Preliminary Evaluation of Instruments for on-Line Characterization of Coal-Oil Mixture Fuel

摘要

Results of recent tests on coal-oil mixtures (COM) indicate that on-line continuous monitoring of key parameters - mass flow, coal content, and viscosity - is possible. Availability of this instrumentation can enhance the operation of control systems for COM preparation and combustion. Accurate measurement of density or coal content in COM is needed to monitor the reproducibility of preparation processes. Accurate mass flow measurements, coupled with data on the coal content, can be used to determine the instantaneous Btu input to a burner. Atomization characteristics, partly dependent on the fluid viscosity, can be adjusted using on-line viscometers linked to the fuel preheater. This paper examines a number of on-line instruments to measure mass flow, coal content or density, and viscosity in a flow system installed in a COM Combustion Test Facility at the Pittsburgh Energy Technology Center (PETC). Instruments under study include a Micro Motion mass flow meter, which uses the Coriolis force exerted by a fluid flowing through a U-tube; an instrument manufactured by Auburn International, Inc., which relies on the dielectric properties of COM to determine coal content; and a Brookfield on-line concentric cylinder viscometer. These instruments are compared to other on-line devices that perform the same duties and to laboratory data. Useful operating ranges in terms of coal content and temperature are discussed. Recommendations are made for developing a system to measure the instantaneous Btu input to a boiler. (ERA citation 07:020810)