Semi-dry desulphurization

Purification of acidic harmful gases

The semi-dry desulphurisation process is particularly suitable for systems up to 1 million Nm3/h flue gas. To purify the gases from SOx, but also from other acid components like HCl and HF, an aqueous absorbent (e.g. lime slurry) is injected into the spray absorber. The acidic harmful gases react with the absorbent to form salts, while at the same time the water in the suspension evaporates and the flue gas cools down before leaving the absorber.

The reaction product is usually separated in a downstream fabric filter, while a partial flow can be circulated for better utilization. By gas cooling and increasing the gas humidity the process is also positively influenced. The separate control of water and absorbent enables the ideal operating point to be set by adapting the cooling and absorption ratio to the pollutant load of the flue gas.

Semi-dry desulphurization

Our solution

For the injection of lime slurry we recommend our twin-fluid nozzles with a large free cross-section, which are resistant to clogging. Due to the very fine droplets and the high penetration depth, the process can be operated more efficiently and thus the demand for absorbent can be significantly reduced. With the right choice of material, wear can be reduced even with abrasive media and use at high temperatures is possible.

Together with the injection system, we offer you the optimum solution for your process requirements. Our online cleaning system enables a reliable and cost-optimized operation of the injection system by cyclic and automated cleaning of the nozzle lances. These systems are also suitable for the replacement of rotary atomizers.

Corresponding products

1SR nozzle lances

Twin-fluid nozzles for semi-dry desulphurisation

For optimum flue gas desulphurisation

The Lechler 1SR nozzle series has been specially developed for the atomization of lime milk or suspension.

Learn more Technical data (pdf, 3.32 MB)
Lechler Online Cleaning (LOC®)

Lechler Online Cleaning (LOC)

Comfortable cleaning-in-place system for twin-fluid nozzle lances

Removes damaging deposits and cloggings in nozzles, nozzle lances and pipelines and makes your system more economical.

Learn more Technical data (pdf, 3.32 MB)

Professional reports

Multi-pollutant control technology assessment: Circulating fluidised bed scrubber vs. spray dryer absorber
Sprühtrockner − Sprühabsorber
Sprühtrockner − SprühabsorberBuch "Energie aus Abfall, Band 11", TK Verlag Karl Thomé-KozmienskyArmin MöckRead now (pdf, 3 MB)
Spray technology is critical in helping a plant achieve optimal performance
Spray technology is critical in helping a plant achieve optimal performanceASME Power Conference 2009, Albuquerque (New Mexico), USARobert E. Van Durme, P.E.Read now (pdf, 450 KB)


Armin Möck, Key Account Manager, Lechler GmbH, Metzingen
Armin MöckKey Account Manager | Lechler GmbH, Metzingen (Germany)Phone +49 7123 962-319armin.moeck(at)

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