NOx in Cement Clinker Production - Formation and Measures to minimize NOx-Emission

Transcription

1 NOx in Cement Clinker Production - Formation and Measures to minimize NOx-Emission June 22 st, 2016 Reinhard Beilmann tkis Lima, Peru, Technical Symposium for Reduction of Emissions

2 NOx Emissions by Source in EEA member countries (2009) Emissions Cement Plants are contributing to 2 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

3 Development of NO X Limits for Cement Plants in Germany 1500 mg/nm³ 800 mg/nm³ existing plants 500 mg/m³ new plants 500 mg/nm³ 350 mg/nm³ NH 3 =30mg/Nm³ BlmSchV 200 mg/nm³ NH 3 =30mg/Nm³ Nm³ = dry at 10% O 2. Conversion to 10% O 2 permitted in Germany only until June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis 3

4 1500 Emission without Abatement Capability of NOx-Abatement Technologies in Cement Plants mg NOx/m MSC MSC+SNCR SCR June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

5 NOx Sources in the Clinker Burning Process Calciner firing Sintering zone Low oxygen levels Substoichiometric at the ignition zone Flameless oxidation Uniform temperature High temperatures High oxygen levels at the flame N 2 + O 2 2 NO (N O 2 2 NO 2 ) Formation of thermal NOx unavoidable No thermal NO X Fuel NO X only Partly reduction of (kiln) NO X 5 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

6 Measures to influence the NO X emission Theory of Low NOx Burner CO NOx Sintering zone Theory of Low NO X Burner: Reduce flame temperature High temperatures High oxygen levels at the flame N 2 + O 2 2 NO (N O 2 2 NO 2 ) Formation of thermal NOx unavoidable Switch to low reactivity fuel, increase particle size Increase flame length (reduce swirl) Reduce oxygen content Reduce primary air Reduce momentum of primary air 6 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

7 Measures to influence the NO X emission Theory of Low NOx Burner clinker quality Thermal NOx Oxygen Level Options Temperature for lowering the thermal NOx formation in the sintering zone are limited, as clinker quality is always affected. NOx emission should be adjusted in the calciner by MSC Theory of Low NO X Burner: 7 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

8 NOx Development in the Calciner Calciner Fuel N HCN NHi - radicals NOx Air Excess Lack of Air N 2 8 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

9 MSC Multi-Stage-Combustion - A Primary Measure for NOx-Abatement 1. Air excess number below 1 2. High temperature in substoichiometric zone 3. Long retention time in substoichiometric zone top air: ~ 0,85-0,95,lower values possible meal staging for flexible temperature control 3 retention time of ~ 1 second 3 1 Area of reduced combustion condition with flexible temperature control and sufficient retention time Air excess MSC t Retention time T Temperature 9 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

10 Latest References for MSC-Calciner Systems of TKIS < 500 mg/nm³ ~ 500 mg/nm³ 500 mg/nm³ ~ 650 mg/nm³ ~ 800 mg/nm³ Natural Gas RDF Coal (40%) Coal (28 %) Coal (21%)/ Petcoke > 30 units sold 10 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

11 SNCR - Selective Non Catalytic Reduction Secondary Measure for NOx-Abatement 2 NO + 2 NH 3 + 0,5 O 2 2 N H 2 O 2 NO + CH 4 N 2 O 2 N H 2 O + CO Typical Calciner Temperature NH 3 -Slip Ammonia Combustion, NO formation Urea 11 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

12 SNCR - Selective Non Catalytic Reduction Secondary Measure for NOx-Abatement 12 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

13 SNCR - Selective Non Catalytic Reduction Secondary Measure for NOx-Abatement Risk of secondary Emissions at higher Reduction levels Increase of CO likely 13 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

14 SCR - Selective Catalytic Reduction Secondary Measure for NOx-Abatement NO X ~300 C Raw Gas NO X NH 4 OH Storage SCR reactor TiO2 V2O5 WO3 NOx Set point Controller 4NO + 4NH 3 + O 2 4N 2 + 6H 2 O H 2 O 14 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

15 SCR - Selective Catalytic Reduction Secondary Measure for NOx-Abatement SCR Configurations Lowest investment costs Suitable flue gas temperature No interference with main process Easiest option for retrofits - Frequent cleaning of catalyst High Dust (HD) Semi Dust (SD) Suitable flue gas temperature Easier cleaning of catalyst - Higher cost of installation - Complex duct routings in retrofits - Additional power for ESP No dust cleaning required Longer lifetime of catalyst - Highest cost of installation - Requires reheating of flue gas - Complex system - Higher operating costs Tail End (TE) 15 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

16 SCR References / Projects of Elex CemCat Mergelstetten (2010) Rezatto (2014) Monselice (2006) Joppa (2013) Start up of SCR-Systems in 2017: Solnhofen, Phönix, Göllheim 16 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

17 NO-Abatement [%] SCR versus SNCR - Performance of NOx Abatement SCR Monselice SNCR NH 3 /NO 17 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

18 CemCat a Joint Venture of Elex and TKIS (Polysius) Catalysts Preheater / Calciner Industrial References Combustion/Fuels SNCR ESP New products Patents Patents 18 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

19 Conclusion - NOx in Cement Clinker Production Formation and Measures to minimize Emissions Primary NOx Emission can be reduced significantly with modern MSC Calciners down to mg/nm³ SCNR is effective for NOx abatements of 50-60%, further reduction only with secondary emissions, mainly NH 3 SCR abatement is nearly unlimited, secondary Ammonia emissions are not only avoided, but Ammonia is effectively used for the NO reduction High Dust is the favorite solution: lowest investment no extra energy TOC oxidation positive effect on downstream Hg capture 19 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

20 NOx in Cement Clinker Production Formation and Measures to minimize Emissions Thank you for your attention! Any questions?