TECHNICAL FIELD

The present invention relates to the technical field of SOFC systems, particularly to an SOFC gas line and an SOFC system vehicle.

BACKGROUND ART

In an SOFC (Solid Oxide Fuel Cell) fuel gas system, fuel gas is supplied to stack hot box in two channels: one channel is to an exhaust burner; and the other is to a reformer. The fuel gas generally is CNG (Compressed Natural Gas). The flows of the two channels of gas need to be accurately controlled by mass flow controllers (MFC). Due to different requirements for gas flows in the two channels, two ranges of MFCs are used in the gas system. When the MFC works normally, the front-end inlet gas pressure is about 5 bars and the outlet pressure is about 150 mbar.

Fig. 1 is a structural schematic view of an SOFC fuel gas control branch.

In the SOFC gas line, behind a solenoid valve T is a tee pipe, and behind the tee pipe are two mass flow controllers MFC 2 ^' and MFC 3 ^' connected in parallel. The role of the solenoid valveT is to cut off the gas in the gas line in time and protect the MFCs. The MFCs can not only control the gas flow but also cut off the gas line.

When the MFCs and the solenoid valveT are powered off, the MFCs will lag accordingly. Consequently, after the solenoid valveT cuts off the gas in the line, the gas will continue to leak from the rear ends of the MFCs, resulting in loss of gas sealed between the solenoid valve T and the MFC 2 ^' / MFC3 ^' . The lines between the MFC 27 MFC 3 ^' and the solenoid valve T are short and a very small amount of gas is sealed. The lag of the MFC 2 ^' and the MFC 3 ^' and the leakage of the solenoid valve T will result in pressure reduction in this section.

After the front-end pressure of the MFC 2 ^' and the MFC 3 ^' is reduced to smaller than or equal to 2.6 bars, if the solenoid valve T is powered on again, the pressure of the gas in this section will rise to 5 bars quickly. For reason of the own structure of the MFC 2 ^' and the MFC 3 ^' , the sudden change of the pressure will cause sudden opening of the MFC 2 ^' and the MFC 3 ^' , thereby making the gas enter an exhaust burner and a reformer from the mass flow controllers.

If this change happens during hot start, the fuel gas will enter a stack via the reformer. At high temperature, it is highly likely to cause carbon deposits in the stack, thereby damaging the stack.

Therefore, how to prevent the fuel gas in the SOFC fuel gas system from entering the reformer is a problem.

SUMMARY OF THE INVENTION

The present invention provides an SOFC gas line to avoid the fuel gas in the SOFC fuel gas system entering a reformer; and the present invention further provides an SOFC system vehicle.

A first aspect of the invention provides an SOFC gas line, comprising a main line supplying gas to a stack hot box, and an exhaust burner branch and a reformer branch communicated with the main line. A solenoid valve is arranged on the main line, and a first MFC and a second MFC are arranged on the exhaust burner branch and the reformer branch respectively. The main line is located at a gas outlet of the solenoid and further provided with a pressure stabilizer, which increases the gas flow volume and stabilizes pressure in the main line.

The pressure stabilizer can be internally provided with a gas flow storage area communicated with the main line, the exhaust burner branch and the reformer branch, and storing the gas flow in the main line.

The pressure stabilizer can comprise a gas flow filter unit, which removes impurities from the gas flow in the main line.

A second aspect of the invention provides an SOFC system vehicle, comprising a vehicle body and a stack hot box arranged inside the vehicle body, and further comprising an SOFC gas line communicated with the stack hot box, wherein the SOFC gas line is the SOFC gas line in accordance with the first aspect.

The SOFC gas line provided by the present invention comprises a main line supplying gas to a stack hot box, and an exhaust burner branch and a reformer branch communicated with the main line; a solenoid valve is arranged on the main line, and a first MFC and a second MFC are arranged on the exhaust burner branch and the reformer branch respectively; the main line is located at the gas outlet of the solenoid valve and further provided with a pressure stabilizer for stabilizing the gas pressure in the main line. The fuel gas in the SOFC system enters the exhaust burner branch and the reformer branch via the main line respectively, the solenoid valve adjusts the connection and disconnection of the main line, the first MFC and the second MFC adjust the gas communication of the two branches respectively, and a pressure stabilizer is further arranged on the main line and increases the gas flow volume and stabilizes the pressure in the main line. The pressure stabilizer increases the gas flow in the main line. During hot start, the pressure stabilizer stabilizes the gas pressure in the line, avoids fuel gas entering the first MFC or second MFC due to pressure change of the gas flow between the main line and branches during secondary power-on of the solenoid valve, causing carbon deposits in the stack, and reduces stack hazard.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings used in the description of the embodiments will be briefly described below. The drawings in the description below are just some embodiments of the present invention.

Fig. 1 is a structural schematic view of an SOFC fuel gas control branch.

Fig. 2 is a structural schematic view of an SOFC gas line according to an embodiment of the present invention.

DETAILED DESCRIPTION

The present invention discloses an SOFC gas line to avoid the fuel gas in the SOFC fuel gas system entering a reformer; and the present invention further provides an SOFC system vehicle.

The described embodiments are only some, not all of the embodiments of the present invention.

Fig. 2 is a structural schematic view of an embodiment of an SOFC gas line provided by the present invention. The SOFC gas line comprises a main line 10 supplying gas to a stack hot box, and an exhaust burner branch 11 and a reformer branch 12 communicated with the main line 10. A solenoid valve 1 is arranged on the main line 10, and a first MFC 2 and a second MFC 3 are arranged on the exhaust burner branch 11 and the reformer branch 12 respectively. The main line 10 is located at a gas outlet of the solenoid valve 1 and further provided with a pressure stabilizer 4 for stabilizing the gas pressure in the main line 10. The fuel gas in the SOFC system enters the exhaust burner branch 11 and the reformer branch 12 via the main line 10 respectively, the solenoid valve 1 adjusts the connection and disconnection of the main line 10, the first MFC 2 and the second MFC 3 adjust the gas communication of the two branches respectively, and a pressure stabilizer 4 is further arranged on the main line 10 and increases the gas flow volume and stabilizes the pressure in the main line 10. During hot start, the pressure stabilizer 4 stabilizes the gas pressure in the line, avoids fuel gas entering the first MFC 2 or the second MFC 3 due to pressure change of the gas flow between the main line 10 and branches during secondary power-on of the solenoid valve 1, causing carbon deposits in the stack, and reduces stack hazard.

The pressure stabilizer 4 increases the gas flow contained in the main line 1. When the main line 10, the exhaust burner branch 11 and the reformer branch 12 supply fuel gas due to secondary power-on of the solenoid valve 1 , the volume increment and pressure stabilizing functions of the pressure stabilizer 4 can avoid sudden opening of the first MFC 2 and the second MFC 3 due to sudden change in gas pressure in the line, avoid fuel gas entering the exhaust burner and the reformer, effectively avoid fuel gas entering the stack via the reformer in case of hot start in the process, avoid carbon deposits in the stack, and reduces stack hazard.

In a specific embodiment of the present invention, the pressure stabilizer 4 is internally provided with a gas flow storage area communicated with the main line 10, the exhaust burner branch 11 and the reformer branch 12, and storing the gas flow in the main line 10. The pressure stabilizer 4 is internally provided with the gas flow storage area. The gas flow storage area are communicated with the main line 10, the exhaust burner branch 11 and the reformer branch 12 at the same time, thereby increasing the total gas flow volume of the lines between the solenoid valve 1 and the first MFC 2 / second MFC 3. In case of secondary power-on of the solenoid valve 1, resulting in sudden input of a gas flow, sudden change in the gas pressure inside the main line 10 will not occur due to the existence of the gas flow storage area in the main line 10, thereby effectively avoiding sudden opening of the first MFC 2 and the second MFC 3 due to change in gas pressure in the front section, effectively avoiding fuel gas entering the stack via the reformer during hot start and assuring stack safety.

In an embodiment of the present invention, the pressure stabilizer 4 comprises a gas flow filter unit, which removes impurities from the gas flow in the main line. During gas supply, a gas flow filter unit is arranged in the pressure stabilizer 4 to purify the fuel gas entering via the main line 10 to improve the quality of the fuel gas entering the reformer and the exhaust burner and optimize the combustion effect. The pressure stabilizer 4 is an oil removal filter. The oil removal filter can purify the fuel gas input from the main line 1 to improve fuel gas quality. Further, the oil removal filter also has a space that can accommodate gas flow, playing a role of a pressure stabilizing damper between the main line and the exhaust burner branch/reformer branch.

The volume of the oil removal filter available for storage of gas is several times of the volume of the gas in the line, so the total volume of the gas sealed between the solenoid valve 1 and the first MFC 2/second MFC 3 is larger than the space of the existing line. Supposing the temperature is not changed in the supply process of fuel gas, according to the equation of state of ideal gas, P1V1=P2V2 (P1 is the front-end gas pressure of the solenoid valve, V1 is the front-end volume of the solenoid valve, P2 is the front-end gas pressure of MFC and V2 is the front-end volume of MFC), when gas flow volume AV leaked by the first MFC 2 and the second MFC 3 is very small compared with the pressure-stabilized volume in the closed oil removal filter 4, the reduction of pressure P of the gas in this section will also be very small. When the gas leaked due to lag of the first MFC 2 and the second MFC 3 is not enough to make P2£2.6bar, the mass flow controllers will not be opened suddenly under stable pressure, thereby preventing fuel gas from entering the stack without control during hot start, causing carbon deposits in the stack.

Based on the SOFC gas line provided above, the present invention further provides an SOFC system vehicle, comprising a vehicle body and a stack hot box arranged inside the vehicle body, and further comprising an SOFC gas line communicated with the stack hot box. The SOFC gas line arranged on the vehicle body is the SOFC gas line provided by the foregoing embodiments.

As the SOFC system vehicle adopts the SOFC gas line provided by the foregoing embodiment, the beneficial effects of the SOFC system vehicle brought by the SOFC gas line are shown in the foregoing embodiment.

Various modifications to these embodiments will be apparent. The general principle defined herein can be implemented in other embodiments without departing from the scope of the present invention. Therefore, the present invention will not be limited to the embodiments provided herein.