FLU-ACE condensing flue gas economizer in Tsigrado plant

FLU-ACE condensing flue gas economizer in Tsigrado plant

IMERYS Industrial Minerals Greece Single-Member Société Anonyme

IMERYS Group is the world leader in mineral-based industrial solutions, offering specialized solutions necessary for its customers. IMERYS INDUSTRIAL MINERALS GREECE SINGLE MEMBER SOCIETE ANONYME mines and processes industrial minerals, mainly bentonite and perlite.


Corporate videos & Statements



Objective Action

The project’s goal is two-fold: reduce energy (heavy fuel oil) consumption by an average of  6-7% (also reducing CO2 emissions by 600 tonnes/year), and
b. to produce 0,8 M3/hour water for industrial use

Numbers are as follows:

  • An average of 310 kw of heat is recovered from the exhaust gases of the Tsigrado dryer.
  • Around 0,8 M3/hour water for industrial purposes is produced by cooling the flue gas from approx. 70-80◦ C down to 40◦ C. The total production of water for 4,500 hours of operation is 3,600 M3!

Target Audience

The local community and environment of Milos island, where the company operates since many decades, benefit from the implementation of this method.



The project was launched mid 2015 and after almost two years of R&D studies and preparations, it was first implemented in May 2017.


Big part of the IMERYS plants’ processes in Milos is Perlite and Bentonite Drying through the evaporation of moisture contained in them.

Drying is implemented through industrial Fluidized Bed Dryers consuming heavy fuel oil. Total consumption of heavy fuel oil in IMERYS Milos plants is  approx. 10,000 tons/ year (particularly at the MILOS, Tsigrado perlite process plant, heavy fuel oil consumption reaches 1,500 tons/year).

The idea was to reduce consumption of heavy fuel oil by recovering waste heat from the dryer flue gases and use it to preheat air for the fluidization process (only a 20%  fraction of the total stack exhaust is being  used). Through the same process, water is also being recovered by condensation of the materials’ moisture evaporated and absorbed in the flue gases through drying. Water in Milos is deficient (like in almost all Greek islands of the Cyclades) and is therefore produced locally at a desalination plant.

Following a time-consuming research for the appropriate way to minimize heavy fuel oil consumption, we ended up with the proprietary FLUE-ACE CONDENSING FLUE GAS ECONOMIZER system, “hitting two birds with one stone”, as far as the resources efficiency principle is concerned!

The system started operating in May 2017.

In order to educate young people regarding Resources Efficiency, we plan to organize in 2018 an educational program aiming at introducing the primary and secondary schools of Milos in the idea of recovering heat from a dryer and recovering water from the moisture contained in various materials.

For a more detailed description of the system’s operation, please consult the accompanying presentation: FLU-ACE Photo Presentation.pdf


Impact on Society

The system seems to be working very well, and with the expected positive outcome for the island’s environment.  We plan to install 2 more FLUE-ACE CONDENSING FLUE GAS ECONOMIZERS at the MILOS, Voudia perlite plant, in 2018-2019.

Initiative Location

IMERYs’ Perite Plant in Tsigrado, MILOS

Working with Organization

The system was an exclusively in-house project development and is considered an IMERYS proprietary process.

Workers Participation

In 2017, 4 people have been occupied with the projects implementation and 400 hours have been spent, while the cost for the current year is estimated to approx. 208.000euro.


Benefits for Οrganization

Net present value from the system’s operation is 124,000 euro (depending on current oil prices). In the future, one can count with 3X the aforementioned amount, if two more ECONOMIZERS are installed at the MILOS, Voudia Perlite Plant.

Connection with Global Goals

More Initiatives from Organization

Caring for Our Planet: Imerys Biodiversity Strategy

Contribution to biodiversity through the rehabilitation of Milos mines

Cooperation of companies and groups for the rescue of an employee in Milos – Power through Unity

Creation of a new economic, environmentally friendly activity

Diversity and Inclusion

Endemic, rare, and endangered plant species of Milos – Saving the lost treasure of the island

Eradication of invasive alien plant species from restoration areas

IMERYS’ MILOS PLANT NURSERY as educational destination

Innovative Training of employees in programs that reduce physical strain and improve mental health.

Milos Mining Museum 20th anniversary: an educational center on Milos island

Milos nursery as an educational destination


Pancratium maritimum – An ancient plant returns to the beaches of Milos

Pandemic response plan - Protection of Workers and the Local Community

Relocation of an ancient structure in Milos - Mining goes hand in hand with cultural heritage.

Safe Residents – Tourists and Workers: The traffic management system at the Imerys mines in Milos.

Safer Together: Building a Stronger Health & Safety Culture

Scents and Colors from the Rehabilitated Mines of Milos

Supply Chain: Involving Our Suppliers in Our Long-Term Commitments

Sustainable Development and Corporate Social Responsibility

Take Safety Home: R.S.I. Educational Programs for Imerys Greece SA employees and their children with the collaboration of the Road Safety Institute (R.S.I.) “Panos Mylonas”

YOU@S&B: Your career starts here!

"Let's talk about Fire Safety at Home". Imerys Greece – ELINYAE – Myrtillo cooperation


Εxploit Milos island climate conditions for bentonite drying


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