Adjustable air foils for balancing pulverized coal flow at a coal pipe splitter junction

Abstract

An adjustable device installed at the inlet of conventional junctions/splitters () for on-line control of the distribution of coal among the outlet pipes is herein disclosed. The device includes a plurality of wake inducing airfoils () each positioned upstream of a plurality of flow channels in the riffler () for directing coal flow to the outlet pipes. Each wake-inducing airfoil has a cross-section defined by a width W that varies along its length H for creating upstream turbulence, and a particle wake that preferentially diverts the coal flow to one of the outlet pipes at the splitter junction without affecting primary air flow. For example, each wake inducing airfoil may comprise a rounded convex edge leading to straight tapered sides. The surfaces of the sides may be roughened or textured () for promoting turbulent boundary layers. In addition, conventional fixed or variable orifices may be used in combination with the wake inducing airfoils for balancing primary air flow rates. The device allows fine-adjustment control of coal flow rates when used in combination with the slotted riffler, yet it has negligible effect on the distribution of primary air, resulting in closely balanced coal flow, reduced pollutant emissions and improved combustion efficiency.