Study on atomic sodium release from pulverised coal particles in a pre-mixed natural gas flame
Atomic sodium release during coal combustion has been shown to be a significant factor in fouling and corrosion of heat transfer surfaces within industrial coal-fired boilers. Although there has been significant research into the final forms of sodium from combustion, information about the release of sodium is limited. An initial study of the release of atomic sodium from pulverised coal particles in a pre-mixed natural gas flame was conducted using planar laser induced fluorescence, PLIF. Measurements were made of the intensity of sodium fluorescence, coal particle velocities and gas phase temperature within the flame in a purpose-designed laminar flame facility that provides similar time-temperatures history to coal particles in their early stages of combustion in an industrial coal-fired boiler. The velocity of the coal particles was measured to be about 6.1 m/s using particle streak velocimetry obtained from the natural luminescence of the hot particles and a 2.25 ms gate of the CCD camera. Temperatures were measured using thermocouples, and the maximum measured temperature was ~1500 °C. Calibration of the sodium fluorescence was not undertaken, but useful information was obtained of the release rate of sodium atoms from combusting pulverised coal particles.
Alkali Metal Partitioning in Ash from Pulverized Coal Combustion
Abstract The relationship between the original form of sodium and potassium in coal and the ultimate fate of these metals was explored through experimentation in a 17kw laboratory downflow combustor. Composition analyses of size segregated samples of airbone ash at exhaust conditions for six different coals are reported. In all cases sodium was enriched in the small particle size range, and was shown both to form a sodium rich fume as well as an enriched surface layer around existing particles. The fraction of sodium appearing in the small particle size range, and therefore previously vaporized, could be correlated with the fraction of sodium that was acid soluble and inversely with the amount of silicon present in the parent coal. Increased temperature led to a decrease in the amount of sodium vaporized. For the coals examined, potassium was present primarily in the mineral form. Although the fraction of potassium vaporized could be positively correlated neither with total nor with acid soluble forms of ...
Proposed beam diagnostics instrumentation for the LANSCE refurbishment project
Presently, the Los Alamos National Laboratory is in the process of planning a refurbishment of various subsystems within its Los Alamos Neutron Science Center accelerator facility. A part of this LANSCE facility refurbishment will include some replacement of and improvement to existing older beam-diagnostics instrumentation. While plans are still being discussed, some instrumentation that is under improvement or replacement consideration are beam phase and position measurements within the 805-MHz side-coupled cavity linac, slow wire profile measurements, typically known as wire scanners, and possibly additional installation of fast ionization-chamber loss monitors. This paper will briefly describe the requirements for these beam measurements, what we have done thus far to answer these requirements, and some of the technical issues related to the implementation of the instrumentation.