920-01-637/1.000/04.2017

Highly efficient performance, robust and reliable design

Advanced Process Solutions

EKATO Agitators for Flue Gas Desulfurization

EKATO FGD AGITATORSRMTEKATO the world market leader in mixing technology
Since 1933 EKATO is successfully designing and manufacturing industrial agitators utilized in all process-oriented industries.
More than 250,000 agitators are operating worldwide in various industrial applications.

Advanced Process Solutions

EKATO has been family-owned since its founding in 1933 and is represented worldwide with subsidiaries in Europe, Asia, Australia,
South America, South Africa and the USA as well as a network of trading partners.
In the ultramodern research and development center at EKATO‘s headquarters, more than 1,000 m² of laboratories and testing
facilities are available for analyses of customer processes. EKATO provides German engineering with the highest quality
standards for manufacturing "Made in Germany".
A complete service package with database-supported spare parts and maintenance management, a worldwide 24-hour service hotline
and comprehensive service range that covers start-up, modification and modernization up to process optimization complete the offer.

EKATO in FGD plants since 1979
Since 1979, when the FGD market rose in Europe and the USA due to more stringent emission limits, EKATO equips coal fired power
plants with agitators specifically designed for the extreme demands on the equipment and set the benchmark for todays used technology.
With more than 12,000 agitators sold worldwide, EKATO is the No.1 agitator supplier in this market.

During the first years of the 1980s, the absorber tower of an FGD plant was generally equipped with a sparger grid to inject the oxidation air
into the process. The little outlets of the pipes were easily plugged by the solids and led to significant investment, repair and maintenancecosts.
Under this aspect EKATO developed in 1983, with numerous lab tests up to operational scale, the agitator gassing system with the oxidationair-lance placed in front of the impeller. With this new development EKATO set the first benchmark on the FGD market. Nowadays more than
90% of all modern FGD plants worldwide are using this kind of agitator lance system.
One other big challenge in the FGD process is the high abrasion on the impeller blades forced by high solid concentration and flue ash. Extending
the lifetime was the goal for developing the EKATO WINGJET impeller. In 1994, EKATO discovered the innovative approach in the aircraft
construction. At the wingtips of modern jets, you will find a so called winglet. Inspired by that, the EKATO WINGJET has a winglet at eachblade which suppresses the vortex created by the pressure compensation at the blade tips, the main reason for abrasion.
This impeller design still remains the benchmark for todays FGD agitators.

process water

Simplified
process
flowchartofofaawet
wetabsorptionabsorption planta dual-circuit
absorber
Simplified
process
flowchart
plantwithwitha dual-circuit
absorberThe process
More than 90% of all desulfurization plants worldwide are using the wet desulfurization process, because of the absorbents lime andammonia availability and the fact that the product of the wet process can be further utilized or easily disposed.
The sulfur dioxide (SO2) contained in the flue gas is absorbed chemically in an aqueous washing suspension of limestone (CaCO3), quicklime(CaO) or slaked lime (Ca(OH)2) and afterwards oxidized with atmospheric oxygen O2 in a series of steps to produce gypsum (CaSO4).

Advanced Process Solutions

Agitation technology
Vertical (top entry) agitators are mainly used for suspending the solids during the preparation stage of limestone and for dewatering thegypsum. A number of horizontally mounted (side entry) agitators are generally operating at the absorber tower. The structural conditionsof an absorber tower mostly limit the installation of vertical (top entry) agitators.

Suspension
The horizontally mounted agitators installed around theabsorber tower will maintain a complete and reliable offbottom suspension. Any sedimentations inside the absorber sump formed by gypsum particles have to be avoided
to achieve a continuous operation of the absorber tower
without any interruptions.
This will be achieved by optimal angular adjustments,
both vertically (α) and laterally (β), plus strategic placement of the agitators around the absorber.
Without the correct angle adjustment and too much
distance between the agitators, sediments can occur inthe center of the vessel or on the vessel wall which canlead to plugging of the pump nozzles. The ideal angle
adjustment depends on the scale.
Based on numerous CFD (computational fluid dynamics)
studies, lab tests in our modern R&D center and provenin more than 1,500 FGD plants, we have the know-how
to calculate and provide the right agitator setup for eachabsorber, to prevent the solids building sediments andguarantee a reliable operation.

Effect of the mounting angle of side-entry agitators on sediments

EKATO’s highly advanced R&D centerIn our over 1,000 m² Research & Development Center we offer services
for lab and pilot tests, the scale-up to production scale and flow simulation (CFD) for design basis and process optimizations.
The basic engineering for the main components, of agitators and complete
vessels (with nozzles, baffles, gas-pipes etc.) is based on state-of-the-art
tools like the Finite Element Analysis (FEA).

FGD lab-absorber in EKATO‘s R&D center >Gassing
The agitator lance gassing system developed by EKATO represents a substantial optimization compared to crossed-pipe gassing. This system
consists of one air lance placed within the jet stream created by the impeller to insert the oxidation air. The air gets dispersed into fine bubbles
by the high flow velocities of the impeller. These air bubbles are distributed over the entire cross section of the vessel. This EKATO agitator
lance gassing system soon became the standard in wet limestone FGD processes as it offers great advantages.

Advantages of the EKATO agitator lance gassing system:- Highly efficient oxygen mass transfer which reduces the amount of oxidation air required by up to 30% compared to sparge grid
gassing systems. The fine bubbles which are produced by the high flow velocities, have an extremely large aggregate surface area,
creating a much more efficient oxygen mass transfer than a bubble column with large bubbles.

- Long bubble residence time: Most of the sparge grid gassing systems insert the air at a level above the agitators. The EKATO agitator
lance gassing system inserts and distributes the oxidation air at a much lower level. Better coverage over the entire cross section of thevessel and an extended residence time due to the smaller bubbles enhance the oxygen utilization.

- Minimum installation costs thanks to significantly less piping in the vessel.
- No risk of clogging: The large pipe openings are very unlikely to clog up. As a result constant efficiency of the oxidation air dispersion
in continuous operation as well as lower maintenance costs are achieved.

Agitator design
The agitators are designed and manufactured for fatigue strength, based on rated motor power and maximum dynamic loads.
The reliability of these agitators is proven by over 1,500 FGD plants, under the severe process conditions in long term operation.

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Advanced Process Solutions

EKATO HWL-N side entry agitators
The most common agitator for absorber tanks worldwide
with reliable V-belt drive that guarantees a smooth operation.
Motor powers up to 90 kW are available for small and large
absorber tanks >Ø 25 m

2

The unique CFD optimized impeller blade geometry offers
following advantages:- Maximized efficiency- Bundled axial flow & increased pumping capacity- Winglets suppressing the tip vortex for reduced impact corrosion

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The EKATO WINGJET is constructed of highly corrosive and abrasive
resistant Super Duplex materials that enable longer operational life andreduced maintenance costs.

1 EKATO WINGJETThis impeller with an integrated wear resistance has been speciallydeveloped for the use in absorbers of flue gas desulfurization plants.
Available in diameters: 800 — 2000 mm
2 EKATO shut-off device
The shut-off device guarantees servicing or even replacing the mechanical seal
during normal operation conditions and without emptying the absorber tower.
3 EKATO ESD 42L
This single-acting product lubricated mechanical seal is particularly designed
for the FGD application with highly abrasive and corrosive products providing
long lifetime and easy maintenance on-site.
4 Agitator drive
Our agitators are driven by strong and reliable drive units customized forthis application. Depending on the requirements the following drive systems
can be offered:- Industrial gearboxes with reinforced bearings- V-belt drives- Bevel gearboxes

Propeller

WingjetAbrasion on impeller bladesQuality ”Made in Germany”
In addition to decades of expertise in FGD processes, EKATO provides an optimum mechanical design, the highest quality standards for
manufacturing “Made in Germany”, a competent and flexible after sales service with rapid response as well as a certified quality
management according to ISO 9001.

1EKATO HWL-A top entry agitators
The agitator for small and large tanks in FGD plants,
motor powers from 3 to 160 kW, shaft lengths
from 1 to 20 meters.

1 Agitator drive2

Industrial gearboxes designed according to thelatest DIN and ISO standards to guarantee long
lifetime and reduced maintenance.
2 Product wetted material

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Product wetted parts supplied for FGD applications
made of rubber lined carbon steel, stainless steelor nickel-based alloys.
3 EKATO shaft design
The shafts are designed for maximum
hydraulic forces, bending moments andtorque to ensure the most reliable operation.
4 EKATO sealed hub
A unique hub design that does not require on-site
welding or rubber lining.
5 EKATO VISCOPROP
The advanced hydrofoil impeller with excellent
axial flow velocities provides best solid suspension
even at high solid concentrations,no matter if off-bottom or homogeneous
suspension is required.
Features:- Single/multistage arrangement- Two- or four-bladed impellers- Variable blade angles- Diameters up to 6,500 mm

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Worldwide over 12,000 EKATO agitators prove their reliability
every day in more than 1,500 flue gas desulfurization plants.
As the world market leader EKATO set the benchmark in
nowadays state-of-the-art FGD agitator systems.

EKATO
Rühr- und Mischtechnik GmbH
Hohe-Flum-Str. 37
79650 Schopfheim
GermanyTel. +49 (0) 7622 29-0
Fax +49 (0) 7622 29-213
E-mail: info@ekato.com• More than 80 Years of Experience• High Developed and Proven Equipment• Reduction of Power Consumption• Highest Equipment and Process Availability

EKATO
Side Entry Agitators
for FGD Absorbers

EKATO VISCOPROP
2-bladedwww.ekato.com

920-01-637/1.000/04.2017

EKATO VISCOPROP
4-bladed