Synonyms, abbreviations and/or process names
Dust, particles: fine, sticky, hygroscopic
In spray chambers or spray towers water is sprayed or dispersed in fine droplets, normally via sprayers or nozzles at the top of the scrubber, while gas is fed tangentially from underneath – thus forming counter-current flow. Due to the centrifugal effect, there will already be a pre-separation of larger particles in the column. It is also possible to place spray-towers in co-current or cross-current set-up.
High L/G ratios are required to remove fine particles.
Removal efficiency varies between 70 and 99%, depending on particle distribution.
Flow rate: 2 500 -170 000 Nm3/h
Temperature: 4 - 370 °C
In-coming concentrations: 100 -10 000 g/Nm3
Waste water must be treated or discharged into the sewer network.
Residues which must be dewatered and disposed of.
Energy use varies between 0.4 to 2 kWh per 1 000 m3 
For a very basic spray scrubber, investment costs for a to-be-treated gas stream of 10 000 Nm³/h amount to
ca. 50 000 EUR or 5 000 EUR per 1 000 Nm3/h. For other capacities, one should consider a scale-up factor to
the power of 0.3 [1, 2].
- Operating costs
Personnel costs: ca. 0.25 mh/day
Operational costs: 0.4 – 0.5 EUR per 1 000 Nm³ 
Auxiliary and residual materials: The separated dust must be dewatered and disposed of. The water must be
treated prior to being discharged. Transport costs for the separated dust are determined by the type of residue.
Inert: ca. 75 EUR/ton
Chemical: 150 – 250 EUR/ton
Advantages and disadvantages
No risk of fouling or blockage in the washing section
In addition to dust, gaseous particles are also separated
Available in various construction materials
Able to deal with fluctuating gas flows
Low pressure drops
Little space required
Installation type with spray-heads with small openings requires clean washing liquid
Blockages in sprayers could lead to a large yield loss
Not efficient for the removal of fine dust particles
Mass transfer is not very efficient
Is also used as a cooler to quench flue gases.
Spray scrubbers are used in a variety of settings, including:
The chemical industry, to separate dust and aerosols;
The metal industry for various types of waste gases;
Waste incineration installations;
Potato-processing industry for the removal of starch;
Melting processes in metallurgy;
- Factsheets on Air-emission reduction techniques, www.infomil.nl, Infomil
- Common waste water and waste gas treatment and management systems in the chemical sector. BREF document, European IPPC Bureau, http://eippcb.jrc.es
- Elslander H., De Fré R., Geuzens P., Wevers M. (1993). Comparative evaluation of possible gas purification systems for the combustion of household waste. In: Energie & Milieu, 9
- Work-book on environmental measures: Metal and electro-technical industry (1998 ). VNG publishers
- Supplier information
- VDI 3679, Nassabscheider für Partikelförmige Stoffen