James Madison U - Design, Construction, Testing and Deployment of Biochar Reactor - Open 2011
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James Madison U - Design, Construction, Testing and Deployment of Biochar Reactor - Open 2011
- 1. Design, Construction, Testing, and Deployment of a Biochar Reactor: A Student Capstone Project Robert Prins and Wayne Teel James Madison University
- 4. why should we care?
- 5. how is biochar produced?
- 7. Historical usage dates to 450 BC
- 8. Terra preta sites in the Amazon
- 12. High cation exchange rateFeltz, 2010 Feltz, 2010
- 14. Plant based carbon is unstable, plant decay releases carbon to atmosphere
- 15. Biochar can remain in soil for 1000s of yearsJ. Lehmann, “Black is the New Green”, Nature, Vol 442, 10 August, 2006
- 17. Heating in the absence of oxygen
- 18. Initial heating drives off water vapor (100 C)
- 19. Further heating (~350 C +) drives volatiles out of carbon structure
- 20. synthesis gas (H2, CO, CO2 )Glaser, 2007
- 23. Meets ISAT capstone project best practices:
- 25. Situated in a relevant social context
- 27. 2 students, FA08 – SP09
- 31. 4 students, FA09 – SP10
- 32. Final design
- 35. Syngas from feedstock is used to supplement heat source
- 37. JMU Biochar Processor 1 36” 51 1/2” 15” 54 1/2” 38 1/4” 3 2 4
- 38. JMU Biochar Processor Data
- 41. Porosity
- 42. Density
- 43. Cation exchange
- 44. Biochar is produced from biomass via pyrolysis
- 45. Student project to develop a low cost processor was successful
- 46. Produced biochar (21% mass retention)
- 49. Improve sealing of outer chamber (roof, door)
- 50. Improve sealing on inner chamber door
- 51. Increase robustness of chamber walls
- 52. Improve heat recovery system
- 53. Gen. 2.5
Notas do Editor
- Pyrolysis refers to heating a material –in this case biomass- past its combustion temperature in the absence of oxygen (so it doesn’t burn)Biochar is essentially the carbon matrix that remains after moisture and volatile compounds are driven off of biomassTerra preta sites (Portuguese for “dark earth”), researched by WimSombroek in the 60’s, include 2m deep sections of soil with significantly elevated charcoal content. It is widely believed that the soil was the product of indigenous soil management in which a “slash and char” technique was employed to improve the soil.It has been shown to improve soil conditionsProduce a valuable product (improve soil conditions, offset need for additional soil amendments)Sequester carbon (carbon structure stays intact for 1000’s of years vs. shorter term decay in landfill)
- We use pine lumber as a precursor so essentially the biochar we produce is charred wood. The wood structure remains intact during the charring process, although excessive heat would produce ash instead of char. Note the growth rings. Lab experiments with temperature controlled processing as part of a parallel project indicated that we had broad temperature leeway with our feedstock. (400 – 600 C)
- High microporosity: habitat for soil microbes and mychorizal fungi, host for soil nutrients (less apt to leach out)Low density: promotes root penetration and moisture retentionDensity 0.2 – 0.8 g/cc750 – 1369 m2/g High cation exchange rate: biochar is negatively charged – it is instrumental in the uptake of positively charged cations from the soil to the plant. Cations include nutrients such as potassium, magnesium, and calcium which are essential for plant growth
- Picture shows biochar enriched soil from a long time ago – biochar sites date back to 450 BC
- Approximate pyrolysis; use the water vapor phase to displace air (oxygen): allows for use of an inexpensive chamber
- A farm-scale reactor is small enough that students can design and build the whole thingThe scale encourages a low-cost approach that emphasizes readily available materialsThis project dovetails with faculty agendas of biochar related research and production, and provision of hands-on intensive projects for students.
- During independent study phase “behind the scenes” work went into finding an implementation siteUltimate success of project was built on independent study and faculty activities
- Wood destined for landfill is used as biochar feedstock and process fuelFeedstock is converted to biocharSyngas from feedstock is used to supplement fuelSome process heat is recovered for short-term use as space heat or pond heat
- Chamber within chamber designA wood fire in the outer chamber heats the inner chamberAs the biomass (wood) in the inner chamber heats up, water vapor is driven off which displaces the air (and oxygen) in the inner chamberAs gasification occurs, syngas from the wood is plumbed to the fire to supplement the heat sourceRudimentary waste heat capture via water tube on roof (~25 MJ recovered vs. 450 MJ input from 15 kJ/g wood)The biomass is processed to biochar with a net mass retention (fuel source and feedstock) of ~21%Typically 15 kg of feedstock and 15 kg of fire wood are required to produce 7 kg biochar
- Inner chamber is a 30 gallon barrel ($62) plus $30 for the plumbing suppliesGrate is made of steel stock (flat bar and angle iron) ($50)
- Block base was donated but cost would be $50Fire brick walls $450Roof plate $105Floor plate $30Door plate $30
- A thermocouple in the pyrolysis chamber tells the story:Initially the fire heats the chamber contents and drives off water vapor (notice the leveling off near 100 C)Chamber contents continue to heat up until volatiles are driven offNote syngas combustion around door of chamberThis version was prone to heat loss (even with door in place)
- Syngas pressure in the drum varies.Once the off-gassing process is established the pressure is high and results in jet-like flames. As the process continues and most of the off-gassing has occurred the pressure is reduced and the resulting flames are candle-like.
- Biochar is likely to offset requirement for additional soil amendments because it is capable of retaining nutrients in its structurePyrolysis process can be approximated using inexpensive approachStudent processor required $800 in materialsDemonstrates - usage of waste stream materials as fuel and feedstock - produces biochar - sequesters carbon from feedstock - potential for process heat recovery as space heat or hydroponic pond heat
- A thermocouple in the pyrolysis chamber tells the story:Initially the fire heats the chamber contents and drives off water vapor (notice the leveling off near 100 C)Chamber contents continue to heat up until volatiles are driven off
- A thermocouple in the pyrolysis chamber tells the story:Initially the fire heats the chamber contents and drives off water vapor (notice the leveling off near 100 C)Chamber contents continue to heat up until volatiles are driven off