SequesChar
Growing up with a soil scientist as a Dad, I was exposed to more information about dirt than most kids may have liked. Even so, the stories of his years in Africa working to help their local crop Sorghum thrive in the arid climate left a lasting impression. Later in my teenage years through an odd job I was introduced to biochar, an interesting soil amendment which also happens to sequester carbon from the atmosphere. Naturally, I was very interested. As I was approaching my final year of my B.S. Mechanical Engineering, I was brainstorming for a biochar related capstone project. Having just turned 21 it was no surprise when beer was the answer.
Brewers Spent Grain
Brewing has been around for over seven thousand years, and to this day beer remains the third most consumed beverage behind coffee and tea. Throughout the world in 2019, 1.91 billion hectoliters of beer were produced. The most significant waste stream from the brewing process is brewers' spent grain (BSG) accounting for 85% of the physical waste produced. There is an estimated 38.6 million tonnes of wet spent grain produced annually.
What Happens To Spent Grain
Spent grain is shipped to farms for animal feed, composted, or sent to a landfill. This results in greenhouse gas emissions from the transportation, as well as the decomposition or digestion of the wet grain. In some cases this will also result in additional disposal costs for the brewers, especially if there is no nearby farmland. Spent grain must be disposed of within 2-3 days to prevent unwanted in-house decomposition.
"Pyrolysis (pī-rä’-la-sis), the process of heating biomass (wood, manure, crop residues, solid waste, etc.) with limited to no oxygen in a specially designed furnace capturing all emissions, gases, and oils for reuse as energy. "
SequesChar is pursuing an alternative treatment of spent grain using pyrolysis, the thermal decomposition of biomass or a solid fuel in the absence of oxygen to produce biochar and flammable pyrolysis gases. We plan to turn this low value, cumbersome byproduct of brewing into environmentally friendly and economically beneficial resources.
SequesChar as a Senior Capstone
Beginning in the Winter of 2020 I began researching for pyrolysis of brewers spent grain. I read journals, textbooks, forums, and wrote my final research paper on pyrolyzing brewers' spent grain for energy and biochar.
In the fall of 2021 I formed a team and began a year long senior design project along with four other engineering undergraduates and one graduate student. In the spring, in addition to continuing to lead this project, I sponsored a semester long design team who designed and fabricated an air tight continuous feed system for our pyrolysis chamber.
In the spring of 2022 we fabricated the system on a $500 budget as shown below. The contents are heated to 450 degrees Celsius and fed through the system by the rotating paddles shown on the left. The plates on each level will be electrically heated using nickel chromium wire. There will be a PLC attached to a thermocouple to control temperature. The insulation is alumina silica, the plates are cast from alumina, and the shaft and paddles are steel. The base and top are temporary as it is designed to be continuous feed once the continuous inlet and outlet is designed.
Using this idea I won $500 in a UMass Amherst Pitch competition in the Fall of 2021. Then I won $21,000 in the Spring of 2022.
SequesChar Post-Graduation
Above is my most recent design of the pyrolysis system. I am currently working with a contract manufacturer in Eastern Massachusetts to fabricate this prototype which will later be used as a pilot within a local brewery.