Whether you are using a rotary dryer, rotary kiln, or rotary cooler, there is one thing that all these instruments have in common: they all use methods of heat transfer to carry out their jobs. Heat transfer is how heat moves from one source to another. Understanding the types of heat transfer, and how they ...
After a material is chosen for your rotary kiln refractory, you must decide the desired heat loss. When efficiency is of concern, or very high temperatures are involved, often it is desirable to use multiple layers of refractory: a “working” layer, and an insulating layer. The working layer is what is in direct contact with ...
Refractory is what protects the shell of a direct rotary kiln from the heat within, so as you can imagine, choosing a quality refractory that is right for your material is extremely important in the design of a rotary kiln. Choosing a refractory that will fail quickly can have severe effects on the life of ...
Rotary drums are a valuable investment with the potential to have a long productive life with proper maintenance. While protecting this investment is not hard, it does take know-how, and routine maintenance. Luckily, this routine maintenance and knowledge go a long way in recognizing potential problems, and spotting when a rotary drum is in need ...
Holding the appropriate temperature within a rotary kiln is what allows the desired chemical reaction to occur. Sustaining that temperature, however, can be difficult if the right seal is not chosen. Almost all rotary kilns run at a negative pressure, meaning gas doesn’t leak out, but rather, air leaks in. Because rotary kilns are always ...
For various reasons, it is often desirable to increase retention time in the rotary kiln. In order to do this, the loading, or how much material is in the rotary kiln at one time, needs to be increased. This is done by adding what is called a "dam" to the interior of the rotary kiln. ...
Indirect fired rotary kilns are an effective method of processing materials, but sometimes it is necessary to take additional measures to ensure that the rotary kiln is processing efficiently. Indirect fired rotary kilns create heat transfer by conduction through the shell of the rotary kiln, rather than by means of a hot gas stream. Because ...
Bearing and drive components for a rotary kiln are similar to those on a rotary dryer. There are two types of arrangements for rotating a rotary dryer or rotary kiln: a chain and sprocket, or a gear drive. For either arrangement, there are two tires on the rotary drum that sit on top of trunnion ...
Once we have our preliminary rotary kiln size, we can start to think about the details of the rotary kiln internals. In the case of a direct fired rotary kiln, in which the hot stream of gas flows directly through the interior of the rotary kiln, refractory is usually needed. Arguably one of the most ...
Another aspect of rotary kiln design is deciding whether to go with a direct fired rotary kiln, or an indirect fired rotary kiln. The difference between the two is how the heat is introduced. In a direct fired rotary kiln, the heat is introduced directly into the internals of the rotary kiln, via a stream ...
After the material has been thermally and chemically analyzed, we can begin sizing the rotary kiln. The size of a rotary kiln is not only a function of capacity, but also the amount of heat that will be generated or required inside of the rotary kiln from the volatizing of the material. Using the thermal ...
Knowing the chemical composition of a material is a valuable asset in rotary kiln design for several reasons. One important reason is that many materials will combust inside the rotary kiln at high temperatures, creating more heat than was put into the rotary kiln. In this case, the rotary kiln needs to be designed to ...
The specific heat of a material is another central factor in the design of a rotary kiln. Specific heat is how resistant a material is to heating. By definition, it is how much energy it takes to raise 1 gram of material 1 degree Celsius. The specific heat of water is very high, meaning it ...
Before a rotary kiln can be designed, the material to be processed must go through a thermal and chemical analysis. Getting to know the material you are working with will let you know how the material is going to behave in the rotary kiln. Is your material going to melt? Vaporize? Explode? Things like the ...
Although rotary kilns are designed to be used for driving a chemical reaction, an issue that often comes up in the processing of a material is when to draw the excess moisture from the feedstock. Many times, there is an excess of moisture that needs to be removed from the material before it is converted ...
For many years, rotary kilns have been used across various industries to drive chemical reactions by thermal processing. Rotary kilns have become very established in fields such as cement, lime, and minerals. Because these thermal processing tools have been used almost exclusively in these industries, they have been designed to meet the needs of these ...
Previously, we looked at indirect fired rotary kilns in applications such as reactivating spent carbons, pulling valuable materials out of valueless carriers, and conducting thermal processes in inert environments. Now we will look at indirect fired rotary kilns in the application of processing finely divided solids. Indirect fired rotary kilns can be beneficial when the material ...
