The CTF is fully instrumented to provide on-line analysis of the flue gas. Three flue gas sampling ports are available, although only two are used on a regular basis. Emissions of CO and NO x are obtained at the furnace exit. All system temperatures, pressures, and flue gas analyses are recorded continuously to chart recorders and the system's computer-controlled data acquisition system. The coal is then charged to a microprocessor-controlled weight loss feeder from a transport hopper.
Combustion air is preheated by an electric air heater.
The pulverized coal is screw-fed by the gravimetric feeder into the throat of a venturi section in the primary air line to the burner. Heated secondary air is introduced through an annular section surrounding the burner. Heated tertiary air is added through two tangential ports located in the furnace wall about 1 ft above the burner cone. Located in the duct is a vertical probe bank designed to simulate superheater surfaces in a commercial boiler. The drop impactor technique provides a calculated measurement of deposit strength, taking into account the conditions under which the test was performed.