Wuyin Wang, Olaf Stallmann

2015-10-29

NOx Control in Oxy-firing Process

Wuhan

© ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

NOx Control in Oxy-firing Process - 04/11/2015 – P 2

Overview of NOx in Oxy

NOx in

Combustion

CO2 compression

© ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Overview of NOx in Oxy

Oxy - vs. Air - firing

• NOx formation−Oxy combustion:

• NOx is reduced due to recycle of the gas • Less NOx, ~30% (on mass basis)*

−GPU: NO oxidation is greatly enhanced under pressure.

• NOx is related to −Emissions −CO2 product quality−Acid formation and operation issues in GPU

* Callide, Spero 2013

© ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

NOx Control in Oxy-firing Process - 04/11/2015 – P 4

NOx Control for Oxyfuel

Pilot Experience Overview (Excerpt)

• Conventional SCR (Schwarze Pumpe, Ciuden)

• LiconoxTM (Schwarze Pumpe)−Alkali and ammonia wash−Fertilizer as by-product

• Sour Compression (Schwarze Pumpe)−Scrubbing at 10-15 bar for SOx, NOx, Hg−NOx scrubbing at 30 bar

• CryocapTM (Callide, Ciuden)− LP scrubber for SOx, NOx, HCl, HF (~atmospheric)−HP scrubber

© ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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SCR in the GPU

Alstom’s Pressurized SCR

• Advantages−High efficiency, controlled reduction of NOx

−Benefits from clean gas: low SOx, low dust and thus less deactivation

−High pressure: less catalyst amount−NOx to N2

4NO + 4NH3 + O2 → 4N2 + 6H2O

NO + NO2 + 2NH3 → 2N2 + 3H2O

SCR

© ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

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Alstom’s Oxyfuel Development

GPU Pilot• 0,3 MWth

• 4 stage reciprocating compressor • Synthetic flue gas or connect to a slip stream• Movable set-up• Fully automated system with extensive measurement and monitoring

© ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

NOx Control in Oxy-firing Process - 04/11/2015 – P 7

GPU Pilot Test

NOx control by SCR in GPU results• Validated with flue gas from Alstom’s 15 MW BSF Pilot

• Extensive technology development at Alstom’s technical center to achieve

− High performance− Low NH3 slip− System integration− No solid formation − Less deactivation

© ALSTOM 2015. All rights reserved. Information contained in this document is indicative only. No representation or warranty is given or should be relied on that it is complete or correct or will apply to any particular project. This will depend on the technical and commercial circumstances. It is provided without liability and is subject to change without notice. Reproduction, use or disclosure to third parties, without express written authority, is strictly prohibited.

NOx Control in Oxy-firing Process - 04/11/2015 – P 8

Summary

NOx Control by Pressurized SCR• Successful test campaigns were conducted where NOx was reduced

by over 95%.

• This solution may allow to omit the conventional SCR for Oxy-firing plants -> R&D effort is continued

• Economic advantages− High efficiency− Less amount of catalyst− Enhanced lifetime of the catalyst− Reliable operation

• Produce environmentally neutral N2− No wastes generated

• Use widely accepted chemicals as reagent.

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