Methanol gas turbine and ORC coupled electrolytic aluminum energy utilization device system and method

Abstract

The invention provides a methanol gas turbine and ORC coupled electrolytic aluminum energy utilization device system and method. The energy utilization device system comprises a methanol gas turbine power generation module, a methanol preheating module, an ORC power generation module, an electrolytic aluminum module and an electrolytic aluminum flue gas waste heat utilization module. The methanol gas turbine power generation module, the methanol preheating module and the ORC power generation module are connected in sequence; the methanol gas turbine power generation module and the ORC power generation module are both connected with the electrolytic aluminum module; and the electrolytic aluminum module is connected with the electrolytic aluminum flue gas waste heat utilization module. The methanol gas turbine power generation module, the ORC power generation module and the electrolytic aluminum module are coupled, and the methanol gas turbine power generation module uses green methanol as fuel to supply power to the electrolytic aluminum module, so that the development requirements of the electrolytic aluminum industry on green and low carbon are met; meanwhile, waste heat of high-temperature flue gas of the methanol gas turbine power generation module and waste heat of high-temperature waste gas generated by the electrolytic aluminum module are utilized, and the purposes of energy conservation and emission reduction are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive utilization of waste heat, and in particular to an energy utilization device system and method for coupling an electrolytic aluminum with a methanol gas turbine and ORC. Background Art

[0002] The electrolytic aluminum industry is a typical high-energy-consuming industry and a high-carbon emission industry, with the highest carbon emissions in my country's nonferrous metal industry. Electrolytic aluminum consumes a lot of electricity in the production process. At present, the main source of electricity is coal-fired power. The emissions from the power generation link in the electrolytic aluminum process account for as high as 78.8%, accounting for 59.7% of the carbon emission intensity of the entire primary aluminum production. The CO2 emissions generated in the power generation process are the largest source of greenhouse gas emissions for electrolytic aluminum enterprises, and are also the most important link in reducing their carbon emissions. Therefore, using green electricity instead of coal-fired power is the most effective measure for reducing carbon emissions in the electrolytic aluminum industry at this stage.

[0003] Gas turbines have the advantages of fast starting, high efficiency, good reliability and low emissions. They are the technical guarantee for efficient and clean utilization of energy, and are also one of the core power equipment for realizing energy structure adjustment. Especially with the gradual formation of a new power system with new energy as the main body, during the peak period of new energy power generation, excess electricity will be converted into hydrogen or liquid methanol for storage, and then when the demand for electricity is strong, it will be connected to the grid through hydrogen or methanol fuel gas turbines, thus realizing true green energy power generation.

[0004] Since hydrogen has a low volumetric energy storage density, the safety and portability of its storage and transportation greatly limit its development in the field of power generation. Methanol is a liquid at room temperature, more stable, safe, easy to transport, and can be stored for a long time. Its safety level is equivalent to that of gasoline, and it is considered to be a hydrogen energy carrier with great advantages and potential. Therefore, methanol is also a realistic and high-performance alternative fuel for gas turbines in the future. On the basis of existing gas turbines, it is necessary to modify the fuel system and turbine components to a certain extent.

[0005] In the gas turbine power generation link, the high-temperature flue gas emitted still has a relatively high heat content. In the electrolytic aluminum production process, the electrolytic cell also produces waste flue gas containing a large amount of heat. The exhaust temperature can reach up to 150°C, and even in winter it can reach 80-90°C. Obviously, the direct discharge of these high-temperature flue gases into the atmosphere will cause a huge waste of resources. Reasonable use of the above-mentioned high-temperature flue gases can not only achieve the goal of energy conservation and emission reduction, but also improve the economic benefits of the enterprise.

[0006] CN117449927A discloses a methanol gas engine combined cycle power generation device system and method, including a top cycle unit, a bottom cycle unit and a molten salt heat exchange unit; the top cycle unit includes a methanol gas engine module; the bottom cycle unit includes a supercritical carbon dioxide split recompression cycle module and an organic Rankine cycle module; the methanol gas engine module is connected to the supercritical carbon dioxide split recompression cycle module via the molten salt heat exchange unit. The invention realizes the cascade utilization of the waste heat of the exhaust gas discharged by the methanol gas engine module; the high-temperature gas at the outlet of the gas-organic working fluid heat exchange device is used for preheating the methanol fuel, thereby improving the cycle power generation efficiency of the entire power generation device system.

[0007] CN116517655A discloses a power generation system that couples electrolytic flue gas waste heat, compressed air waste heat and air energy storage, including a compressed air waste heat thermal energy unit, an air energy storage power generation unit, and an electrolytic flue gas waste heat power generation unit. In the compressed air waste heat thermal energy unit, air is supplied to users in one way, and stored in the other way after secondary boosting and secondary cooling; the air energy storage power generation unit releases the stored air, heats it, generates electricity, and then supplies it to users after reducing the pressure; the compressed air waste heat thermal energy unit exchanges heat with the electrolytic flue gas waste heat power generation unit through cooling water, and the air energy storage power generation unit absorbs the heat of organic matter in the electrolytic flue gas waste heat power generation unit. The electrolytic flue gas waste heat power generation unit uses the electrolytic flue gas waste heat to heat the organic matter, and the organic matter steam generates electricity. The invention can improve the utilization efficiency of electrolytic flue gas waste heat, realize the cascade utilization of waste heat, realize the deep peak regulation of the compressed air system of the electrolytic aluminum plant, and reduce venting.

[0008] However, the above-mentioned device system does not take into account the green and low-carbon power generation needs of the electrolytic aluminum industry, and the utilization rate of electrolytic aluminum waste heat on the power generation side needs to be further improved. Summary of the invention

[0009] In view of the problems existing in the prior art, the present invention provides a methanol gas turbine and ORC coupled electrolytic aluminum energy utilization device system and method, which couples a methanol gas turbine power generation module, an ORC power generation module and an electrolytic aluminum module, wherein the methanol gas turbine power generation module uses green methanol as fuel to power the electrolytic aluminum module, thereby meeting the electrolytic aluminum industry's demand for green and low-carbon development. At the same time, the high-temperature flue gas of the methanol gas turbine power generation module and the high-temperature exhaust gas generated by the electrolytic aluminum module are used as waste heat, thereby saving energy and reducing emissions while improving the economic benefits of the enterprise.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a methanol gas turbine and ORC coupled aluminum electrolysis energy utilization device system, the energy utilization device system comprising a methanol gas turbine power generation module, a methanol preheating module, an ORC power generation module, an aluminum electrolysis module and an aluminum electrolysis flue gas waste heat utilization module;

[0012] The methanol gas engine power generation module, the methanol preheating module and the ORC power generation module are connected in sequence; the methanol gas engine power generation module and the ORC power generation module are both connected to the electrolytic aluminum module; the electrolytic aluminum module is connected to the electrolytic aluminum flue gas waste heat utilization module.

[0013] The energy utilization device system structure of the methanol gas turbine and ORC coupled electrolytic aluminum of the present invention is reasonably designed. By coupling the methanol gas turbine power generation module and the ORC power generation module with the electrolytic aluminum module, the high-temperature flue gas generated by the methanol gas turbine power generation module is fully and reasonably utilized, which not only preheats the green fuel methanol entering the methanol gas turbine power generation module, but also further serves as a heat source for the ORC power generation module; the electric energy generated by the methanol gas turbine power generation module and the ORC power generation module is supplied to the electrolytic aluminum module for electrolytic aluminum production, and finally the flue gas waste heat is efficiently utilized through the electrolytic aluminum flue gas waste heat utilization module, thereby improving the power generation efficiency of the entire energy utilization device system and achieving the purpose of energy saving, consumption reduction and carbon reduction.

[0014] Preferably, the methanol gas engine power generation module comprises a compressor, a combustion chamber, a first turbine and a first generator which are connected in sequence.

[0015] Preferably, the compressor is coaxially connected to the first turbine.

[0016] Preferably, the methanol preheating module comprises a first heat exchange device.

[0017] Preferably, the first heat exchange device is connected to the first turbine via a first flue gas input duct.

[0018] Preferably, the first heat exchange device is connected to a methanol fuel input pipeline.

[0019] Preferably, the first heat exchange device is connected to the combustion chamber via a methanol fuel output pipeline.

[0020] Preferably, the ORC power generation module comprises a second heat exchange device, a second turbine, a first condensing device and a first working medium driving device which are cyclically connected.

[0021] Preferably, the second heat exchange device in the ORC power generation module is connected to the first heat exchange device via a first flue gas exhaust duct.

[0022] Preferably, the ORC power generation module further includes a second generator.

[0023] Preferably, the second generator is coaxially connected to the second turbine.

[0024] Preferably, the aluminum electrolysis module comprises an electrolytic cell.

[0025] Preferably, the aluminum electrolytic fume waste heat utilization module includes a waste heat thermal utilization module or a waste heat power generation utilization module.

[0026] Preferably, the waste heat utilization module includes a third heat exchange device, which can reduce the temperature of the electrolytic aluminum flue gas finally discharged, which is beneficial to prolonging the service life of the bags in the subsequent flue gas treatment and dust removal system.

[0027] Preferably, the third heat exchange device is connected to the electrolytic cell via a second flue gas input duct.

[0028] Preferably, the third heat exchange device is connected to the heat exchange medium input pipeline and the heat exchange medium output pipeline respectively.

[0029] Preferably, the waste heat power generation module comprises a fourth heat exchange device, a third turbine, a second condensing device and a second working medium driving device which are cyclically connected.

[0030] Preferably, the fourth heat exchange device in the waste heat power generation module is connected to the electrolytic cell via the second flue gas input pipeline.

[0031] Preferably, the waste heat power generation module also includes a third generator.

[0032] Preferably, the third generator is coaxially connected to the third turbine.

[0033] In a second aspect, the present invention further provides a method for energy utilization of a methanol gas turbine and ORC coupled to electrolytic aluminum, the energy utilization method being carried out using the energy utilization device system of the methanol gas turbine and ORC coupled to electrolytic aluminum described in the first aspect; the energy utilization method comprises the following steps:

[0034] (1) The methanol gas engine power generation module generates first electrical energy and generates first high-temperature flue gas; the first high-temperature flue gas enters the methanol preheating module to heat methanol, and then enters the ORC power generation module to generate second electrical energy; wherein the heated methanol enters the methanol gas engine power generation module to generate electricity;

[0035] (2) The first electric energy and the second electric energy are both supplied to the aluminum electrolysis module to perform aluminum electrolysis and simultaneously generate a second high-temperature flue gas;

[0036] (3) The second high-temperature flue gas enters the electrolytic aluminum flue gas waste heat utilization module for recycling.

[0037] The energy utilization method of the methanol gas turbine and ORC coupled electrolytic aluminum described in the present invention utilizes the methanol gas turbine power generation module and the ORC power generation module to generate the electric energy required by the electrolytic aluminum module, meeting the development needs of the electrolytic aluminum industry for green and low-carbon development. At the same time, the high-temperature flue gas generated by the methanol gas turbine power generation module and the high-temperature exhaust gas generated by the electrolytic aluminum module are comprehensively utilized for waste heat, achieving the effect of energy conservation and emission reduction, and improving the economic benefits of electrolytic aluminum production.

[0038] Preferably, the energy utilization method specifically comprises the following steps:

[0039] (1) After air enters the compressor of the methanol gas turbine power generation module and is compressed, it is burned in the combustion chamber with the methanol heated by the methanol preheating module to generate fuel gas to drive the first turbine to do work and drive the first generator to generate first electrical energy. The first high-temperature flue gas discharged by the first turbine enters the first heat exchange device of the methanol preheating module to heat the methanol.

[0040] The first organic working fluid exchanges heat with the first high-temperature flue gas from the first heat exchange device in the second heat exchange device in the ORC power generation module to form the first steam, the first steam enters the second turbine to expand and do work, and drives the second generator to generate second electric energy, the steam exhausted from the second turbine condenses into liquid in the first condensing device, and enters the second heat exchange device again through the first working fluid driving device to start the heat exchange cycle;

[0041] (2) The first electric energy and the second electric energy are both supplied to the electrolytic cell of the aluminum electrolysis module to electrolyze aluminum; the exhaust gas at the outlet of the electrolytic cell enters the third heat exchange device of the waste heat utilization module to exchange heat with the heat exchange medium;

[0042] Or the exhaust gas at the outlet of the electrolyzer enters the fourth heat exchange device of the waste heat power generation utilization module to exchange heat with the second organic working fluid. The second organic working fluid is heated to form a second steam. The second steam enters the third turbine to expand and do work, and drives the third generator to generate electricity. The steam exhausted from the third turbine is condensed into a liquid in the second condensing device, and uses the second working fluid driving device to enter the fourth heat exchange device again to start the heat exchange cycle.

[0043] Preferably, the heat exchange medium in step (2) includes water, and the heated water can be used for heating or as domestic water.

[0044] As a preferred technical solution of the present invention, the energy utilization method specifically comprises the following steps:

[0045] (1) After air enters the compressor of the methanol gas turbine power generation module and is compressed, it is burned in the combustion chamber with the methanol heated by the methanol preheating module to generate fuel gas to drive the first turbine to do work and drive the first generator to generate first electrical energy. The first high-temperature flue gas discharged by the first turbine enters the first heat exchange device of the methanol preheating module to heat the methanol.

[0046] The first organic working fluid exchanges heat with the first high-temperature flue gas from the first heat exchange device in the second heat exchange device in the ORC power generation module to form the first steam, the first steam enters the second turbine to expand and do work, and drives the second generator to generate second electric energy, the steam exhausted from the second turbine condenses into liquid in the first condensing device, and enters the second heat exchange device again through the first working fluid driving device to start the heat exchange cycle;

[0047] (2) The first electric energy and the second electric energy are both supplied to the electrolytic cell of the aluminum electrolysis module to electrolyze aluminum; the exhaust gas at the outlet of the electrolytic cell enters the third heat exchange device of the waste heat utilization module to exchange heat with water;

[0048] Or the exhaust gas at the outlet of the electrolyzer enters the fourth heat exchange device of the waste heat power generation utilization module to exchange heat with the second organic working fluid. The second organic working fluid is heated to form a second steam. The second steam enters the third turbine to expand and do work, and drives the third generator to generate electricity. The steam exhausted from the third turbine is condensed into a liquid in the second condensing device, and uses the second working fluid driving device to enter the fourth heat exchange device again to start the heat exchange cycle.

[0049] Compared with the prior art, the present invention has at least the following beneficial effects:

[0050] (1) The methanol gas turbine and ORC coupled aluminum electrolysis energy utilization device system provided by the present invention realizes the comprehensive utilization of the high-temperature exhaust gas waste heat discharged from the methanol gas turbine power generation module and the aluminum electrolysis module, achieving the effect of energy saving and consumption reduction;

[0051] (2) The aluminum electrolysis flue gas waste heat utilization module in the energy utilization device system of the methanol gas turbine and ORC coupled to the aluminum electrolysis provided by the present invention reduces the temperature of the high-temperature flue gas at the outlet of the electrolytic cell, which is beneficial to prolonging the service life of the bags in the subsequent dust removal system;

[0052] (3) The methanol gas turbine and ORC coupled electrolytic aluminum energy utilization device system provided by the present invention uses green methanol as fuel for gas turbine power generation, which meets the electrolytic aluminum industry's development needs for green and low-carbon development, is beneficial to the deep decarbonization of the aluminum industry, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A schematic diagram of an energy utilization system for electrolytic aluminum coupled with a methanol gas turbine and ORC provided in a specific embodiment of the present invention.

[0054] Figure 2 A schematic diagram of a methanol gas engine power generation module provided for a specific embodiment of the present invention.

[0055] Figure 3 A schematic diagram of a methanol preheating module provided in a specific embodiment of the present invention.

[0056] Figure 4 A schematic diagram of an ORC power generation module provided in a specific embodiment of the present invention.

[0057] Figure 5 A schematic diagram of a waste heat utilization module in an electrolytic aluminum fume waste heat utilization module provided in a specific embodiment of the present invention.

[0058] Figure 6 A schematic diagram of a waste heat power generation utilization module in an aluminum electrolytic fume waste heat utilization module provided in a specific embodiment of the present invention.

[0059] Figure 7 5%, 15%, 20% and 30% of the electrolytic cells are selected for matching calculation in the specific implementation mode of the present invention, and the relationship between the system cycle output and the total system efficiency is shown in the figure.

[0060] In the figure: 1-methanol gas turbine power generation module; 2-methanol preheating module; 3-ORC power generation module; 4-electrolytic aluminum module; 5-electrolytic aluminum flue gas waste heat utilization module; 6-waste heat utilization module; 7-waste heat power generation utilization module; 8-compressor; 9-combustion chamber; 10-first turbine; 11-first generator; 12-first heat exchange device; 13-second heat exchange device; 14-second turbine; 15-second generator; 16-first condensing device; 17-first working fluid driving device; 18-third heat exchange device; 19-fourth heat exchange device; 20-third turbine; 21-third generator; 22-second condensing device; 23-second working fluid driving device. DETAILED DESCRIPTION

[0061] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0062] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0063] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0064] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0065] Those skilled in the art should understand that the present invention necessarily includes necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main inventive point of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0066] As a specific embodiment of the present invention, a methanol gas turbine and ORC coupled electrolytic aluminum energy utilization device system is provided, and its schematic diagram is as follows: Figure 1 shown.

[0067] The energy utilization device system includes a methanol gas engine power generation module 1, a methanol preheating module 2, an ORC power generation module 3, an electrolytic aluminum module 4 and an electrolytic aluminum flue gas waste heat utilization module 5;

[0068] The methanol gas engine power generation module 1, the methanol preheating module 2 and the ORC power generation module 3 are connected in sequence; the methanol gas engine power generation module 1 and the ORC power generation module 3 are both connected to the electrolytic aluminum module 4; the electrolytic aluminum module 4 is connected to the electrolytic aluminum flue gas waste heat utilization module 5.

[0069] The methanol gas engine power generation module 1 includes a compressor 8, a combustion chamber 9, a first turbine 10 and a first generator 11 connected in sequence, and its schematic diagram is shown as follows Figure 2 shown.

[0070] The compressor 8 is coaxially connected to the first turbine 10;

[0071] The methanol preheating module 2 includes a first heat exchange device 12, and its schematic diagram is as shown in Figure 3 shown.

[0072] The first heat exchange device 12 is connected to the first turbine 10 via a first flue gas input pipe;

[0073] The first heat exchange device 12 is connected to the methanol fuel input pipeline;

[0074] The first heat exchange device 12 is connected to the combustion chamber 9 via a methanol fuel output pipeline.

[0075] The ORC power generation module 3 includes a second heat exchange device 13, a second turbine 14, a first condensing device 16 and a first working medium driving device 17 which are cyclically connected. Figure 4 shown.

[0076] The second heat exchange device 13 in the ORC power generation module 3 is connected to the first heat exchange device 12 via the first flue gas exhaust pipe;

[0077] The ORC power generation module 3 further includes a second generator 15;

[0078] The second generator 15 is coaxially connected to the second turbine 14 .

[0079] The aluminum electrolysis module 4 includes an electrolytic cell.

[0080] The aluminum electrolytic fume waste heat utilization module 5 includes a waste heat thermal utilization module 6 or a waste heat power generation utilization module 7 .

[0081] The waste heat utilization module 6 includes a third heat exchange device 18, a schematic diagram of which is shown in FIG. Figure 5 shown.

[0082] The third heat exchange device 18 is connected to the electrolytic cell via the second flue gas input pipeline;

[0083] The third heat exchange device 18 is connected to the heat exchange medium input pipeline and the heat exchange medium output pipeline respectively.

[0084] The waste heat power generation module 7 includes a fourth heat exchange device 19, a third turbine 20, a second condensing device 22 and a second working medium driving device 23 which are connected in a circular manner. Figure 6 shown.

[0085] The fourth heat exchange device 19 in the waste heat power generation module 7 is connected to the electrolytic cell via the second flue gas input pipeline;

[0086] The waste heat power generation module 7 further includes a third generator 21;

[0087] The third generator 21 is coaxially connected to the third turbine 20 .

[0088] As a specific embodiment of the present invention, a method for energy utilization of a methanol gas turbine and ORC coupled to electrolytic aluminum is also provided. The energy utilization method is performed using the above-mentioned methanol gas turbine and ORC coupled to electrolytic aluminum energy utilization device system; the energy utilization method comprises the following steps:

[0089] (1) After air enters the compressor 8 of the methanol gas turbine power generation module 1 and is compressed, it is burned in the combustion chamber 9 with the methanol heated by the methanol preheating module 2 to generate fuel gas to drive the first turbine 10 to do work and drive the first generator 11 to generate first electrical energy. The first high-temperature flue gas discharged by the first turbine 10 enters the first heat exchange device 12 of the methanol preheating module 2 to heat the methanol.

[0090] The first organic working fluid exchanges heat with the first high-temperature flue gas from the first heat exchange device 12 in the second heat exchange device 13 in the ORC power generation module 3 to form first steam. The first steam enters the second turbine 14 to expand and do work, and drives the second generator 15 to generate second electric energy. The steam exhausted from the second turbine 14 condenses into liquid in the first condensing device 16, and enters the second heat exchange device 13 again through the first working fluid driving device 17 to start a heat exchange cycle.

[0091] (2) The first electric energy and the second electric energy are both supplied to the electrolytic cell of the aluminum electrolysis module 4 to perform aluminum electrolysis; the exhaust gas at the outlet of the electrolytic cell enters the third heat exchange device 18 of the waste heat utilization module 6 to perform heat exchange with water;

[0092] Or the exhaust gas at the outlet of the electrolyzer enters the fourth heat exchange device 19 of the waste heat power generation utilization module 7 to exchange heat with the second organic working fluid. The second organic working fluid is heated to form a second steam. The second steam enters the third turbine 20 to expand and do work, and drives the third generator 21 to generate electricity. The steam exhausted from the third turbine 20 is condensed into a liquid in the second condensing device 22, and uses the second working fluid driving device 23 to enter the fourth heat exchange device 19 again to start the heat exchange cycle.

[0093] The above specific implementation does not take into account the heat exchange loss and leakage loss of air in different devices and sections of pipelines;

[0094] The isentropic efficiency of compressor 8 is 89% and the mechanical efficiency is 99%;

[0095] The pressure loss coefficient of the combustion chamber 9 is 4%, and the combustion efficiency (due to heat energy loss) is 99%;

[0096] The first turbine 10 has an isentropic efficiency of 90% and a mechanical efficiency of 99%;

[0097] The end difference of each section of the first heat exchanger 12, the second heat exchanger 13, the third heat exchanger 18, and the fourth heat exchanger 19 shall not be less than 10°C to maintain normal heat exchange;

[0098] The efficiency of the first generator 11, the second generator 15 and the third generator 21 are all 98.4%;

[0099] The isentropic efficiency of the second turbine 14 and the third turbine 20 is 88%, and the mechanical efficiency is 99.8%;

[0100] The isentropic efficiency of the first working medium driving device 17 and the second working medium driving device 23 is 80%, and the mechanical efficiency is 99.8%.

[0101] In this specific implementation, a typical electrolytic aluminum enterprise is taken as an example. Its 400kA series current intensity is 373.4kA, 288 electrolytic cells are in operation, and the average voltage of a single cell is 4.040V. Initially, 5% of the electrolytic cells are selected for matching calculation. The main parameters on the 4 side of the electrolytic aluminum module are shown in Table 1.

[0102] Table 1

[0103] parameter unit Numeric Electrolyzer tower 14 Electrolyzer power MW / unit 1.51 Flue gas volume of electrolyzer <![CDATA[NM 3 / h / station]]> 9000 Flue gas temperature ℃ 80-125 Smoke density <![CDATA[kg / NM 3 ]]> 1.295 Flue gas specific heat kJ / kg·℃ 1.062

[0104] The relevant performance parameters of the methanol gas engine power generation module 1 and the ORC power generation module 3 are shown in Table 2.

[0105] Table 2

[0106]

[0107]

[0108] 5%, 15%, 20% and 30% of the electrolytic cells are selected for matching calculation. The relationship between the system cycle output and the total system efficiency is as follows: Figure 7 As shown. Figure 7 It can be seen that as the number of electrolyzers increases, the required system cycle output increases and the overall system efficiency also increases.

[0109] The relevant performance parameters of the aluminum electrolytic fume waste heat utilization module 5 when using the waste heat thermal utilization module 6 or the waste heat power generation utilization module 7 are shown in Table 3 and Table 4 respectively.

[0110] Table 3

[0111] parameter unit Numeric Flue gas side temperature ℃ 100 / 80 Heat retention coefficient ％ 94 Water side temperature ℃ 70 / 55 Heat recovery kw 905

[0112] Table 4

[0113] parameter unit Numeric Total flue gas volume of electrolyzer <![CDATA[NM 3 / h]]> 126000 ORC contributes kw 90.5

[0114] The present invention uses the high-temperature flue gas discharged by the first turbine for preheating methanol fuel and ORC power generation, and the power generation efficiency of the entire system is increased from 41.9% to 51.09%; the exhaust gas discharged by the electrolytic aluminum module is used for comprehensive utilization of waste heat, which has the effect of energy saving and consumption reduction; green methanol is used as fuel for power generation to meet the development needs of the electrolytic aluminum industry for green and low-carbon development. The utilization hours of the electrolytic cell are taken as 8,000 hours. Compared with coal-fired power generation, it is equivalent to saving 27,500 tons of standard coal per year, reducing CO2 emissions by 77,100 tons, SO2 emissions by about 452.3 tons, and NOx emissions by about 102.5 tons each year.

[0115] The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed structural features, that is, it does not mean that the present invention must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0116] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A methanol gas turbine and ORC coupled aluminum electrolysis energy utilization device system, characterized in that: The energy utilization device system includes a methanol gas engine power generation module, a methanol preheating module, an ORC power generation module, an electrolytic aluminum module and an electrolytic aluminum flue gas waste heat utilization module; The methanol gas engine power generation module, the methanol preheating module and the ORC power generation module are connected in sequence; the methanol gas engine power generation module and the ORC power generation module are both connected to the electrolytic aluminum module; the electrolytic aluminum module is connected to the electrolytic aluminum flue gas waste heat utilization module.

2. The energy utilization device system according to claim 1, characterized in that: The methanol gas engine power generation module comprises a compressor, a combustion chamber, a first turbine and a first generator connected in sequence; Preferably, the compressor is coaxially connected to the first turbine; Preferably, the methanol preheating module comprises a first heat exchange device; Preferably, the first heat exchange device is connected to the first turbine via a first flue gas input duct; Preferably, the first heat exchange device is connected to a methanol fuel input pipeline; Preferably, the first heat exchange device is connected to the combustion chamber via a methanol fuel output pipeline.

3. The energy utilization device system according to claim 1 or 2, characterized in that: The ORC power generation module includes a second heat exchange device, a second turbine, a first condensing device and a first working medium driving device which are cyclically connected; Preferably, the second heat exchange device in the ORC power generation module is connected to the first heat exchange device via the first flue gas exhaust duct; Preferably, the ORC power generation module further comprises a second generator; Preferably, the second generator is coaxially connected to the second turbine.

4. The energy utilization device system according to any one of claims 1 to 3, characterized in that: The aluminum electrolysis module includes an electrolytic cell.

5. The energy utilization device system according to any one of claims 1 to 4, characterized in that: The aluminum electrolytic fume waste heat utilization module includes a waste heat thermal utilization module or a waste heat power generation utilization module.

6. The energy utilization device system according to claim 5, characterized in that: The waste heat utilization module includes a third heat exchange device; Preferably, the third heat exchange device is connected to the electrolytic cell via a second flue gas input pipe; Preferably, the third heat exchange device is connected to the heat exchange medium input pipeline and the heat exchange medium output pipeline respectively.

7. The energy utilization device system according to claim 5, characterized in that: The waste heat power generation module comprises a fourth heat exchange device, a third turbine, a second condensing device and a second working medium driving device which are cyclically connected; Preferably, the fourth heat exchange device in the waste heat power generation module is connected to the electrolytic cell via the second flue gas input pipeline; Preferably, the waste heat power generation module further includes a third generator; Preferably, the third generator is coaxially connected to the third turbine.

8. A method for utilizing energy by coupling a methanol gas turbine and ORC to electrolyze aluminum, characterized in that: The energy utilization method is carried out by using the methanol gas turbine and ORC coupled electrolytic aluminum energy utilization device system according to any one of claims 1 to 7; the energy utilization method comprises the following steps: (1) The methanol gas engine power generation module generates electricity to generate first electrical energy and generates first high-temperature flue gas; the first high-temperature flue gas enters the methanol preheating module to heat methanol, and then enters the ORC power generation module to generate electricity to generate second electrical energy; wherein the heated methanol enters the methanol gas engine power generation module to generate electricity; (2) The first electric energy and the second electric energy are both supplied to the aluminum electrolysis module to perform aluminum electrolysis and simultaneously generate a second high-temperature flue gas; (3) The second high-temperature flue gas enters the electrolytic aluminum flue gas waste heat utilization module for recycling.

9. The energy utilization method according to claim 8, characterized in that: The energy utilization method specifically comprises the following steps: (1) After air enters the compressor of the methanol gas turbine power generation module and is compressed, it is burned in the combustion chamber with the methanol heated by the methanol preheating module to generate fuel gas to drive the first turbine to do work and drive the first generator to generate first electrical energy. The first high-temperature flue gas discharged by the first turbine enters the first heat exchange device of the methanol preheating module to heat the methanol. The first organic working fluid exchanges heat with the first high-temperature flue gas from the first heat exchange device in the second heat exchange device in the ORC power generation module to form the first steam, the first steam enters the second turbine to expand and do work, and drives the second generator to generate second electric energy, the steam exhausted from the second turbine condenses into liquid in the first condensing device, and enters the second heat exchange device again through the first working fluid driving device to start the heat exchange cycle; (2) The first electric energy and the second electric energy are both supplied to the electrolytic cell of the aluminum electrolysis module to electrolyze aluminum; the exhaust gas at the outlet of the electrolytic cell enters the third heat exchange device of the waste heat utilization module to exchange heat with the heat exchange medium; Or the exhaust gas at the outlet of the electrolyzer enters the fourth heat exchange device of the waste heat power generation utilization module to exchange heat with the second organic working fluid. The second organic working fluid is heated to form a second steam. The second steam enters the third turbine to expand and do work, and drives the third generator to generate electricity. The steam exhausted from the third turbine is condensed into a liquid in the second condensing device, and uses the second working fluid driving device to enter the fourth heat exchange device again to start the heat exchange cycle.

10. The energy utilization method according to claim 9, characterized in that: The heat exchange medium in step (2) includes water.

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