Incineration has become an essential tool in managing industrial and municipal wastes more sustainably, as long-landfilled materials such as hazardous medical wastes, petrochemicals, ammunitions, and more, have proven detrimental to the environment.
While many types of incineration equipment exist, the rotary kiln, a diverse and flexible thermal processing machine, continues to gain market share as the preferred method of incineration for a number of reasons.
About Incineration
Experts predict that the incineration market will grow in the coming years, as the world continues to produce mounting quantities of waste.
While an increasing focus on sustainability has improved waste generation and recycling, many wastes are simply not suitable for reuse or recycling. When recycling or reuse is not a viable option, incineration provides a much-needed outlet for wastes that cannot be recycled economically, or because of concerns over hazardous or toxic components.
Incineration can be used to process a wide variety of materials in the form of solids, liquids, gases, or sludge. Materials that are typically incinerated include:
- Chemicals
- Medical Waste
- Contaminated Organic Wastes
- Petrochemicals
- Ammunitions
- Solid Wastes and Sludges
Benefits of Incineration
Incineration offers several key advantages that have contributed to its increasing use:
Reduction in Waste Volume
Incineration significantly reduces the volume of waste by converting it to ash. This reduction in volume is a major environmental benefit, decreasing the amount of space the material will take up in a landfill and ultimately contributing to a declining need for landfills. A reduced volume also makes transportation more efficient (and more economical) because less hauling is required.
Mitigation of Hazardous Materials
When disposed of, hazardous components pose environmental threats to soil, air, water, and human and animal life. Through thermal decomposition, incineration eliminates hazardous components from the waste, taking them out of the environment completely and preventing any potential associated environmental degradation.
Energy Generation
Incineration also offers the benefit of recovering energy for use; a waste heat boiler can be employed to produce steam for use in the process, or to recover energy for making electricity.
Why Rotary Kilns?
Rotary kilns are used to carry out physical changes and chemical reactions in a variety of industrial settings. They are often chosen for their high-capacity and continuous production. When it comes to incineration, however, they are selected for one simple reason: flexibility.
Rotary kilns are capable of processing multiple types of waste streams at the same time – a quality that has become increasingly relevant in today’s waste management industry. Here’s why:
The Waste Management Industry is Changing
The ability to simultaneously handle multiple waste streams has become essential in today’s waste processing market. At one time, it was not uncommon for large manufacturers to have their own in-house incineration facility to handle the waste they produced, but as waste management became more complex, the industry moved to outsourcing incineration needs to avoid managing on-site facilities and the many complexities that accompany the task.
This developed into waste handling companies that collect waste from multiple sources and process it for a fee, which has since become the industry norm. In this type of business model, the rotary kiln provides the ideal processing solution, as waste processors need something that can handle the diverse range of waste streams they collect. If not for the rotary kiln, these processors would require multiple different types of systems to manage these waste streams.
The rotary kiln is also capable accepting feedstocks of varying moisture content and particle sizes, reducing the need for pre-treatment in many cases; from barrels to material fines, shredded waste, and everything in between, rotary kiln incinerators accept it all.
Wastes are Increasingly More Complex
In addition to the industry as a whole changing, the make-up of the waste itself is changing as well. While advancements in technology are producing more sophisticated products than ever before, they are also yielding more complex waste streams.
As rotary kilns are capable of simultaneously handling various types of feedstock, they offer a simple option for managing these increasingly complex waste streams.
How Rotary Kiln Incinerators Work
The process parameters of incineration may vary depending on the types of wastes being handled. In general, however, incineration employs controlled temperature profiles in order to volatilize organic components in the waste, thus eliminating hazardous compounds.
Though indirect-fired kilns are available, almost all rotary kiln incinerator systems utilize a direct-fired rotary kiln, where the products of combustion are in direct contact with the waste being processed. Material and combustion gases are fed into the rotating drum, which is sealed at both ends to maintain the required temperature profile within the kiln.
Most incinerators are configured with a co-current air flow, meaning the material and products of combustion flow parallel to each other in the kiln (i.e., the waste material and combustion products are fed into the kiln at the same end).
The rotary kiln is followed by a secondary combustion chamber with a separate burner that burns off any residual hazardous components remaining in the flue gas stream after the rotary kiln.
Waste with a high heating value can be used as a fuel source for the kiln itself, or for the secondary combustion chamber to further improve the sustainability of the operation.
Complete Rotary Kiln Incineration (RKI) Systems
Today’s rotary kiln incinerators are highly efficient and designed to comply with emissions regulations. A typical rotary kiln incinerator system consists of the following components:
- Waste storage
- Feed system
- Rotary kiln
- Secondary combustion chamber
- Emissions control system
- Controls
- Material handling
- Heat recovery system
Although these components are available separately, they are best purchased as a complete system from a single-source provider, as there are many integrated components and regulatory requirements that can be difficult to manage independently.
Conclusion
Incineration provides a valuable opportunity to manage both non-hazardous or hazardous wastes that are otherwise not economical or practical to recycle or reuse. As the incineration industry evolves to handle more complex and diverse waste streams, rotary kiln incinerators are becoming increasingly more widespread.
With more than 70 years of experience, FEECO is a world-renowned provider of custom thermal processing systems and rotary kiln incinerators. Our equipment is built to the highest quality standards for reliable long-term processing. Our Customer Service Team can also inspect, service, and repair rotary kilns of any brand. For more information on our rotary kiln incinerators or parts and service support, contact us today!