An internal combustion engine and micro gas turbine combined cycle system

Abstract

The present invention relates to the technical field of power plants, and particularly to a combined cycle system of an internal combustion engine and a micro gas turbine, which includes a turbocharged internal combustion engine system and a micro gas turbine system. The turbocharged internal combustion engine system and the micro gas turbine system are connected through a first heat exchanger and a bypass cooling system. The present invention provides a combined cycle system of an internal combustion engine and a micro gas turbine with a simple structural design, which makes full use of the exhaust gas after the turbine of the internal combustion engine and has a high thermal efficiency of the micro gas turbine.

Description

Technical Field

[0001] The present invention relates to the technical field of power devices, and particularly to a combined cycle system of an internal combustion engine and a micro gas turbine. Background Art

[0002] Internal combustion engines and micro gas turbines are important power devices and have important applications in the fields of vehicles, ships, construction machinery, agricultural machinery and power generation. However, with the continuous increase in the market inventory of power devices, the emissions of greenhouse gases are also increasing year by year, and the resulting global warming problem has become a global problem that cannot be ignored. In this context, how to improve the thermal efficiency of internal combustion engines and micro gas turbines has become an important way to reduce carbon emissions. Combustion and aerodynamic optimization of internal combustion engines and micro gas turbines are important technical means to improve their respective thermal efficiencies. At present, a large number of basic and engineering research works have been carried out and important progress has been made. However, this technology has become increasingly mature, and it is very difficult to further achieve a large increase in thermal efficiency on this technical route. If the combined cycle of two power machines can be used to make full use of the heat exchange characteristics according to the characteristics of their respective thermodynamic cycles, thereby improving the thermal efficiency of the entire power system, it is a technical means to reduce the carbon emissions of power machines. Summary of the Invention

[0003] The object of the present invention is to overcome the defects and deficiencies existing in the prior art, and to provide a combined cycle system of an internal combustion engine and a micro gas turbine with a simple structural design, which makes full use of the exhaust gas after the turbine of the internal combustion engine and has a high thermal efficiency of the micro gas turbine.

[0004] The technical solution for achieving the object of the present invention is: a combined cycle system of an internal combustion engine and a micro gas turbine, including a turbocharged internal combustion engine system and a micro gas turbine system, wherein the turbocharged internal combustion engine system and the micro gas turbine system are connected through a first heat exchanger and a bypass cooling system.

[0005] Further, the turbocharged internal combustion engine system includes an internal combustion engine, a first turbocharger and an intercooler, and the internal combustion engine, the first turbocharger and the intercooler are connected through pipelines to form a closed-loop circuit.

[0006] Further, the micro gas turbine system includes a combustion chamber, a second heat exchanger and a second turbocharger, and the second heat exchanger is connected to the combustion chamber and the second turbocharger through pipelines to form a closed-loop circuit.

[0007] Further, the first heat exchanger is arranged on the pipeline between the second heat exchanger and the second turbocharger, and the first heat exchanger is connected to the first turbocharger through a pipeline.

[0008] Furthermore, the bypass cooling system is arranged between the intercooler and the second turbocharger. The bypass cooling system includes a bypass pipeline and an electronically controlled valve arranged on the pipeline of the bypass pipeline. The two ends of the bypass pipeline are respectively connected to the intercooler and the second turbocharger.

[0009] After adopting the above technical solution, the present invention has the following positive effects:

[0010] (1) By arranging the first heat exchanger on the pipeline between the second heat exchanger and the second compressor, and connecting the first heat exchanger to the first turbine through a pipeline, the internal energy of the gas after the turbine of the internal combustion engine is transferred to the intake air of the micro gas turbine, so that the waste gas energy after the turbine of the internal combustion engine can be utilized, increasing the intake air temperature of the combustion chamber of the micro gas turbine. According to the basic principle of the Brayton thermodynamic cycle of the micro gas turbine, the purpose of improving the thermal efficiency of the micro gas turbine can be achieved.

[0011] (2) By arranging a bypass cooling system between the intercooler and the second turbine, a part of the fresh air cooled by the intercooler of the internal combustion engine is extracted and introduced to the second turbine end of the micro gas turbine to cool the blades of the second turbine, thereby improving the reliability of the turbine blades of the micro gas turbine, and allowing the turbine inlet temperature of the micro gas turbine to be increased. According to the basic principle of the Brayton thermodynamic cycle of the micro gas turbine, the thermal efficiency of the micro gas turbine can be further improved. Description of the Drawings

[0012] In order to make the content of the present invention easier and clearer to understand, the following further detailed description of the present invention is made according to specific embodiments in conjunction with the drawings, where:

[0013] Figure 1 is a schematic structural diagram of the present invention.

[0014] In the figure: turbocharged internal combustion engine system 1, internal combustion engine 11, first turbocharger 12, first compressor 121, first turbine 122, intercooler 13, crankshaft 14, outlet pipeline 15, first intake pipeline 16, micro gas turbine system 2, combustion chamber 21, second heat exchanger 22, second turbocharger 23, rotating shaft 24, second intake pipeline 25, second compressor 231, second turbine 232, cooling mechanism 2321, first heat exchanger 3, bypass cooling system 4, bypass pipeline 41, electronically controlled valve 42. Detailed Embodiments

[0015] As Figure 1As shown in the figure, a combined cycle system of an internal combustion engine and a micro gas turbine includes a turbocharged internal combustion engine system 1 and a micro gas turbine system 2. The turbocharged internal combustion engine system 1 includes an internal combustion engine 11, a first turbocharger 12 and an intercooler 13. The first turbocharger 12 is composed of a first compressor 121 and a first turbine 122. The internal combustion engine 11, the first turbocharger 12 and the intercooler 13 are connected by pipelines to form a closed-loop circuit. The micro gas turbine system 2 includes a combustion chamber 21, a second heat exchanger 22 and a second turbocharger 23. The second turbocharger 23 is composed of a second compressor 231 and a second turbine 232. The second heat exchanger 22 is connected to the combustion chamber 21 and the second turbocharger 23 by pipelines respectively to form a closed-loop circuit. A first heat exchanger 3 is provided on the pipeline between the second heat exchanger 22 and the second compressor 231 of the second turbocharger 23. The first heat exchanger 3 is connected to the first turbine 122 of the first turbocharger 12 by a pipeline. By arranging the first heat exchanger 3 on the pipeline between the second heat exchanger 22 and the second compressor 231 and connecting the first heat exchanger 3 to the first turbine 122 by a pipeline, the energy of the exhaust gas after the turbine of the internal combustion engine 11 is transferred to the intake air of the micro gas turbine, so that the energy of the exhaust gas after the turbine of the internal combustion engine 11 can be utilized while the thermal efficiency of the micro gas turbine is improved. A bypass cooling system 4 is also provided between the intercooler 13 and the second turbine 232 of the second turbocharger 23. The bypass cooling system 4 includes a bypass pipeline 41 and an electronically controlled valve 42 provided on the pipeline of the bypass pipeline 41. The two ends of the bypass pipeline 41 are respectively connected to the cooling mechanism 2321 on the intercooler 13 and the second turbine 232. By arranging the bypass cooling system 4 between the intercooler 13 and the second turbine 232, a part of the fresh air cooled by the intercooler 13 of the internal combustion engine 11 is extracted and introduced to the second turbine 232 end of the micro gas turbine for cooling the blades of the second turbine 232, thereby improving the thermal efficiency of the micro gas turbine. The setting of the electronically controlled valve 42 can adjust the working state of the bypass cooling system 4 according to the requirements of the operating conditions of the combined cycle system: when the combined cycle system operates under low conditions, the combustion temperature of the micro gas turbine is relatively low, and the second turbine 232 can meet the reliability requirements, the electronically controlled valve 42 is closed, and the bypass cooling system 4 does not work; when the combined cycle system operates under high conditions, the exhaust gas temperature of the micro gas turbine is very high. At this time, in order to reduce the thermal load of the second turbine 232, the electronically controlled valve 42 can be opened, so that a part of the cooled fresh air in the pipeline after the intercooler 13 enters the bypass pipeline 41, and then the second turbine 232 is cooled through the cooling structure 2321 on the second turbine 232, thereby improving the reliability of the micro gas turbine.

[0016] The turbocharged internal combustion engine system 1 is fueled by the internal combustion engine 11. After combustion, the engine outputs power to the outside through the crankshaft 14. The exhaust gas enters the first turbine 122 through the pipeline to expand and do work. The exhaust gas that works through the first turbine 122 converts internal energy into mechanical energy on the one hand, which is used to drive the first compressor 121 to rotate and do work. On the other hand, the exhaust gas energy that has not been fully utilized is transferred to the fresh air after the second compressor 232. When the general engine is running at high working conditions, the exhaust temperature after the first turbine 122 can reach 550-650°C. After the first compressor 121 obtains the mechanical energy transmitted by the first turbine 122, it rotates and compresses the air to do work. The fresh air is sucked into the first compressor 121 through the pipeline, and the mechanical energy of the first compressor 121 is converted into pressure energy and internal energy in the first compressor 121. Since the air in the outlet pipeline 15 after the first compressor 121 is compressed by the first compressor 121, it has a higher pressure and temperature. The internal combustion engine thermal system that follows the Sabade basic thermodynamic cycle needs to reduce the air temperature in the first intake pipe 16 as much as possible in order to increase the intake volume per unit time of the internal combustion engine 11, thereby increasing the power density and efficiency. Therefore, an intercooler 13 is added to the pipeline after the first compressor 121 to cool the intake air of the engine. At the same time, the fuel burns in the combustion chamber 21, and the high-temperature and high-pressure gas after combustion enters the second heat exchanger 22 through the pipeline, and then enters the second turbine 232 through the pipeline to expand and do work. The high-temperature and high-pressure gas converts pressure energy and internal energy into mechanical energy in the second turbine 232. On the one hand, the mechanical energy is used to drive the second compressor 231 to compress air and do work, and on the other hand, the remaining power is output to the outside through the rotating shaft 24 of the second turbine 232. Fresh air is sucked into the second compressor 231 through the pipeline, and then the mechanical energy is converted into the pressure energy and internal energy of the fresh air. The compressed fresh air enters the first heat exchanger 3 through the pipeline and mixes with the exhaust gas that has not been fully utilized after the turbine of the internal combustion engine 11. The mixed gas is heated by the first heat exchanger 3 and the second heat exchanger 22 at two stages, so that the temperature in the second intake pipe 25 is increased to a higher level, thereby meeting the direction of improving the thermal efficiency of the Brayton cycle, thereby improving the thermal efficiency of the micro gas turbine. It should be noted that although the thermal efficiency of the internal combustion engine 11 in the combined cycle system is not improved, the thermal efficiency of the micro gas turbine is improved by using the working mode of the internal combustion engine 11 to exchange heat with the micro gas turbine, thereby improving the thermal efficiency of the combined cycle system.

[0017] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An internal combustion engine and micro gas turbine combined cycle system, characterized in that: It includes a turbocharged internal combustion engine system (1) and a micro gas turbine system (2), and the turbocharged internal combustion engine system (1) and the micro gas turbine system (2) are connected through a first heat exchanger (3) and a bypass cooling system (4); The turbocharged internal combustion engine system (1) includes an internal combustion engine (11), a first turbocharger (12) and an intercooler (13), and the internal combustion engine (11), the first turbocharger (12) and the intercooler (13) are connected by pipelines to form a closed loop; The micro gas turbine system (2) includes a combustion chamber (21), a second heat exchanger (22) and a second turbocharger (23), and the second heat exchanger (22) is connected to the combustion chamber (21) and the second turbocharger (23) respectively by pipelines to form a closed loop; The first heat exchanger (3) is arranged on the pipeline between the second heat exchanger (22) and the second turbocharger (23), and the first heat exchanger (3) is connected to the first turbocharger (12) through a pipeline.

2. The internal combustion engine and micro gas turbine combined cycle system according to claim 1, characterized in that: The bypass cooling system (4) is arranged between the intercooler (13) and the second turbocharger (23), and the bypass cooling system (4) includes a bypass pipeline (41) and an electronically controlled valve (42) arranged on the pipeline of the bypass pipeline (41), and both ends of the bypass pipeline (41) are respectively connected to the intercooler (13) and the second turbocharger (23).

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