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Fundamental Investigation of Fuel Transformations in Pulverized Coal Combustion and Gasification Technologies Annual Report

Description: The goal of this project is to carry out the necessary experiments and analyses to extend leading submodels of coal transformations to the new conditions anticipated in next-generation energy technologies. During the first project quarter, a technical kick-off meeting was held on the Brown campus involving PIs from Brown (Hurt, Calo), BYU (Fletcher), and B&W (Sayre, Burge). Following this first meeting the current version of CBK (Version 8) was transferred to B&W McDermott and the HP-CBK code developed by BYU was transferred to Brown to help guide the code development in this project. Also during the first project year, progress was reviewed at an all-hands meeting was held at Brigham Young University in August, 2001. The meeting was attended by PIs Fletcher, Hurt, Calo, and Sayre, and also by affiliated investigators Steven Burge from McDermott and Prof. William Hecker from BYU. During the first project year, significant progress was made on several fronts, as described in detail in the previous annual report. In the current second annual report, we report on progress made on two important project tasks. At Brown University: (1) Char combustion reactivities at 500 C in air were determined for a diverse set of solid fuels and organic model compound chars. These varied over 4 orders of magnitude for the chars prepared at 700 C, and over 3 orders of magnitude for the chars prepared at 1000 C. The resultant reactivities correlate poorly with organic elemental composition and with char surface area. (2) Specially-acquired model materials with minute amounts of inorganic matter exhibit low reactivities that fall in a narrow band as a function of wt-% carbon. Reactivities in this sample subset correlate reasonably well with total char surface area. (3) A hybrid chemical/statistical model was developed which explains most of the observed reactivity variation based on …
Date: January 1, 2003
Creator: Hurt, Robert; Calo, Joseph; Fletcher, Thomas & Sayre, Alan

Fundamental Investigation of Fuel Transformations in Pulverized Coal Combustion and Gasification Technologies Annual Report

Description: The goal of this project is to carry out the necessary experiments and analyses to extend leading submodels of coal transformations to the new conditions anticipated in next-generation energy technologies. During the first two projects years, significant progress was made on most of the tasks, as described in detail in the two previous annual reports. In the current third annual report, we report in detail on the BYU task on the properties and intrinsic reactivities of chars prepared at high-pressure. A flat-flame burner was used in a high pressure laminar flow facility to conduct high temperature, high heating rate coal pyrolysis experiments. Heating rates were approximately 10{sup 5} K/s, which is higher than in conventional drop tube experiments. Char samples from a Pitt No.8 coal and lignite were collected at 1300 C at 1, 6, 10, and 15 atm. Swelling ratios of the lignite were less than 1.0, and only about 1.3 for the Pitt No.8 coal. All coals showed slight increases in swelling behavior as pressure increased. The swelling behavior observed for the Pitt No.8 coal at each pressure was lower than reported in high pressure drop tube experiments, indicating the effect of heating rate on particle swelling. This heating rate effect was similar to that observed previously at atmospheric pressure. SEM photos revealed that bituminous coal has large physical structure transformations, with popped bubbles due to the high heating rate. TGA char oxidation reactivities were measured at the same total pressure as the char preparation pressure. The general trend was that the TGA reactivity on a gram per gram available basis decreased for both Pitt No.8 and Knife River lignite coal chars with increasing char formation pressure. The Pitt No.8 char intrinsic activation energy and oxygen reaction order remained relatively constant with increasing pressure. This new data provides …
Date: January 1, 2004
Creator: Hurt, Robert; Calo, Joseph; Fletcher, Thomas & Sayre, Alan
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