CN102022221B - Two-stage single-screw expander Organic Rankine Cycle Diesel Engine Exhaust Heat Utilization System - Google Patents

Abstract

The invention relates to an organic Rankine cycle diesel engine tail gas and waste heat utilization system using a two-stage single-screw expanding machine, belonging to the field of energy conservation and emission reduction, and mainly comprising a gas compressor, an engine, a turbomachine, a tube bundle type evaporator, a single-screw expanding machine I, a magnetic powder dynamometer I, a single-screw expanding machine II, a magnetic powder dynamometer II, a plate type condenser, a liquid storage tank, a working medium pump, an intermediate heater, a cooling tower, an adjustable flow pump, a flow divider valve I of an expanding machine outlet, a flow divider valve II of the expanding machine outlet, a flow divider valve III of the expanding machine outlet, an exhaust control valve I, an exhaust control valve II, a turbomachine and compressor coupling shaft, a coupling shaft I, a coupling shaft II and various connecting pipelines. According to the conditions of different rotating speeds and different loads of a diesel engine, by utilizing the invention, the opening and closing of the flow divider valves of the expanding machine outlet and the exhaust control valves are adjusted, waste heat recoveries at different levels are realized and the energy taken away by the tail gas of the diesel engine is furthest recovered and utilized.

Description

Two-stage single-screw expander Organic Rankine Cycle Diesel Engine Exhaust Heat Utilization System

technical field

The invention relates to a two-stage single-screw expander organic Rankine cycle diesel engine tail gas waste heat utilization system, which is mainly used for recycling the heat taken away by the tail gas of a vehicle diesel engine, and belongs to the field of energy saving and emission reduction.

Background technique

According to heat balance analysis, the heat converted into effective work in a diesel engine only accounts for 30%-45% of the heat emitted by fuel combustion, while 25%-45% of the total heat of fuel combustion is discharged with the exhaust gas. If some technical means are used to recover the heat taken away by the exhaust gas of the diesel engine, it can not only improve the comprehensive energy utilization rate of the diesel engine, but also have a significant fuel-saving effect.

At present, the methods of recovering the energy taken away by the exhaust gas of diesel engines mainly include exhaust gas turbocharging technology, thermoelectric power generation technology, engine waste heat heating and cooling technology, followed by steam power cycle technology, etc. However, these technologies currently have some shortcomings. The main disadvantage of exhaust gas turbocharging technology is that it can only use the kinetic energy of engine exhaust, and its heat energy is not used but lost; the main disadvantage of thermoelectric power generation technology is that it can only recover part of the heat energy of diesel engine exhaust due to the limitation of materials. , but cannot fully recover the heat taken away by the exhaust of the diesel engine; the disadvantage of engine waste heat heating and cooling is that the energy utilization rate is relatively low; the main disadvantage of the subsequent steam power cycle technology is that it is difficult to recover low-grade heat source energy. The work technology of the post-heated steam power cycle is mainly based on the principle of the classic Rankine cycle, that is, the steam power cycle system composed of evaporators, expanders, condensers, pumps and other main components works. The working fluid used in the classic Rankine cycle is water. Under normal pressure, steam will only appear when the temperature reaches 100°C. The design of the turbine requires that no liquid droplets appear in the turbine, so the evaporation temperature of the system is at 100°C. ℃ and above, the system can be guaranteed to be in a normal operating state; in addition, the latent heat of vaporization of water is very large compared with organic working fluids, and the heat that water needs to absorb when changing from a saturated liquid state to a saturated gas state is relatively higher than that of organic working fluids. The mass is very large, so the requirements for the heat source are relatively high, and the energy of the low-grade heat source cannot be absorbed; while the output power of the turbomachinery that can be seen on the market is tens of kilowatts or more, and the turbine is used as an expansion machine. In the Ken cycle, what is needed is a heat source with a large flow rate and a high temperature, but it is difficult to recover a heat source with a small flow rate and a low temperature.

Contents of the invention

The purpose of the present invention is to overcome the limitation that low-grade heat source energy cannot be recovered in the classical Rankine cycle, and propose a scheme using a two-stage single-screw expander organic Rankine cycle diesel engine exhaust heat utilization system to recover diesel engine exhaust Take away the heat. It can be realized that when the diesel engine is under the conditions of different speeds and different loads, without affecting the normal operation of the diesel engine, the recovery rate of the exhaust heat of the diesel engine can be greatly improved, thereby improving the fuel economy of the diesel engine and the comprehensive energy utilization of the diesel engine.

In order to achieve the above object, the present invention adopts the following measures:

The present invention uses organic matter as the working fluid of the Rankine cycle system. The evaporation temperature of this working fluid is generally relatively low under normal pressure, and its latent heat of vaporization is much lower than that of water, and it can be converted from a saturated liquid state to a saturated gas state after absorbing less heat. The Rankine cycle can absorb the energy of low-grade heat sources with small flow and low temperature, which is suitable for the characteristics of low exhaust temperature and small flow of vehicle diesel engines.

The invention adopts a two-stage single-screw expander as the expansion power machine of the organic Rankine cycle. This two-stage single-screw expander structure is suitable for the characteristics of the different energy carried away by the exhaust gas under the conditions of different speeds and different loads of the diesel engine. The single-screw expansion power machine is a volumetric expander that fills the gap in the world. Its principle is that when high-pressure gas or steam enters the single-screw expander, it converts thermal energy or pressure energy into mechanical energy through expansion, and drives the generator to generate electricity. This expander has good power output characteristics and temperature drop characteristics. Its power range is in the range of 1kW to 1000kW, which overcomes the shortcomings of traditional steam turbines and gas turbines that cannot be too small; its expansion ratio is in the range of 1 to 8. Can output more shaft work. In addition, the single-screw expander can use various types of working fluid, which can be high-pressure gas, superheated steam, saturated steam, vapor-liquid two-phase or hot liquid, so it is especially suitable for the recovery of waste heat from various waste gases. The invention adopts a two-stage single-screw expander, which can meet the characteristics of different heats taken away by the tail gas of the diesel engine under the conditions of different rotating speeds and different loads, and recover as much heat as possible from the tail gas of the diesel engine.

In order to achieve the above object, the present invention adopts a two-stage single-screw expander Organic Rankine Cycle Diesel Engine Exhaust Heat Utilization System to recover the exhaust heat of diesel engine exhaust, which is characterized in that it includes a compressor, an engine, a turbine, a tube-bundle evaporator, and a single-screw expander I. Magnetic powder dynamometer I, single screw expander II, magnetic powder dynamometer II, plate condenser, liquid storage tank, working medium pump, intermediate heater, cooling tower, adjustable flow pump, expander outlet diverter valve I , expander outlet diverter valve II, expander outlet diverter valve III, exhaust control valve I, exhaust control valve II, turbine compressor coupling shaft, coupling shaft I, coupling shaft II and various connecting pipelines; The connection relationship of the components is: compressor, engine, turbine, tube bundle evaporator and intermediate heater are connected in sequence to form the direction of gas flow in the intake and exhaust system of the diesel engine, tube bundle evaporator, single screw expander I, intermediate heater The single-screw expander II, the plate condenser, the liquid storage tank and the working medium pump are sequentially connected to form a closed loop of the Rankine cycle, in which the single-screw expander I and the magnetic powder dynamometer I are connected through the coupling shaft I to measure the output The shaft work of the single-screw expander II and the magnetic powder dynamometer II are connected through the coupling shaft II to measure the output shaft work. The plate condenser, the cooling tower and the adjustable flow pump are connected in sequence to form a closed loop to form a cooling system; the entire diesel engine The circulation control of the tail gas waste heat utilization system is adjusted through the diverter valve at the outlet of the expander and the exhaust control valve. The outlet diverter valve I is connected to the plate condenser, the second pipeline is connected to the single-screw expander II through the expander outlet diverter valve II, and the third pipeline is connected to the intermediate heater through the expander outlet diverter valve III; tube bundle type The exhaust gas outlet side of the evaporator is divided into two pipelines through a three-way pipe. One pipeline is connected to the intermediate heater through the exhaust control valve I and then connected to the exhaust pipe, and the other pipeline is connected to the exhaust pipe through the exhaust control valve II. Directly connected; In addition, the turbine and the compressor are connected as a whole through the turbine-compressor connecting shaft.

Description of drawings

Figure 1 is a schematic diagram of a two-stage single-screw expander organic Rankine cycle diesel engine exhaust waste heat utilization system;

Figure 2 is a flow diagram of the low-temperature circulation system when the diesel engine is at low speed and low load;

Figure 3 is a flow schematic diagram of the medium-temperature circulation system when the diesel engine is at medium-high speed and medium-high load;

Figure 4 is a flow diagram of the high-temperature circulation system when the diesel engine is running at high speed and under heavy load;

In the figure: 1-compressor; 2-engine; 3-turbine; 4-tube bundle evaporator; 5-single-screw expander I; 6-magnetic powder dynamometer I; 7-single-screw expander II; 8-magnetic powder Dynamometer II; 9-plate condenser; 10-liquid storage tank; 11-working medium pump; 12-intermediate heater; 13-cooling tower; 14-adjustable flow pump; 15-expander outlet diverter valve I; 16-Expander outlet diverter valve II; 17-Expander outlet diverter valve III; 18-Exhaust control valve I; 19-Exhaust control valve II; 20-Turbine compressor coupling shaft; 21-Coupling shaft I; 22- Coupling axis II.

Detailed ways

Based on the characteristics that the heat taken away by the exhaust gas of the diesel engine changes under the conditions of different speeds and different loads, the present invention mainly recovers the heat taken away by the exhaust gas of the diesel engine through three sets of circulation systems: low-temperature cycle recovery waste heat system; medium-temperature cycle recovery waste heat system ; High temperature recycling waste heat system.

The used two-stage single-screw expander organic Rankine cycle diesel exhaust waste heat utilization system in the present invention mainly includes compressor 1, engine 2, turbine 3, tube bundle evaporator 4, single-screw expander 15, magnetic powder dynamometer 1 6. Single-screw expander II 7. Magnetic powder dynamometer II 8. Plate condenser 9. Liquid storage tank 10. Working medium pump 11. Intermediate heater 12. Cooling tower 13. Adjustable flow pump 14. Expander outlet shunt Valve I 15, expander outlet diverter valve II 16, expander outlet diverter valve III 17, exhaust control valve I 18, exhaust control valve II 19, turbine compressor coupling shaft 20, coupling shaft I 21, coupling shaft II 22 and various A connecting pipeline. The connection relationship of various components inside the system is as follows: compressor 1, engine 2, turbine 3, tube-bundle evaporator 4 and intermediate heater 12 are connected in sequence to form the direction of gas flow in the intake and exhaust systems of the diesel engine. Tube-bundle evaporator 4, single-screw expander I 5, intermediate heater 12, single-screw expander II 7, plate condenser 9, liquid storage tank 10 and working medium pump 11 are connected in sequence to form a closed loop of the Rankine cycle. Among them, the single-screw expander I 5 and the magnetic powder dynamometer I 6 are connected through the coupling shaft I 21 to measure the output shaft work, and the single-screw expander II 7 and the magnetic powder dynamometer II 8 are connected through the coupling shaft II 22 to measure all The output shaft work, the plate condenser 9, the cooling tower 13 and the adjustable flow pump 14 are sequentially connected to form a closed loop. The cycle control of the whole system is adjusted through the diverter valve at the outlet of the expander and the exhaust control valve. The specific connection method is as follows: the outlet of the single-screw expander I 5 is divided into three pipelines through the pipeline, and the first pipeline passes through the outlet of the expander. The diverter valve I 15 is connected to the plate condenser 9, the second line is connected to the single-screw expander II 7 through the expander outlet diverter valve II 16, and the third line is connected to the intermediate heater through the expander outlet diverter valve III17 12. The exhaust gas outlet side of the tube bundle evaporator 4 is divided into two pipelines through a three-way pipe, one pipeline is connected to the intermediate heater 12 through the exhaust control valve I 18 and then connected to the exhaust pipe, and the other pipeline passes through the exhaust gas The control valve II 19 is directly connected to the exhaust pipe. In addition, the turbine 3 and the compressor 1 are connected into one body through a turbine-compressor connection shaft 20 . (As shown in Figure 1)

The specific work process or operation of the present invention is illustrated below in conjunction with the accompanying drawings when the diesel engine is in different working conditions.

When the diesel engine is in low-speed and low-load conditions, the system starts the low-temperature waste heat recovery cycle system.

First, the expander outlet diverter valve II 16, expander outlet diverter valve III 17, and exhaust control valve I 18 are closed through the electronic control system, and the expander outlet diverter valve I 15 and exhaust control valve II 19 are opened. The low-temperature circulation system is mainly composed of a tube bundle evaporator 4, a single-screw expander I 5, a plate condenser 9, a liquid storage tank 10, and a working medium pump 11, wherein the single-screw expander I 5 and the magnetic powder dynamometer I 6 are connected through The shafts I and 21 are connected to each other to measure the output shaft work, and the plate condenser 9, the cooling tower 13 and the adjustable flow pump 14 are connected in sequence to form a closed loop to form a cooling system. The specific working conditions are as follows: the air enters the engine 2 after being compressed by the compressor 1, and is discharged by the engine 2 after combustion and expansion in the cylinder, and the exhaust gas enters the turbine 3 to drive the turbine 3 to rotate to drive the compressor 1 to work. The high-temperature gas that comes out passes through the tube-bundle evaporator 4 to release heat and then is discharged into the atmosphere through the exhaust pipe. The organic matter absorbs the heat released by the exhaust gas of the diesel engine in the tube-bundle evaporator 4 and converts it into a gaseous state, and the generated gas pushes the single-screw expander I 5 to expand and do work. Depleted air, the exhausted air enters the plate condenser 9 to release heat at constant pressure and is cooled to liquid. After the liquid enters the liquid storage tank 10, it is pumped by the working medium pump 11 to the tube bundle evaporator 4 for a new round of circulation. (as shown in picture 2)

When the diesel engine is in medium-to-high-speed, medium-to-high-load conditions, the system starts the medium-temperature waste heat recovery cycle system.

First, the expander outlet diverter valve I 15, expander outlet diverter valve III 17, and exhaust control valve I18 are closed through the electronic control system, and the expander outlet diverter valve II 16 and exhaust control valve II 19 are opened. The medium-temperature circulation system is mainly composed of tube bundle evaporator 4, single-screw expander I 5, single-screw expander II 7, plate condenser 9, liquid storage tank 10, and working medium pump 11, among which single-screw expander I 5 and magnetic powder The dynamometer I 6 is connected through the coupling shaft I 21 to measure the output shaft work, the single screw expander II 7 and the magnetic powder dynamometer II 8 are connected through the coupling shaft II 22 to measure the output shaft work, and the plate condenser 9, The cooling tower 13 and the adjustable flow pump 14 are connected in sequence to form a closed loop to form a cooling system. The specific working conditions are as follows: the air enters the engine 2 after being compressed by the compressor 1, and is discharged by the engine 2 after combustion and expansion in the cylinder, and the exhaust gas enters the turbine 3 to drive the turbine 3 to rotate to drive the compressor 1 to work. The high-temperature gas that comes out passes through the tube-bundle evaporator 4 to release heat and then is discharged into the atmosphere through the exhaust pipe. The organic matter absorbs the heat released by the exhaust gas of the diesel engine in the tube-bundle evaporator 4 and converts it into a gaseous state. The gas pushes the single-screw expander 15 to expand and do work, and the temperature and pressure drop form exhaust gas. The exhaust gas at this time also has high energy and can be used. Continue to recover, so the exhaust gas needs to be connected to the single-screw expander II 7 to continue to expand and work. After the gas is further lowered in temperature and pressure, it enters the plate condenser 9 to release heat at a constant pressure and is cooled to liquid, and the liquid enters the liquid storage tank 10. Finally, it is pumped into the tube bundle evaporator 4 by the working medium pump 11 to perform a new round of circulation. (As shown in Figure 3)

When the diesel engine is under high-speed and high-load conditions, the system starts the high-temperature waste heat recovery cycle system.

First, the expander outlet diverter valve I 15, expander outlet diverter valve II 16, and exhaust control valve II 19 are closed through the electronic control system, and the expander outlet diverter valve III 17 and exhaust control valve I 18 are opened. The high-temperature circulation system is mainly composed of tube-bundle evaporator 4, single-screw expander I 5, intermediate heater 12, single-screw expander II 7, plate condenser 9, liquid storage tank 10, and working fluid pump 11, of which the single-screw expansion The output shaft work can be measured by connecting the machine I5 and the magnetic powder dynamometer I6 through the coupling shaft I 21, and the output shaft work can be measured by connecting the single screw expander II 7 and the magnetic powder dynamometer II 8 through the coupling shaft II 22. The condenser 9, the cooling tower 13 and the adjustable flow pump 14 are connected in sequence to form a closed circuit to form a cooling system. The specific working conditions are as follows: the air enters the engine 2 after being compressed by the compressor 1, and is discharged by the engine 2 after combustion and expansion in the cylinder, and the exhaust gas enters the turbine 3 to drive the turbine 3 to rotate to drive the compressor 1 to work. The high-temperature gas that comes out passes through the tube-bundle evaporator 4 to release heat, then enters the intermediate heater 12 to continue releasing heat, and then is directly discharged into the atmosphere through the exhaust pipe. This is because when the diesel engine is in a high-speed and high-load working condition, the energy of the exhaust gas is not fully recovered in the tube-bundle evaporator 4, and the intermediate heater 12 behind it can recover more energy of the exhaust gas. The organic matter absorbs the heat released by the exhaust gas of the diesel engine in the tube-bundle evaporator 4 and converts it into a gaseous state, and the generated gas pushes the single-screw expander 15 to expand and do work, and the gas is cooled and depressurized to form exhaust gas, which is further absorbed in the intermediate heater 12 The heat released by the exhaust gas of the diesel engine, the enthalpy value increases as the temperature rises, and the high-temperature exhaust gas enters the single-screw expander II 7 to continue to expand and perform work. After the gas is further lowered in temperature and pressure, it enters the plate condenser 9 and is cooled to Liquid, after the liquid enters the liquid storage tank 10, it is pumped to the tube bundle evaporator 4 by the working medium pump 11 to perform a new round of circulation. (As shown in Figure 4)

Claims (2)

1. Two-stage single-screw expander organic Rankine cycle diesel engine exhaust waste heat utilization system, characterized in that it includes a compressor (1), a diesel engine (2), a turbine (3), a tube-bundle evaporator (4), and a single-screw expansion Machine I (5), magnetic powder dynamometer I (6), single screw expander II (7), magnetic powder dynamometer II (8), plate condenser (9), liquid storage tank (10), working medium pump (11), intermediate heater (12), cooling tower (13), adjustable flow pump (14), expander outlet diverter valve I (15), expander outlet diverter valve II (16), expander outlet diverter valve III (17), exhaust control valve I (18), exhaust control valve II (19), turbine compressor coupling shaft (20), coupling shaft I (21), coupling shaft II (22) and various connecting pipes The connection relationship of each component inside the system is: compressor (1), diesel engine (2), turbine (3), tube-bundle evaporator (4) and intermediate heater (12) are connected in sequence to form the intake and exhaust of the diesel engine Direction of gas flow in the system, tube bundle evaporator (4), single screw expander I (5), intermediate heater (12), single screw expander II (7), plate condenser (9), liquid storage tank (10) is sequentially connected with the working medium pump (11) to form a closed loop of the Rankine cycle, wherein the single screw expander I (5) is connected with the magnetic powder dynamometer I (6) through the coupling shaft I (21) to measure the output shaft work, the single-screw expander II (7) is connected to the magnetic powder dynamometer II (8) through the coupling shaft II (22) to measure the output shaft work, the plate condenser (9), the cooling tower (13) and The adjustable flow pumps (14) are connected in turn to form a closed circuit to form a cooling system; the cycle control of the entire diesel engine exhaust waste heat utilization system is adjusted through the expander outlet diverter valve and the exhaust control valve. The specific connection method is: single screw expander I ( The outlet of 5) is divided into three pipelines through the pipeline, the first pipeline is connected to the plate condenser (9) through the expander outlet diverter valve I (15), and the second pipeline is connected to the plate condenser (9) through the expander outlet diverter valve II ( 16) Connected to the single-screw expander II (7), the third pipeline is connected to the intermediate heater (12) through the outlet diverter valve III (17) of the expander; the exhaust gas outlet side of the tube bundle evaporator (4) is passed through a tee The pipe is divided into two pipelines, one pipeline is connected to the intermediate heater (12) through the exhaust control valve I (18) and then connected to the exhaust pipe, and the other pipeline is connected to the exhaust pipe through the exhaust control valve II (19). The pipes are directly connected; in addition, the turbine (3) and the compressor (1) are connected into one body through the turbine-compressor coupling shaft (20). 2. A method for realizing the working process of the two-stage single-screw expander organic Rankine cycle diesel engine tail gas waste heat utilization system as claimed in claim 1, is characterized in that: 1) When the diesel engine is in low-speed and low-load conditions, the system starts the low-temperature waste heat recovery cycle system First, the expander outlet diverter valve II (16), expander outlet diverter valve III (17) and exhaust control valve I (18) are closed by the electronic control system, and the expander outlet diverter valve I (15) and exhaust control valve are closed. Valve II (19) is opened; the low temperature circulation system is mainly composed of tube bundle evaporator (4), single screw expander I (5), plate condenser (9), liquid storage tank (10), and working medium pump (11) , wherein the single-screw expander I (5) and the magnetic powder dynamometer I (6) are connected through the coupling shaft I (21) to measure the output shaft work, the plate condenser (9), the cooling tower (13) and the adjustable The flow pumps (14) are connected in turn to form a closed circuit to form a cooling system. The specific working process is: the air is compressed by the compressor (1) and then enters the diesel engine (2), and is discharged from the diesel engine (2) after combustion and expansion in the cylinder. , the exhaust gas enters the turbine (3) and drives the turbine (3) to rotate to drive the compressor (1) to work. The high-temperature gas from the turbine (3) releases heat through the tube-bundle evaporator (4) and then is exhausted through the exhaust pipe. Into the atmosphere, the organic matter absorbs the heat released by the exhaust gas of the diesel engine in the tube-bundle evaporator (4) and converts it into a gaseous state, and the generated gas pushes the single-screw expander I (5) to expand and do work. This process can be regarded as the adiabatic expansion of the working fluid During the process, the gas is cooled and decompressed to form exhaust gas, which enters the plate condenser (9) to release heat at a constant pressure and is cooled to liquid. After the liquid enters the liquid storage tank (10), it is pumped by the working medium pump (11) Carry out a new round of circulation in the tube bundle evaporator (4); 2) When the diesel engine is under medium-high speed and medium-high load conditions, the system starts the medium-temperature waste heat recovery circulation system First, the expander outlet diverter valve I (15), expander outlet diverter valve III (17) and exhaust control valve I (18) are closed by the electronic control system, and the expander outlet diverter valve II (16) and exhaust control valve are closed. Valve II (19) is opened; the medium temperature circulation system is mainly composed of tube bundle evaporator (4), single screw expander I (5), single screw expander II (7), plate condenser (9), liquid storage tank (10 ), a working medium pump (11), wherein the single-screw expander I (5) is connected to the magnetic powder dynamometer I (6) through the coupling shaft I (21) to measure the output shaft work, and the single-screw expander II ( 7) Connect with the magnetic powder dynamometer II (8) through the coupling shaft II (22) to measure the output shaft work, and the plate condenser (9), cooling tower (13) and adjustable flow pump (14) are connected in sequence to form A closed circuit constitutes a cooling system, and the specific working process is as follows: the air is compressed by the compressor (1) and then enters the diesel engine (2), and is discharged by the diesel engine (2) after combustion and expansion in the cylinder, and the exhaust gas enters the turbine (3) Push the turbine (3) to rotate to drive the compressor (1) to work. The high-temperature gas from the turbine (3) releases heat from the tube-bundle evaporator (4) and then is discharged into the atmosphere through the exhaust pipe. The heat released by absorbing the diesel engine exhaust in the evaporator (4) is converted into a gaseous state, and the gas pushes the single-screw expander I (5) to expand and do work, and the temperature and pressure are lowered to form exhaust gas. At this time, the exhaust gas still has high energy and can be Continue to recover, so the exhaust gas needs to be connected to the single-screw expander II (7) to continue to expand and work. After the gas is further lowered in temperature and pressure, it enters the plate condenser (9) and is cooled to liquid at constant pressure. After the liquid tank (10) is pumped into the tube bundle evaporator (4) by the working medium pump (11), a new round of circulation is carried out; 3) When the diesel engine is in high-speed and high-load conditions, the system starts the high-temperature waste heat recovery cycle system First, the expander outlet diverter valve I (15), expander outlet diverter valve II (16), and exhaust control valve II (19) are closed by the electronic control system, and the expander outlet diverter valve III (17) and exhaust control valve are closed. Valve I (18) is opened; the high-temperature circulation system is mainly composed of tube-bundle evaporator (4), single-screw expander I (5), intermediate heater (12), single-screw expander II (7), plate condenser (9 ), a liquid storage tank (10), and a working medium pump (11), in which the single-screw expander I (5) is connected to the magnetic powder dynamometer I (6) through the coupling shaft I (21) to measure the output shaft work , the single-screw expander II (7) is connected with the magnetic powder dynamometer II (8) through the coupling shaft II (22) to measure the output shaft work, the plate condenser (9), the cooling tower (13) and the adjustable flow The pumps (14) are connected in turn to form a closed circuit to form a cooling system. The specific working process is: the air is compressed by the compressor (1) and then enters the diesel engine (2), and is discharged by the diesel engine (2) after combustion and expansion in the cylinder. The exhaust gas enters the turbine (3) and drives the turbine (3) to rotate to drive the compressor (1) to work. The high-temperature gas from the turbine (3) releases heat through the tube-bundle evaporator (4) and then enters the intermediate heater ( 12) After continuing to release heat, it is directly discharged into the atmosphere through the exhaust pipe. This is because when the diesel engine is under high-speed and high-load conditions, the energy of the exhaust gas is not fully recovered in the tube-bundle evaporator (4), Connecting intermediate heater (12) behind it can reclaim tail gas energy more; Organic matter absorbs the heat released by diesel engine tail gas in tube bundle evaporator (4) and converts into gaseous state, and the gas that produces pushes single-screw expander 1 (5 ) expands to do work, the gas is cooled and depressurized to form exhaust gas, and the exhaust gas further absorbs the heat released by the exhaust gas of the diesel engine in the intermediate heater (12). ) continues to expand and do work, and the gas enters the plate condenser (9) after further cooling and decompression to release heat at a constant pressure and is cooled to liquid. After the liquid enters the liquid storage tank (10), it is pumped by the working fluid pump (11) Carry out a new round of circulation in the tube bundle evaporator (4).

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