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Steam Production and Cooling Tower Water Treatment
Published in Paul N. Cheremisinoff, Handbook of Water and Wastewater Treatment Technology, 2019
Boiler feedwater, regardless of the type and extent of external treatment, may contain contaminants that can cause deposits, corrosion, and carryover. Deposits directly reduce heat transfer, causing higher fuel consumption, high metal temperatures and eventual material failures. Deposits, although most serious in the boiler, may also cause problems in the preboiler or after-boiler systems.
Waste Heat Recovery
Published in Stephen A. Roosa, Steve Doty, Wayne C. Turner, Energy Management Handbook, 2020
Temperature control of the boiler feedwater is necessary to prevent boiling in the economizer during low-steam demand, or in case of a feedwater pump failure. This is usually obtained by controlling the amount of exhaust gases flowing through the economizer with a damper, which diverts a portion of the gas flow through a bypass duct.
Energy, exergy and economic analyses on heat pump drying of lignite
Published in Drying Technology, 2019
Ming Liu, Shan Wang, Rongtang Liu, Junjie Yan
A conversion process from raw lignite to electricity is established in this study to evaluate the influence of heat pump drying on the energy efficiency of lignite utilization (Figure 3). In the LPPH, the heat pump drying system is used to predry the lignite, and the electricity consumed by the heat pump is provided by the lignite-fired power plant. The dried lignite is sent to the burner for combustion to release heat in the boiler. The boiler feedwater absorbs heat in the boiler to become live steam, which is sent to steam turbines to convert heat to electricity. Steam exhaust discharged by the steam turbine enters the condenser and condenses into water. The condensate passes through the low-pressure heaters, deaerator, feedwater pump, and high-pressure heaters in sequence. The temperature of condensed water is increased, and the water is sent back to the boiler to complete the steam Rankine cycle. Flue-gas is discharged from the boiler after passing through the air-preheater, the precipitator, etc.
Water Conservation Equals Energy Conservation*
Published in Energy Engineering, 2018
Boiler feedwater treatment systems utilize mechanical or chemical processes to remove unwanted constituents. Water softeners remove calcium and magnesium, using chemically engineered polystyrene resin beads that have an affinity for positive ions. Dealkalizers remove bicarbonates, sulfates, and nitrates. Deaerators remove dissolved oxygen and carbon dioxide. Together, these treatment systems allow increased cycles of concentration while maintaining the necessary water quality for safe operation of the boiler. Increasing the cycles of concentration and decreasing the blowdown will result in both natural gas and water consumption savings.