Three-stage co-current gasifier separates the pyrolysis, combustion and gasification (reduction) steps. If all goes well, the result is low-tar gas (20-200 mg / Nm3).
Overview
Unlike the classical Imberts in the 1940's or FEMA (tar-makers), this type of reactor can output clean producer gas, but requires automatization with pressure sensors and high-temperature thermocouple sensors.
Operation modes
This laboratory gasifier has 4 modes of operation. 3 good, and 1 bad (which gives tarry gas, unavoidable during warmup).
Notes:
- The air must be preheated. Optimally min 400C or rather 500C. (using the exhaust heat and/or the producer gas heat in production).
- this test-reactor is too small for straw, because straw bridges easily
- on the good side, slagging was not a problem even when operating on 100% straw.
At this occasion (not always!), the middle-burner burns even with 15C air input.
Practical size
- 50-1000 kWe (200 - 3500 kWth) is a practical size for now (and multiple reactors can always run in parallel)
- 50 kWe appr 4-5 months (~ 2000 EUR / kWe inside Hungary)
- 250 kWe or bigger (~ 1800 EUR / kWe inside Hungary) on 6-8 months notice.
- the smaller 4-20 kWe seems more problematic, eg. more prone to fuel-flow "bridging" problems.
- We hope to deploy at least one 12 kWe test unit for evaluation on a friendly farm in 2011 summer, to collect fuel-bridging and fuel-tolerance experience.
- We do not expect as problem-free operation (or near as good return-of-investment) as with the 50kWe and bigger units.
- even smaller 2-4 kWe size is beyond aims for now, but not impossible in far-future