EQUIPMENT - 15-INCH-DIAMETER ROTARY KILN
A 15-inch-diameter by 15-foot-long rotary-kiln pilot plant is available for testing at Hazen. The kiln can be used for drying, calcining, chemical conversion, thermal decomposition, combustion, and agglomeration studies.
The refractory-lined kiln is direct fired, and process gases pass countercurrent to solids flow. Its rotational speed is variable from 1 to 12 revolutions per minute, and the slope can be adjusted up to 10 inches per 15 feet.
Process heat is supplied to the kiln by a dual fuel, oil, or natural gas burner mounted in the product discharge end. The burner has a capacity of 500,000 Btu per hour, and process temperatures of up to 1000°C (1850°F) can be attained. The kiln exhaust gases are pulled through a dust-collection cyclone by a draft fan. A baghouse and scrubber can be installed to remove particulates, and an afterburner is available for providing final, high-temperature oxidation of the exhaust gases, when required.
Typical feed rates vary from 50 to 200 pounds per hour, and retention times can be varied from 30 to 240 minutes. Solid products can be sampled from the burden at points throughout the kiln length. Process temperatures and gas profiles can be measured at key locations within the kiln. Final product is collected after discharge through a water-cooled screw or by other optional methods.
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 constitutents, 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.