The cogeneration fuel cell system is a comprehensive energy supply device that directly converts fuel chemical energy into electrical and thermal energy through electrochemical reactions. It has the characteristics of high efficiency, cleanliness, and multi supply. The following is a detailed analysis of its core components and maintenance points.

1、 System composition

1. Fuel cell stack (core power generation unit)

-Proton Exchange Membrane (PEM) or Solid Oxide Membrane (SOFC): Depending on the fuel type, PEM is suitable for hydrogen fuel and operates at low temperatures (60-80 ℃); SOFC is suitable for natural gas or methanol, with high operating temperatures (600-1000 ℃).

-Electrode and catalyst: anode (hydrogen oxidation reaction), cathode (oxygen reduction reaction), catalysts are mostly platinum based or nickel based materials, and activity decay needs to be evaluated regularly.

-Bipolar plate: Conductive and separating battery cells, made of graphite or metal, requiring anti-corrosion treatment.

2. Fuel supply system

-Hydrogen/methane storage and transportation: High pressure hydrogen storage tanks or reforming hydrogen production modules (such as methanol steam reforming), equipped with pressure regulating valves and filters (to remove impurity particles).

-Humidifier device: Maintain electrode moisture (PEM requires hydration), and control humidity through a humidifier or circulating water system.

3. Air supply system

-Air compressor and intake filtration: compress air to 0.1-0.3MPa, filter impurities such as dust and oil mist (filter element needs to be replaced regularly).

-Boosting and cooling: High temperature models (such as SOFC) require a heat exchanger to preheat the intake air using exhaust waste heat.

4. Combined heat and power module

-Waste heat recovery system: Utilizing fuel cell waste heat (50-80 ℃ hot water or 100-200 ℃ high-temperature gas), heat is recovered through plate heat exchangers or heat pipes for heating, hot water, or absorption refrigeration.

-Thermal management unit: Adjust the coolant flow rate to maintain uniform temperature of the battery stack and avoid local overheating.

5. Power and Control System

-DC/AC conversion: The inverter converts DC power into AC power to meet the demands of the power grid or load.

-Intelligent monitoring platform: Real time monitoring of parameters such as voltage, current, temperature, pressure, etc., and automatic start stop and load adjustment through PLC or SCADA system.

2、 Key points of system maintenance

1. Daily maintenance

-Cleaning and Inspection:

-Check the fuel and air pipeline interfaces daily to prevent leaks (soap water leak detection).

-Clean the filter element, especially the air filter end (dust accumulation can increase intake resistance).

-Wipe the condensed water on the surface of the battery stack to avoid corrosion of the bipolar plate.

-Parameter monitoring:

-Record voltage, current, and temperature curves, and investigate the cause of abnormal fluctuations (such as a single chip voltage below the average value by 10%).

-Regularly calibrate sensors (such as oxygen concentration probes, hydrogen sensors).

2. Regular deep maintenance

-Fuel system maintenance:

-Check the sealing of the hydrogen pipeline every 500 hours and replace the aging sealing ring.

-Clean the reformer (if used) to remove carbon deposits or catalyst fouling.

-Air system maintenance:

-Replace the air filter element every month and check the condition of the lubricating grease in the air compressor.

-Clean the turbocharger (if equipped) to prevent dust accumulation on the blades from affecting efficiency.

-Thermal management maintenance:

-Clean the surface dirt (such as calcium and magnesium ion deposition) of the waste heat exchanger to ensure heat transfer efficiency.

-Check the pH value of the coolant annually and replenish or replace antifreeze/deionized water.

3. Replacement cycle of key components

-Catalyst layer: PEM cells should be replaced every 2-3 years (due to platinum loss causing a performance decrease of over 30%).

-Proton exchange membrane: Check once every 1-2 years, and replace immediately if the membrane is perforated or softened.

-Bipolar plate: The metal plate needs to be repaired with anti-corrosion coating, and the contact surface of the graphite plate should be regularly polished.

4. Fault handling and optimization

-Common faults:

-Uneven voltage: Single battery failure, requiring disassembly, repair or replacement.

-Insufficient heat generation: Check fuel flow rate or catalyst activity.

-Leakage risk: Insulation testing, repairing damaged insulation layers.

-Efficiency optimization:

-Adjust the stoichiometric ratio of fuel to air (λ=1.1-1.3) to avoid excessive consumption.

-Utilize waste heat to preheat fuel or intake air, improving the overall energy efficiency of the system.

3、 Long term shutdown and emergency response

1. Disable protection

-Drain the fuel and coolant, and inject inert gas (such as nitrogen) to prevent electrode oxidation.

-Start a short-term operation (1-2 hours) once a month to maintain component lubrication and activity.

2. Emergency plan

-Hydrogen leakage: Immediately cut off the gas supply, start the fan for dilution, and disable electrical equipment.

-Overheating alarm: Emergency stop, check if the cooling circuit is blocked.