Tham khảo tài liệu 'central boiler plants episode 1 part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | TM 5-650 are used to provide combustion air. Overfire air and reinjection fans for stokers and primary air fans for pulverizers may also be required. Induced draft fans are used to pull the flue gas from the furnance through the boiler bank and any ductwork economizer air heater or dust collector provided. e. Controls and Instrumentation. Since operator safety and protection of the boiler are of great importance boiler feedwater controls and burner safety controls are required to guard against failures due to low boiler water or explosion. Combustion controls regulate the fuel and air flow to maintain efficient combustion. The high price of boiler fuel which justifies improved combustion controls also justifies the use of recorders and meters to monitor combustion and ensure optimum plant operation. f. Pollution Control Equipment. The combustion of fuel may generate a variety of pollutants in excess of limits set by regulatory agencies. The major pollutant emissions of present concern are particulate oxides of sulfur SOx and oxides of nitrogen NOx . The use of a fuel lower in ash or surfur content and modifications to the combustion process can be effective in reducing these emissions. If these fuels are too expensive or combustion modifications only partially effective pollution control systems can also be used to bring emissions within acceptabe limits. ĩỳpical pollution control systems are mechanical collectors fabric filters electrostatic precipitators wet scrubbers and tall stacks. g. Water Treatment Systems. Proper water treatment prevents scale formation on the internal surfaces of the boiler and reduces boiler and distribution system corrosion. SECTION II. ELEMENTARY 1-4. FOSSIL FUELS Fossil fuels are derived from the remains of plant and animal organisms. These organisms used carbon dioxide CO2 minerals water and energy from sunlight to grow. Over millions of years this material accumulated and the original carbohydrates and other organic materials were .
