Pyrolysis
is a viable option for the production of renewable energy
and agricultural resources from diverted organic waste streams. This
high temperature thermochemical process yields material with beneficial
reuses, including bio-oil and biochar. Gaseous forms of carbon (C)
and nitrogen (N) are also emitted during pyrolysis. The effluent mass
emission rates from pyrolysis are not well characterized, thus limiting
proper evaluation of the environmental benefits or costs of pyrolysis
products. We present the first comprehensive suite of C and N mass
emission rate measurements of a biomass pyrolysis process that uses
chicken manure as the feedstock to produce biochar and bio-oil. Two
chicken manure fast pyrolysis experiments were conducted at controlled
temperature ranges of 450–485 °C and 550–585 °C.
Mass emission rates of nitrous oxide (N<sub>2</sub>O), nitric oxide
(NO), carbon monoxide (CO), carbon dioxide (CO<sub>2</sub>), methane
(CH<sub>4</sub>), and ammonia (NH<sub>3</sub>) were measured using
trace gas analyzers. Based on the system mass balance, 23–25%
of the total mass of the manure feedstock was emitted as gas, while
52–55% and 23% were converted to bio-oil and biochar, respectively.
CO<sub>2</sub> and NH<sub>3</sub> were the dominant gaseous species
by mass, accounting for 58–65% of total C mass emitted and
99% of total reactive N mass emitted, respectively. Temperature variations
within the two set of temperature ranges had a perfunctory effect
on bio-oil production and gaseous emissions, but the higher temperature
range process produced more bio-oil and slightly less emissions. However,
a larger effect on the relative amounts of CO and CO<sub>2</sub> produced
were observed between the different temperature regimes. These results
have important implications for greenhouse gas and reactive N life
cycle assessments of biochar and bio-oil
