Examples-reduction of maintenance costs ldentification:-Preventıve Maıntenance cost vs. Non-Avaılabılıty ? � � u - :ii o ... u .. .; .. .. > u .. ı: ı: . .. .. ::ı ı: .. >, ..0 .• C .s: uj w,. İiİ 1 u a 1 -� " il ı;; ! . E E C o � 1 ,ğ ·o � .. ..,. I -' .ll j � ; i � � f .. � E i -i ,( � � � Figııre 3: Example Reduction ofnıaiııteııance costs-Identifıcation Subsequently the actual maintenance strategy and costs were investigated (Figure 4) by analyzing the technical design, the operation mode and the maintenance requirements. Several tools have been used to handle the high amount of data of the CMMS (Computerized Maintenance Management System) and to simulate effects of changing the maintenance strategy. Examples-reduction of maintenance costs-2 Analysıs of Lignıte Handling System LL fu___ fi.ı_L :L ıu_' lı.. Analysis of operation L L • Operotion modos (rcdundont equipmcnt) L • Filling of daily bunkers Analysis of moi ntononco requiromonts • Doily mointononce •Overhouls-overhoul period • ldentificotion of mointenonco cost drivcrs L L L Applied tools: 0oto Anolyzer, SPAR, benchmorking Figııre 4: Exanıple Reducıion of nıaintenance costs-Analysis Result of the investigation (Figure 5) was a new maintenance strategy with lower costs and with remaining availability of the system. The new maintenance strategy combines the operation and maintenance concept. The two lines of the fuel handling system are operated in a way that the utilization of the lines before an overhaul is maximized. Examples-reduction of maintenance costs-3 Conclusion: Cost Reduction by Different Operation Concept { okt: 6 overtuıuls in 3 yura ..,,. f-�--+-----+--- -- ---�-,-- -""� ·---·---- 1..!!! ------- ! ·�=�==�=� .,.. T----+-----lf---- new: 4 overhauls in 3 years t-"" ı----,,ı- --,,,,----=.. ı.l!!! ı---�+---,/-.�.C:::::-.,-+ -F'===�=!�==={ 1 ---- ---· ,�, - reduction of maintenance costs with consistent availability - Figııre 5: Exaıııplc Reduction of ıııaintenancc costs-Coııclusion ARTICLE / MAKALE The second example concerns the reduction of auxiliary power consumption. (Figure 6) of the combustion-air system. The combustion air system in this example is composed of two forced draft fans and two air pre-heaters of the Ljungstromtype. Hot air is re-circulated to the FD-fan and is heating up the air upstream the FD-fan to 40°C. in this case it was identified that due to higher flue gas temperature upstream the air pre-heater the amount of re-circulation air could be reduced without fouling problems in the air pre-heater. The reduction of re-circulation air results in a slight increase of boiler efficiency but more important in a reduction of FD-fan auxiliary consumption due to lower volume and pressure. Examples-reduction of auxiliary power consumption-1 ldentification: Combustion air system Tech nical benchmorking ➔ idea: reduction of recircula1ion air ⇒ red uction offlue gos temperature ⇒ reduction of FD-fan o uxiliory cons. Figııre 6: Exanıple rcductioıı ofauxiliary power coıısum tion-ldentifıcation in the second step the combustion air system was investigated in detail (Figure 7). The fouling behavior of the air pre-heater based on today's coal composition was assessed. The heating surface temperatures were calculated as a function of ambient temperature, flue gas temperature and re circulation air ratio. SO3-dewpoint was checked based on the coal analysis and the respective temperatures. The auxiliary consumption of the FD-fan was calculated by taking the pressure losses and volumes for different ambient air temperatures and re-circulation air ratios into account. Examples-reduction of auxiliary power consumption-2 Analysis. Air preheater and combustion systenı calculalion .•• , 1 ;j ! ı-·,t'-� . ...,, .. . .... . .. ..:.:.:..::,. .. .. •Colculotion of heating surfaco tenıp. dopcnding on ombiont tomp., f l uo gas tcmp., rocirculotion oir •Chcck of SO, dewpoint • Calculotion of pressurc losses and F0 fon ouxiliaıy consumption Appliod tools: Proprielory softwaro far oir-prehootor ond combust i on oir syslom cokulotion Figııre 7: Exanıple rcductioıı of auxiliary power coıısunıptioıı-Analysis As resul! of the investigation a new operation concept for the air pre-heater was developed with lower auxiliary power consumption of the air pre-heater. Depending on the actual ENERJİ & KOJENERASYON OUNYASI 47
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