Background/Objectives
Pyrolysis is the heating of biomass in the absence of oxygen. Since there is no combustion, pyrolysis of biomass generates biochar, a charcoal-like residue, and gas. Most of the gas is condensed into bio-oil; the remaining gas is considered “syngas”.
Biochar has long been used to improve productivity of agricultural soils, especially in the humid tropics. Because biochar persists in soil for centuries to millennia, its use as a soil additive represents a method to sequester carbon drawn from the atmosphere by some form of biomass (e.g. hay, corn, other crops, trees). [Note: Land management is the second largest contributor to carbon dioxide emissions on earth.] Additionally, on-going research seems to suggest biochar may also provide benefits such as enhanced soil water-holding capacity and nutrient retention.
The proportion of products generated during pyrolysis depends on several factors including biomass composition. Pyrolysis of crop residuals results in generation of large surpluses of bio-oil and syngas, which can be used to generate renewable energy, along with biochar. Due to the high moisture content of dairy manure, on-the-other-hand, pyrolysis of dairy manure primarily results in reduction of moisture content (approximately 96%), along with biochar. Since manure is produced in abundance, excess manure (i.e., manure not employed for higher-value end uses) may exceed the nutrient limits set for nearby farm fields. As such, dairy farmers are often required to transport manure to distant farm fields. Reducing the moisture content of manure should result in significantly reduced or avoided transportation requirements.
Pyrolysis has been standard practice for the conversion of woody biomass to charcoal for millennia; and is proven technology for waste management at large scale and for power generation at multiple scales. On-farm pyrolysis of dairy manure is an emerging practice for some of the reasons that follow:
- Dairy manure is not fully valued as an energy asset;
- The value proposition for pyrolyzing dairy manure has not been demonstrated; and
- Biochar and biochar-based fertilizers are not yet sufficiently considered tradable
The objectives of the project are three-fold: 1) to assess the economic viability and commercialization potential of using pyrolysis to treat excess dairy manure in NYS; 2) if deemed economically viable and having commercialization potential, to demonstrate pyrolysis of dairy manure and potentially other crop residuals; 3) to disseminate project results, including measurement and verification (M&V) data supplied by the M&V contractor, to key NYS agriculture stakeholders with the goal of accelerating the adoption and market penetration of the technology throughout NYS.
The project built on pilot-scale production and detailed characterization of biochar made from dairy manure in NY State, funded by The Innovation Center for US Dairy described here.