sPeCIAL ArABAL - ALUMINIUM-Nachrichten – ALU-WEB.DE

ALUMINIUM INdUstry IN the GULf
successful start-up of the fume treatment
centre at ras Al Khair aluminium smelter
J. de Weerdt, P. Klut; danieli Corus
Two FTC’s were built in Ras Al Khair,
Kingdom of Saudi Arabia, as part of the
Ma’aden aluminium complex. These
FTC’s treat the fumes of two anode
bake furnaces that supply anodes to the
740,000 tpy aluminium smelter. FTC 2
was commissioned in October 2012 and
is currently running at full capacity. The
cold commissioning of FTC 1 was done
in January 2013, and hot commissioning
took place in June 2013. As with all startups,
there were some challenges to overcome,
but currently FTC 2 is fully operational
and FTC 1 is running at about 50%
of its capacity because not all fires at the
anode bake furnace 1 are in operation
yet. Both FTCs are performing satisfactory.
FTC 2 performance tests have taken
place in the first week of July 2013.
The Ras Al Khair aluminium smelter project
is a USD10.8 billion joint venture between
Saudi Arabian Mining Company (Ma’aden)
and Alcoa. The aim of the smelter project is
to realise world’s largest and most efficient
aluminium complex with a yearly capacity of
740,000 tonnes. The project’s alumina refinery,
aluminium smelter and rolling mill are located
at Ras Al Khair, 90 km north of Jubail.
The aluminium smelter consists of two potlines
of 360 pots each, using AP37 technology.
There are two anode bake furnaces, ABF 1
having four fires and ABF 2 having three fires,
that produce anodes for the potlines. Both
ABF’s have their own dedicated FTC to treat
the fumes from the fires. FTC 1 consists of
six baghouses and four main exhaust fans (of
which 3 duty and 1 standby) treating the fumes
of ABF 1. FTC 2 consists of five baghouses and
three main exhaust fans (of which 2 duty and
1 standby) treating the fumes of ABF 2. Table
1 summarises the process design data for FTC
1 and FTC 2.
The objective of the FTC’s is to meet the
client requirements in terms of ease of operation,
high online reliability, maintenance
friendliness while performing to comply with
the stringent local environmental legislations
on airborne emissions. The fume composition
and maximum emission levels are listed in
Table 2.
Type of pollutant
the ftC design
Fume composition
[mg/Nm 3 ]
Maximum
emission
[mg/Nm 3 ]
Gaseous fluorides 0 – 200 < 0.5
Particulate fluorides 0 – 50 < 0.6
Total particulates 0 – 200 < 5.7
Condensed soluble tars 0 – 200 < 1.7
Table 2: Fume composition and maximum emission
levels
The most notable achievement in this project
was the short time required for the engineering
and fabrication of both FTC’s. The total time
for the engineering of two complete FTC’s was
only nine months, while only five month after
placement of the purchase orders the first
FTC 2 equipment arrived on site.
Danieli Corus purchased equipment worldwide
and transported it to site in order to meet
the tight schedule. Despite the sometimes
challenging custom clearance, availability of
material within KSA, working pressure and
deadlines that had to be met, all equipment
arrived at site within a relatively short period
of time.
Furthermore, the equipment was supplied
in large module delivery which had a major
impact on site labour requirements since less
site welding was required compared to combining
a series of smaller components. Also,
the complete piping system was prefabricated
in order to reduce site labour required.
This type of modularisation in combination
with the split of responsibilities between
manufacturing and the erection could only
be accomplished with a detailed 3D model
to avoid interferences on site. A detailed 3D
model for both FTC’s was made in which the
Fig. 1: Modular design, left – preassembled baghouse, right – fully fabricated cooling tower
© Danieli Corus
Process Variable FTC 1 FTC 2
Fume volume (Am 3 /h) 245,000 180,000
Fume temperature (°C) 220 220
Underpressure at ABF (kPa) -2,000 -2,000
Number of baghouses 6 5
Number of main exhaust fans 3 + 1 2 + 1
Alumina utilisation (t/hr) 6 4
Table 1: FTC 1 and FTC 2 process design data
Fig. 2: Modular design, left – preassembled stack section in laydown area, right – installation of preassembled
stack section
50 ALUMINIUM · 9/2013