WO2018224054A1 - Waste heat recovery system, method therefor and power station - Google Patents

Abstract

A waste heat recovery system, comprising N circulation loops in which gas/liquid phase variable media circulate, N being an integer greater than or equal to 1. When N is 1, a first circulation loop comprises a waste heat exchanger, a first stage steam turbine or a first stage expander, a first stage condenser and a first stage liquid pump which are sequentially connected from end to end. When N is an integer greater than or equal to 2, an Nth circulation loop comprises an N-1 stage condenser, an N stage steam turbine or an N stage expander, an N stage condenser and an N stage liquid pump which are sequentially connected from end to end, the N-1 stage condenser being configured to cause an Nth medium flowing through the Nth circulation loop to cool an Nth-1 medium outputted by an N-1 stage steam turbine or an N-1 stage expander, the N stage condenser being configured to cool the Nth-1 medium outputted by the N stage steam turbine or the N stage expander, the N stage condenser being configured to cool the Nth medium outputted by the N stage steam turbine or the N stage expander. A first medium of the first circulation loop is a low temperature liquid medium, and the Nth medium is a low temperature liquid medium having a boiling point of less than 0 degrees Celsius under standard atmospheric pressure. The system effectively utilises waste latent heat energy in the waste heat exchanger, and reduces energy waste. Also provided are a waste heat recovery method suitable for the waste heat recovery system, and a power station.

Description

Waste heat recovery system and method thereof and power station

Cross-reference to related applications

This application claims the priority of the Chinese Patent Application No. 201710434055.7, entitled "Residual Heat Recovery System and Its Method and Power Station", submitted to the Chinese Patent Office on June 9, 2017, the entire contents of which are incorporated herein by reference. In the application.

Technical field

The present application relates to waste heat utilization, and in particular to a waste heat recovery utilization system and method thereof and a power station.

Background technique

With the shortage of energy around the world, countries are committed to energy conservation, emission reduction, and strive for sustainable development. Based on the fact that energy is scarce, the issue of waste heat recovery has become an increasingly important energy effort.

The existing waste heat recovery and utilization efficiency is low, and the latent heat energy in the waste heat cannot be well utilized, resulting in a large amount of waste heat of waste heat.

Summary of the invention

The purpose of the present application includes providing a waste heat recovery utilization system to solve the technical problem of a large waste of latent heat energy of waste heat existing in the prior art.

The purpose of the present application includes providing a waste heat recovery utilization method to solve the technical problem that a large amount of latent heat energy of waste heat existing in the prior art is wasted.

The object of the present application also includes providing a power station to solve the technical problem of a large waste of latent heat energy of waste heat existing in the prior art.

Based on the above first object, the waste heat recovery utilization system provided by the present application includes N circulation loops through which a gas-liquid phase change medium flows; wherein N is an integer greater than or equal to 1;

When N is 1, the first circulation circuit includes a residual heat exchanger that is connected in series from the beginning to the end, a first-stage steam turbine or a first-stage expander, a first-stage condenser, and a first-stage liquid pump;

When N is an integer greater than or equal to 2, the Nth cycle includes an N-1 stage condenser, an N-stage turbine or an N-stage expander, an N-stage condenser, and an N-stage liquid pump that are sequentially connected end to end; The condenser is configured to cool the N-1 medium outputted by the N-1 stage steam turbine or the N-1 stage expander through the Nth medium flowing through the Nth circulation loop;

The N-stage condenser is configured to cool an N-th medium outputted by an N-stage steam turbine or an N-stage expander;

The first medium of the first circulation loop is a cryogenic liquid medium; the Nth medium is a cryogenic liquid medium having a boiling point below 0 degrees Celsius at a standard atmospheric pressure.

Further, when N is an integer greater than or equal to 2, the flow of the cryogenic liquid medium in the adjacent circulation loop is reversed.

Further, the waste heat recovery utilization system includes three circulation loops, which are a first circulation loop, a second circulation loop, and a third circulation loop, and the first circulation loop includes a residual heat exchanger, a first-stage steam turbine or a first-to-end communication. a stage expander, a first stage condenser and a first stage liquid pump; the second circulation circuit comprises a first stage condenser, a secondary or secondary expander, a secondary condenser and a secondary liquid pump which are connected in series from end to end; The circuit includes a secondary condenser, a three-stage or a three-stage expander, a three-stage condenser, and a three-stage liquid pump that are connected in series from end to end.

Further, the waste heat recovery and utilization system includes a refrigeration cycle in which a gas-liquid phase change medium flows;

The refrigeration cycle includes the N-stage condenser, a compressor, a heat exchanger, and an expansion valve that are sequentially connected end to end;

The N-stage condenser is configured to cool the N-stage medium outputted by the N-stage steam turbine or the N-stage expander by the refrigerant flowing through the refrigeration cycle;

The compressor is configured to compress a refrigerant medium and to cool the refrigerant medium through the heat exchanger to be delivered to the expansion valve.

Further, the heat exchanger is disposed between the N-stage liquid pump and the N-1 stage condenser, and a pipeline between the heat exchanger and the N-1 stage condenser is disposed a heat exchange exhaust valve configured as an exhaust gas;

a compressed inlet liquid separator is connected between the N-stage condenser and the compressor; the compressed inlet liquid separator is configured to separate the refrigerant medium of the refrigeration cycle, and deliver the refrigerant medium in the gas phase to the Compressor

a cooling and cryogenic working medium memory is connected between the expansion valve and the heat exchanger;

a refrigerating liquid separator is connected between the heat exchanger and the refrigerating cryogenic working fluid; the refrigerating liquid separator is configured to separate the refrigerating medium of the refrigerating circuit, and deliver the refrigerant in a liquid phase to The refrigeration low temperature working fluid storage device;

A refrigerating storage inlet valve is disposed between the refrigerating cryogenic refrigerant and the refrigerating liquid separator; and a refrigerating storage outlet valve is disposed between the expansion valve and the refrigerating cryogenic refrigerant.

Further, the waste heat recovery system includes a cooling straight line;

The cooling straight-discharge line includes a cooling straight-line cryogenic working fluid sequentially connected, the N-stage condenser and a cooling straight-line output end;

The N-stage condenser is configured to cool the N-stage medium outputted by the N-stage steam turbine or the N-stage expander by cooling the in-line medium in the cooled in-line cryogenic working medium, and deliver the same to the cooling straight The discharge output is discharged.

Further, a cooling in-line liquid pump is disposed between the cooling in-line cryogenic refrigerant storage medium and the N-stage condenser, and the cooling in-line liquid pump is configured to cause the cooling in the straight-line cryogenic working medium storage Cooling the straight discharge medium to the N-stage condenser;

a cooling storage outlet valve is disposed between the cooled in-line cryogenic working fluid reservoir and the cooled in-line liquid pump;

The cooling straight discharge output is provided with a cooling straight discharge valve.

Further, the cooling in-line medium is a combustible medium;

The cooled straight discharge output is in communication with a combustion chamber of the boiler.

Further, the residual heat exchanger comprises one or more of an air seawater heat exchanger, a waste heat condenser, a device cooling system waste heat recovery device, a hot water waste liquid high temperature flue gas residual heat exchanger, and a boiler;

When the residual heat exchanger includes an air seawater heat exchanger, the air seawater heat exchanger is provided with a deicing defrosting device and a fan device; the deicing defrosting device can provide the outer casing of the air seawater heat exchanger Heat, the fan device is configured to accelerate seawater or air flowing through the air seawater heat exchanger.

Further, the residual heat exchanger comprises an air seawater heat exchanger, a waste heat condenser, a equipment cooling system waste heat recovery device, a hot water waste liquid high temperature flue gas residual heat exchanger and a boiler, the air seawater heat exchanger and the waste heat condenser The equipment cooling system waste heat recovery device, the hot water waste liquid high temperature flue gas residual heat exchanger and the boiler are connected in series or in parallel.

Further, the residual heat exchanger comprises a hot water waste liquid high temperature flue gas residual heat exchanger, and the hot water waste liquid high temperature flue gas residual heat exchanger is disposed in the flue.

Further, when N is an integer greater than or equal to 1, an N-stage cryogenic working memory configured to store the Nth medium is disposed between the N-stage condenser and the N-stage liquid pump;

An N-stage condensing pump is connected between the N-stage condenser and the N-stage cryogenic refrigerant reservoir; the N-stage condensing pump is configured to input an N-th medium flowing through the N-stage condenser to the N Level low temperature working fluid storage;

An N-stage liquid separator is connected between the N-stage condenser and the N-stage condensate pump; the N-stage liquid separator is configured to separate the N-th medium of the N-th recycle loop, and is in a liquid phase The Nth medium is delivered to the N-stage condensate pump;

An N-stage memory inlet valve is disposed between the N-stage condensate pump and the N-stage low temperature working fluid storage; an N-stage memory outlet valve is disposed between the N-stage liquid pump and the N-stage low temperature working fluid storage;

The N-stage cryogenic refrigerant memory is provided with an N-stage memory compensation exhaust valve; the N-stage memory compensation exhaust valve is configured to compensate or discharge the medium in the N-stage cryogenic refrigerant memory;

The N-stage condenser is provided with an N-stage condensation compensation exhaust valve; the N-stage condensation compensation exhaust valve is configured to compensate or discharge the medium in the N-stage condenser;

The N-stage steam turbine and the N-stage condenser are integrated devices, or the N-stage expander and the N-stage condenser are integrated devices;

The Nth circulation circuit is provided with one or more circulation circuit discharge valves, and the circulation circuit discharge valve is configured to discharge the medium in the Nth circulation circuit;

The N-stage steam turbine or the N-stage expander, the N-stage condenser and the N-stage liquid pump are jacketed with an insulation layer;

When N is an integer greater than or equal to 2, the boiling point of the Nth medium is not higher than the boiling point of the N-1 medium;

The first medium is water, carbon dioxide, ammonia, helium, hydrogen, oxygen, argon, nitrogen, freon, methane, ethane, propane, natural gas, coal gas or biogas;

When N is an integer greater than or equal to 2, the Nth medium is carbon dioxide, ammonia, helium, hydrogen, oxygen, argon, nitrogen, freon, methane, ethane, propane, natural gas, coal gas or biogas;

When N is an integer greater than or equal to 1, the N-stage turbine or the N-stage expander is driven to connect an N-stage generator or a mechanical device.

Further, when N is 1, in the first circulation loop, a first-stage auxiliary heat exchanger is disposed between the residual heat exchanger and the first-stage steam turbine or the first-stage expander;

When N is an integer greater than or equal to 2, an N-stage auxiliary heat exchanger is disposed between the N-1 stage condenser and the N-stage steam turbine or the N-stage expander in the N-th circulation circuit.

Further, the circulation circuit discharge valve is disposed at an output end or an input end of the N-stage steam turbine or the N-stage expander.

Based on the above second object, the waste heat recovery utilization method provided by the present application is applicable to a waste heat recovery utilization system, and the waste heat recovery utilization system includes three circulation loops, which are a first circulation loop, a second circulation loop, and a third circulation loop in sequence. The process of waste heat recovery is as follows:

The first medium in the first circulation loop is delivered to the residual heat exchanger,

In the residual heat exchanger, the temperature of the high temperature to be cooled from 30 ° C to 800 ° C after the heat exchange with the first medium is lowered to 5 ° C - 30 ° C, and the temperature of the first medium is increased to 2 ° C - 10 ° C after the endothermic vaporization. , the pressure rises above 1.5MPa and is delivered to the first stage turbine or the first stage expander;

After the first medium drives the first-stage steam turbine or the first-stage expander to rotate work, the temperature falls below -35 ° C, the pressure drops below 0.1 MPa and is sent to the primary condenser;

The first medium is cooled to below -50 ° C in the primary condenser, and is separated by a primary liquid separator and the first medium in the liquid phase is sent to the first-stage cryogenic working storage through the primary condensing pump. Forming a first circulation loop;

In the second circulation loop, the second medium having a temperature lower than -50 ° C is sent to the primary condenser.

In the first-stage condenser, the temperature of the first medium and the second medium of the first-stage steam turbine or the first-stage expander having a temperature of -20 ° C or less is lower than -50 ° C after heat exchange, and the second medium absorbs heat and vaporizes. After the temperature rises above -70 ° C, the pressure rises above 1.5 MPa and is sent to the secondary steam turbine or the secondary expander;

After the second medium drives the secondary steam turbine or the secondary expander to rotate, the temperature drops below about -90 ° C, the pressure drops below about 0.1 MPa, and is delivered to the secondary condenser;

The second medium is cooled in the secondary condenser to a temperature below about -100 ° C, separated by a secondary liquid separator, and the second medium in the liquid phase is transported to the secondary cryogenic working medium through the secondary condensing pump Forming a second circulation loop;

In the third circulation loop, the third medium having a temperature lower than -150 ° C is transported from the tertiary low temperature working medium reservoir to the secondary condenser;

In the secondary condenser, the temperature of the second medium of the output of the secondary steam turbine or the secondary expander below -90 ° C is reduced to -100 ° C after heat exchange with the third medium, while the third medium is vaporized by heat. The temperature is raised to -115 ° C, the pressure is raised to 1.5 MPa or more and sent to a three-stage steam turbine or a three-stage expander;

After the third medium drives the three-stage steam turbine or the third-stage expander to rotate work, the temperature falls below -140 ° C, the pressure drops below about 0.1 MPa, and is sent to the third-stage condenser;

The third medium is cooled to below -150 ° C in the tertiary condenser, and is separated by a three-stage liquid separator and the third medium in the liquid phase is sent to the tertiary low temperature working medium through the tertiary condensing pump. A third circulation loop is formed.

Based on the above third object, the power station provided by the present application includes the waste heat recovery utilization system.

The waste heat recovery utilization system and method thereof provided by the present application, through the N circulation loops through which the gas-liquid phase change medium flows, and the N-1 grade condenser make the Nth-stage medium flowing through the Nth circulation loop cool the N-1 stage steam turbine Or the N-1 medium output from the N-1 grade expander adopts a low temperature liquid medium (at a pressure of one atmosphere) whose boiling point temperature is lower than 0 degrees Celsius, so that each circulation loop completes isentropic compression and isostatic heating according to the Rankine cycle theory. , isentropic expansion, isobaric condensation; equal pressure condensation in the first-stage Rankine cycle in the low temperature field by using a lower temperature medium than the boiling temperature of the previous medium (at one atmosphere), ie, the previous stage Isobaric condensation is an isobaric heating process of the latter-stage Rankine cycle. Under certain conditions, the latent heat of evaporation in the previous Rankine cycle can be fully converted into the rotary mechanical energy output of a steam turbine or expander; The circuit can theoretically significantly improve the efficiency of converting the residual heat of the residual heat exchanger in the waste heat recovery system into rotational mechanical energy, thus effectively utilizing the residual heat exchanger to some extent. The latent heat thermal energy, reducing waste heat energy wasting a lot of latent heat.

The power station provided by the present application, including the waste heat recovery and utilization system, can effectively utilize the latent heat energy of the residual heat in the residual heat exchanger, and reduce the waste of latent heat energy of the waste heat.

DRAWINGS

In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings to be used in the specific embodiments or the description of the prior art will be briefly described below, and obviously, the attached in the following description The drawings are some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

1 is a schematic diagram of a first process of a waste heat recovery and utilization system according to an embodiment of the present application;

2 is a schematic diagram of a second process of a waste heat recovery and utilization system according to an embodiment of the present application;

3 is a schematic diagram of a third process of a waste heat recovery and utilization system according to an embodiment of the present application;

4 is a schematic flow chart of a residual heat exchanger of a waste heat recovery and utilization system according to an embodiment of the present application.

Icon: 101-excess heat exchanger; 1011-air seawater heat exchanger; 10111-de-icing defroster; 10112-fan unit; 1012-reheat condenser; 1013-equipment cooling system waste heat recovery unit; 1014-hot water waste liquid High temperature flue gas residual heat exchanger; 1015-boiler; 102-first stage steam turbine; 103-stage first stage condenser; 1031-stage first stage condensing compensation exhaust valve; 104-stage liquid separator; 105-stage condensate pump; - primary low temperature working fluid storage; 1061 - primary storage inlet valve; 1062 - primary storage outlet valve; 1063 - primary storage compensation exhaust valve; 107 - primary liquid pump; 108 - primary generator;

202-secondary steam turbine; 203-secondary condenser; 204-secondary liquid separator; 205-secondary condensate pump; 206-secondary low temperature working fluid storage; 2061-secondary memory inlet valve; 2062-secondary memory Outlet valve; 207-secondary liquid pump; 208-secondary generator;

302-three-stage steam turbine; 303-three-stage condenser; 304-three-stage liquid separator; 305-three-stage condensate pump; 306-three-stage low temperature working fluid storage; 3061-three-stage memory inlet valve; 3062-three-stage memory Export valve; 307-three-stage liquid pump; 308-three-stage generator;

401-compressor; 402-heat exchanger; 405-expansion valve; 407-compressed inlet liquid separator; 408-cooled straight-line cryogenic working fluid; 4081-cooling storage outlet valve; 409-cooled straight-discharge liquid pump; - Cooling straight discharge valve; 501 - heat exchange exhaust valve; 502 - circulation circuit discharge valve.

detailed description

The technical solutions of the present application are clearly and completely described in the following with reference to the accompanying drawings. It is obvious that the described embodiments are a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present application without departing from the inventive scope are the scope of the present application.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. The orientation or positional relationship of the indications is based on the orientation or positional relationship shown in the drawings, and is merely for the convenience of the description and the simplified description, and does not indicate or imply that the device or component referred to has a specific orientation, in a specific orientation. Construction and operation are therefore not to be construed as limiting the application. Moreover, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present application, it should be noted that the terms "installation", "connected", and "connected" are to be understood broadly, and may be fixed or detachable, for example, unless otherwise specifically defined and defined. Connected, or integrally connected; can be mechanical or electrical; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of the two components. The specific meanings of the above terms in the present application can be understood in the specific circumstances for those skilled in the art.

As shown in FIG. 1 to FIG. 4, the present embodiment provides a waste heat recovery and utilization system; FIG. 1 to FIG. 3 are schematic diagrams of a first flow chart to a third flow of the waste heat recovery and utilization system provided in the embodiment; FIG. A schematic flow chart of the residual heat exchanger provided in this embodiment.

Referring to Figures 1 to 4, the waste heat recovery and utilization system (hereinafter referred to as the system) provided in this embodiment is suitable for recycling existing chemical plants, building materials, cement, paper, printing and dyeing, textile, sugar, food, wine, Low-quality thermal energy waste heat in the cooling water and refrigeration system of the pharmaceutical factory, as well as the slag water of the rolling mill, the groundwater of the oil well, the drainage, the waste heat of the steel making, the iron making and the coke oven, and the residual heat of the boiler cooling water. Boiler flue gas, diesel engine exhaust, and residual heat of gas turbine exhaust gas are suitable for utilizing a large amount of heat energy contained in air or seawater.

The waste heat recovery system includes N circulation loops through which a gas-liquid phase change medium flows; wherein N is an integer greater than or equal to 1. Wherein N may be 1, 2, 3, 4, 5, etc., for example.

When N is 1, the first circulation loop includes a residual heat exchanger 101, a first-stage steam turbine 102 or a primary expander, a primary condenser 103, and a primary liquid pump 107 that are sequentially connected end to end; alternatively, the first circulation loop The first medium is a gas-liquid phase change medium. Optionally, the primary liquid pump 107 delivers the first medium flowing through the primary condenser 103 to the residual heat exchanger 101, and after the first medium is subjected to heat exchange with the residual heat of the residual heat exchanger 101, the first medium is heated up to be all Or part of the gaseous state, that is, the first medium is converted into all or part of the gaseous state by all or part of the liquid endotherm. In certain circumstances, the first medium is capable of forming a high pressure, thereby enabling the primary turbine 102 or the primary expander to perform work. Optionally, the primary steam turbine 102 or the primary expander is driven to connect to the primary generator 108 to convert the residual heat energy of the residual heat exchanger 101 into the electrical energy of the primary generator 108 to improve the power generation efficiency. In addition, the primary turbine 102 or the primary expander can also be driven to connect other rotating instruments. Optionally, the first medium of the first circulation loop is a cryogenic liquid medium having a boiling point lower than 0 degrees Celsius; the first circulation loop adopts a low temperature liquid medium having a boiling point temperature lower than zero degrees Celsius (at one atmosphere), according to the Rankine cycle theory. Isentropic compression, isobaric heating, isentropic expansion, isobaric condensation.

When N is an integer greater than or equal to 2, the Nth cycle includes an N-1 stage condenser, an N-stage turbine or an N-stage expander, an N-stage condenser, and an N-stage liquid pump that are sequentially connected in series. The N-1 stage condenser is used to cool the N-1 medium output from the N-1 stage steam turbine or the N-1 stage expander through the Nth medium flowing through the Nth recycle loop. Optionally, the N-stage liquid pump delivers the Nth medium flowing through the N-stage condenser to the N-1 stage condenser, and in the N-1 stage condenser, the Nth medium exchanges heat with the N-1 medium. The temperature of the first N-1 medium is completely or partially liquid, that is, the N-1 medium is converted into all or part of the liquid state by all or part of the gaseous exothermic heat, and the temperature of the Nth medium is all or part of the gaseous state, that is, the Nth medium is present. All or part of the liquid endotherm is converted to all or part of the gaseous state. In certain circumstances, the Nth medium can form a high pressure, thereby enabling the N-stage turbine or the N-stage expander to perform work. Optionally, the N-stage steam turbine or the N-stage expander is driven to connect the N-stage generator to convert the thermal energy of the N-1 medium flowing through the N-1 stage condenser into the electric energy of the N-stage generator to a certain extent. Improve power generation efficiency. In addition, N-stage turbines or N-stage expanders can also be driven to connect other rotating instruments. Optionally, the Nth medium of the Nth recycle loop is a cryogenic liquid medium having a boiling point lower than 0 degrees Celsius; and the Nth recycle loop adopts a cryogenic liquid medium having a boiling point temperature below zero degrees Celsius (at one atmosphere), according to the Rankine cycle theory. Isentropic compression, isobaric heating, isentropic expansion, isobaric condensation.

The N-stage condenser is used to cool the Nth medium output from the N-stage turbine or the N-stage expander. That is, when the system includes a circulation loop, the primary condenser is used to cool the first medium output of the primary steam turbine or the primary expander; when the system includes two circulation loops, the secondary condenser is used to cool the secondary steam turbine or The second medium output by the secondary expander.

Referring to FIG. 4, optionally, the residual heat exchanger 101 includes an air seawater heat exchanger 1011, a residual heat condenser 1012, an equipment cooling system waste heat recovery unit 1013, a hot water waste liquid high temperature flue gas residual heat exchanger 1014, and a boiler 1015. One or more. The boiler 1015 includes a general boiler and a waste heat boiler. Optionally, when the residual heat exchanger 101 includes the hot water waste liquid high temperature flue gas residual heat exchanger 1014, the hot water waste liquid high temperature flue gas residual heat exchanger 1014 is disposed in the cooling utilization pipeline, for example, hot water waste liquid high temperature flue gas. The residual heat exchanger 1014 is disposed in the flue, and N circulating circuits through which the gas-liquid phase change medium flows are used to recover waste heat and waste heat of the flue.

Optionally, when the residual heat exchanger 101 includes the air seawater heat exchanger 1011, the air seawater heat exchanger 1011 is provided with a deicing defrosting device 10111 and a fan device 10112; the deicing defrosting device 10111 can supply the air seawater heat exchanger The outer casing of 1011 provides heat, and fan unit 10112 is used to accelerate seawater or air flowing through air seawater heat exchanger 1011. By the deicing defrosting device 10111, when frost is present on the air seawater heat exchanger 1011, it can be quickly removed. For example, the outer casing of the air seawater heat exchanger 1011 is provided with a deicing defrosting device 10111, or the interior of the air seawater heat exchanger 1011 is provided with a deicing defrosting device 10111, or other parts of the air seawater heat exchanger 1011 are provided. There is a deicing and defrosting device 10111. Preferably, the deicing defrosting device 10111 includes an electric heating wire; preferably, the air seawater heat exchanger 1011 has a plurality of fins and the like to improve the heat exchange efficiency of the air seawater heat exchanger 1011. The fan unit 10112 is configured to force air or seawater to accelerate and increase through the air seawater heat exchanger 1011 to increase the heat exchange efficiency of the air seawater heat exchanger 1011. Optionally, the number of fan devices 10112 is one or more sets.

Optionally, the first medium is an inorganic low temperature medium or an organic low temperature medium. Alternatively, the first medium has a boiling point above or below 0 ° C (at one atmosphere). The first medium may be, for example, water, carbon dioxide, ammonia, helium, hydrogen, oxygen, argon, nitrogen, freon, methane, ethane, propane, natural gas, coal gas or biogas; of course, the first medium may also be other low temperature. medium. Preferably, the first medium is water, carbon dioxide or ammonia. The boiling point temperature of carbon dioxide or ammonia is moderate, the pressure generated during the application of waste heat power generation is moderate, and the technical application is relatively mature. In addition, carbon dioxide is non-toxic, free from impurities, has no irritating taste, no combustion and explosion, does not support combustion, and its cost and price are relatively low.

Optionally, the boiling point of the Nth medium is not higher than the boiling point of the N-1 medium, so that the Nth medium cools the N-1 medium in the N-1 stage condenser. Optionally, the Nth medium is an inorganic low temperature medium or an organic low temperature medium. Optionally, the Nth medium is a cryogenic liquid medium having a boiling point below 0 degrees Celsius at standard atmospheric pressure. Alternatively, the Nth medium has a boiling point below -30 °C. Wherein, when N is an integer greater than or equal to 2, the Nth medium may be, for example, carbon dioxide, ammonia, helium, hydrogen, oxygen, argon, nitrogen, freon, methane, ethane, propane, natural gas, coal gas or biogas; The N medium can also be other low temperature media. Preferably, the first medium is carbon dioxide or ammonia, the second medium is freon, and the third medium is nitrogen.

The waste heat recovery and utilization system in the embodiment passes through the N circulation loops through which the gas-liquid phase change medium flows, and the N-1 grade condenser causes the Nth medium flowing through the Nth circulation loop to cool the N-1 grade steam turbine or The N-1 medium output from the N-1 grade expander adopts a low temperature liquid medium (at a pressure of one atmosphere) whose boiling point temperature is lower than 0 degrees Celsius, so that each circulation loop completes isentropic compression and isobaric heating according to the Rankine cycle theory. Isentropic expansion, isobaric condensation; equal pressure condensation in the first-stage Rankine cycle in the low-temperature field by using a low-temperature medium lower than the boiling temperature of the previous medium (at one atmosphere), ie, the previous stage, etc. The pressure condensation is the isostatic heating process of the latter-stage Rankine cycle. Under certain conditions, the latent heat of evaporation in the previous Rankine cycle can be fully converted into the rotary mechanical energy output of the steam turbine or expander; In theory, the efficiency of converting the residual heat of the residual heat exchanger 101 into the rotational mechanical energy of the residual heat exchanger 101 in the waste heat recovery system can be significantly improved, thereby effectively utilizing the residual heat exchanger 101 to some extent. The latent heat energy, waste heat to avoid wasting a lot of latent heat energy.

In an alternative embodiment of the present invention, the waste heat recovery utilization system includes a refrigeration cycle in which a gas-liquid phase change medium flows, and a N-th medium that is cooled by an N-stage steam turbine or an N-stage expander through a refrigeration cycle.

Specifically, the refrigeration cycle includes an N-stage condenser, a compressor 401, a heat exchanger 402, and an expansion valve 405 that are sequentially connected in series. That is, the N-stage condenser, the compressor 401, the heat exchanger 402, and the expansion valve 405 are sequentially connected end to end to form a refrigeration cycle.

The N-stage condenser is used to cool the N-stage medium output from the N-stage turbine or the N-stage expander by the refrigerant flowing through the refrigeration cycle.

The compressor 401 is used to compress the refrigerant, and the refrigerant is cooled and sent to the expansion valve 405 through the heat exchanger 402. Optionally, the expansion valve 405 herein can also be replaced by a refrigeration expander. The refrigerant flows through the compressor 401 to generate a high pressure, is input to the input end of the refrigeration expander through the condenser 402, and the refrigerant passes through the refrigeration expander. The latter is a semi-vacuum low pressure state, where the refrigeration expander is a differential pressure power generation for recovering the pressure energy generated by the compressor.

Optionally, the refrigerant medium of the refrigeration cycle is a cryogenic liquid medium having a boiling point below 0 degrees Celsius. Optionally, the boiling point of the refrigerant medium is not higher than the boiling point of the Nth medium, so that the refrigerant medium cools the Nth medium in the N-stage condenser. Optionally, the refrigerant medium is an inorganic low temperature medium or an organic low temperature medium. Optionally, the boiling point of the refrigerant medium is below -30 °C. The refrigerant medium may be, for example, carbon dioxide, ammonia, helium, hydrogen, oxygen, argon, nitrogen, freon, methane, ethane, propane, natural gas, coal gas or biogas; of course, the refrigerant medium may also be other low temperature medium. Preferably, the refrigerant medium is nitrogen or a medium having a lower boiling point than nitrogen.

Optionally, the refrigerant medium of the refrigeration cycle is a gas-liquid phase change medium, that is, the refrigerant medium performs gas phase and liquid phase conversion in the refrigeration cycle.

In an alternative embodiment of the present embodiment, the heat exchanger 402 is disposed between the N-stage liquid pump and the N-1 stage condenser; after the compressor 401 compresses the refrigerant medium, the refrigerant medium is heated, and the N-th cycle is passed through the heat exchanger 402. The Nth medium of the loop exchanges heat with the refrigerant medium of the refrigeration cycle, and after heating the Nth medium through the heat exchanger 402, the heat energy generated by compressing the refrigerant medium through the compressor 401 can be effectively utilized, thereby improving the energy utilization rate of the system. , reducing the loss of energy.

Optionally, a heat exchange exhaust valve 501 for exhaust gas is disposed on the pipeline between the heat exchanger 402 and the N-1 stage condenser. The pressure on the line between the heat exchanger 402 and the N-1 stage condenser can be released through the heat exchange exhaust valve 501.

Optionally, a compressed inlet liquid separator 407 is connected between the N-stage condenser and the compressor 401; the compressed inlet liquid separator 407 is configured to separate the refrigerant medium of the refrigeration cycle, and deliver the refrigerant medium in the gas phase to the compressor 401; by compressing the inlet liquid separator 407 to ensure that the refrigerant delivered to the compressor 401 is a gas, thereby increasing the service life of the compressor 401.

Optionally, a cooling cryogenic refrigerant storage medium is connected between the expansion valve 405 and the heat exchanger 402 to store the refrigerant medium through the refrigeration low temperature working fluid storage, and to improve the stability performance of the refrigeration cycle. Among them, the refrigeration low temperature working medium memory is used for storing the refrigerant medium, and the stability performance of the refrigeration cycle can be improved to some extent.

Optionally, a refrigerating liquid separator is connected between the heat exchanger 402 and the refrigerating cryogenic working fluid; the refrigerating liquid separator is used for separating the refrigerating medium of the refrigerating circuit, and the cooling medium in the liquid phase is sent to the refrigerating cryogenic working medium. The refrigerant is passed through the refrigerating liquid separator to ensure that the refrigerant medium delivered to the refrigerating cryogenic refrigerant storage medium is liquid, to some extent reduce or avoid the refrigeration of the low temperature working medium reservoir to withstand pressure or withstand a large pressure to improve the refrigeration low temperature working medium The security of the memory.

Optionally, a refrigerating storage inlet valve is disposed between the refrigerating cryogenic refrigerant and the refrigerating liquid separator; and a refrigerating storage outlet valve is disposed between the expansion valve 405 and the refrigerating cryogenic refrigerant. Through the refrigeration memory inlet valve and the refrigeration storage outlet valve, the refrigeration low temperature working fluid storage can constitute an independent low temperature working fluid storage device, and can also be combined with the refrigeration medium in the N-stage condenser of the refrigeration cycle circuit, the compressor 401 and the like. Circulate and separate to operate the protection and control system under specific conditions.

In an alternative embodiment of the present embodiment, the waste heat recovery system includes a cooling in-line line; and the N-stage medium output by the N-stage steam turbine or the N-stage expander is cooled by cooling the straight-discharge line.

Specifically, the cooling in-line pipeline includes a cooling in-line cryogenic working fluid 408, a cooling in-line liquid pump 409, an N-stage condenser, and a cooling in-line output terminal that are sequentially connected; alternatively, the cooling in-line output The end is provided with a cooling in-line valve 410. Optionally, a cooling storage outlet valve 4081 is disposed between the cooling in-line cryogenic working fluid storage 408 and the cooling in-line liquid pump 409; and the cooling in-line cryogenic working reservoir 408 and the cooling in-line liquid are controlled by cooling the storage outlet valve 4081 The circuit between the pumps 409 is turned on and off.

The cooling in-line liquid pump 409 is configured to supply the cooled in-line medium in the cooled in-line cryogenic working fluid storage 408 to the N-stage condenser, and is discharged through the cooling straight-discharge output end, or can be said to be discharged through the cooling in-line valve 410. For example, the cooling in-line valve 410 is opened, and the cooled in-line medium is discharged through the cooling straight discharge end. The Nth cycle can be normally operated by cooling the in-line medium in the N-stage condenser to cool the Nth stage of the N-stage turbine or the N-stage expander output.

Optionally, the cooled in-line medium that cools the in-line line is a cryogenic liquid medium having a boiling point below 0 degrees Celsius. Optionally, the boiling straight-line medium has a boiling point no higher than the boiling point of the N-th medium to facilitate cooling the in-line medium to cool the N-th medium in the N-stage condenser. Optionally, the cooling in-line medium is an inorganic low temperature medium or an organic low temperature medium. Optionally, the cooled inline medium has a boiling point below -30 °C. Wherein, the cooling straight discharge medium may be, for example, carbon dioxide, ammonia, helium, hydrogen, oxygen, argon, nitrogen, freon, methane, ethane, propane, natural gas, coal gas or biogas; of course, the cooling straight medium may also be other low temperature. medium. Preferably, the cooled in-line medium is nitrogen or a medium having a boiling point lower than nitrogen.

Optionally, the cooling in-line medium is a non-combustible medium, such as carbon dioxide, ammonia, helium, hydrogen, oxygen, argon, nitrogen, freon, etc., and the direct discharged medium is directly discharged. Optionally, the cooling straight-discharge medium is a combustible medium; for example, the cooling straight-discharge medium is methane, ethane, propane, oxygen, natural gas, coal gas or biogas, etc. Further, the cooling straight discharge output is connected to the combustion chamber of the boiler, The cooling straight discharge medium discharged from the cooling straight discharge pipe is burned in the boiler to fully utilize the cooling straight discharge medium, thereby avoiding or reducing the waste of cooling the straight discharge medium.

Optionally, the cooling straight-discharge medium for cooling the straight-line pipeline is a gas-liquid phase-change medium, that is, the cooling straight-discharge medium is subjected to gas phase and liquid phase conversion in the cooling straight-line pipeline. Optionally, the cooling in-line medium is completely or partially in a liquid state in the cooling in-line cryogenic working fluid 408, and the cooling in-line medium flows through the expansion valve 405 to release the pressure.

In this embodiment, as shown in FIG. 3, in the first circulation loop, a first-stage auxiliary heat exchanger may be disposed between the residual heat exchanger and the first-stage steam turbine or the first-stage expander; when N is an integer greater than or equal to 2, In the N cycle, an N-stage auxiliary heat exchanger is disposed between the N-1 stage condenser and the N-stage steam turbine or the N-stage expander. The auxiliary heat exchanger can heat the working fluid in the corresponding cycle, increase the input temperature and energy of the cycle, and thereby improve the power generation efficiency of the circulation circuit. Specifically, the natural gas can be selected for cooling the straight discharge medium, and the natural gas discharged through the cooled direct discharge valve 410 after being heated can be sent to the auxiliary heat exchanger for combustion in the corresponding cycle, wherein the heat generated by burning 1 kg of natural gas is 50009 kJ, energy. It is much larger than the vaporization endothermic energy of natural gas (1kg natural gas gasification endothermic 508kJ), thus improving the power generation efficiency of the generator.

The waste heat power generation system can also be a highly efficient power unit. For example, the primary cycle is preferably water and steam, the secondary cycle is preferably carbon dioxide, the CO2 is condensed and the latent heat of steam is absorbed, and the tertiary cycle is preferably an R50 refrigerant (LNG liquid) of minus -160 degrees Celsius, preferably minus -160 ° C. The R50 refrigerant absorbs the latent heat of CO2 circulating waste steam, and the carbon dioxide cycle of -60 °C is condensed below -160 °C; the final cooling medium is liquefied natural gas LNG (1 kg natural gas gasification endothermic 508 kJ), the third stage R50 refrigerant (LNG liquid) power generation cycle, set as a back pressure steam turbine with a certain exhaust pressure, the condensation temperature is set at 140 ° C -150 ° C; the final cooling straight discharge medium through the tertiary condenser 303 heat absorption gasification, cooling straight The valve 410 is discharged, the natural gas can be sent to the auxiliary heat exchanger for combustion, the first cycle of water is heated, the temperature is raised, and the first cycle efficiency is achieved to reach 30% or more; and then a part of the natural gas is sent to the second stage of the auxiliary exchange. The heater burns, burns and raises the energy temperature of the carbon dioxide cycle, and strives to achieve a CO2 cycle efficiency of more than 30%; and then transports a portion of the natural gas to the third-stage cycle. The energy temperature of the R50 refrigerant cycle at the auxiliary heat exchanger for combustion, combustion and hoisting, so that the R50 refrigerant cycle efficiency can also reach nearly 30%.

The efficiency of the first steam power generation cycle is about 30%, and the latent heat of spent steam is absorbed by the CO2 power generation cycle of the second stage -56 degrees Celsius, and the efficiency of the carbon dioxide power generation cycle is enhanced by natural gas combustion, so that it can achieve about 30%; The R50 refrigerant at 160 °C absorbs the latent heat of carbon dioxide exhaust gas at minus -56 °C, and at the same time uses a small portion of natural gas to burn and heat the R50 refrigerant (R50 has oxygen, and the ignition point is around 630 °C, as a power generation, it is very Thick high-pressure metal, completely isolated from oxygen, and absolutely safe at around 100 °C); third-stage cycle efficiency strives to achieve efficiency of about 25-30%, so that the sum of the total cycle efficiency of the three cycles can reach 80% Above; 1kg of natural gas combustion produces 50009kJ of heat and 80% of power generation efficiency. It can be used as a power machine instead of the existing diesel engine and used in various ships. Previous ships were steam turbines. Because diesel engines can reach more than 40% efficiency, they replaced low-efficiency (20-30%) steam turbines. However, diesel engines are noisy, and it is difficult to process large diesel engines. Steam turbines are relatively simple in structure. It can be arbitrarily made large; therefore, the use of steam turbines will reduce the shipbuilding cost and manufacturing difficulty. The use of three-stage steam turbine structure and the use of spent steam latent heat power generation can significantly improve the energy efficiency of ship units. If more than 80% energy efficiency can be achieved, the future will It is widely used in power equipment and power plants such as ships; it contributes to national and global energy conservation and environmental protection.

In an alternative embodiment of the present embodiment, the waste heat recovery system includes a refrigeration cycle and/or a cooling straight line, that is, the waste heat recovery system includes a refrigeration cycle, or the waste heat recovery system includes a cooling straight line, or waste heat The recycling system includes a refrigeration cycle and a cooling straight line. Optionally, the waste heat recovery system includes a refrigeration cycle or a cooling straight line to simplify the waste heat recovery system and reduce the construction cost of the system. In addition, the waste heat recovery system may also include other equipment, piping for cooling the Nth medium of the N-stage turbine or the N-stage expander output. The system is preferred, and the cooling inline line is used in conjunction with a refrigeration cycle (heat pump system).

In an alternative embodiment of the present invention, when N is an integer greater than or equal to 1, an N-stage cryogenic working memory is disposed between the N-stage condenser and the N-stage liquid pump; wherein the N-stage cryogenic working memory is used for storing the first N medium can improve the stability of the Nth loop to a certain extent. For example, when N is 1, for example, a primary cryogenic working memory 106 is disposed between the primary condenser 103 and the primary liquid pump 107; wherein the primary cryogenic refrigerant 106 is used to store the first medium, which may be to some extent Improve the stability of the first loop. Optionally, the N-stage cryogenic refrigerant storage jacket has an insulating layer.

Optionally, when N is an integer greater than or equal to 1, an N-stage condensing pump is connected between the N-stage condenser and the N-stage cryogenic refrigerant storage; and the N-stage condensing pump is used to make the N-th medium flowing through the N-stage condenser It is input into the N-stage cryogenic working memory; the N-stage condensing pump is used to deliver the N-th medium flowing through the N-stage condenser to the N-stage cryogenic working memory. For example, when N is 1, a primary condensing pump 105 is connected between the primary condenser 103 and the primary cryogenic refrigerant reservoir 106; the primary condensing pump 105 is configured to input the first medium flowing through the primary condenser 103 to the first medium. The first low temperature working fluid reservoir 106 is passed through the primary condensate pump 105 to deliver the first medium flowing through the primary condenser 103 to the primary cryogenic refrigerant storage 106. Optionally, the N-stage condensate pump jacket has an insulating layer.

Optionally, when N is an integer greater than or equal to 1, an N-stage liquid separator is connected between the N-stage condenser and the N-stage condensate pump; the N-stage liquid separator is used to separate the N-th medium of the N-th recycle loop, and The Nth medium in the liquid phase is sent to the N-stage condensate pump; the N-stage liquid separator is passed through to ensure that the N-th medium delivered to the N-stage cryogenic working medium through the N-stage condensing pump is liquid, which is reduced or avoided to some extent. Class N cryogenic refrigerants are subjected to pressure or subjected to large pressures to improve the safety of Class N cryogenic refrigerants. For example, when N is 1, a primary liquid separator 104 is connected between the primary condenser 103 and the primary condensing pump 105; the primary liquid separator 104 is used to separate the first medium of the first circulation circuit, and is in a liquid phase. The first medium is delivered to the primary condensate pump 105; through the primary liquid separator 104 to ensure that the first medium delivered to the primary cryogenic refrigerant reservoir 106 via the primary condensate pump 105 is a liquid. Optionally, the N-stage liquid separator is jacketed with an insulating layer.

Optionally, when N is an integer greater than or equal to 1, an N-stage memory inlet valve is disposed between the N-stage condensate pump and the N-stage cryogenic working memory; and the N-stage liquid pump and the N-stage cryogenic working memory are disposed with N Stage memory outlet valve; through the N-stage memory inlet valve and the N-stage memory outlet valve, so that the N-stage cryogenic refrigerant storage can constitute an independent cryogenic working storage device, and can also be combined with the N-stage condenser of the Nth loop circuit, The Nth medium in equipment such as Class N liquid pumps is circulated and separated to operate the protection and control system under specific conditions. For example, when N is 1, a primary storage inlet valve 1061 is disposed between the primary condensate pump 105 and the primary cryogenic refrigerant reservoir 106; a primary storage outlet valve is disposed between the primary liquid pump 107 and the primary cryogenic refrigerant reservoir 106. 1062; through the primary storage inlet valve 1061 and the primary storage outlet valve 1062, so that the primary cryogenic refrigerant reservoir 106 can constitute a separate cryogenic working storage device, and can also be coupled to the primary condenser 103 of the first circulation loop. The first medium in the first stage liquid pump 107 and the like is circulated and separated to operate the protection and control system under certain circumstances.

Optionally, when N is an integer greater than or equal to 1, the N-stage cryogenic refrigerant memory is provided with an N-stage memory compensation exhaust valve; and the N-stage memory compensation exhaust valve is used to compensate or discharge the medium in the N-stage cryogenic refrigerant memory. The medium may be the Nth medium in the N-stage low temperature working medium memory, or may be the other medium such as air in the N-stage low temperature working memory for the first time; the exhaust valve is compensated by the N-level memory to be able to supplement the N-stage. The Nth medium of the low temperature working medium memory compensates for the Nth medium leaking and volatilizing in the Nth circulating circuit; the N-stage memory compensates the exhaust valve, and can also discharge the Nth medium which is gas in the N-stage low temperature working memory, To a certain extent, reduce or avoid the pressure of the N-stage cryogenic refrigerant storage or withstand a large pressure to improve the safety performance of the N-class cryogenic refrigerant storage. For example, when N is 1, the first-stage cryogenic working memory 106 is provided with a first-stage memory compensation exhaust valve 1063; the first-stage memory compensating exhaust valve 1063 is used to compensate or discharge the first medium in the first-stage cryogenic working memory 106; The primary storage compensates the exhaust valve 1063 to be able to supplement the first medium of the primary cryogenic refrigerant reservoir 106 to compensate for leakage and volatilization of the first medium in the first circulation loop; and to compensate the exhaust valve 1063 through the primary storage, A first medium that is a gas in the primary cryogenic refrigerant reservoir 106 is discharged.

Optionally, when N is an integer greater than or equal to 1, the N-stage condenser is provided with an N-stage condensing compensation exhaust valve; the N-stage condensing compensation exhaust valve is used for compensating or discharging the medium in the N-stage condenser, the medium may For the Nth medium in the N-stage condenser, it is also possible to first evacuate other medium such as air in the N-stage condenser. The N-stage condensing compensation exhaust valve is used to supplement the Nth medium of the N-stage condenser to compensate for the Nth medium leaking and volatilizing in the Nth circulation loop; and the N-stage condensation can be discharged through the N-stage condensing compensation exhaust valve. The Nth medium in the gas can reduce or prevent the N-stage condenser from being subjected to a large pressure to improve the safety performance of the N-stage condenser. For example, when N is 1, the primary condenser 103 is provided with a first-stage condensation compensation exhaust valve 1031; the first-stage condensation compensation exhaust valve 1031 is used to compensate or discharge the medium in the primary condenser 103, which may be a first-stage condensation The first medium in the device 103 may also be another medium such as air in the first-stage condenser 103 for the first time; the first medium of the primary condenser 103 may be supplemented by the first-stage condensation compensation exhaust valve 1031, Compensating for the first medium leaking and volatilizing in the first circulation loop; and through the first-stage condensation compensation exhaust valve 1031, the first medium or other impurities in the first-stage condenser 103 can be discharged, which can reduce or avoid a certain degree to a certain extent. The stage condenser 103 is subjected to a relatively large pressure to improve the safety performance of the primary condenser 103.

Alternatively, when N is an integer greater than or equal to 1, the N-stage steam turbine and the N-stage condenser are integrated devices, or the N-stage expander and the N-stage condenser are integrated devices to simplify the system structure and reduce the system cost. For example, when N is 1, the primary steam turbine and the primary condenser are integrated devices, or the primary expander and the primary condenser are integrated devices.

Optionally, when N is an integer greater than or equal to 1, the Nth circulation loop is provided with one or more circulation loop discharge valves 502, and the circulation loop discharge valve 502 is used for discharging the medium in the Nth circulation loop; the medium may be N grade The Nth medium in the condenser may also be other medium such as air in the N-stage condenser for the first time. Optionally, a circulation loop discharge valve 502 is provided at the output or input of the N-stage condenser; alternatively, the circulation loop discharge valve 502 is disposed at the output or input of the N-stage or N-stage expander. As shown in FIGS. 1-3, a circulation loop discharge valve 502 is provided in the first circulation circuit between the primary liquid pump 107 and the primary cryogenic refrigerant reservoir 106.

Optionally, the N-stage steam turbine or the N-stage expander, the N-stage condenser, and the N-stage liquid pump are jacketed with an insulation layer.

Referring to Figures 1-3, the waste heat recovery system shown in the figure includes three circulation loops through which a gas-liquid phase change medium flows.

Specifically, the first circulation loop includes a residual heat exchanger 101 that is connected in series from end to end, a primary steam turbine 102 or a primary expander, a primary condenser 103, a primary liquid separator 104, a primary condensing pump 105, and a primary storage. An inlet valve 1061, a primary cryogenic refrigerant reservoir 106, a primary storage outlet valve 1062, and a primary liquid pump 107; wherein the primary turbine 102 or the primary expander is coupled to the primary generator 108.

The second circulation loop includes a primary condenser 103, a secondary steam turbine 202 or a secondary expander, a secondary condenser 203, a secondary liquid separator 204, a secondary condensing pump 205, and a secondary storage inlet valve 2061. The secondary low temperature working fluid storage 206, the secondary storage outlet valve 2062 and the secondary liquid pump 207; wherein the secondary steam turbine 202 or the secondary expander is driven to connect the secondary generator 208.

The third circulation loop includes a secondary condenser 203, a three-stage steam turbine 302 or a three-stage expander, a three-stage condenser 303, a three-stage liquid separator 304, a three-stage condensing pump 305, and a three-stage memory inlet valve 3061 which are sequentially connected end to end. The third-stage low temperature working fluid storage 306, the tertiary storage outlet valve 3062 and the tertiary liquid pump 307; wherein the tertiary steam turbine 302 or the tertiary expander is driven to connect the tertiary generator 308.

When the waste heat recovery system includes a refrigeration cycle, the refrigeration cycle includes a three-stage condenser 303 that is connected in series from end to end, a compressed inlet liquid separator 407, a compressor 401, a heat exchanger 402, a refrigerant liquid separator, and a refrigeration storage inlet. Valve, refrigeration cryogenic refrigerant storage, refrigeration storage outlet valve and expansion valve 405.

When the waste heat recovery system includes cooling the straight discharge pipeline, the cooling straight discharge pipeline includes a cooling straight discharge cryogenic refrigerant storage 408, a cooling straight liquid pump 409, a tertiary condenser 303, and a cooling straight discharge valve 410 which are sequentially connected. .

In an alternative of this embodiment, the waste heat recovery system includes two circulation loops through which a gas-liquid phase change medium flows.

Specifically, the first circulation loop includes a residual heat exchanger 101 that is connected in series from end to end, a primary steam turbine 102 or a primary expander, a primary condenser 103, a primary liquid separator 104, a primary condensing pump 105, and a primary storage. An inlet valve 1061, a primary cryogenic refrigerant reservoir 106, a primary storage outlet valve 1062, and a primary liquid pump 107; wherein the primary turbine 102 or the primary expander is coupled to the primary generator 108.

The second circulation loop includes a primary condenser 103, a secondary steam turbine 202 or a secondary expander, a secondary condenser 203, a secondary liquid separator 204, a secondary condensing pump 205, and a secondary storage inlet valve 2061. The secondary low temperature working fluid storage 206, the secondary storage outlet valve 2062 and the secondary liquid pump 207; wherein the secondary steam turbine 202 or the secondary expander is driven to connect the secondary generator 208.

When the waste heat recovery system includes a refrigeration cycle, the refrigeration cycle includes a secondary condenser 203 that is connected in series from end to end, a compressed inlet liquid separator 407, a compressor 401, a heat exchanger 402, a refrigerant liquid separator 403, and a refrigeration memory. An inlet valve 4041, a refrigerated cryogenic refrigerant reservoir 404, a refrigerated storage outlet valve 4042, and an expansion valve 405.

When the waste heat recovery system includes cooling the straight discharge pipeline, the cooling straight discharge pipeline includes a cooling straight discharge cryogenic refrigerant storage 408, a cooling straight liquid pump 409, a secondary condenser 203, and a cooling straight discharge valve 410 which are sequentially connected. .

Optionally, the residual heat exchanger 101 is a boiler, and the cooling straight discharge output end of the cooling straight discharge pipeline communicates with the combustion chamber of the boiler, so that the cooled straight discharge medium discharged from the cooling straight discharge pipeline is burned in the boiler to fully utilize Cool the straight discharge medium to avoid or reduce the waste of cooling the straight discharge medium. Optionally, the first medium is water, the first medium is carbon dioxide, and the cooled straight medium may be, for example, a combustible medium such as methane, ethane, propane, oxygen, natural gas, coal gas or biogas.

It should be noted that carbon dioxide is a greenhouse gas, and a large number of glaciers in the Antarctic Arctic are constantly melting and global warming. Once used, the waste heat recovery system is likely to use a large amount of carbon dioxide liquid, which is equivalent to a kind of storage of greenhouse gases. The amount of such storage may be very large, and it can be said that it is also a huge contribution to our ecological environment and climate warming. .

The embodiment further provides a waste heat recovery and utilization method, which is applicable to the waste heat recovery and utilization system, and includes the following steps:

At a pressure of one atmosphere, the first medium in a liquid state having a boiling point temperature higher or lower than 0 ° C is transported from the first-stage low temperature working medium storage to the residual heat exchanger; the residual heat exchanger includes an air sea water heat exchanger and a waste heat condenser One or more of equipment cooling system waste heat recovery device, hot water waste liquid high temperature flue gas residual heat exchanger and boiler;

For example, in the residual heat exchanger, the temperature of the high temperature to-be-cooled material having a temperature of 30 ° C to 800 ° C is lowered to 5 ° C to 30 ° C after heat exchange with the first medium, and the temperature of the first medium is increased to 2 ° C after the endothermic vaporization. 10 ° C, the pressure rises above 1.5 MPa and is sent to the first stage turbine or the first stage expander;

After the first medium drives the first-stage steam turbine or the first-stage expander to rotate work, the temperature falls below -35 ° C, the pressure drops below 0.1 MPa and is sent to the primary condenser;

The first medium is cooled to below -50 ° C in the primary condenser, and is separated by a primary liquid separator and the first medium in the liquid phase is sent to the first-stage cryogenic working storage through the primary condensing pump. A first circulation loop is formed.

Optionally, the second medium in liquid state at a temperature below -50 ° C is transported from the secondary cryogenic refrigerant storage to the primary condenser;

In the first-stage condenser, the temperature of the first medium and the second medium of the first-stage steam turbine or the first-stage expander having a temperature of -20 ° C or less is lower than -50 ° C after heat exchange, and the second medium absorbs heat and vaporizes. After the temperature rises above -70 ° C, the pressure rises above 1.5 MPa and is sent to the secondary steam turbine or the secondary expander;

After the second medium drives the secondary steam turbine or the secondary expander to rotate, the temperature drops below about -90 ° C, the pressure drops below about 0.1 MPa, and is delivered to the secondary condenser;

The second medium is cooled in the secondary condenser to a temperature below about -100 ° C, separated by a secondary liquid separator, and the second medium in the liquid phase is transported to the secondary cryogenic working medium through the secondary condensing pump Forming a second circulation loop.

Optionally, the liquid medium having a temperature lower than -150 ° C is transported from the tertiary low temperature working medium reservoir to the secondary condenser;

In the secondary condenser, the temperature of the second medium of the output of the secondary steam turbine or the secondary expander below -90 ° C is reduced to -100 ° C after heat exchange with the third medium, while the third medium is vaporized by heat. The temperature is raised to -115 ° C, the pressure is raised to 1.5 MPa or more and sent to a three-stage steam turbine or a three-stage expander;

After the third medium drives the three-stage steam turbine or the third-stage expander to rotate work, the temperature drops below about -140 ° C, the pressure drops below about 0.1 MPa, and is sent to the third-stage condenser;

The third medium is cooled to a temperature below about -150 ° C in the tertiary condenser, separated by a three-stage liquid separator, and the third medium in the liquid phase is sent to the tertiary cryogenic refrigerant through a tertiary condensing pump. Forming a third circulation loop.

Optionally, the tertiary condenser of the third circulation loop is cooled by the refrigeration cycle or the cooled straight discharge line.

The refrigeration cycle includes a three-stage condenser that is connected in series from the beginning to the end, a compressed inlet liquid separator, a compressor, a heat exchanger, a refrigerant liquid separator, a refrigeration memory inlet valve, a refrigeration low temperature working fluid storage, a refrigeration storage outlet valve, and refrigeration. Expander or expansion valve.

The compressor compresses the refrigerant, and the refrigerant medium cooled by the heat exchanger is completely or partially liquid and the temperature drops below about -20 ° C, the pressure is about 1 Mpa and above, and is sent to the refrigeration low temperature working medium through the refrigerant liquid separator. Inside;

a refrigerant medium having a temperature of less than about -20 ° C, which is wholly or partially liquid, is transported from a refrigerated cryogenic refrigerant reservoir to a refrigeration expander or expansion valve;

After the refrigeration medium drives the refrigeration expander to rotate, the temperature drops to below about -50 ° C, the pressure drops below 0.1 MPa, and is sent to the tertiary condenser through the compressed inlet liquid separator;

In the third-stage condenser, the third medium of the output of the three-stage steam turbine or the three-stage expander having a temperature of -50 ° C or less and the temperature of the refrigerant medium are cooled to below -50 ° C, and the refrigerant medium absorbs all of the heat or The partial vaporization temperature rises by about 5 ° C to 10 ° C, the pressure rises to about 0.2 MPa, and is sent to the compressor to form a cycle.

The cooling straight discharge pipeline comprises a cooling straight-line cryogenic working fluid, a cooling straight liquid pump, a three-stage condenser and a cooling straight-discharge valve which are sequentially connected;

The third medium temperature after cooling the straight-line cryogenic working medium output and cooling the straight-line medium having a temperature of -50 ° C or less in the third-stage condenser and the third medium of the output of the third-stage steam turbine or the third-stage expander Decrease to below -50 °C, while cooling the in-line medium to absorb heat, the entire vaporization temperature rises to 5 °C-20 °C, the pressure rises to about 0.4MPa and is cooled or discharged to the output or cooled through the straight discharge valve.

The embodiment provides a power station. The embodiment includes the above-mentioned waste heat recovery and utilization system. The technical features of the waste heat recovery and utilization system are also applicable to the power station, and the technical features of the waste heat recovery and utilization system are not repeatedly described.

The power station provided in this embodiment includes a waste heat recovery and utilization system. Specifically, the power station may include multiple waste heat recovery and utilization systems.

The power station in this embodiment has the advantages of the above-described waste heat recovery and utilization system, and the advantages of the waste heat recovery and utilization system are not repeatedly described herein.

Finally, it should be noted that the above embodiments are only for explaining the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present application. range.

Industrial applicability

The waste heat recovery and utilization system and the method thereof and the power station provided by the embodiment can significantly improve the efficiency of converting the residual heat of the residual heat exchanger into the rotational mechanical energy of the residual heat exchanger in the waste heat recovery and utilization system through a plurality of circulation loops, thereby being effective to some extent. The latent heat energy of the residual heat in the residual heat exchanger is utilized, and the latent heat energy of the waste heat is reduced.

Claims (16)

1. A waste heat recovery utilization system, characterized in that the system comprises N circulation loops through which a gas-liquid phase change medium flows; wherein N is an integer greater than or equal to 1;

   When N is 1, the first circulation circuit includes a residual heat exchanger that is connected in series from the beginning to the end, a first-stage steam turbine or a first-stage expander, a first-stage condenser, and a first-stage liquid pump;

   When N is an integer greater than or equal to 2, the Nth cycle includes an N-1 stage condenser, an N-stage turbine or an N-stage expander, an N-stage condenser, and an N-stage liquid pump that are sequentially connected end to end; The condenser is configured to cool the N-1 medium outputted by the N-1 stage steam turbine or the N-1 stage expander through the Nth medium flowing through the Nth circulation loop;

   The N-stage condenser is configured to cool an N-th medium outputted by an N-stage steam turbine or an N-stage expander;

   The first medium of the first circulation loop is a cryogenic liquid medium; the Nth medium is a cryogenic liquid medium having a boiling point below 0 degrees Celsius at a standard atmospheric pressure.
2. The waste heat recovery and utilization system according to claim 1, wherein when N is an integer of 2 or more, the flow of the cryogenic liquid medium in the adjacent circulation circuit is reversed.
3. The waste heat recovery and utilization system according to claim 1 or 2, wherein the waste heat recovery and utilization system comprises three circulation loops, which are a first circulation loop, a second circulation loop, and a third circulation loop in sequence, the first loop The circuit includes a residual heat exchanger that is connected in series at the beginning and the end, a first-stage steam turbine or a first-stage expander, a first-stage condenser, and a first-stage liquid pump; and the second circulation circuit includes a first-stage condenser, a secondary steam turbine, or a secondary expansion that are sequentially connected in an end-to-end manner. The machine, the secondary condenser and the secondary liquid pump; the third circulation circuit comprises a secondary condenser, a three-stage steam turbine or a three-stage expander, a three-stage condenser and a three-stage liquid pump which are connected in series from the beginning to the end.
4. The waste heat recovery and utilization system according to any one of claims 1 to 3, characterized by comprising a refrigeration cycle through which a gas-liquid phase change medium flows;

   The refrigeration cycle includes the N-stage condenser, a compressor, a heat exchanger, and an expansion valve that are sequentially connected end to end;

   The N-stage condenser is configured to cause a refrigerant medium flowing through the refrigeration cycle to cool the N-th medium output by the expansion valve;

   The compressor is configured to compress a refrigerant medium and to cool the refrigerant medium through the heat exchanger to be delivered to the expansion valve.
5. The waste heat recovery utilization system according to claim 4, wherein said heat exchanger is disposed between said N-stage liquid pump and said N-1 stage condenser, and said heat exchanger is said a heat exchange exhaust valve configured as exhaust gas is disposed on the pipeline between the N-1 grade condensers;

   a compressed inlet liquid separator is connected between the N-stage condenser and the compressor; the compressed inlet liquid separator is configured to separate the refrigerant medium of the refrigeration cycle, and deliver the refrigerant medium in the gas phase to the Compressor

   a cooling and cryogenic working medium memory is connected between the expansion valve and the heat exchanger;

   a refrigerating liquid separator is connected between the heat exchanger and the refrigerating cryogenic working fluid; the refrigerating liquid separator is configured to separate the refrigerating medium of the refrigerating circuit, and deliver the refrigerant in a liquid phase to The refrigeration low temperature working fluid storage device;

   A refrigerating storage inlet valve is disposed between the refrigerating cryogenic refrigerant and the refrigerating liquid separator; and a refrigerating storage outlet valve is disposed between the expansion valve and the refrigerating cryogenic refrigerant.
6. The waste heat recovery utilization system according to any one of claims 1 to 5, characterized in that it comprises cooling a straight discharge line;

   The cooling straight-discharge line includes a cooling straight-line cryogenic working fluid sequentially connected, the N-stage condenser and a cooling straight-line output end;

   The N-stage condenser is configured to cool the N-stage medium outputted by the N-stage steam turbine or the N-stage expander by cooling the in-line medium in the cooled in-line cryogenic working medium, and deliver the same to the cooling straight The discharge output is discharged.
7. The waste heat recovery utilization system according to claim 6, wherein a cooling in-line liquid pump is disposed between the cooling in-line cryogenic refrigerant reservoir and the N-stage condenser, and the cooling in-line liquid pump configuration Cooling the straight-line medium in the cooled straight-line cryogenic working medium to the N-stage condenser;

   a cooling storage outlet valve is disposed between the cooled in-line cryogenic working fluid reservoir and the cooled in-line liquid pump;

   The cooling straight discharge output is provided with a cooling straight discharge valve.
8. The waste heat recovery utilization system according to claim 6, wherein the cooling in-line medium is a combustible medium;

   The cooled straight discharge output is in communication with a combustion chamber of the boiler.
9. The waste heat recovery and utilization system according to any one of claims 1-8, wherein the residual heat exchanger comprises an air seawater heat exchanger, a waste heat condenser, a device cooling system waste heat recovery device, and a hot water waste liquid high temperature. One or more of a flue gas heat exchanger and a boiler;

   When the residual heat exchanger includes an air seawater heat exchanger, the air seawater heat exchanger is provided with a deicing defrosting device and a fan device; the deicing defrosting device can provide the outer casing of the air seawater heat exchanger Heat, the fan device is configured to accelerate seawater or air flowing through the air seawater heat exchanger.
10. The waste heat recovery and utilization system according to any one of claims 1 to 9, wherein the residual heat exchanger comprises an air seawater heat exchanger, a waste heat condenser, a device cooling system waste heat recovery device, and a hot water waste liquid high temperature. The flue gas residual heat exchanger and the boiler, the air seawater heat exchanger, the waste heat condenser, the equipment cooling system waste heat recovery device, the hot water waste liquid high temperature flue gas residual heat exchanger and the boiler are connected in series or in parallel.
11. The waste heat recovery and utilization system according to claim 10, wherein the residual heat exchanger comprises a hot water waste liquid high temperature flue gas residual heat exchanger, and the hot water waste liquid high temperature flue gas residual heat exchanger is disposed in the flue.
12. The waste heat recovery and utilization system according to any one of claims 1 to 11, wherein when N is an integer greater than or equal to 1, the N-stage condenser and the N-stage liquid pump are disposed to be disposed. An N-stage cryogenic working memory for storing the Nth medium;

    An N-stage condensing pump is connected between the N-stage condenser and the N-stage cryogenic refrigerant reservoir; the N-stage condensing pump is configured to input an N-th medium flowing through the N-stage condenser to the N Level low temperature working fluid storage;

    An N-stage liquid separator is connected between the N-stage condenser and the N-stage condensate pump; the N-stage liquid separator is configured to separate the N-th medium of the N-th recycle loop, and is in a liquid phase The Nth medium is delivered to the N-stage condensate pump;

    An N-stage memory inlet valve is disposed between the N-stage condensate pump and the N-stage low temperature working fluid storage; an N-stage memory outlet valve is disposed between the N-stage liquid pump and the N-stage low temperature working fluid storage;

    The N-stage cryogenic refrigerant memory is provided with an N-stage memory compensation exhaust valve; the N-stage memory compensation exhaust valve is configured to compensate or discharge the medium in the N-stage cryogenic refrigerant memory;

    The N-stage condenser is provided with an N-stage condensation compensation exhaust valve; the N-stage condensation compensation exhaust valve is configured to compensate or discharge the medium in the N-stage condenser;

    The N-stage steam turbine and the N-stage condenser are integrated devices, or the N-stage expander and the N-stage condenser are integrated devices;

    The Nth circulation circuit is provided with one or more circulation circuit discharge valves, and the circulation circuit discharge valve is configured to discharge the medium in the Nth circulation circuit;

    The N-stage steam turbine or the N-stage expander, the N-stage condenser and the N-stage liquid pump are jacketed with an insulation layer;

    When N is an integer greater than or equal to 2, the boiling point of the Nth medium is not higher than the boiling point of the N-1 medium;

    The first medium is water, carbon dioxide, ammonia, helium, hydrogen, oxygen, argon, nitrogen, freon, methane, ethane, propane, natural gas, coal gas or biogas;

    When N is an integer greater than or equal to 2, the Nth medium is carbon dioxide, ammonia, helium, hydrogen, oxygen, argon, nitrogen, freon, methane, ethane, propane, natural gas, coal gas or biogas;

    When N is an integer greater than or equal to 1, the N-stage turbine or the N-stage expander is driven to connect an N-stage generator or a mechanical device.
13. The waste heat recovery utilization system according to claim 12, wherein when N is 1, a first stage is disposed between the residual heat exchanger and the first stage steam turbine or the first stage expander in the first circulation circuit. Auxiliary heat exchanger

    When N is an integer greater than or equal to 2, an N-stage auxiliary heat exchanger is disposed between the N-1 stage condenser and the N-stage steam turbine or the N-stage expander in the N-th circulation circuit.
14. The waste heat recovery utilization system according to claim 13, wherein said circulation circuit discharge valve is provided at an output end or an input end of the N-stage expansion valve.
15. A waste heat recovery and utilization method, applicable to the waste heat recovery and utilization system according to any one of claims 1 to 14, wherein the waste heat recovery and utilization system comprises three circulation loops, which are sequentially a first circulation loop, The second cycle and the third cycle, the process of waste heat recovery is as follows:

    The first medium in the first circulation loop is sent to the residual heat exchanger, and in the residual heat exchanger, the temperature of the high temperature to be cooled product at a temperature of 30 ° C to 800 ° C is cooled to 5 ° C - 30 ° C after heat exchange with the first medium. At the same time, after the first medium absorbs heat, the temperature rises to 2 ° C -10 ° C, the pressure rises to 1.5 MPa or more and is sent to the first-stage steam turbine or the first-stage expander; the first medium drives the first-stage steam turbine or the first-stage expander to rotate After that, the temperature drops below -35 ° C, the pressure drops below 0.1 MPa and is sent to the primary condenser; the first medium is cooled to below -50 ° C in the primary condenser and is separated by a primary liquid separator. And conveying the first medium in the liquid phase to the first-stage cryogenic working medium through the first-stage condensing pump to form a first circulation loop;

    In the second circulation loop, the second medium having a temperature lower than -50 ° C is sent to the first-stage condenser, and in the first-stage condenser, the output of the first-stage steam turbine or the first-stage expander having a temperature of -20 ° C or less After the medium is heat exchanged with the second medium, the temperature drops below -50 ° C, and the temperature of the second medium is increased to -70 ° C or higher, the pressure is raised to 1.5 MPa or more, and the pressure is raised to the secondary steam turbine or the secondary expander. After the second medium drives the secondary steam turbine or the secondary expander to rotate, the temperature drops below -90 ° C, the pressure drops below 0.1 MPa and is sent to the secondary condenser; the second medium is cooled in the secondary condenser The temperature is reduced to below -100 ° C, separated by a two-stage liquid separator and the second medium in a liquid phase is sent to the secondary cryogenic working medium through a secondary condensing pump to form a second circulation loop;

    In the third circulation loop, the third medium having a temperature lower than -150 ° C is transported from the tertiary low temperature working medium storage to the secondary condenser; in the secondary condenser, the second stage steam having a temperature below -90 ° C Or the second medium of the output of the secondary expander is cooled to -100 ° C after heat exchange with the third medium, and the temperature of the third medium is increased to -115 ° C after the endothermic vaporization, the pressure is raised to 1.5 MPa or more and transported to three a steam turbine or a three-stage expander; after the third medium drives the three-stage steam turbine or the third-stage expander to rotate, the temperature drops below -140 ° C, the pressure drops below about 0.1 MPa, and is sent to the third-stage condenser; In the third-stage condenser, the cooling temperature is reduced to below -150 ° C, and the third medium separated by the three-stage liquid separator is transported to the third-stage low-temperature working medium through the three-stage condensing pump to form a third medium. Loop circuit.
16. A power station comprising the waste heat recovery and utilization system according to any one of claims 1-14.

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