(82d) Design and Analysis of the Integrated Process for Algae Conversion to Mix Alcohols

Athaley, A., Rutgers, The State University of New Jersey
Zhang, Y., Rutgers, The State University of New Jersey
Ierapetritou, M., Rutgers, The State University of New Jersey
Design and Analysis of the Integrated Process for Algae Conversion to mix Alcohols

Yue Zhang, Abhay Athaley, Marianthi Ierapetritou

Department of Chemical and Biochemical Engineering, Rutgers - The State University of New Jersey

Petroleum is the main raw material for the production of most commonly used fuels and chemicals. However, due to exhausting resources and emerging environmental issues from oil industry, alternative production paths have been investigated. Biomass sources are among the alternatives with the potential to produce both chemicals and fuels[1]. Particularly, algae has attracted a lot of interest as a third generation biomass that contains no lignin, and requires no land or fertilizer [2].

The acceptance of bio-products in the market closely relates to the competitiveness with petroleum-based products not only in terms of economics but also in terms of process sustainability. A large number of researches have focused on the biomass conversion to biofuel[3, 4] and the MixAlco® process is a widely studied bio-refining technology which can achieve this goal. The MixAlco® process can convert any biodegradable material into mixed alcohol fuels [5-7]. The ketonization route and the esterification route are the two main routes for MixAlco® process, and their economic, energy, and carbon footprint assessments have been discussed[8]. In our work, we investigate and integrate the novel fermentation process with the two downstream process to produce higher carbon alcohols with better efficiency. A synthetic syntrophic consortia of Clostridium kluyveri and Clostridium ljungdahlii is applied to the fermentation process[9-11]. The co-existence of these two microbes can enable fast and efficient utilization of carbon and electrons in the substrates by importing additional electrons as needed from H2.

This work uses techno-economic analysis and life cycle assessment to design and evaluate the production alternatives for producing mix alcohols. The detailed process flowsheet is developed and simulated using Aspen Plus. Four different routes are simulated to produce alcohol mixture: 1) Ketonization Route; 2) Ketonization with Novel Fermentation Route; 3) Esterification Route; and 4) Esterification with Novel Fermentation Route. Heat integration and economic analysis is carried out to calculate the minimum product selling price of the alcohols for each route. Sensitivity analysis is performed to analyze the bottlenecks of each route and to compare the cost of the products with fluctuating cost of algae and capacity of the plant. To check the competitiveness of the above routes in terms of sustainability, Life Cycle Analysis is carried out using SimaPro®. The results with respect to carbon production and water consumption are discussed and compared to the current oil-based processes.


  1. Bozell, J.J., Feedstocks for the future–biorefinery production of chemicals from renewable carbon. CLEAN–Soil, Air, Water, 2008. 36(8): p. 641-647.
  2. Jung, K.A., et al., Potentials of macroalgae as feedstocks for biorefinery. Bioresource Technology, 2013. 135: p. 182-190.
  3. Marchetti, J., V. Miguel, and A. Errazu, Techno-economic study of different alternatives for biodiesel production. Fuel Processing Technology, 2008. 89(8): p. 740-748.
  4. Zhang, Y.-H.P., What is vital (and not vital) to advance economically-competitive biofuels production. Process Biochemistry, 2011. 46(11): p. 2091-2110.
  5. Holtzapple, M.T., et al., Biomass conversion to mixed alcohol fuels using the MixAlco process. Applied Biochemistry and Biotechnology, 1999. 77-9: p. 609-631.
  6. Granda, C.B., et al., Carboxylate Platform: The MixAlco Process Part 2: Process Economics. Applied Biochemistry and Biotechnology, 2009. 156(1-3): p. 537-554.
  7. Pham, V., M. Holtzapple, and M. El-Halwagi, Techno-economic analysis of biomass to fuel conversion via the MixAlco process. Journal of Industrial Microbiology & Biotechnology, 2010. 37(11): p. 1157-1168.
  8. Fasahati, P. and J.J. Liu, Application of MixAlco (R) processes for mixed alcohol production from brown algae: Economic, energy, and carbon footprint assessments. Fuel Processing Technology, 2016. 144: p. 262-273.
  9. Yin, Y.N., et al., Biological caproate production by Clostridium kluyveri from ethanol and acetate as carbon sources. Bioresource Technology, 2017. 241: p. 638-644.
  10. Richter, H., et al., A Narrow pH Range Supports Butanol, Hexanol, and Octanol Production from Syngas in a Continuous Co-culture of Clostridium ljungdahlii and Clostridium kluyveri with In-Line Product Extraction. Frontiers in Microbiology, 2016. 7: p. 13.
  11. Ragsdale, S.W. and E. Pierce, Acetogenesis and the Wood–Ljungdahl pathway of CO2 fixation. Biochimica et Biophysica Acta (BBA)-Proteins and Proteomics, 2008. 1784(12): p. 1873-1898.