CN211851944U - A power generation system for waste heat recovery of electrolyzers - Google Patents

Abstract

The utility model relates to a power generation system for electrolysis trough waste heat recovery, include: the gas compressor, the heat conduction device arranged outside the electrolytic bath, the primary circulation turbine, the primary circulation generator and the primary circulation cooler are arranged on the outer side of the electrolytic bath; the gas compressor is connected with a heat conduction device through a pipeline, the heat conduction device is connected with a first-stage circulating turbine pipeline, a first-stage circulating turbine is connected with a first-stage circulating cooler through a pipeline, the first-stage circulating cooler is connected with the gas compressor through a pipeline, and a first-stage circulating generator is connected with a first-stage circulating turbine shaft. The secondary waste heat generator set comprises a circulating pump, a secondary circulating turbine, a secondary circulating generator and a secondary circulating cooler; the circulating pump is connected with a pipeline of a first-stage circulating cooler, the first-stage circulating cooler is connected with a pipeline of a second-stage circulating turbine, the second-stage circulating turbine is connected with a pipeline of a second-stage circulating cooler, the second-stage circulating cooler is connected with a pipeline of the circulating pump, and the second-stage circulating turbine is connected with a shaft of a second-stage generator. The utilization rate of the waste heat of the electrolytic cell is improved.

Description

A power generation system for waste heat recovery of electrolyzers

technical field

The utility model relates to the technical field of waste heat power generation, in particular to a power generation system used for waste heat recovery of electrolyzers.

Background technique

my country's current electrolytic aluminum production capacity is more than 30 million tons, mostly produced by electrolysis. There is about 50% heat dissipation loss in the production process of aluminum electrolytic cells, mainly by radiation and convection to the atmospheric environment. At present, there is no good heat recovery and utilization method.

In the prior art, heat exchange equipment is generally directly installed on the side wall of the electrolytic cell, and the fluid is used to take part of the heat out of the electrolytic cell to realize the utilization of waste heat. The utilization method is single and the efficiency is not high. Much of the waste heat remains unusable and causes thermal pollution to the environment.

Therefore, the existing technology still needs to be improved and developed.

Utility model content

In view of the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a power generation system for the recovery of the waste heat of the electrolytic cell, which aims to solve the problem of low utilization efficiency of the residual heat of the electrolytic cell in the prior art.

The technical scheme adopted by the present invention for solving the above-mentioned technical problems is as follows:

A power generation system for waste heat recovery of electrolyzers, comprising:

A first-stage waste heat generator set, including a gas compressor, a heat-conducting device arranged outside the electrolytic cell, a first-stage circulating turbine, a first-stage circulating generator and a first-stage circulating cooler;

The outlet end of the gas compressor is connected with the inlet end pipeline of the heat conduction device, the outlet end of the heat conduction device is connected with the input end pipeline of the first-stage circulation turbine, and the output end of the first-stage circulation turbine It is connected with the pipeline of the first inlet end of the first-stage circulating cooler, the first outlet end of the first-stage circulating cooler is connected with the pipeline of the inlet end of the gas compressor, and the first-stage circulating generator is connected to the One-stage circulating turbine shaft connection;

Secondary waste heat generator set, including circulation pump, secondary circulation turbine, secondary circulation generator, secondary circulation cooler;

The outlet end of the circulating pump is connected with the second inlet end of the first-stage circulating cooler, and the second outlet end of the first-stage circulating cooler is connected with the pipeline at the inlet end of the second-stage circulating turbine. The outlet end of the circulation turbine is connected with the pipeline at the inlet end of the secondary circulation cooler, the outlet end of the secondary circulation cooler is connected with the pipeline at the inlet end of the circulation pump, and the secondary circulation turbine is connected with the secondary power generation Crankshaft connection.

In the power generation system for recovering the waste heat of an electrolyzer, wherein a channel through which the first working medium passes is arranged inside the heat conduction device.

In the power generation system for waste heat recovery of electrolyzers, wherein the first working medium is gas.

In the power generation system for waste heat recovery of electrolyzers, wherein the heat conduction device is a metal plate.

In the power generation system for waste heat recovery of an electrolytic cell, wherein the heat conduction device is arranged in the thermal insulation layer of the electrolytic cell.

The power generation system for the waste heat recovery of the electrolytic cell further comprises a thermoelectric module, and the thermoelectric module is arranged on the surface of the heat conduction device near the inner side of the electrolytic cell.

In the power generation system for waste heat recovery of an electrolytic cell, the thermal insulation layer includes an thermal insulation layer on the side wall of the electrolytic cell, a molten pool thermal insulation layer at the bottom of the electrolytic cell, and a thermal insulation ash layer on the upper part of the electrolytic cell.

In the power generation system for waste heat recovery of electrolyzers, thermoelectric modules are provided on both sides of the heat conduction device in the thermal insulation ash layer.

In the power generation system for waste heat recovery of electrolyzers, wherein the secondary waste heat generating set includes a second working fluid, and the second working fluid is a binary working fluid.

In the power generation system for waste heat recovery of electrolyzers, wherein the second working medium is tetrafluoroethane or freon.

Beneficial effects: The power generation system for the waste heat recovery of the electrolyzer provided by the utility model utilizes the waste heat in a combined manner of Brayton cycle and organic Rankine cycle, improves the efficiency of thermoelectric conversion, and improves the utilization rate of waste heat.

Description of drawings

FIG. 1 is a schematic diagram of a power generation system for waste heat recovery of an electrolyzer provided by an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an electrolytic cell provided with a power generation system for waste heat recovery of an electrolytic cell provided by an embodiment of the present invention, and a heat conduction device and a thermoelectric module are arranged inside.

Figure 3 is a comparison diagram of the electrolyzer with and without a heat recovery system.

Figure 4 is a schematic diagram of the heat transfer process of the electrolytic cell.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present utility model more clear and definite, the present utility model is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not intended to limit the present invention.

The serial numbers themselves, such as "first", "second", etc., for the components herein are only used to distinguish the described objects, and do not have any order or technical meaning. The "connection" and "connection" mentioned in this utility model, unless otherwise specified, include both direct and indirect connections (connections). In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", right, "vertical", "horizontal", "top", The orientation or positional relationship indicated by "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. is used for the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and The description is simplified rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In the present invention, unless otherwise expressly specified and defined, a first feature "on" or "under" a second feature may be in direct contact with the first and second features, or the first and second features through an intermediary indirect contact. Also, the first feature being "above", "over" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

As shown in FIG. 1 , the power generation system for the waste heat recovery of the electrolytic cell disclosed in the present invention includes: a first-stage waste heat generator set 10 , including a gas compressor 110 , a heat conduction device 120 disposed outside the electrolytic cell 30 , a The first-stage circulating turbine 130, the first-stage circulating generator 140 and the first-stage circulating cooler 150; wherein, the installation position of the heat conduction device 120 can be set according to actual needs, usually at the bottom and/or side of the electrolytic cell. The outside here is relative to the interior space of the cell.

The outlet end of the gas compressor 110 is connected to the pipeline of the inlet end of the heat conduction device 120, the outlet end of the heat conduction device 120 is connected to the pipeline of the input end of the first-stage circulating turbine 130, and the first-stage circulating turbine The output end of the flat 130 is connected to the pipeline of the first inlet end of the first-stage circulating cooler 150, the first outlet end of the first-stage circulating cooler 150 is connected to the pipeline of the inlet end of the gas compressor 110, and the The first-stage circulation generator 140 is axially connected with the first-stage circulation turbine 130;

The secondary waste heat generator set 20 includes a circulation pump 210, a secondary circulation turbine 220, a secondary circulation generator 230, and a secondary circulation cooler 240;

The outlet end of the circulating pump 210 is connected to the second inlet end of the first-stage circulating cooler 150 with a pipeline, and the second outlet end of the first-stage circulating cooler 150 is connected to the second-stage circulating turbine 220. The outlet end of the secondary circulation turbine 220 is connected to the inlet end of the secondary circulation cooler 240 by a pipeline, and the outlet end of the secondary circulation cooler 240 is connected to the inlet end of the circulation pump 210 by a pipeline. The turbine 220 is shaft-connected to the secondary generator 230 .

In this embodiment, the first-stage waste heat generating set adopts the Brayton cycle, using gas as the heat exchange medium, and the second-stage waste heat generating set adopts the organic Rankine cycle, and the overall waste heat is improved by secondary recovery of waste heat. usage efficiency. Among them, the first-stage Brayton cycle can use various gases, such as nitrogen, carbon dioxide, air and so on. Since a large number of exposed copper bars, electrodes, etc. are arranged around the electrolytic cell, if liquid is used as the heat exchange medium, once leakage occurs, it may pose a threat to the electrical safety of the electrolytic cell. The use of gas as the heat exchange working medium can well avoid the damage to the electrolytic cell caused by the leakage of the heat exchange working medium.

In one or more embodiments, the heat conduction device 120 is used to conduct the heat released from the electrolytic cell to the working medium of the first-stage waste heat generating unit, so as to increase the temperature of the working medium. The heat-conducting device 120 may be a metal plate with good heat conduction, such as a copper plate, and a through channel is opened in the middle of the copper plate, through which the heat exchange working medium can pass. Of course, the heat-conducting device may also adopt a manner such as arranging heat-conducting pipes between two layers of metal copper plates, so as to realize the recovery of the heat released by the electrolytic cell.

In this embodiment, the Brayton cycle process is as follows: first, the gas working medium used for heat exchange, such as carbon dioxide gas, is pressurized by the gas compressor 110 to provide pressure for the cycle, and the temperature of the gas will also be in the process of compression. After rising, the pressurized gas enters the heat conduction device (heat transfer channel) arranged outside the electrolytic cell, absorbs the heat released from the electrolytic cell, and recovers part of the heat originally lost to the environment. After the heat exchange gas (working fluid) flows out from the heat transfer channel, the temperature further rises and enters the first-stage circulating turbine. After the expansion is done and the shaft work is output, the temperature and pressure of the heat exchange gas both drop, but the temperature is still high, and the flow rate is high. After cooling by the primary circulating cooler and transferring the heat to the secondary waste heat generator set, it returns to the inlet of the gas compressor and enters the next cycle.

Due to the poor thermal conductivity of the gas itself, it will not greatly affect the original temperature of the original electrolytic cell, and will not affect the normal operation of the electrolytic cell. At the same time, the heat exchange process of the heat exchange gas in the heat conduction device can be effectively regulated by adjusting the arrangement position of the heat conduction device, the flow rate of the heat exchange gas and the inlet temperature, etc.

In this embodiment, the two-stage waste heat generator set adopts the organic Rankine cycle, and the cycle process is as follows: the circulating pump pumps the second working medium into the first-stage circulating cooler to absorb the heat released from the first-stage circulating cooler, and then evaporates and heats up, Then enter the secondary turbine, expand and do work, enter the secondary circulating cooler to cool down and condense after cooling and depressurizing, and then be sent to the primary circulating cooler by the circulating pump for the next cycle. Wherein, the second working medium can be a binary working medium, such as tetrafluoroethane or freon.

In one or more embodiments, as shown in FIG. 2 , the heat conduction device 120 is a heat conduction pipe with a flat surface and a central part, which is arranged in the bottom insulation layer (melt pool insulation layer) of the electrolytic cell and the insulation of the side wall of the electrolytic cell. The heat conduction device is arranged in the thermal insulation layer, which can avoid the relative stability of heat exchange of the heat conduction device and avoid large temperature fluctuations, which is beneficial to the stable operation of the power generation equipment.

In one embodiment, a thermoelectric module 160 is further disposed on the heat conduction device 120, and the thermoelectric module 160 is disposed close to the heat conduction device 120. As shown in FIG. 2, in the thermal insulation layer of the side wall of the electrolytic cell, the vertically disposed heat conduction The side of the device close to the inside of the electrolytic cell is provided with a thermoelectric module, and the upper surface (closer to the inside of the electrolytic cell) of the heat conduction device arranged horizontally in the thermal insulation layer at the bottom of the electrolytic cell is provided with a thermoelectric module, that is, the thermoelectric module is arranged on the heating surface of the heat conduction device .

In one embodiment, an insulating ash layer 170 is provided at the opening of the electrolytic cell, and a heat-conducting device and thermoelectric modules 160 disposed on both sides of the heat-conducting device are provided in the insulating ash layer 170, so that the heat emitted at the opening of the electrolytic cell can be fully utilized. heat to maximize the heat recovery efficiency.

In this embodiment, the thermoelectric module is directly laid on the heating surface of the heat conduction device, so that the thermoelectric material can directly convert part of the heat into electrical energy by utilizing the temperature difference between the inside and outside formed during the gas heat exchange process, thereby improving the efficiency of the system's thermoelectric conversion; , In extreme cases, such as when the electrolytic cell starts to heat up, it can also supply power to the thermoelectric module, so that the thermoelectric module can run in reverse, and the heat of the heat transfer device (heat transfer pipe) gas is reversely transported to the electrolytic cell side, which can be used for electrolysis. The groove plays the role of active heat preservation, as shown in the working mode 2 in Figure 4.

As shown in Figures 3-4, part A in Figure 3 shows that a heat conduction device and a thermoelectric module are provided in the insulation layer of the electrolytic cell, and part B shows that no heat conduction device and thermoelectric module are provided. That is, part A represents an electrolytic cell with waste heat recovery, and part B represents an electrolytic cell without waste heat recovery. Among them, the molten pool in Fig. 4 is called the electrolytic cell in the text. The first working mode is that under normal circumstances, after the molten pool dissipates heat and undergoes two-stage heat recovery, part of the heat is dissipated into the air.

To sum up, the utility model provides a power generation system for waste heat recovery of an electrolytic cell, comprising: a first-stage waste heat generator set, including a gas compressor, a heat conduction device arranged outside the electrolytic cell, a first-stage circulating penetrator. Flat, primary cycle generator and primary cycle cooler;

The outlet end of the gas compressor is connected with the inlet end pipeline of the heat conduction device, the outlet end of the heat conduction device is connected with the input end pipeline of the first-stage circulation turbine, and the output end of the first-stage circulation turbine It is connected with the pipeline of the first inlet end of the first-stage circulating cooler, the first outlet end of the first-stage circulating cooler is connected with the pipeline of the inlet end of the gas compressor, and the first-stage circulating power generation is connected with the first-stage circulating cooler. Stage circulating turbine shaft connection;

The secondary waste heat generator set includes a circulation pump, a secondary circulation turbine, a secondary circulation generator, and a secondary circulation cooler; the outlet end of the circulation pump is connected to the second inlet end of the primary circulation cooler with a pipeline, The second outlet end of the primary circulating cooler is connected with the inlet pipe of the secondary circulating turbine, and the outlet end of the secondary circulating turbine is connected with the inlet pipe of the secondary circulating cooler. The outlet end of the circulating cooler is connected with the inlet end of the circulating pump, and the secondary circulating turbine is connected with the shaft of the secondary generator. By adopting the combination of Brayton cycle and organic Rankine cycle to utilize waste heat, the efficiency of thermoelectric conversion is improved, and the utilization rate of waste heat is improved.

It should be understood that the application of the present invention is not limited to the above-mentioned examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above descriptions. All these improvements and transformations should belong to the protection of the appended claims of the present invention. scope.

Claims (6)

1. A power generation system for electrolysis cell waste heat recovery, comprising:

the first-stage waste heat generator set comprises a gas compressor, a heat conduction device arranged outside the electrolytic bath, a first-stage circulating turbine, a first-stage circulating generator and a first-stage circulating cooler;

the outlet end of the gas compressor is connected with the inlet end pipeline of the heat conduction device, the outlet end of the heat conduction device is connected with the input end pipeline of the primary circulation turbine, the output end of the primary circulation turbine is connected with the first inlet end pipeline of the primary circulation cooler, the first outlet end of the primary circulation cooler is connected with the inlet end pipeline of the gas compressor, and the primary circulation generator is connected with the primary circulation turbine shaft;

the secondary waste heat generator set comprises a circulating pump, a secondary circulating turbine, a secondary circulating generator and a secondary circulating cooler;

the outlet end of the circulating pump is connected with a second inlet end pipeline of the first-stage circulating cooler, a second outlet end of the first-stage circulating cooler is connected with an inlet end pipeline of the second-stage circulating turbine, an outlet end of the second-stage circulating turbine is connected with an inlet end pipeline of the second-stage circulating cooler, an outlet end of the second-stage circulating cooler is connected with an inlet end pipeline of the circulating pump, and the second-stage circulating turbine is connected with a second-stage circulating generator shaft.

2. The power generation system for electrolysis cell waste heat recovery according to claim 1, wherein the heat conduction device is internally provided with a channel for the first working medium to pass through.

3. The power generation system for electrolysis cell waste heat recovery according to claim 1, wherein the heat conducting means is disposed in an insulation layer of the electrolysis cell.

4. The power generation system for electrolysis cell waste heat recovery according to claim 1, further comprising a thermoelectric module disposed on the heated surface of the heat conducting means.

5. The power generation system for electrolysis cell waste heat recovery according to claim 3, wherein the insulation layer comprises an electrolysis cell side wall insulation layer, a molten bath insulation layer at the bottom of the electrolysis cell, and an insulation ash layer at the upper part of the electrolysis cell.

6. The power generation system for electrolysis cell waste heat recovery according to claim 5, wherein the thermal conduction means in the insulating ash layer is provided with thermoelectric modules on both sides.

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