Tham khảo tài liệu 'air pollution control systems for boiler and control problems_2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Simpo PDF Merge and Split Unregistered Version - http 5-815-1 AFR 19-6 CHAPTER 3 BOILER EMISSIONS 3-1. Generation processes The combustion of a fuel for the generation of steam or hot water results in the emission of various gases and particulate matter. The respective amounts and chemical composition of these emissions formed are dependent upon variables occurring within the combustion process. The interrelationships of these variables do not permit direct interpretation by current analytical methods. Therefore most emission estimates are based upon factors compiled through extensive field testing and are related to the fuel type the boiler type and size and the method of firing. Although the use of emission factors based on the above parameters can yield an accurate first approximation of on-site boiler emissions these factors do not reflect individual boiler operating practices or equipment conditions both of which have a major influence on emission rates. A properly operated and maintained boiler requires less fuel to generate steam efficiently thereby reducing the amount of ash nitrogen and sulfur entering the boiler and the amount of ash hydrocarbons nitrogen oxides NOx and sulfur oxides SOx exiting in the flue gas stream. Emissions from conventional boilers are discussed in this chapter. Chapter 13 deals with emissions from fluidized bed boilers. 3-2. Types of fuels a. Coal. Coal is potentially a high emission producing fuel because it is a solid and can contain large percentages of sulfur nitrogen and noncombustibles. Coal is generally classified or ranked according to heating value carbon content and volatile matter. Coal ranking is important to the boiler operator because it describes the burning characteristics of a particular coal type and its equipment requirements. The main coal fuel types are bituminous subbituminous anthracite and lignite. Bituminous is most common. Classifications and analyses of coal may be found in Perry s .
