From the Process Engineering To the Biorefinery

2nd Generation Biorefinery & Products Conversion

The class of bio-organics from 2nd generation biorefinery is defined as that which utilizes Lignocellulosic biomass as a raw material. The principal advantage of this class of biorefinery is recovery of the most abundant source of renewable carbon on the planet.

Lignocellulosic biomass is composed mainly of 3 polymers of plant cell walls: cellulose, hemicellulose, and lignin. Figure 6 shows proportions of the polymers according to plant source.

Biomass types Intermediate product Finished product
Product %Lignine %Hémic. %Cellulose Source Product
Lignocellulose Straw 8-14 24-30 31-41 a,b "BioEthanol & BTL*"
Whole plant 25-31 25-29 40-44 a,b
Wood & waste 16-24 25-35 43-47 a,b
Rémanents        
Rebus        

a http://scholar.lib.vt.edu/theses/available/etd-2998-114756/unrestricted/e-body1.pdf
b http://www.osti.gov/bridge/servlets/purl/807155-kbdGYV/native/807155.pdf

Table no.6 : Various 2nd generation biomass resources & products to BioEthanol BTL (Biomass To Liquid)

The following points could be noted as advantages of 2nd generation biorefining (lignocellulose, plant trunks, branches, and stems):

  • Significantly more abundant and diverse than 1st generation biomass
  • Reduces dependence on food crops required for 1st generation biorefineries
  • Improvement of energy and environmental cycles
  • Improved output and cost of production

Consequently, conversion of lignocellulosic biomass into bioenergy and other specific value-added products could revolutionize the Canadian pulp and paper industry. This allows the latter to diversify products, penetrate new markets, and generate substantial revenues. Within this framework, it is important to recall that chemical pulping processes are particularly suitable for partial conversion by biorefinery integration (CRIP annual report 2008).

Development of low-cost, high-yield enzymes are major issues to be tackled to ensure the feasibility of 2nd generation biorefinery.

A simplified illustration of 2nd generation biorefinery processes, using lignocelluloses as raw materials, is presented in figure 7.

Principal steps in lignocellulosic biomass conversion are:

  • Preparation of raw materials: breaking down lignocellulosic materials to expose constituent sugars (hemi-cellulose and cellulose)
  • Enzymatic hydrolysis processes for conversion of cellulose into glucose
  • Fermentation of sugars into ethanol
  • Distillation and purification of ethanol

Two industrial-scale 2nd generation biorefineries are being developed by stake and Iogen.

An illustration ofthe Iogen process is presented in figure 8.

According to figure 8, biological conversion of biomass into bioenergy requires the presence of appropriate production enzymes at close proximity of the main biomass conversion facilities. 2nd generation biorefinery constitutes one of the pricipal axes of research for the following CRIP-Biorefinery groups:

  • Professor Jean Paris
  • Professor Paul Stuart
  • Professor Michel Perrier

Figure no.7 : Production of Ethanol from lignocellulosic products. A 2nd generation Biorefinery example (source www.jgi.doe.gov)

Figure no.8 : IOGEN Process Flow Diagram (PFD), source : http://www.iogen.ca/)

Biomass to Liquid, BtL [+...]