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For the near future it is likely that hybrid combinations of Dividing-Wall Column distillation (DWC) and Reactive Distillation (RD), membrane and RD, and membrane and distillation will be implemented on a commercial scale in refineries and base chemicals production, as these will further reduce investment and energy cost. Hybrids is a large topic in academic research, as shown by the special issue of Chemical Engineering and Processing [1]. The advantages can be quantified by modelling as the theory is available [2]. Implementation will soon happen when technology providers develop these technologies by modelling and pilot plant validation. Sulzer Chemtech already offers hybrid membrane-distillation [3].

For the medium term future it is likely that flaring of associated gas will no longer be tolerated due to environmental pressure from governments and societies and that for remote distributed locations small scale conversion to liquid fuel by liquefaction or Fischer-Tropsch conversion to liquid hydrocarbons will be implemented. These can then be seen as small scale oil refineries. Smartly integrated reactors for the production of syngas and F-T conversion to liquid transport fuels will be implemented using compact modular design approaches. A first small scale GTL version for 20 bpd product has already been developed by the technology provider GTLCompact. It has been designed and constructed by Zeton [4] and installed at Petrobas Aracaju site in Brazil in 2011. [5]. Velocys is providing similar GTL technology [45].

In the long term the feedstock for the production of transport fuel and base chemicals may change from fossil to renewable feedstocks. Because the primary source of these feedstocks is by nature dispersed over large areas, it is beneficial to have small scale pre-treatment plants near the biomass production locations to remove water and some oxygen and so reduce transport cost. Process Intensification in combination with modular design and construction must play a major role here, as for small scale applications the cost scaling rules work favorably [6]. Sanders provides an overview of novel PI technologies in combination with novel process routes to existing novel base chemicals [7], but all these combinations of novel technologies and process routes require extensive research and development.

R&D of the last forty years has made so little progress that presently transport fuels and base chemicals from lingo-cellulose or algae cannot yet compete with products from crude oil. In my view this is for two reasons: a) The present researched processes all consume acid and base chemicals resulting in high variable cost and b) they have many process steps resulting in high investment costs.

Research is therefore recommended for small scale low cost biomass conversion to base chemicals and transport, not consuming chemicals and fully applying process intensification methods with integration of process functions in single equipment in combination with modular design and construction. Scale-up methods are available for successful implementations [8].

Only four process intensification (PI) technologies - Hydrogen Membrane separation, Reverse Flow Reactors (RFR), Dividing Wall Column distillations (DWC) and Reactive Distillations (RD) - have been implemented at a large scale in the oil refining and base chemicals. The period of their first implementation - 1977-1987 - coincides with the change in focus of chemical process industry from product innovation to process innovation, due to global concerns of competition and the environment.

These PI technologies all have considerably lower investment cost and lower energy requirements, so they fit these new requirements very well. Their success is also due to the in-house design knowledge and pilot plant test facilities of the technology providers. For the near future, it is likely that hybrid combinations such as membrane assisted distillation and reactive distillation and reactive DWC will be implemented, by which further cost and energy reductions can be obtained. Small scale plants to convert natural gas to liquid fuels at remote locations to avoid flaring will be a bit further down the line. These plants will have highly intensified technologies, and use modular design and construction methods, offsetting increased investment cost per ton of product produced, due to the low production capacity per plant.

For the long term transport fuels and base chemicals may be produced from biomass. Small scale plants at the biomass growth locations will be needed to reduce transport cost. These small scale plants will only be implemented when the investment cost per ton of product is competitive with products from fossil resources. That means that novel process routes have to be found that consume less chemicals. Highly intensified processes have to be developed with integration of steps in single equipment in combination with modular design and construction.


[1] M. Kaspereit A.A. Gorak, Special issue on hybrid and reactive separations, Chem. Eng. and Processing, 67 (2013) 1-147.
[2] A.A. Kiss, Dividing-Wall Column, in Advanced Distillation Technologies: Design, Control and Applications, John Wiley & Sons, Ltd, Chichester, UK, 2013.
[3] Sulzer Chemtech,, accessed 15.02.2016.
[4] Iain Baxter , Modular GTL as an Offshore Associated Gas Solution, presentation at Deep offshore technology Int. Amsterdam 2010, accessed 17.02.2016.
[5] J.T. Jacobs, Gas-to-Liquids Comes of Age in a World Full of Gas, JPT (2013) 68-73.
[6] C. Bramsiepe,, Low-cost small scale processing technologies for production applications in various environments - Mass produced factories, Special Issue “Chem. Eng.& Processing: Process Intensification” (2012) 32-52.
[7] J.P.M. Sanders, Process intensification in the future production of base chemicals from biomass, Special Issue “Chem. Eng.& Proc.: Process Intensification” 51 (2012) 117-136.
[8] J. Harmsen, Industrial Process Scale-up A practical innovation guide from idea to commercial implementation, Elsevier, Amsterdam, 2013.