In Solid Oxide Cell (SOC) systems, the Balance of Plant (BOP) components are essential auxiliary systems that ensure the stack operates safely, efficiently, and reliably. The BOP manages gas/fluid distribution, thermal management, pressure control, humidity regulation, and system monitoring. These components are critical regardless of whether the SOC is operating in Fuel Cell mode (SOFC) or Electrolysis mode (SOEC).

Burner

The burner is a critical component in energy conversion and thermal management systems, responsible for mixing fuel and air efficiently and combusting it to generate controlled heat. In SOC systems, the burner provides essential thermal energy for stack operation, supporting both Fuel Cell (SOFC) and Electrolysis (SOEC) modes, including system startup and high-temperature operation.

The burner features a narrow-slot design, offering the following advantages:

1. Wide air-fuel ratio capability: Supports high air-fuel ratios ranging from 15 to 20 for efficient combustion.

2. Rapid cold-start: One-touch automatic ignition under low-temperature conditions for quick startup.

3. Multi-mode combustion: Compatible with direct fuel combustion during cold start as well as exhaust-gas-assisted combustion during normal operation.

Heat Exchanger

The heat exchanger is primarily used for preheating air and fuel gases. It utilizes high-temperature exhaust gases to raise the temperature of incoming air and reformed hydrogen-rich fuel gas to the required operating temperature of the stack.

Working Principle

The heat exchanger transfers heat from high-temperature gases or liquids to lower-temperature fluids through the thermal conductivity of metal or ceramic materials, achieving heat recovery and utilization. Its core principles include:

• Thermal Conduction: Heat is transferred from the high-temperature medium to the low-temperature medium through the material’s inherent thermal conductivity.

• Thermal Convection: Fluid flow enhances heat transfer efficiency and optimizes temperature distribution.

• Multi-Stage Heat Exchange Design: Multiple channels and layered structures enable high-efficiency heat utilization while reducing energy consumption

Reformer

The reformer is used in Solid Oxide Fuel Cell (SOFC) power generation systems to produce hydrogen through fuel reforming. Fuels such as methanol, methane, and propane are humidified and, at a controlled temperature, react over a catalyst to generate hydrogen, carbon monoxide, and carbon dioxide. The required heat for this process is primarily supplied by the heat exchanger.

Working Principle

The reformer converts fuels such as methanol, natural gas, and propane into a hydrogen- and CO-rich gas mixture through catalytic reactions. The core reactions typically include:

• Steam Reforming:

CH3OH+H2O→CO2+3H2\mathrm{CH_3OH + H_2O \rightarrow CO_2 + 3H_2}CH3​OH+H2​O→CO2​+3H2​ CH4+H2O→CO+3H2\mathrm{CH_4 + H_2O \rightarrow CO + 3H_2}CH4​+H2​O→CO+3H2​

• Partial Oxidation: Under controlled conditions, the fuel reacts with oxygen or air to produce hydrogen and CO while releasing heat.

The heat required for these reactions is primarily supplied by high-temperature gases recovered from the heat exchanger or stack exhaust, enabling efficient energy utilization

Humidifier

The humidifier features a vaporizer specifically designed to achieve stable liquid water vaporization, with vaporization fluctuation below 1%, enabling stable switching across different flow rates. The outlet pressure is optimized based on the characteristics of the Solid Oxide Fuel Cell (SOC) stack. This design is specially intended for fuel humidification in fuel cells and for producing vaporized water in SOEC systems