Product Formation and Kinetics of the Non-Isothermal Hydrothermal Liquefaction of Soy Protein Isolate

James Sheehan - Graduate Student

Dr. Phil Savage – Adviser

The Pennsylvania State University, Department Chemical Engineering

 

Product Formation and Kinetics of the Non-isothermal Hydrothermal Liquefaction of Soy Protein Isolate

 

Hydrothermal liquefaction (HTL) is a thermochemical process capable of producing biocrude oil from biomass. HTL of various biomass feedstocks including microalgae, bacteria, lignocellulose and model compounds has been studied extensively under subcritical temperatures and long holding times (>60 min).^1–7 More recently, HTL of microalgae under rapid heating conditions and short reaction times (<1 min) has achieved higher biocrude yields achieved than HTL of microalgae under subcritical conditions and longer holding times.^8,9 Protein is a major biochemical constituent of microalgae and we performed HTL of soy protein isolate to understand better the incorporation of protein derived products into biocrude.

We conducted non-isothermal, fast HTL of soy protein isolate (SPI) at temperatures ranging 140 ^oC to 500 ^oC and residence times of 10 s to 300 s. SPI solids rapidly transform into aqueous phase products and biocrude. The highest biocrude yields (38-40wt%) were obtained within 45 s to 120 s and at temperatures ranging from 375 ^oC to 435 ^oC. The largest recovery of atomic N in the aqueous phase products was observed prior to the formation of substantial yields of biocrude. Ammonia formation was significant when the hydrothermal reaction medium reached supercritical conditions. Over 50% of the atomic N was observed as ammonia under such conditions. We developed a kinetic model and determined Arrhenius parameters that describe the fast HTL of SPI. The results of the modeling are shown in Figure 1. As can be seen, the proposed reaction network and optimized Arrhenius parameters can accurately model the major product yields from fast HTL of SPI.

Figure 1: Experimental (discrete points) and model predicted yields (continuous curves) for fast HTL of SPI at set point temperatures 400^oC.

 

 

References

(1) Valdez, P. J.; Nelson, M. C.; Wang, H. Y.; Lin, X. N.; Savage, P. E. Biomass and Bioenergy 2012, 46, 317–331.

(2) Valdez, P. J.; Nelson, M. C.; Faeth, J. L.; Wang, H. Y.; Lin, X. N.; Savage, P. E. Energy & Fuels 2014, 28 (2013), 67–75.

(3) Biller, P.; Ross, A. B. Bioresour. Technol. 2011, 102, 215–225.

(4) Teri, G.; Luo, L.; Savage, P. E. Energy & Fuels 2014, 28, 7501–7509.

(5) Changi, S.; Zhu, M.; Savage, P. E. ChemSusChem 2012, 5, 1743–1757.

(6) Luo, L.; Sheehan, J. D.; Dai, L.; Savage, P. E. ACS Sustain. Chem. Eng. 2016.

(7) Toor, S. S.; Rosendahl, L.; Rudolf, A. Energy 2011, 36 (5), 2328–2342.

(8) Faeth, J. L.; Valdez, P. J.; Savage, P. E. Energy and Fuels 2013, 27, 1391–1398.

(9) Hietala, D. C.; Faeth, J. L.; Savage, P. E. Bioresour. Technol. 2016, 214, 102–111.

James Sheehan - Graduate Student

Dr. Phil Savage – Adviser The Pennsylvania State University, Department Chemical Engineering   Product Formation and Kinetics of the Non-isothermal Hydrothermal Liquefaction of Soy Protein Isolate

 

Hydrothermal liquefaction (HTL) is a thermochemical process capable of producing biocrude oil from biomass. HTL of various biomass feedstocks including microalgae, bacteria, lignocellulose and model compounds has been studied extensively under subcritical temperatures and long holding times (>60 min).^1–7 More recently, HTL of microalgae under rapid heating conditions and short reaction times (<1 min) has achieved higher biocrude yields achieved than HTL of microalgae under subcritical conditions and longer holding times.^8,9 Protein is a major biochemical constituent of microalgae and we performed HTL of soy protein isolate to understand better the incorporation of protein derived products into biocrude. 

            We conducted non-isothermal, fast HTL of soy protein isolate (SPI) at temperatures ranging 140 ^oC to 500 ^oC and residence times of 10 s to 300 s. SPI solids rapidly transform into aqueous phase products and biocrude. The highest biocrude yields (38-40wt%) were obtained within 45 s to 120 s and at temperatures ranging from 375 ^oC to 435 ^oC. The largest recovery of atomic N in the aqueous phase products was observed prior to the formation of substantial yields of biocrude. Ammonia formation was significant when the hydrothermal reaction medium reached supercritical conditions. Over 50% of the atomic N was observed as ammonia under such conditions. We developed a kinetic model and determined Arrhenius parameters that describe the fast HTL of SPI. The results of the modeling are shown in Figure 1. As can be seen, the proposed reaction network and optimized Arrhenius parameters can accurately model the major product yields from fast HTL of SPI.

Figure 1: Experimental (discrete points) and model predicted yields (continuous curves) for fast HTL of SPI at set point temperatures 400^oC.

 

 

References

(1)      Valdez, P. J.; Nelson, M. C.; Wang, H. Y.; Lin, X. N.; Savage, P. E. Biomass and Bioenergy 2012, 46, 317–331.

(2)      Valdez, P. J.; Nelson, M. C.; Faeth, J. L.; Wang, H. Y.; Lin, X. N.; Savage, P. E. Energy & Fuels 2014, 28 (2013), 67–75.

(3)      Biller, P.; Ross, A. B. Bioresour. Technol. 2011, 102, 215–225.

(4)      Teri, G.; Luo, L.; Savage, P. E. Energy & Fuels 2014, 28, 7501–7509.

(5)      Changi, S.; Zhu, M.; Savage, P. E. ChemSusChem 2012, 5, 1743–1757.

(6)      Luo, L.; Sheehan, J. D.; Dai, L.; Savage, P. E. ACS Sustain. Chem. Eng. 2016.

(7)      Toor, S. S.; Rosendahl, L.; Rudolf, A. Energy 2011, 36 (5), 2328–2342.

(8)      Faeth, J. L.; Valdez, P. J.; Savage, P. E. Energy and Fuels 2013, 27, 1391–1398.

(9)      Hietala, D. C.; Faeth, J. L.; Savage, P. E. Bioresour. Technol. 2016, 214, 102–111.