Tecnologia de Produção de Biochar: Características e Processos, Notas de estudo de Engenharia de Produção

Baixe Tecnologia de Produção de Biochar: Características e Processos e outras Notas de estudo em PDF para Engenharia de Produção, somente na Docsity!

Biochar^ Production

Technology Robert C. Brown

Center^ for^ Sustainable

Environmental^ Technologies Department of Mechanical^ Engineering Iowa State^ University

(^200018001600140012001000800600400) Carbon Stored (lb/acre/yr)^2000 Pyrolytic Char^ No-Till Switchgrass

No-Till Corn^ Plow-Tilled Corn Greenhouse gases reduction bycarbon storage in agricultural soils^ Char from pyrolyzing one-half of corn stover

Pit^ kiln^

Mound^ kiln

Traditional^ Charcoal

Making

Missouri‐type^ charcoal^ kiln

Continuous^ multiplehearth^ kiln

Traditional^ Charcoal

Making

Kiln Type^

Charcoal Yield*(%) Pit^

12.5- Mound^

2- Brick^

12.5- Portable Steel (TPI)

18.9-31. Concrete (Missouri)

33 Charcoal^ yields

(dry^ weight^ basis)

for

different^ kinds

of^ batch^ kilns *η=^ (m/m)^ char^ charbio Kammen, D. M., and Lew, D. J. (2005) Review of technologies for the production and use ofcharcoal, Renewable and Appropriate Energy Laboratory, Berkeley University, March 1,http://rael.berkeley.edu/files/2005/Kammen-Lew-Charcoal-2005.pdf, accessed November 17, 2007. x

Air^ emissions^

per^ kilogram^ biomass from^ different

kinds^ of^ charcoal

kilns CO^ CH^ NMHC^4 -1-1 (g kg)^ (g kg)

12 TSP-1-1 (g kg)^ (g kg) Uncontrolled^ 160-179batch

44-57^ 7-^

Low control^ 24-27batch

6.6-8.6^ 1-^

Controlled^ 8.0-8.9continuous

2.2-2.9^ 0.4-3.^

1 NMHC^ – non‐methane^ hydrocarbons

(includes^ recoverable^ methanol and^ acetic^ acid) 2 TSP^ – total^ suspended^ particulates Shafizadeh, Fred, 1982, Chemistry of pyrolysis and combustion of wood, in Sarkanen, K.V.,Tillman, D.A., and Jahns, E.C., eds., Progress in biomass conversion: London, Academic Press,p. 51–76.

Thermogravimetric analysis

of^ the

pyrolysis^ of^ plant

components

Constant^ heating^ rate^ (10°^ C/min)

with^ N^ (99.9995%)^ sweep^ gas^

at^120 ml/min Yang, H., Yan, R., Chen, H., Lee, D. H., and Zheng, C. (2007) Characteristics of hemicellulose,cellulose and lignin pyrolysis Fuel 86, 1781-1788.

Reaction^ pathways

for^ cellulose decomposition Mok, W. S. L.; Antal, M. J. Effects of Pressure on Biomass Pyrolysis. II. Heats ofReaction of Cellulose Pyrolysis. Thermochim. Acta 1983, 68, 165.

Secondary^ Charcoal

Generation

Some specific goals for advancedbiochar manufacture • Continuous^ feed^ pyrolyzers to

improve^ energy efficiency^ and^ reduce

pollution^ emissions^

associated with^ batch^ kilns • Exothermic^ operation

without^ air^ infiltration

to improve^ energy^ efficiency

and^ biochar^ yields

-^ Recovery^ of^ co‐products

to^ reduce^ pollution^ emissions and^ improve^ process

economics

-^ Control^ of^ operating

conditions^ to^ improve

biochar properties^ and^ allow

changes^ in^ co‐product

yields

-^ Feedstock^ flexibility

allowing^ both^ woody

and herbaceous^ biomass

to^ be^ converted^ to^ biochar

Preliminary^ Studies

to^ Compare^ Chars from^ Different

Thermal^ Processes Process^ Air^ filtration^

Heat Source^ Temperature Time Slow^ None^ pyrolysis

External^500 C^

30 minutes Fast^ None^ pyrolysis

External^500 C^

Few^ seconds Gasification^ 20%^ equivalence^ ratio

Combustion of^750 C^ infiltrated^ air

Few minutes

Scanning^ Electron

Micrographs Switchgrass^ Feedstock

Gasification^ Char Slow^ Pyrolysis^ Char

Fast^ Pyrolysis^ Char