Flue Gas Desulfurization

Valmet Flue Gas Desulfurization

Valmet Flue Gas Desulfurization (FGD) is an efficient and reliable solution for SOx removal. You can also get this system combined with NOx removal, making SOx and NOx removal more economical. Limestone or lime powder is used to absorb sulfur that is converted into gypsum slurry in an open spray tower absorber. NOx is reduced by adding an oxidant to the flue gas stream. After dewatering, the slurry is converted into gypsum – an easily manageable end product that is a suitable raw material, for example, for the wallboard and cement industries.

Over 95% sulfur removal

Possibility to combine SOx and NOx removal

Low lifecycle cost

Proven reliability

Simple, economical design for a wide range of plant sizes and fuels

Valmet Flue Gas Desulfurization system is applicable for power plants in a wide size range from small to medium (20-250 MWe). It features a cost-efficient design in which a multi-inlet absorber can be shared by several boilers or engines. Thanks to its simple and economical design, the equipment can easily be retrofitted to a power plant even during operation.

Valmet’s FGD process has successfully been used in power plants that run on various fuels including coal, heavy fuel oil and Orimulsion. We also have a strong track record in rebuilding and modernizing existing FGD systems to emission compliance as well as to extend plant life.

Depending on fuel composition and available water quality, the FGD system can be designed to produce no wastewater during operation. The process has no impact on fly ash.

Gypsum as a by-product

The process uses limestone or lime powder to absorb sulfur from flue gas. The sulfur is converted into gypsum in an open spray tower absorber. Gypsum slurry is dewatered into an easily handled by-product that is suitable as raw material, for example, in the wallboard and cement industry.

Case CIECH Soda Polska soda plants, Inowroclaw and Janikowo, Poland

Valmet’s FGD system allows both soda plants to operate their coal-fired boilers with minimal SO2 emissions. A highly reliable design combines flue gas from all boilers to a common FGD. This makes it an economical and space-saving solution to customers with limited space availability. The Janikowo soda plant has the additional benefit of using in-house waste from semi-dry FGD as a reagent in the Valmet’s wet FGD system. This both saves reagent costs and eliminates waste disposal costs.   

Delivery in 2017 and 2018


  • Wet limestone FGD for four coal-fired boilers type OP-110
  • Wet limestone FGD for two coal-fired boilers type OP-140


  • <100 mg/Nm3 SO2, <10 mg/Nm3 dust
  • High-quality gypsum production

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Our expertise is at your service

Our expertise is at your service

Our focus is to bring your performance forward. Our expertise in sustainable energy production and emission control is at your disposal. Get in touch with our specialists through your local Valmet office, or the link below.

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