A fluidized bed is a system used in various industrial processes where solid particles are suspended in an upward-flowing stream of gas or liquid. This creates a state similar to a fluid, allowing for better mixing and heat transfer. The particles behave like a liquid, which enhances reactions and improves efficiency in processes such as combustion, drying, and chemical reactions. In a fluidized bed, the flow rate of the gas or liquid must be carefully controlled to maintain the fluidized state. This technology is commonly used in applications like coal combustion, catalytic cracking, and waste treatment, making it an essential component in many manufacturing and energy production processes.