Triage process for selecting bio-economy projects, Part III

I posted two articles on triage processes back in May 2017. Since then I have come across a very interesting approach for looking at different molecules: plotting these molecules in terms of their oxygen mass fraction (or weight percent) versus their hydrogen mass fraction.

This concept is presented by Farmer and Macal in Figure 4.12 in Chapter 4, Platform Molecules, Introduction to Chemicals from Biomass, Second Edition, James Clark and Fabien Deswarte (editors), Wiley, 2015.

I've created my own so-called Farmer plot with a selection of molecules of interest to folks active in the bio-plastics and bio-chemicals fields:



You can see that the aromatics and straight-chain hydrocarbons all fall on the X-axis, as they have varying amounts of hydrogen but no oxygen. As they come directly from petroleum, and as the petroleum industry doesn't like oxygen, this makes sense.

Bio-based compounds, by and large, are found in the middle of the chart as they contain both oxygen and hydrogen in varying quantities. The interesting part is that a number of petrochemical intermediates, such as mono-ethylene glycol (MEG), polyethylene terephthalate (PET) or phenol, are also oxygenated even though they originate from a pure hydrocarbon such as ethylene. Oxygenating the hydrocarbon precursor presumably requires some effort which may not be insignificant, and presumably occurs as late as possible in the petrochemical process.

So it is worth asking why you would deoxygenate a biobased molecule (lignin or cellulose, for instance) all the way to ethylene, only to oxygenate it back to, say, PET. (You would also have to hydrogenate to get to ethylene, then dehydrogenate.) The alternative, which the various people making furan-based compounds from glucose have figured out, is simply to shift the short distance directly from the bio-based molecule to the target (for example, glucose to PEF, which is the furanic substitute for PET), avoiding a whole lot of de- and re- oxygenation and hydrogenation which would be required if going all the way to ethylene or another of the six platform hydrocarbon molecules first.


The plot above shows phenol from lignin (the red line), as opposed to phenol from a lignin-derived benzene molecule (the two blue lines). Arguably the total distance between two molecules on the graph is an indication of the relative difficulty of converting one molecule to the other. Of course some reactions are going to be easier than others, and more chemistry will be needed to evaluate exactly what effort is needed, but may I suggest that the following equation, which uses Pythagoras' Theorem to calculate the distance between two points in a plane, would be a very quick and dirty first pass at flagging complicated chemistry, with a large value of D an indication of potentially complex chemistry:

where H and O are the hydrogen and oxygen coordinates, respectively, of the bio-based and petroleum-based molecules. So in the case above, we have the following:

• D[SW lignin to Phenol] = 0.0965 (red line)
• D[SW lignin to Benzene] + D[Benzene to Phenol] = 0.2669 + 0.1707 = 0.4376 (two blue lines)

Both approaches lead from SW lignin to phenol, but the first path is shorter by a factor of about 4.5, and (obviously!) must be a lot simpler. Certainly, for the non-chemist managerial type such as myself, it would be a flag to highlight when more questions need to be asked of the chemists.

So a question for the chemists out there: while admitting that this approach is crude, is it a sensible first pass at estimating complexity of a chemical transformation? If not, why not? Discuss amongst yourselves and report back to the plenary session.

2017 World Congress on Industrial Biotechnology

Overview

Held in Montreal on July 23-26, 2017, this was the 14th edition of this well-respected conference. Having attended many of the past editions, I can say that the material presented mirrors the maturity of the bio-chemicals industry well, and that progress towards the current level of maturity has been quite rapid over the last decade. A lot of hard work has gotten the industry to the point where it is actually making and selling commercial bio-polymers and chemicals, rather than just talking about biofuels as was the case just 5 years ago.

With 6 parallel tracks, it was impossible to cover everything. I focused on the renewable chemicals and bio-based materials sessions.

Renewable Chemicals

Several presentations focused on various furanic molecules as substitutes for aromatic molecules. Chief among these was furan dicarboxylic acid (FDCA) which can be converted to polyethylene furanoate (PEF), a substitute for petroleum-based polyethylene terephthalate (PET) in the making of clear plastic bottles.

In the same session, Stephen Roest of Corbion described Corbion's pathway, via a proprietary micro-organism, from C6 sugars to FDCA and eventually PEF. Jesper van Berkel of Synvina (a JV between Avantium and BASF) described their catalytic process to the same PEF molecule. Michael Saltzberg of Dupont described a similar catalytic pathway to a methyl ester of FDCA, called FDME. All three presenters boasted about significantly improved oxygen and carbon dioxide barrier properties when compared to the petroleum-based PET route; improved mechanical properties were also cited. These properties allow for thinner bottles or flexible food packaging, partly offsetting higher costs per kilogram, or a cheaper plastic substitute for cans or glass in high-performance applications. All claimed acceptable recyclability when mixed with PET streams, at least at low addition levels. Only Saltzberg commented on colour as a potential issue, claiming that Dupont's FDME is more stable in shipping and storage than FDCA, and thus less likely to yellow. All are planning or building commercial plants in the kilo-tonne per year range. (Corbion has the advantage of being able to swing a lactic acid plant to FDCA and back with relative ease.) Finally, REACH registration for FDCA is complete in Europe while various EPA registration processes are underway. Essentially this market is growing towards maturity, and we are well beyond the test-tube phase.

Succinic acid was also on the agenda, with mentions made of Succinity (the Corbion-BASF JV) and a presentation by Marcel Lubben, CEO of  Reverdia (a JV between Roquette and DSM). Bio-Amber. was also represented; see the section on the Sarnia Cluster below. This is another product which is reaching commercial maturity, although perhaps not as fast as some of the players might wish.

Other biomass-to-plastics processes were described by Don Wardius and Natalie Bittner of Covestro. This spin-off of Bayer's polyurethane and polycarbonate business has developed proprietary pathways from sugars to phenol and aniline, two major inputs into their production processes. The bio-conversion pathways were not described in any detail, so it isn't really possible to evaluate yields or costs, but the fact that they are willing to discuss this in public is revealing of the company's focus and intent.

In a separate session on scale-up issues, Cecil Massie of AMEC Foster Wheeler outlined six common mistakes to avoid. They are:

1. Pilot a continuous process to verify how an upset in the first unit operation is handled in subsequent units. This could be problematic. 
2. In biological processes running in very dilute conditions, the water balance will be critical. Water recovery and recycle may require expensive equipment. 
3. Heat integration and energy conservation are as important as water balances.
4. Steady state is one thing but knowing how to deal with upset conditions, especially startup and shutdown conditions, is critical. Cold starts in particular may require a lot more steam than at steady state, especially in cold climates. 
5. An early and iterative Hazop process will identify problems early. For instance, reducing risks of a spill or fire in chemical plants often requires reducing the volume of surge tanks; however this leads to downstream control problems if an upstream unit has an upset, and teh surge tank only has a few minutes retention time.
6. The actual commercial plant may be different from the pilot (e.g. filter press instead of centrifuge). Anticipate the data needed to evaluate a true commercial plant. 

Drop-in versus novel bio-based molecules

One recurring theme was the different challenges and opportunities for a drop-in molecule versus a novel molecule with new properties. The drop-in will fit into existing value chains and production facilities as it will be essentially identical in molecular structure and performance to the petroleum incumbent; the downside is that you can't really command a premium price merely on the basis of being bio-based, so it must be cost-competitive with the petroleum incumbent. This is the downfall of bio-fuels in the absence of robust government incentives (carbon taxes, renewable fuel standards, etc.)

In comparison, a molecule such as PEF, which is claimed to perform better than PET, can claim a premium price for that performance. However, downstream processes to use the molecule are not necessarily well developed, and the end-of-life issues such as recyclability or bio-degradeability may be problematic, so more work may be required to achieve significant market penetration. 

A third option is to use the bio-based material as-is at partial substitution rates. One good example is the use of lignin from kraft pulp mills as a partial substitute for phenol formaldehyde resins in the making of engineered wood products such as plywood. The lignin works well up to about 50% substitution, where failure in tension starts to occur in the glue line and not the wood; current substitution rates are quite a bit lower than this due to lower reactivity leading to increased cure times. However, unmodified lignin is cost-competitive with petroleum-based resins in this application, as long as plywood production rates are not affected by longer cure times. 

There are good examples of each of these pathways becoming commercially viable, however, so it looks like there will be different approaches for different applications.

The pulp and paper sector carries on, but stays under the radar

Representatives of CelluForce (Richard Berry), Domtar (Bruno Marcoccia) and Kruger (Balazs Tolnai) described various activities in which their firms are engaged, in the fields of novel chemicals and fibres. Progress continues and while forest sector players don't feel the need to trumpet success the way the emerging bio-products producers do, it doesn't mean nothing is going on. Celluforce is planning a new 10 t/d CNC plant (up from the current 1 t/d capacity). Domtar's lignin plant in Plymouth, NC, is sold out and they are making a plastic film made of polyethylene and 25% lignin for farm use. Kruger is making cellulose filaments for improved paper properties, polymer composites and concrete and mortar applications. 

The Sarnia Cluster

Sandy Marshall of Bio-industrial Innovation Canada chaired a session that explored the synergies available to the bio-industry in the Sarnia area. Dave Park of the Cellulosic Sugar Producers Cooperative (CSPC) described the incentive for farmers, not only to supply a cellulosic sugar plant with crop residues (corn stover and wheat straw), but also to participate in the financing and operation of the plant. In this context, Andrew Richard of Comet Biorefinery described the rationale for creating a joint venture between Comet, a technology provider, and CSPC, a feedstock provider. The first Comet plant in Sarnia, which is in the planning stage, will consume 60 kT/y of crop residues and produce approximately 27 kT (60 million pounds) of 95% pure dextrose for biochemical production. The by-product, a mix of C5 sugars and lignin, will be sold as a binder to the animal feed industry. Mike Hartmann of Bio-Amber, the eventual purchaser of Comet's cellulosic sugar, described their model for succinic acid: while it is a drop-in and chemically identical to petroleum-based succinic acid, it is cheaper and cost-competitive in North America with oil at $25/bbl. (Bio-Amber has exported to China, where it is competitive with oil at $45/bbl after transportation costs, tariffs and VAT of 17% are included.)

Bio-Amber's Sarnia plant, at 30 kT/y, is the biggest succinic acid plant worldwide, regardless of feed (bio or oil). Nonetheless, competing with an entrenched supply chain is challenging and proving the performance of the bio-based version to customers is time-consuming. However, once a customer has been signed, there is little incentive for the customer to leave due to the environmental benefits and lower cost. 

The current uses of the product, as laid out in the classic 2004 DOE report on top chemicals from biomass, are to replace adipic acid and a variety of esters, or for conversion to butanediol (BDO) and terahydrofuran (THF). Bio-Amber's growth plans include building a second plant making 100 kT/y of BDO and THF and an additional 200 kT/y of succinic acid. Meanwhile, demand continues to grow, although more slowly than hoped for; the Sarnia plant has been run at 75% of capacity, but overall sales (to over 50 companies today) are running at 35% of capacity. So although not as fast as hoped for, the growth of the succinic acid market is positive and ranks with growth of the furanic markets described above.

The Redefinery program and the Ports of Amsterdam, Rotterdam and Antwerp

In the fall of 2016 I visited a number of groups involved in a radical and ambitious program to build biorefinery plants, adjacent not to the biomass supply but to the end-user, i.e. the petro-chemical industry. This program, loosely called the Redefinery program and mirroring the Sarnia Cluster described above, is being led by industrial players in Holland, Flanders and Rhine-Westfalia, financed by these governments and by the EU, and supported by a range of R&D providers such as TNO, ECN, VITO and various local universities including Delft, Wageningen and KU Leuven. Portions of this project were described by representatives of Biorizon (Joop Groen) and Bio-Based Delta (Willem Sederel). While Canadian pulp and paper industry players might argue a pulp mill is an excellent site for a biorefinery, with existing steam and effluent treatment plants, logistics for biomass supply and product shipment, all on an existing industrial site with all the required permits in place, the same can be said of the Port of Rotterdam once you realise that several million tonnes of wood pellets flow through the port annually. Essentially the background, provided by Willem Sederel and Joop Groen, starts with a strong political desire to see a bio-chemical industry arise in the Port of Rotterdam or elsewhere in the well-integrated coastal chemical parks around the ports of Antwerp, Rotterdam and Amsterdam.

Biomass availability in and around the Port of Rotterdam consists mainly of wood pellets, as much as 8 Mt/y by 2020, imported for use in coal-fired power plants. In particular, the wood to sugar pathway, leading to organic acids such as succinic acid, lactic acid, FDCA and others, has been identified as critical by players such as Corbion, Avantium and others. The Dutch industry players have been smart enough to realize the value of bio-aromatics from lignin to the economics of second-generation sugars, and are aware that new uses for lignin will be critical if the path to sugars is to be profitable. They are spending large sums in Dutch and Flemish R&D facilities to quickly get up to speed on lignin properties and transformation processes. (The importance of bio-aromatics to the petrochemical industry is such that pathways from sugars to aromatic chemicals are also of interest.) The objective is a 0.25 to 1 Mt/y plant making sugars and lignin, probably via steam explosion, by 2019, and multiple plants shortly thereafter; budgets are up to €3.7B in industrial and EU funds over the period 2014-2020. The key players driving this very aggressive agenda are:

• The Port of Rotterdam, which has created a new 80-hectare site on reclaimed land to host bio-chemicals producers;
• RWE, who would look after pellet supply and logistics;
• Corbion, who would take C6 sugars;
• The successor to Abengoa, who would take C5 sugars for ethanol;
• Coal-fired power producers, who would initially burn lignin for fuel.

So where will the world's first million-tonne wood-based biorefinery be located? In my previous life in the Canadian pulp and paper industry, I would have hoped that a Canadian pulp mill would host (if not build and operate) such a plant; given wood supply issues, my second guess would have been Brazil. But the speed at which the Dutch are moving is such that I am now prepared to bet on Rotterdam (although the 2019 timeline is probably excessively optimistic). Stay tuned! The next World Bio-Congress will be in Philadelphia July 16-19, 2018.