Sugars, glycerin and other plant-derived feedstocks are emerging as economically competitive starting materials for a range of commodity chemicals, in part, the report says, because of tight supplies of conventional feedstocks such as propylene, isobutylene, butadiene and isoprene.
The shortfall is due to the shale gas boom, the report notes. North American ethylene producers have switched from petroleum-derived naphtha to lighter, natural gas-based feedstocks, reducing the output of valuable C3, C4, C5 and pygas co-products. These co-products, in turn, are the starting materials for a variety of chemical intermediates and polymers. Examples include synthetic rubber, an essential material for tire production, as well as nylon 6.6, used for fiber production and automotive parts, according to the IHS Chemical Special Report: Chemical Building Blocks from Renewables.
“Production capacity for renewable chemicals is significant, even though it accounts for a small share of overall chemical production capacity,” said Marifaith Hackett, director of specialty chemicals at IHS Chemical and the report’s lead author. “In 2013, total annual production capacity for renewably sourced chemicals was approximately 113 million metric tons (MMT), including nearly 89 MMT of ethanol capacity.”
Of the bio-based chemicals now in commercial production (excluding ethanol), fatty acids accounted for 46 percent of total global bio-based chemical production capacity in 2013, followed by sorbitol at approximately 16 percent; glycerin at 14 percent and fatty alcohols production at 11 percent. Lactic acid, furfural and several other small-volume chemicals rounded out the bio-based production capacity for 2013.
Of course, Hackett noted, capacity share varies by chemical. In some cases, bio-based chemicals account for a sliver of total (bio-based plus fossil-fuel-based) production capacity; in other cases, the most widely used production routes rely on renewable feedstocks. Bio-based ethylene, for example, accounts for a minuscule share of total production capacity. In contrast, the bulk of glycerin and fatty acid production depends on renewable feedstocks. In the case of glycerin and fatty acids, economics favor the bio-based route over the fossil fuel–based route.
“As the process technologies for these chemicals evolve, the gap between bio-based and fossil-fuel based production costs is shrinking,” Hackett said “The key is that, increasingly, processes based on renewable starting materials provide a critical alternative source of “on-purpose” production for certain chemicals that are in short supply — like butadiene. Tire and rubber producers, in particular, want to ensure stable long-term supplies of the key chemical precursors for their products, and bio-based chemicals have the potential to address that need along with offering greater price stability.”