Reformate methanol-based

Fig. 1. Fquilihrium conversion of carbon oxides to methanol based on reformed natural gas composition of 73% H2, 15% CO, 9% CO2, and 3% CH ...

A fourth area for research opportunities is in the development of fuel cells. There is a need to develop electrode materials for methanol-based fuel cells. This would allow for the use of liquid fuel directly without a reformer. Less expensive alternatives to Nafion are required for fuel cell membranes. Rapid-response onboard reformers are also needed for potential use in conjunction with the fuel cell to convert liquid fuel to hydrogen. 

A block diagram of the FP integrated with FC is presented in Figure 15.i. in this system the fuel is methanol, which is stored in a storage tank as an aqueous solution. Excess water in the feed is needed to reduce CO formation in the reformer and avoid dehydration of the FC. Methanol is evaporated in the vaporizer as all reactions in the FP-FC system take place in the gas phase. In the reformer methanol is converted into a hydrogen-rich gas at 250 °C over a Cu-based catalyst according to the endothermic steam reforming reaction. 

Lyubovsky and Roychoudhury reported the development of an autothermal reformer for methanol based upon the Microlith technology of Precision Combustion Inc. [190]. Two types of reactors were tested. The first reactor consisted of cylindrical metallic gauzes of 41-mm diameter, wash-coated with a precious metal catalyst and piled up to a total height of 6 mm. The reactor thus had a low volume of 8 cm and was operated at very high fiow rates (gas hourly space velocity up to 400 000 h ), which corresponded to a residence time of 3.5 ms [190]. The O/C ratio was varied from 0.05 to 0.58 and the S/C ratio between 0 and 2. Figure 7.2 shows the... 

In any case, one of the most important issues to be prevented in SOFC systems is carbon deposition (coke formation) from the fuels. Figure 6.21 shows the equilibrium products for (a) methane- and (b) methanol-based fuels with the steam-to-carbon (S/C) ratio of 1.5 at elevated temperatures [251]. Assuming thermochemical equilibrium, carbon deposition is not expected to occur within a wide temperature range. The calculated results for various other fuels mentioned above have been shown elsewhere [251]. The minimum amounts of H2O (water vapor) necessary to prevent carbon deposition are shown in Fig. 6.22 for hydrocarbon fuels. While S/C of 1.5 is enough for CH4, higher S/C is needed with increasing carbon number of hydrocarbons, especially at lower temperatures. Such dependencies have also been revealed for O2 (partial oxidation) and CO2 (CO2 reforming) [251] to prevent carbon deposition. 

Thermodynamic calculations show that at a H2 C02 ratio of 3 1, which is representative for a methanol-based reformate, CO produced by the RWGS, which is proceeded in the fuel cell itself, could be in e range of 20 to 50 ppm... 

Araya SS, Andreasen SJ, Kaer SK (2012) Experimental characterization of the poisoning effects of methanol-based reformate impurities on a PBI-based high temperature PEM fuel cell. Energies 5 4251 267... 

In addition, some fuel cells will require deep-desulfiuized fuels. For example, methanol-based fuels for on-board fuel cell applications require the use of a fuel with sulfur content <1 ppmw in order to avoid poisoning and deactivation of the reformer catalyst. To use gasoline or diesel commercial fuels, which are the ideal fuels for fuel cells because of their high energy density, ready... 

In this section, we consider two different applications (i) a methanol-based reformer and fuel cell system, and (ii) an ammonia-based reactor and fuel cell system. Design issues for both systems are considered for generating 100 W of power. 

Considering a plant designed to produce 2500 tpd methanol based on the aforementioned feed the following feed and fuel requirements are estimated for a plant utilizing 10 MPa synthesis and steam reforming for syn neration [18] ... 

MPa (300—400 psig), using a Ni-based catalyst. Temperatures up to 1000°C and pressures up to 3.79 MPa (550 psia) are used in an autothermal-type reformer, or secondary reformer, when the hydrogen is used for ammonia, or in some cases methanol, production. 

High temperature steam reforming of natural gas accounts for 97% of the hydrogen used for ammonia synthesis in the United States. Hydrogen requirement for ammonia synthesis is about 336 m /t of ammonia produced for a typical 1000 t/d ammonia plant. The near-term demand for ammonia remains stagnant. Methanol production requires 560 m of hydrogen for each ton produced, based on a 2500-t/d methanol plant. Methanol demand is expected to increase in response to an increased use of the fuel—oxygenate methyl /-butyl ether (MTBE). 

Steam Reformings of Natural Gas. This route accounts for at least 80% of the world s methanol capacity. A steam reformer is essentially a process furnace in which the endothermic heat of reaction is provided by firing across tubes filled with a nickel-based catalyst through which the reactants flow. Several mechanical variants are available (see Ammonia). 

Based on these developments, the foreseeable future sources of ammonia synthesis gas are expected to be mainly from steam reforming of natural gas, supplemented by associated gas from oil production, and hydrogen rich off-gases (especially from methanol plants). 

Natural gas and crude oils are the main sources for hydrocarbon intermediates or secondary raw materials for the production of petrochemicals. From natural gas, ethane and LPG are recovered for use as intermediates in the production of olefins and diolefms. Important chemicals such as methanol and ammonia are also based on methane via synthesis gas. On the other hand, refinery gases from different crude oil processing schemes are important sources for olefins and LPG. Crude oil distillates and residues are precursors for olefins and aromatics via cracking and reforming processes. This chapter reviews the properties of the different hydrocarbon intermediates—paraffins, olefins, diolefms, and aromatics. Petroleum fractions and residues as mixtures of different hydrocarbon classes and hydrocarbon derivatives are discussed separately at the end of the chapter. 

In this study, we developed microchannel PrOx reactor to control CO outlet concentrations less than 10 ppm from methanol steam reformer for PEMFC applications. The reactor was developed based on our previous studies on methanol steam reformer [5] and the basic technologies on microchaimel reactor including design of microchaimel plate, fabrication process and catalyst coating method were applied to the present PrOx reactor. The fabricated PrOx reactor was tested and evaluated on its CO removal performance. 

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