Engine Basics
The Victory Gasifier is sized for small engines ranging up to about 30 hp. Other gasifiers use the engine to create the suction that powers the gasifier. It works, but it requires much more careful engine sizing and all but eliminates really small engines from use because they can’t deliver reliable suction through the operational changes in the gasifier. The Victory Gasifier can be used this way too, but what is preferred is to use one of our really high quality blower motors to create steady suction and let the engine use as much syngas as it wants, then use the rest for heating applications. True CHP is possible.
Which engine is best?
The ideal engine is a slow speed natural gas engine. 1800 rpm. Water cooled. Gas engines work great too. Westerbeke makes a nice slow speed engine that will last a long time, but they are expensive. Other alternatives are single and twin cylinder gensets operating at 3600 rpm. Many of these engines are rated for 3,000-5,000 hours of use. They cost less in the short term, but over the long term they can cost more if you use them often. Emergency generators are designed for standby use and not for every day operation year after year.
The beauty of the Victory Gasifier is that you can start with a small genset costing below $1000 and make reliable power at an affordable price. If you decide to make biomass your main power source consider upgrading to a heavier duty cast iron engine running at a low speed. Small car engines can fill this need running under partial load.
Getting the most out of your engine
Synthetic oil is a good idea. Hot spark plugs, like Pulstar will help with combustion speed. Advancing the timing may help as well. Electric start is a must.
Diesel Engines
Diesel engines can be used, but they will either require a mix of 20% diesel fuel (dual fueling) or a spark conversion. Diesels benefit from having higher compression and thus lower power loss.
Engine output
Syngas from the gasifier has about 50% nitrogen by volume when fed with air as opposed to pure oxygen. The nitrogen is inert and doesn’t burn, thus lowering the output of the engine by about 40% on spark engines and 15-20% on diesels, though greater efficiencies have been reached by making engine modifications or adding turbos.
Energy Conversion Tables- From Doug Williams
Based on wood moisture content of 15% wet basis
Woods gross heat energy content: 15,490kJ per kg
Woods gross heat energy content: 6,600 BTU per lb
Or 4.3kW heat per kg. Or 2.615HP per lb
Gasifiers energy conversion efficiency: 73.57% HOT GAS
Gasifiers energy conversion efficiency: 70.95% COLD GAS
AFTER GASIFICATION
Gas produced from 1kg of wood: 2.185 standard cubic metres
Gas produced from 1lb of wood: 35 standard cubic feet
Energy content of 1 standard cubic metre of gas: 5,030kJ
Energy content of 1 standard cubic foot of gas: 135 BTU
After gasification 1kg wood yields 2.185 cubic metres of gas which has a net heat energy content of 3.05kW heat.
After gasification 1lb wood yields 35 cubic feet of gas which has a net heat energy content of 1.8566HP heat. (Or 4,725 BTU)
1kg of wood produces 2.185 cubic metres of gas
or 3.165kW heat from burning gas direct
or 0.837kW of shaft power i.e engine
or 0.754kW of electric power generated
1lb of wood produces 35 cubic feet of gas
or 4,900 BTU heat from burning the gas direct
or 1.925HP heat from burning the gas direct
or 0.51 HP of shaft power i.e engine
or 0.459HP of electric power generated
or 0.342kW of electric power generated
1 litre of diesel has a heat energy content of 9.630 kW heat (or 32,895 BTU)
1 litre of petrol as a heat energy content of 8.79 kW heat (or 30,023 BTU)
1 litre of diesel has the same heat energy content as the cold gas from 3.1579kg of wood
1 litre of petrol has the same heat energy content as the cold gas from 2.882kg of wood
