Biorefineries and platform chemicals

By the end you will be able to

• Describe the main chemical components of biomass and explain why oxygen, water, bulk and seasonality make it a harder feedstock than oil
• Distinguish the main biorefinery types (wet mill, whole-crop, green, lignocellulosic, two-platform and oleochemical) and what each produces
• Explain how pretreatment, enzymatic hydrolysis, fermentation, chemical catalysis, gasification, pyrolysis and transesterification work, with typical conditions and yields
• Explain how the DOE chose its twelve platform chemicals and trace the product families from glucose and glycerol
• Calculate how feedstock price and yield set cost per tonne of product, and judge why integration and by-products decide which projects survive
• Assess real cases such as corn wet milling, NatureWorks PLA, DuPont 1,3-propanediol, Braskem polyethylene and cellulosic ethanol

Contents

1. Part 1 Biomass as a chemical feedstock

   Before any biorefinery can be judged, we need to know what it is fed. Plant matter is not a green version of crude oil. It is a wet, bulky, seasonal solid made mostly of sugar polymers, with oxygen built into almost every molecule. Those three facts, composition, oxygen and logistics, explain most of what follows about yields, plant sizes and costs.

   • Plant matter is mostly sugar polymers, locked in a tough composite
   • Oil lacks oxygen; sugar carries too much, and removing it costs mass
   • Wet, bulky and seasonal: why all biomass is local
2. Part 2 The biorefinery concept and its types

   A biorefinery borrows the logic of an oil refinery: split a complex raw material into a few clean intermediate streams, then upgrade each into many products. The sources group biorefineries by feedstock and by the intermediate they standardise on. Several already exist and make money; others remain concepts. This part walks through the main types and what each one makes.

   • Fractionate first, then convert: the corn wet mill already does it
   • Whole-crop and green biorefineries use every part of the plant
   • Lignocellulosic and two-platform biorefineries: cheap feed, hard chemistry
   • The oleochemical biorefinery: the oldest and closest to petrochemistry
3. Part 3 Conversion routes: how the plants work

   Between the field and the product sit four families of process. Pretreatment and enzymes release sugars. Fermentation turns sugars into molecules. Chemical catalysis rearranges sugars directly. Heat breaks biomass into gas or oil. Each has its own conditions, yields and failure modes, and the economics of a biorefinery are set largely inside these vessels.

   • Pretreatment and enzymes: the expensive key to cellulose
   • Fermentation is judged on titre, rate and yield
   • Chemical catalysis rearranges sugars directly
   • Heat instead of microbes: gasification and pyrolysis
4. Part 4 Platform chemicals: the DOE top twelve and their families

   Petrochemistry grew from a handful of building blocks such as ethylene, propylene and benzene. In 2004 the US Department of Energy asked which sugar-derived molecules could play the same role for a biorefinery. The answer, a list of twelve, shaped research for a decade. This part explains how the list was made, the product trees it opens, and how it was revised by 2010.

   • How the DOE narrowed 300 candidates to twelve
   • The glucose platform: one sugar, many families
   • The glycerol platform: a by-product looking for a market
5. Part 5 Economics and real cases

   A biorefinery succeeds or fails on a few numbers: what the feedstock costs per tonne of product, how much of it ends up in saleable output, how big the plant can get before haulage bites, and whether by-products earn money or cost it. The cases from the sources, some successes and some closures, show these numbers at work.

   • Feedstock and yield dominate the cost of a bio-based commodity
   • Scale, integration and by-products decide who survives
   • Cases that worked: NatureWorks PLA and DuPont's 1,3-propanediol
   • Drop-ins, succinic acid and cellulosic ethanol: scale and status by 2012
6. Wrap-up Key terms, try it in the table, final quiz, sources