INGAS 6th Month meeting, Prague, May 2009 Institut für Chemische Verfahrenstechnik D Stuttgart, Böblingerstr. 72 6th month meeting Prague, May 2009 WP B2.3: Exhaust heating/Catalyst concepts Institute for Chemical Process Engineering of Stuttgart University, Germany -USTUTT-

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 2 Stationary simulation results for methane combustion in heat exchanger reactor –Folded metal sheet –Ceramic monolith Preliminary cold start simulation results for folded metal sheet reactor Cold start burner: lab experiments for catalytic partial oxidation of methane –Description of experimental setup –Preliminary equilibrium computations –Experimental data Outline

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 3 Simulated system Object-oriented structure allows to set up functional modules Connection with GUI-based tool ProMot Code generation, compilation and simulation in DIANA –Basic steps:

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 4 Basic system properties (folded sheet) Geometric parameters Overall length L[m]0.25 Coated length L c [m] 0.1 Cell density[cpsi]385 Overall width W[m]0.1 Channel height H[mm]1.5 Wall thickness D w [µm]110 Spacer thickness D s [µm]50 Number of channels160 L LcLc W H DwDw DsDs Dimensions: 100x240x250 mm

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 5 Basic system properties (folded sheet) Physical properties of metallic heat exchanger Heat conductivity steel s [W/m/s]22 Density steel  s [kg/m 3 ] 7800 Heat capacity steel c p s [kJ/kg/K]0.58 Total mass flow[kg/h] Methane concentration[ppm]2000 Oxygen concentration ( =1), N 2 to balance [ppm]4000 Adiabatic temperature full conversion [K]53 Simulation parameters

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 6 Stationary results Inflow temperature: 350 °C Total flow rate: 50 kg/h Power law approach for methane combustion rate: r CH4 =kp CH4

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 7 Stationary results Inflow temperature: 350 °C Total flow rate: 100 kg/h

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 8 Stationary results Inflow temperature: 350 °C Total flow rate: 200 kg/h

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 9 Amplification factor Axial heat conduction / Heat losses Heat transfer limitation

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 5 % 10 Amplification factor vs. coated length Slope: –Influence of axial heat conduction Extinction 50 % 95 % 5 % 50 % 95 %

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 11 Basic system properties (ceramic)  D w =0.17 mm for all cell densities  Results comparable to folded metal case Cell density [cpsi] Hydraulic Diameter [mm] dhdh Mass transfer at every channel wall Heat transfer at top and bottom wall only (worst case estimation)

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain Amplification factor Extinction Axial heat conduction Peaks: –Axial heat conduc- tion for higher  wall Results comparable to folded metal sheet hex

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 13 Cold start tests; Modifications Controller T_out_inflow Proportional control for bypass ratio Switching between top- and bottom-feed possible, constant exhaust flow (40 kg/h) Constant burner flow (10 kg/h, constant T (1000 °C)) –Gas concentrations based on stoich. combustion of methane

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain t t 14 Cold start tests; Flap system 200 to st. state: Feed at bottom burner off tt Steady state 0 to 60s: Feed at top burner on 70 to 190s: Feed at bottom burner on

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 15 Cold start tests; No flap 0 to 200s: Feed at bottom burner on 210 to st. state: Feed at bottom burner off t t Steady state

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 16 Cold start tests; Bypass ratios; CH 4 emissions Case 1: Total CH 4 emissions from 0 to 250s: 1251 mg Case 2: Total CH 4 emissions from 0 to 250s: 1406 mg  Flap system is beneficial  Higher burner rates necessary  Bypass causes high CH 4 emissions THC Requirements for ECE15+EUDC (EU5): 75mg/km x 11 km = 825 mg

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 17 Conclusions/Outlook simulations Conclusions: –Simulation environment for stationary and dynamic computations developed –Stationary and dynamic computations performed –Efficient cold start strategy is still subject of discussion –Flap system implemented allowing to start with hot gas at the catalytic zone –High burner rates necessary to attain full conversion as quickly as possible Outlook: –Dynamic simulation with NEDC-data obtained from DAIMLER –Dimensioning of heat exchanger based on these results –Input of CH 4 light-off data from experiments with CNG-catalyst from ECOCAT –Definition of boundary conditions for burner system

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 18 Cold start burner Main tasks of burner: –Rapid start-up procedure, total oxidation of methane ( >= 1) –Low secondary emissions –Partial oxidation during operation of vehicle: –syngas for combustion on main catalyst or as reducing agent ( < 1) Total input [kg/h] (CH 4 +Air), =1 Output [kW] Theoretical output (no heat loss):

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 19 Partial oxidation of methane Equilibrium flash calculations (Multiflash, Infochem)

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 20 Experimental setup T1T1 T2T2 T3T3 CO, CO 2, O 2, THC

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 21 Partial oxidation experiments Results for state of the art three way catalyst:

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 22 Partial oxidation experiments Results for diesel-POX catalyst:

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 23 Conclusions/Outlook burner Conclusions: –Diesel POC shows slightly higher selectivities towards H 2 /CO –POX works for different O/C ratios and for high space velocities –Heat losses might be a problem Further development of burner: –Attachment of burning chamber for homogeneous combustion –Development of cold-start strategy (input from NEDC-simulations) –Test of different operating conditions

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 24 Appendix

INGAS 6th Month meeting, Prague, May 2009 INGAS INtegrated GAS Powertrain 25 Basic system properties (ceramic) Physical properties of ceramic heat exchanger Heat conductivity cordierite c [W/m/s]2 Density cordierite  c [kg/m 3 ] 1632 Heat capacity cordierite c p c [kJ/kg/K]0.58 Total mass flow[kg/h] Methane concentration[ppm]2000 Oxygen concentration[ppm]4000 Adiabatic temperature full conversion [K]53 Simulation parameters