T-Pain Is On A Boat: Re: [Electric Boats] CNG/Tri-fuel Generators?

Wednesday, July 1, 2009

Re: [Electric Boats] CNG/Tri-fuel Generators?

chris kelly wrote:
> What is CNG? is it the same as Propane?
>

Compressed Natural Gas. It's mostly Methane. The exact composition
tends to vary by the field it came from.

Liquefied Petroleum Gas (LPG) is a significant portion of Propane
(mixed with Butane), the proportions vary a bit by season and region.
LPG is a by-product of oil production/refining. Natural Gas , as the
name implies, comes out of the ground that way. (Or or less, I'm sure
it's 'cleaned' before distribution).

The two types are not quite interchangeable, LPG has a significantly
higher 'calorific' value than Natural Gas.

Where I live (Sydney, Aus) we have CNG powered buses, and LPG powered
Taxis. People occasionally convert private cars to run on LPG, and there
is infrastructure (fueling stations that supply it) due to the Taxi
industry. I'm not aware of any 'retail' CNG filling station. The buses
that use CNG have their own plant at the bus depot, hooked up to the
Natural Gas supply network. Natural Gas is piped to many homes. My home
has natural gas cooking and heating. The heater is running as I type this.
Natural Gas heaters (and cooking stoves) are unflued as the exhaust is
not toxic. (Or at least non toxic till the CO2 levels increase and the
oxygen in the room is burned :-). The gas itself is non toxic as well.
(Or at least until it displaces the Oxygen you need).

LPG cylinders are common used for gas cooking, and are so popular for
outdoor 'BBQ' cooking that there is a well developed 'swap and go'
system for distributing the gas.

Other countries have more developed CNG infrastructure and private cars
do use it instead of oil derivatives.

For my boat, it simply wouldn't be worth hacking apart my EU20i to make
it run on LPG. The gas cylinder would weigh as much as the alternator
kit, and certainly significantly more than the plastic 5L petrol
container I take my emergency supply in. Although unlike the unleaded,
ethanol blended petrol, the LPG probably won't go off over winter. :-)