Case Studies
On this page we describe practical examples from nearly forty years of experience designing and implementing systems using the TORBED processor as their core for processes across a range of industries conducted at temperatures from ambient to around 1500ºC. The story starts with our origins, processing vermiculite.
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Vermiculite Processing
Vermiculite encompasses a large group of hydrated laminar magnesium-aluminium-iron silicates, which resemble mica. When heated, these exfoliate to form light particles. The TORBED processor was developed to offer an alternative 6-7m high furnaces that are the customary alternative. The TORBED processors’ thorough mixing, high heat and mass transfer and close control result ina higher quality,lighter and more consistent product with lower energy consumption. Consistent processing and minimising wastage, importantly result in more saleable product.
The precise capacity of our vermiculite machines varies with grade of raw material from 1 to 5 tonnes per hour.
We have sold over twenty of these machines to buyers located in Europe, North America and Asia.
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Flash Calcining And Calcining
TORBED processors, with their control and constant mixing, are effective when used to process fine particles. After extensive pilot trials on specially commissioned pilot plants, a 1.5m diameter TORBED Reactor was successfully commissioned in 1999 for the flash processing of sub-5-micron ore. Natural gas is injected into the base of the TORBED processor, where it is combusted. This method ensures efficient heat transfer and promotes rapid temperature rise within the reactor, essential for high-temperature processes like calcination.
Multiple dense phase conveying injectors are used to distribute the raw material feed around and into the TORBED Reactor’s process chamber. The calcined product is then carried out in the exhaust gas stream and collected in a bag filter after gas and solid cooling.
This TORBED processor system is highly optimized for rapid heating of fine particulate feed to extremely high temperatures (over 1,000ºC) in just milliseconds. This rapid thermal processing creates a unique environment that facilitates significant changes in the material properties of the feedstock, particularly its surface area.
These abilities, amongst others, distinguish the Torbed processors from rotary kilns and other types of calciner.
TORBED
Paper Sludge Drying
A TORBED dryer was installed at Sappi’s Maastricht facility in 2004. It is a multistage drying system designed to process 6 tonnes per hour of paper sludge. This sludge, which initially contains 60% moisture, is dried down to just 5% moisture, effectively removing 3.5 tonnes per hour of water. The system uses a waste heat source at 110ºC, significantly improving energy efficiency.
Further efficiency gains and cost savings were derived from TORBED dryer being capable of remote operation, unlike the industrial belt dryer that it replaced. It also increased system availability.
The dried product is used as bedding for animals. A circular economy win together with an emissions win: untreated waste paper sludge is typically put to landfill and decomposes, producing methane.
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Paper Sludge Recycling And Energy-From Waste
In 2024 we installed a pilot plant capable of both drying and calcining waste paper sludge. Once started, heat from the calciner is used to dry the paper sludge and to generate electricity. All-in-all, a circular economy win in a foundation industry, reducing emissions and creating energy from waste. In addition, the ash from the calcination process is cementitious and is undergoing testing (2024-5) to allow for certification as a cement substitute.
A final stage in the plant is the latest TORBED gas scrubber, using the calcined mineral to capture and store CO2.
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Biomass Dryers
The TORBED Biomass Dryers are a highly efficient and compact solution for drying biomass feedstock, such as sawdust and waste wood chips, making them ideal for biomass fuel production. These dryers offer several advantages over traditional industrial belt dryers or rotary drum dryers, including:
Compact and Efficient Design:
TORBED dryers take up less space and require less energy than bulkier alternatives like rotary drum dryers.
High Drying Capacity:
The largest TORBED dryers can process up to 10 tons per hour of feedstock, reducing moisture content from 50% to 12%, and removing 4.3 tons of water per hour.
Uniform Drying:
These dryers ensure even processing, preventing discoloration and maintaining the quality of the feedstock.
Versatility:
They are suitable for drying feedstock for industrial gasifiers, which require specific moisture content, making them a viable alternative to traditional drying systems.
With over 40 installations already in operation, TORBED dryers are a proven solution for the biomass industry, improving the efficiency of fuel preparation for biomass energy production.
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Gas Scrubbing
Our first dry gas scrubbing project, in the aluminium industry marked a significant advancement in controlling smelting exhaust emissions. The TORBED technology played a pivotal role in removing contaminants from the exhaust gases produced in aluminium smelting operations.
The TORBED reactor uses a re-agent, in this case alumina particles to adsorb pollutants from the exhaust gas stream. The technology can be configured in single or two-stage assemblies, offering unique adsorption properties and ensuring the purification of the gases before discharge.
One of the standout features is the low pressure drop across the TORBED processors, which is crucial when handling high volumes of exhaust gases (200,000 nm³/h or 117,500 ACFM per processor). Traditional methods like venturi reactors and fluidized beds often result in higher energy consumption and significant pressure drops, requiring larger processing plants and more reactants; up to 20 times more in some cases.
Prototype and Implementation:
- The first prototype was a 5000 mm reactor built in 1993.
- Following successful trials, a larger 6000 mm two-stage reactor was commissioned in 1994.
- The positive results led to the installation of 13 more 6000 mm TORBED reactors at the New Zealand Aluminium Smelters Ltd plant in 1995/96, achieving world-class scrubbing efficiency.
- In 1997, an additional 6 TORBED reactors were commissioned at Comalco’s Bell Bay smelter in Tasmania.
Key benefits to Comalco of using the TORBED technology were energy efficiency, compact design and reduced reactant use.
Overall, TORBED reactors have proven to be a high-performance and energy-efficient solution for dry gas scrubbing both in the aluminium industry and elsewhere.
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Combustion
TORBED reactors demonstrate remarkable versatility in handling combustion processes, offering controlled and efficient solutions across various industries. Their ability to manage a wide range of feedstock materials regardless of shape, size, or quality has led to their application in both industrial waste combustion and biomass-fuelled power generation. Below are examples a variety of combustion applications.
Spent Pot Lining (SPL) from aluminium smelting contains hazardous materials, including refractory, carbon, fluxes, and cyanide, making it a toxic waste. Comalco Aluminium Ltd of Australia, starting in 1987, developed a process to treat SPL safely. After attempts with other technologies such as rotary kilns and fluidized beds failed, a TORBED reactor successfully thermally dissociated the cyanide in the SPL. In 1990, a plant processing 3,000 tonnes per year of SPL was commissioned. By 1994, capacity increased to 10,000 tonnes per year, proving the effectiveness of the TORBED reactor in handling this hazardous material and producing a non-hazardous waste stream.
TORBED reactors are also employed for the controlled combustion of shredded wood waste, acting as a heat source for biomass-fuelled power plants. Two 5MWt TORBED combustors were installed to handle shredded wood waste. These reactors could deal with tramp feed materials, such as door handles, nails, and other incombustibles, proving their flexibility and practicality over conventional fluidized bed combustion systems.
TORBED technology’s compact design, coupled with its ability to handle incombustibles, makes it an attractive and cost-effective solution for industrial biomass combustion.
A further biomass-based application is in rice husk combustion, TORBED reactors offer precise temperature control, enabling the production of amorphous silica ash without creating significant quantities of cristobalite (a crystalline form of silica): TORBED reactors provide a low-pressure drop during processing, significantly reducing energy waste compared to traditional methods like rotary kilns or fluidized beds. The system’s compactness allows for easy integration into industrial plants while reducing the need for large ancillary equipment.
TORBED reactors offer a highly efficient, compact, and versatile solution for combustion applications, including the safe and effective treatment of hazardous materials like SPL and the combustion of biomass materials such as wood waste and rice husks. Their ability to handle diverse feedstocks while maintaining precise control over temperature and combustion conditions makes them a preferred alternative to conventional combustion technologies.
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Biochar
TORBED processors have extended their capabilities beyond combustion into industrial gasification, offering a highly efficient and compact alternative for producing biochar and syngas from various biomass materials such as waste wood, straw, and other miscellaneous biomass. This application is distinguished from combustion because gasification involves the partial oxidation of biomass, resulting in incomplete carbon burn-out and leaving behind biochar along with residual ash.
Gasification in a TORBED processor involves heating biomass in a controlled environment with limited oxygen, converting the feedstock into syngas (a mixture of hydrogen, carbon monoxide, and methane) and biochar. The biochar can have valuable applications, particularly in soil remediation, increasing nutrient availability, and reducing the need for chemical fertilizers. Biochar produced from straw in a TORBED gasifier has been analysed by the University of Leeds, where tests identified a surface area of 463 m²/g. This surface area can be significantly enhanced through activation using CO₂ or KOH (potassium hydroxide), making the biochar more effective for various industrial or agricultural applications.
TORBED gasifiers offer a space-saving solution compared to conventional updraft, downdraft, or fluidized bed gasifiers, while maintaining high efficiency in biomass conversion. They are also versatile, capable of handling a wide variety of feedstock materials.
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Devolatilisation
Devolatilization using TORBED processors has proven to be a highly effective method for removing hydrocarbons and other volatile components from various industrial feedstocks. TORBED technology has been applied in a range of applications, showcasing its efficiency, precision, and versatility over traditional methods like rotary kilns.
A TORBED processor was tested at BP’s Sunbury laboratories, processing 150 kg/h of oil-contaminated solids on behalf of a consortium of oil and gas companies. Following these successful tests, the consortium funded further development, leading to a transportable de-oiling plant designed for offshore use. The plant demonstrated the controlled removal of hydrocarbons from solids, providing an efficient solution for treating oil-contaminated materials in remote or offshore environments.
Metal wastes from machine shops, such as swarf and mill scale, are often contaminated with cutting oil and coolants. These contaminants cannot be directly introduced into remelting processes due to the risk of steam explosions and disruptive vapours. A TORBED processor was able to evaporate the oil and water from these wastes, providing up to 8 times higher throughput of consistent high-quality metal with minimal oxidation metal compared to rotary kiln-based methods, with significantly lower energy consumption.
In 2000 a1.8m diameter TORBED reactor was commissioned for the devolatilization of asphalt-coated road stone at a rate of up to 20 t/h.The TORBED reactor volatilizes the old asphalt, including polycyclic aromatic hydrocarbons (PAHs), allowing the cleaned road stone to be recoated and reused. The volatile by-products from the asphalt are thermally oxidized in the upper section of the reactor, ensuring that emissions are minimized and controlled. This closed-loop system makes the process both efficient and environmentally friendly.
A further devolatilisation application has seen TORBED processors successfully applied to the recycling of spent industrial catalysts containing hydrocarbons, carbon, and sulphur. Two processors were installed to remove these contaminants, facilitating the recovery and recycling of the catalysts while minimizing environmental impact.
TORBED reactors offer an advanced, efficient, and versatile solution for devolatilizing volatile components from a variety of industrial materials, from oil-contaminated solids and metal waste to spent catalysts and asphalt-coated road stones. With superior energy efficiency, precise control, and a compact design, TORBED processors are an ideal alternative to traditional methods, enabling cleaner processes and more consistent outputs.
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Food
TORBED processors have found extensive use in the food industry, accounting for 40% of our historical sales. Their applications range across multiple food categories, such as cereals, snack foods, spices, and coffee/cocoa roasting, offering improved efficiency, product quality, and versatility.
With a growing consumer demand for low-fat and healthier snacks, TORBED processors have been instrumental in developing new products, particularly expanded “half pellet” snacks that are lighter and healthier than traditional fried or extruded products. TORBED processors can produce lighter, higher quality, and more consistent products with lower energy consumption than traditional methods. Certain product shapes, which can’t be air-expanded in other machines, can only be achieved in a TORBED processor due to its precise control. TORBED processors are used for this type of application in major food production facilities across Europe, Australasia, the Americas, and the Middle East, with throughputs ranging from 50 to 500 kg/h.
Nearly half of the dryers sold by Torftech are used in the food industry, primarily for drying starch powders like potato starch. Other products dried include carob powder, carrot flour, cheese, dextrin, and distillate solids. TORBED dryers offer a compact design and energy efficiency, while maintaining product quality.
Traditionally, spices are pasteurized using steam or radiation, both of which have limitations in terms of product quality and pasteurization levels. Extensive trials show that TORBED processors can achieve much lower residual contamination than traditional methods when using hot air. The process ensures:
- Higher product quality
- More consistent results
- Low energy consumption
Full-scale plants handle 300–400 kg/h of spices and other food ingredients.
TORBED processors have been used for the roasting of coffee and cocoa beans, providing an efficient alternative to rotary kilns. This application has seen successful installations across the UK and continental Europe. The technology has also been extended to the roasting of nuts for snack products, emphasizing the versatility of the system for different roasting needs.
Benefits of TORBED Processors in Food Applications:
- Energy Efficiency: TORBED processors use significantly less energy compared to conventional techniques, such as rotary kilns and traditional drying or roasting equipment.
- Compact Design: The installation of TORBED systems is quiet and space-efficient, making them easy to integrate into existing production lines.
- Product Consistency: The processors offer precise control, ensuring consistent quality in every batch, whether expanding snacks, drying powders, or pasteurizing spices.
- Adaptability: The system can be quickly adjusted for different food products and characteristics, making it a flexible solution for a wide range of applications.
TORBED processors have become a valuable technology in the food industry, contributing to the production of low-fat snacks, efficient drying of starches, spice pasteurization, and coffee and cocoa roasting. Their high throughput, compact design, energy efficiency, and product quality control make them a preferred choice for food manufacturers globally.