Petroleum is a limited resource and if we keep using it global warming will accelerate. Since this realization has filtered in the quest for alternatives has begun. Shale gas and natural gas are only pseudo solutions as those supplies are finite and fossil, too. The only way out are fossil-free resources, bio-based ones that is. Industry and academia are developing bio-based processes fervently and with the prerequisite that the products must not be more expensive than conventional ones.

All around the world times are hard for bio-based chemicals as they can rarely compete with their fossil counterparts pricewise and cannot even play a trump card in the matter of climate change. Of the total energy demand worldwide the chemical industry uses 30% and it is responsible for 20% of the industrial greenhouse gas emissions. In comparison, the amount of “C” that ends up as part of products is marginal. Consequently energy consumption is the main area to target if CO2 emissions shall be significantly reduced. Nonetheless, support for bio-based products is firmly anchored in the policies of many governments and the targets they have set are ambitious.

Bio-based policies in Europe and the US

There is consensus in the EU and the US that guidelines on how to switch over to a bio-based economy need to be stipulated; the approaches to implement the change are quite different regarding the strategies of the different governments and the legislative conditions.

The European Union has agreed upon:

• a 40% greenhouse gas reduction by 2030 (compared to 1990 levels)
• at least a 27% share of renewable energy consumption
• at least 27% energy savings

More explicitly 20% of the chemicals and materials in the European Union will be bio-based by 2020, rising to a quarter in 2030.

In the United States the Biomass R&D board envisions a billion ton bioeconomy. By 2030 one billion tons of biomass is projected to be sustainably produced.

Plainly spoken this means biofuel in the forms of biodiesel or the addition of ethanol to gasoline.

Which is the most promising bio-based chemical?

In 2004 the US National Renewable Energy Laboratory (NREL) has defined twelve top value added chemicals from biomass. These products seemed to be the most promising at that time but a lot has happened in the last decade. In the follow-up report of 2016 there is again a list of twelve promising chemicals. The overlap between the two lists is moderate and consists of glycerol, succinic acid and para-xylene. 

The EU, too, strives to identify the chemicals that are predestined to be made from biomass. RoadToBio is a EU-funded project set up in mid-2017 to deliver a roadmap by 2019 illustrating the ‘sweet spots’ for Europe’s chemical industry. In a first step, a long list with 120 chemicals at TRL 6 or higher was compiled that show potential for the chemicals market. In parallel, the value chains of 500 petrochemicals were analyzed from a purely technical point of view. 85% of the value chains offer entry points where a petrochemical could be replaced by a bio-based one. The chemicals that were cited most often as replacable are ethylene, propylene and methanol.  

RoadToBio analyses the interface between bio-based and petrochemical

The NREL report and RoadToBio project have in common that they both examine products with a technology readiness level of 6 (TRL 6) or greater meaning that the production process has reached pilot scale. Furthermore the studies so far both work along the value chain of petrochemical products.

Whenever a chemical can in theory been replaced by a bio-based one this is called an entry point in RoadToBio. Overall, of the 120 chemicals identified in the long list for further analysis, only 49 have entry points into existing petrochemical value chains, while the other 71 are dedicated chemicals. Dedicated chemicals are those which have no fossil-based counterpart and thus offer unique production routes. Lactic acid as base for the bioplastic polylactic acid is a prominent example for a dedicated chemical. In contrast, drop-inchemicals  are bio-based versions of existing chemicals . A third group, smart drop-in chemicals, are also chemically identical to their fossil counterparts but provide an additional advantage compared to ordinary drop-ins. This can be a faster and simpler production pathway or less energy use.

In the NREL analysis some products such as ethylene and methanol were consciously excluded as they would compete with chemicals derived from natural gas, which is not realistic. It remains to be seen if RoadToBio researchers take a similar route in the next step, in which they will analyze drop-ins and dedicated chemicals for their market potential.
Four chemicals that appear on both the top twelve NREL list and among the 49 RoadToBio chemicals with potential entry points are succinic acid, para-xylene, 1,2-propanediol and glycerol.

More details on www.achema.de