Kiln Technology Company Company is proud to be one of the nation’s leading providers of kiln installations, parts, repairs, and decommissioning services. Rotary kilns are a vital part of our nation’s industry, and we do everything we can to keep them running smoothly. Part of that involves educating our customers so they can run and maintain their kilns for years.
So, for the next two blog articles, we wanted to address some of the most common questions we hear about kilns – from basic to advanced. Let’s get started.
1 – What is a rotary kiln used for?
Rotary kilns are designed to provide ultra-high temperature environments for conducting several thermal processing functions. These include drying, as well as high-temperature chemical transformations. Some of the most common reactions include:
- Organic combustion
- Heat setting
- Sintering and induration
- Reduction roasting
- Thermal desorption
Probably the most common use for kilns in America is for the creation of raw concrete, by calcinating limestone at high temperatures.
2 – How do rotary kilns work?
A rotary kiln is basically a huge hollow drum, slightly tilted to provide downwards movement for materials within. Extremely high temperatures are generated in the kiln, intended to superheat any materials which are inside it. As the kiln rotates, these materials tumble so that they are evenly exposed to the heat, while moving slowly towards an exit port at the bottom.
If needed, the internal configuration can be altered to induce more tumbling, or to expose the materials to more heat before they pass through.
3 – What are direct and indirect rotary kilns?
There are two basic methods of heating a kiln: direct and indirect. This is straightforward. When the kiln has direct heating, the heat source is within the kiln itself, and the materials being processed are directly exposed to the heat. With indirect kilns, the outside of the kiln is heated instead, creating a more oven-like environment with diffused heating throughout.
4 – What fuels can rotary kilns use?
Rotary kiln manufacturers have a wide variety of fuel choices, and kilns are often designed around the most optimal fuels for their desired use. Often, they’re simply heated by coal, but they could also use fuel oils, natural gas or propane, electricity, or synthetic heating gasses. They may also reuse their own waste heat for pre-heating materials.
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