EQUIPMENT - 5-FOOT-DIAMETER SECTIONAL KILN
Hazen’s 5-foot-diameter by 2-foot-long sectional kiln is designed to emulate the process gas composition and heating profiles that are experienced in commercial-scale rotary kilns.
The kiln is constructed of carbon steel and is completely lined with insulating refractory. It is equipped with a variable-speed drive which allows rotational speed control in the range of 0.5 to 3 revolutions per minute.
The sectional kiln is heated by a gas-fired burner rated at 750,000 Btu per hour. The primary fuel for the burner is natural gas, but propane can be added if required. Process temperatures of up to 1100°C (2010°F) can be achieved in this unit. Gas flows and pressures in the system are controlled by the use of an induced-draft fan. Entrained solids are collected from the process gas stream in an external cyclone followed by a baghouse. An afterburner is installed after the baghouse to ensure complete combustion of the process gases before they are exhausted to the atmosphere.
The system is batch-fed, and product is discharged from a side port, as shown in the schematic. A typical test charge weighs up to 500 pounds. During testing, the kiln rotation can be stopped at predetermined times to withdraw calcine samples for performance evaluation analyses (chemical composition and mineralogy) corresponding to the time intervals.
The system is equipped with online instrumentation to obtain operating data. Process temperatures, pressures, and gas compositions, including O2, CO2, CO, SO2, NOx, and total hydrocarbons (THC), are monitored and recorded continuously. A gas chromatograph and mass spectrometer are available for measuring other gaseous constituents, such as water, hydrogen, nitrogen, and methane. A data-acquisition system is used to monitor and record selected process data. Emission sampling for organic compounds, metals, and other inorganic species can be performed as required, using EPA-approved methods.