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The SWISS COMBI ecoDry is an indirectly heated drum dryer. It dries with superheated steam at atmospheric pressure. The ecoDry technology offers a large energy recovery potential with low emissions and can also neutralize unpleasant odors directly in the dryer.

The ecoDry is based on an indirectly heated drying process with a closed steam circuit (superheated steam) and process-integrated afterburning of the drying vapors.

Drying is thus not carried out in direct contact with combustion gases, but in an extremely gentle manner with superheated steam at low oxygen content.

The exhaust steam generated during drying is heated in the combustion chamber to over 860° C, which oxidizes the hydrocarbons (odor). Through this process, the exhaust gas is released into the atmosphere with low odor and low pollutants.

With an ecoDry from SWISS COMBI, 2 to 40 t/h of water evaporation can be achieved. Drying is possible up to 1% residual moisture.

Various energy sources can be used for drying, such as natural gas, oil or even biogas, hydrogen or biodiesel.

Application areas of the ecoDry

Ethanol industry

The product left over after fermentation is dried into dried stillage (DDGS), a protein-rich feed.

Starch industry

In the starch industry, the residual product is dried into a corn gluten feed, an animal feed for ruminants.

Pectin industry

During pectin production, pomace is generated, which is dried and used as animal feed. With the ecoDry technology, the typical formation of blue smoke (Blue Haze) and the development of odors are avoided.

Advantages of the ecoDry

Water evaporation per dryer

< 40 t/h

Max. Residual moisture

1 %

Systems in operation

>50

High energy recovery potential
Integrated thermal afterburning
Excellent product quality
Low emissions
Low energy consumption
Low fire danger

High energy recovery potential

The ecoDry system from SWISS COMBI has an important advantage in terms of energy recovery. The decoupled process gas has a dew point temperature of approx. 94°C, which means that energy recovery takes place at a relatively high temperature. The decoupled process gas can supply heat to an evaporator or be used in a condenser to produce hot water. The hot water can then be used for heating or, in the case of a belt dryer, to supply heat (see also ecoTwin).

Integrated thermal afterburning

The ecoDry system includes an integrated thermal afterburning system. The decoupled gases are fed into the furnace at the hottest point for thermal afterburning. This destroys the unpleasant-smelling hydrocarbon compounds. The ecoDry technology is therefore particularly suitable for malodorous products.

Excellent product quality

Drying with superheated steam is very gentle on the product, because the steam atmosphere protects the product being dried from burns. The scorching of fine fiber hairs, which is common in drying with flue gas, is almost completely eliminated. As a result, the dried product, especially animal feed, has a very pleasant odor without any burnt traces.

Low emissions

In the ecoDry system, the drying process and heat generation are separated, and heat transfer occurs through a heat exchanger. This approach allows for significantly lower emissions (dust, CO, NOx, volatile organic compounds) compared to a directly heated drum dryer (HTT), thereby enabling compliance with regulations such as the “Technical Instructions on Air Quality Control”

Low energy consumption

Due to the closed steam cycle, we achieve a lower energy consumption of typically 750 to 850 kW per t of water evaporation compared to direct drying. Added to this is the high heat recovery potential.

Low fire danger

In the operational mode of the dryer, an inert atmosphere is created due to the superheated steam, which means that the oxygen content is < 10%. In this condition, the product in the dryer cannot burn, which is highly appreciated by our customers.

Raw materials suitable for the ecoDry.

When it comes to drying, there are often more possibilities than you might think. We design and build systems for various types of raw materials, as listed above. But we can do more. Do you have a new task for us? We would be happy to discuss your requirements with you in order to find the right drying solution for your specific needs.

Call us or send an email to learn more about our products and services

The SWISS COMBI ecoDry is the ideal drying solution for odor-intensive biomass. It dries with superheated steam and has a large waste heat utilization potential of up to 60% of the primary energy used.

Selected References

In its more than 60-year history, SWISS COMBI has already developed and built more than 50 ecoDry drum dryers - in many countries around the world, for many different raw materials, and always with technology tailored to the specific needs of our customers. Each SWISS COMBI plant is individual, each had its specific challenges. You can find out how we mastered them in the following case studies.

Raw Material:

Dried stillage (DDGS)

Country, Year:
South Africa, 2019

Dimensions:

N/A

Water Evaporation:

17 t/h

In this plant, high-quality dried distillers grains with solubles (DDGS) are produced from residues of bioethanol production, with a final moisture content of less than 10% water content. As is customary with ecoDry, odor elimination is integrated without requiring additional energy expenditure.
Raw Material:

Dried stillage (DDGS)

Country, Year:
France, 2019

Dimensions:

N/A

Water Evaporation:

32 t/h

In this plant, the drum and product preparation area was replaced by Swiss Combi. This significantly increased the availability of the plant.
Raw Material:

Dried stillage (DDGS)

Country, Year:
Poland, 2023

Dimensions:

N/A

Water Evaporation:

17 t/h

Having already supplied two ecoDry systems to this customer, heat recovery is now being retrofitted to one of these systems. This involves relatively little effort and enables the amount of energy used to be optimized whilst also reducing costs.
Raw Material:

Corn gluten feed

Country, Year:
Austria, 2017

Dimensions:

N/A

Water Evaporation:

5 t/h

After the delivery of the first ecoDry plant in 2000, we were asked to deliver a second ecoDry plant as a result of a capacity expansion of the plant. The waste heat is transferred to a spray dryer via our condenser.
Raw Material:

Fruit pomace

Country, Year:
Germany, 2019

Dimensions:

N/A

Water Evaporation:

6 t/h

In this plant, an existing directly heated drum dryer was converted into an ecoDry to reduce emissions and utilize waste heat.
Raw Material:

Wheat gluten feed

Country, Year:
France, 2016

Dimensions:

N/A

Water Evaporation:

12 t/h

In this ecoDry plant, the residues of a wheat starch plant are processed into a wheat gluten feed for livestock. This ecoDry has replaced an old drying plant installed in1998.
Raw Material:

Syrup with wheat bran

Country, Year:
Hungary, 2018

Dimensions:

N/A

Water Evaporation:

9 t/h

In this ecoDry plant, syrup and wheat bran are processed into livestock feed.
Raw Material:

Dried stillage (DDGS)

Country, Year:
Netherlands, 2007

Dimensions:

N/A

Water Evaporation:

3 x 36 t/h

In this plant, ethanol is produced in a bioethanol facility for blending into gasoline. The residual byproduct from the bioethanol production is processed using the ecoDry system to produce dried distillers grains with solubles (DDGS), a protein-rich feed for livestock. We have supplied three dryers, each capable of evaporating 36 tons of water per hour.
Raw Material:

Dried stillage (DDGS) from red millet

Country, Year:
Australia, 2014

Dimensions:

N/A

Water Evaporation:

18.5 t/h

In this plant, red millet is used as a raw material for ethanol production. We process the residual product in the ecoDry into DDGS, a protein-rich livestock feed.