CN116576039A - Waste heat recycling structure - Google Patents

Abstract

The invention discloses a waste heat recycling structure, which is used to drive a working machine with a rotating shaft, comprising a heat absorber, a steam generating device, and a condenser with a storage container, the storage container is provided with an evaporation medium, and the heat absorber includes The first pipeline, the second pipeline, and the working steps of the waste heat recovery and utilization structure include: sending the low-heat fluid into the first pipeline with a pumping device, and sending the liquid evaporation medium in the storage container into the second pipeline; the low-heat fluid in the first pipeline The fluid exchanges heat with the evaporating medium in the second pipeline, so that the evaporating medium boils to form steam; the gaseous evaporating medium can drive the rotating shaft of the working machine to do work; the evaporating medium whose temperature is lowered after doing work returns to the condenser to cool down and condense into a liquid ; The liquid evaporating medium is re-sent into the second pipeline for circulating heat exchange and doing work. The invention can effectively improve the heat utilization efficiency of the existing thermal energy machinery, and adapt the thermal energy mechanical energy to more low-temperature heat sources.

Description

A waste heat recycling structure

technical field

The invention relates to the technical field of thermal energy machinery, in particular to a waste heat recycling structure.

Background technique

We know that the existing thermal energy machinery usually heats water flow through the heat generated by burning coal, oil, gas and other fossil materials, and then forms high-temperature and high-pressure steam—that is, high-temperature fluid, and then uses high-temperature fluid to drive the rotation shaft of the working machine to rotate. acting. For example, a typical thermal power generation is to use steam to drive the rotor of the generator to rotate to generate electricity and output electric energy to the outside. That is to say, a thermal machine is a device that converts thermal energy into mechanical energy or electrical energy.

With the continuous strengthening of people's awareness of environmental protection, a large number of hydropower, wind power, and solar power generation equipment have appeared. aforementioned thermomechanical

However, the existing thermal energy machinery has the following technical deficiencies: First, although the temperature of the steam after work has been reduced, it still has a relatively high temperature, and people need to condense the low-temperature steam into liquid water through a corresponding cooling device, so that A lot of precious heat energy is wasted. That is to say, the heat utilization efficiency of the existing thermal energy machinery is too low. Secondly, for some "low-temperature" fluid heat sources such as groundwater, because high-temperature and high-pressure steam cannot be formed, it cannot directly drive the rotation shaft of the machine tool to rotate, and thus cannot make full use of its internal heat energy.

Contents of the invention

The purpose of the present invention is to provide a waste heat recovery and utilization structure, which can effectively improve the heat utilization efficiency of the existing thermal machinery, and make the thermal machinery adaptable to more "low temperature" fluid heat sources.

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

A waste heat recovery and utilization structure for driving a working machine with a rotating shaft, comprising a heat absorber for heat exchange, a steam generating device, a condenser with a storage container, and the storage container is provided with a fluid-like evaporation Medium, the heat absorber includes a first pipeline for circulating a low-heat fluid, a second pipeline for circulating an evaporating medium, the boiling point of the evaporating medium is lower than 150°C, and the temperature of the low-heating fluid is higher than that of the evaporating medium boiling point, the working steps of the waste heat recovery structure include:

a. Use a pumping device to send the low-heat fluid into the first pipeline, and send the liquid evaporation medium in the storage container into the second pipeline;

b. The low-heat fluid in the first pipeline exchanges heat with the evaporating medium in the second pipeline, so that the evaporating medium boils to form steam;

c. The gaseous evaporation medium can drive the rotating shaft of the working machine to do work;

d. After doing work, the evaporating medium whose temperature is lowered returns to the condenser to cool down and condense into a liquid;

e. The liquid evaporating medium is re-sent into the second pipeline for heat exchange and work.

It should be noted that the working machine here can be a generator or other power machinery, and the function of the waste heat recovery and utilization structure of the present invention is to heat the evaporation medium with the heat of the low-heat fluid, make it boil and vaporize, and then pass it through the pump. The delivery device first sends low-temperature low-heat fluid (such as residual hot water or steam after work in the thermal energy machine, or even geothermal water) into the first pipeline, and at the same time sends the liquid evaporation medium in the storage container into the second pipeline. Of course, the boiling point of the evaporating medium here should be lower than the temperature of the low-heat fluid, so as to ensure that the evaporating medium is vaporized after heat exchange, and then the working machine can be made to work by rotating the shaft, thereby effectively improving the heat utilization efficiency of the existing thermal energy machinery , and adapt thermomechanical energy to more "low temperature" fluid heat sources.

In particular, we can rationally select the material of the evaporation medium so that the boiling point of the evaporation medium is lower than 150°, so as to ensure the adaptation to more low-heat fluids.

Preferably, the evaporating medium is anhydrous ether, or n-pentane, or dichloromethane.

We know that the boiling point of anhydrous ether is 34.4°C, the boiling point of n-pentane is 36.1°C, and the boiling point of dichloromethane is 40°C. That is to say, the boiling points of the three materials are not higher than 40° C., so that the evaporation medium can be adapted to more low-heat fluids.

As a preference, a number of partition ribs evenly distributed in the circumferential direction and in the shape of a multi-head spiral are provided on the outside of the first pipe, and the second pipe is coaxially sleeved outside the first pipe, so that the second pipe and the first pipe A number of helical fluid channels separated by partition ribs are formed between them. The second pipe, the partition ribs and the first pipe are spirally bent together to form a helical heat exchange pipe with a pitch equal to the outer diameter of the second pipe. The middle diameter is 1/5-1/3 of the middle diameter of the heat exchange pipe.

In this scheme, the second pipe, the partition ribs and the first pipe are twisted together to form a spiral heat exchange pipe, which can maximize the increase of the first pipe, the second pipe without increasing the axial size of the heat exchange pipe. The length of the second pipe. In particular, on the outer side of the first pipe, there are several partition ribs evenly distributed in the circumferential direction and in the shape of a multi-head spiral, so that the spiral fluid channels separated from each other can be formed, and the middle diameter of the fluid channel is the middle diameter of the heat exchange pipe. 1/5-1/3 of that. Therefore, the length of the fluid channel is much longer than that of the first pipe and the second pipe, thereby effectively increasing the heat exchange time and area between the evaporating medium and the low-heat fluid, so that the heat of the low-heat fluid can be fully transferred to the evaporating medium.

Preferably, the working machine is a generator, which includes a shell with evaporating medium inlets at the front and rear ends, a stator set in the shell, and a rotor set on the rotating shaft that can rotate relative to the stator. The front and rear ends of the rotating shaft pass through Bearings are respectively supported on the front and rear ends of the casing, and impellers are respectively provided at the front and rear ends of the rotating shaft. In step c, the evaporating medium enters the casing through the evaporating medium inlet, and then drives the impeller to drive the rotor to rotate to generate electricity.

In this solution, the working machine is a generator with a rotating shaft, a rotor and a stator. In this way, the vaporized evaporation medium after heat exchange with the low-heat fluid enters the casing through the evaporation medium inlet, and then drives the impeller to drive the rotor to rotate to generate electricity.

In particular, the front and rear ends of the rotating shaft are respectively supported on the front and rear ends of the housing through bearings, and impellers are respectively provided at the front and rear ends of the rotating shaft, so that the axial force and radial force at the front and rear ends of the rotating shaft can be ensured. The forces cancel each other out to maintain balance.

Preferably, the housing includes a middle section with a stator, a front section and a rear section with an evaporating medium inlet, an annular medium channel is respectively provided at the front section and the rear section, and one end of the medium channel is connected to the evaporating medium inlet through an inner channel The other end communicates with the inlet of the condenser through the outer channel, and the pumping device includes a negative pressure pump arranged on the pipeline connecting the outer channel and the inlet of the condenser.

The casing of the present invention adopts a split structure, thereby facilitating manufacture and assembly. In particular, ring-shaped media channels are respectively provided in the front section and the rear section. In this way, the vaporized evaporating medium formed after heat exchange can enter the casing through the evaporating medium inlets of the front and rear sections respectively, and drive the impeller to rotate, then the evaporating medium enters the medium channel through the inner channel, and then enters the condenser through the outer channel Condensation in the liquid state. Since the pumping device includes a negative pressure pump arranged on the pipeline connecting the outer channel and the inlet of the condenser, a negative pressure can be formed in the medium channel, which is conducive to "sucking out" the evaporating medium and preventing the evaporating medium from being diffused in the shell.

Preferably, the bearing is arranged between the impeller and the rotor, the bearing includes an axial electromagnetic bearing and a radial electromagnetic bearing, and the bearings at the front and rear ends of the rotating shaft are arranged symmetrically.

Since the bearings at the front and rear ends of the rotating shaft are arranged symmetrically, the force balance at the front and rear ends of the rotating shaft can be ensured. The electromagnetic bearing has the function of no friction and no lubrication. In particular, the bearing is arranged between the impeller and the rotor, which is beneficial to the force balance of the impeller and the rotor on the front and rear sides of the bearing, and avoids bending of the rotating shaft due to force.

Therefore, the present invention has the following beneficial effects: it can effectively improve the heat utilization efficiency of the existing thermal energy machinery, and make the thermal energy mechanical energy adaptable to more "low temperature heat sources.

Description of drawings

A schematic diagram of a structure of a heat exchange device in Fig. 1 .

Figure 2 is a schematic structural view of the heat absorber.

Fig. 3 is a structural schematic diagram of the working machine.

In the figure: 1, heat absorber 11, first pipeline 12, second pipeline 13, partition rib 14, fluid channel 2, steam generating device 3, shell 31, evaporation medium inlet 32, stator 33, rotating shaft 34, Rotor 35, middle section 36, front section 37, rear section 38, medium channel 4, bearing 41, axial electromagnetic bearing 42, radial electromagnetic bearing 5, impeller.

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

A waste heat recovery and utilization structure, which is used to recover the heat energy contained in "low-temperature steam, liquid, geothermal water, biomass energy, gas turbine or internal combustion engine exhaust, industrial furnace flue gas and other low-heat fluids after doing work", and then recover it Thermal energy is used to drive a working machine with a rotating shaft, in order to improve the heat utilization efficiency of the existing thermal energy machinery and make the thermal energy mechanical energy adapt to more "low temperature" fluid heat sources.

Specifically, as shown in Figure 1 and Figure 2, the waste heat recovery structure includes a heat exchange device, a condenser with a storage container, and a fluid evaporation medium is provided in the storage container, and the heat exchange device includes a Heat absorber 1, steam generating device 2 for generating steam. The heat absorber includes a first pipeline 11 for circulating a low-heat fluid, and a second pipeline 12 for circulating an evaporating medium. Of course, the temperature of the low-heat fluid should be higher than the boiling point of the evaporating medium, so that the evaporating medium can be evaporated into steam. Since the temperature of the low heat fluid is generally between 90°C and 250°C, preferably, the boiling point of the evaporation medium is lower than 150°C. In addition, the working steps of the waste heat recovery structure include:

a. Use a pumping device to send the low-heat fluid into the first pipeline, and send the liquid evaporation medium in the storage container into the second pipeline;

b. The low-heat fluid in the first pipeline exchanges heat with the evaporating medium in the second pipeline. Since the temperature of the low-heat fluid is higher than the boiling point of the evaporating medium, the evaporating medium heats up and boils to form steam;

c. The gaseous evaporation medium can drive the rotating shaft of the working machine to do work;

d. After doing work, the evaporating medium whose temperature is lowered returns to the condenser to cool down and condense into a liquid;

e. The liquid evaporating medium is re-sent into the second pipeline for heat exchange and work.

Since the technical principle of the steam-driven working machine belongs to the prior art, it will not be described in detail in this embodiment.

It can be understood that we can reasonably select the material of the evaporation medium so that the boiling point of the evaporation medium is lower than 150° so as to match the temperature of the low heat fluid.

Preferably, the evaporation medium can be anhydrous ether with a boiling point of 34.4°C, or n-pentane with a boiling point of 36.1°C, or dichloromethane with a boiling point of 40°C, so that the evaporation medium can be adapted to more low-heat fluids.

As a preferred solution, we can arrange 3-4 partition ribs 13 evenly distributed in the circumferential direction on the outside of the first pipe, and arrange the partition ribs vertically in the radial direction within the cross section of the first pipe. In addition, the separating rib is helical around the first pipe. In addition, the second pipe is coaxially sleeved outside the partition ribs of the first pipe, thereby forming several helical fluid channels 14 separated from each other by the partition ribs between the second pipe and the first pipe. Specifically, the inner edge of the separating rib is sealed and welded to the outer wall of the first pipe, and the outer edge of the separating rib is sealed and welded to the inner wall of the second pipe. Then, the second pipe, the separating rib and the first pipe are assembled together For the spirally bent heat exchange pipe, preferably, we can make the pitch of the spiral heat exchange pipe equal to the outer diameter of the second pipe. That is to say, two adjacent turns of the helical heat exchange pipe are close to each other, so that the length of the first pipe and the second pipe can be increased to the greatest extent without increasing the axial dimension of the heat exchange pipe. . In addition, we can make the middle diameter of the fluid passage 1/5-1/3 of the middle diameter of the heat exchange pipe, so that the length of the fluid passage is much longer than the length of the first pipe and the second pipe, and then effectively lift the evaporating medium The time and area of heat exchange with the low-heat fluid, so that the heat of the low-heat fluid can be fully transferred to the evaporation medium, and the heat energy of the low-heat fluid can be utilized to the greatest extent.

As another preferred solution, as shown in Figure 3, the working machine is a generator, specifically, the working machine includes a housing 3 with evaporating medium inlets 31 at the front and rear ends, a stator 32 arranged in the housing, and a stator 32 arranged on the rotating shaft. 33 and the rotor 34 that can rotate relative to the stator, the front and rear ends of the rotating shaft are respectively supported on the front and rear ends of the housing through bearings 4 . Of course, we also need to arrange the impellers 5 at the front and rear ends of the rotating shaft respectively. In this way, in step c, when the evaporating medium enters the casing through the evaporating medium inlet, the respective impellers can be driven to rotate, and then the rotors are driven to rotate to generate electricity.

It should be noted that since the front and rear ends of the rotating shaft are supported on the end of the housing through bearings, and the front and rear ends of the rotating shaft are respectively provided with impellers, therefore, the axial force and diameter of the front and rear ends of the rotating shaft can be ensured. The axial forces cancel each other out to maintain balance.

Further, the casing adopts a split structure, so as to facilitate manufacture and assembly. Specifically, the housing includes a middle section 35, a front section 36 spliced and assembled at the front end of the middle section, and a rear section 37 spliced and assembled at the rear end of the middle section, and the stator is arranged in the middle section, and the openings of the front section and the rear section form an evaporation medium inlet. Of course, the rotating shaft should be provided with a rotor at a position corresponding to the stator, and an annular cooling channel should be provided outside the middle section to cool down the middle section that is heated up during power generation. Since the general structure of the generator belongs to the prior art, it will not be described in detail in this embodiment.

In addition, ring-shaped medium passages 38 are respectively provided at the positions corresponding to the impellers in the front section and the rear section. One end of the medium passage communicates with the inlet of the evaporating medium through the inner passage, and the other end communicates with the inlet of the condenser through the outer passage. In this way, the vaporized evaporating medium formed after heat exchange can enter the casing through the evaporating medium inlets of the front section and the rear section respectively, and drive the impeller to rotate, then the evaporating medium enters the medium channel through the inner channel, and then flows back to the condensate through the outer channel. Condensation in the container is liquid. In addition, the pumping device includes a negative pressure pump installed on the pipeline connecting the outer channel and the condenser inlet, so as to form a negative pressure in the medium channel, so as to "suck out" the evaporation medium after the drive impeller has done work, and avoid the evaporation medium in the casing. Diffuse in the body.

In addition, the bearings include axial electromagnetic bearings 41 and radial electromagnetic bearings 42, and the bearings at the front and rear ends of the rotating shaft are symmetrically arranged to ensure the force balance at the front and rear ends of the rotating shaft. In addition, the bearing is preferably arranged between the impeller and the rotor, which not only facilitates the force balance between the impeller and the rotor on the front and rear sides of the bearing, but also avoids bending of the rotating shaft due to force.

Claims (6)

1. A waste heat recovery and utilization structure, which is used to drive a working machine with a rotating shaft, comprising a heat absorber for heat exchange, a steam generating device, and a condenser with a storage container, the storage container is provided with a fluid-like The evaporating medium, the heat absorber includes a first pipeline for circulating a low-heat fluid and a second pipeline for circulating an evaporating medium, wherein the boiling point of the evaporating medium is lower than 150°C, and the low-heat fluid The temperature is higher than the boiling point of the evaporation medium, and the working steps of the waste heat recovery structure include: Use a pumping device to send the low-heat fluid into the first pipeline, and send the liquid evaporation medium in the storage container into the second pipeline; The low-heat fluid in the first pipeline exchanges heat with the evaporation medium in the second pipeline, so that the evaporation medium boils to form steam; The gaseous evaporation medium can drive the rotating shaft of the machine tool to rotate and do work; After doing work, the evaporating medium whose temperature is lowered returns to the condenser to cool down and condense into a liquid; The liquid evaporating medium is re-sent into the second pipeline for heat exchange and work. 2. A waste heat recycling structure according to claim 1, characterized in that the evaporating medium is anhydrous ether, or n-pentane, or methylene chloride. 3. A waste heat recovery and utilization structure according to claim 2, characterized in that, on the outside of the first pipe, there are several partition ribs evenly distributed in the circumferential direction and in the shape of a multi-head spiral, and the second pipe is coaxial It is sleeved on the outside of the first pipe, so that several helical fluid channels separated by partition ribs are formed between the second pipe and the first pipe. The second pipe, the partition ribs and the first pipe are coiled and bent together to form a pitch The spiral heat exchange pipe is equal to the outer diameter of the second pipe, and the middle diameter of the fluid channel is 1/5-1/3 of the middle diameter of the heat exchange pipe. 4. A waste heat recovery and utilization structure according to claim 1, characterized in that the working machine is a generator, comprising a shell with evaporation medium inlets at the front and rear ends, a stator set in the shell, and a rotating The rotor on the shaft and can rotate relative to the stator, the front and rear ends of the rotating shaft are respectively supported on the front and rear ends of the housing through bearings, and impellers are respectively arranged at the front and rear ends of the rotating shaft. In step c, the evaporating medium passes through the evaporating medium The inlet enters the casing, and then drives the impeller to drive the rotor to rotate to generate electricity. 5. A waste heat recovery and utilization structure according to claim 1, characterized in that, the housing includes a middle section provided with a stator, a front section and a rear section provided with an evaporation medium inlet, and the front section and the rear section are respectively provided with An annular medium channel, one end of the medium channel communicates with the inlet of the evaporating medium through the inner channel, and the other end communicates with the inlet of the condenser through the outer channel, and the pumping device is arranged on the pipeline connecting the outer channel and the inlet of the condenser negative pressure pump. 6. A waste heat recovery and utilization structure according to claim 1, wherein the bearing is arranged between the impeller and the rotor, the bearing includes an axial electromagnetic bearing and a radial electromagnetic bearing, and the bearings at the front and rear ends of the rotating shaft are symmetrical set up.