CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2020-179596 filed on Oct. 27, 2020, incorporated herein by reference in its entire.

BACKGROUND

1. Technical Field

The present disclosure relates to a fuel cell system.

2. Description of Related Art

The fuel cell system (fuel cell cogeneration system) disclosed in Japanese Unexamined Patent Application Publication No. 2016-012486 (JP 2016-012486 A) includes a desulfurizer that desulfurizes fuel gas and a reformer that generates anode gas containing a hydrogen gas by reacting the fuel gas desulfurized in the desulfurizer with water vapor. The fuel cell system further includes a recirculation passage for introducing a part of the anode gas generated in the reformer into the desulfurizer and is configured to desulfurize the fuel gas using hydrogen contained in the anode gas.

By the way, a piping for supplying fuel gas to the reformer may be opened to the atmosphere in a period between the time when the fuel cell system is manufactured and the time when the fuel cell system is installed at the site of use. Through the opened piping, oxygen and fungi, such as mold, may invade the inside of the recirculation passage. In addition, since water vapor that has not reacted in the reformer also flows in the recirculation passage, the water vapor may condense and the condensed water may accumulate inside the recirculation passage. Therefore, the inside of the recirculation passage is an environment in which mold can easily proliferate. Then, a proliferation of the mold invaded the inside of the recirculation passage may hinder the flow of the anode gas to reduce the amount of hydrogen to be introduced into the desulfurizer through the recirculation passage. In particular, in the case where an orifice member is provided on the recirculation passage, condensed water may accumulate in a passage hole of the orifice member, and thus the mold proliferated in the passage hole may block the passage hole. As a result, sufficient hydrogen may not be supplied to the desulfurizer, and the desulfurization of the fuel gas may be insufficient.

SUMMARY

The present disclosure provides a fuel cell system having a recirculation passage for introducing a part of the anode gas generated in a reformer into a desulfurizer, in which the blockage of the recirculation passage by the mold is prevented or suppressed.

An aspect of the disclosure relates to a fuel cell system including a reformer, a fuel gas passage, a fuel cell, a desulfurizer, a recirculation passage, and an orifice member. The reformer is configured to generate an anode gas containing hydrogen by reacting fuel gas with water vapor. The fuel gas passage is for supply of the fuel gas to the reformer. The fuel cell is configured to generate electrochemically reacting oxygen with the anode gas generated by the reformer. The desulfurizer is provided on the fuel gas passage and is configured to desulfurize the fuel gas flowing through the fuel gas passage using hydrogen. The recirculation passage through which the reformer communicates with the desulfurizer such that a part of the anode gas generated in the reformer flows into the desulfurizer. The orifice member is provided on the recirculation passage. The orifice member or at least a part of the inner wall of a portion that constitutes an upstream side from the orifice member in the recirculation passage is made of a material containing a material having an antifungal action.

With the fuel cell system according to the aspect, the orifice member provided in the recirculation passage or at least a part of the inner wall of the portion on the upstream side from the orifice member in the recirculation passage is made of a material containing the material having the antifungal action; therefore, a proliferation of a mold may be suppressed in the orifice member provided on the recirculation passage or in the region on the upstream side from the orifice member in the recirculation passage. As a result, the blockage of the recirculation passage by the proliferated mold is prevented or suppressed.

In the fuel cell system according to the aspect, the material having the antifungal action is a material having one or both of an action of suppressing the proliferation of mold (fungus) and an action of killing the mold. Hereinafter, a material having an antifungal action may be referred to as an antifungal material.

In the fuel cell system according to the aspect, the orifice member may be made of a material containing the material having the antifungal action.

In the fuel cell system according to the aspect, the orifice member may be made of a glass fiber reinforced resin containing the material having the antifungal action.

In the fuel cell system according to the aspect, the material having the antifungal action may be made of glass powder containing silver ions.

