Heat Exchangers for Cooling Boiler Flue Gas to Temperatures Below the Water Vapor Dewpoint

2011 ◽  
Author(s):  
Edward Levy ◽  
Harun Bilirgen ◽  
Michael Kessen ◽  
Daniel Hazell ◽  
Barbara Carney
Keyword(s):  
Heat Transfer ◽  
Water Vapor ◽  
Flue Gas ◽  
Heat Exchangers ◽  
Buoyancy Force ◽  
Power Plants ◽  
Vapor Condensation ◽  
Water Vapor Condensation ◽  
Funded Project ◽  
Condensed Water

Coal-fired power plants have traditionally operated with stack temperatures in the 300°F range to minimize fouling and corrosion problems due to sulfuric acid condensation and to provide a buoyancy force to assist in the transport of flue gas up the stack. However, as an alternative, there would be benefits to cooling the flue gas to temperatures below the water vapor and acid dew points, while capturing the condensed water vapor. This paper describes experimental results from a DOE and industry-funded project to develop condensing heat exchangers for application to coal-fired power plants. A system of condensing heat exchangers was designed, fabricated and tested using slip streams of boiler flue gas and experiments were performed to measure the effects of process parameters on rates of heat transfer and water vapor condensation. In addition, measurements were made to characterize the acid concentrations in the condensed water which collected on the heat exchanger tubes and to quantify the effects of the heat exchangers on flue gas mercury concentrations.

scholarly journals An Experimental Investigation of Water Vapor Condensation from Biofuel Flue Gas in a Model of Condenser, (1) Base Case: Local Heat Transfer without Water Injection

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 844
Author(s):  
Robertas Poškas ◽  
Arūnas Sirvydas ◽  
Vladislavas Kulkovas ◽  
Povilas Poškas
Keyword(s):  
Heat Transfer ◽  
Water Vapor ◽  
Flue Gas ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Water Injection ◽  
Vapor Condensation ◽  
Base Case ◽  
Water Vapor Condensation ◽  
Condensing Heat Exchanger

Waste heat recovery from flue gas based on water vapor condensation is an important issue as the waste heat recovery significantly increases the efficiency of the thermal power units. General principles for designing of this type of heat exchangers are known rather well; however, investigations of the local characteristics necessary for the optimization of those heat exchangers are very limited. Investigations of water vapor condensation from biofuel flue gas in the model of a vertical condensing heat exchanger were performed without and with water injection into a calorimetric tube. During the base-case investigations, no water was injected into the calorimetric tube. The results showed that the humidity and the temperature of inlet flue gas have a significant effect on the local and average heat transfer. For some regimes, the initial part of the condensing heat exchanger was not effective in terms of heat transfer because there the flue gas was cooled by convection until its temperature reached the dew point temperature. The results also showed that, at higher Reynolds numbers, there was an increase in the length of the convection prevailing region. After that region, a sudden increase was observed in heat transfer due to water vapor condensation.

scholarly journals Simulation of Water Vapor Condensation in a Partly Closed Structure: The Influence of the External Conditions of Temperature and Humidity

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Jean Batina ◽  
René Peyrous
Keyword(s):  
Water Vapor ◽  
Vapor Condensation ◽  
Bottom Wall ◽  
External Constraints ◽  
Water Vapor Condensation ◽  
Temperature And Humidity ◽  
External Conditions ◽  
Condensed Water ◽  
Closed Structure

Our aim is to determine the more significant parameters acting on the water vapor condensation in a partly closed structure, submitted to external constraints (temperature and humidity) which induce convective movements and thermal variations inside. These constraints locally lead to condensation of the water vapor, initially contained in the air of the volume and/or on the walls. The inside bottom wall is remained dry. Condensed water quantities depend on: (1) dimensions of the structure, (2) the air renewing and its hygrometry, and (3) the phase between thermal and hydrometric conditions. Peculiar conditions are needed to obtain a maximum of condensation.

Effect of substrate wettability and flexibility on the initial stage of water vapor condensation

Soft Matter ◽  
2019 ◽  
Vol 15 (48) ◽  
pp. 10055-10064
Author(s):  
Qi Che ◽  
Yongjun Lu ◽  
Fenghui Wang ◽  
Xiang Zhao
Keyword(s):  
Heat Transfer ◽  
Water Vapor ◽  
Vapor Condensation ◽  
Transfer Efficiency ◽  
Heat Transfer Efficiency ◽  
Initial Stage ◽  
Water Vapor Condensation ◽  
Condensation Mode

The condensation mode and heat transfer efficiency are significantly affected by substrate wettability and flexibility in the initial stage of vapor condensation.

Use of Condensing Heat Exchangers in Coal-Fired Power Plants to Recover Flue Gas Moisture and Capture Air Toxics

2013 ◽  
Author(s):  
Edward Levy ◽  
Harun Bilirgen ◽  
Joshua Charles ◽  
Mark Ness
Keyword(s):  
Water Vapor ◽  
Heat Exchanger ◽  
Power Plant ◽  
Flue Gas ◽  
Heat Exchangers ◽  
Power Plants ◽  
Operating Conditions ◽  
Dew Point ◽  
Air Toxics ◽  
Condensing Heat Exchanger

Heat exchangers, which cool boiler flue gas to temperatures below the water vapor dew point, can be used to capture moisture from flue gas and reduce external water consumption for power plant operations. At the same time, thermal energy removed from the flue gas can be used to improve unit heat rate. Recent data also show that emissions of air toxics from flue gas would be reduced by use of condensing heat exchangers. This paper describes results from a slip stream test of a water cooled condensing heat exchanger system at a power plant with a lignite-fired boiler. The flue gas which flowed through the heat exchangers had been extracted from a duct downstream of the electrostatic precipitator. Measurements were made of flue gas and cooling water temperatures, flue gas water vapor concentrations, and concentrations of elemental and oxidized Hg at the inlet and exit of the heat exchanger system. Condensed water was also collected and analyzed for concentrations of H2SO4 and HCl. Results on the effects of the condensing heat exchanger operating conditions on oxidation and capture of Hg and on the capture of sulfuric and hydrochloric acids are described.

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