Revolutionizing Sustainability: Smart Drying Solutions Aiming for Net Zero

Different industries generate various side streams and waste streams as byproducts of their operations. These streams often contain valuable materials that can be repurposed, recycled, or transformed into new products, thereby reducing waste and promoting sustainability.

Here are a few examples of outcomes that can be derived from side streams and waste streams in different industries:

Waste-to-Energy

Drying technology enables the easy and energy-efficient transformation of sewage sludge from pulp factory wastewater treatment systems into biofuel pellets. For instance, you can produce fuel pellets from flotation sludge, turning its wastewater sludge into energy and simplifying waste management. This approach also improves the annual water balance and restores mechanical impurities in the sewage.

Transforming waste into new, recycled products 

Any fiber containing hemicellulose or polyose can be transformed into high-added value products through gentle drying technology. Drying of agricultural or marine biomass to produce cellulose pulp fibers functions as raw material for several use cases. Recycling side streams promotes a circular economy, enhances resource efficiency, and minimizes deforestation, especially in the forest and paper industries.

Developing a new product by mixing and drying 

Drying technologies also enable you to develop new products by combining and drying multiple side streams. For instance, mixing wastewater sludge with ash, yields a product that can be sold as fertilizer or soil conditioner. Dried fiber-rich soil conditioner improves the soil’s water-binding capacity.

Similarly, mixing sludge with sawdust results in a product that can be used as biofuel pellets.

Drying technologies can be effectively applied in several industries. Here are some examples of where drying technologies can be utilized and their potential applications:

Municipal Waste Management

Wastewater Treatment Plants: Drying technologies can be employed to process sludge generated from wastewater treatment plants. The dried sludge can be converted into fuel pellets or bricks, which can serve as a renewable energy source for heating or industrial processes.

Agriculture and Food Processing

Crop Residues and Biomass: Agricultural residue can efficiently be processed and transformed into biochar, biofuels, or other bio-based products, such as animal feed, organic fertilizers, or green building materials.

Fruit and Vegetable Processing: After drying fruit and vegetable waste, they can be transformed into ingredients for food products, such as natural food flavors or nutrient-rich powders used in the production of nutritional supplements.

Manufacturing and Industrial Sectors

Industrial Byproducts: Industrial byproducts can include steel slag or fly ash. The dried materials can then be used as construction materials, aggregates in road construction, or additives in cement production. 

Side Streams from Forest Industry: Drying side streams from the forest industry can facilitate their transformation into various products like compressed wood pellets for heating or as a source of raw material for the production of bio-based chemicals and materials.

Residues from Food and Feed Industry: Drying side streams such as fruit peels or leftover grains can create value-added products like animal feed or compost, reducing waste and maximizing resource efficiency.

Packaging Waste: Drying technologies can enable the recycling of packaging waste, such as plastic, paper, or cardboard. By drying and processing these materials, they can be transformed into new packaging materials or plastic pellets for the manufacturing of plastic products. 

Energy Production

Biomass Waste: Drying technologies can be applied to biomass waste generated in forestry operations, sawmills, or agriculture. The dried biomass can then be used as a feedstock for biomass combustion, anaerobic digestion, or gasification processes to produce renewable energy, heat, or electricity.

Thermal drying systems play a crucial role in preparing material flows for downstream unit operations, such as, pelletizing. These systems are designed to remove moisture from the feedstock, enhancing its suitability for different applications, such as pelletizing. 

Here’s a general overview on the process of how a thermal drying system works before its final application: 

Step 1: Feedstock Preparation 

The process begins by preparing the feedstock, which can include various materials such as biomass, agricultural residues, or sludge. Depending on the final application, the feedstock can be pre-treated. 

Step 2: Loading and Preheating 

The prepared feedstock is fed into the thermal drying system. The system typically consists of a drying chamber or conveyor belt, where the material moves through the drying process. Before entering the drying chamber, the feedstock may undergo preheating to elevate its temperature, enhancing the efficiency of the drying process. 

Step 3: Drying Process  

Inside the drying chamber, the feedstock is subjected to controlled heating. The drying system’s design ensures that the heat is evenly distributed to facilitate efficient and uniform moisture removal from the feedstock. 

Step 4: Moisture Evaporation 

As the feedstock is exposed to the controlled heat, the moisture within the material starts to evaporate. The heated air or gases in the drying chamber act as a carrier medium, absorbing the moisture released from the feedstock. The moisture-laden air or gases are then directed out of the drying system for further treatment or condensation to recover heat energy. 

Step 5: Air or Gas Handling 

The moisture-laden air or gases are typically passed through a series of air handling systems, such as cyclones, bag filters, or scrubbers, to remove particulate matter and capture any pollutants or odors. 

Step 6: Final Dried Product 

After the moisture evaporation process, the feedstock undergoes a transformation, becoming significantly drier and more suitable for pelleting. The specific moisture content required for pelleting depends on the characteristics of the feedstock and the desired quality of the pellets. 

It is important to note that the exact design and operation of thermal drying systems can vary depending on the specific technology and application. Factors such as feedstock characteristics, final dry matter content requirements, energy efficiency, and environmental considerations play a significant role in determining the optimal configuration of the thermal drying system. 

Gentle drying techniques offer several benefits compared to more aggressive drying methods. These techniques prioritize a careful and controlled approach to moisture removal, providing numerous advantages in various industries and applications. Here are some key benefits of gentle drying techniques: 

Preserving Product Quality: Gentle drying techniques aim to minimize thermal and mechanical stresses on the material being dried. By carefully controlling temperature, airflow, and drying time, these techniques help preserve the quality, integrity, and desirable properties of the product. 

Retaining Nutritional Characteristics and Energy Content: In the food industry, gentle drying techniques can help retain the nutritional content. By minimizing excessive heat and prolonged drying times, these techniques reduce the degradation of energy and other sensitive components, ensuring that the final product retains its energy content. 

Preventing Structural Damage: Aggressive drying methods can cause structural damage to delicate or fragile materials. Gentle drying techniques mitigate this risk by avoiding excessive temperature gradients and reducing the occurrence of cracks, warping, or deformation in the dried material. This is particularly important for materials such as textiles or sensitive chemicals. 

Energy Efficiency: While drying processes typically require energy, novel drying techniques can optimize energy consumption. By carefully controlling drying parameters and utilizing advanced heat recovery systems, these techniques maximize energy efficiency, minimizing energy waste and reducing operational costs. 

Environmental Considerations: Modern drying techniques often result in lower emissions and reduced environmental impact compared to aggressive drying methods. By operating at lower temperatures and optimizing energy usage, these techniques can help mitigate greenhouse gas emissions and minimize the carbon footprint associated with the drying process. This aligns with sustainability goals and environmental regulations. 

Extended Equipment Lifespan: Aggressive drying methods can place significant stress on drying equipment due to high temperatures and rapid airflow rates. Gentle drying techniques, by contrast, subject the equipment to less strain, potentially extending its lifespan and reducing maintenance requirements. This leads to cost savings and improves overall operational efficiency. 

Process Flexibility: Gentle drying techniques can be tailored to suit different materials, sizes, and moisture content requirements. The flexibility of these techniques allows for customization and optimization of the drying process for specific products or applications. This adaptability is valuable in industries with multiple side and waste streams.