NOx in Cement Clinker Production - Experiences Reducing NOx-Emissions

Transcription

1 NOx in Cement Clinker Production - Experiences Reducing NOx-Emissions June 22 st, 2016 Reinhard Beilmann tkis Lima, Peru, Technical Symposium for Reduction of Emissions

2 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 2 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

3 Influence of Fuel-Type on NOX emission values total Calciner Kiln Petcoke, Anthracite Low grade coal High grade coal Oil Lignite Gas Alternative fuels Depending on the quality 3 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

4 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 4 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

5 Thermal NOx Formation in the Sintering Zone simplified Zeldovich Mechanism (thermal NOx) theoretical equlibrium concentrations 5 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

6 Specific NO-Emission Kiln Inlet Thermal NOx Formation in the Sintering Zone -- NO= f(t) Pyrometer Temperature Kiln Outlet 6 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

7 Thermal NOx Formation in the Sintering Zone -- NO= f(o2) 7 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

8 NO emission from calciner NOx Formation in the Calciner -- NO= f(%volatiles) content of volatile matter % 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 relative NOx abatement calciner Optimized conditions for Multi-Stage-Combustion: Best Air Excess value? Air excess MSC air excess number t Residence- time T Temperature no further improvement at very low air excess numbers As published in ZKG, pp , No.2, June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

11 Optimized conditions for Multi-Stage-Combustion: Best Temperature? Air excess Coating formation MSC t Residence- time T Temperature Temperature accelerates the NO abatement pathway 11 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

12 NO 2 (mg/nm³ at Stack) Multi-Stage-Combustion Example of NO - Reduction Measurement tkis 1996 Temperature Calciner 12 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

13 NOx-Reduction (%) by MSC Multi-Stage-Combustion NO-Reduction = f(cfix/volatiles) Cfix/Volatiles 13 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

14 SNCR - Selective Non Catalytic Reduction Secondary Measure for NOx-Abatement Risk of secondary Emissions at higher Reduction levels Increase of CO likely 14 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

15 High Dust SCR Monselice SCR design data: Kiln output: 2400 tpd Gas flow: Nm3/h Temperature: C Stat. pressure: -80 mbar NO X in: 2260 mg/nm 3 NO X out: 232 mg/nm 3 (@ 2.5% O 2 ) NO X stack: 200 mg/nm 3 (@ 4.5% O 2 ) NH 3 -Slip: < 5 mg/nm 3 NH 4 OH 25%: 445 kg/h 15 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

16 NO-Abatement [%] SCR versus SNCR - Performance of NOx Abatement SCR Monselice SNCR NH 3 /NO 16 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

17 NOx and NH 3 concentration in ppmv NOx and NH3 concentration over layers NOx reduction in 1 st layer NOx reduction in 2 nd layer NOx reduction in 3 rd layer 1 st layer 2 nd layer 3 rd layer 17 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

18 SCR: Cleaning Device - Sootblower Raw gas from PH Lance tube Traverse Catalyst layer 18 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis

19 SCR a multipollution reduction technology SCR is not a pure DeNOx technology. It can achieve VOC/THC reduction of minimum 60% Reduction higher with more catalyst installed Methane is not reduced. Hg oxidation HgCl2 is much easier to collect than Hg0 Combination with low temperature GCT recommended SO2 reduction Approx % SO2 is converted in high-dust SCR to sulfates Limitation on SO2 in flue gas only for low-dust applications. NOX reduction by 90% Reduction of NH3 emissions by 90% 19 June 22st, 2016 Formation and Abatement of NOx-Emissions Reinhard Beilmann tkis 19

20 NOx in Cement Clinker Production Experiences Reducing NOx-Emissions Thank you for your attention! Any questions?