Compact ammonia storage systems for fuel-efficient NOX emissions reduction

Transcription

1 Compact ammonia storage systems for fuel-efficient NOX emissions reduction Stuttgart, Germany July 5 th to 8 th of July, 2010 Dr. Tue Johannessen Chief Technology Officer Amminex A/S, Denmark tj@amminex.com Ammonia enabling technologies 2010 Amminex A/S 1

2 The environmental paradox: Low CO 2 -but at the expense of NO X? NO 2 is already today a problem in many European cities Focus on CO 2 efficient engines: Efficient diesel engines Exhaust temperature often below 200 C Significant challenge for off-cycle NO X control with AdBlue Improvements in future air quality? Annual mean nitrogen dioxide (ug/m 3 ) in London Limit for Amminex A/S 2

3 NO X reduction potential at continuous low-temperature exhaust NO X conversion data with NH 3 provided by Haldor Topsøe A/S Test conditions: 250 ppmno X Conversion measured with 20 ppmnh 3 slip Space velocity: hr -1. Catalyst: Fe-zeolite; aged for 50hr at 750C NO 2 content: NO 2 /NO X = 0.3 Curve for AdBlue is based on the assumption that: AdBlue gives as high conversion as pure ammonia gas as long as injection is possible (urea hydrolysis complete) Steady-state AdBlue injection requires an exhaust temperature of C (e.g. Dr. Rusch: Urea SCR Interaction of spray generation and exhaust system, CTI Forum: SCR systems, Stuttgart, Oct. 08) NOX conversion relat tive to 200 C Urban NOx control with ammonia gas NH3-dosing: Normalized conversion (NO2/NOx=0.3) AdBlue (inj. at Tscr >190 C) Illustration of urban NO X control potential with liquid injection (AdBlue ) SCR catalyst temperature ( C) 2010 Amminex A/S 3

4 Fundamentally: NO X control by SCR a) Reductant 4NH 3 + 4NO + O 2 4N 2 + 6H 2 O b) Reductant + 2NO + 2NO 2 4N 2 + 6H 2 O 4NH 3 Optimal reductant: Direct ammonia dosing However, liquid anhydrous ammonia is not safe (approx. 8 bar at RT) as on-board storage 2010 Amminex A/S 4

5 Safe but indirect ammonia storage: AdBlue Urea NH 3 + HNCO (T > 160 C) HNCO + H 2 O NH 3 + CO 2 (catalyst; T 200 C) e.g. Dr Oliver Kröcher (CTI-meeting, SCR Systems) Piazzesi et al., Catal. Com., 7, (2006) AdBlue as indirect ammonia storage implicate some challenges: - corrosive liquid; corrosive decomposition products in the exhaust line - uncertainty in the degree of conversion to ammonia urea chemistry - risk of solid deposits (by-products) - freezing issues (thawing strategy, heated lines, ) - undesired urea decomposition in storage tank at T > C - dosing limitation at low exhaust temperature, e.g. urban driving - exhaust design is complicated by need for well-defined spray patterns and mixers - AdBlue quality ( home-made, impurities, etc.) 2010 Amminex A/S 5

6 Core technology of Amminex: Safe ammonia storage controlled release on demand Amminex technology allows ammonia to be chemically stored with volume metric capacity similar to pressurized liquid ammonia. Volumetric ammonia capacity: 2.5 times higher than AdBlue Molecular ammonia storage in AdAmmine is completely reversible Ammonia can be released on-demand by controlled thermal desorption 20 C 80 C 150 C 7 NH 3 1 NH 3 Sr(NH 3 ) 8 Cl 2 Sr(NH 3 )Cl 2 SrCl 2 Material sample: 75 liter NH 3 -gas stored in a block 7 NH 3 (reversible) 1 NH 3 Non-pressurized at room temperature. AdAmmine is not hazardous goods for on-road, sea and air transportation Amminex A/S 6

7 Amminex ASDS technology: Ammonia Storage and Delivery Systems Amminex has developed three system variants: ASDS-1: Electrical system for small/medium cars Two smaller main cartridges pr. system Control strategy for low fuel economy impact ASDS-2/LD: Engine coolant system for medium/large cars Main cartridge size is approx. 9 liters ASDS-2/HD: Engine coolant system for MD/HD Main cartridge(s) is approx. 16 liters Modular system concept 2010 Amminex A/S 7

8 ASDS TECHNOLOGY FOR PASSENGER CARS 2010 Amminex A/S 8

9 Ammonia Storage and Delivery System introduction Cartridge heating by engine coolant ASDS for passenger cars Flow range: g NH 3 /min (6 SLPM) Start-up unit Main AdAmmine cartridge Average power consumption NEDC: 25W Dosing time at from -27 C : 180 sec. Ultra-pure ammonia gas delivered to exhaust line ECU signal Ammonia Flow Manifold (AFM) w. control electronics, flow censor, P-sensor, valve Engine coolant circulation ( 2 liter/min. bypass) Direct ammonia gas dosing SCR Catalyst System parts from automotive suppliers Main cartridge is disconnected and replaced at service - No injector needed; -Steel-tube penetrating the pipe - Simple exhaust geometry & short mixing length - Low pressure drop 2010 Amminex A/S 9

10 Dynamic NH 3 -dosing capability Proportional dosing of ammonia gas SCR reductant is not pulsed High turn-down ratio: 1:100 Flow rate is either zero or [0.01-1] of max. demand Real-time copy of ammonia demand signal from OEM (ECU) After cold start, system is ready for dosing well within catalyst time-to-reach SCR light-off temperature also during freezing conditions. AFM with gas and com. connectors 2010 Amminex A/S 10

11 Controller: ASDS software and OBD Software development in Matlab-Simulink environment Overall system control strategy state machine Control strategy & algorithms for AdAmmine cartridge heating Control of AFM (sensors& dosing valve) OBD functions of ASDS Overall responsibility for NO X control: The OEM OEM is responsible for SCR dosing strategy and overall OBD Link to engine map for engine-out NO X emission Real-time ammonia dosing demand computed by OEM ASDS software can be located as layered object code in the engine control unit (ECU) as layered object code in a dosing control unit (DCU) on separate ASDS controller (e.g. integrated in the Ammonia Flow Manifold) 2010 Amminex A/S 11

12 ASDS TECHNOLOGY FOR MD/HD 2010 Amminex A/S 12

13 ASDS-2/HD for commercial vehicle or truck Max. peak flow of ammonia: 11 g NH 3 /minute. Max. steady state flow: 9 g NH 3 /minute AdAmmine cartridge with 7kg available NH 3. Modular system configuration possible Ammonia Flow Manifold (AFM) Ammonia gas line (to exhaust line interface) Start-up unit (electrical) Engine coolant circulation ( 2-4 liter/min. bypass) Main AdAmmine cartridge 2010 Amminex A/S 13

14 EXAMPLES OF VALIDATION ACTIVITEIS 2010 Amminex A/S 14

15 Status on ASDS validation activities Dynamic dosing according to NH 3 -demand profiles (engine dynoand vehicles) 200,000km combined on-road system tests 10+ passenger cars One complete oil service interval has been demonstrated with an AdAmmine cartridge. Several trucks Fire test of fully saturated cartridge (20 minute duration car fire test) Climate (temperature) Dosing from -27 C cold soak temperature Exposure to hot climate conditions ( Arizona ) Vibration tests focusing on AdAmmine cartridge Still on-going with different OEM specs. Verification of on-board recharging of start-up unit Consistent start-up times during extended stress testing of start-up unit 2010 Amminex A/S 15

16 Cold climate: No issues of freezing/thawing liquid reductant Both LD and MD/HD systems show fast start-up time (time-to-dose) LD application ASDS is ready within the time frame of the SCR catalyst reaching light-off temperature. Minutes HD cold start conditions: -10 C Start-up unit Main 2010 Amminex A/S 16

17 Start-up unit: Endurance test PTC-heated SrCl 2 -STU with ammonia capacity of 82g. Cycles: -startup to 3bar -dosing of NEDC cycle - dosing constant flow(20mg/s) until 50% filling level Re-saturation Unit is weighed to check that capacity is unchanged Results The startup time was very stable over the whole testing period Resaturation up to almost 99% was possible over the whole testing period Post mortem analysis No changes in the salt, as an effect off the endurance test, were observed 2010 Amminex A/S 17

18 Short-distance driving: Start-up unit recharging One OEM has demonstrated positive ammonia mass balance of the start-up unit in a 6km driving cycle from (cold start). Start-up unit was 75% saturated. Room temperature: 10 minute driving 0.6g NH 3 consumedfrom start-up unit and 1.5g NH 3 resaturatedfrom main unit. Low-temperature (-15 C) Engine start, ice-scraping and subsequently 6km driving was performed 2.8 g NH 3 consumedfrom start-up unit and 5g NH 3 resaturatedfrom main unit Amminex A/S 18

19 Integrated flow sensor signal: Cartridge filling level Several experiments of degassing of both passenger car cartridges ( 4kg NH 3 ) and HD systems demonstrated accurate level monitoring based on integrated signal from flow sensor. 1. ASDS-2/LD : 4 kg dosed: 0.3% error 2. ASDS-2/LD : 3.9kg dosed: 1% error 3. ASDS-2/HD system: 17.8kg dosed ( 2.2% error) This accuracy is mainly dependant on the calibration of the sensor Amminex A/S 19

20 NO X REDUCTION PERFORMANCE 2010 Amminex A/S 20

21 ASDS-1:Example of NO X control on OEM vehicle High SCR NO X performance on light vehicle with small diesel engine SCR positioned under-floor Dosing strategy for Amminex system fine-tuned for ammonia gas Options for significant improvement on tailpipe NO X emissions possible compared with AdBlue OEM data: Light vehicle Euro 6 NOx level 2010 Amminex A/S 21

22 ASDS-2/LD: Performance on OEM test vehicle during FTP Coolant temperature for the main cartridge heating (by-pass loop) Start-up unit: Ready to dose after sec. Dosing from main unit takes over. Start-up unit resaturation initiated Low power consumption in the electrically heated start-up unit; watt on average in minute driving cycle Amminex A/S 22

23 ASDS-2/LD:NO X control on OEM test vehicle: NEDC fulfilled NH 3 -dosing initiated at much lower catalyst temperature (early in the NEDC cycle) compared to what is possible with AdBlue No ammonia slip High conversion around SCR temperature of 200 C 2010 Amminex A/S 23

24 ASDS-2/LD:NO X control on OEM test vehicle: FTP75 fulfilled Little or no ammonia slip NH 3 -dosing initiated at low T SCR Almost 100% NOx conversion at C Immediately high conversion in 2 nd part of FTP 2010 Amminex A/S 24

25 ASDS-2/HD: Extending the SCR application range! Flow [mg/s], Temperatu ure [ C], Speed [kmph] emperature ( C) / a dosing NOx conversion / Catalyst te Speed (km/hr) / Ammonia Required catalyst temperature for operating AdBlue: > 200 C Catalyst temperature SCR_avg_T [ C] NOx_conversion [%] Vehicle_speed [kmph] Ammonia_dosed [mg/s] Urban driving pattern for more than one hour with reliable NO X performance. Performance enabled by gaseous ammonia dosing. High NO X conversion possible with continuous cold exhaust temperature using AdAmmine-SCR Time [s] 2010 Amminex A/S 25

26 Solid reductant cartridge for Tier 4? OEM Typically, a large variation in exhaust line configurations challenges the inlet zone of the reductant (injection/spray) Gaseous ammonia inlet zones can be done with no risk of deposits Both straight or bended tubes Potentially move SCR catalyst closer to the heat Shorter mixing zone User/Owner Reductant does not require establishment of liquid handling/storage on e.g. the - sometimes temporary -point of use Amminex A/S 26

27 INDUSTRIALIZATON 2010 Amminex A/S 27

28 AdAmmine processing 2010 Amminex A/S 28

29 First facility for series production First commercial contract landed Amminex has developed production methods for full-scale cartridge production Basic design for full-size plant with two production lines is established Full-scale production trial run to take place in 2011 in a Danish facility 2010 Amminex A/S 29

30 Raw Materials Ammonia Worlds most produced chemical million t/year Extensive production and distribution Anhydrous strontium chloride Occurrence CelestiteSrSO 4, annual production in excess of t/year (StrontianateSrCO 3 ) Mining in Spain, Turkey, China, Mexico Low toxicity: Strontium chloride behaves like calcium chloride with LD 50 ~2000mg/kg body weight Other uses of strontium chloride Additive to toothpaste for sensitive teeth Medical against osteoporosis Intermediate for production of other strontium compounds 2010 Amminex A/S 30

31 Servicing strategy and aftermarket Standard production method: First-fit cartridges on new vehicles Cartridge replacement: Depleted cartridge exchanged with a full unit (e.g. at OEM service station or fleet) Depleted cartridges can be: Resaturated at a decentralized facility (however not directly at OEM dealer or Fleet) Once exhausted, a cartridge can be recycled completely with full utilization of raw materials. The AdAmmine aerosol can For certain applications, the cartridge strategy may be complete recycle because the value of the housing is low compared to the additional efforts of quality assuring a cartridge in a resaturation scenario Amminex A/S 31

32 Aftermarket: AdAmmine cartridges similarities with propane distribution Propane canister (one-time use) 0.5-1kg propane Price in retail: $2.5-3 EUR (Including VAT) Propane transported in bottles: hazardous goods (logistics risk fee ) Solid AdAmmine cartridges: not hazardous goods Propane bottle (refill) 11kg propane Price in retail: EUR 2010 Amminex A/S 32

33 Numerous application examples exist with fast bottle replacement 2010 Amminex A/S 33

34 Illustration of infrastructure and responsibilities High-capacity cartridges allows SCR reductant to be maintained only during serving or via limited infrastructure. AdAmmine cartridges are OEM spare parts; can be distributed via normal dealer/oem infrastructure or networks similar to propane bottles AdAmmine technology allows OEMs to strengthening the the relationship between themselves and the customers No additional burden on driver AdAmmine replacement at certified dealers/workshops with strong links to OEM. Emissions responsibility is moved from the driver to the OEM/Fleet Important for authorities Potential for tampering with emissions reduction system is very low Refill facility First fit/recycle facility (e.g. 1:10 is new ) 2010 Amminex A/S

35 Summary On-board storage of NH 3 is enabled by AdAmmine technology. Approx. 2.5 times lower installed system volume compared with AdBlue. Dynamic and accurate NH 3 dosing. No injector needed at exhaust interface. Reliable SCR performance at low-temperature exhaust during urban driving No limitations due to urea hydrolysis or risk of deposits AdAmmine does not degrade during long-term storage AdAmmine replacement cartridge is an OEM/service spare part Vehicle integration: Clear split of responsibilities First commercial contract landed Fuel-efficient NOx control technology 2010 Amminex A/S 35

36 Thank you for your attention Ammonia enabling technologies 2010 Amminex A/S 36