SULFEROX®

SULFEROX ®
Converting hydrogen sulphide to elemental sulphur
Shell Global Solutions
AT A GLANCE
Customer driver: The need for an effective treatment of
gases containing any level of sulphur
Solution: SulFerox process for the treatment of natural
gas, refinery gas, syngas and other gas streams
Value delivered: Cost advantages in treating gases
containing a wide range hydrogen sulphide levels
Proof point: More than 30 plants worldwide operating
the SulFerox process
Acid-gas treating has traditionally required an amine plant to
remove hydrogen sulphide and a Claus unit to convert the
concentrated hydrogen sulphide stream to sulphur. The SulFerox
process is an alternative to these steps and consequently offers
substantial savings in capital and operating costs by removing
hydrogen sulphide directly from gas streams and converting it
to elemental sulphur.
The SulFerox process was first applied in 1990, and has since
been used worldwide for applications including:
n refinery hydrotreater off-gas;
n a m i n e o f f - g a s;
n refinery process streams;
n coke oven gas;
n primary natural gas treating; and
n associated gas (onshore and offshore).
ABOUT THE TECHNOLOGY
There are numerous methods for reducing hydrogen
sulphide in process streams and each has a specific
application range (Figure 1). Extensive pilot plant testing
and commercial operations show that the SulFerox
process is very well suited for handling gas streams that
yield between 0.1 and 20 t/d of sulphur.
PROCESS DESCRIPTION
SulFerox is a redox-based process that converts the
hydrogen sulphide in sour gas to elemental sulphur
through reaction with aqueous ferric iron. The process
forms solid sulphur particles that are easily filtered out.
There are three steps in the process: absorption,
regeneration and sulphur recovery. During absorption,
the sour gas stream comes into contact with a liquid
containing soluble iron (III), and hydrogen sulphide is
selectively oxidised to form elemental sulphur.
Regeneration involves re-oxidation of the iron (II) to
maintain a supply of active iron (III). To maximise sulphur
recovery, the elemental sulphur formed in the first
reaction is concentrated in a surge tank and then filtered
out. The filtrate is returned to the process for maximum
ferric iron solution recovery.
In most cases, filtration and melting produce yellow
sulphur of a quality comparable to that of conventional
Claus unit sulphur.
Hydrogen sulphide concentration (ppmv)
1,000,000
100,000
10,000
1,000
100
10
0.01
20 t/d sulphur
50 kg/d sulphur
50 t/d sulphur
Non-regenerable
solids and liquids
THIOPAQ O&G
SulFerox
0.1 1 10
Gas flow (10 6 Nm 3 /d)
Figure 1: Hydrogen sulphide processing selection chart.
Amine/Sulfinol + Claus
(+SCOT )
Amine/Sulfinol +
SulFerox/
THIOPAQ O&G

TREATED
GAS
SOUR
GAS
SPARGE TOWER
Figure 2: Typical SulFerox process flow system.
BUSINESS VALUE
The Shell Global Solutions SulFerox process offers a flexible
solution for sour-gas treatment. Operating in the 0.1–20-t/d
sulphur range, the SulFerox process requires less process
equipment and energy to operate than the amine–Claus
alternative (Figure 2).
Removing contaminants from sour streams helps to support
efficient operations and maximise the value of the product
slate. SulFerox is a flexible system that offers several
advantages over conventional systems:
n reduced capital expenditure and lower operating costs;
n flexibility to cope with changes in gas volume and hydrogen
sulphide content;
n effective treatment of gases with very low hydrogen sulphide
concentrations;
DEGASSER
VESSEL
Sulphur-free
fuel gas
SFX SOLUTION
EXCHANGERS
HEATING/COOLING
AIR BLOWER
SFX CIRCULATION
PUMPS
n non-toxic elemental sulphur product; and
n suitability for low- and high-pressure (