (medium pressure heating 1.1 MPa, 320°C, 50 t / h, low pressure heating 0.15 MPa, 230°C, 50 t / h):

[0100] Table 1 Comparative analysis of operating economics

[0101]

[0102]

[0103] It can be seen from the above table that: under the same heating conditions, the weighted power generation coal consumption of this scheme is reduced by an average of 0.94g / kWh compared with the original heating system (only considering the operation range of 50% to 75% of the rated electrical load), and the energy-saving effect is obvious; at the same time, due to the added air supply pipeline and exhaust pipeline, the disturbance-free switching of heating and start-stop operation can be achieved, and the system operation safety is high.

[0104] The optional implementation modes of the embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above implementation modes. Within the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical scheme of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention.

[0105] Those skilled in the art can understand that all or part of the steps in the above-mentioned embodiments can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions for making a single-chip microcomputer, a chip or a processor (processor) perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0106] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, the technical scheme of the embodiments of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner when there is no contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

[0107] In addition, various implementation modes of the embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed by the embodiments of the present invention.

Claims

1. A heat supply and power generation system, comprising a thermal power generating set, wherein the thermal power generating set comprises a superheater (11), a high pressure cylinder (12), a reheater (13), an intermediate pressure cylinder (14), a low pressure cylinder (15) and a condenser (16) arranged in sequence along a steam movement path, characterized in that: The system further comprises: A medium-pressure heating unit (2) connected to the steam outlet of the reheater (13) and used for supplying heat to a heat user (3); A low-pressure heating unit (4) connected to the steam outlet of the medium-pressure cylinder (14) and used for supplying heat to a heat user (3); An air supply pipeline (5), wherein the steam inlet of the air supply pipeline (5) is connected to the steam outlet of the high-pressure cylinder (12), and the steam outlet of the air supply pipeline (5) is connected to the steam inlet of the middle section of the medium-pressure cylinder (14), for supplying steam to the medium-pressure cylinder (14); An exhaust pipeline (6), the steam inlet of the exhaust pipeline (6) is connected to the steam outlet of the high-pressure cylinder (12), and the steam outlet of the exhaust pipeline (6) is connected to the steam inlet of the condenser (16).

2. The heating and power generation system according to claim 1, characterized in that: The medium-pressure heating unit (2) comprises: a medium-pressure steam supply pipeline (21), wherein a steam inlet of the medium-pressure steam supply pipeline (21) is connected to a steam outlet of the reheater (13), and an electric valve (101), a check valve (102) and a flow regulating valve (103) are provided on the medium-pressure steam supply pipeline (21); A medium-pressure heating manifold (22), wherein the inlet end of the medium-pressure heating manifold (22) is connected to the steam outlet of the medium-pressure steam supply pipeline (21), and the outlet end of the medium-pressure heating manifold (22) is connected to the heat user (3).

3. The heating and power generation system according to claim 1, characterized in that: The low-pressure heating unit (4) comprises: a low-pressure steam supply pipeline (41), wherein a steam inlet of the low-pressure steam supply pipeline (41) is connected to a steam outlet of the medium-pressure cylinder (14), and an electric valve (101), a check valve (102) and a flow regulating valve (103) are provided on the low-pressure steam supply pipeline (41); A low-pressure heat supply heat exchanger (42), wherein the inlet end of the low-pressure heat supply heat exchanger (42) is connected to the steam outlet of the low-pressure steam supply pipeline (41), and the outlet end of the low-pressure heat supply heat exchanger (42) is connected to the heat user (3).

4. The heating and power generation system according to claim 3, characterized in that: The system further comprises: A low-pressure heating auxiliary pipeline (7), wherein the steam inlet of the low-pressure heating auxiliary pipeline (7) is connected to the steam outlet of the high-pressure cylinder (12), the steam outlet of the low-pressure heating auxiliary pipeline (7) is connected to the inlet end of the low-pressure heating heat exchanger (42), and the low-pressure heating auxiliary pipeline (7) is provided with an electric valve (101), a check valve (102) and a flow regulating valve (103).

5. The heating and power generation system according to claim 1, characterized in that: The steam inlets of the air supply pipeline (5) and the exhaust pipeline (6) are both connected to the steam outlet of the high-pressure cylinder (12) via a high-discharge ventilation valve (104).

6. The heating and power generation system according to claim 5, characterized in that: The air supply pipeline (5) is provided with a check valve (102) and a flow regulating valve (103); The exhaust pipeline (6) is provided with an electric valve (101); A check valve (102) is provided between the high-pressure cylinder (12) and the reheater (13); A flow regulating valve (103) is provided between the intermediate pressure cylinder (14) and the reheater (13), and between the intermediate pressure cylinder (14) and the low pressure cylinder (15).

7. A control method for a heating and power generation system, applied to the heating and power generation system according to any one of claims 1 to 6, characterized in that: The method comprises: Obtain the operating load of the thermal power generating unit; If the operating load is less than or equal to a set threshold, the air supply pipeline is controlled to be open; If the operating load is greater than a set threshold, the air supply pipeline is controlled to be closed.

8. The control method of the heating and power generation system according to claim 7, characterized in that: The method further comprises: After confirming that the thermal power generator set has entered the start-up and shutdown conditions, the exhaust pipeline is opened and the air supply pipeline is closed.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the control method of the heating and power generation system according to any one of claims 7 to 8 is implemented.

10. A readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute the control method for a heat supply and power generation system according to any one of claims 7 to 8.

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