10 20 n

Figure 3.1 Heats of combustion of hydrocarbons and alcohols.

An alcohol results when an OH radical replaces a hydrogen in a hydrocarbon (Figure 3.2). Gaseous hydrocarbons form liquid alcohols. Thus, for vehicles (where a liquid is more useful than a gas), it is advantageous to partially oxidize hydrocarbons, transforming them into alcohols. This partial oxidation causes the alcohol to have a smaller heat of combustion than the parent hydrocarbon:

CH4 (55.6MJ/kg) yields CH3OH (22.7MJ/kg), C2H6 (52.0MJ/kg) yields C2H5OH (29.7MJ/kg).

However, 1 kmole (16 kg) of methane yields lkmole (32 kg) of methanol. Hence, 1 kg of methane can be transformed into 2 kg of methanol with an efficiency of

Table 3.2 Higher Heats of Combustion of Hydrocarbons of the

Form C„H2„+a


a ^ 2

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Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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