Field measurements of mercury and SO 3 from the Fabric Filter at the Callide Oxyfuel Project during Air-Oxy Transitions

Transcription

1 Field measurements of mercury and SO 3 from the Fabric Filter at the Callide Oxyfuel Project during Air-Oxy Transitions Rohan Stanger* a, Timothy Ting a, Lawrence Belo a, Chris Spero b, Terry Wall a a University of Newcastle, b Callide Oxyfuel Project 5 th Oxyfuel Combustion Research Network Meeting Wuhan, CHINA 29 th October 2015

2 ANLECR&D Research areas at COP to reduce cost and risk Fabric Filter (not ESP) NaOH Polishing (not FGD) SO3 formation acid dew point corrosion + temperature Hg capture affected by oxy-conditions or carried to CPU Hg oxidation uncertain SO2 capture ph and NaOH usage in high CO2 SO2/NOx reactions (N2O) in CPU Removal of Hg 2+? Compression (no AC bed) NOx capture in CPU kinetic reaction to NO2 or emitted as NO stability of condensates Hg capture in CPU dependant on NOx product identification and stability risk to brazed Al-HEX cold box

3 The Callide Oxyfuel Project Retrofit Picture courtesy of Yamada, IHI APP Oxyfuel Course % Hg captured in fly ash ~70% Hg 2+ in flue gas To CPU No desox / denox / de-hg All impurities sent to CPU Hg results from Macquarie Uni Trace Impurity Study, Nelson 2012

4 Transition Schedule and associated measurements MONDAY 30/06/14 TUESDAY 1/07/14 0:00-6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 0:00-8:00 10:00 12:00 14:00 16:00 18:00 OXY Mode AIR Mode 5 10 Sampling interval Ash Samples taken Low NOx burners used Original burners used

5 Transitions between air-oxy modes occur without CO2 capture All flue gas to stack (except recycle) no CPU Real oxyfuel emissions Ideal time for studying Hg behaviour under changing O2

6 Heated Lance for SO3 and Total Hg (30 minute interval sampling during transitions) 2 heated zones Collects 1 SO3 + 2 Total Hg samples 10 minute change-over

7 Non-heated lance for continuous Online Hg Designed with manual switch between Hg total and Hg 0 In practice SnCl 2 not responsive enough for Hg total Ohio Lumex 915+ Hg analyser 1-20,000ng/m 3 Hg in real time

8 Probe Assemblies Heated Probe gas conditioning Online Hg Probe gas conditioning with PFA switches PFA sampling tubes with AC beds

9 Location on stack and sampling equipment

10 Hg measurements with original burners sampling interval (as Hg 0 ) OXY AIR

11 Hg measurements with Low NOx burners (2 out of 4 burners) (note change in scale from previous slide, was 5µg/m 3 ) (as Hg 0 and Hg total ) (shaded Online Hg as Hg Total )

12 Bigger Picture Historical trends in CO & Hg Higher CO With Low NOx burners (as Hg total )

13 Summary of Hg exiting the Fabric Filter Hg affected by burner configuration Similar capture in air and oxy firing modes AIR OXY Low NOx Original Low NOx Original Hg Total gas µg/m * 2 Hg 2+ 0% 77% 65% 87% Hg Total gas µg/m * 0.42 Corrected to 12%CO 2 Hg Captured (by mass balance) 98 % 93% 99% 93% * Highest point in transition corresponding to higher O2

14 SO3 measurements Very low concentrations ppm SO % conversion SO2 ADP in oxy C Most below detection limits Disappointing for researchers Great results for Operators BUT is this the whole story? Sample Description SO3, ppm 1 OXY steady OXY AIR OXY AIR < OXY AIR < AIR steady < AIR OXY < AIR OXY < AIR OXY OXY steady < AIR steady < AIR OXY < AIR OXY < AIR OXY < OXY steady <0.10 Previous Measurements 31/05/2014 OXY steady /06/2014 OXY steady /06/2014 OXY steady 0.58

15 Recall the Gas Cooler on COP flowsheet Gas Cooler used in oxy mode only Bypassed in air mode Potential for cold surfaces during transitions oxy mode Speculation that SO 3 condensing as H 2 SO 4

16 Conclusions The capture of Hg at Fabric Filter >90% Burner configuration has over-riding influence on Hg total In particular Hg 2+ Oxy-firing showed higher concentrations of Hg 2+ Similar to air when corrected to 12% CO2 Expected to be beneficial for downstream capture Combined methods of Total Hg (AC) & Online Hg 0 allowed trends in Hg 2+ to be observed SO3 measurements indicate very low concentrations ppm May be indicator of acid condensation during transitions

17 Thanks for Listening further questions?

18

19 Overview Current work at UoN Experimental Results Key Findings

20 Comparison of SO3 measurements (& estimates)

21 Comparison of Hg measurements (by gas phase mass balancing-has advantage of online)

22 Comparison of Hg measurements (by ash balancing- a poor method for transition tests)

23 Fabric Filter Trial Outcomes SO3 levels below detection limit in transitions SO3 level ppm in steady state oxy-mode Hg affected by burner configuration AIR OXY Low NOx Original Low NOx Original Hg Total gas µg/m * 2 Hg 2+ 0% 77% 65% 87% Hg Total gas µg/m * 0.42 Corrected to 12%CO 2 Hg Captured 98 % 93% 99% 93% * Highest point in transition corresponding to higher O2

24 Oxyfuel research at UoN Part of Callide Oxyfuel Project Feasibility Study Coal reactivity Sulfur impacts Review, SO3 formation, catalytic impacts, ADP NOx in compression Effect of pressure residence time, capture in H2O Laboratory compression system, mass balancing Hg in compression Impact of NOx + P + t Mass balancing Recovery methods Emissions from condensates (depressurised)

25 Further Research Needs Hg-NOx product identification Different sections of compression Higher temperature (<200 C directly after P, dry) After cooling+ water condensation SO2-NOx combined capture in compression Optimised Formation of N2O minimised or accounted for CPU liquid product recovery

26 Research Needs in the COP CPU Australian context Low Coal sulfur, no desox Low Hg + Fabric Filter, no AC guard bed No SCR/nSCR For a Australian retrofit Caustic polishing at low pressure CPU to passively remove NOx + Hg as condensates Cold Box to remove remaining NOx from product CO2 and recycle

27 ANLEC R&D Australian National Low Emission Coal Research & Development Combined Federal Government Funding & Australian Coal Association Addresses: The near term risk reduction and technology developments necessary for successful demonstration of LECT in Australia. The delivery of skills, data and knowledge to assist key stakeholders understand the benefits and deployment risks of LECT's. Support for, and investigation of, issues affecting the performance of the early demonstration projects. Program overall funding across 2012 to 2020 ASK NOEL

28 Publications Stanger, R, T. Ting, L Belo, C Spero, T Wall (2015), Field measurements of NOx and mercury from oxy-fuel compression condensates at the Callide Oxyfuel Project, International Journal of Greenhouse Gas Control 42: , 2015 Stanger, R., T. Ting, C. Spero and T. Wall (2015). Oxyfuel derived CO2 compression experiments with NOx, SOx and mercury removal Experiments involving compression of slip-streams from the Callide Oxyfuel Project (COP). International Journal of Greenhouse Gas Control 41: 50-59, 2015 Stanger R, T Ting, T Wall, High pressure conversion of NOx and Hg and their capture as aqueous condensates in a laboratory piston-compressor simulating oxyfuel CO2 compression, International Journal of Greenhouse Gas Control 29, 2014 Ting T, R Stanger, T Wall, Oxyfuel CO2 compression: The gas phase reaction of elemental mercury and NOx at high pressure and absorption in nitric acid, International Journal of Greenhouse Gas Control, Ting, T., R. Stanger, and T. Wall, Laboratory investigation of high pressure NO oxidation to NO2 and capture with liquid and gaseous water under oxy-fuel CO2 compression conditions. International Journal of Greenhouse Gas Control, 18(0) 2013 ANLECR&D Report website: