Electrical power equivalent

Figure 24.3 Small-scale methanol reformer-evaporator-burner system with 4W electrical power equivalent [44].

A complete methanol fuel processor for the electrical power equivalent range 60-170 W was reported by Holladay et td. [63]. The device, which is shown in Figure 24.7, had a volume of less than 30 cm, a mass lower than 200 g and a... 

Lee et al. [58] from Samsung reported development of a fixed-bed natural gas reformer coupled to a WGS reactor with an electrical power equivalent of 1 kW. The steam reformer was placed in the center of the subsystem, while the annular WGS fixed bed surrounded the reformer separated by an insulation layer. Commercial ruthenium catalyst served for steam reforming, while a copper-based catalyst was used for WGS. A natural gas burner supplied the energy needed by steam reformer. The reformer was operated between 850 and 930 C, while the shift reactor worked between 480 and 530 C. The carbon monoxide content of the reformate was reduced to 0.7 vol.% downstream the shift reactor despite its high operating temperature, because the reformer was operated at high S/C ratio between 3 and 5 the water surplus affected the equilibrium of the WGS reaction positively. At full load, the efficiency of this subsystem was 78% which decreased to 72% at 25% load. 

Docter et al. [61] developed an ATR for gasoline with an electrical power equivalent of 10 kW . It was composed of a mixing zone with fuel, air and water injection, and a metallic monolith of 0.51 volume coated with catalyst. The monolith was heated by electricity at the inlet section and operated at a very high 0/C ratio of 1, which is the stoichiometry of partial oxidation. Steam was added to the feed at S/C ratio of 1.5. These operating conditions resulted a low hydrogen content of about 27 vol.%, which was determined for the reformate. The reactor could be turned down by a ratio of 1 10 within 2 s while operating temperatures decreased from 800° C to about 660° C. The efficiency of the reactor was still in the range of 80% at more than 2 kW power output. 

Lopez et al. [166] described the operation of their mesoscaled folded-plate reactor which was operated with water cooling in a cocurrent flow arrangement, with four stages of air addition (Figure 14.24). Their Au catalyst was operated well below 100°C at an O/CO ratio of 3. The CO could be reduced to values below 100 ppm and the reactor had 0.4-0.6 kW electric power equivalent. 

Membrane separation of reformate is usually operated at elevated pressure, as the driving force for the permeation process. Thus, steam reforming is the preferred procedure, because only liquid pumps are required instead of large compressors for air pressurisation, which draw unacceptable parasitic losses [105], especially for small mobile systems with an electrical power equivalent of less than lOkWei. 

A similar concept study was performed by Seo et al. [449] for natural gas reforming. However, fixed-bed reactors were used and the heat supply originated not from autothermal reforming, but from a catalytic burner in the centre of the fuel processor. Two fuel processors of this type were then built with 1- and 2-kW electrical power equivalents [450]. The smaller system was operated at a S/C ratio 3.0 and 89% methane conversion was achieved, while other hydrocarbons present in the natural gas feed were completely converted. The fuel processor efficiency was calculated as the ratio of the lower heating value of the hydrogen produced to the lower heating value of natural gas fed to the reformer and the burner. It was in the range between... 

Park et ol. [507] increased the size of their methanol steam reformer described above to an electric power equivalent of 28 W and combined steam reforming with catalytic combustion The reactor was sealed by brazing. While the same steam reforming catalyst as described above was coated onto etched channels of200-pm depth and 300-pm width, the catalytic combustor was a small scale fixed-bed of platinum/alumina catalyst spheres... 

Figure 7.23 Energy diagram of a small scale methanol reformer/ evaporator/burner system with 4-W electrical power equivalent [534].

Plasmatron reformers are suitable for the conversion of all types of fuel, including heavy feedstock such as biomass and diesel. Their lower size is limited to an electrical power equivalent of about 1 kWei. 

Electric power (calorific value) Electric power (equivalent value) 3,600 kJ/(kW-h) (860 kcal/(kW-h)) Calculation by current thermal power generation consumed standard coal 0.1229 kgce/(kW-h)... 

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