Abstract: Disclosed are a method and apparatus for reusing wastewater. The method for reusing wastewater disclosed herein includes: generating a mixed wastewater by mixing multiple types of wastewater (S20); performing a first purification by passing the mixed wastewater through a flocculation-sedimentation unit (S40); performing a second purification by passing an effluent of the flocculation-sedimentation unit through a membrane bioreactor (MBR) (S60); performing a third purification by passing an effluent of the MBR through a reverse-osmosis membrane unit (S80); and reusing an effluent of the reverse-osmosis membrane unit as cooling water or industrial water (S100).

Abstract: A method for recovering performance of a degraded polymer electrolyte fuel cell stack through electrode reversal. In detail, oxide films formed on the surface of platinum of a cathode is removed through an electrode reversal process that creates a potential difference between an anode and the cathode by supplying air to the anode instead of hydrogen and supplying a fuel to the cathode instead of air, thus rapidly recovering the performance of a degraded polymer electrolyte fuel cell stack.

Abstract: A method for accelerating activation of a fuel cell stack may shorten an activation time of the fuel cell stack and reduce the amount of hydrogen used. The method includes a process of applying a high current to the fuel cell stack for a prescribed amount of time and a shutdown maintenance process of pumping hydrogen to an air electrode reaction surface for a prescribed amount of time.

Abstract: A method for activating a fuel cell stack without using an electric load includes chemically adsorbing hydrogen into a catalyst of a cathode. Oxygen remaining in the stack is removed to seal and store the fuel cell stack while maintaining a negative pressure in the fuel cell stack. The method for activating a fuel cell stack does not require an electric load device, and therefore does not increase the number of activation equipment, thereby preventing the total production speed of the fuel cell stack from reducing in response to the stack activation.

Abstract: A method for recovering the performance of a fuel cell stack mounted within a vehicle is provided. A method includes a recovery process of continuously applying a predetermined load using a load device when an air supply is stopped and hydrogen is supplied to a fuel cell stack to output current from the fuel cell stack. Further, protons and electrons generated by hydrogen oxidation reaction at an anode are moved to a cathode, to produce hydrogen at the cathode and simultaneously remove oxide on the catalyst surface of the cathode.

Abstract: A method for activating a stack of a fuel cell is provided. The method includes supplying oxygen and hydrogen to the stack after starting an activation process to change the stack to an open circuit voltage (OCV) state and terminating the supply. Adjacent cells of the stack are electrically connected by a cell voltage sensing terminal board and the adjacent cells are shorted to allow a cell voltage to be 0V. Additionally, oxygen and hydrogen are resupplied to the stack and predetermined current density is applied for a predetermined time is executed. The voltage is again decreased to be 0V by applying current density exceeding the predetermined current density for a time exceeding the predetermined time through the open circuit voltage state to remove oxygen remaining in the stack. Oxygen and hydrogen are resupplied after a silent period has elapsed for a predetermined time after removing the remaining oxygen.

Abstract: A method for activating a stack of a fuel cell is provided. The method includes supplying oxygen and hydrogen to the stack after starting an activation process to change the stack to an open circuit voltage (OCV) state and terminating the supply. Adjacent cells of the stack are electrically connected by a cell voltage sensing terminal board and the adjacent cells are shorted to allow a cell voltage to be 0V. Additionally, oxygen and hydrogen are resupplied to the stack and predetermined current density is applied for a predetermined time is executed. The voltage is again decreased to be 0V by applying current density exceeding the predetermined current density for a time exceeding the predetermined time through the open circuit voltage state to remove oxygen remaining in the stack. Oxygen and hydrogen are resupplied after a silent period has elapsed for a predetermined time after removing the remaining oxygen.

Abstract: A method for accelerating activation of a fuel cell stack may shorten an activation time of the fuel cell stack and reduce the amount of hydrogen used. The method includes a process of applying a high current to the fuel cell stack for a prescribed amount of time and a shutdown maintenance process of pumping hydrogen to an air electrode reaction surface for a prescribed amount of time.

Abstract: A method for activating a fuel cell stack without using an electric load includes chemically adsorbing hydrogen into a catalyst of a cathode. Oxygen remaining in the stack is removed to seal and store the fuel cell stack while maintaining a negative pressure in the fuel cell stack. The method for activating a fuel cell stack does not require an electric load device, and therefore does not increase the number of activation equipment, thereby preventing the total production speed of the fuel cell stack from reducing in response to the stack activation.

Abstract: A fuel cell management method includes removing droplets remaining in a fuel cell stack using air supplied to a cathode and hydrogen supplied to an anode. Hydrogen and oxygen remaining are removed in the fuel cell stack by stopping the supply of the hydrogen and the air, and the hydrogen and the oxygen in the fuel cell stack are chemically reacted to remove residual hydrogen and oxygen. Hydrogen is generated in the cathode of the fuel cell stack after removing the residual hydrogen and oxygen. The residual oxygen is additionally removed using the generated hydrogen, the generated hydrogen is absorbed on a surface of a catalyst layer formed on the anode and cathode and accelerating the chemical reaction of hydrogen and air.

Abstract: A fuel cell management method includes removing droplets remaining in a fuel cell stack using air supplied to a cathode and hydrogen supplied to an anode. Hydrogen and oxygen remaining are removed in the fuel cell stack by stopping the supply of the hydrogen and the air, and the hydrogen and the oxygen in the fuel cell stack are chemically reacted to remove residual hydrogen and oxygen. Hydrogen is generated in the cathode of the fuel cell stack after removing the residual hydrogen and oxygen. The residual oxygen is additionally removed using the generated hydrogen, the generated hydrogen is absorbed on a surface of a catalyst layer formed on the anode and cathode and accelerating the chemical reaction of hydrogen and air.

Abstract: A method for recovering the performance of a fuel cell stack mounted within a vehicle is provided. A method includes a recovery process of continuously applying a predetermined load using a load device when an air supply is stopped and hydrogen is supplied to a fuel cell stack to output current from the fuel cell stack. Further, protons and electrons generated by hydrogen oxidation reaction at an anode are moved to a cathode, to produce hydrogen at the cathode and simultaneously remove oxide on the catalyst surface of the cathode.

Abstract: A method for recovering performance of a degraded polymer electrolyte fuel cell stack through electrode reversal. In detail, oxide films formed on the surface of platinum of a cathode is removed through an electrode reversal process that creates a potential difference between an anode and the cathode by supplying air to the anode instead of hydrogen and supplying a fuel to the cathode instead of air, thus rapidly recovering the performance of a degraded polymer electrolyte fuel cell stack.