Fuel cell system

Abstract

The invention discloses a fuel cell system, relates to the technical field of fuel cells, and aims to effectively improve the whole-process fuel utilization rate of fuel gas and improve the power generation efficiency. The fuel cell system includes a fuel cell assembly; an anode heat exchanger comprising a first port, a second port, a third port and a fourth port, wherein the first port is communicated with the second port, the third port is communicated with the fourth port, the first port is used for passing through of fuel gas, the second port is communicated with the anode gas inlet of thefuel cell assembly, the third port is communicated with the anode gas outlet of a fuel cell, and the fourth port is respectively communicated with the first port through a first shunt pipe and a second shunt pipe; and a decarburization and dehydration device, wherein the inlet end of the decarburization and dehydration device is communicated with the second shunt pipe, and the outlet end of the decarburization and dehydration device is communicated with the first port. The fuel cell system is used for improving the working performance of the cell.

Description

technical field [0001] The invention relates to the technical field of fuel cells, in particular to a fuel cell system. Background technique [0002] Solid oxide fuel cells use relatively cheap hydrocarbons such as natural gas and coal-combusted synthesis gas as fuel gases to provide hydrogen sources, use air as oxygen sources, and hydrocarbons are reformed upstream of fuel cell components . [0003] The single-pass fuel utilization rate of the existing solid oxide fuel cell (the single-pass fuel utilization rate refers to the fuel gas entering the battery from the anode inlet and burning, and then exhausting the tail gas from the anode gas outlet. In this process, the fuel gas utilization rate) Generally, it will not exceed 85%, so the exhaust gas discharged from the battery anode outlet will contain some unused fuel gas (the main components are CO, H 2 ), in order to fully recover the calorific value of this part of the gas, the tail gas cycle can be set to improve the f...

AI Technical Summary

Problems solved by technology

When the temperature of the absorption tank is greater than or equal to 60 degrees, close the valve to maintain the temperature of the absorption tank, and the fuel exhaust gas removes CO in the absorption tank 2 After that, it enters the fuel cell together with fresh fuel gas for anode reaction. Although the device effectively removes CO 2 , to avoid the phenomenon of diluting the combustible gas concentration, but there are also the following technical problems: 1. the working temperature of the absorption tank is about 60 ℃, the working temperature of the fuel cell is about 700-800 ℃, and the outlet high temperature tail gas of the fuel cell ( About 800℃) must be cooled and then enter the absorption tank. The device uses the heat dissipation pipeline to dissipate heat from the high-temperature exhaust gas, causing serious loss of heat, and the heat is not fully utilized

At the same time, after the decarbonized tail gas is mixed with fresh fuel gas, it needs to be preheated and enters the fuel cell. The device is not equipped with any internal heat recovery device, and an external heat source (such as electric heating) needs to be introduced. Generally speaking, although the power generated by the fuel cell is limited However, due to the introduction of the low-temperature absorption tank, the power generation efficiency of the entire fuel cell is not greatly improved, but may decrease; 2. The device also ignores the water-to-carbon ratio at the fuel cell inlet (calculated by the ratio of oxygen atoms to carbon atoms) regulation, containing CO, CH 4 When the hydrocarbon fuel enters the fuel cell, there will be the possibility of coking. Generally, the water-to-carbon ratio of the imported gas should not be lower than 2.0. Otherwise, additional water vapor will be added to the battery. The additional water vapor will take away part of the battery heat and thus Affecting the power generation efficiency of the battery, the desulfurization and decarbonization agent in the absorption tank of the device is removing CO 2 At the same time, the water vapor will be removed and recycled back to the fuel cell. The water-to-carbon ratio is far from enough, so additional water vapor needs to be introduced, which will reduce the power generation efficiency

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