Technology Type

Coal-fired power plants convert chemical energy stored in coal into electrical power through various technological configurations. Here's a comprehensive overview:

Basic Steam Cycle Configuration

Core Process

• Coal is pulverized to talcum powder fineness
• Pulverized coal is mixed with hot air and combusted in the boiler
• Heat converts water to steam in boiler tubes
• Steam drives turbines connected to generators

Plant types

• Subcritical plants:
  • These plants operate at lower pressures and temperatures:
  • Steam pressure below 3,200 psi
  • Temperature below 1,025°F (550°C)
  • Traditional drum-type boiler design
  • Efficiency ranges from 33-37%
• Supercritical Plants:
  • Developed in the late 1960s with advanced materials technology:
  • Steam pressure around 3,530 psi
  • Temperature around 1,050°F (565°C)
  • Uses once-through boiler design
  • Operates at pressures from 3,500 to 4,000 psi
  • Efficiency ranges from 37-42%
• Ultra-supercritical plants:
  • Represent the most advanced technology:
  • Steam pressure at 4,640 psi
  • Temperature between 1,112-1,130°F (600-610°C)
  • Efficiency can reach 45-46%
  • Current research targets even higher parameters:
    • Pressures of 5,300-5,600 psi
    • Temperatures of 1,290-1,330°F (700-720°C)

Coal Types and Impact

Coal Classification

• Anthracite: 86-97% carbon, highest heating value
• Bituminous: 45-86% carbon, most common for power generation
• Subbituminous: 35-45% carbon, lower heating value
• Lignite: 25-35% carbon, lowest grade

Impact on Plant Operation

• Higher quality coal produces better efficiency and lower emissions
• Coal properties affect handling systems, pulverizers, and boiler performance
• Moisture and ash content influence plant efficiency and maintenance needs

Advanced Technologies

Integrated Gasification Combined Cycle (IGCC)

• Coal is gasified to produce syngas
• Syngas powers gas turbines
• Waste heat generates steam for additional power
• Achieves higher efficiency than conventional plants

Emissions Control Systems

• Flue gas desulfurization for sulfur removal
• NOx control systems
• Particulate removal equipment
• Carbon capture options for newer plants

Plant Components

Fuel Processing

• Coal handling and storage systems
• Pulverizers and coal mills
• Primary air fans for coal transport
• Ash handling systems

Steam Generation

• Boiler with water-wall tubes
• Superheater sections
• Economizer for feedwater heating
• Steam drum and separation systems

The choice of technology depends on coal quality, environmental requirements, and desired efficiency levels. Modern plants increasingly incorporate advanced technologies for higher efficiency and lower emissions.