Reaction Engineering of Hydrothermal Liquefaction to Produce Microalgal Biocrude

EPA Grant Number: FP917507
Title: Reaction Engineering of Hydrothermal Liquefaction to Produce Microalgal Biocrude
Investigators: Valdez, Peter J
Institution: University of Michigan
EPA Project Officer: Lee, Sonja
Project Period: September 1, 2012 through August 31, 2015
Project Amount: $126,000
RFA: STAR Graduate Fellowships (2012) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Fellowship - Chemical Engineering


The goal of this research is to understand the reaction network and kinetics of the hydrothermal liquefaction of microalgae. A systematic study of liquefaction will help to identify reaction pathways and products that improve the quality and yield of the desirable biocrude, while elucidating how to control the formation of byproducts that could potentially harm the environment.


The processing conditions related to the liquefaction of microalgae will be studied, the products characterized and a global model using empirical data developed. The study will investigate how the composition of lipids, carbohydrates and proteins in the feedstock and processing conditions of liquefaction affect the yield and composition of all of the products, not just the biocrude. The study will characterize the products to understand how they change with respect to processing parameters, enabling the design of a model to predict the results. A systematic study of hydrothermal liquefaction will allow modeling of the outcome using reaction networks and global kinetic modeling. With an understanding of how to engineer microalgal biocrude, liquefaction reactors can be designed readily for regional and seasonal feedstock supplies, including other biomass feedstocks, to produce a valuable energy carrier.

Expected Results:

This research will focus on understanding how to engineer the composition of microalgal biocrude by studying processing conditions that positively affect product results. There are several hypothesized benefits of this research. A systematic study of microalgae liquefaction will provide a fundamental knowledge of what to expect regarding product composition and yield. Ultimately, the model will not only predict the biocrude composition, but also the composition of all of the liquefaction products, including the gas phase, water-soluble products and the solid residues. Understanding the distribution of products will be useful for optimization of product and byproduct utilization, ideally reusing the byproducts to cultivate more biomass. An additional benefit will be to gain knowledge of how to prevent the formation of hazardous compounds during processing. The model derived from this research should define the optimum conditions for improved product characteristics, identifying the conditions for a high yield, high energy, low heteroatom, low viscosity biocrude. The ideal biocrude composition should be coupled with a mix of byproducts that are nontoxic and reusable for processing. Once a firm understanding is established about the capabilities of hydrothermal liquefaction, it will be easier to determine the next steps for the recovery and reuse of the liquefaction byproducts at a laboratory and industrial scale. With a complete model, it will be possible to extend the predictions to other biomass feedstocks. The ultimate result of this research should significantly contribute to the field of algae to liquid fuel conversions by providing key information for process designers and prepare the technology for widespread public use and development.

Potential to Further Environmental/Human Health Protection

As new biomass-conversion technologies are developed to help supplement the demand for renewable fuels, the environmental impact of the byproducts from such processes can be sometimes overlooked. For microalgal processing, it is especially important to know the fate of compounds that are known to cause damage to the environment, specifically phosphorus- and nitrogen-containing compounds that are needed for microalgal cultivation. High temperature reactions also can produce compounds that are not typically found in nature and can be harmful if released into the environment. This research will help to elucidate the fate of these and other potentially hazardous compounds during processing.

Supplemental Keywords:

hydrothermal liquefaction, biofuel, renewable energy

Progress and Final Reports:

  • 2013
  • 2014
  • Final