The ongoing push for implementing more sustainable practices continues to be at the forefront of industry. Increasing regulatory action, combined with an ethical responsibility, has forced industries of all types to investigate a more sustainable approach in every aspect of their business if they want to survive. What was acceptable even just a decade ago is no longer tolerable as humanity begins to face the harsh consequences brought on by generations of a disposal mindset.
There are many opportunities and avenues for increased sustainability, but as has been witnessed in the FEECO Innovation Center, existing and new thermal processing techniques are turning out to be a key tool in the effort to move toward a more sustainable society. Here, we’ll examine the many and diverse ways in which thermal processing is being applied to improve the sustainability of the world around us.
About Advanced Thermal Processing
The phrase “advanced thermal processing” is a broad term that can mean many things and covers many different processes. This might include:
- Calcination
- Reduction Roasting
- Heat Setting
- Incineration
- Sintering/Induration
- Organic Combustion
- Thermal Desorption
- And more…
With so many potential processes and applications, thermal processing is an incredibly flexible medium capable of carrying out a wide range of objectives for hundreds of materials.
It is no surprise then, that interest and research around applying thermal processing in novel ways has become a growing trend. As a result of the comprehensive, high-temperature testing capabilities offered in the FEECO Innovation Center, Process Engineers have been on the front lines of the development of many new concepts and processes, all centered around improving the world around us.
“At the end of the day, everything we’re seeing in the high-temp thermal market comes down to sustainability,” says Alex Ebben, FEECO Process Sales Engineer. “Every thermal project that comes through the door somehow ties back to making a process or product more sustainable, improving the reuse potential of a waste, or just reducing pollution in some way. It is very exciting to be working on and seeing these technologies first hand. These are the processes that are going to make tomorrow better for everyone.”
The Innovation Center utilizes a number of both batch- and pilot-scale direct and indirect rotary kilns, paired with advanced data collection and reporting capabilities, to help customers take their concept from idea to fully realized, commercial-scale production.
Indirect-fired batch kiln used for testing in the FEECO Innovation Center
Novel Thermal Processing Applications
Listed below are some of the current ways that thermal processing is being applied in novel approaches to advance sustainability efforts.
Production of Carbon Products
The production of carbon products via advanced thermal processing techniques has seen explosive growth in recent years. Hundreds of waste materials under biomass categories such as manure, agricultural residuals, forest products, and more, are now being seen as raw materials for value-added products.
The transformation of such materials can create a marketable product from what was once a waste management challenge. These products also often boast additional environmental benefits as well. The carbon products gaining the most momentum are biochar and activated carbon. These products are created through the pyrolysis of biomass sources in a controlled environment – typically a rotary kiln.
Biochar
Biochar is a highly diverse, charcoal-like material. It has principally been considered for use in soil restoration and crop production efforts, but researchers are finding that it can offer a range of benefits in other settings as well. This includes potential use as an adsorbent in water treatment, a tool for limiting nitric oxide emissions from soil, and even improving the production of biomethane during anaerobic digestion, among many others.
Biochar looks to be a critical tool in reaching a more sustainable approach to solving many of today’s globally recognized problems.
Biochar (right) after pyrolyzing raw wood (left) in an indirect kiln.
Activated Carbon
Activated carbon is an upgraded product created in a similar pyrolysis process with added steam activation. A premium adsorbent with many applications in environmentally focused efforts, activated carbon has various uses in air pollution control and water treatment.
While activated carbon is a fairly established product, its application in new settings is calling for a deeper understanding of how this innovative material works. Biochar is a less established industry, with a fair amount of research and development around the material still needed. Ebben, along with colleague, Michael Eidge, recently presented a paper at the Biochar 2018 conference regarding their work in developing a baseline of material characteristics correlated with process parameters. The paper was entitled, Critical Characteristics of Wood-based Biochar Correlated with the Pyrolysis Process in an Indirect Kiln.
For more information on these carbon products and how they are produced, see our article and infographic, The Thermal Conversion of Biomass to Activated Carbon (and Everything in Between).
Material Recovery & Recycling
Material recovery and recycling have also become a primary focus of sustainability efforts. What were once viewed as wastes, are now being viewed as a potential source of raw materials.
The very foundation of material recovery and recycling often centers around breaking a product down into its most simple parts, or driving a chemical reaction or phase change that will convert it to a more useful or more capturable state. As such, many recovery and recycling processes would not be possible if not for advanced thermal processing techniques.
The wealth of products that can be recovered from wastes or process by-products via thermal processing is innumerable. Metals have been an area of particular interest, as finite resources dwindle in the face of booming demand.
Metal Recovery
Metal recovery, particularly as it relates to precious metals, has long been a subject of research, but in many cases, hasn’t been economically viable. However, as utilizing every potential resource has become ever-more essential, these processes are becoming increasingly mainstream.
Materials frequently explored for metal recovery via thermal processing include:
- Electronic waste
- Industrial by-products such as
- Fly ash
- Red mud
- EAF dust
- And more
Advanced thermal processing is also vital in the aluminum decoating process, which maximizes aluminum recycling capabilities by removing the myriad of lacquers and coatings applied to aluminum products for end product use.
Facilitating Sustainability
The above applications all involve thermal processing as a direct method of improving sustainability. However, it’s important to recognize that thermal processing is also critical in an indirect role as well, helping to create many of the products that allow sustainable approaches to be realized. Two key examples are listed below.
Lithium from Spodumene
Lithium is the key component of lithium-ion batteries – the battery of choice in the electric vehicle movement. While lithium can also be derived from brines, processing from spodumene (a lithium ore) is becoming increasingly important. The production of lithium from spodumene is dependent on thermal processing technologies to extract usable lithium components. As such, thermal processing is helping to supply lithium to feed the insatiable demand of the lithium-ion battery market.
Catalysts
Catalysts are far from a new concept, but their increasing applicability in improving process efficiency and making reactions possible makes them ever-more important in sustainability efforts.
Research and development around catalysts is an increasing trend, with many new catalysts hitting the market. Catalysts can reduce energy requirements, decrease environmental impact, and aid in the creation of critical products and materials.
In his recent article, Reaction: Opportunities for Sustainable Catalysts for Chem Journal, Patrick Holland argues that catalysts are a fundamental part of achieving a more sustainable society: “This is where catalysis plays an important role, because studies in catalysis uncover new reaction pathways for chemical transformations of both known resources and unknown resources (including waste).”
Recent research around catalysts has seen a focus on managing greenhouse gases in the fight against climate change – particularly carbon dioxide.
Most catalysts would not be possible without thermal processing technology.
Rotary Kilns: The Thermal Processing Device of Choice
Thermal processing can be carried out using a variety of devices depending on the requirements of the process. One of the most frequently chosen devices is the rotary kiln, capable of carrying out all of the aforementioned processes and objectives.
Rotary kilns, sometimes referred to as calciners, are a high-temperature thermal processing device that are incredibly flexible and customizable, making them applicable in a wide range of settings. They can be engineered in a variety of sizes from small, batch-size units, to full-scale production units for high capacity settings. They are also often chosen for their long-term reliability.
Rotary kilns consist of a rotating drum, through which the material is processed either by direct contact with combustion gases (direct-fired), or by contact with the shell of the externally heated drum shell (indirect-fired).
Both configurations can offer a highly controlled processing environment to suit just about any process.
3D Model of a FEECO Direct-fired Rotary Kiln
Conclusion
As existing processes are applied to new materials, and researchers work on novel processes to solve a myriad of issues, thermal processing will continue to prove itself as a crucial tool in achieving a more sustainable society. Without thermal processing, many of the advancements humanity has made thus far, would likely not be possible.
FEECO is the industry leader in developing advanced thermal processing technologies and manufacturing the custom rotary kilns needed to bring them to commercial production. For more information on our feasibility or pilot testing, or our rotary kilns, contact us today!
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