title: Valorization of horse manure through catalytic supercritical water gasification.
abstract: The organic wastes such as lignocellulosic biomass, municipal solid waste, sewage sludge and livestock manure have attracted attention as alternative sources of energy. Cattle manure, a waste generated in surplus amounts from the feedlot, has always been a chief environmental concern. This study is focused on identifying the candidacy of horse manure as a next generation feedstock for biofuel production through supercritical water gasification. The horse manure was gasified in supercritical water to examine the effects of temperature (400-600°C), biomass-to-water ratio (1:5 and 1:10) and reaction time (15-45min) at a pressure range of 23-25MPa. The horse manure and resulting biochar were characterized through carbon-hydrogen-nitrogen-sulfur (CHNS), inductively coupled plasma-mass spectrometry (ICP-MS), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM). The effects of alkali catalysts such as NaOH, Na2CO3 and K2CO3 at variable concentrations (1-2wt%) were investigated to maximize the hydrogen yields. Supercritical water gasification of horse manure with 2wt% Na2CO3 at 600°C and 1:10 biomass-to-water ratio for 45min revealed maximum hydrogen yields (5.31mmol/g), total gas yields (20.8mmol/g) with greater carbon conversion efficiency (43.1%) and enhanced lower heating value of gas products (2920kJ/Nm(3)). The manure-derived biochars generated at temperatures higher than 500°C also demonstrated higher thermal stability (weight loss <34%) and larger carbon content (>70wt%) suggesting their application in enhancing soil fertility and carbon sequestration. The results propose that supercritical water gasification could be a proficient remediation technology for horse manure to generate hydrogen-rich gas products.
authors.affiliation: Department of Earth and Space Science and Engineering, Lassonde School of Engineering, York University, Ontario, Canada.
authors.forename: Sonil
authors.initials: S
authors.lastname: Nanda
authors.affiliation: Department of Chemical and Biological Engineering, University of Saskatchewan, Saskatchewan, Canada.
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Dalai
authors.affiliation: Institut de Combustion Aérothermique Réactivité et Environnement (ICARE), Centre National de la Recherche Scientifique (CNRS), Orléans, France.
authors.forename: Iskender
authors.initials: I
authors.lastname: Gökalp
authors.affiliation: Department of Earth and Space Science and Engineering, Lassonde School of Engineering, York University, Ontario, Canada. Electronic address: janusz.kozinski@lassonde.yorku.ca.
authors.forename: Janusz A
authors.initials: JA
authors.lastname: Kozinski
mesh_terms: D000818:Animals; D002244:Carbon; D002606:Charcoal; D006736:Horses; D006859:Hydrogen; D008372:Manure; D009584:Nitrogen; D011312:Pressure; D012722:Sewage; D013455:Sulfur; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*; D014867:Water
chemical_list: D008372:Manure; D012722:Sewage; C540010:biochar; D014867:Water; D002606:Charcoal; D013455:Sulfur; D002244:Carbon; D006859:Hydrogen; D009584:Nitrogen
keywords: Alkali catalyst; Biochar; Feed concentration; Horse manure; Reaction time; Supercritical water; Temperature