An Innovative Injection and Mixing System for Diesel Fuel Reforming
This project focused on fuel stream preparation improvements prior to injection into a solid oxide fuel cell reformer. Each milestone and the results from each milestone are discussed in detail in this report. The first two milestones were the creation of a coking formation test rig and various testing performed on this rig. Initial tests indicated that three anti-carbon coatings showed improvement over an uncoated (bare metal) baseline. However, in follow-up 70 hour tests of the down selected coatings, Scanning Electron Microscope (SEM) analysis revealed that no carbon was generated on the test specimens. These follow-up tests were intended to enable a down selection to a single best anti-carbon coating. Without the formation of carbon it was impossible to draw conclusions as to which anti-carbon coating showed the best performance. The final 70 hour tests did show that AMCX AMC26 demonstrated the lowest discoloration of the metal out of the three down selected anti-carbon coatings. This discoloration did not relate to carbon but could be a useful result when carbon growth rate is not the only concern. Unplanned variations in the series of tests must be considered and may have altered the results. Reliable conclusions could only be drawn from consistent, repeatable testing beyond the allotted time and funding for this project. Milestones 3 and 4 focused on the creation of a preheating pressure atomizer and mixing chamber. A design of experiment test helped identify a configuration of the preheating injector, Build 1, which showed a very uniform fuel spray flow field. This injector was improved upon by the creation of a Build 2 injector. Build 2 of the preheating injector demonstrated promising SMD results with only 22psi fuel pressure and 0.7 in H2O of Air. It was apparent from testing and CFD that this Build 2 has flow field recirculation zones. These recirculation zones may suggest that this Build 2 atomizer and mixer would require steam injection to reduce the auto ignition potential. It is also important to note that to achieve uniform mixing within a short distance, some recirculation is necessary. Milestone 5 generated CFD and FEA results that could be used to optimize the preheating injector. CFD results confirmed the recirculation zones seen in test data and confirmed that the flow field would not change when attached to a reformer. The FEA predicted fuel wetted wall temperatures which led to several suggested improvements that could possibly improve nozzle efficiency. Milestone 6 (originally an optional task) took a different approach than the preheating pressure atomizer. It focused on creation and optimization of a piezoelectric injector which could perform at extremely low fuel pressures. The piezoelectric atomizer showed acceptable SMD results with fuel pressure less than 1.0 psig and air pressure less than 1.0 in H2O. These SMD values were enhanced when a few components were changed, and it is expected would improve further still at elevated air temperatures. It was demonstrated that the piezoelectric injector could accomplish the desired task. The addition of phase tracking and a burst mode to the frequency controller increased the usability of the piezoelectric injector. This injector is ready to move on to the next phase of development. Engine Components has met the required program milestones of this project. Some of the Milestones were adjusted to allow Milestone 6 to be completed in parallel with the other Milestones. Because of this, Task 3.10 and 3.13 were made optional instead of Milestone 6. Engine Components was extremely grateful for the support that was provided by NETL in support of this work.
- Research Organization:
- Delavan Incorporated
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FC26-04NT42229
- OSTI ID:
- 936087
- Country of Publication:
- United States
- Language:
- English
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