Page 67 - Industrial Plants 2014

Turbine Filter Confguration Flow Rate Initial PD Final PD
Macrogen GT Duo (M5) + Compact Final Filter
A 4,250 m³/h 165 Pa 220 Pa after 5000 hours
(F9)
Coalescer Pads + Bag Preflter (G4) + Com-
B 4,250 m³/h 275 Pa 350 Pa after 2200 hours
pact Final Filter (F9)

gas turbine is 250 MW in size and running for Fig. 3 – Results of the
approximately 5000 hours/year. test and the savings
regarding pressure
drop
Case study 2: Retroft
and upgrade to flter class E11

The following case study will show how it is possible to
increase the efficiency of the gas turbine through a
retrofit of an air intake with EPA (Efficiency Particulate Fig. 4 – Burst final
Air) filtration. filters
For energy operators, the main benefit of an increase in
filter class is reduced fouling of the compressor blades. saving) with the use of Macrogen GT Duo;
Less fouling offers an efficiency enhancement of the • installation of new filter wall system for a dual-phase
gas turbine itself, which has been covered extensively compact filter F9 and E11 mounted together (figure
in previous publications. 6);
However, a normal retrofit with EPA filters will see an • relocation of anti-icing duct to free space for three
increase in pressure drop brought about by the switch more filter units;
to a higher filtration grade. The following case study will • new silencers – change from aluminium to stainless
demonstrate how it is possible to carry-out such a steel (figure 7);
retrofit without increasing the pressure drop of the filter • sealing and painting of the air intake (inside and
system. outside);
The German power plant in this case study had • replacement of the coupler;
experienced problems with final filters supplied by an • rebuild of the roof construction.
international filter manufacturer. In fact, 20% of the final
filters installed were damaged as a result of high Results of Case study 2

moisture, dust and low burst pressure of these final The air intake retrofit allowed an upgrade in filter class
filters (figure 4). to E11 and a switch to three filter stages with an initial
Experts of Mann+Hummel Vokes Air began with a pressure drop increase of just 20 Pa. Main benefits for
survey and full analysis of the gas turbine, preparing a the operator are:
solution that optimised the entire air intake – from the • reduced dust penetration to the turbine of
weather hood to the silencers. The chart of figure 5 approximately 10 g/year, operating 8000 h/year
shows the before and after of the retrofit actions. (PM10) with the related efficiency enhancement of
The scope of supply of the retrofit included: the gas turbine;
• new weather hood with improved performance: • filter life of stage 1: one year;
from 30 Pa to 10 Pa; • filter life of stages 2 and 3: from two to three years;
• removal of separate droplet separator (150 Pa • on- and off-line washing unnecessary.

Based on 3,500 m³/h per flter Init. Pressure Drop [Pa]
Original After Retroft
Weather Hood / Bird 30 10
Grid
Droplet Separator 150 -
G4 Bag Filter 65 -
Stage 1
G4 Macrogen GT Duo - 65
F8 Compact Filter 90 -
Stage 2
F9 Compact Filter - 100
Stage 3 E11 Compact Filter - 180
Fig. 5 – Before and
Total initial Pressure Drop: 335 355 after retrofit actions

IndustrIal Plants - May 2014
63