Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: April-June 2005 (open access)

Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: April-June 2005

None
Date: June 1, 2005
Creator: Levy, Edward
System: The UNT Digital Library
Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: July-September (open access)

Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: July-September

Low rank fuels such as subbituminous coals and lignites contain significant amounts of moisture compared to higher rank coals. Typically, the moisture content of subbituminous coals ranges from 15 to 30 percent, while that for lignites is between 25 and 40 percent, where both are expressed on a wet coal basis. High fuel moisture has several adverse impacts on the operation of a pulverized coal generating unit. High fuel moisture results in fuel handling problems, and it affects heat rate, mass rate (tonnage) of emissions, and the consumption of water needed for evaporative cooling. This project deals with lignite and subbituminous coal-fired pulverized coal power plants, which are cooled by evaporative cooling towers. In particular, the project involves use of power plant waste heat to partially dry the coal before it is fed to the pulverizers. Done in a proper way, coal drying will reduce cooling tower makeup water requirements and also provide heat rate and emissions benefits. The technology addressed in this project makes use of the hot circulating cooling water leaving the condenser to heat the air used for drying the coal (Figure 1). The temperature of the circulating water leaving the condenser is usually about 49 C …
Date: October 1, 2005
Creator: Levy, Edward
System: The UNT Digital Library
Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: April-June 2003 (open access)

Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: April-June 2003

None
Date: July 1, 2003
Creator: Levy, Edward K.
System: The UNT Digital Library
Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: Januarly-March 2003 (open access)

Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: Januarly-March 2003

This is the first Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture, prior to firing in a pulverized coal boiler. A description is given of the equipment and instrumentation being used for the fluidized bed drying experiments. Results of fluidization and drying tests performed with North Dakota lignite, having a 6.35 mm (1/4 inch) top size, are presented. The experiments were performed with a 381 mm (15 inch) settled bed depth, with inlet air and in-bed heater surface temperatures of 44.3 C (110 F), and with the superficial air velocity ranging from 0.2 m/s to 1.4 m/s. Drying rate is shown to be a strong function of air velocity, increasing seven-fold from 0.2 m/s to 1.4 m/s. Increases in velocity from 0.75 m/s (minimum fluidization velocity) to 1.4 m/s resulted in a doubling of the drying rate.
Date: March 1, 2003
Creator: Levy, Edward K.
System: The UNT Digital Library
Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report (open access)

Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report

This is the fourth Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture, prior to firing in a pulverized coal boiler. A description is given of the equipment, instrumentation and procedures being used for the fluidized bed drying experiments. Experimental data were obtained during this last quarter on the effects of particle size on drying rate for a North Dakota lignite. Other experiments looked at drying a PRB coal. The tests comparing drying rates with lignite particles of different diameters were carried out with particle top sizes from 2 to 9.5 mm and covered a range of air velocities. The results show that drying rate increased with air velocity, but that, within the accuracy of the data, the data for all four particle size distributions follow the same curve. This suggests the higher drying rates associated with the larger particles are due to higher air velocities and not to any inherently different drying rates due to particle size. The drying data with the PRB coal show qualitatively similar behavior to that observed with lignite. However, quantitative comparisons of the drying rate data obtained so far for the …
Date: January 1, 2004
Creator: Levy, Edward K.; Caram, Hugo; Yao, Zheng & Feng, Gu
System: The UNT Digital Library
Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: July-September 2003 (open access)

Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: July-September 2003

This is the third Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture, prior to firing in a pulverized coal boiler. A description is given of the equipment, instrumentation and procedures being used for the fluidized bed drying experiments. Laboratory data are presented on the effects of bed depth on drying rate. These show that drying rate decreased strongly with an increase in bed depth as the settled bed depth varied from 0.25 to 0.65 m. These tests were performed with North Dakota lignite having a 6.35 mm (1/4 inch) top size, constant inlet air and heater surface temperatures, constant rate of heat addition per unit initial mass of wet coal and constant superficial air velocity. A theoretical model of the batch dryer is described. This model uses the equations for conservation of mass and energy and empirical data on the relationship between relative humidity of the air and coal moisture content at equilibrium. Outputs of the model are coal moisture content, bed temperature, and specific humidity of the outlet air as functions of time. Preliminary comparisons of the model to laboratory drying data show very good …
Date: October 1, 2003
Creator: Levy, Edward K.; Caram, Hugo; Yao, Zheng & Feng, Gu
System: The UNT Digital Library
Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: October-December 2005 (open access)

Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: October-December 2005

This is the twelfth Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture using power plant waste heat, prior to firing the coal in a pulverized coal boiler. During this last Quarter, the development of analyses to determine the costs and financial benefits of coal drying was continued. The details of the model and key assumptions being used in the economic evaluation are described in this report and results are shown for a drying system utilizing a combination of waste heat from the condenser and thermal energy extracted from boiler flue gas.
Date: January 1, 2006
Creator: Levy, Edward; Bilirgen, Harun; Levy, Ursla; Sale, John & Sarunac, Nenad
System: The UNT Digital Library
Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: Januarly-March 2005 (open access)

Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: Januarly-March 2005

This is the ninth Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture using power plant waste heat, prior to firing the coal in a pulverized coal boiler. During this last Quarter, comparative analyses were performed for lignite and PRB coals to determine how unit performance varies with coal product moisture. Results are given showing how the coal product moisture level and coal rank affect parameters such as boiler efficiency, station service power needed for fans and pulverizers and net unit heat rate. Results are also given for the effects of coal drying on cooling tower makeup water and comparisons are made between makeup water savings for various times of the year.
Date: April 1, 2005
Creator: Levy, Edward; Sarunac, Nenad; Bilirgen, Harun & Zhang, Wei
System: The UNT Digital Library
Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: October-December 2004 (open access)

Use of Coal Drying to Reduce Water Consumed in Pulverized Coal Power Plants Quarterly Report: October-December 2004

This is the eighth Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture, prior to firing in a pulverized coal boiler. Analyses were performed to determine the effects of coal product moisture on unit performance. Results are given showing how the coal product moisture level affects parameters such as boiler efficiency, power required to drive the fluidizing air fan, other station service power needed for fans and pulverizers, net unit heat rate, thermal energy rejected by the cooling tower, and stack emissions.
Date: March 1, 2005
Creator: Sarunac, Nenad & Levy, Edward
System: The UNT Digital Library