ExergyPSSD® for efficient drying
Dry high‑moisture solid materials in seconds while maximizing energy recovery and eliminating process emissions to atmosphere, delivering efficient, low‑carbon drying performance across a wide range of industrial applications.
Dry high‑moisture solids in seconds, maximize energy recovery and cut emissions, delivering efficient low‑carbon drying for a wide range of industrial applications.
High‑performance drying with ExergyPSSD®
The ExergyPSSD® is a pressurized superheated steam dryer for continuous drying of solid materials such as paper pulp, sawdust, wood waste, animal feed, peat, sludge, agro biomass and various industrial by‑products. Instead of hot air, it uses superheated steam as both transport gas and drying medium in a fully closed loop, enabling very short residence time, uniform final dryness up to 99.9% dry solids and highly efficient heat recovery into surrounding processes.
Reliable for demanding materials
Originally invented at Chalmers University of Technology in Gothenburg in the late 1970s, the ExergyPSSD® has been successfully implemented across a wide range of industries worldwide. Used for decades to dry challenging materials such as paper pulp, sawdust, wood waste, animal feed, wet distillers’ grain, peat, sludge, tea, agro biomass, bagasse and sugar beet pulp, it offers reliable, continuous industrial operation with a long life-cycle and low maintenance needs—making it ideal for biomass, pulp and paper, feed, food and waste applications that challenge conventional air dryers.
In the ExergyPSSD®, the wet feed enters a closed, pressurized dryer where it is exposed to superheated steam heated by flue gas, steam or thermal oil. The air‑tight feeding system brings the product into the steam atmosphere, where the steam acts as both conveying gas and drying medium, rapidly evaporating moisture in just a few to 15 seconds. Dried product and steam are separated in a high‑efficiency cyclone, the dry solids are discharged through an air‑lock, and the steam is recirculated and reheated, while a controlled amount of excess steam is released via a pressure control valve. For very wet materials, part of the dried product can be recirculated and mixed back with the wet feed to stabilize operation and improve handling.
Water initially contained in the product is converted into secondary steam, which can be recovered and supplied as useful energy to surrounding processes.
The ExergyPSSD® continuously dries solid materials such as pulp, biomass, animal feed, sludge and wet waste in a closed, pressurized steam loop with very short residence time and final dryness up to 99.9% dry solids. With no process air it has essentially no emissions, while efficient steam recovery, few rotating parts and a compact design enable low‑maintenance operation and easy integration with CHP plants, evaporation systems, process heating loops or district heating grids.
Superheated steam drying allows you to turn the moisture in your feedstock into a valuable energy source, with more than 95% of the drying energy recoverable for reuse when the steam is properly integrated. Recovered steam can typically be used for:
- Process heating in pulp, paper or food lines
- Evaporation and distillation in chemical or biorefinery processes
- ORC or steam turbines for power generation
- District heating or local heat networks
Drying in an oxygen free steam atmosphere eliminates oxidation and significantly reduces the risk of fire and dust explosion compared to air dryers. The short residence time and controlled temperature profile preserve sensitive components, improve color and nutritional value in many products, and prevent quality degradation. Additional benefits include:
- Sterilization of the product due to pressurized steam conditions
- No odor laden exhaust gases thanks to the closed loop without air
- Condensate streams that can be collected and treated separately
The ExergyPSSD® is suitable for a wide range of bulk solids, fibrous materials and slurries, as long as the product can be properly contacted with the circulating steam. Typical application areas include:
- Biomass and biofuels: sawdust, wood fiber, wood chips, bark, peat, agro biomass, bagasse, pellets, briquettes
- Pulp and paper: paper pulp, fiber sludge from wastewater treatment and other fibrous residues
- Animal feed and food side streams: wet distillers’ grain, sugar beet pulp and other high moisture feed ingredients
- Sludge and waste: municipal sludge, industrial sludges, wet solid waste, filter cakes
For very high moisture contents or challenging products, the ExergyPSSD® Superheated Steam Dryer can be combined with an Exergy Air Stream Dryer in a two-stage configuration to further optimize energy use and product handling.
In the ExergyPSSD®, the wet feed enters a closed, pressurized dryer where it is exposed to superheated steam heated by flue gas, steam or thermal oil. The air‑tight feeding system brings the product into the steam atmosphere, where the steam acts as both conveying gas and drying medium, rapidly evaporating moisture in just a few to 15 seconds. Dried product and steam are separated in a high‑efficiency cyclone, the dry solids are discharged through an air‑lock, and the steam is recirculated and reheated, while a controlled amount of excess steam is released via a pressure control valve. For very wet materials, part of the dried product can be recirculated and mixed back with the wet feed to stabilize operation and improve handling.
Water initially contained in the product is converted into secondary steam, which can be recovered and supplied as useful energy to surrounding processes.
The ExergyPSSD® continuously dries solid materials such as pulp, biomass, animal feed, sludge and wet waste in a closed, pressurized steam loop with very short residence time and final dryness up to 99.9% dry solids. With no process air it has essentially no emissions, while efficient steam recovery, few rotating parts and a compact design enable low‑maintenance operation and easy integration with CHP plants, evaporation systems, process heating loops or district heating grids.
Superheated steam drying allows you to turn the moisture in your feedstock into a valuable energy source, with more than 95% of the drying energy recoverable for reuse when the steam is properly integrated. Recovered steam can typically be used for:
- Process heating in pulp, paper or food lines
- Evaporation and distillation in chemical or biorefinery processes
- ORC or steam turbines for power generation
- District heating or local heat networks
Drying in an oxygen free steam atmosphere eliminates oxidation and significantly reduces the risk of fire and dust explosion compared to air dryers. The short residence time and controlled temperature profile preserve sensitive components, improve color and nutritional value in many products, and prevent quality degradation. Additional benefits include:
- Sterilization of the product due to pressurized steam conditions
- No odor laden exhaust gases thanks to the closed loop without air
- Condensate streams that can be collected and treated separately
The ExergyPSSD® is suitable for a wide range of bulk solids, fibrous materials and slurries, as long as the product can be properly contacted with the circulating steam. Typical application areas include:
- Biomass and biofuels: sawdust, wood fiber, wood chips, bark, peat, agro biomass, bagasse, pellets, briquettes
- Pulp and paper: paper pulp, fiber sludge from wastewater treatment and other fibrous residues
- Animal feed and food side streams: wet distillers’ grain, sugar beet pulp and other high moisture feed ingredients
- Sludge and waste: municipal sludge, industrial sludges, wet solid waste, filter cakes
For very high moisture contents or challenging products, the ExergyPSSD® Superheated Steam Dryer can be combined with an Exergy Air Stream Dryer in a two-stage configuration to further optimize energy use and product handling.