Rotary Kiln Systems

Rotary kiln gasifiers are a proven technology and are considered robust and dependable. These gasifier systems are comprised of a primary rotary kiln reactor, a secondary combustion chamber, flue gas treatment units and a control system. Rotary kiln gasifiers can be specifically designed to treat MSW, sludge, and hazardous solid waste.

The operating temperature of primary rotary kiln reactor is normally in the range of 1,000 °C. The steel kilns units are refractory lined with an insulating castable and a hard refractory which can be operated up to temperatures of 1400 °C.  Smaller, high temperature rotary kilns (up to 1450 °C) can also be used as slagging units that are ancillary to larger primary rotary kiln or fluidized bed gasifiers. 

 Rotary kilns have the advantage of being able to operate over a wide temperature range depending on the design and refractory used, and can handle a wide variety of waste components. However, they are limited as to waste capacity per unit compared to fluidized bed designs.

Rotary kiln  systems are normally used at scales of approximately 50 to 200 tpd in waste treatment capacity. For solid waste application, these gasifiers systems have a specially designed afterburner to assure maximum oxidation and minimal particulate emissions. They can be fitted with various options for emissions control, heat recovery to steam, hot water, and electricity. Rotary gasifiers can be built in modules comprised of two or three kilns each, connected to a single combuster unit boiler and air pollution control system.

The kilns normally rotate about an axis at an angle of few degrees from the horizontal. The angle and rotating speed assure the materials travel through the chamber at a controlled rate.  Ash be discharged and handled at the discharge end of the kiln through a dry or water seal ash removal device and filter belt-conveyer. 

Shown below are the layout for a small self contained rotary kiln MSW gasification system with slagging kiln, sorting facility, and electrical generators. The facility is designed for an urban area is enclosed in a building that allows the entire process to be observed from the outside.