An air turbine system and its operation method

Abstract

The present invention provides an air turbine system and an operation method, including a compressed air source, which is communicated with the inlet of a high-pressure air turbine through a high-pressure inlet pipe; a high-pressure supplementary air pipe communicated with the supplementary air inlet of the high-pressure air turbine and a medium-pressure supplementary air pipe communicated with the inlet of a medium-pressure air turbine are connected in parallel on the high-pressure inlet pipe; a high-pressure supplementary air valve is arranged on the high-pressure supplementary air pipe, and a medium-pressure supplementary air valve is arranged on the medium-pressure supplementary air pipe; a high-pressure on-off valve and a high-pressure regulating valve are arranged on the high-pressure inlet pipe; a medium-pressure inlet pipe communicated with the inlet of the medium-pressure air turbine and a low-pressure inlet pipe communicated with the inlet of a low-pressure air turbine are connected in parallel at the exhaust port of the high-pressure air turbine; a medium-pressure on-off valve and a medium-pressure regulating valve are arranged on the medium-pressure inlet pipe; a first low-pressure on-off valve, a low-pressure regulating valve and a second low-pressure on-off valve are arranged on the low-pressure inlet pipe; the exhaust port of the medium-pressure air turbine is communicated with the low-pressure inlet pipe through a medium-pressure exhaust pipe; the present invention controls the connection relationship of each air turbine to ensure that the total output power remains unchanged.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressed air energy storage, and in particular relates to an air turbine system capable of adapting to a wide range of changes in the pressure of an air compression source and an operating method thereof. Background Art

[0002] The compressed air energy storage system is a new type of energy storage technology with the advantages of a wide power range, long life, unlimited storage time, and environmental friendliness. It has become an important research direction of energy storage technology. Its principle is to use excess electricity to compress the air and store it in confined spaces such as salt caverns and high-pressure gas tanks during low-peak electricity consumption. During peak electricity consumption, the stored high-pressure air is used to drive the air turbine to generate electricity to meet electricity demand. Since the amount of compressed air that can be stored in confined spaces such as salt caverns and high-pressure gas tanks is limited, during the work of the air turbine, as the compressed air flows out, the storage pressure will continue to decrease, causing the output power of the air turbine to continue to decrease and unable to meet the output requirements; therefore, for a compressed air energy storage system with limited air storage capacity, how to ensure the stability of the output power of the air turbine is a technical problem that needs to be solved urgently in this application. Summary of the invention

[0003] In view of the above shortcomings of the prior art, the object of the present invention is to provide an air turbine system and an operating method thereof that can adapt to a wide range of changes in the pressure of an air compression source. When the pressure of the air compression source changes, the connection relationship between the high-pressure air turbine, the medium-pressure air turbine and the low-pressure air turbine is switched to ensure that the sum of the power outputs of each air turbine remains unchanged.

[0004] To achieve the above and other related objectives, the present invention provides an air turbine system, which includes a compressed air source, a high-pressure air turbine, a medium-pressure air turbine, and a low-pressure air turbine; the compressed air source is communicated with the air inlet of the high-pressure air turbine through a high-pressure inlet pipe; a high-pressure supplementary air pipe and a medium-pressure supplementary air pipe are arranged in parallel on the high-pressure inlet pipe; the high-pressure supplementary air pipe is communicated with the air supplementary port of the high-pressure air turbine, and a high-pressure air supplementary valve is arranged on the high-pressure supplementary air pipe; the medium-pressure supplementary air pipe is communicated with the air inlet of the medium-pressure air turbine, and a medium-pressure air supplementary valve is arranged on the medium-pressure supplementary air pipe; a high-pressure on-off valve and a high-pressure regulating valve are arranged on the high-pressure inlet pipe, and the air inlets of the high-pressure supplementary air pipe and the medium-pressure supplementary air pipe are both located between the high-pressure on-off valve and the high-pressure regulating valve; a medium-pressure inlet pipe and a low-pressure inlet pipe are arranged in parallel at the exhaust port of the high-pressure air turbine; the medium-pressure inlet pipe is communicated with the air inlet of the medium-pressure air turbine, and a medium-pressure on-off valve and a medium-pressure regulating valve are arranged on the medium-pressure inlet pipe; the low-pressure inlet pipe is communicated with the air inlet of the low-pressure air turbine, and a first low-pressure on-off valve, a low-pressure regulating valve, and a second low-pressure on-off valve are arranged in sequence along the flow direction of the low-pressure inlet pipe; the exhaust port of the medium-pressure air turbine is communicated with the low-pressure inlet pipe through a medium-pressure exhaust pipe, and the air outlet of the medium-pressure exhaust pipe is located between the low-pressure regulating valve and the second low-pressure on-off valve; the exhaust port of the low-pressure air turbine is communicated with the atmosphere; according to the pressure drop of the compressed air source, the present invention adjusts each valve to control the connection relationship between the compressed air source, the high-pressure air turbine, the medium-pressure air turbine, and the low-pressure air turbine, so that the sum of the output powers of each air turbine remains unchanged.

[0005] Preferably, the air turbine system includes a medium-pressure heater and a low-pressure heater; the medium-pressure heater is arranged on the medium-pressure inlet pipe, and the low-pressure heater is arranged on the low-pressure inlet pipe, for heating the compressed air entering the medium-pressure air turbine and the low-pressure air turbine.

[0006] Preferably, the medium-pressure cylinder is a single-flow medium-pressure cylinder or a double-flow medium-pressure cylinder, which can be specifically determined according to the total flow rate of the air compression source.

[0007] Preferably, the air turbine system includes a generator, and the high-pressure air turbine, the medium-pressure air turbine, the low-pressure air turbine, and the generator are sequentially connected through couplings to form a series shafting to ensure that the power generation power of the generator remains unchanged.

[0008] Preferably, each air turbine is connected with a generator through a coupling to ensure that the sum of the power generation powers of each generator remains unchanged.

[0009] The present application also provides an operation method for the air turbine system, and the operation method includes the following steps:

[0010] When the pressure of the compressed air source is greater than the first preset pressure value, close the high-pressure air supplement valve, medium-pressure air supplement valve, No. 1 low-pressure on-off valve, and low-pressure regulating valve, open the high-pressure on-off valve, medium-pressure on-off valve, high-pressure regulating valve, medium-pressure regulating valve, medium-pressure heater, and low-pressure heater, make the medium-pressure regulating valve in the fully open state, and gradually increase the opening degree of the high-pressure regulating valve according to the pressure drop of the compressed air source, so that the total power generated by each air turbine remains unchanged;

[0011] When the pressure of the compressed air source is not greater than the first preset pressure value and is greater than the second preset pressure value, open the high-pressure air supplement valve, make the high-pressure regulating valve and the medium-pressure regulating valve in the fully open state, and gradually increase the opening degree of the high-pressure air supplement valve according to the pressure drop of the compressed air source, so that the total power generated by each air turbine remains unchanged;

[0012] When the pressure of the compressed air source is not greater than the second preset pressure value and is greater than the third preset pressure value, open the medium-pressure air supplement valve, make the high-pressure regulating valve, medium-pressure regulating valve, and high-pressure air supplement valve in the fully open state, and gradually increase the opening degree of the medium-pressure air supplement valve according to the pressure drop of the compressed air source, so that the total power generated by each air turbine remains unchanged;

[0013] When the pressure of the compressed air source is not greater than the third preset pressure value and is greater than the fourth preset pressure value, open the No. 1 low-pressure on-off valve, while slowly increasing the opening degree of the low-pressure regulating valve, gradually reduce the opening of the medium-pressure regulating valve, and adjust the opening of the high-pressure air supplement valve according to the pressure ratio between the inlet and air supplement ports of the high-pressure air turbine. At the same time, gradually increase the opening degree of the medium-pressure air supplement valve according to the pressure drop of the compressed air source, so that the total power generated by each air turbine remains unchanged;

[0014] When the pressure of the compressed air source is not greater than the fourth preset pressure value, close the high-pressure air supplement valve, medium-pressure regulating valve, medium-pressure on-off valve, and medium-pressure heater, and gradually increase the opening degree of the medium-pressure air supplement valve according to the pressure drop of the compressed air source until the medium-pressure air supplement valve is fully open, so that the total power generated by each air turbine remains unchanged.

[0015] Preferably, the first preset pressure value is the opening pressure value of the high-pressure air supplement valve, the second preset pressure value is the opening pressure value of the medium-pressure air supplement valve, the third preset pressure value is the critical pressure value for the occurrence of air blowing, and the fourth preset pressure value is the pressure value of the compressed air source corresponding to the switching of the medium- and high-pressure air turbines from the series-parallel state to the parallel state.

[0016] As described above, an air turbine system and an operation method of the present invention have the following beneficial effects:

[0017] The present invention overcomes the problem of the decrease in the output power of the air turbine caused by the decrease in the pressure of the compressed air source by changing the connection relationship between the high-pressure air turbine, the medium-pressure air turbine, and the low-pressure air turbine. While achieving the efficient operation of each air turbine, it ensures that the total power output by each air turbine always remains unchanged. Since the present invention has the ability to adapt to the decrease in the pressure of the compressed air source, the gas storage volume of the compressed air energy storage system can be appropriately controlled, thereby effectively controlling the investment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of an air turbine system according to an embodiment of the present invention.

[0019] Figure 2 It is a schematic diagram of an air turbine system according to an embodiment of the present invention

[0020] Figure 3 It is a flowchart of a method for operating an air turbine system.

[0021] High-pressure air turbine 1, medium-pressure air turbine 2, low-pressure air turbine 3, generator 4, high-pressure intake pipe 5, high-pressure make-up gas pipe 5a, medium-pressure make-up gas pipe 5b, medium-pressure intake pipe 6, low-pressure intake pipe 7, medium-pressure exhaust pipe 8, high-pressure on-off valve 9, high-pressure regulating valve 10, high-pressure make-up gas valve 11, medium-pressure make-up gas valve 12, medium-pressure regulating valve 13, medium-pressure on-off valve 14, medium-pressure heater 15, first low-pressure on-off valve 16, low-pressure regulating valve 17, low-pressure heater 18, second low-pressure on-off valve 19. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0023] Please refer to Figures 1 to 3 . It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in the art to understand and read, and are not used to limit the limited conditions under which the present invention can be implemented. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" used in this specification are only for the convenience of clear narration, and are not used to limit the scope under which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope under which the present invention can be implemented.

[0024] Embodiment 1

[0025] As shown in Figure 1 the figure, this embodiment provides an air turbine system, including a compressed air source, a high-pressure air turbine 1, a medium-pressure air turbine 2 and a low-pressure air turbine 3; the high-pressure air turbine 1 has an air inlet, a supplementary air inlet and an exhaust outlet; both the medium-pressure air turbine 2 and the low-pressure air turbine 3 have an air inlet and an exhaust outlet; among them, the air inlet of the high-pressure air turbine 1 is communicated with the compressed air source through a high-pressure inlet pipe 5; a high-pressure on-off valve 9 and a high-pressure regulating valve 10 are arranged on the high-pressure inlet pipe 5, the high-pressure on-off valve 9 is used to connect or cut off the high-pressure inlet pipe 5, and the high-pressure regulating valve 10 is used to regulate the flow rate of the air entering the air inlet of the high-pressure air turbine 1; a high-pressure supplementary air pipe 5a and a medium-pressure supplementary air pipe 5b are arranged in parallel on the high-pressure inlet pipe 5; the high-pressure supplementary air pipe 5a is communicated with the supplementary air inlet of the high-pressure air turbine 1, and the medium-pressure supplementary air pipe 5b is communicated with the air inlet of the medium-pressure air turbine 2; a high-pressure supplementary air valve 11 for regulating the flow rate of the air entering the supplementary air inlet of the high-pressure air turbine 1 is arranged on the high-pressure supplementary air pipe 5a, and a medium-pressure supplementary air valve 12 for regulating the flow rate of the air entering the air inlet of the medium-pressure air turbine 2 is arranged on the medium-pressure supplementary air pipe 5b; the exhaust outlet of the high-pressure air turbine 1 is divided into two branches, namely a medium-pressure inlet pipe 6 communicated with the air inlet of the medium-pressure air turbine 2 and a low-pressure inlet pipe 7 communicated with the air inlet of the low-pressure air turbine 3; a medium-pressure regulating valve 13 and a medium-pressure on-off valve 14 are arranged on the medium-pressure inlet pipe 6 to respectively control the flow rate and on-off of the medium-pressure inlet pipe 6; a first low-pressure on-off valve 16, a low-pressure regulating valve 17 and a second low-pressure on-off valve 19 are arranged in sequence along the flow direction of the low-pressure inlet pipe 7 to control the on-off and flow rate of the low-pressure inlet pipe 7; an exhaust outlet of the medium-pressure air turbine 2 is provided with a medium-pressure exhaust pipe 8 communicated with the low-pressure inlet pipe 7, and the air outlet of the medium-pressure exhaust pipe 8 is located between the low-pressure regulating valve 17 and the second low-pressure on-off valve 19; in this embodiment, the medium-pressure regulating valve 13 is preferably arranged downstream of the medium-pressure on-off valve 14.

[0026] By controlling the states of the respective valves, the respective air turbines in the air turbine system can be in different connection states, and there are a total of the following five connection states:

[0027] Status 1: Close the high-pressure air make-up valve 11, medium-pressure air make-up valve 12, first low-pressure on-off valve 16 and low-pressure regulating valve 17, open the high-pressure on-off valve 9 and medium-pressure on-off valve 14, make the medium-pressure regulating valve 13 in the fully open state (i.e., the valve opening is the largest), and gradually increase the valve opening of the high-pressure regulating valve 10 according to the pressure drop of the compressed air source; at this time, the high-pressure air turbine 1, medium-pressure air turbine 2 and low-pressure air turbine 3 form a series combination, so that the compressed air of the compressed air source enters the high-pressure air turbine 1 through the high-pressure inlet pipe 5 to do work, the exhaust of the high-pressure air turbine 1 enters the medium-pressure air turbine 2 to do work, the exhaust of the medium-pressure air turbine 2 enters the low-pressure air turbine 3 to do work, and the exhaust of the low-pressure air turbine 3 is discharged into the atmosphere; during this process, although the pressure of the compressed air source is continuously decreasing, by adjusting the opening of the high-pressure regulating valve 10, the pressure behind the high-pressure regulating valve 10 is always maintained at the flow-through design pressure, and the flow rate entering each air turbine also remains at the design flow rate, preventing the over-generation of the turbine and ensuring that the total power output by each air turbine remains unchanged.

[0028] Status 2: Close the medium-pressure air make-up valve 12, first low-pressure on-off valve 16 and low-pressure regulating valve 17, open the high-pressure on-off valve 9 and medium-pressure on-off valve 14, make the medium-pressure regulating valve 13 and high-pressure regulating valve 10 in the fully open state (i.e., the valve opening is the largest), and gradually increase the valve opening of the high-pressure air make-up valve 11 according to the pressure drop of the compressed air source; at this time, the high-pressure air turbine 1, medium-pressure air turbine 2 and low-pressure air turbine 3 still form a series combination, so that the compressed air of the compressed air source enters the high-pressure air turbine 1 through the high-pressure inlet pipe 5 and high-pressure air make-up pipe 5a to do work, the exhaust of the high-pressure air turbine 1 enters the medium-pressure air turbine 2 to do work, the exhaust of the medium-pressure air turbine 2 enters the low-pressure air turbine 3 to do work, and the exhaust of the low-pressure air turbine 3 is discharged into the atmosphere; during this process, although the pressure of the compressed air source is continuously decreasing, due to the continuous increase in the flow rate entering each air turbine, it makes up for the problem of insufficient output power caused by the decrease in compressed air pressure, ensuring that the total power output by each air turbine remains unchanged.

[0029] State three: Close the first low-pressure on-off valve 16 and the low-pressure regulating valve 17, open the high-pressure on-off valve 9 and the medium-pressure on-off valve 14, and keep the medium-pressure regulating valve 13, the high-pressure regulating valve 10, and the high-pressure air make-up valve 11 in the fully open state (i.e., the maximum valve opening state). Then, gradually increase the valve opening of the medium-pressure air make-up valve 12 according to the pressure drop of the compressed air source. At this time, the high-pressure air turbine 1 and the medium-pressure air turbine 2 form a series-parallel combination (i.e., they are connected in parallel and in series with each other). Then, this series-parallel combination is connected in series with the low-pressure air turbine 3. A part of the compressed air from the compressed air source enters the high-pressure air turbine 1 through the high-pressure intake pipe 5 and the high-pressure make-up pipe 5a to do work. A part of the compressed air from the compressed air source enters the medium-pressure air turbine 2 through the medium-pressure make-up pipe 5b together with the exhaust gas of the high-pressure air turbine 1 to do work. The exhaust gas of the medium-pressure air turbine 2 enters the low-pressure air turbine 3 to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere. During this process, although the pressure of the compressed air source is continuously decreasing, since the flow rate entering the medium-pressure air turbine and the low-pressure air turbine is still continuously increasing, it makes up for the problem of insufficient output power caused by the decrease in compressed air pressure, ensuring that the total power output by each air turbine remains unchanged.

[0030] State four: Open the high-pressure on-off valve 9, the medium-pressure on-off valve 14, and the first low-pressure on-off valve 16. During the process of slowly increasing the opening of the low-pressure regulating valve 17, gradually decrease the valve opening of the medium-pressure regulating valve 13 to avoid pressure mutation, and gradually increase the opening of the medium-pressure air make-up valve 12 according to the pressure drop of the compressed air source. At the same time, adjust the valve opening of the high-pressure air make-up valve 11 according to the pressure ratio between the intake port and the make-up port of the high-pressure air turbine 1 to avoid the occurrence of a blowing phenomenon in the flow passage section before the make-up point due to too low intake port pressure of the high-pressure air turbine 1 and improve the operating safety of the high-pressure air turbine 1. At this time, the high-pressure air turbine 1 and the medium-pressure air turbine 2 form a series-parallel combination (i.e., they are connected in parallel and in series with each other), and the high-pressure air turbine 1 and the medium-pressure air turbine 2 are respectively connected in series with the low-pressure air turbine 3. A part of the compressed air from the compressed air source enters the high-pressure air turbine 1 through the high-pressure intake pipe 5 and the high-pressure make-up pipe 5a to do work. A part of the compressed air from the compressed air source enters the medium-pressure air turbine 2 through the medium-pressure make-up pipe 5b together with a part of the exhaust gas of the high-pressure air turbine 1 to do work. The exhaust gas of the medium-pressure air turbine 2 and the other part of the exhaust gas of the high-pressure air turbine 1 enter the low-pressure air turbine 3 to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere. During this process, although the pressure of the compressed air source is continuously decreasing, since the flow rate entering the medium-pressure air turbine and the low-pressure air turbine is still continuously increasing, it makes up for the problem of insufficient output power caused by the decrease in compressed air pressure, ensuring that the total power output by each air turbine remains unchanged.

[0031] Status Five: Close the high-pressure air make-up valve 11, medium-pressure regulating valve 13, and medium-pressure on-off valve 14, open the high-pressure on-off valve 9, first low-pressure on-off valve 16, and low-pressure regulating valve 17, and gradually increase the opening degree of the medium-pressure air make-up valve 12 according to the pressure drop of the compressed air source; at this time, the high-pressure air turbine 1 and the medium-pressure air turbine 2 form a parallel combination, and this parallel combination is connected in series with the low-pressure air turbine 3, so that a part of the compressed air of the compressed air source enters the high-pressure air turbine 1 through the high-pressure intake pipe 5 to do work, a part of the compressed air of the compressed air source enters the medium-pressure air turbine 2 through the medium-pressure air make-up pipe 5b to do work, the exhaust gas of the medium-pressure air turbine 2 and the exhaust gas of the high-pressure air turbine 1 enter the low-pressure air turbine 3 together to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere; during this process, although the pressure of the compressed air source is continuously decreasing, since the flow rate entering the medium-pressure air turbine and the low-pressure air turbine is still continuously increasing, it makes up for the problem of insufficient output power caused by the decrease in compressed air pressure, ensuring that the total power output by each air turbine remains unchanged.

[0032] Furthermore, a medium-pressure heater 15 is provided on the medium-pressure intake pipe 6, and a low-pressure heater 17 is provided on the low-pressure intake pipe 7. The medium-pressure heater 15 is located upstream of the medium-pressure on-off valve 14 and is used to heat the exhaust gas entering the medium-pressure intake pipe 6; the low-pressure heater 18 is located between the outlet of the medium-pressure exhaust pipe 8 and the second low-pressure on-off valve 19 and is used to heat the exhaust gas entering the low-pressure intake pipe 7.

[0033] Furthermore, as Figure 1 shown, the air turbine system includes a generator, and the high-pressure air turbine 1, medium-pressure air turbine 2, low-pressure air turbine 3, and generator 4 are sequentially connected by couplings to form a series shafting.

[0034] Embodiment Two

[0035] As Figure 2 shown, the difference between this embodiment and Embodiment One lies only in the number and arrangement of the generators 4; in this embodiment, the number of the generators 4 is three, and the three generators 4 are connected to the high-pressure air turbine 1, medium-pressure air turbine 2, and low-pressure air turbine 3 respectively by couplings.

[0036] Embodiment Three

[0037] The difference between this embodiment and Embodiment One lies only in the structural forms and numbers of the medium-pressure cylinder 2 and the low-pressure cylinder 3, and there are specifically the following four schemes:

[0038] Scheme One: One medium-pressure cylinder 2 and one low-pressure cylinder 3 are provided respectively, and the medium-pressure cylinder 2 is a single-flow medium-pressure cylinder, and the low-pressure cylinder 3 is a single-flow low-pressure cylinder; Scheme One is applicable to a compressed air source with a relatively small flow rate.

[0039] Solution 2: One intermediate-pressure cylinder 2 and one low-pressure cylinder 3 are provided. The intermediate-pressure cylinder 2 is a single-flow intermediate-pressure cylinder, and the low-pressure cylinder 3 is a double-flow low-pressure cylinder. Solution 2 is applicable to a compressed air source with a general flow rate.

[0040] Solution 3: One intermediate-pressure cylinder 2 and one low-pressure cylinder 3 are provided. The intermediate-pressure cylinder 2 is a double-flow intermediate-pressure cylinder, and the low-pressure cylinder 3 is a double-flow low-pressure cylinder. Solution 3 is applicable to a compressed air source with a large flow rate.

[0041] Solution 4: One intermediate-pressure cylinder 2 is provided, and multiple low-pressure cylinders 3 are provided. The intermediate-pressure cylinder 2 is a single-flow intermediate-pressure cylinder, and the low-pressure cylinder 3 is a single-flow low-pressure cylinder. The multiple low-pressure cylinders 3 are connected in series with each other, and a reheater is provided between two adjacent low-pressure cylinders 3. Solution 4 is applicable to a compressed air source with a relatively high inlet pressure and a relatively low temperature.

[0042] Embodiment 4

[0043] As Figure 3 shown, this embodiment provides an operation method for an air turbine system, requiring that the sum of the powers output by the air turbine systems of Embodiment 1 or 2 within the pressure range of 10 Mpa to 3 MPa of the compressed air source is 30 MW. The operation method includes the following steps:

[0044] S1. When the pressure of the compressed air source is greater than the first preset pressure value, close the high-pressure air make-up valve 11, the intermediate-pressure air make-up valve 12, the first low-pressure on-off valve 16, and the low-pressure regulating valve 17, open the high-pressure on-off valve 9, the intermediate-pressure on-off valve 14, the high-pressure regulating valve 10, the intermediate-pressure regulating valve 13, the second low-pressure on-off valve 19, the intermediate-pressure heater 15, and the low-pressure heater 18, keep the intermediate-pressure regulating valve 13 in a fully open state, and gradually increase the opening degree of the high-pressure regulating valve 10 according to the pressure drop of the compressed air source to keep the total power generated by each air turbine unchanged;

[0045] Specifically, the first preset pressure value is the opening pressure value of the high-pressure air make-up valve 11, and this value is 8.11 MPa. In this step, the pressure of the compressed air source is always greater than the opening pressure value of the high-pressure air make-up valve 11 to ensure that the high-pressure air make-up valve 11 is always in a closed state. When the pressure of the compressed air source drops to 8.11 MPa, the high-pressure regulating valve 10 needs to be in a fully open state (i.e., the valve opening degree is the largest).

[0046] In this step, the high-pressure air turbine 1, the intermediate-pressure air turbine 2, and the low-pressure air turbine 3 form a series combination, so that the compressed air of the compressed air source enters the high-pressure air turbine 1 through the high-pressure inlet pipe 5 to do work. The exhaust gas of the high-pressure air turbine 1 enters the intermediate-pressure air turbine 2 to do work. The exhaust gas of the intermediate-pressure air turbine 2 enters the low-pressure air turbine 3 to do work. The exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere.

[0047] S2. When the pressure of the compressed air source is not greater than the first preset pressure value and is greater than the second preset pressure value, open the high-pressure air make-up valve 11, keep the high-pressure regulating valve 10 and the medium-pressure regulating valve 13 in the fully open state, and gradually increase the opening degree of the high-pressure air make-up valve 11 according to the pressure drop of the compressed air source to keep the total power generated by each air turbine unchanged;

[0048] Specifically, the second preset pressure value is the opening pressure value of the medium-pressure air make-up valve 12, and this value is 7.2 MPa; in this step, the pressure of the compressed air source is greater than 7.2 MPa and not greater than 8.11 Mpa, so that the high-pressure air make-up valve 11 is opened and the medium-pressure air make-up valve 12 remains closed; when the pressure of the compressed air source drops to 7.2 MPa, the high-pressure air make-up valve 11 needs to be in the fully open state.

[0049] In this step, the high-pressure air turbine 1, the medium-pressure air turbine 2 and the low-pressure air turbine 3 still form a series combination, so that the compressed air of the compressed air source enters the high-pressure air turbine 1 through the high-pressure intake pipe 5 and the high-pressure air make-up pipe 5a to do work, the exhaust gas of the high-pressure air turbine 1 enters the medium-pressure air turbine 2 to do work, the exhaust gas of the medium-pressure air turbine 2 enters the low-pressure air turbine 3 to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere;

[0050] S3. When the pressure of the compressed air source is not greater than the second preset pressure value and is greater than the third preset pressure value, open the medium-pressure air make-up valve 12, keep the high-pressure regulating valve 10, the medium-pressure regulating valve 13 and the high-pressure air make-up valve 11 in the fully open state, and gradually increase the opening degree of the medium-pressure air make-up valve 12 according to the pressure drop of the compressed air source to keep the total power generated by each air turbine unchanged;

[0051] Specifically, the third preset pressure value is the critical pressure value at which the flow passages before and after the air make-up point in the high-pressure air turbine 1 are about to generate a blowing phenomenon, and this pressure value is 5.3 MPa; in this step, the pressure of the compressed air source is greater than 5.3 MPa and not greater than 7.2 Mpa, so that both the high-pressure air make-up valve 11 and the medium-pressure air make-up valve 12 can be opened.

[0052] In this step, the high-pressure air turbine 1 and the medium-pressure air turbine 2 form a series-parallel combination (that is, while they are connected in parallel, they are also connected in series), and then this series-parallel combination is connected in series with the low-pressure air turbine 3, so that a part of the compressed air of the compressed air source enters the high-pressure air turbine 1 through the high-pressure intake pipe 5 and the high-pressure air make-up pipe 5a to do work, a part of the compressed air of the compressed air source enters the medium-pressure air turbine 2 through the medium-pressure air make-up pipe 5b together with the exhaust gas of the high-pressure air turbine 1 to do work, the exhaust gas of the medium-pressure air turbine 2 enters the low-pressure air turbine 3 to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere.

[0053] S4. When the pressure of the compressed air source is not greater than the third preset pressure value and is greater than the fourth preset pressure value, open the first low-pressure on-off valve 16. During the process of slowly increasing the opening degree of the low-pressure regulating valve 17, gradually reduce the valve opening degree of the medium-pressure regulating valve 13, and adjust the valve opening degree of the high-pressure air supply valve 11 according to the pressure ratio between the air inlet and the air supply port of the high-pressure air turbine 1. At the same time, gradually increase the opening degree of the medium-pressure air supply valve 12 according to the pressure drop of the compressed air source, so that the total power generated by each air turbine remains unchanged;

[0054] Specifically, the fourth preset pressure value is the pressure of the compressed air source corresponding to the full-closed state of the valve opening degree adjustment of the medium-pressure regulating valve 13, and this value is 5 MPa. Since the pressure of the compressed air source drops to 5.3 MPa, the expansion ratio of the flow passage section in front of the air supply point in the high-pressure air turbine 1 has reached the blowing critical value (that is, the ratio of the air inlet pressure to the air supply port pressure of the high-pressure air turbine reaches the blowing critical value). If the pressure of the compressed air source continues to drop, it will cause the ratio of the air inlet pressure to the air supply port pressure of the high-pressure air turbine 1 to be lower than the blowing critical value, resulting in a blowing phenomenon in the high-pressure air turbine. To overcome this defect, in this step, the valve opening degree of the high-pressure air supply valve 11 is adjusted in real time according to the pressure ratio between the air inlet and the air supply port of the high-pressure air turbine 1 (that is, increasing the air inlet pressure and decreasing the air supply port pressure), ensuring that the pressure ratio between the air inlet and the air supply port of the high-pressure air turbine 1 is always not less than the blowing critical value.

[0055] In this step, the high-pressure air turbine 1 and the medium-pressure air turbine 2 form a series-parallel combination (that is, they are connected in parallel and in series with each other), and the high-pressure air turbine 1 and the medium-pressure air turbine 2 are respectively connected in series with the low-pressure air turbine 3. A part of the compressed air of the compressed air source enters the high-pressure air turbine 1 through the high-pressure inlet pipe 5 and the high-pressure air supply pipe 5a to do work. A part of the compressed air of the compressed air source enters the medium-pressure air turbine 2 through the medium-pressure air supply pipe 5b and a part of the exhaust gas of the high-pressure air turbine 1 to do work. The exhaust gas of the medium-pressure air turbine 2 and another part of the exhaust gas of the high-pressure air turbine 1 enter the low-pressure air turbine 3 to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere.

[0056] S5. When the pressure of the compressed air source is not greater than the fourth preset pressure value, close the medium-pressure on-off valve 14, the medium-pressure regulating valve 13, the high-pressure air supply valve 11 and the medium-pressure heater 15, and gradually increase the opening degree of the medium-pressure air supply valve 12 according to the pressure drop of the compressed air source until the medium-pressure air supply valve 12 is fully open, so that the total power generated by each air turbine remains unchanged.

[0057] When the pressure value of the compressed air source drops to 3 MPa, the medium-pressure air supply valve 12 is fully open and cannot continue to supply air, indicating the end of the energy release mode.

[0058] At this step, the high-pressure air turbine 1 and the medium-pressure air turbine 2 form a parallel combination, and this parallel combination is connected in series with the low-pressure air turbine 3. A part of the compressed air from the compressed air source enters the high-pressure air turbine 1 through the high-pressure intake pipe 5 to do work. A part of the compressed air from the compressed air source enters the medium-pressure air turbine 2 through the medium-pressure supplementary air pipe 5b to do work. The exhaust gas of the medium-pressure air turbine 2 and the exhaust gas of the high-pressure air turbine 1 enter the low-pressure air turbine 3 together to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere.

[0059] Embodiment Five

[0060] As Figure 3 shown, this embodiment provides an operation method for an air turbine system, requiring that the sum of the powers output by the air turbine system of Embodiment One or Two within the pressure range of 17 Mpa to 5 MPa of the compressed air source is 100 MW; this operation method includes the following steps:

[0061] S1. When the pressure of the compressed air source is greater than the first preset pressure value, close the high-pressure supplementary air valve 11, the medium-pressure supplementary air valve 12, the first low-pressure on-off valve 16, and the low-pressure regulating valve 17, and open the high-pressure on-off valve 9, the medium-pressure on-off valve 14, the high-pressure regulating valve 10, the medium-pressure regulating valve 13, the second low-pressure on-off valve 19, the medium-pressure heater 15, and the low-pressure heater 18, make the medium-pressure regulating valve 13 in the fully open state, and gradually increase the opening degree of the high-pressure regulating valve 10 according to the pressure drop of the compressed air source, so that the total power generated by each air turbine remains unchanged;

[0062] Specifically, the first preset pressure value is the opening pressure value of the high-pressure supplementary air valve 11, and this value is 15.16 MPa; at this step, the pressure of the compressed air source is always greater than the opening pressure value of the high-pressure supplementary air valve 11, ensuring that the high-pressure supplementary air valve 11 is always in the closed state; when the pressure of the compressed air source drops to 15.16 MPa, the high-pressure regulating valve 10 needs to be in the fully open state (i.e., the valve opening degree is the largest).

[0063] At this step, the high-pressure air turbine 1, the medium-pressure air turbine 2, and the low-pressure air turbine 3 form a series combination, so that the compressed air from the compressed air source enters the high-pressure air turbine 1 through the high-pressure intake pipe 5 to do work, the exhaust gas of the high-pressure air turbine 1 enters the medium-pressure air turbine 2 to do work, the exhaust gas of the medium-pressure air turbine 2 enters the low-pressure air turbine 3 to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere.

[0064] S2. When the pressure of the compressed air source is not greater than the first preset pressure value and is greater than the second preset pressure value, open the high-pressure supplementary air valve 11, make the high-pressure regulating valve 10 and the medium-pressure regulating valve 13 in the fully open state, and gradually increase the opening degree of the high-pressure supplementary air valve 11 according to the pressure drop of the compressed air source, so that the total power generated by each air turbine remains unchanged;

[0065] Specifically, the second preset pressure value is the opening pressure value of the medium-pressure air replenishing valve 12, which is 13.5 MPa; in this step, the pressure of the compressed air source is greater than 13.5 MPa and not greater than 15.16 Mpa, so that the high-pressure air replenishing valve 11 opens, and the medium-pressure air replenishing valve 12 remains closed; when the pressure of the compressed air source drops to 13.5 MPa, the high-pressure air replenishing valve 11 needs to be fully open.

[0066] In this step, the high-pressure air turbine 1, the medium-pressure air turbine 2, and the low-pressure air turbine 3 still form a series combination, so that the compressed air of the compressed air source enters the high-pressure air turbine 1 through the high-pressure intake pipe 5 and the high-pressure air replenishing pipe 5a to do work. The exhaust gas of the high-pressure air turbine 1 enters the medium-pressure air turbine 2 to do work, the exhaust gas of the medium-pressure air turbine 2 enters the low-pressure air turbine 3 to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere;

[0067] S3. When the pressure of the compressed air source is not greater than the second preset pressure value and greater than the third preset pressure value, open the medium-pressure air replenishing valve 12, keep the high-pressure regulating valve 10, the medium-pressure regulating valve 13, and the high-pressure air replenishing valve 11 fully open, and gradually increase the opening degree of the medium-pressure air replenishing valve 12 according to the pressure drop of the compressed air source to keep the total power generated by each air turbine unchanged;

[0068] Specifically, the third preset pressure value is the critical pressure value at which the flow passage section before the air replenishing point in the high-pressure air turbine 1 is about to generate a blowing phenomenon, and this pressure value is 8.7 MPa; in this step, the pressure of the compressed air source is greater than 8.7 MPa and not greater than 13.5 Mpa, so that both the high-pressure air replenishing valve 11 and the medium-pressure air replenishing valve 12 can open.

[0069] In this step, the high-pressure air turbine 1 and the medium-pressure air turbine 2 form a series-parallel combination (that is, while they are connected in parallel, they are also connected in series), and then this series-parallel combination is connected in series with the low-pressure air turbine 3, so that a part of the compressed air of the compressed air source enters the high-pressure air turbine 1 through the high-pressure intake pipe 5 and the high-pressure air replenishing pipe 5a to do work, and a part of the compressed air of the compressed air source enters the medium-pressure air turbine 2 through the medium-pressure air replenishing pipe 5b together with the exhaust gas of the high-pressure air turbine 1 to do work. The exhaust gas of the medium-pressure air turbine 2 enters the low-pressure air turbine 3 to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere.

[0070] S4. When the pressure of the compressed air source is not greater than the third preset pressure value and greater than the fourth preset pressure value, open the first low-pressure on-off valve 16. During the process of slowly increasing the opening degree of the low-pressure regulating valve 17, gradually reduce the valve opening degree of the medium-pressure regulating valve 13, and adjust the valve opening degree of the high-pressure air replenishing valve 11 according to the pressure ratio between the air intake port and the air replenishing port of the high-pressure air turbine 1. At the same time, gradually increase the opening degree of the medium-pressure air replenishing valve 12 according to the pressure drop of the compressed air source to keep the total power generated by each air turbine unchanged;

[0071] Specifically, the fourth preset pressure value is the pressure of the compressed air source corresponding to the minimum opening of the medium-pressure regulating valve 13. This value is 8.4 MPa. Since the pressure of the compressed air source has dropped to 8.4 MPa, the expansion ratio of the flow passage section in front of the air supply point in the high-pressure air turbine 1 has reached the blowing critical value (i.e., the ratio of the inlet pressure to the air supply port pressure of the high-pressure air turbine reaches the blowing critical value). If the pressure of the compressed air source continues to drop, it will cause the ratio of the inlet pressure to the air supply port pressure of the high-pressure air turbine 1 to be lower than the blowing critical value, resulting in a blowing phenomenon. To overcome this defect, in this step, the opening of the high-pressure air supply valve 11 is adjusted in real time according to the pressure ratio between the inlet and air supply ports of the high-pressure air turbine 1 (i.e., increasing the inlet pressure and decreasing the air supply port pressure) to ensure that the pressure ratio between the inlet and air supply ports of the high-pressure air turbine 1 is always not less than the blowing critical value.

[0072] In this step, the high-pressure air turbine 1 and the medium-pressure air turbine 2 form a series-parallel combination (i.e., they are arranged in parallel and in series with each other). Moreover, the high-pressure air turbine 1 and the medium-pressure air turbine 2 are respectively connected in series with the low-pressure air turbine 3, so that a part of the compressed air from the compressed air source enters the high-pressure air turbine 1 through the high-pressure inlet pipe 5 and the high-pressure air supply pipe 5a to do work. A part of the compressed air from the compressed air source enters the medium-pressure air turbine 2 through the medium-pressure air supply pipe 5b and a part of the exhaust gas of the high-pressure air turbine 1 to do work. The exhaust gas of the medium-pressure air turbine 2 and another part of the exhaust gas of the high-pressure air turbine 1 enter the low-pressure air turbine 3 to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere.

[0073] S5. When the pressure of the compressed air source is not greater than the fourth preset pressure value, close the medium-pressure regulating valve 13, the medium-pressure on-off valve 14, the high-pressure air supply valve 11, and the medium-pressure heater 15, and gradually increase the opening of the medium-pressure air supply valve 12 according to the pressure drop of the compressed air source until the medium-pressure air supply valve 12 is fully opened, so that the total power generated by each air turbine remains unchanged.

[0074] When the pressure value of the compressed air source drops to 5 MPa, the medium-pressure air supply valve 12 is fully opened and cannot continue to supply air, indicating the end of the energy release mode.

[0075] In this step, the high-pressure air turbine 1 and the medium-pressure air turbine 2 form a parallel combination, and this parallel combination is connected in series with the low-pressure air turbine 3, so that a part of the compressed air from the compressed air source enters the high-pressure air turbine 1 through the high-pressure inlet pipe 5 to do work. A part of the compressed air from the compressed air source enters the medium-pressure air turbine 2 through the medium-pressure air supply pipe 5b to do work. The exhaust gas of the medium-pressure air turbine 2 and the exhaust gas of the high-pressure air turbine 1 enter the low-pressure air turbine 3 to do work, and the exhaust gas of the low-pressure air turbine 3 is discharged into the atmosphere.

[0076] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. An air turbine system, characterized in that, It includes a compressed air source, a high-pressure air turbine, a medium-pressure air turbine, and a low-pressure air turbine; the compressed air source is communicated with the air inlet of the high-pressure air turbine through a high-pressure inlet pipe; a high-pressure supplementary air pipe and a medium-pressure supplementary air pipe are arranged in parallel on the high-pressure inlet pipe; the high-pressure supplementary air pipe is communicated with the air supplementary port of the high-pressure air turbine, and a high-pressure air supplementary valve is arranged on the high-pressure supplementary air pipe; the medium-pressure supplementary air pipe is communicated with the air inlet of the medium-pressure air turbine, and a medium-pressure air supplementary valve is arranged on the medium-pressure supplementary air pipe; a high-pressure on-off valve and a high-pressure regulating valve are arranged on the high-pressure inlet pipe, and the air inlets of the high-pressure supplementary air pipe and the medium-pressure supplementary air pipe are both located between the high-pressure on-off valve and the high-pressure regulating valve; a medium-pressure inlet pipe and a low-pressure inlet pipe are arranged in parallel at the exhaust port of the high-pressure air turbine; the medium-pressure inlet pipe is communicated with the air inlet of the medium-pressure air turbine, and a medium-pressure on-off valve and a medium-pressure regulating valve are arranged on the medium-pressure inlet pipe; the low-pressure inlet pipe is communicated with the air inlet of the low-pressure air turbine, and a first low-pressure on-off valve, a low-pressure regulating valve, and a second low-pressure on-off valve are arranged in sequence along the flow direction of the low-pressure inlet pipe; the exhaust port of the medium-pressure air turbine is communicated with the low-pressure inlet pipe through a medium-pressure exhaust pipe, and the air outlet of the medium-pressure exhaust pipe is located between the low-pressure regulating valve and the second low-pressure on-off valve; the exhaust port of the low-pressure air turbine is communicated with the atmosphere.

2. The air turbine system according to claim 1, characterized in that, The air turbine system includes a medium-pressure heater and a low-pressure heater; the medium-pressure heater is arranged on the medium-pressure inlet pipe, and the low-pressure heater is arranged on the low-pressure inlet pipe.

3. An air turbine system according to claim 1 or 2, characterized in that, The medium-pressure air turbine is a single-flow medium-pressure cylinder or a double-flow medium-pressure cylinder.

4. An air turbine system according to claim 1 or 2, characterized in that, The air turbine system includes a generator, and the high-pressure air turbine, the medium-pressure air turbine, the low-pressure air turbine, and the generator are sequentially connected through couplings to form a series shafting.

5. An air turbine system according to claim 1 or 2, characterized in that, Each air turbine is connected with a generator through a coupling.

6. A method for operating the air turbine system according to claim 2, characterized in that This operation method includes the following steps: When the pressure of the compressed air source is greater than the first preset pressure value, close the high-pressure air supplementary valve, the medium-pressure air supplementary valve, the first low-pressure on-off valve, and the low-pressure regulating valve, open the high-pressure on-off valve, the medium-pressure on-off valve, the high-pressure regulating valve, the medium-pressure regulating valve, the second low-pressure on-off valve, the medium-pressure heater, and the low-pressure heater, make the medium-pressure regulating valve in a fully open state, and gradually increase the opening degree of the high-pressure regulating valve according to the pressure drop of the compressed air source to keep the total power generated by each air turbine unchanged; When the pressure of the compressed air source is not greater than the first preset pressure value and is greater than the second preset pressure value, open the high-pressure air supplementary valve, make the high-pressure regulating valve and the medium-pressure regulating valve in a fully open state, and gradually increase the opening degree of the high-pressure air supplementary valve according to the pressure drop of the compressed air source to keep the total power generated by each air turbine unchanged; When the pressure of the compressed air source is not greater than the second preset pressure value and is greater than the third preset pressure value, open the medium-pressure air supplementary valve, make the high-pressure regulating valve, the medium-pressure regulating valve, and the high-pressure air supplementary valve in a fully open state, and gradually increase the opening degree of the medium-pressure air supplementary valve according to the pressure drop of the compressed air source to keep the total power generated by each air turbine unchanged; When the pressure of the compressed air source is not greater than the third preset pressure value and is greater than the fourth preset pressure value, open the first low-pressure on-off valve. While slowly increasing the opening degree of the low-pressure regulating valve, gradually decrease the valve opening degree of the medium-pressure regulating valve, and adjust the valve opening degree of the high-pressure air make-up valve according to the pressure ratio between the air inlet and the air make-up port of the high-pressure air turbine. At the same time, gradually increase the opening degree of the medium-pressure air make-up valve according to the pressure drop of the compressed air source, so that the total power generated by each air turbine remains unchanged; When the pressure of the compressed air source is not greater than the fourth preset pressure value, close the high-pressure air make-up valve, the medium-pressure on-off valve, the medium-pressure regulating valve and the medium-pressure heater, and gradually increase the opening degree of the medium-pressure air make-up valve according to the pressure drop of the compressed air source until the medium-pressure air make-up valve is fully open, so that the total power generated by each air turbine remains unchanged.

7. The operating method according to claim 6, characterized in that The first preset pressure value is the opening pressure value of the high-pressure air make-up valve, the second preset pressure value is the opening pressure value of the medium-pressure air make-up valve, the third preset pressure value is the critical pressure value at which blowing is about to occur, and the fourth preset pressure value is the pressure value of the compressed air source corresponding to the switching of the medium- and high-pressure air turbines from the series-parallel state to the parallel state.

Images