Impact of Fuel Type And Environmental Regulations

Fuel type has a significant impact on steam generator system configuration and design. Depending on the fuel type, widely differing provisions must be made for fuel handling and preparation, fuel combustion, fouling, corrosion, heat recovery, and emissions control. Figure 7-30 shows a comparison of very large gas- and coal-fired steam generators of the same capacity. Notice the gas system is far more compact due to minimal needs for fuel storage and handling. A much smaller furnace is needed for combustion; due to the absence of ash deposits, closely spaced heat transfer surfaces may be used. The coal system is much more complex and requires more extensive air emissions controls and equipment to collect and remove solid wastes.

Fuel type is perhaps the most significant factor with respect to environmental regulations. Coal systems present the most serious challenges and require the highest costs for compliance. Generally, natural gas presents the fewest difficulties, though with some technologies, uncontrolled NOx emissions may be close to that of distillate oil-fired systems.

There are numerous environmental considerations associated with boiler operation. Environmental protection and the control of solid, liquid, and gaseous effluents or emissions are key elements in the design and operation of all boilers. Combustion system emissions are strictly regulated by federal, state, and local governments, with requirements typically more stringent for larger capacity systems. Currently, the most significant emission control requirements relating to boiler combustion systems are for sulfur dioxide (SO2), oxides of nitrogen (NOx), volatile organic compounds (VOC), and airborne particulates. With coal-firing systems, numerous additional environmental regulations apply to fugative dust from coal piles and related fuel-handling equipment and for solid wastes arising from the collection of coal ash and from byproducts of flue gas desulfurization (FGD).

Additional environmental controls are required for aqueous discharges, which arise from a number of sources. These sources include boiler blowdown, boiler chemical cleaning solutions, cooling tower blowdown (which may be applicable to plants featuring condensing steam turbines), oil leakage, and a variety of other low volume wastes. Refer to section IV for additional detail on environmental regulations and compliance.

Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

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