OCR Text |
Show The Plane Flame Furnace System (con't.) Essentially, it consisted of a premixer/burner for pulverized coal and air, a vertical combustion chamber and an uprising flue connection. The burner supplied premixed fuel and air to the flame, the combustion chamber contained the flame, and the flue connection provided the necessary draft for maintaining flow through the furnace. In addition, several auxiliary pieces of equipment were necessary and described by Howard and Essenhigh. The combustion chamber consisted of four vertical walls constructed of insulating refractory bricks, bonded together with high temperature mortar. The bricks were composed of 50 percent alumina and 50 percent silica, and could withstand up to 1530°C temperature. The height of the vertical combustion chamber was approximately 10', interior cross-section area was 6.5" x 6.5", and the thickness of the walls was 5". The height of the combustion chamber was increased from 7 to 10' to achieve longer coal particle residence time, and the wall thickness was increased from 2.5 to 5" to reduce heat loss. The combustion chamber was encased with 3/8" thick transite sheet which reduced heat loss and eliminated air leakage. To measure the fumace inner wall temperatures, twelve thermocouples were fixed along the longitudinal center line of the right side of the combustion chamber. The thermocouple wires (0.128" diameter, Pt/Pt-10% Rh) were insulated with alumina double-bore tubing (0.126" O x 0.0233" I.D. x 6" long) with one end closed. 2-15 |