James K. Neathery

Morpholine Nitrosation To Better Understand Potential Solvent Based CO2 Capture Process Reactions

The amine assisted CO₂ capture process from coal fired power plants strives for the determination of degradation components and its consequences. Among them, nitrosamine formation and their emissions are of particular concern due to their environmental and health effects. The experiments were conducted using morpholine as a representative secondary amine as a potential CO₂ capture solvent with 100 ppm standard NO₂ gas to better understand the nitrosamine reaction pathways under scrubber and stripper conditions. The role of nitrite in the nitrosation reaction was probed at elevated temperatures. The effects of different concentrations of nitrite on morpholine were evaluated. Formation rate, decomposition rates, activation energy, and the possible reaction pathways are elaborated. Thermal stability tests at 135 °C indicated the decomposition of nitrosamines at the rate of 1 μg/(g h) with activation energy of 131 kJ/mol. The activation energy for the reaction of morpholine with sodium nitrite was found as 101 kJ/mol. Different reaction pathways were noted for lower temperature reactions with NO₂ gas and higher temperature reactions with nitrite.

Triboelectrostatic Cleaning of Coal In-Line Between Pulverizers and Burners at Utilities

Pulverized coal combustors are the principal means for converting coal to electricity in the United States. Coals used in these combustors have to be beneficiated because of escalating specifications on fuel quality that help to increase boiler efficiency and decrease acid gas emmissions. Because coal is pulverized before its combustion in PC boilers, during which time substantial mineral liberation occurs, it may be beneficial to remove mineral matter from the combustibles by using dry beneficiation techniques after the pulverizers and within the burner pipes leading to the coal burners. One such technique is based on triboelectrostatics. It relies on establishing a differential charge on coal and mineral matter and then separating this charged mixture in an electrostatic field. This paper presents data obtained at a utility site that quantify the charge imparted on coal during pulverization and transport in a burner pipe, and compares these values to data obtained within a laboratory setting. The electr...

A Comparison of Fischer-Tropsch Synthesis in a Slurry Bubble Column Reactor and a Continuous Stirred Tank Reactor

A Slurry Bubble Column Reactor (SBCR) is a gas-liquid-solid reactor in which the finely divided solid catalyst is suspended in the liquid by the rising gas bubbles. SBCR offers many advantages over fixed-bed type reactors such as: 1) improved heat transfer and mass transfer; 2) isothermal temperature profile is maintained; and 3) relatively low capital and operating cost. Fischer-Tropsch Synthesis (FTS) takes place in a SBCR where the synthesis gas is converted on catalysts suspended as fine particles in a liquid. The synthesis gas flows in a bubble phase through the catalyst/wax suspension. The volatile products are removed with unconverted gases, and the liquid products are separated from the suspension. A gas distributor located in the bottom of the reactor produces the bubbles in the reactor. A considerable interest has been expressed in using the SBCR to carry out FTS particularly for the conversion of stranded natural gas into liquids. Currently, the Center for Applied Energy Research (CAER) is utilizing a Prototype Integrated Process Unit (PIPU) system for scale-up research of the FTS. The purpose of this study was to compare the performance and activity decline of a precipitated Fe/K Fischer Tropsch Synthesis (FTS) catalyst in a revamped slurry bubble column reactor (SBCR) to that of previous CSTR and SBCR runs using the same catalyst and operating conditions. The activity decline measured in the revamped SBCR system was shown to be similar to that of the CSTR experiments. The apparent activity decline in a previous SBCR run was due a transient startup effect from the slurry filtration system.

Desulfurization of bituminous coals: fluidized bed gasification of coal/phosphoric acid mixtures

The processing of coal:phosphoric acid mixtures using mild temperature (932°F) fluidized bed conditions is presented. Phosphoric acid promoted the desulfurization of the bituminous coals, producing chars that contained less than 20% of sulfur originally in the coals. Gaseous H2S was the primary sulfur-containing gaseous product. Pyritic sulfur was eliminated from the coal at a temperature as low as 410°F, whereas about 70% of the organic sulfur was removed from the coal at 932°F. In comparison with literature data, organic sulfur remaining in the char is suggested to contain thiophenic speciation. Phosphoric acid also decreased greatly the swelling character of the coals, and altered dramatically the yields of gas, condensate and char relative to that obtained during the processing of coal without acid.

Triboelectrostatic Coal Cleaning

This research has shown that both pressurized and suction configurations for utility pulverizers impart substantial and differential charge on mineral matter and combustible material in coal. The absolute value of the average charge per unit mass was the same order of magnitude for both utility systems and was in agreement with values obtained within a laboratory system. This differential charge can be utilized to beneficiate combustibles and mineral matter in-line between the pulverizers and burners under conditions typical to that of coal transport in the utility.

Mild Temperature, Fluidized Bed Gasification of Coal/Phosphoric Acid Mixtures: Partitioning Coal Sulfur to the Gas as H2S

1. Abstract The processing of high sulfur, Illinois basin coal using fluidized bed mild temperature gasification of coal/phosphoric acid mixtures is described. It is part of an overall coal utilization process which can minimize the production of wastes and maximize the synthesis of value-added products. Comparisons of product slates and the extent of desulfurization as a consequence of using the novel process are compared to traditionally practiced mild temperature gasification. It is shown that high sulfur coal can be desulfurized at temperatures as low as 500°C that the sulfur partitions to the gas phase as H 2 S. Product yields and their characteristics important for application are discussed.