阅读说明：本技术 一种超临界二氧化碳朗肯循环系统及联合循环系统 (Supercritical carbon dioxide Rankine cycle system and combined cycle system ) 是由 陈宜 徐东杰 陈铮 徐小东 于 2018-08-13 设计创作，主要内容包括：本发明提供一种超临界二氧化碳朗肯循环系统及联合循环系统,该超临界二氧化碳朗肯循环系统包括：第一加热器；第二加热器,第二加热器的烟气入口与第一加热器的烟气出口连通,第二加热器的工质出口与第一加热器的工质入口连通；回热器,回热器的冷流体出口和第一加热器的工质入口连通,回热器的热流体出口与冷却系统的入口连接；二氧化碳循环泵,二氧化碳循环泵的工质出口分别与回热器的冷流体入口及第二加热器的工质入口连通；二氧化碳透平,二氧化碳透平的入口与第一加热器的工质出口连通,二氧化碳透平的出口与回热器的热流体入口连通；与所二氧化碳透平连接的第一发电机；以及冷凝器。这样,可以使联合循环系统的结构比较简单和紧凑。(The invention provides a supercritical carbon dioxide Rankine cycle system and a combined cycle system, wherein the supercritical carbon dioxide Rankine cycle system comprises: a first heater; the flue gas inlet of the second heater is communicated with the flue gas outlet of the first heater, and the working medium outlet of the second heater is communicated with the working medium inlet of the first heater; a cold fluid outlet of the heat regenerator is communicated with a working medium inlet of the first heater, and a hot fluid outlet of the heat regenerator is connected with an inlet of the cooling system; a working medium outlet of the carbon dioxide circulating pump is respectively communicated with a cold fluid inlet of the heat regenerator and a working medium inlet of the second heater; an inlet of the carbon dioxide turbine is communicated with a working medium outlet of the first heater, and an outlet of the carbon dioxide turbine is communicated with a hot fluid inlet of the heat regenerator; a first generator coupled to the carbon dioxide turbine; and a condenser. In this way, the combined cycle system can be made relatively simple and compact in construction.)

1. A supercritical carbon dioxide Rankine cycle system, characterized by comprising:

a first heater;

the flue gas inlet of the second heater is communicated with the flue gas outlet of the first heater, and the working medium outlet of the second heater is communicated with the working medium inlet of the first heater;

the cold fluid outlet of the heat regenerator is communicated with the working medium inlet of the first heater;

a working medium outlet of the carbon dioxide circulating pump is respectively communicated with a cold fluid inlet of the heat regenerator and a working medium inlet of the second heater;

an inlet of the carbon dioxide turbine is communicated with a working medium outlet of the first heater, and an outlet of the carbon dioxide turbine is communicated with a hot fluid inlet of the heat regenerator;

a first generator coupled to the carbon dioxide turbine;

and a working medium inlet of the condenser is communicated with a hot fluid outlet of the heat regenerator, and a working medium outlet of the condenser is communicated with a working medium inlet of the carbon dioxide circulating pump.

2. The supercritical carbon dioxide rankine cycle system of claim 1, further comprising:

a solar reflector;

and the heat absorption pipe is arranged on the solar reflector, the inlet of the heat absorption pipe is communicated with the outlet of the carbon dioxide circulating pump, and the outlet of the heat absorption pipe is communicated with the working medium inlet of the first heater.

3. The supercritical carbon dioxide rankine cycle system of claim 1, further comprising:

the inlet of the seawater circulating pump is communicated with the ocean, and the outlet of the seawater circulating pump is communicated with the seawater inlet of the condenser;

wherein, the seawater outlet of the condenser is communicated with the ocean.

4. A combined cycle system, comprising:

the gas turbine circulating system comprises a compressor, a combustion chamber, a gas turbine and a second generator, wherein the combustion chamber is respectively communicated with the compressor and the gas turbine, and the gas turbine is respectively connected with the compressor and the second generator;

and a flue gas inlet of the supercritical carbon dioxide Rankine cycle system is communicated with an outlet of the gas turbine.

5. The combined cycle system of claim 4, wherein the supercritical carbon dioxide rankine cycle system comprises:

a flue gas inlet of the first heater is communicated with an outlet of the gas turbine, and the flue gas inlet of the first heater is a flue gas inlet of the supercritical carbon dioxide Rankine cycle system;

the flue gas inlet of the second heater is communicated with the flue gas outlet of the first heater, and the working medium outlet of the second heater is communicated with the working medium inlet of the first heater;

the cold fluid outlet of the heat regenerator is communicated with the working medium inlet of the first heater;

a working medium outlet of the carbon dioxide circulating pump is respectively communicated with a cold fluid inlet of the heat regenerator and a working medium inlet of the second heater;

an inlet of the carbon dioxide turbine is communicated with a working medium outlet of the first heater, and an outlet of the carbon dioxide turbine is communicated with a hot fluid inlet of the heat regenerator;

a first generator coupled to the carbon dioxide turbine;

and a working medium inlet of the condenser is communicated with a hot fluid outlet of the heat regenerator, and a working medium outlet of the condenser is communicated with a working medium inlet of the carbon dioxide circulating pump.

6. The combined cycle system of claim 5, wherein the supercritical carbon dioxide rankine cycle system further comprises:

a solar reflector;

and the heat absorption pipe is arranged on the solar reflector, the inlet of the heat absorption pipe is communicated with the outlet of the carbon dioxide circulating pump, and the outlet of the heat absorption pipe is communicated with the working medium inlet of the first heater.

7. The combined cycle system of claim 6, wherein the solar reflector is a parabolic trough reflector or a linear Fresnel reflector.

8. The combined cycle system of claim 5, wherein the supercritical carbon dioxide rankine cycle system further comprises:

the inlet of the seawater circulating pump is communicated with the ocean, and the outlet of the seawater circulating pump is communicated with the seawater inlet of the condenser;

wherein, the seawater outlet of the condenser is communicated with the ocean.

Technical Field

The invention relates to the technical field of power generation, in particular to a supercritical carbon dioxide Rankine cycle system and a combined cycle system.

Background

With the continuous development of power generation technology, the combined cycle technology is greatly popularized and applied. The combined cycle is a combined working system consisting of thermodynamic cycle systems with different working media, and when the combined cycle is used for generating power, the waste gas generated by the previous stage is used for driving the next stage of heat engine to push the generator, so that the efficiency of fuel can be greatly improved, and the generated energy is improved. Generally, the existing combined cycle system mainly consists of a gas turbine system and a steam Rankine cycle system; however, the combined cycle using such a structure is relatively large and complex.

Disclosure of Invention

The embodiment of the invention aims to provide a supercritical carbon dioxide Rankine cycle system and a combined cycle system, and solves the problems that an existing combined cycle system is large in structure and complex.

To achieve the above object, an embodiment of the present invention provides a supercritical carbon dioxide rankine cycle system, including:

a first heater;

the flue gas inlet of the second heater is communicated with the flue gas outlet of the first heater, and the working medium outlet of the second heater is communicated with the working medium inlet of the first heater;

the cold fluid outlet of the heat regenerator is communicated with the working medium inlet of the first heater;

a working medium outlet of the carbon dioxide circulating pump is respectively communicated with a cold fluid inlet of the heat regenerator and a working medium inlet of the second heater;

an inlet of the carbon dioxide turbine is communicated with a working medium outlet of the first heater, and an outlet of the carbon dioxide turbine is communicated with a hot fluid inlet of the heat regenerator;

a first generator coupled to the carbon dioxide turbine;

and a working medium inlet of the condenser is communicated with a hot fluid outlet of the heat regenerator, and a working medium outlet of the condenser is communicated with a working medium inlet of the carbon dioxide circulating pump.

Optionally, the supercritical carbon dioxide rankine cycle system further includes:

a solar reflector;

and the heat absorption pipe is arranged on the solar reflector, the inlet of the heat absorption pipe is communicated with the outlet of the carbon dioxide circulating pump, and the outlet of the heat absorption pipe is communicated with the working medium inlet of the first heater.

Optionally, the supercritical carbon dioxide rankine cycle system further includes:

the inlet of the seawater circulating pump is communicated with the ocean, and the outlet of the seawater circulating pump is communicated with the seawater inlet of the condenser;

wherein, the seawater outlet of the condenser is communicated with the ocean.

An embodiment of the present invention further provides a combined cycle system, including:

the gas turbine circulating system comprises a compressor, a combustion chamber, a gas turbine and a second generator, wherein the combustion chamber is respectively communicated with the compressor and the gas turbine, and the gas turbine is respectively connected with the compressor and the second generator;

and a flue gas inlet of the supercritical carbon dioxide Rankine cycle system is communicated with an outlet of the gas turbine.

Optionally, the supercritical carbon dioxide rankine cycle system includes:

a flue gas inlet of the first heater is communicated with an outlet of the gas turbine, and the flue gas inlet of the first heater is a flue gas inlet of the supercritical carbon dioxide Rankine cycle system;

the flue gas inlet of the second heater is communicated with the flue gas outlet of the first heater, and the working medium outlet of the second heater is communicated with the working medium inlet of the first heater;

the cold fluid outlet of the heat regenerator is communicated with the working medium inlet of the first heater;

a working medium outlet of the carbon dioxide circulating pump is respectively communicated with a cold fluid inlet of the heat regenerator and a working medium inlet of the second heater;

an inlet of the carbon dioxide turbine is communicated with a working medium outlet of the first heater, and an outlet of the carbon dioxide turbine is communicated with a hot fluid inlet of the heat regenerator;

a first generator coupled to the carbon dioxide turbine;

and a working medium inlet of the condenser is communicated with a hot fluid outlet of the heat regenerator, and a working medium outlet of the condenser is communicated with a working medium inlet of the carbon dioxide circulating pump.

Optionally, the supercritical carbon dioxide rankine cycle system further includes:

a solar reflector;

and the heat absorption pipe is arranged on the solar reflector, the inlet of the heat absorption pipe is communicated with the outlet of the carbon dioxide circulating pump, and the outlet of the heat absorption pipe is communicated with the working medium inlet of the first heater.

Optionally, the solar reflector is a parabolic trough reflector or a linear fresnel reflector.

Optionally, the supercritical carbon dioxide rankine cycle system further includes:

the inlet of the seawater circulating pump is communicated with the ocean, and the outlet of the seawater circulating pump is communicated with the seawater inlet of the condenser;

wherein, the seawater outlet of the condenser is communicated with the ocean.

One of the above technical solutions has the following advantages or beneficial effects:

according to the embodiment of the invention, the supercritical carbon dioxide Rankine cycle system and the gas turbine cycle system form the combined cycle system, and the supercritical carbon dioxide Rankine cycle system adopts supercritical carbon dioxide as a working medium, so that the combined cycle system is simpler and more compact in structure.

Drawings

Fig. 1 is a schematic structural diagram of a combined cycle system according to an embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1, an embodiment of the present invention provides a supercritical carbon dioxide rankine cycle system 1 including:

a first heater 11;

a flue gas inlet of the second heater 12 is communicated with a flue gas outlet of the first heater 11, and a working medium outlet of the second heater 12 is communicated with a working medium inlet of the first heater 11;

a cold fluid outlet of the heat regenerator 13 is communicated with a working medium inlet of the first heater 11;

a working medium outlet of the carbon dioxide circulating pump 14 is respectively communicated with a cold fluid inlet of the heat regenerator 13 and a working medium inlet of the second heater 12;

the inlet of the carbon dioxide turbine 15 is communicated with the working medium outlet of the first heater 11, and the outlet of the carbon dioxide turbine 15 is communicated with the hot fluid inlet of the heat regenerator 13;

a first generator 16 connected to the carbon dioxide turbine 15;

and a working medium inlet of the condenser 17 is communicated with a hot fluid outlet of the heat regenerator 13, and a working medium outlet of the condenser 17 is communicated with a working medium inlet of the carbon dioxide circulating pump 14.

In this embodiment, the first heater 11, the second heater 12, the regenerator 13, and the condenser 17 are all heat exchangers. Specifically, the first heater 11 and the second heater 12 are mainly used for heating the supercritical carbon dioxide working medium, and a flue gas inlet of the first heater 11 can be used for communicating with a flue gas outlet of other thermodynamic cycle systems so as to recycle flue gas coming out of other thermodynamic cycle systems; and the smoke discharged from the other thermodynamic cycle system can be discharged through the smoke outlet of the second heater 12. The heat regenerator 13 is mainly used for recovering heat energy, and the condenser 17 is mainly used for taking away heat of the gas working medium so as to completely condense the gas working medium.

In addition, the supercritical carbon dioxide circulation system 1 adopts the carbon dioxide circulation pump 14, and compared with a compressor in a Brayton circulation system, the supercritical carbon dioxide circulation system can reduce the equipment investment and reduce the power consumption of the pressurization of the circulating working medium; in addition, the temperature of the working medium on the outlet side of the carbon dioxide circulating pump 14 is low, and the temperature of the discharged smoke of the system can be reduced to the lowest, so that the waste heat of the smoke can be recovered to the maximum extent.

It should be noted that the rankine cycle system is a thermodynamic cycle system using water vapor as a working medium, and the thermodynamic cycle system can be used as a bottom cycle in a combined cycle system; the supercritical carbon dioxide Rankine cycle system 1 is a thermodynamic cycle system using supercritical carbon dioxide as a working medium. Wherein the supercritical carbon dioxide is a carbon dioxide fluid with temperature and pressure higher than critical values; which is between the physical and chemical properties of gas and liquid. The supercritical carbon dioxide has high energy density and good compressibility, thereby greatly saving space, being beneficial to improving the space utilization rate of energy-using equipment such as ships and warships, reducing the initial investment of the equipment and being easy to install and maintain. Furthermore, the supercritical carbon dioxide circulating working medium has temperature slippage phenomenon in the heating process, so that the supercritical carbon dioxide circulating working medium can be well matched with sensible heat sources such as flue gas and the like.

The working process of the supercritical carbon dioxide Rankine cycle system 1 may be: the first heater 11 is communicated with a flue gas outlet of a gas turbine in a gas turbine circulating system, so that the exhaust gas of the gas turbine system sequentially passes through the first heater 11 and the second heater 12 to realize the gradient utilization of the flue gas waste heat. In the supercritical carbon dioxide circulation system 1, a supercritical carbon dioxide working medium is subjected to pressure increase by the carbon dioxide circulation pump 14 and then is divided into two streams, wherein one stream flows through the heat regenerator 13 to absorb the exhaust heat of the carbon dioxide turbine 15, and the other stream flows through the second heater 12 to absorb the low-temperature waste heat of the flue gas discharged to the second heater 12 from the gas turbine system; then, the two heated supercritical carbon dioxide working fluid streams are merged and converged into the first heater 11, and are further heated to a high-temperature and high-pressure state; and the supercritical carbon dioxide working medium heated to the high temperature and the high pressure enters the carbon dioxide turbine 15 to expand and do work so as to drive the first generator 16 to generate power. The exhaust gas from the carbon dioxide turbine 15 passes through the regenerator 13 to recover heat, and the exhaust gas from the regenerator 13 enters the condenser 17 to be condensed and converted into liquid carbon dioxide, so as to start the next cycle.

Therefore, the working medium flow of the regenerator 13 on the cold fluid side can be reduced, and the problem of low heat exchange efficiency of cold and hot fluids in the regenerator 13 due to large specific heat capacity difference is solved; in addition, the fluid flowing through the second heater 12 and branched by the carbon dioxide circulating pump 14 can realize deep gradient utilization of the waste heat of the flue gas of the gas turbine system, and the temperature of the discharged flue gas of the system is reduced, so that the utilization amount of the waste heat is increased, and the power generation amount is improved.

Optionally, the supercritical carbon dioxide rankine cycle system 1 further includes:

a solar reflector 18;

and a heat absorption pipe 19 arranged on the solar reflector 18, wherein an inlet of the heat absorption pipe 19 is communicated with an outlet of the carbon dioxide circulating pump 14, and an outlet of the heat absorption pipe 19 is communicated with a working medium inlet of the first heater 11.

Wherein the solar reflector 18 may be a plurality of solar reflectors, thereby forming a solar reflector field. In addition, the solar reflector 18 may be a parabolic trough reflector or a linear fresnel reflector, and other solar reflectors may be used according to different system design parameters, which is not limited herein. Note that the heat absorbing pipe 19 may be a tubular member that absorbs solar radiation energy and transfers heat to the heat transfer medium.

The solar reflector 18 and the heat absorption pipe 19 can form a solar collector system to collect medium and low temperature solar heat energy through condensation, so as to heat part of supercritical carbon dioxide working medium of the supercritical carbon dioxide system, and thus, the solar collector system can be used as an auxiliary driving heat source of the supercritical carbon dioxide Rankine cycle system 1.

In this way, the supercritical carbon dioxide working medium pressurized by the carbon dioxide circulating pump 14 can also be divided into a flow to enter the heat absorption pipe 19 to absorb the medium-low temperature solar heat energy, so that the high-efficiency power generation of the medium-low temperature solar energy is realized by means of the supercritical carbon dioxide rankine cycle system 1.

Optionally, the supercritical carbon dioxide rankine cycle system 1 further includes:

a seawater circulating pump 110, an inlet of the seawater circulating pump 110 is communicated with the ocean, and an outlet of the seawater circulating pump 110 is communicated with a seawater inlet of the condenser 17;

wherein the seawater outlet of the condenser 17 is communicated with the ocean.

In the present embodiment, since the critical pressure and temperature of carbon dioxide are 7.38MPa and 31.1 ℃ respectively, and the condensation temperature of the supercritical carbon dioxide rankine cycle system 1 is generally 20 to 25 ℃, such a condensation temperature is generally difficult to obtain, and thus has a large influence on the stable operation of the system. The water depth of coastal subsurface in China is usually between 10 and 300 meters, the temperature is between 12 and 20 ℃, and even can be as low as 6 to 12 ℃, so that the natural cold source is a good natural cold source of a supercritical carbon dioxide circulation system.

Seawater can be pumped by the seawater circulating pump 110 to serve as a low-temperature cold source of the supercritical carbon dioxide, so that the supercritical carbon dioxide circulating working medium in the supercritical carbon dioxide Rankine cycle system 1 is completely condensed, the exhaust pressure of a turbine can be effectively reduced, the work load per unit working medium flow is increased, and the power generation efficiency of the supercritical carbon dioxide circulating system is improved. In the process, only a little electric energy needs to be additionally increased for the seawater circulating pump 110, and the natural cold source has stable temperature.

In this embodiment, the working medium outlet of the carbon dioxide circulating pump 14 is respectively communicated with the cold fluid inlet of the heat regenerator 13 and the working medium inlet of the second heater 12, so that the carbon dioxide pressurized by the carbon dioxide circulating pump 14 can be divided into two streams, one stream passes through the heat regenerator 13 to recover the exhaust heat of the carbon dioxide turbine 15, and the other stream enters the second heater 12 to recover the low-temperature waste heat in the flue gas of the gas turbine; therefore, the waste heat utilization amount of the combined cycle system can be increased, and the power generation amount is improved.

As shown in fig. 1, an embodiment of the present invention further provides a combined cycle system, including:

a gas turbine circulation system 2, which includes a compressor 21, a combustion chamber 22, a gas turbine 23 and a second generator 24, wherein the combustion chamber 22 is respectively communicated with the compressor 21 and the gas turbine 23, and the gas turbine 23 is respectively connected with the compressor 21 and the second generator 24;

a supercritical carbon dioxide Rankine cycle system 1, wherein a flue gas inlet of the supercritical carbon dioxide Rankine cycle system 1 is communicated with an outlet of the gas turbine 23.

Wherein, in the combined cycle system, the gas turbine cycle system 22 is a topping cycle system, and the supercritical carbon dioxide rankine cycle system 1 is a bottoming cycle system. The gas turbine system 2 realizes the input of fuel chemical energy and the output of mechanical power and flue gas waste heat through the combustion of fuel and air, the mechanical power drives a generator to generate electricity, and the flue gas waste heat can be used as a driving heat source of the supercritical carbon dioxide Rankine cycle.

In this embodiment, the combined cycle system is formed by the supercritical carbon dioxide rankine cycle system and the gas turbine cycle system, and the supercritical carbon dioxide rankine cycle system uses supercritical carbon dioxide as a working medium, so that the combined cycle system has a relatively simple and compact structure.

Optionally, the supercritical carbon dioxide rankine cycle system 1 includes:

a first heater 11, wherein a flue gas inlet of the first heater 11 is communicated with an outlet of the gas turbine 23, and a flue gas inlet of the first heater 11 is a flue gas inlet of the supercritical carbon dioxide Rankine cycle system 1;

a flue gas inlet of the second heater 12 is communicated with a flue gas outlet of the first heater 11, and a working medium outlet of the second heater 12 is communicated with a working medium inlet of the first heater 11;

a cold fluid outlet of the heat regenerator 13 is communicated with a working medium inlet of the first heater 11;

a working medium outlet of the carbon dioxide circulating pump 14 is respectively communicated with a cold fluid inlet of the heat regenerator 13 and a working medium inlet of the second heater 12;

the inlet of the carbon dioxide turbine 15 is communicated with the working medium outlet of the first heater 11, and the outlet of the carbon dioxide turbine 15 is communicated with the hot fluid inlet of the heat regenerator 13;

a first generator 16 connected to the carbon dioxide turbine 15;

and a working medium inlet of the condenser 17 is communicated with a hot fluid outlet of the heat regenerator 13, and a working medium outlet of the condenser 17 is communicated with a working medium inlet of the carbon dioxide circulating pump 14.

The description of the supercritical carbon dioxide rankine cycle system 1 has been detailed in the first embodiment, and is not repeated here to avoid redundancy.

Thus, by respectively communicating the working medium outlet of the carbon dioxide circulating pump 14 with the cold fluid inlet of the heat regenerator 13 and the working medium inlet of the second heater 12, the carbon dioxide pressurized by the carbon dioxide circulating pump 14 can be divided into two streams, one stream passes through the heat regenerator 13 to recover the exhaust heat of the carbon dioxide turbine 15, and the other stream enters the second heater 12 to recover the low-temperature waste heat in the flue gas of the gas turbine; therefore, the waste heat utilization amount of the combined cycle system can be increased, and the power generation amount is improved.

Optionally, the supercritical carbon dioxide rankine cycle system 1 further includes:

a solar reflector 18;

and a heat absorption pipe 19 arranged on the solar reflector 18, wherein an inlet of the heat absorption pipe 19 is communicated with an outlet of the carbon dioxide circulating pump 14, and an outlet of the heat absorption pipe 19 is communicated with a working medium inlet of the first heater 11.

The description of the solar reflector 18 and the heat absorbing pipe 19 has been detailed in the first embodiment, and is not repeated herein to avoid repetition.

In this way, the supercritical carbon dioxide working medium pressurized by the carbon dioxide circulating pump 14 can be further divided into one flow to enter the heat absorption pipe 19 to absorb the medium-low temperature solar heat energy, so that the power generation efficiency of the supercritical carbon dioxide rankine cycle system 1 is further improved.

Optionally, the solar reflector 18 is a parabolic trough reflector or a linear fresnel reflector; this may provide for lower maintenance and cleaning costs. Of course, the solar reflector may also be other reflectors, and may be specifically designed according to parameters of the system, which is not limited thereto.

Optionally, the supercritical carbon dioxide rankine cycle system 1 further includes:

a seawater circulating pump 110, an inlet of the seawater circulating pump 110 is communicated with the ocean, and an outlet of the seawater circulating pump 110 is communicated with a seawater inlet of the condenser 17;

wherein the seawater outlet of the condenser 17 is communicated with the ocean.

In this embodiment, the description of the seawater circulation pump 110 has been described in detail in the first embodiment, and is not repeated herein for avoiding redundancy.

Therefore, the seawater can be used as the low-temperature cold source of the supercritical carbon dioxide by the seawater circulating pump 110, and the seawater circulating pump 110 is additionally used for improving extremely small electric energy, so that the supercritical carbon dioxide working medium can be completely condensed finally, the power generation efficiency is improved, and the temperature of the cold source is stable.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.