Energy, fuel types methanol

Figure 4.8 A car that uses methanol in its fuel system. Methanol is a very versatile substance. In this van methanol is converted to hydrogen, which is then combined with oxygen in a fuel cell, a type of battery. The fuel cell generates electric energy that runs the car. (Ballard Power Systems, Inc.)...

Fuel cells can continuously convert the chemical energy of a fuel (hydrogen, methanol, methane, etc.) and an oxidant into electrical energy at up to 70% efficiency with very low pollutant emissions. Depending on the type of electrolyte used in a fuel cell, one can distinguish five main types ... 

Fuel cells are usually open systems, and their energy density and specific energy is largely based on the storage of fuel (and oxidant in the case of air-independent systems). Of the fuel cell types considered here, hydrogen PEMs, PAFCs and hydrogen AFCs use hydrogen as fuel, direct methanol fuel cells (DMFC) use aqueous methanol solution or pure methanol, and (alkaline) direct borohydride fuel cells (DBFC) use sodium borohydride solution as the liquid fuel. 

The DMFC is the most attractive type of fuel cell as a powerplant for electric vehicles and as a portable power source, because methanol is a liquid fuel with values for the specific energy and energy density being about equal to half those for liquid hydrocarbon fuels (gasoline and diesel fuel). 

One possibility for supplying household energy is to distribute electricity from central fuel cell-based power plants to houses in the surrounding area. However, it may become cheaper to store methanol in each plant and use it in the co-generation of heat and electricity.19 Such a scheme would also make possible advantages in the distribution of lighting in households via pipes from a central light source powered by fuel cells. This type of situation may provide an application for phosphoric acid cells. 

As fuel for fuel cells are used commonly hydrogen, methane, methanol, metal hydrides and other substances. Hydrogen has the highest weight specific energy (32,702 W-h/kg). The main types of hydrogen fuel cells are following ... 

In recent decades, research has intensified to develop commercially viable fuel cells as a cleaner, more efficient source of energy, due to the global shortage of fossil fuels. The challenge is to achieve a cell lifetime suitable for transportation and stationary applications. Among the possible fuel cell types, it is generally believed that PEM fuel cells hold the most promise for these uses [10, 11], In order to improve fuel cell performance and lifetime, a suitable technique is needed to examine PEM fuel cell operation. EIS has also proven to be a powerful technique for studying the fundamental components and processes in fuel cells [12], and is now widely applied to the study of PEM fuel cells as well as direct methanol fuel cells (DMFCs), solid oxide fuel cell (SOFCs), and molten carbonate fuel cells (MCFCs). 

Interest in methanol as an alternative fuel revived in the late 1990s—for fuel cells. It wasn t the first time this type of alcohol attracted the attention of the clean-energy community. A number of strategists had argued decades earlier that hydrogen, normally a gas, might not be the preferred eco-fuel for automotive use after all and that perhaps some other liquid fuel might be preferable. 

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