CN108301922A - Mixing energy supplying system based on gas turbine and molten carbonate fuel cell - Google Patents

Abstract

The invention relates to a hybrid energy supply system based on gas turbines and molten carbonate fuel cells, and belongs to the field of distributed energy supply systems. The system includes air separator, combustion chamber, gas turbine, VM cycle heat pump and other components. H ₂ and O ₂ respectively react at the anode and cathode of the molten carbonate fuel cell to generate electricity. At the same time, the high-temperature gas generated by the oxygen-rich combustion in the combustion chamber enters the gas turbine to expand and perform work, and the generator generates electricity; The VM cycle heat pump provides cooling to users in summer, heat to users in winter, and provides users with domestic hot water load throughout the year. This hybrid energy supply system can not only guarantee the system's demand for electricity, cooling, and heating energy, but also has the characteristics of high power generation efficiency, diverse fuel choices, energy saving and environmental protection.

Description

Hybrid energy supply system based on gas turbine and molten carbonate fuel cell

technical field

The invention belongs to the field of distributed energy supply systems, in particular to a hybrid energy supply system based on gas turbines and molten carbonate fuel cells.

Background technique

Molten carbonate fuel cell is a high-temperature fuel cell using molten carbonate as an oxygen ion conductor. It is usually called a second-generation fuel cell, and its working temperature is around 973-923K. Compared with low-temperature fuel cells, at the working temperature of molten carbonate fuel cells, fuel (such as natural gas) can be converted directly inside the battery, which not only reduces the cost, but also improves efficiency; secondly, the high-temperature waste heat of the battery reaction can be used It can be used in industrial processing or boiler cycle; finally, the CO produced by fuel conversion will not poison the fuel cell electrode catalyst, but can be used as fuel for molten carbonate fuel cells.

However, molten carbonate fuel cells have a significant disadvantage of requiring a constant supply of _CO2 to the cathode. The conventional practice is to retransmit the CO ₂ released from the anode to the cathode, but this also increases the complexity of the system structure.

At present, the gas turbine driven by natural gas is the most common thermoelectric conversion device, but the gas turbine is affected by the Carnot cycle limitation and combustion loss, and the power generation efficiency of the system still needs to be improved.

Therefore, considering the combination of the common thermoelectric conversion device and the molten carbonate fuel cell, it can not only make full use of the raw materials and products of the molten carbonate fuel cell power generation process, realize the oxygen-enriched combustion in the combustion chamber, but also use the products of the combustion chamber The CO ₂ in the molten carbonate fuel cell guarantees the CO ₂ content of the cathode, thereby improving the power generation efficiency and fuel utilization of the entire system.

At the same time, the exhaust gas temperature of the gas turbine is as high as 600°C, and direct discharge will cause energy waste. In order to use this part of the heat in steps, a VM cycle heat pump is selected as the cold and heat production equipment.

Contents of the invention

In view of the above existing problems and phenomena, the present invention provides a hybrid energy supply system based on gas turbines and molten carbonate fuel cells, aiming to meet the energy demand of users through the hybrid distributed system, and recycle the remaining heat to achieve more Good energy cascade utilization mode.

In order to achieve the above object, the technical scheme that the present invention takes is:

Hybrid energy supply systems based on gas turbines and molten carbonate fuel cells, including:

Compressor: configured to compress air;

air separator: configured to separate air;

Converter: configured to convert the fuel into the reactants required for the molten carbonate fuel cell;

Molten carbonate fuel cell anode: configured to undergo a reduction reaction;

Molten Carbonate Fuel Cell Cathode: configured for mode oxidation reactions;

Combustor: It is configured to reburn the remaining fuel in the anode exhaust of the molten carbonate fuel cell and perform oxygen-enriched combustion to further increase the exhaust temperature of the combustion chamber;

Gas turbines: configured to convert thermal energy of high temperature gases into mechanical energy;

Generator: configured to convert mechanical energy into electrical energy to produce the required electricity;

VM cycle heat pump: It is configured to transfer the low-temperature heat source of steam to the high-temperature heat source for cooling and heating to meet the energy demand of users;

Heat exchanger I: it is configured to transfer the heat of the hot fluid in the heat chamber of the VM cycle heat pump to the cold fluid;

Heat exchanger II: It is configured to transfer the heat of the hot fluid in the chamber of the VM cycle heat pump to the cold fluid;

Heat exchanger III: It is configured to transfer the cooling capacity of the cold fluid in the cold chamber of the VM cycle heat pump to the hot fluid.

In the aforementioned hybrid energy supply system based on a gas turbine and a molten carbonate fuel cell, the products of the air separator are O ₂ and N ₂ products.

In the aforementioned hybrid energy supply system based on a gas turbine and a molten carbonate fuel cell, the products of the reformer are CO and H2.

The above-mentioned hybrid energy supply system based on a gas turbine and a molten carbonate fuel cell, wherein the reactants in the anode of the molten carbonate fuel cell are H ₂ and CO ₃ ^2- , and the products are H ₂ O and CO ₂ .

In the aforementioned hybrid energy supply system based on a gas turbine and a molten carbonate fuel cell, the reactants in the cathode of the molten carbonate fuel cell are O ₂ and CO ₂ , and the product is CO ₃ ²⁻ .

In the aforementioned hybrid energy supply system based on a gas turbine and a molten carbonate fuel cell, a part of the flue gas generated by the gas turbine enters the combustion chamber, and the other part enters the converter.

In the above-mentioned hybrid energy supply system based on gas turbine and molten carbonate fuel cell, the VM cycle heat pump supplies the domestic hot water load through the hot cavity, supplies the cooling capacity required by users through the cold cavity, and supplies heat through the room temperature cavity.

The above-mentioned hybrid energy supply system based on gas turbine and molten carbonate fuel cell, wherein, the heat exchanger I is connected with the heat chamber of the VM cycle heat pump and operates throughout the year.

In the aforementioned hybrid energy supply system based on gas turbines and molten carbonate fuel cells, the heat exchanger II is connected to the chamber of the VM cycle heat pump at room temperature, and operates in winter and stops in summer.

In the aforementioned hybrid energy supply system based on gas turbines and molten carbonate fuel cells, the heat exchanger III is connected to the cold chamber of the VM cycle heat pump, and operates in summer and stops in winter.

The above technical solution has the following advantages or beneficial effects:

1. Molten carbonate fuel cell has a high working temperature and low activation energy of electrode reaction. It does not require precious metals as catalysts for hydrogen oxidation or oxygen reduction, which reduces the cost of power generation of the system.

2. The CO ₂ product obtained by the oxygen-enriched combustion in the combustion chamber is directly passed into the cathode of the molten carbonate fuel cell as a reactant to participate in the reaction, which not only reduces the emission of carbon oxides, but also ensures the continuous operation of the molten carbonate fuel cell.

3. After the exhaust gas from the gas turbine is passed into the converter and the combustion chamber for heat recovery, the VM cycle heat pump is finally driven to work. This method of flue gas utilization can not only ensure the energy demand at all levels, but also save energy.

Description of drawings

The invention and its characteristics, configurations and advantages will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings. Like numbers designate like parts throughout the drawings. The drawings are not intended to be drawn to scale, emphasis instead being placed upon illustrating the gist of the invention.

Figure 1. Schematic diagram of the hybrid energy supply system based on gas turbine and molten carbonate fuel cell

Figure 2. Working principle diagram of molten carbonate fuel cell

The meanings of the symbols in the figure are as follows: 1-compressor; 2-air separator; 3-converter; 4-molten carbonate fuel cell anode; 5-molten carbonate fuel cell cathode; 6-combustion chamber; Gas turbine; 8-generator; 9-VM cycle heat pump; 10-heat exchanger I; 11-heat exchanger II; 12-heat exchanger III;

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but not as a limitation of the present invention.

The working principle of the VM cycle heat pump refers to the Chinese patent CN101865566A.

As shown in Figure 1, the system includes: compressor 1, air separator 2, converter 3, molten carbonate fuel cell anode 4, molten carbonate fuel cell cathode 5, combustion chamber 6, gas turbine 7, generator 8. VM cycle heat pump 9, heat exchanger I 10, heat exchanger II 11, heat exchanger III 12. The air compressed by the compressor 1 enters the air separator 2 for gas separation to obtain _O2 and _N2 products, a part of _O2 enters the cathode 5 of the molten carbonate fuel cell, and the other part of _O2 enters the combustion chamber 6; the fuel is converted The H ₂ obtained after conversion by the device 3 enters the anode 4 of the molten carbonate fuel cell, and undergoes an electrochemical reaction with O ₂ to generate electricity; at the same time, fuel, CO, O ₂ , flue gas and the remaining fuel in the anode exhaust are discharged in the combustion chamber 6 mixing, the high-temperature flue gas produced by oxygen-enriched combustion is sent to the gas turbine 7 to expand and perform work, and the generator 8 is used to generate electricity; the flue gas from the gas turbine 7 is then used to drive the VM cycle heat pump 9, and heat is supplied to users through the heat exchanger II 11 in winter. In summer, the heat exchanger III 12 absorbs heat from the outside for cooling, and the heat exchanger I 10 supplies domestic hot water throughout the year.

The working principle of the molten carbonate fuel cell will be introduced below in conjunction with FIG. 2 .

In Fig. 2, the structure of the molten carbonate fuel cell mainly includes an upper separator, a lower separator, an anode 4 of a molten carbonate fuel cell, a cathode 5 of a molten carbonate fuel cell and an electrolyte plate. O ₂ and CO ₂ undergo oxidation reaction with electrons at the cathode to produce CO ₃ ^2- , CO ₃ ^2- in the electrolyte plate moves directly from the cathode to the anode; H ₂ in the fuel reacts with CO ₃ ^2- at the anode to produce CO ₂ , H ₂ O and electrons, and the electrons are collected by the collector plate and then reach the partition; finally, they are connected to the load device through the upper and lower partitions to form a complete circuit including electron transmission and ion movement.

Those skilled in the art should understand that those skilled in the art can implement the variation examples in combination with the prior art and the foregoing embodiments, which will not be repeated here. Such variations do not affect the essence of the present invention, and will not be repeated here.

The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; Many possible changes and modifications are made in the technical solution of the invention, or modified into equivalent embodiments with equivalent changes, which do not affect the essence of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, which do not deviate from the technical solution of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims (3)

1. the mixing energy supplying system based on gas turbine and molten carbonate fuel cell, it is characterised in that：It include compressor, Air separator, converter, fused carbonate fuel battery anode, fused carbonate fuel battery cathode, combustion chamber, combustion gas wheel Machine, generator, VM circulating heat pumps, heat exchanger I, heat exchanger II, heat exchanger III；The VM circulating heat pumps include hot chamber, room temperature Chamber, cold chamber；

Enter air separator by the compressed air of compressor and carry out gas separation, obtains O₂And N₂Product, a part of O₂Into Enter cathode, another part O₂Into combustion chamber；Fuel obtains H by converter₂, H₂Into anode and O₂It reacts Electricity；Meanwhile fuel, O₂, the residual fuel in flue gas and anode exhaust be mixed and burned in combustion chamber, the high-temperature gas of generation into Enter gas turbine expansion work, and makes electrical power generators；Meanwhile driving VM circulating heat pumps, summer logical using gas turbine flue gas Supercooling chamber absorbs heat from the external world and freezes, and winter is heated by room temperature chamber to user, the hot annual domestic hot-water of chamber supply.

2. the mixing energy supplying system based on gas turbine and molten carbonate fuel cell as described in claim 1, feature It is, the driving heat source temperature of the VM circulating heat pumps is in the range of 800-900K.

3. the mixing energy supplying system based on gas turbine and molten carbonate fuel cell as described in claim 1, feature It is, the O of oxygen-enriched combusting in the combustion chamber₂Concentration controls between 27-39%.