Fuel autothermal diesel

Karatzas, X, Nilsson, M, Dawody, J, Lindstrom, B, Petterson, LJ. Characterization and optimization of an autothermal diesel and jet fuel reformer for 5 kWe mobile fuel cell applications. Chem. Eng. J. 2010 156 366-379. 

The main individual reactions that take place in the reformer (e.g., reactions (1), (2) and (5)) will be considered separately from the overall autothermal reaction for two reasons. First, in ATR the reactor can be considered as two plug-flow reactors in series (1) a very fast POX reaction occurs at the top of the catalyst bed and utilizes a small portion of the bed and (2) a slow SR utilizes the remainder of the reactor bed. Therefore, an optimal ATR catalyst must have excellent SR eatalytic properties. Second, there may be situations in which liquid fuels are reformed using only these individual reactions e.g., diesel fuel may be reformed using only SR (reaction (2)) or only by POX (reaction (1)). 

Table 6) indicate that the fuel-processing efficiencies decrease in the order of steam reforming > autothermal reforming > partial oxidation for both gasoline and diesel fuels. 

Autothermal reformers and CPO are being developed by a number of groups, mostly for fuel processors of gasoline, diesel, and JP-8 fuels and for natural gas-fueled proton exchange membrane fuel cell (PEMFC) cogeneration systems. A few examples are the following ... 

Kinetic Measurements Preliminary studies have been conducted for the kinetic model development for the autothermal reforming of diesel fuel. Three... 

Kinetic modeling of diesel autothermal reforming is extremely complicated. Diesel fuel consists of a complex variable mixture of hundreds of hydrocarbon compounds containing paraffins, isoparaffins, naphthenes, aromatics, and olefins. To simplify the model, a steady-state power law rate expression for the diesel reforming over each type of catalyst used in this study was developed. A linearized least-squares method of data analysis was used to determine the power law parameters from a series of diesel ATR experiments. The power law rate model for diesel autothermal reaction may be written as ... 

Kaila RK, Krause AOI (2006) Autothermal refraining of simulated gasoline and diesel fuels. 

Cheekatamarla PK, Lane AM (2005) Catalytic autothermal reforming of diesel fuel for hydrogen generation in fuel cells I. Activity tests and sulfur poisoning. J Power Sources 152 256-263... 

Simulation work performed by CutUlo et al. for diesel fuel processing [34] revealed that steam reforming has a higher system efficiency than autothermal reforming when the anode off-gas is utilized. 

The fuel injection turns out to be a critical issue for autothermal reforming of heavy hydrocarbon fuels such as diesel and kerosene. In particular the contact of air with the fuel at elevated... 

Karatzas et al. [34] performed autothermal reforming of tet-radecane, low sulfur, and Fischer-Tropsch diesel in a monolithic reformer over rhodium/ceria/lanthana catalyst. The reformer had a thermal power output of 14 kW. It was composed of an inert zirconia-coated alumina foam for feed distribution at the reactor inlet and two 400 cpsi cordierite monoliths coated with the catalyst switched in series. At an O/C ratio of 0.45, a S/C ratio of 2.5 and temperatures exceeding 740°C, full conversion of the low sulfur feed was achieved, while the formation of the byproduct ethylene was between 100 and 200 ppm. As shown in Figure 14.7, an increasing S/C ratio suppresses ethylene formation. The catalyst showed stable performance for 40 h duration. Karatzas et al. [44] determined experimentally as shown in Figure 14.8 that the efficiency of their ATR increased with increasing fuel inlet temperature and O/C ratio. 

Kang, I, Bae, J, Yoon. S. Yoo, Y. Performance improvement of diesel autothermal reformer by applying ultrasonic injector for effective fuel delivery. J. Power Sources 2007 172 845-852. 

Diesel and industrial gas oils may be evaporated in the cool flame unit under conditions of partial oxidation or autothermal reforming [69]. The evaporated feed may then serve as feed for homogeneous or catalytic reforming downstream of the cool flame unit. The cool flame area requires a flame arrester for separation from the reformer. The temperature ofthe cool flame of course increases with increasing air/ fuel ratio. Addition of inert gas decreases the temperature of the cool flame r is the mass ratio of inert gas flow to the air flow ... 

Cheekatamarla and Lane [8] observed a temperature rise from 400 °C to less than 800 °C in an adiabatic testing reactor for autothermal reforming of diesel fuel. 

Cheekatamarla and Lane ]257] found higher hydrogen yield and a lower content of light hydrocarbons for autothermal reforming of synthetic diesel fuel over bimetallic platinum/palladium and platinum/nickel catalysts compared with the monometallic samples. The catalysts showed medium-term stability for 50-h test duration in the presence of sulfur in the feed ]258]. 

Cheekatamarla and Lane [268] observed 50% loss of specific surface area for their 1 wt.% platinum/ceria catalyst after 56 h of autothermal reforming of synthetic low sulfur (10 ppm) diesel fuel. In parallel, the dispersion of the platinum decreased from 51 to 41%. These workers did not attribute a sintering process of the platinum to the latter effect. However, platinum in particular is known to suffer from dispersion losses when exposed to an oxidising atmosphere even at temperatures exceeding not more than400 °C [269]. Thus, both the carrier material and the active species suffered from the elevated temperature of the reforming process. 

A higher tolerance to sulfur poisoning was observed for autothermal reforming of synthetic diesel fuel over bimetallic platinum/palladium and platinum/nickel catalysts compared with monometallic samples [257]. 

Figure 5.52 Schematic of the process of a diesel fuel processor based on autothermal reforming, as designed by Cutillo et al. [443],...

Two 50-kW fuel processors concepts were compared by Lattner and Harold [405]. Both systems had autothermal reformers combined with either catalytic carbon monoxide dean-up or membrane reactor configurations. Tetradecane was used as the model substance for diesel fuel. 

Figure S.SS Configuration of a diesel fuel processor based upon an autothermal membrane reformer reactor [405].

Aicher et al. [72] developed an autothermal reformer for diesel fuel dedicated to supplying a molten carbonate fuel cell system from Ansaldo Fuel Cells S.p.A., Italy. The diesel fuel (which contained less than 10 ppm sulfur for the pilot plant application) was injected into the steam and air flows, which were pre-heated by a diesel burner to 3 50 °C. The reactor itself was operated at 4 bar, a S/C ratio of 1.5 and high O/C ratio of 0.98, which makes the reactor into a steam supported partial oxidation device. Consequently, the dry hydrogen content of the reformate was rather low with less than 35 vol.%. The operating temperature of the honeycomb had to be kept well above 800 °C to prevent coke formation and the presence of light hydrocarbons such as ethylene and propylene in the reformate. The reactor was operated for 300 h, which led to a slight deterioration in the catalyst performance. 

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