1.  No fertilisers needed
Investigating Methods for the Direct Liquefaction of Algae Project Partners: G. Finnerty & K. Parmar. Supervisors: Dr. A.B. Ross & Dr. P. Biller
1 Introduction
4.2 Bio Oil Analysis
 All bio-oils HHV were relatively constant, at 37 MJ/kg comparable to crude-oil at 41 MJ/kg 2.
Carbon neutral biofuels have received greater interest recently due to concerns regarding the effects of the continued use of fossil fuels has on the climate1. Third generation biomass have the advantage of not competing with land and production of food. Macro and microalgae based biofuels represent some of the most promising alternatives.
 Chlorella bio-oils have greater amounts of carbon and nitrogen contents, especially from HTL. These would have to upgraded, negatively impacting end-yields.
 Pyrolysis bio-oils require less further upgrading.
Macroalgae
Microalgae
 Lower ash and salt content
 No need for grinding
 Better for landlocked countries
 Easier growth control
 Higher HHV
 Easier to genetically manipulate
 Higher lipid content
 Can use Industrial Wastewater
 No added water required
 No land required
 Simpler to cultivate
 Less pests/invasive species issues
 No fertilisers needed
 Fast growing
 No food vs fuel debate
 Bio-oils produced are complex mixtures with varying compounds. An example of a chromatogram is shown on the right, with were these compounds are found.
 Chlorella mostly comprised of lipids and proteins.
 Laminaria mostly consists of carbohydrates and proteins.
(a)
(b)
2 Materials and Methodology
4.3 Char Analysis
4.5 Carbon Balance
Two techniques used in this study were pyrolysis and hydrothermal liquefaction (HTL). Different experimental setups allowed for various heating rates. Laminaria Saccharina and Chlorella Vulgaris were chosen as the macroalgae and microalgae feedstock respectively.
3. Ross, A.B., Anatasakis, K., Kuacki, M and Jones, J.M. (2009). Investigation of the pyrolysis behaviour of brown algae before and after pre-treatment using Py-GC/MS and TGA J. Anal. Appl. Pyrolysis. 85, p.3-10.
1. IPCC. (2013): Climate Change 2013: The Physical Science Basis. Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press,UK.
2. Speight, J.G., (2001). Handbook of Petroleum Analysis, first ed. Wiley-Interscience.
References
Most of the carbon in pyrolysis products were found in the char residue, shown above. For the Laminaria HTL process; larger amounts of carbon remained in the process. Chlorella generally had more of its carbon in the bio-oil, as expected from elemental analysis. It seems that Chlorella undergoing HTL is the preferred process for minimising any waste carbon in other co-products. .
3 Feedstock Analysis
Ultimate and proximate analysis enabled a comparison of the chemical contents in the feedstock. N and carbon (C) were most abundant in Chlorella, whilst oxygen (O) content was highest for seaweed. Analytical pyrolysis was conducted to understand the compounds present in the original feedstock. This helped to
The graph above illustrates pyrolysis bio-chars from Chlorella achieved the greatest calorific values owing their carbon contents. However, problems arise as they contain high nitrogen contents if utilised for combustion. HTL chars exhibit lower nitrogen as it is displaced in the process water. These bio-chars could be valorised for domestic use or be utilised to remediate soil.
understand the following by-product chemical compositions.
4.4 Aqueous Phase Analysis
5 Conclusions and Further Work
 It was found that the SHR processes produced the greatest amounts of bio oil; most abundant in the HTL process.
 Bio-oil HHV’s remained relatively constant across the various techniques.  The gas and solid phases could be utilised and valorised by combusting them to generate heat for the process, char could be used as a fertiliser; process water could be utilised for nutrient recycling for further cultivation of microalgae.
 Further work includes; removing N across the co-products, or recycling it, and investigating hydrothermal carbonisation of other wet feedstocks.  Pre-treatment methods could be explored to minimise metal content of oil.
Elemental analysis was performed on the aqueous phase residue shown below. Chlorella had the most C and N dissolved in the process water. The high O content in the Laminaria may be due to the presence
4.1 Yields
 The microalgae was found to produce more bio-oil than seaweed in all scenarios, as expected, due to its high lipid content.
 Laminaria produced the greatest aqueous phase residue yield. Therefore this feedstock has the largest potential to be utilised for nutrient recycling.
 Gas yields were only determined for the fast heating rate experiments due to equipment limitations.
 No bio-oil collected for pyrolysis FHR, probably due to equipment failure.
Of trace metals (e.g. K, Mg, Na, Ca)3 which are unaccounted for.
This analysis would aid understanding of cultivation growth patterns when using process water.