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High-Dust SCR Technology
Operational Experience with Catalytic NOx Abatement
7th International VDZ Congress 2013Düsseldorf, 26 Sept 2013
Detlef EdelkottSchwenk Zement KG
• Aug 2008 - Application for permission and subsidies
• Oct 2008 - Purchase agreed
• until Mar 2010 - Planning, delivery, erection
• Apr 2010 - Start-up
• since May 2010 - Testing & optimisationsupported by in-depth research by VDZ
Project phases
Project Phases
Description of the SCR installation
Exhaust gas system with combined SCR and SNCR
NH3-injection for SNCR
NH3-injection for SCR
SCR
ID Fan
Catalyst
specific requirements:
• fit for high dust contents
• sustainable activity
• low oxidation rate SO2 to SO3
• chemically and mechanically stable
• low pressure drop
Description of the SCR installation
6m
6m
blower
Scheme of a Catalyst Layer Cross-Section
18 catalyst modules
Description of the SCR installation
• Apr. 2010 Initial start-up with three active layers in hexagonal honeycomb-design (L = 1.3m) installed and a dummylayer on the top
• Jul. 2010 Active catalyst layer (L = 0.6m) added in place ofdummy layer
• Feb. 2011 Bottom layer replaced with new square grid design layer (L = 0.9m)
• Nov. 2011 Middle layers replaced (1 new, 1 regenerated)
• Sept. 2012 Top layer replaced (regenerated)
• Jun. 2013 Repair of both regenerated layers
Changes of configuration of SCR
Operational results since refit Nov 2011
448 days clinker production411 days SCR operation 92 % availability
Operational costs of SCR
Investment and operational costs
- Catalyser replacement
- NH3 consumption24.9% Ammonia solution or 40% urea
- Power consumption
Influence of injection location on reduction agent consumption
Investment and operational costs
refitting ofSCR, SNCR
onlycombinedSCR/SNCR
SCR only
Conclusion• High-Dust SCR is feasible and effective –
emission limits of 200 mgNO2/m³ and 30 mg/m³ NH3 can certainly beachieved. The compressed-air cleaning system must be properlylevelled and maintained
• Availability approx. 92% in 2012 – 100% availability should beachievable
• Deactivation time has been unsatisfactorily low –longer life-cycle is expected with limitation of operation temperature bywater injection into the downcomer (less than 380°C)
• Regenerated catalyser elements were seen to suffer a decrease in mechanical resistance (erosion of weakened elements)
• Injection of either Urea or Ammonia solution show comparable results
Conclusion