Lecture 13 - tau.ac.il

Lecture 13Alternative energy sources

Biodiesel from plant oils and from Aglae

Synthesis gas (syngas)

Water-gas shift reaction

CO2+H2 <---> CO +H2O

ΔH=41.2 kJ/mol

Ethers as Fuel additives

Octane number 116

Hydrogen - fuel of the future?

Energy from natural gas can be transferred to hydrogen with

efficiency of about 72%

The three reactions that produce hydrogen are as follows:

1. I2 + SO2 + 2 H2O → 2 HI + H2SO4 (120°C) ◦ The HI is then separated by distillation. Note that concentrated H2SO4 may react

with HI, giving I2, SO2 and H2O (backward reaction). Many chemical processes are reversible reactions, such as ammonia production from N2 and H2, but removing the desired product will shift equilibrium to the right. This reaction is sometimes referred to as Bunsen reaction.

2. 2 H2SO4 → 2 SO2 + 2 H2O + O2 (830°C) ◦ The water, SO2 and residual H2SO4 must be separated from the oxygen

byproduct by condensation. 3. 2 HI → I2 + H2 (320°C) ◦ Iodine and any accompanying water or SO2 are separated by condensation, and

the hydrogen product remains as a gas. Net reaction: 2 H2O → 2 H2 + O2 !

Storing hydrogen

Hydroelectric power

Wind energy

Geothermal energy

Nuclear Energy