Repsol YPF

LPG for generators

Electrical energy can be generated using an alternator moved by an internal combustion engine. The use of propane gas as a fuel in these electrical power units or engines provides a series of advantages which are summarised below:

• > High heating capacity
• > Clean combustion with little pollution.
• > Simple and economical system maintenance.
• > Easy regulation and parameter control.
• > Equipment with a longer life span.
• > Easily interchangeable between propane and natural gas.
• > Ease of supply.      

One of the most important characteristics for a gas used in an internal combustion engine is its knock characteristic. This is assessed using what is known as the 'methane index'. Methane, due to its high resistance to self-detonation, has been assigned the methane index of 100, whereas hydrogen, which is very susceptible to knocking, has been assigned methane index 0, with the rest of the gases falling between these two limits:

Propane has a low methane index, which means that engines must be made to work with lower pressures than for natural gas, as high pressure could cause knocking. For this reason, for the same power output, the performance level of a propane-fuelled engine is lower than that of an engine fuelled with natural gas, biogas, etc.