The Economist – Technology Quarterly – September 2013′

Biofuels, their Future and this Little Island 

 

‘With reference to the article ‘What happened to biofuels?’

This gives an interesting insight into some current activities and issues in the field, but seems to us a little too restricted in its view.

The real problem is actually larger than that of addressing Global Warming or Climate Change, though benefits from biofuels will obviously accrue here. Indeed those that emphasize this facet may be tacitly admitting their process will not be economic unless supported by carbon credits or other subsidies. Nor is the problem one of simply producing a liquid transport fuel.

The real problem is that of replacing crude oil, in all its myriad uses, because oil is being rapidly depleted and prices will remain high – and go higher – until there is an effective, economic and comprehensive replacement.

Replacement of crude oil is feasible sustainably and at zero or even negative carbon, with biomass, given the right fractionation and conversion technology. There is already sufficient waste and unused biomass available globally for 10 billion barrels per year of oil equivalent – roughly one-third of current crude oil production. By planting to create more, this could rather easily be doubled – and this would provide for the world’s entire projected need for liquid transportation fuels. But doing this economically requires very large scale processes, with high yields and energy efficiencies – and the capability to produce not only fuel products but the valuable platform chemicals, so that each possible fraction of value from the feedstock cells is efficiently extracted.

At present, all the technologies discussed in your article fail to meet these requirements. For example, several of the “latest” technologies referred to rely on enzymatic fermentation. These processes are typically discontinuous batch, small in scale, and thus inherently expensive – their cost being exacerbated by the fact that they normally use impure sugars from only partially unfractionated biomass as feedstock, which themselves poison the enzymes so the latter need continual expensive renewal. You also mention a “fast” pyrolytic process, which is at least a step in the right direction, but does not allow clean progressive cell fractionation and hence produces a pyrolysis product of fearsome complexity. So though a laudable innovation it is not surprising it is having economic difficulties.

We firmly believe the answer lies in continuous, phased, progressive physical then thermochemical fractionation then reforming of lignocellulose – waste or woody material, not food such as sugar or wheat – into all its valuable recoverable fractions, followed by the use of the final output lignin char (the equivalent of the oil refiners’ “black bottoms”) for electricity generation or to be put back into the land. There it has massively beneficial effects for reclamation and improvement – and sequesters carbon rendering the whole process carbon negative.

Excitingly, all the necessary components of such a process have already been proven at laboratory or pilot scale and we are well advanced in our plans to raise the funds for and construct a pre-commercial demonstration plant putting the process into practice at significant scale on Teesside over the next two years. This will lead on to full product slate/large scale plants of similar scale to 5000-6000 bbl/day oil refineries – an order of magnitude larger than even the largest plants your article describes. These should be massively profitable even at low oil prices in the range of $50/bbl. They are already feedable with outputs from existing forests, or the waste from large sugar cane or palm oil plantations. Subsequently even larger deployments are possible, and we believe there are solutions to the logistic issues involved.

A final further piece of good news is that the process has been developed by British chemical engineers and so there is a very good chance of our “little island” leading the world in the development and deployment of “the” technology which will substitute sustainable sources for fossil oil in the future. So David Cameron may be able to add another verse to his recent song!

 

 

Peter H. North, M.A. (Cantab.), BA (OU), C Eng., FI Chem. E, Technical Director

Barry D Hedley, MA (Cantab), MBA (Harvard), C Eng., MIET, Chairman

 

Nova Pangaea Technologies Limited


ADDITIONAL NOTES

 

Scale. The occasional ‘giant’ oil field discoveries still being heralded are of little significance on a global scale – oil consumption is some 30 billion barrels a year, so it requires 5 discoveries of 6 billion barrels of recoverable oil per year, every year, to keep up and this is not happening. And ‘fracking’ gas will be used to replace coal and nuclear fuel for static power generation – but reserves have probably been greatly overstated in light of problematic geologies and over-estimation of ultimate recovery potential. It is unwise to assume a continuous level of technological advancement, when estimating reserves – a common practice in the oil and gas industry.

 

Importance of Chemicals. The chemical products are extremely important long term – for they are typically significantly more valuable than fuels. With 25% of oil currently going to chemicals, the market is enormous – and, because of the higher oxygen content of biomass products, the chemicals market is a better fit than fuels to some extent. For the next few decades, both oil and biomass derived products must coexist, so that it makes sense to play to their respective strengths – although biomass products, despite their oxygen, can be fed into refinery streams to some extent.

 

Logistics & “Distributed” versus Scale Plants. A second error, again made by most process developers, concerns the limitations imposed by logistics, also noted in the article. But this is fallacious, a remnant from early studies on US, seasonal crop based, 1st. generation concepts. When feedstock requirements, and supplies, are 365 days per year, existing logistics infrastructure (road and rail, primarily) must be replaced or supplemented by dedicated, low cost materials transport systems – thereby significantly increasing the areas available to serve a processing facility. The emphasis given by many developers to distributed facilities, reducing logistic requirements, reflects more on the inherent limitations of their technologies than on any real advantages. A major component of any process, unless co-located with existing refinery or chemicals plants, will be the power (and heat) plant and this will cost proportionately more for a small plant, damaging overall economics In any case, distributed plants also require a complete infrastructure and consume a great deal more materials in their construction, proportionate to output. A proper Life Cycle Analysis would demonstrate many of the weaknesses.

 

In addition, for continuous, high density feedstock supplies, the best locations are in the tropics – and this is where the bulk of facilities will be located (very large scale, at least). Other major areas will include the extensive northern temperate forests, though biomass harvest densities will be lower.

 

NPT: The Best Technology. The Nova Pangaea approach has been to develop a staged, progressive, physical then thermochemical fractionation and conversion process. The concept from the beginning has been to find ways to extract all potential valuable fractions from the input lignocellulosic cells. This has the further advantage that by first removing complex fractions physically, then applying only gentle thermochemical reactions and only finally the most aggressive pyrolytic reaction (actually a sophisticated process step more appropriately termed “steam thermolysis”), each stage is enabled to operate efficiently without contamination from earlier ones poisoning the process and producing valueless process-clogging compounds. Furthermore, the process is inherently simple, using well known industrial techniques and involving no active agents (such as enzymes) or catalysts (such as acids). This reduces cost, and also means no effluent problems occur. Indeed, if desired the process can be set up to produce potable water from the water content of the input biomass, as it operates directly on green or “wet” biomass as delivered from the field. This is in itself a tremendous advantage, as many other processes require drying of the feed – and then only too frequently proceed to subsequent unit operations carried out in dilute suspensions, with further water extraction being required later. This massively damages their internal energy efficiency. Finally – an overwhelming advantage. The NPT process is pretty much alone in being a “tubular”, continuous process – and thus almost infinitely scalable. This affords very significant capital and operating cost advantages over other processes which are typically batch or semi-batch in nature. It will enable fully oil scale (and hence low cost) biorefinery operations to be deployed.

 

As a result, the NPT technology emerges as superior to others in use on all counts – quality of product, full range of product and hence value, and low cost. Our calculations show it should be capable of oil equivalent costs of $12 per barrel (at zero – i.e., “waste” – feedstock cost) to $42 per barrel at $84 per tonne (energy equivalent cost) of delivered feedstock. Obviously a good safety margin then exists for its economics – without government subsidy or carbon credits. And if applied in soil reclamation mode – where the output lignin char is used for land improvement, the process becomes carbon negative. Imagine, we can continue to use our existing, internal combustion engine driven vehicles – and every mile we drive we shall sequester net carbon, not emit it!

 

Impact on Agriculture. The final, major, point is that large scale, global utilization of ligno-cellulose will transform global agriculture, because it gives significant value to residues that are currently of low or even negative value, and will lead to a virtuous cycle – increased farm incomes enabling increased fertilizer use and better seeds or trees, leading to increased crops (and associated biomass) and a further increase in farm incomes. Our work suggests that crop yields in the tropics can be increased by a factor of 2 or 3 fairly easily and that farm incomes could rise by a factor of 5-10, albeit over 30-40 years. The need for year round feedstock also provides an incentive to move away from monoculture and back to mixed crops and crop rotation – improving soils and reducing agricultural chemical use and costs.

 

 

No comments yet.

Leave a Reply