Happy new year, folks!
The aim of our first post of the year is to evaluate in an elementary manner how much energy we can extract out of a ton (literally a ton, 1000 kg) of liquid anhydrous ammonia, through its evaporation and expansion. Let us consider 1000 kg of liquid NH3 at a temperature of, say, 14°C. At that temperature, considering liquid NH3 in equilibrium with its saturated vapor, the vapor pressure is 7.045 bar and the vapor specific volume is 0.1805 m3/kg (see http://www.engineeringtoolbox.com/ammonia-d_971.html ). If we were to simply let the liquid evaporate and use the obtained vapor to drive an alternating piston mechanism similar to that of a steam locomotive, we would obtain the mechanical energy E:
E = p * V = (0.7045 MPa – 0.101325 MPa) * 180.5 m3 = 108.9 MJ = 30.2 kWh
where 180.5 is the volume of 1000 kg of saturated vapor (note that this vapor could be further expanded until its pressure reached atmospheric pressure, which means we are underestimating the producible energy) and 0.101325 MPa (megaPascal) is the atmospheric pressure.
The above basic calculation shows that from 1000 kg of liquid anhydrous ammonia we can easily extract an energy of about 30 kWh (kilowatt-hours). This sounds promising. Stay tuned for a more sophisticated analysis…
HomeMadeWatts 