Parratt & Associates Scoping Biorefineries: Temperate Biomass Value Chains

Chapter 5. Biobased Products from Temperate Biomass

Biofuels and bioenergy dominate the current discussions on biobased products. A large range of government actions, nationally and internationally, seeking GHG mitigation and fuel security are responsible. Internationally the major production of biofuels has been from either corn-based starch or sugarcane. Within Australia the major sources are sugarcane, wheat residues and sweet sorghum. The rise of second-generation or lignocellulosic biomass research and development opens the opportunity to develop new products. Despite the push to develop biofuels in Australia, little attention has yet been given to the parallel development of value-added co-products.

Lignocellulosic biomass can be processed in biorefineries into a wide range of products encompassing the broad categories of fuels and energy, materials, and chemicals in a manner analogous to petroleum refineries that process crude oil. Just as with petrochemical refineries, it can be assumed that the economic sustainability of biorefineries will depend on complete utilisation of the input feedstock, requiring development of cost-effective value-added co-product streams to support the high-volume, low-value biofuel products. Current estimates suggest 10–25% of oil company revenues are derived from chemical endpoints¹⁷⁷. The top six oil companies had revenues of US$1.5T in 2009, while global shipments in chemicals were valued at US$3.7T. Significant value-add is therefore occurring between the oil refinery and the end product.

The extraction, dissociation and fractionation of lignocellulosic biomass may yield products either directly, or through additional processing of the three major substituents – i.e. the carbohydrates, cellulose and hemicelluloses, and the polyaromatic lignin, as summarised in Figure 5-1.

Figure 5-1: Example of product streams potentially available from lignocelluloses processing¹⁷⁸

5.1 Markets for Biobased Products

The global direct chemical market was approximately USD$1,200 billion in 2005, comprising 60% commodity chemicals and polymers, 30% specialty chemicals and 10% fine chemicals. Growth projections for the industry were estimated at 3% to 6% percent per year through to 2025. There is an expectation that biobased chemicals will increase from 2% of the total market in 2005 to 22% in 2025¹⁷⁹.

World peak oil predictions (Chapter 2) demand a response in terms of the potential replacement of chemicals and materials from non-fossil fuel sources. As sources of fossil based fuels are increasingly depleted (as a source of energy, chemicals and transport fuels) the demand will increase for access to and utilisation of renewable resources. Indeed, legislation is in place in US and Europe mandating increases in gross domestic energy and chemicals from renewable resources, especially biomass. Though mandates are being introduced in Australia there is no emphasis, as yet on biomass utilisation for chemicals. Current estimates suggest that biomass production in Europe and the USA could, sustainably supply virtually all of the raw materials required for the chemical industry¹⁸⁰. However, this does not detract from the possibility for Australia to be a significant supplier of platform chemicals as there is not certainty of access to the biomass in USA and Europe for chemical producers. Nor will this address the issue of trade imbalances or sustained employment in crucial industries.

5.2 Platform Biobased Chemicals

Long-term success of product substitution will depend on the development of so-called “platform chemicals” – versatile building blocks which can be used for the production of many different value-added chemicals.¹⁸¹ The opportunity to develop platform chemicals from biomass was explored in detail by the U.S. Department of Energy in two reports, the first covering chemicals from carbohydrates and Syngas (Werpy and Petersen, 2004)¹⁸² and the second examining possible routes to aromatic chemicals and materials from lignin (Bozell, et. al. 2008)¹⁸³.

However, there remain a number of factors that may impact dramatically on the development of the renewable chemical industry. These relate primarily to the early stage of the biobased industry development and are addressed in Chapter 7. The United States Department of Agriculture has examined the market potential for biobased products to 2025, and their report provides a useful guide to the scale of markets and the market sectors likely to be most relevant to biorefinery co-products in the near to medium term. The greatest future opportunity lies in biobased replacement and substitution within the chemicals and materials sector.

With the advent of lignocellulosic transformation there are considerable opportunities to utilise lignin as a base material¹⁸⁴. The Eurolignin network has identified a number of opportunities for lignin to be used as a replacement base material in a number of applications. Lignol¹⁸⁵, a Canadian-based company has been working with the Oak Ridge National Laboratories in the USA to identify potential end products for high quality lignin including its use as a platform for the development of polyarcylonitrile(PAN) as a precursor for carbon fibre. Currently approximately 1Mt/y of lignin is used as a binding and dispersing agent.

Stewart¹⁸⁶ suggests that replacement of phenolics by lignin in resins systems is economically attractive. The current phenolics market is for approximately 2.5M tonnes per annum worth approximately US$100B. Stewart also identifies the Polyolefin (PO) subsector as a potential use for lignin via integration into polymer blends and UV stabilisation. There is also a suggestion that the inclusion of lignin would enhance biodegradation of bio-polymers. The market for PO is very large with polyethylene (PE) and polypropylene (PP) representing 60% of all thermoplastics produced and sold. Global demand for PE in 2006 was in excess of 63.4M tonne.

Shen, et al¹⁸⁷ examined the potential for creating bio-plastics and the ability to deliver technical substitution on a range of products. Technical substitution is achieved when chemically identical biobased plastics replace petrochemical plastics. Shen suggests that total maximum technical substitution potential of biobased plastics and fibres is 90%, or 240M tonne of the total consumption of plastics and fibres in 2007.

Table 5-1: Technical substitution (%) potential of biobased man-made fibres (staple fibres and filament)

	PET	PA	Acrylic	Other Synthetic	Cellulosic
PLA	10%		5%		5%
PTT	20%	20%	5%		5%
PHA	5%		5%		5%
Biobased PET	65%
Biobased PA6, PA66		80%
Sum Percentages	100%	100%	15%		15%

	PET (1,000t)	PA (1,000t)	Acrylic (1,000t)	Other Synthetic (1,000t)	Cellulosic (1,000t)	Total (1,000t)	% Substitution
2007 World Fibre Consumption	30,804	3,836	2,407	575	3,081	40,703	100%
Technically replaceable volume	30,804	3,836	361	0	462	35,463	87%

PET = polyethylene terephthalate; PHA = polyhydroxyalkanoates ; PTT= Polytrimethylene terephthalate ; PA = polyamides; PLA= Polyactide ; PA6 = Polyamide; PA66=polyamide

Taking Shen’s proposition to the next stage will depend on the development of platform chemicals as detailed by the US Department of Agriculture’s report. The list of candidate platform chemicals was recently revised and updated in the light of intense ongoing research (Bozell and Petersen, 2010)¹⁸⁸. The most prospective platform chemicals and some of their potential applications are summarised in Table 5-2.

Table 5-2: Prospective biobased platform chemicals and their application areas¹⁸⁹,¹⁹⁰

Platform Chemical	Pathway from sugar	Derivatives	Potential application	Some Common Final Applications
Ethanol	Biochemical fermentation	Ethylene Acetic acid Ethyl acetate	Polyethylene Polyvinylchloride solvents	Plastic (shopping bag) Wide general use, fuel, clothing, electrical wire
Furans	chemical	Furfural Hydroxymethylfurfural Furan-2,5-dicarboxylic acid	Furanoic polyesters Polyamide	For bottles and films Boats, carbon fibre For nylons
Glycerol	Biochemical and chemical	Glyceric acid Polylactic acid analogues Propylene glycol 1,3-propane diol Polyesters and polyols epichlorohydrin	Novel polyesters PLA with improved polymer properties Sorona® fibre (DuPont) Polyurethane resins	Food Packaging Biodegradable plastic Carpets Films, filaments, engineering resins Textiles
Biohydrocarbons	Biochemical	isoprene	Rubber replacement
Lactic acid	Biochemical	Polylactic acid Lactate esters Propylene glycol	PLA polymers, e.g Natureworks® Solvents Biodegradable fibres	Plastics, packaging, Textiles, appliances
Succinic acid	Biochemical	1,4-butanediol Tetrahydofuran γ-butyrolactone	Solvents Fibres New polyesters	Housing materials, paints
Hydroxy-propionic acid	biochemical	1,3-propanediol Acrylic acid, acrylamide	Sorona® fibre (DuPont) Polymers, resins	Carpet, Food packaging plastic packaging, adhesives
Levulinic acid	Chemical	Methyl tetrahydrofuran γ-butyrolactone diphenolic acid	Fuels,Solvents,Replacement for bisphenol-A for polycarbonates	Fuels, Lunch boxes and Drink Bottles
Sorbitol	Chemical and biochemical	Isosorbide Propylene glycol Branched polysaccharides	PET like polymers Antifreeze Water soluble polymers	Drink bottles, bicycles Sportsgoods, Camping gear Protective equipment
Xylitol	Chemical and biochemical	Xylaric and xylonic acids polyols	New polymers and polyester resins	Packaging, coatings

A recent analysis by Zakzeski explores the multitude of chemical derivatives possible from lignin¹⁹¹. They concluded that the realisation of an integrated biorefinery for securing the added value of lignin over and above a waste stream requires considerable research. Specifically, the authors stress the need to identify the biomass chemistry, the pre-treatment technologies and the specific catalytic technology to perform transformations.