[Gasification] water injection of producer gas fired ic engines

[Ken Boak]

Gents,

Some interesting comments regarding water injection.  If too much water in
the biomass causes a shift from CO to CO2 production, then why not introduce
water vapour directly to the air intake of the engine?

I believe that the expansion of the water vapour in the cylinder will
increase the downward force on the piston during the expansion stroke, and
also help remove some heat from the cylinder walls.

In a veg-oil fuelled diesel, I have also heard, though yet to confirm, that
it is beneficial in reducing the amount of carbon build up in the combustion
chamber.

As a simple experiment, I can introduce some steam directly into the air
intake of my 6hp veg-oil fuelled Lister, and note any performance change.

I have a nominal 3kW load attached, and I can measure any change in rpm or
voltage produced.

I can also measure the exhaust gas temperature to see if it is lowered when
the water is introduced.

I have noticed better performance on days of higher humidity, and also when
the ambient temperature is around 20 C, rather than last week when it was 30
C.

If steam introduced via the air intake is beneficial to performance, then
there is no shortage of water available from the biomass, which in my case
is woodchips with up to 25% MC before the drying process.

At 650rpm I am seeing temperatures of 352 C  (666F) at the exhaust manifold.
The engine is running quite hot, with the coolant close to 98 C at the water
outlet in the cylinder head.



Ken