The results of a BioTechnology Institute (BTI) sponsored study on the potential for producing coal from algae were recently published online in ScienceDirect. The study focused on research conducted by Dr. Steve Heilmann at BTI utilizing hydrothermal carbonization (HTC), a wet process that involves ‘pressure-cooking’ the algae. This process creates a char product similar to coal that can be converted into gasoline and other chemicals or burned to generate heat and electricity.
“The advantage of the HTC process is in its simplicity,” says Heilmann. “Through basic heating under moderate pressure, we’re able to make chars of bituminous coal quality and accomplish in a half hour what takes nature millions of years.”
Dr. Heilmann, a University of Iowa graduate, retired after 34 years as a scientist with the 3M Corporation. He is an organic polymer chemist who began working on the algal coal project 2 years ago, utilizing lab space at the Biotechnology Institute at the invitation of former BTI Director Ken Valentas.
“Steve is an accomplished chemist who just had his 100th US patent issued in February,” explained Valentas, who is excited about the potential applications of Heilmann’s research in the arena of biofuels.
The advantages of producing energy from green microalgae are multiple. It carbonizes very quickly – increasing from roughly 45-70% carbon content through dehydration in just a half hour, and, as a growing plant, can double its biomass in 2-3 hours. Burning the resulting char is also carbon neutral, because the process isn’t based on any fossil fuel and doesn’t add any new carbon to the atmosphere. Greater environmental benefits also exist since the green microalgae can be used to capture carbon dioxide from the burning of fossil fuels to fuel its own growth.
According to Heilmann, large-scale success of the project will be determined by whether or not microalgae production can be ramped up and the hydrothermal carbonization process made continuous. “We’ll know within five years if algae can be farmed and whether it can capture carbon dioxide from coal-burning factories.”
An equally important area of future work on algal coal will be to find applications for byproducts of the HTC process. Filtrate from the process has potential use as a soil nutrient for both higher plants and algae because it contains nitrogen, phosphorous and potassium. Since the carbon char has a microporous structure, it also has potential as an absorbent and filler in polymers.
Others involved in the published algal coal study at the BioTechnology Institute in addition to Heilmann and Valentas included Ted Davis, Lindsey Jader, Paul Lefebvre, Michael Sadowsky, Fred Schendel, and Marc von Keitz.