With more than 180 plants installed all over the world – the Cellchem sulphur burning plants are one of the most used technologies for production of sulphur dioxide (SO2). Available standard capacities range from 0.5 to 100 metric tons of sulphur burned per day and the design can be tailored to produce several downstream SO2 products. NORAM acquired this industry-leading SO2 – technology from Akzo Nobel (Eka Engineering) in 2013.

The demand for locally produced SO2 is increasing following the more stringent safety considerations related to transportation, storage and use of liquid SO2 applied in many countries. At NORAM we are dedicated to continuing the supply and support of this well proven, reliable and compact Cellchem sulphur burning technology.


Building on its early success in the Pulp & Paper industry, the Cellchem sulphur dioxide technology of today can be applied across a wide variety of industries such as:


  • Feed to chlorine dioxide generators at pulp mills
  • Sulfite and bisulfite solutions
  • SO2-water solutions (sulphurous acid) for pulp souring



  • Feed to cyanide destruction (“detox”) operations at gold mines
  • Leaching of metals



  • Sulfite/bisulfite solutions for waste water de-chlorination
  • Bromine removal



  • Feed to juice sulfitation processes for de-colourization
  • Corn wet milling



  • SO2 gas for sulphuric acid production
  • Inhouse production of SO2 gas as an alternative to purchase liquid SO2


SO2 Plant


NORAM design and supply complete SO2 production units, including but not limited to sulphur melters and storage tanks, sulphur pumps, sulphur burners, SO2 gas quenching equipment, waste heat boilers, acidic and alkaline SO2 absorption towers, compressor system for SO2 gas liquification and mist elimination equipment. For capacities, up to ~10 MTPD sulphur burned, the equipment can be completely modularized (i.e. skid-mounted).


SO2 – production and downstream options

Sulphur Dioxide Technology


If liquid sulphur is available as raw material it is normally the preferred choice as it lowers the investment cost and simplifies the handling.
NORAM can provide design and equipment for both solid and liquid sulphur feed.

Sulphur melting equipment
Sulphur melting can be done in either a sulphur pit or in sulphur melting tanks. Both types are provided with steam coils for melting and heating. The pit or the tank will also function as liquid storage. Feed of solid sulphur to a melting unit can be either automatic or manual depending on the client’s preference.

Liquid sulphur storage
The liquid sulphur is stored in a heated and insulated storage tank at a temperature of 140 – 150 °C, internal steam coils are used for heating. NORAM can also supply unloading stations for liquid sulphur if required.


The Spiral Flame™ (Type SF) sulphur burner was first introduced in 1960 by Celleco of Sweden. Thanks to the novel compact design the Type SF burners only required one third of the space compared to conventional burners.

High-velocity combustion air was introduced tangentially to the combustion chamber, imparting a spiral path to the flame. The turbulence resulted in very effective mixing of the gas reactants, and a downstream afterburner made concentrations above 18 % SO2 attainable without risk of sublimation. A demand for burners with small capacity and compact design led to the introduction of the Cyclone Flame™ (Type CF) burner.

A number of refinements since then have led to the evolution of the current generation of burners.

Today SF burners in the capacity range of 5-100 MTPD of sulphur are standardized. Type CF burners are available in two standard sizes with operating capacity ranges of 0.5-4 and 1-8 MTPD of sulphur respectively.

Both the SF and CF burners can be pre-heated with a variety of fuels including diesel, LPG and natural gas. Owing to the compact design, the burners can be pre-heated to 500°C in as little as 30 minutes, after which firing of the sulphur can begin.




The Spiral Flame™ Sulphur Burner

The Type SF burner consists of the following main parts:

  • Sulphur Gun Station
  • Combustion Chamber
  • After-Burner Chamber


Filtered, molten sulphur is introduced into the combustion chamber in atomized form, by using compressed air. The sulphur gun, as well as the nozzles from combustion air, is specifically located within the combustion chamber to maximize burning efficiency and minimize space.

To react any remaining free sulphur, final combustion takes place in the after-burner chamber. This chamber consists of a bed of inert pebbles creating very high turbulence and an intimate mixing of the gases. Efficient oxidation of the remaining free sulphur is thus assured.

Sulphur Burner



The Cyclone Flame™ Sulphur Burner

Type CF burners consists of the following main parts:

  • Sulphur Gun Station
  • Combustion Chamber


Design principles are the same as for the SF burner and the capacity is easily varied to suit the subsequent processes. The CF burner may be operated manually, or automatically by flow ratio control of liquid sulphur and combustion air. Changing capacity takes only a few seconds and can be effected from the control room.

A plant, based on the CF burner may be supplied as complete, skid mounted units to enable a simplified installation with a compact layout. One unit contains the sulphur melter, filters and sulphur pumps. Another unit contains the CF burner, the gas cooling tower, strainers, pump and cooler for the circulating water. The units have the size of a standard 20-foot container.

Sulfur Burner


Typical flow sheet of an SO2 plant (based on liquid sulphur supply)

SO2 Process


Heat Recovery Boiler
For larger sulphur burning capacities, it is often economical to recover heat formed in the combustion reaction. This is done by passing the hot SO2 gas from the burner through a waste heat boiler, generating steam. The steam produced amounts to approx. 2.8 ton steam per ton sulphur.

Gas Cooling
Hot SO2 gas of approximately 1000-1300° C enters the cooling tower. The tower works without packing and is made corrosion resistant by the use of high alloy material (no brick lining required).The main cooling is done by quenching with sprayed water. Adiabatic cooling by evaporation of water, which saturates the SO2 gas, cools the gas to around 80°C. By addition of external cooling of the circulating water, the gas can be further cooled to 40-50°C, depending on the cooling water temperature.

Gas Absorption
The cooled SO2 gas is normally absorbed in water or reacted with other chemicals. NORAM supplies absorption systems for the following applications:

  • SO2 water
  • Sulphite/bisulphite (caustic soda, soda ash, ammonia, slaked lime, magnesium hydroxide).


Appropriate material selection and extensive experience ensures reliable operation of the absorption systems.

High concentration SO2 gas
The cooled SO2 gas may also be used to produce up to 95 % SO2 gas where the gas from the absorber is fed to a stripping unit supplied by NORAM.

SO2 Liquefaction
The cooled SO2 gas may also be converted into liquid SO2. There are different process options of SO2 liquefaction depending on the economic impact of power and/or chemicals.





Summary – advantages of the Cellchem burners

 High SO2 gas concentration, > 18 %
 Fast start-up
 High turndown ratio
 Available as skid mounted systems
 Extensive reference list, 150+ installations



All inquiries relating to the NORAM Sulphur dioxide technology can be made to:

Henrik Vekselius
Senior Process Engineer
M +46 (0) 721 727 506
D +46 (0) 31 757 40 16

Pernilla Hedendahl
Inventory & Logistics Manager
M +46 (0) 721 727 507
D +46 (0) 31 757 40 17