Kolaczkowski, Stan T

Mcclymont, David

Molloy, Kieran C

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        Citation for published version:Mcclymont, D, Kolaczkowski, ST & Molloy, KC 2010, 'Catalyst system design for the control of NOx usinghydrogen' DTC Summer Showcase 2010, Bath, UK United Kingdom, 8/07/10 - 9/07/10, .Publication date:2010Document VersionPeer reviewed versionLink to publicationUniversity of BathGeneral rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Download date: 13. May. 20196. Experimental Results Catalyst System Design for the Control of NOx Using Hydrogen  David W. J. McClymonta, Stan T. Kolaczkowskib, Kieran C. Molloyc aDoctoral Training Centre bDepartment of Chemical Engineering cDepartment of Chemistry Centre for Sustainable Chemical Technologies, University of Bath, BA2 2AY, UK. E-mail: D.W.J.McClymont@bath.ac.uk: URL: http://www.bath.ac.uk/csct 5. Experimental Conditions • Gas composition supplied to catalysts:  – 1000 ppm NO  – 1000 ppm H2  – Air (12.5 % O2) or N2 • Temperature varied from 50-250 °C (Figure 3)   2. Current De-NOx Processes • NH3/urea-Selective Catalytic Reduction (SCR) is an efficient, established method 4NH3 + 4NO + O2 → 6H2O + 4N2 8NH3 + 6NO2 → 12H2O + 7N2 BUT it requires additional toxic chemicals: – Intrinsic safety issues – Extra system costs – NH3/urea infrastructure necessary     7. Conclusions • In the absence of O2, Pd/Al2O3 catalysts can effectively reduce NOx using H2 • However, Pd/Al2O3 strongly promotes the reaction between H2 and O2, even at low temperatures • Conditioning of the catalyst may be necessary to achieve maximum activity • Some selectivity of products was seen at varying temperatures     3. H2-SCR • H2 is already present in many systems e.g. diesel engines, biomass gasification combined heat and power (CHP) plants • Could replace NH3/urea  processes: Target Chemistry  2NO + 2H2 → 2H2O + N2 2NO2 + 4H2 → 4H2O + N2 • Removes the need for additional chemicals and their associated costs 4. Catalyst • Pd/Al2O3 catalyst prepared using an incipient wetness impregnation technique • Supported on honeycomb monoliths (Figure 1) – Outer diameter = 14 mm – Channel size = 1 mm x 1 mm (x 80) • Compared to commercially available 1 wt% Pd/Al2O3 pellets (Figure 2)  – Diameter = 3 mm Figure 1 – Pd/Al2O3 monoliths  Figure 2 – 1 wt% Pd/Al2O3 pellets  1. What is NOx? • Nitric Oxides - highly reactive gases; primarily NO (>90 %) and NO2 • Pollutants, involved in many atmospheric processes e.g. formation of smog • Produced as a result of the high temperatures during combustion of fossil fuels • Legislation is in place to reduce NOx emissions                            14mm 10mm 02004006008001000120014001600100 200 300ppm of species in outlet stream Temperature (°C) Monolith in Presence of O2 NOH2Delivered Concentration 02004006008001000120014001600100 200ppm of species in outlet stream Temperature (°C) Pellets in Presence of O2 NOH2Delivered Concentration 0200400600800100050 150ppm of species in outlet stream Temperature (°C) Monolith in Absence of O2 NOH2Delivered Concentration 0200400600800100050 150ppm of species in outlet stream Temperature (°C) Pellets in Absence of O2 NOH2Delivered Concentration Figure 3 – Experimental set-up  Thermocouples Analysis 4000 ppm NO/N2 8000 ppm H2/N2 Air or N2 Electric Furnace Two way valve Reactors Thermocouples 

Catalyst system design for the control of NOx using hydrogen

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Catalyst system design for the control of NOx using hydrogen

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