High temperature thermocouples for incineration kilns

One of the industrial applications of Kamet’s high temperature thermocouples is in incineration kilns. Here we explain a bit about the different types of kilns in this industry and which of our thermocouples and special sheath materials are most suited.

An incineration kiln, also known simply as an incinerator or a waste incinerator, is a specialized type of kiln or furnace used for the combustion of waste materials at ultra high temperatures. Its primary purpose is to thermally treat and dispose of various types of solid waste, reducing its volume and converting it into less harmful byproducts. Incineration kilns are used for different applications, such as:

• in the medical industry to dispose of infectious and biomedical waste
• hazardous waste facilities
• sewage sludge management
• chemical and petrochemical industries

For different industrial applications, a range of specialized incineration kilns have been designed. For each type we indicate which thermocouples are most suited.

Rotary kilns

Rotary kilns have additional parts known as secondary combustion chambers or afterburners, which help completely destroy hazardous materials. Inside these secondary chambers or afterburners, the temperatures can go up to 1300°C, depending on the specific type of waste being processed. The high temperatures are carefully controlled to break down and neutralize the hazardous parts of the waste, making it safer. One remarkable thing about these kiln systems is that they can also handle liquid waste effectively, next to solid waste materials. The liquid waste is carefully injected into a nozzle of the kiln combustion chamber, where it undergoes thorough treatment and is transformed into less harmful materials.

Cement kilns

A cement kiln incinerator is a choice for safely burning both hazardous and non-hazardous wastes. It is a type of furnace commonly found in cement factories. Compared to other incinerators, rotary kilns used in the cement industry are much bigger in size, having a larger diameter and longer length.

Cement production involves heating limestone at very high temperatures at the burning zones (around 1400°C) for extended periods. This extended high-temperature process creates a great environment for safely destroying hazardous waste materials.

For rotary kilns and cement kilns Kamet advises the use of ARI ultra high temperature thermocouples, specifically designed to measure extremely high temperatures up to 1700°C in hazardous environments. These thermocouples generally are type S, type R or type B thermocouples. For waste incineration furnaces, rotary kilns, cement kilns and fluidized bed furnaces, the thermocouples are often designed with thermowells made of silicon carbide, metal ceramic, or porous oxide ceramics such as C799. These thermowells are very well suited due to their exceptional resistance to high temperatures, hardness, and abrasion.

Waste incineration kilns

A waste incineration kiln is a special kind of oven used to handle and dispose of solid waste, both hazardous and non-hazardous. Its main purpose is to burn the waste at very high temperatures, which reduces the size and changes it into safer materials like ash and gasses. The incineration process is closely monitored to ensure that any dangerous parts of the waste are safely destroyed. For these types of kilns, regular thermocouples (type K, type N) are used for temperature measurement as the operating temperature of these kilns seldom exceeds 1100°C. However, there might be extra demands for sheath materials that have a good resistance against corrosion by combustion products. An example of an advised sheath material in this case would be AISI446.

Fluidized bed incinerator kilns

A Fluidized Bed Incinerator kiln is a waste treatment system that utilizes a bed of hot sand or other granular material to directly transfer heat to the waste. This method is commonly employed for the disposal of municipal sludge, efficiently and effectively breaking it down. For these types of kilns, regular thermocouples are used for temperature measurement as the operating temperature of these kilns does not often exceed 900°C. However, there might be extra demands for sheath materials that have a good resistance to corrosion by combustion products. An example of an advised sheath material in this case would be AISI446.