industry: low cost ethanol production from bio-waste from coskata

Posted Tue, 01/29/2008 - 15:41 by shehal
this is related to a post i made few days back about ethanol for less than $1/gallon... i obtained some content from them and permission to publish... have a look at the flash presentation...
low cost ethanol production from bio-waste from coskata
courtesy: coskata

the process summarized

  1. gasification: conversion of organic material to syngas - a synthetic gas consisting of carbon monoxide and hydrogen
  2. bio-fermentation: conversion of syngas to ethanol and water from bio-chemical reactions
  3. separation: extract ethanol from water

gasification

gasification is a process which converts carbon based fuel (such as wood, coal, wood and paddy husk) to a gaseous fuel. This gaseous fuel is called syngas. the combustible components of syngas are mainly (~20% each) hydrogen (H2) and carbon monoxide (CO).

syngas composition

typical dry gas composition (%)

  • CO: 19 - 22
  • CO2: 10 - 13
  • N2: 50
  • H2: 18 - 20
  • CH4: 3

typical wet gas composition (%)

  • H2O: 8 - 10
  • CO: 17 - 12
  • CO2: 13 - 15
  • N2: 44 - 42
  • H2: 18 - 19
  • CH4: 2

chemical reactions

biomass consists of (by mass, on dry ash free basis): 50% carbon, 6% hydrogen and 44% oxygen... represented by a chemical formula: CH1.44O0.66

combustion

heat for the pyrolysis reactions and reduction reactions (see bellow) is obtained when char, tar and biomass combusts with oxygen.

C + O2 → CO2 + heat

pyrolysis

biomass is decomposed under a zero (or very low) level oxygen environment to form char and tar (and traces of methane, carbon monoxide, carbon dioxide and hydrogen which we are not too worried about as they are in minute quantities).

C + heat → char + tar + CH4 + other hydro carbons

reduction

there are several intermediate reactions which contributes in forming the syngas mixture. composition of carbon monoxide, hydrogen and methane will depend on the rates of these intermediate reactions.

C + H2O + heat → CO + H2
C + 2H2 → CH4 + heat
3H2 + CO → CH4 + H2O + heat
H2O + CO → CO2 + H2 + heat
4H2 + CO2 → CH4 + 2H2O + heat

there are other reactions which takes place, but the above reactions are the most significant.


courtesy: coskata

bio-fermentation

CO + H2 → C2H5OH + H2O

After the carbon-hydrogen bonds in the feedstock are "cracked" using gasification and converted into syngas, bacterial fermentation (biofermentation) of the syngas into ethanol occurs using proprietary Coskata microorganisms. Coskata microorganisms are extremely efficient, utilizing the entire energy value of available input material to produce ethanol. This is a significant advantage over other approaches that only use a fraction of this energy due to their inability to utilize all portions of biomass input material and/or result in non-ethanol byproducts hurting efficiencies.

click here for more info on their bio-fermentation process...

separation

After the bacterial fermentation to ethanol, the ethanol must be separated out of the solution mixture and converted into a fuel-grade ethanol at 99+% purity. As syngas fermentation leads to lower ethanol concentrations than corn fermentations, the energy and cost to separate the ethanol from water is proportionally higher. To reduce this differential, Coskata has exclusively licensed membrane separation technology to reduce the energy requirements by over 50%. The vapor permeation process is amenable to separating ethanol from biofermentation broth because of the very low solids content of the broth relative to other fermentation processes.

 

About Coskata

Coskata, Inc. is a biology-based renewable energy company, with technology for the production of liquid fuels. Using proprietary microorganisms and transformative bioreactor designs, the company will produce ethanol for under US$1.00 per gallon anywhere in the world, from almost any input material (feedstock).

Visit their Web Site at http://www.coskataenergy.com/

Comments

by kevin vaz (not verified) - 01/30/2008 - 11:37

This is totally cool! I mean this would be the best solution to our country's fuel rising problem. I hope the government will be intelligent enough to notice this technology and then implement it. I hope they wont be dumb and show a blind eye to this. We will just have to wait and see...

by shehal - 01/30/2008 - 12:03

the technology is in its research stage...
they dont have any commercial products available yet...
sri lanka has several biomass gasifiers...

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