Session 41 Mathias Magnusson

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Transportforum 2012, January 11-12th

Linköping

NOx Abatement Technique for Marine

Applications

Improved SCR Systems

Mathias Magnusson

PhD Student Department of Shipping and Marine Technology

Sustainable Ship Propulsion

mathias.magnusson@chalmers.se

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Outline

• Background

• Paper I:The influence of sulfur dioxide and water on the performance of

a marine SCR catalyst - Method

- Results and Concluding Remarks

• Paper II: A system perspective on practical experiences of marine SCR

installations - Method

- Results and Concluding Remarks

• Final concluding remarks and Outlook

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Background

• Environmental implications of NOx? - Eutrophication

- Acidification

- Contribution to ground level ozone

- Contribution to secondary particulate matter (PM)

• NOx emissions from shipping? - Global level: suggested that approx. 15% of all global anthropogenic NOx emissions

originates from vessels, with approx. 70% occurring within 400 km of land.

- European level: NOx emission from international shipping (EU) is projected to increase by

67% between 2000 and 2020 exceeding the total of all land-based sources in EU-25 in

2020.

- Regional level: NOx emission from vessels in the Baltic Sea during 2007 ~ 122 ktones of

nitrogen Sweden ~ 50 ktones of nitrogen.

- Swedish level: In addition, EMEP 2011 suggests 20% by shipping

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Background

• Incentives and regulations for reduced NOx emission from shipping?

- The Norwegian NOx fund and the Swedish environmentally differentiated fairway dues

- IMO’s Revised MARPOL Annex VI – Reg. 13

Demand for NOx abatement technology!

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Background

• NOx abatement technologies - Primary (combustion); IEM, EGR, Water techniques, LNG…

- Secondary (after-treatment); SCR

• Selective Catalytic Reduction (SCR)

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Method Paper I

• The aim: investigate how sulfur, water and low temperatures affect an SCR

- experimental flow reactor studies

- commercial vanadia-based washcoated urea-SCR catalyst for marine applications

𝑆𝑉 =𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝑔𝑎𝑠 𝑓𝑙𝑜𝑤

𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑡𝑕𝑒 𝑐𝑎𝑡𝑎𝑙𝑦𝑠𝑡

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Flow reactor studies on SCR-activity as a function of

SO2-concentration

Feed gas composition:

500 ppm NO, 500 ppm

NH3, 8% O2 and 100-

1100 ppm SO2 (350oC

and 12200 h-1)

200 ppm SO2 ≈ 1 wt.% S

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Flow reactor studies on SCR-activity as a function of

temperature (SO2 + H

2O)

Feed gas composition:

500 ppm NO, 500 ppm

NH3, 8 % O2, 500 ppm

SO2 and 4 % H2O (SV

6100 h-1 or 300oC)

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Concluding Remarks Paper I

• In general, the addition of SO2, in the absence of water, promotes NOx

reduction and NH3 conversion along with increased formation of N2O

Formation of new acid sites that improve NH3 adsorption?

• In general, the addition of water, in the absence of SO2, decrease NOx

reduction and NH3 conversion along with reduced formation of N2O

Competitive adsorption on vanadia sites and reduced NH3 oxidation?

• In general, in the presence of both SO2 and water, the activity for NOx

reduction decreases at high concentrations of SO2 (>500 ppm) low

temperatures (< 300oC) and high space velocities (> 12200 h-1)

Complementary studies suggest formation of ammonium sulfates?

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Method Paper II

• The aim: identify important technical, human and organizational conditions

necessary for safe, efficient and sustainable operations of SCR

- Combination of focus group interviews (n=6+2) and individual interviews (n=5)

- Theme:

1) Installation; newbuilding and retrofit, decision making, stakeholder communication

2) Operation, service and maintenance; usability, accessibility, manuals, support, outage

3) Knowledge and training; before and after installation, knowledge transfer

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Practical experiences of marine SCR

installation

• Installation - Corporate environmental image and commercial benefits

- Price is the prime consideration, and flexibility and adaptability second

• Operation, service and maintenance - Urea quality and logistics

- Technical design issues: operating temperature, the space requirements & dimensions, urea

injection, high gas velocities and insufficient mixing of urea and exhaust gases

- Risks to the crew and/or service personnel

- No claims regarding SCR – the owners carry the cost

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Practical experiences of marine SCR

installation

• Knowledge and training - SCR is complex, chemical reactions not well understood

- SCR did not require any special training or knowledge, but some had arranged extra training

for their crew. (Note: hundreds of systems and the SCR is not a safety-critical system!)

- SCR suppliers are interested in improved training

- Cargo owners supposed sufficient training – safe and efficient operation

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Concluding Remarks Paper II

• Clear and concise incentives are needed

Regulations, customer demands or other commercial benefits?

• Design and operational challenges

Supply and quality of urea, urea-injection, exhaust gas

composition due to various marine fuel and lubrication oils?

• Lack of structure for training, development and transfer of knowledge of

SCR (chemical and practical)

Increased risk for occupational accidents and unnecessary

harmful emissions to the environment? (Cost x 3)

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Final Concluding Remarks and Outlook

• SCR is a highly efficient NOx abatement technology, but…

- …certain risks of deactivation, but may be avoided…(exhaust gas temperature, space

velocity and sulfur concentrations)

- …high overall efficiency requires appropriate and sufficient knowledge of how the system

works and what the prerequisites are to achieve successful SCR operation

• Outlook

- Flow reactor experiments using different types of urea?

- Flow reactor experiments with varying diesel exhaust gas compositions?

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Thank you for the attention!

Mathias Magnusson PhD Student

Shipping and Marine Technology

Sustainable Ship Propulsion

Chalmers University of Technology

Phone: +46(0)31-772 36 15

Mobile: +46(0)72-194 87 88

E-mail: mathias.magnusson@chalmers.se

Web: www.chalmers.se/smt