Question 1

Drying digestate – turning challenge to opportunity

Accepted Answer

Moisture is one of the biggest challenges in getting value from biogas digestate, but it can also be the key to unlocking its real potential. Across Europe, large agricultural cooperatives and regional biomethane hubs handle thousands of tons of wet anaerobic digestion residue every year. Moving and storing this material is expensive and restricted by strict spreading windows. With the right digestate drying process, that same wet residue can be transformed into a high‑quality organic fertilizer that supports modern nutrient recycling.
The moisture challenge in biogas digestate
Wet digestate creates heavy, bulky and time‑sensitive loads. It demands large storage volumes and frequent transport, and farmers can only apply it during limited spreading periods. As a result, many producers pay high logistics costs and risk wasting nutrients they could otherwise recover and reuse. Digestate drying tackles these issues directly by removing water and stabilizing the material.
How digestate drying reduces costs and increases flexibility
When you remove most of the water, drying can cut total mass by up to 70%. This reduction means lower transport costs, smaller storage requirements and more flexibility in when and where you apply nutrients. Drier, more stable material is easier to handle and plan for, which helps cooperatives and biomethane hubs optimize both operations and cash flow. Instead of managing a waste problem, you manage a predictable fertilizer resource.
Superheated steam digestate drying with ExergyPSSD®
With Exergy’s superheated steam drying system (ExergyPSSD®), digestate drying become a circular and energy‑efficient process. The technology uses superheated steam in a closed loop to both dry and sterilize the digestate. This approach minimizes emissions, recovers energy and produces a stable, sterilized product that can be safely stored or used all year round. The result is a robust digestate drying solution that fits into modern, integrated biogas and biomethane plants.

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Question 2

DDGS drying with superheated steam | Retrofitting DDGS dryers with ExergyPSSD®

Accepted Answer

Why DDGS drying with superheated steam matters
Modern ethanol plants operate under constant pressure: energy prices remain high, customers demand consistent, sustainable feed quality, and any safety incident can halt production overnight. Yet one part of the process still hides substantial untapped value: the DDGS drying line, where conventional drum dryers remain common—proven and familiar, but energy‑hungry, hard to control for final moisture, and burdened with inherent fire and explosion risk. Upgrading this step not only improves efficiency and safety but also secures a reliable pathway to high-value animal feed production.
Upgrading these DDGS dryers with ExergyPSSD® replace hot air with a closed‑loop superheated steam process, dramatically cutting energy use, removing oxygen from the system to eliminate explosion risk, and enabling more precise control of DDGS quality. As a result, plants can produce consistent, high-value animal feed while improving safety and sustainability. By replacing traditional DDGS dryers with the ExergyPSSD® superheated steam system, producers can turn DDGS drying from a cost centre into a competitive advantage and achieve production, cost, and decarbonisation goals faster — and with lower project risk.
Turning a bottleneck into an energy asset
Pressurised superheated steam drying with ExergyPSSD® turns a production bottleneck into a competitive advantage across the plant. Instead of rebuilding the entire dryer island, the technology replaces the existing drum dryer with an ExergyPSSD® superheated steam dryer while fitting into the current line layout, foundations, and utilities.
During operation, water evaporated from the DDGS is recovered as useful, pressurised steam instead of being lost up the stack. This allows up to 80–85% of the latent heat to be recycled. In turn, it reduces net energy use to roughly 150 kWh per ton of water evaporated. As a result, plants that replace hot‑air DDGS drying with ExergyPSSD® achieve lower thermal energy consumption, fully recoverable vapour heat for other on‑site processes, and a lasting reduction in fuel costs and CO₂ emissions.
Oxygen free DDGS drying with superheated steam – eliminating explosion risk at the source
Because the process runs oxygen‑free, it eliminates the conditions that cause dust explosions, fires, and smouldering at the source. As a result, plants can simplify explosion protection and reduce dependence on complex gas‑treatment systems. They can also ease ATEX and NFPA compliance while improving working conditions for operators across the DDGS island.
In addition, the closed steam loop prevents emissions to the atmosphere. This means odour and VOC stacks common to hot‑air dryers can often be reduced or removed, strengthening local air quality and community relations. Together, these improvements create safer operations, lower insurance exposure, and higher availability for the DDGS line.
High-value animal feed DDGS – preserving protein and fat quality

DDGS drying with superheated steam does more than remove water. DDGS passes through the dryer in seconds under controlled, oxygen‑free conditions. This prevents oxidation and preserve amino acids and fat quality. At the same time, proteins transform into a less water‑soluble, rumen‑protected form without becoming denatured. As a result, a higher share of bypass protein reaches the small intestine. The outcome is fully sterilised DDGS with greater nutritional value, longer shelf life, and improved storage stability. Feed compounders value this performance, as it supports the production of high‑value animal feed and premium DDGS contracts. Therefore turning the drying step into a lever for feed‑market positioning rather than a cost.
 
Retrofit — replace, don’t rebuild
When we talk about retrofitting DDGS dryers, we mean replacing the existing hot‑air drum dryer with an ExergyPSSD® superheated steam dryer while keeping the rest of the plant largely intact. In practice, this means we design the new dryer to fit into your current layout and process, connecting to existing upstream and downstream equipment, utilities, heat source, and structural footprint, without reusing the old dryer shell itself.
From a project perspective, this retrofit approach offers a practical route to decarbonisation and growth because you avoid rebuilding the entire dryer island while still gaining a modern, high‑efficiency superheated steam system. The ExergyPSSD® solution combines a compact vertical dryer with integrated energy‑recovery and condensate‑handling units, enabling large‑scale industrial integration with a small footprint and low specific energy use per ton of evaporated water.
In operation, cyclones separate the dried DDGS and feed it into the existing cooling, storage, and load‑out logistics, so current material‑handling systems can remain in place. With few rotating parts and a robust design proven in 24/7 service since the late 1970s, the technology delivers high availability, low maintenance needs, and predictable lifecycle costs, as demonstrated by reference plants that are still running reliably decades after start‑up.
Next steps for decarbonisation and growth
For ethanol producers under pressure from regulators, customers, and investors to cut energy use, emissions, and safety risks, DDGS drying offers a tangible way to act on all three. By retrofitting existing drum dryers with ExergyPSSD® superheated steam technology, plants can reduce net energy consumption and CO₂ emissions. At the same time, they remove explosion risks inside the dryer, eliminate odour stacks, and upgrade DDGS into a consistent, high‑value animal feed with superior nutrient quality. For many large dry‑mill sites, transforming DDGS drying from a constraint into a strategic advantage is one of the fastest ways to boost competitiveness in a tightening market.
If you’d like to explore what’s possible, Swedish Exergy can support you with feasibility studies, energy‑balance calculations, and pilot testing of your own stillage in a superheated steam DDGS dryer. Together, these steps create a clear roadmap for your next investment. Contact us to discuss your DDGS dryer retrofit and next steps.

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Question 3

Drying wet residues from distilleries & wineries.

Accepted Answer

Producers of vodka, whiskey, wine, and other spirits generate large quantities of wet residues such as stillage, distillers’ grains, and grape pomace. These materials contain proteins, fibers, organic acids, and energy-rich components, but their high water-content makes them bulky, perishable, and costly to transport or dispose of.
Swedish Exergy’s ExergyPSSD® (Pressurized Superheated Steam Drying) from Swedish Exergy uses superheated steam in a closed, pressurized loop to remove moisture rapidly, typically in 5–20 seconds. This gentle, oxygen-free process protects nutrients, avoids scorching, and delivers a sterilized, uniform product that can be used for high-value animal feed, energy production, or further processing.
Key benefits of drying wet residues with ExergyPSSD®

Lower waste costs and flexible logistics
– Dried stillage or pomace becomes compact, stable, and easy to handle, enabling long-distance transport, centralized valorization, or seasonal storage instead of time-critical wet disposal.
More value from each batch
– The dried product can be sold as high-quality animal feed, used as a fuel or bioenergy feedstock, or integrated into other bio-based products, creating new revenue streams from what is today often a cost.
Efficient, low-emission drying
– ExergyPSSD® recirculates steam and typically recovers 80–95% of the energy input, while the closed-loop design eliminates atmospheric emissions from the dryer and reduces the need for odor or VOC treatment.
Safe, consistent, and gentle on quality
– The oxygen-free environment removes the risk of fire and dust explosion, while the short residence time and uniform steam contact deliver a consistent moisture profile and protect sensitive components in the feed.

By replacing traditional hot-air drying or wet disposal with ExergyPSSD®, distilleries and wineries can stabilize their residue streams, reduce operating costs, and demonstrate tangible progress on circularity and ESG targets. Swedish Exergy has decades of experience with superheated steam drying in ethanol, animal feed, and food industries, providing robust, compact systems with low operating cost and long service life.
Swedish Exergy can help you test the concept before you commit. Through pilot drying and feasibility studies, you can see performance on your own material and review key data and product samples.
If you are exploring options for stillage, distillers’ grains, grape pomace, or similar streams, or want to understand how ExergyPSSD® could help your process, contact us and we&#8217;ll set up a meeting.

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Question 4

Turning brewer’s spent grain into high-value feed.

Accepted Answer

Every year, breweries handle large volumes of wet brewer’s spent grain (BSG) and other beer residues. These streams are rich in protein, fibers, and residual nutrients, but the high moisture content makes them heavy, unstable, and costly to move or store for more than a short time.
Swedish Exergy’s ExergyPSSD® (Pressurized Superheated Steam Drying) uses superheated steam in a closed-loop system to dry BSG in just a few seconds, while protecting valuable protein fractions and fiber structure for high-value feed applications. The oxygen-free environment prevents oxidation and off-flavours, and the result is a uniform, sterilized product with long shelf life and excellent nutritional value for ruminants and monogastric animals.
Key benefits of brewer’s spent grain with ExergyPSSD®

Easier handling and year-round availability – Dried BSG become a stable, free-flowing product that is simple to store, dose, and transport, turning a seasonal wet byproduct into a consistent feed ingredient
Higher feed value and better animal performance – The gentle, short drying time helps protect protein quality, increase bypass protein, improve starch gelatinization, and ensure complete sterilization, supporting better milk yield, weight gain, and animal health.
Strong energy efficiency, no dryer emissions – The closed-loop steam system typically recovers 80–95% of the input energy and operates without atmospheric emissions, VOCs, or dust from the dryer, reducing both energy costs and environmental footprint.
Safe operation and consistent quality – With no oxygen in the dryer, the risk of fire and dust explosion is minimized, while the short, controlled residence time delivers uniform moisture content and batch-to-batch consistency.

By moving from wet byproduct handling or conventional hot-air drying to ExergyPSSD®, breweries can turn BSG into a standardized, premium feed component, lower waste management costs, and support circularity targets in one integrated solution. Swedish Exergy has more than four decades of experience in superheated steam drying for animal feed and food residues, helping customers turn side streams into reliable profit drivers.
Swedish Exergy can help you test the concept before you commit. Through pilot drying and feasibility studies, you can see performance on your own material and review key data and product samples.
If you are exploring options for spent grain, trub, or other beer residues, or want to understand how ExergyPSSD® could help your process, contact us and we&#8217;ll set up a meeting.

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Question 5

Turning juice residues into valuable resources.

Accepted Answer

Every year, juice producers handle massive volumes of wet residues such as citrus peels, pulp, and fiber. These byproducts are rich in nutrients, fibers, and essential oils—but their high moisture content makes them expensive to store, move, or convert into value, drying juice residues can change that.
Swedish Exergy’s ExergyPSSD® (Pressurized Superheated Steam Drying) uses superheated steam in a closed-loop system to gently remove moisture while protecting sensitive compounds. The short residence time in the dryer—typically only a few seconds—helps preserve oils, fibers, and antioxidant-rich fractions that are crucial for high-value applications.
Key benefits of drying juice residues with ExergyPSSD®

Easier logistics and longer shelf life
– Dried citrus residues become stable, compact, and far easier to store and transport compared to wet byproducts.​
More value from every ton
– The dried product can be used for high-value animal feed, pectin extraction, combustion, or bio-based materials, instead of low-value disposal.​
Low energy use and no emissions
– The system recirculates steam and recovers up to 80–95% of the input energy, with no atmospheric emissions from the dryer.​
Sterilized, consistent quality
– Superheated steam ensures full sterilization and uniform dryness, reducing spoilage and quality variation between batches.

By switching from traditional hot-air drying or simple wet disposal to ExergyPSSD®, you can cut waste handling costs, create new revenue streams, and strengthen circularity targets—all in one step. Swedish Exergy has over four decades of experience delivering steam-drying solutions to the food and bio-based industries, helping turn residues into profitable, sustainable resources.
Swedish Exergy can help you test the concept before you commit. Through pilot drying and feasibility studies, you can see performance on your own material and review key data and product samples.
If you are looking at options for peels, pulp, or fiber streams, or want to understand how ExergyPSSD® could help your process, contact us and we&#8217;ll set up a meeting.

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Question 6

Test before you invest - with Swedish Exergy

Accepted Answer

Looking to boost efficiency, cut energy costs, or scale your drying process?
Our Pilot Testing and Feasibility Studies give you the clarity and proof you need before committing to a full installation.
Pilot Testing
&#8211; See real results on your own material.
We run drying tests, gather key performance data, and deliver product samples — giving you fast validation and confidence in the technology.
Feasibility Study
-Get a clear roadmap for your project.
We define requirements, outline timelines, map process flows, and provide transparent CAPEX/OPEX estimates to support smart decision-making.
&#8211; Reduce risk
&#8211; Speed up your investment process
&#8211; Make decisions backed by real data
Ready to move from idea to proven performance?
Contact Us and let’s get started.
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Question 7

From breweries to feed mills: Upgrading wet spent grain

Accepted Answer

Wet Spent Grain (WSG) is one of the largest by-products of beer and ethanol production
— rich in protein and fiber, but extremely difficult to preserve. 
Most breweries face the same issues with spent grain:
▪ High moisture = fast spoilage
▪ Seasonal overproduction
▪ Transportation challenges
▪ High drying costs with conventional systems
With the ExergyPSSD®, wet spent grain can be converted into a shelf-stable, high-value feed ingredient with:
▪ Uniform & predictable drying
▪ No oxidation or nutrient losses
▪ No VOC emissions
▪ Zero fire/explosion risk
▪ Minimal environmental impact
▪ Up to 80% heat recovery
Better feed quality, lower operating costs, and a more sustainable value chain — from brewery to farm.
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Question 8

Biogas digestate: A valuable byproduct of renewable energy

Accepted Answer

Biogas digestate is a key byproduct of anaerobic digestion, offering significant benefits for agriculture and environmental sustainability.
As biogas production expands, digestate plays an essential role in nutrient recycling and the circular economy.
What is biogas digestate?
Biogas forms when organic materials like food waste, agricultural residues, and energy crops decompose in an oxygen-free environment &#8211; anaerobic digestion. While biogas is the primary output, the remaining substance, biogas digestate, is rich in essential nutrients like nitrogen, phosphorus, and potassium.
These qualities make it an excellent organic fertilizer for sustainable farming.

How is biogas digestate used in the EU?
The European Union manages biogas digestate in various ways, depending on environmental policies and market demand. Typical applications include:

Fertilizer – Due to its high nutrient content, wet digestate is commonly applied to agricultural fields or processed into pelletized fertilizer, meeting EU standards for organic farming.
Composting & further treatment – Some digestates undergo composting or drying for stability, easier storage, and odor reduction. Separating them into solid and liquid fractions enables precise nutrient application.
Biogas recovery & advanced processing – Secondary digestion can extract additional biogas.
At the same time, technologies like ammonia stripping and membrane filtration help recover nutrients.
Limited disposal – While landfill disposal is discouraged, incineration may be necessary if digestate is contaminated or produced in excess.

The EU actively promotes digestate valorization through subsidies and policies, supporting its use in agriculture and soil restoration as part of a broader circular economy strategy. EU regulations, such as the Fertilizing Products Regulation (EU 2019/1009), set safety standards for nitrogen levels, heavy metals, and pathogens.
Is untreated biogas digestate safe for human health?
While biogas digestate is a valuable fertilizer, untreated digestate can harm human health and the environment if not managed properly.
One primary concern is pathogens and microorganisms, as raw digestate may contain harmful bacteria and viruses. However, proper
anaerobic digestion combined with post-treatment methods such as drying, pasteurization, or composting significantly reduces these risks.
Another issue is the potential presence of heavy metals and other contaminants, particularly in digestate derived from industrial waste or sewage sludge. This requires strict regulatory oversight to prevent harmful substances from entering the soil and food chain. Manure-based digestate can harbor antibiotic-resistant bacteria, raising concerns about its long-term environmental impact and prompting ongoing research.
Nitrogen and ammonia pollution is another challenge. Over-application of digestate can cause nitrate to leach into groundwater, affecting water quality. At the same time, ammonia emissions contribute to air pollution. The EU enforces strict regulations to tackle these risks, including a one-hour heat treatment at 70°C to ensure digestate safety before agricultural use.

Why further treat biogas digestate?
Biogas digestate contains a high moisture content, making storage, transport, and handling challenging.
Wet digestate can promote bacterial and mold growth and emit strong odors.
Drying digestate provides several advantages:

Easier storage & handling – Dried digestate takes up less space, resists spoilage, and can be transported efficiently over long distances.
Lower emissions – Proper digestate drying reduces greenhouse gas emissions compared to wet digestate.
Sterilization & nutrient retention – Drying eliminates pathogens while preserving essential nutrients. ExergyPSSD® also sterilizes the digestate during drying.

However, the drying process must be carefully managed to maintain the integrity of organic compounds and prevent nitrogen loss through ammonia volatilization. This occurs when ammonium, a nitrogen-rich compound found in fertilizers and organic matter, converts into ammonia gas and escapes into the atmosphere. Effective drying techniques can minimize this loss, ensuring that digestate remains a valuable and sustainable resource.

Exergy drying technologies for biogas digestate
Choosing the right dryer is critical to ensuring digestate quality and sustainability. Drying is often one of the most energy-intensive stages in further digestate processing, making efficiency a key concern. Inefficient methods are costly and can negatively impact the environment, product quality, and the bottom line.
Exergy&#8217;s pressurized superheated steam dryer (ExergyPSSD®) offers an energy-efficient and sustainable solution:

Up to 85% lower energy consumption – Compared to conventional dryers.
Excess steam recovery – Steam generated during drying can be recovered and reused for energy or heating other applications.
Complete sterilization – High-temperature steam sterilization kills pathogens, producing Class A biosolids.
Preserved nutrients – Unlike traditional hot air dryers, ExergyPSSD® prevents nutrient degradation, oxidation, and uneven drying.
Environmental sustainability – With no emissions released into the atmosphere, ExergyPSSD® contributes to a greener processing solution.

Maximizing the value of biogas digestate for a sustainable future
Biogas digestate is more than just a byproduct—it is a vital resource for sustainable agriculture and renewable energy. Its rich nutrient content plays is crucial in soil enrichment and the circular economy. Advanced drying technologies, such as Exergy’s superheated steam dryer, enhance digestate’s efficiency and environmental benefits by improving storage, reducing emissions, and ensuring safer application.
Combined with stringent EU regulations, these innovations help maximize digestate’s potential while minimizing risks.
Sustainability in the biogas industry goes beyond energy production. Responsible digestate management—from raw material selection to anaerobic digestion and post-processing—is crucial for a circular system. A sustainable biogas future relies on optimizing each process stage, with environmental responsibility at the heart of renewable energy production.

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Question 9

Biogas Digestate in the EU: A Sustainable Resource

Accepted Answer

Biogas digestate in the EU: 2024 Highlights
In 2024, the European Biogas Association (EBA) reported a notable 37% increase in the EU&#8217;s biomethane production capacity from previous years, reaching 5.2 billion cubic meters (bcm) annually. As a result, the growth has led to a rise in the production of biogas digestate, a nutrient-rich byproduct of the anaerobic digestion process. The EBA estimates that nearly 1 million ton of digestate are produced each year.
Common use: natural fertilizer
Farmers widely use digestate as a fertilizer to boost soil health and replace chemical alternatives. It’s rich in nitrogen, phosphorus, potassium, and organic matter.
Challenges with solid-liquid separation
While solid-liquid separation is the most common treatment, it has limitations:

Nutrient Imbalance: Liquid fractions lack phosphorus, while solid fractions are less versatile.
Environmental Risks: Poorly managed liquid fractions can lead to nutrient leaching and water pollution.
High Costs: Additional treatments like nutrient recovery increase expenses.
Odor and Pathogens: Separation doesn’t fully address odor or pathogens, requiring further processing.

Why dry biogas digestate?
Drying digestate resolves these issues by:

Sterilizing and reducing odors
Simplifying storage and transport
Recovering valuable nutrients for high-quality fertilizers

Technologies like ExergyPSSD® transform biogas digestate into a marketable, eco-friendly product with 10x higher energy value.
Biogas digestate isn’t just a byproduct—it’s a vital resource for a sustainable future.

Question 10

Season’s Greetings from Swedish Exergy

Accepted Answer

As we approach the end of 2024, we want to take a moment to reflect and express our heartfelt gratitude to everyone who has been part of our journey &#8211; our valued clients, trusted partners, dedicated colleagues, and supportive friends. Your trust, collaboration, and support have made this year truly exceptional. Together, we’ve achieved great things, and we couldn’t have done it without you.
While we wrap up 2024 on a high note, we’re filled with excitement for 2025 &#8211; a new year with opportunities and inspiration to accomplish even greater things together.
As we celebrate the holiday season, we wish you and your loved ones joy, peace, and prosperity.
From all of us at Swedish Exergy, thank you for being a part of our success.
Happy holidays and a very happy new year!

Question 11

Sustainable Industrial Process for Production of Non-Wood Paper Pulp

Accepted Answer

The paper industry is increasingly turning to non-wood sources and innovative drying techniques
in the quest for more sustainable manufacturing processes. One such breakthrough is steam drying, a method gaining traction for its efficiency and environmental benefits in producing non-wood paper pulp.
The Rise of Non-Wood Pulp
Traditional paper production relies heavily on wood pulp, leading to deforestation and significant
environmental impact. Non-wood pulp, derived from sources like agricultural residues like wheat straw, bamboo, grasses, and other fibrous plants, presents a viable alternative.
These materials are renewable and help reduce waste and conserve forestry resources.
Steam Drying: An Overview
Superheated steam is produced by heating steam beyond its boiling point. This results in a &#8220;dry&#8221; state with a natural tendency to absorb moisture. This makes it highly effective for drying, as the superheated steam efficiently removes moisture from wet products.
The Exergy Pressurized Superheated Steam Dryer (ExergyPSSD®), invented by Claes Münter, founder of Swedish Exergy, at Chalmers University in Gothenburg in the late 1970s, utilizes this principle. This innovative dryer is a closed, pressurized system and uses superheated steam as the drying medium. Steam drying of pulp with the ExergyPSSD® offers numerous advantages: a high drying rate, high energy recovery, no atmospheric emissions, no risk for fire or explosion during operation, sterilization, and a short residence time.
ExergyPSSD® is a more energy-efficient and environmentally friendly drying technology.

Maximizing Efficiency and Sustainability with ExergyPSSD®
 
Sustainable:
The ExergyPSSD® stands out not only for its efficiency but also for its environmentally friendly and safe design features. One of the key advantages of the ExergyPSSD® is its closed-loop design, which effectively eliminates emissions to the atmosphere. By containing and reusing the superheated steam within a sealed system, this innovative dryer ensures that no pollutants are released into the environment, making it an excellent choice for industries committed to sustainability.
Drying efficiency:
Superheated steam can provide high heat transfer rates, improving drying efficiency.
This can result in faster drying times, reduced energy consumption, and increased productivity.
Energy Efficiency:
All the moisture in the wet pulp becomes steam in the steam dryer. With no stack losses, this steam is not wasted but recovered. It can be used in many other processes within a paper manufacturing facility. It can also be sold as heat energy, used in a carbon capture process, or used to produce green electricity. This steam can also be used as a heat source for ExergyPSSD® with MVR technology (heat pump principle).
Safety and cost efficiency:
The ExergyPSSD® operates in an oxygen-free environment, eliminating the risk of fire or explosion and providing a safer working environment. It minimizes potential safety hazards and protects both personnel and facilities. The ExergyPSSD offers a compact, flexible design with minimal rotating parts, ensuring easy maintenance and high availability. Additionally, it is engineered for 24/7 seamless operation and is easily integrated with other processes for optimal energy efficiency.
Enhanced Product Quality:
Steam drying ensures uniform moisture removal, significantly improving the quality and consistency of the final paper product. ExergyPSSD® also minimizes thermal degradation of the pulp, preserving its natural properties and enhancing fibre strength.
Additional Benefits:
The steam drying process reduces transportation costs, extends storage life, and improves product quality overall, making it a highly efficient and effective solution for paper pulp manufacturing.
 
Implementation in Non-Wood Pulp Production
Integrating steam drying into the production of non-wood pulp involves adapting existing infrastructure or investing in new steam drying units. While the initial setup cost may be marginally higher than air dryers, long-term energy savings, and operational expenses make it a financially sound investment.
Moreover, the positive environmental impact aligns with growing consumer and regulatory demands for sustainable products.
ExergyPSSD® represents a significant advancement in the sustainable production of non-wood paper pulp. By combining the environmental benefits of non-wood raw materials with the efficiency of steam drying, the paper industry can reduce its ecological footprint while maintaining high quality. This innovative approach supports the conservation of natural resources and promotes a more sustainable and economically viable future for paper manufacturing.

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Question 12

Swedish Exergy Reveals A New Pilot Plant

Accepted Answer

Years ago, we expanded our services and explored new business areas by establishing a dedicated Research and Development (R&D) facility and pilot plant. This investment reflects our commitment to innovation and growth. This facility originated from the University of Chalmers in Gothenburg, Sweden, where we invented the superheated steam dryer, The ExergyPSSD®.
Initially, the pilot dryer was installed at the University of Chalmers. It remained there for several years before being relocated to our subsidiary, Exergy Dryers Pvt Limited, in India. Since then, the pilot plant has undergone significant modernization and upgrading. This includes the implementation of a state-of-the-art control system featuring Siemens S7 PLC and Wonderware InTouch SCADA.

Moisture/Temperature Relationship Evaluation In The Pilot Plant.
This R&D facility and pilot plant serve as a crucial platform for testing and developing new business areas. Additionally, it provides our clients with the opportunity to conduct feasibility studies and have their products tested in our dryer, enabling them to witness the benefits first-hand.
During the pilot tests, various operating parameters are explored. All to establish moisture/temperature relationships and assess the positive effects of steam on the product. Throughout the testing process, we generate dried product and condensate samples, which are carefully analysed for moisture content. The entire process is closely monitored and recorded using the SCADA system. Both pilot plants can run in continuous mode, ensuring efficient and thorough testing procedures.
We then provide the samples to our clients for their own studies and further testing. If necessary, we can also arrange for the samples to be sent to a local analytical laboratory for additional testing. The results of these analyses are shared between the client and Swedish Exergy. Consequently fostering a collaborative approach to product development.
Meeting The Growing Demands For The Pilot Tests.
Due to the overwhelming popularity of the pilot testing, and in response to the growing demands of our customers in Europe and America, we commenced the manufacturing of a second pilot plant in 2022.
We are thrilled to announce that the second pilot plant was put in operation in early 2023, and the initial tests have already been successfully completed.
Located in Sweden, this mobile pilot facility offers the flexibility to rent it for long-term testing and product development. It is equipped with a modern control system based on Siemens S7 PLC and WinCC SCADA, allowing for seamless operation.
We are proud of our ongoing commitment to research and development, and the establishment of our new pilot plant represents an exciting milestone in our journey. These facilities will undoubtedly continue to drive innovation, expand our business areas, and provide unparalleled services to our valued clients.
Thank you for your continued support.
Best regards,
Swedish exergy AB

Question 13

Optimal solutions for drying DDGS

Accepted Answer

Ethanol plants have discovered a way to transform distillers&#8217; grain into a valuable by-product rich in protein and fiber. What was considered waste is now considered a highly nutritious and cost-effective animal feed. However, this transformation brings its own set of challenges. Although wet cake can be sold locally, its limited shelf life presents obstacles in transportation over long distances or extended storage periods.
This is where we step in to assist you with drying DDGS.
Drying DDGS opens a world of possibilities.
Crops like corn, rice, and wheat serve as crucial ingredients in alcoholic beverage production and are also fundamental to ethanol manufacturing. Because of their nutritious composition, both brewers&#8217; spent grain and ethanol by-products are excellent for animal feed. However, the challenges associated with drying DDGS depend on the properties and origin of the feedstock and can be hard to tackle.
Challanges to face.
Variations in particle size can impact not only nutrient digestibility and palatability but also mixing efficiency, pellet quality, and bulk density. Consequently, manufacturers of feeds or feed supplements often prioritize the particle size and uniformity of feed ingredients. However, DDGS product streams are usually characterized by inconsistent particle sizes, posing challenges to uniform drying processes. This inconsistency can lead to difficulties achieving uniform drying, which is crucial for product quality. Additionally, traditional drying techniques for DDGS carry the risk of explosions due to the explosive nature of dust, particularly at high concentrations and temperatures. Moreover, even though drying distillers&#8217; grain opens up a wide range of commercial opportunities, drying requires a lot of energy. With increasing environmental concerns, more companies take issue with the environmental consequences of such energy use and its environmental impact.
How can these issues be solved?
Swedish Exergy knows that DDGS drying is a sensitive process. You can damage the DDGS by adding foul taste by drying with an incorrect process at the wrong temperature with a longer residence time in the dryer. It can also cause burning and/or stripping the DDGS from valuable minerals and proteins that the animals need. Instead, a stable and optimized drying process can improve the product quality, shelf life and nutritious value of the DDGS.
Let us show you what we mean.
The superheated steam dryer for drying DDGS.
Our solution is a closed, pressurized system exposing the wet product to superheated steam. The steam serves as a medium to transport the product within the dryer. The heat from the heating medium is transferred to the steam and suspended product through the superheater surfaces, ensuring no contact between the heating medium and the steam or product suspended in the dryer. This design enables the utilization of various heat sources like flue gas, steam, thermal oil, or electricity for the dryer.
After passing through the loops, a cyclone separates the dried product from the superheated steam. The steam is recirculated while the dried product is discharged through a rotary valve. A portion of the dried product proceeds to the mixer, where it mixes with the wet product. The partially dry mixture is then fed back into the dryer.
The water in the wet product converts into steam during the drying process and is discharged through a pressure control valve to maintain constant pressure. The residence drying time ranges from 5 to 10 seconds. The Exergy Superheated Steam Dryer&#8217;s operating temperature and pressure are optimised to achieve ideal drying conditions, ensuring uniform drying throughout the product.
Optimal solutions.
The DDGS produced when dried in the ExergyPSSD® has an increased value in bypass protein. It undergoes complete sterilization during drying and avoids oxidation due to the lack of air in the dryer. The oxygen-free environment in the dryer also eliminates the risk of fire or explosion. Since the dryer is a closed-loop system, there are no atmospheric emissions, eliminating the need for VOC or odor treatment. Moreover, the ExergyPSSD® is highly energy-efficient, recovering at least 80% of the energy input, resulting in a consumption of only 150 kWh/ton of water evaporation.
The Exergy Superheated Steam Dryer eliminates the current challenges the industry faces.

Question 14

Black pellets – A more effective fuel with Exergy

Accepted Answer

Although so-called black pellets are widely seen as a superior fuel compared to conventional white pellets, their uptake has remained modest. One reason is higher costs associated with production, something that Swedish Exergy and Jalo Biopellets aim to address in a joint project.
With ambitious goals set for reducing greenhouse gas (GHG) emissions, biomass is a go-to renewable energy source. However, untreated, biomass has numerous challenges such as low energy density, high water content, difficulty storing and troublesome handling, therefore, some processing of the biomass before producing energy is necessary for maximizing the benefits.
Biomass pellets are a popular solid biomass fuel type and are usually produced from wood wastes, forestry residues and agricultural residues.
By pelletizing biomass, storage, handling and transportation become easier and more cost-efficient while quality standardisation enables trade.
But the main benefit is the high combustion efficiency when combusted due to the density and low moisture content.

So-called black pellets are seen as a superior fuel compared to conventional white pellets, not least for co-firing with coal or retrofitted coal-fired plants. Some of the advantages of black pellets compared to regular pellets include up to a 30 percent higher volumetric energy density, less sensitivity to biological degradation, and water resistance.

Torrefaction or steam explosion for black pellets

Black pellets are generally produced by first using either one of two processes, torrefaction or steam explosion to treat the feedstock prior to pelleting. In the former, the biomass is heated up to 280-320˚C in a low oxygen environment for a certain amount of time.
Torrefaction is often used as a pre-treatment step for biomass gasification and co-firing of biomass with coal.
In the latter process, the water content, cellulosic sugars and other volatile organic compounds (VOCs) are removed from the biomass to create a solid biomass fuel with similar characteristics to fossil coal.
Either way, the drying of the feedstock is a critical process step that requires energy and as a result, can become a crippling cost item as recent geopolitical events have shown.
Steam drying technology
With steam explosion, pressurized steam at a high temperature followed by a sudden decompression is used to create black pellets.
The process creates a rupture in the biomass fibre rigid structure which leads to an increased heat value, bonding property, bulk density and homogeneity to the biomass. During the process, merchantable biochemicals such as xylitol, furfural and acetic acid can be extracted from the condensate.
As the name suggests, Swedish Exergy’s core Exergy Steam Drying technology uses steam as the drying medium. Steam drying biomass with the Exergy Pressurized Superheated Steam Dryer (ExergyPSSD) provides enhancements such as a steam conditioned product, precise and uniform moisture, an open fibre structure and higher combustion properties as well as having the lowest lifecycle cost.

Commercially proven technology
Superheated steam as a drying medium brings a number of advantages; high heat transfer rate, high energy recovery, no emissions to the atmosphere, no risk for fire or explosion during operation and a short residence time. The technology has been operational in various
agro-industrial, food industry, forest industry, and municipal applications for over four decades. These include pulp- and paper, grain- and beet ethanol, palm oil processing, animal feed, wastewater treatment, and wood pellet plants.
&#8220;For biomass pellet production the bottom-line benefits are tangible and our dryer solution can provide the lowest energy consumption and lowest carbon footprint&#8220;, said Prem Verma, Managing Director, Swedish Exergy AB.
Prem Verma added that enquiries for new industrial applications in other sectors are numerous as energy efficiency and reduced carbon footprints “are fast becoming top of mind in keeping bottom lines in the black.”
Closed-loop system
The Exergy Pressurized Superheated Steam Dryer (ExergyPSSD) consists of a closed-loop system. Where the product i.e the raw material to be dried like sawdust, is conveyed by superheated and pressurised steam as the carrier. The steam is heated through superheated surfaces with either flue gas, steam or thermal oil as the heating media.
The dried product and superheated steam are separated in a cyclone and the steam is recirculated. If the product is very wet, part of the dried product is recirculated back to the mixer where it is mixed with the wet product. Water in the wet product becomes steam in the dryer that eventually can be reused in other processes.
Dutch black pellet project
Swedish Exergy is working together with Jalo Biopellets B.V, a Dutch biomass project developer, to develop a black pellet production facility in the Netherlands. The aim is to produce environmentally friendly fuel in form of black pellets, with little to no residuals while minimizing carbon dioxide (CO2) emissions.
With Jalo’s sophisticated process, a high-quality black pellet with a higher energy content can be produced from a low-quality raw material. A form of energy and residuals cascading takes place along the process steps – from the biomass, black pellets, liquefied food-grade CO2 and heat for the regional heat network which will result in a strongly negative carbon footprint, and additional revenue streams for the project.

The ExergyPSSD is perfectly suited for the project as the closed-loop design eliminates the emissions to the atmosphere. The excess steam produced from the dryer will be used for CO2 capture and district heating, creating negative CO2 as well as extra energy production.
This more than compensates for the energy required to power the dryer. Thereby the ExergyPSSD transforms the drying process, from usually the costliest and energy-demanding stage with the conventional dryers, into the most profitable and energy-efficient process step in the project.
&#8220;Integrating the ExergyPSSD into a black pellet production is easy and results in even better energy efficiency, providing significant savings both for the producer and the environment&#8220;, ended Prem Verma.
The project, which is currently in the final stages before the start of construction has a design capacity to produce 125 000 tonnes per annum of black pellets.

Question 15

We are looking for a project manager!

Accepted Answer

We are now looking for a relationship-building and committed project manager who wants to be part of Swedish Exergy&#8217;s continued growth journey &#8211; together we work to contribute to a more sustainable future!

As a project manager at Swedish Exergy, you will collaborate with the internal project team and external project resources. Your task is to run, engage and coordinate projects from start to finish based on the project budget, schedule and in line with contractual obligations as well as quality and quantity requirements. You are the one who guides and listens in and ensures that all project members have what they need to be able to deliver. The projects are in the process industry, the energy sector, food / animal feed and treatment plants in Europe (Nordic countries, Spain, Germany, the Netherlands, Poland).
 
Is it you we&#8217;re looking for?

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