Fuels and chemicals from equine-waste-derived tail gas reactive pyrolysis oil: technoeconomic analysis, environmental and exergetic life cycle assessment

Authors: SORUNMU, YETUNDE - Drexel University; BILLEN, PIETER - Drexel University; Elkasabi, Yaseen; Mullen, Charles; MACKEN, NELSON - Swarthmore College; Boateng, Akwasi; SPATARI, SABRINA - Drexel University

Submitted to: ACS Sustainable Chemistry & Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/3/2017
Publication Date: 9/4/2017
Publication URL: https://handle.nal.usda.gov/10113/5808050
Citation: Sorunmu, Y., Billen, P., Elkasabi, Y.M., Mullen, C.A., Macken, N., Boateng, A.A., Spatari, S. 2017. Fuels and chemicals from equine-waste-derived tail gas reactive pyrolysis oil: technoeconomic analysis, environmental and exergetic life cycle assessment. ACS Sustainable Chemistry & Engineering. 5:8804-8814.

Interpretive Summary: Utilization of excess agricultural resources will bring profit to farmers if they are converted into useful chemicals. Various technologies for producing biofuels from these resources are possible, but they vary based upon their ability to alleviate environmental pollutants. Another important parameter is the overall cost of the process. The biofuel production process must also be financially feasible and, ideally, competitive with the price of fossil fuels. One type of biofuel comes from pyrolysis, which is the heating of biomass in the absence of oxygen. Pyrolysis produces a liquid oil product that is capable of becoming fuel, after specific refining processes. This paper assessed the ability for horse manure to be converted via pyrolysis into an oil in an environmentally and cost-effective manner. Profit from product sales was taken into consideration. The assessment also evaluated the production of gases known to affect environmental temperature increases. While typically the fuel selling price from this process was estimated to be significantly greater than that from fossil fuel, a significantly lower price closer to fossil fuel is possible when the market conditions are optimal. These conditions include significantly high selling prices for the coproducts (phenols). However, the effect of pyrolysis on environmental gases produced is less than that from fossil fuel.

Technical Abstract: Horse manure, whose improper disposal imposes considerable environmental costs, constitutes an apt feedstock for conversion to renewable fuels and chemicals when tail gas reactive pyrolysis (TGRP) is employed. TGRP is a modification of fast pyrolysis that recycles its non-condensable gases and produces a bio-oil low in oxygen concentration and rich in naphthalenes. Herein, we evaluate the co-production of phenol as a value-added renewable chemical alongside jet-range fuels within distributed TGRP systems using techno-economic analysis and life cycle assessment. We investigate the metrics global warming potential (GWP), cumulative exergy demand (CExD), and cost for the conversion of 200 dry metric tons per day of horse manure to bio-oil and its subsequent upgrade to hydrocarbon fuel and phenolic chemicals. Assigning credits for the offset of the co-products, the net GWP and CExD of TGRP jet fuel are 10 g of CO2 eq. and 0.4 MJ per passenger kilometer distance traveled, respectively. These values are considerably lower than the GWP and CExD of petroleum-based aviation fuel. The minimum fuel selling price of the TGRP jet fuel ($1.35-1.8 L-1) is estimated to be much greater than that of petroleum-based aviation fuel ($0.42 L-1) except under optimized fuel conversion and co-product market conditions ($0.53-$0.79 L-1) when including a market price for carbon.