| 摘要 |
PURPOSE:To prevent a heat exchanger from initiation of stress corroding cracks by forming a heat collection system from an exhaust heat collecting heat-exchanger made of stainless steel, a supply side heat exchanger made of carbon steel, and a circulative passage for the intermediate thermo-medium water having a low ion concentration. CONSTITUTION:The produced heat of a fuel cell 1 is absorbed by a cooling water 7 and collected back to an intermediate thermo-medium water 25 to make liquid contact through an exhaust heat collecting heat-exchanger 21, and it further undergoes heat exchange with an external thermo-medium water 12 having a high electric conductivity such as service water which makes liquid contact through a supply side heat exchanger 23. At this time, the cooling water 7 of a cooling water circulating system 5 contacts the heat exchanger 21 made of stainless steel alloy and holds a low electric conductivity, and the thermo-medium water 12 using service water having a high ion concentration contacts the heat exchanger 23 made of carbon steel to accomplish preventing initiation of stress corroding cracks. A condensate 9 having a low ion concentration collected by a condensate condenser 8 is used to the thermo-medium water 25 to suppress producing of scales. It is thereby practicable to preclude stress corrosive cracking of heat exchanger and suppress production of scales even though service water is used as the external thermo-medium water. |
