Flue Gas Desulphurization in China
Nickel Magazine, November 2005 -- China is in the midst of a massive
industrialization program. Because of this, there is an energy shortage which has resulted in new power
stations being built all over the country – in fact, the equivalent of the entire power generating capacity
of the UK is being built in China each year.
Most of these stations are coal fired and their combustion gases could contribute significantly to an already
severe air pollution problem which exists in much of the country. To avoid this, gases must be cleaned and
the most common way to do this is by installing wet scrubbers which spray limestone slurry into the flue gas
to remove sulphur dioxide by forming gypsum.
This process is known as flue gas desulfurization (FGD) and the environment which exists within the
scrubber and associated equipment such as ductwork and chimney flues is highly corrosive. Stainless steels
and nickel alloys are widely used and the industry now has over 30 years of experience with this
application.
In order to make this experience available to Chinese engineers, fabricators and operators, a series of
FGD Workshops was held in Shanghai, Nanjing, Hangzhou and Beijing during September.
The Nickel Institute coordinated the workshops and gave the overview presentation, but key talks were also
given by stainless steel and nickel alloy producers who are suppling into this field: ThyssenKrupp VDM,
Special Metals, Outokumpu, Allegheny Ludlum and Rolled Alloys.
The four workshops were attended by 110 people representing 51 organizations. Given that power generation
and air pollution control will continue to be major issues in China, it is expected that further such
workshops will be conducted next year.
New Welded Tube Standard
A new standard for welded stainless steel tube, long awaited by the market, has finally come to
light. It is outlined in EN 10217-7, "Welded steel tubes for pressure purposes – Technical delivery
conditions – Part 7: Stainless steel tubes."
The document is an essential reference for manufacturers and users of welded stainless steel tube. The
tubes are used in various applications, some of which involve heat exchangers, equipment for the food
industry, mechanical and civil constructions, chemical-pharmaceutical equipment, and tubes for conduction and
plant engineering.
The new standard, once it has been implemented by all members of the European Community, will replace all
national standards that have applied to this field.
EN 10217-7 will be subject to the procedure for inclusion in the new, harmonized standards under Directive
97/23/EC (PED - Pressure Equipment Directive). This will have an important bearing on the construction of
tube bundle heat exchangers, which are subject to the above-mentioned directive, and on all devices
considered to be under pressure (min 0.5 bar).
In the end, widespread national standards will be replaced with DIN 17457 and NF A 49-147, which were the
references in Europe for quality welded stainless steel tube. The table below, extrapolated from a
publication of the European Steel Tube Association, shows the national standards that will be replaced by EN
10217-7.
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