Download Neurath F and G Set New Benchmarks - Article by Dr. Reinhold Elsen RWE Power and Matthias Fleischmann Alstom Published in Modern Power Systems June 2008 PDF

TitleNeurath F and G Set New Benchmarks - Article by Dr. Reinhold Elsen RWE Power and Matthias Fleischmann Alstom Published in Modern Power Systems June 2008
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Page 1 June 2008 Modern Power Systems 29


As already touched optimised combustion in
the furnace limits NOx formation, as well as CO.

The electrostatic precipitators separate out more
than 99.8% of the dust carried by the flue gas.

While over 90% of the sulphur dioxide from
the flue gas is removed by the FGD plant and
turned into gypsum.

For flue gas desulphurisation, a wet limestone
process is employed.

For process-related reasons, the main wastes
produced by the power plant will be dry and wet
ash as well as gypsum.

Some of the gypsum will be sold to the
construction material industry. But, due to the
inevitable variations in gypsum quality arising
from the strongly fluctuating ash composition,

and due to the likelihood of insufficient demand
from the building sector, some of the gypsum will
be used together with lignite ash for backfilling
the mines from which the lignite will be extracted.

For the other process-related byproducts, it is
planned to re-use them in the power plant.

The calciferous sludge from water treatment,
for example, can be used to reduce pulverised
limestone needs in the flue gas desulphurisation

Water management is another key
environmental consideration. The water needs of
a power plant unit are determined mainly by the
evaporation losses when the heat is discharged
in the cooling tower.

In addition, to avoid any critical salt

concentrations, some of the cooling water must
be continually removed from the cooling cycle
and replaced.

Some of the removed cooling water directly
covers the needs of other water consumers (eg,
the FGD), while excess amounts are directly
discharged into the outfall ditch.

For service water, a purification plant will be
available and the treated water will be released
into the outfall ditch. Any surface water occurring
will be initially collected in a rainwater settling
basin and then released into the outfall ditch.

The minimising of noise has also been a key
objective, requiring all mechanical equipment in
the new units to be installed in enclosed rooms.

Within the units sound-proofing will be used
as required to ensure that levels in the work areas
are well below the permissible values. Low-noise
machinery is being used where possible, but
where it is not possible additional sound-
proofing enclosures or structural partitions are
being provided.

For the air inlets and outlets of the buildings,
silencers are employed. To limit the noise
emissions from the cooling towers, which are

The cooling cycle

Technical data
Bunker volume 50 000 t

Storage capacity 30 h (design)

Overall dimensions 310m x 33m x 23 m

Excavation 605 000 m3

Concrete volume 60 000 m3

Cross section through
underground coal bunker

The excavation for the underground bunker
(Sept 2006), up to 43 m deep in parts

Aerial view of coal bunker, Feb 2008

Summary of key data for Neurath F and G
Location Grevenbroich, Neurath

(near Cologne,

Owner/operator RWE Power AG

Fuel Lignite (domestic)

Cooling system Cooling tower with
natural draught

Installed capacity (MWe) 1100 gross, 1050 net

Net efficiency (%) Greater than 43

Flue-gas waste heat
utilisation (degrees) 350/160/125

Steam generator
Type Once-through, tower

Steam flow (t/h) 2870 (2960 max)

Steam pressure (bar) 272 (280.4 max)

Steam temperature (°C) 600

Furnace capacity (MWt) 2392 (2800 max)

Raw lignite input
(guarantee lignite)(t/h) 820 (1326 max)

Steam turbine
Type STF100

Number of modules (casings) 4

Steam pressure (bar) 259

Steam temperature –
inlet/reheat (°C) 595/604

Speed (rpm) 3000


Rating (MVA) 1333

Power factor 0.825

Frequency (Hz) 50

Terminal voltage (kV) 27

Excitation system Static excitation system

Cooling system Hydrogen plus water

Condensing plant
Circulating water
temperature (°C) 18.2

Condenser pressure (mbar) 48

Tube material Stainless steel

Feedwater heating plant

Number of feedwater
preheating stages 9

Number of feedwater heaters 8

Number of feedwater
deaerating tanks 1

Feedwater inlet
temperature (°C) 292

Main pumps
Condensate extraction
pumps (%) 3 x 50

Feedwater pump 1 x 100 % main turbo
driven feedwater

pump plus
2 x 40% start-up

motor driven
feedwater pumps

Circulating water pumps (%) 2 x 50

Polishing plant Yes

Main transformers
Rated output (MVA) 2 x 1100 (per unit)

Primary/secondary (kV) 420/27

Unit transformers

Rated output (MVA) 2 x 100/60/60
(per unit)

Primary/secondary(kV) 27/10.5/10.5

Standby transformer
Rated output (MVA) 90/45/45

Primary/secondary (kV) 110/10.5/10.5

section turbine



Cooling water Condenser

Water /


Fill packaging

Distribution pipe with
spraying system

Mist eliminator



coal trains



023_030mps0608neur:1 23/5/08 15:29 Page 29

30 Modern Power Systems June 2008


mainly produced by the water falling into the
bottom section, acoustic barriers are being
erected outside them.

Assessments indicate that statutory noise
emission levels in the vicinity of the power plant
will be met comfortably.

Even though it is envisaged that all statutory
environmental requirements for the power plant
will be met by a good margin when F and G start
up, nevertheless the new units have
environmental implications for their immediate
surroundings. Therefore experts at TUV
Anlagentechnik GmbH have assessed the
environmental compatibility of the F/G project.
Backed by individual expert opinions, the impact
on air, climate, soil, water, flora and fauna and,
ultimately, humans, was assessed, as well as the
potential impact on the landscape.

Comprehensive measurements made between
December 2002 and June 2003 recorded the then
existing levels of nitrogen dioxide and airborne
particles (PM10) and included an evaluation of
the heavy metals in the airborne particles and
dustfall at Rommerskirchen-Nettesheim. In the
period December 2003 to June 2004
measurements of prior contamination by
dioxins/furans were carried out. Further prior
contamination data were obtained from
measuring stations operated by the environment
office of the state of North Rhine-Westphalia.

Using the calculation procedures prescribed in
Germany’s TA Luft and supporting wind-tunnel
trials, the additional air pollution from the F and
G units was calculated and the total pollution to
be expected estimated . The results are shown in
the table below.

It can be seen that the additional pollution from

each individual air pollutant is no more than 3%
of the air-quality values of TA Luft and that
overall pollution levels are below the permissible
air-quality values.

The data on existing, additional and total air
contamination apply to the most unfavourable
situation in each case in the region being assessed
and the additional contamination due to the new
units assumes they are emitting at the maximum
admissible levels. Under normal operating
conditions actual emissions would be much lower.

The future for lignite
Looking beyond Neurath F and G RWE Power is
working on the next generation of lignite-fired
power plants. These are expected to offer about a
four percentage point increase in efficiency thanks
to the use of dried rather than raw lignite, as used
in today’s plants, including Neurath F and G.

RWE Power is developing a drying technology
called WTA – fluidised bed drying with internal
waste heat utilization – for this purpose (see Modern
Power Systems, December 2007, pp 17-21

A demonstration facility has been built next to
the Niederaussem BoA unit and commissioning
has just begun. The facility will trial the
technology for the first time in conjunction with
a large-scale power plant, with the aim of
demonstrating that the WTA system in
continuous operation is both technically and
economically viable.

WTA is a proprietary development of RWE
Power and since 1993 it has been undergoing
trials and steady development at Frechen and

WTA technology is also proposed as part of a
major retrofit planned for the Hazelwood power

plant in Australia (see Modern Power Systems,
December 2007, pp 22-29).

It is expected that German electricity demand
will grow only modestly in the coming decades.
Over the past 10 years, consumption has
increased by about 1% per annum.

However, while demand will hardly change,
there are signs of major shifts in Germany’s
energy mix. Above all there is the projected
phase-out of nuclear power – the share of which
in power generation hitherto has been some 22%.
This may be questionable in terms of climate
policy and the impact on the energy sector, but
it has been agreed between the federal
government and the energy sector and potentially
creates a huge generation gap that must be
bridged. If the phase-out happens the nuclear
contribution to annual electricity supply –
presently around 140-170 billion kWh per year
– will dwindle to nothing by 2030.

The German domestic renewable energy
sources – hydro, wind, biomass, landfill gas,
solar, geothermal and waste-to-energy – are at
present making an 11% contribution towards
power generation.

The federal government is pursuing the goal of
increasing the share of renewables in electricity
generation to at least 20% by the year 2020 and
by the middle of the century as much as one half
of all energy is to come from renewables.

Natural gas, too, is likely to enjoy an increasing
share of the power generation market. It already
accounts for around 12% of the total.

The outlook for hard coal is mixed: a decline
in the use of domestically mined fuel and an
increase in the use of imported coal.

But meeting power needs from natural gas,
imported hard coal, and increased electricity
imports creates fewer domestic jobs and less
value added than electricity from indigenous
energy sources such as lignite. It is estimated that
economically mineable lignite deposits in
Germany are sufficient to last for generations to
come. Also, the lignite can be extracted under
competitive conditions and the industry can get
by without subsidy.

Currently lignite fired power plants account for
about a quarter of Germany’s electricity
production, with Rhenish lignite providing about
13% of the total electricity.

Analyses, eg by the Prognos research institute,
have suggested that lignite may even gain in
importance as an electricity source in the long
term future. But this need not be at the expense
of the environment or the climate thanks to more
efficient power plants, as exemplified by
Neurath F and G. MPS

The future: WTA lignite predrying

Expected effect of Neurath F and G on air quality
What percentage of the allowed

air-quality value will be reached after By what percentage does air pollution
units F and G enter operation? increase after units F and G enter operation?

Total air pollution after units
Admissible F and G are commissioned Max. additional

air-quality value (sum of prior and contamination from
under TA Luft added contamination) Prior contamination operating units F and G

Percentage of Percentage of Percentage of
admissible air- admissible air- admissible air-

µmg per m3 air µg per m3 air quality value µg per m3air quality value µg per m3 air quality value

Sulphur dioxide 50.0 7.6 15.2% 7.0 14.0% 0.6 1.2%

Nitrogen dioxide (NOx) 40.0 32.7 81.8% 32.5 81.3% 0.2 0.5%

Airborne particles 40.0 30.1 75.3% 30.0 75.0% 0.1 0.3%

g per m2 and day g per m2 and day g per m2 and day g per m2 and day

Dustfall 0.35 0.114 32.6 % g 0.114 32.6% 0.00002 0.006%

BoA concept BoA concept with predried lignite



Flue gas
+ vapour

1000°C hot
flue gas

Raw lignite

Dry lignite
+ flue gas
+ vapour

Energetic disadvantages:
• drying at very high exergy level
• no use made of vapour energy

Energetic improvement:
• drying at low exergy level (low-pressure vapour)
• use made of vapour energy



Flue gas

bed drier

Dry ligniteCondensate


Heating steam
from turbine bleed

Vapour for boiler
feedwater heating

023_030mps0608neur:1 23/5/08 15:30 Page 30 June 2008 Modern Power Systems 23


Also referred to as BoA 2 and 3, RWE’s Neurath units F and G – 1100 MWe

gross each with efficiency over 43% – use and build on the BoA package

of advanced optimised lignite technologies first used at Niederaussem. Contributors to the high efficiency

include: the largest lignite fired boilers in the world, with the most advanced steam conditions ever achieved

for lignite; advanced steam turbine with titanium last stage blade, coupled to the highest rated two-pole

generator yet built; nine-stage feedwater preheating; waste heat recovery from the flue gas; and optimisation

of auxiliary power needs. A key rationale for the new units is the replacement of old, less efficient, units,

leading to a significant reduction in CO2 emissions, by some 6 million t/y compared with the emissions that

would be produced by the older units in generating an equivalent amount of electricity.

n June 2005, the Düsseldorf regional
government gave its approval for the
construction and operation at the Neurath site
of two lignite-fired power plant units

employing optimised plant technology (BoA).
The Neurath facilities will be the second and third
BoA units (BoA 2 and 3, after BoA 1,
Niederaussem, which went on stream in 2003).

The two power plant units will have a gross
capacity of 1100 MWe each (1050 MWe net) and
a net efficiency of over 43%, similar to that of

The most striking features of the Neurath site
are the two 170 m high buildings for the steam
generators (boilers), which will look much like the
Niederaussem unit, and the two cooling towers.

Neurath F and G set
new benchmarks

Reinhold Elsen,
RWE Power, Essen, Germany and
Matthias Fleischmann,
Alstom, Mannheim, Germany





The existing Neurath plant, left, and, right,
visualisation of the new units, F and G

Location of Neurath

150 MW

300 MW

300 MW

Niederaussem (BoA 1),
1000 MW

Neurath (BoA 2 and
3), 1100 MWNeurath,

600 MW





1960 1980 2000 2009

Efficiency improvements Original schedule for Neurath F and G


Activities 2002 2003 2004 2005 2006 2007 2008 2009 2010

Design studies

Awarding of main contracts

Preparation of request for approval

Detail engineering

Emissions approval procedure 06/20/2005

Levelling & preparatory works

Start of construction 01/01/2006

Construction and commissioning unit F

■ Civil works Jan 2010

■ Erection of 1st boiler column 07/01/2007

■ Start of turbine installation 04/27/2008

■ First ignition 04/05/2009

■ First power generation 07/26/2009

■ Trial run

Construction and comissioning unit G
July 2010

023_030mps0608neur:1 23/5/08 15:27 Page 23

June 2008 June 2008 June 2008 Modern Power Systems Modern Power Systems Modern Power Systems

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