Journal of Analytical and Applied Pyrolysis 88 (2010) 30–38 Contents lists available at ScienceDirect Journal of Analytical and Applied Pyrolysis journal homepage: www.elsevier.com/locate/jaap Production of fuel from the catalytic cracking of pyrolyzed poultry DAF skimmings R. Hilten ∗ , R. Speir, J. Kastner, K.C. Das Department of Biological and Agricultural Engineering, Driftmier Engineering Center, University of Georgia, 597 D.W. Brooks Dr., Athens, GA 30602, United States article info Article history: Received 25 September 2009 Accepted 12 February 2010 Available online 20 February 2010 Keywords: Dissolved air flotation DAF Catalytic cracking Biofuel Pyrolysis Green diesel abstract A two-step thermochemical process, pyrolysis followed by catalytic cracking, was used to produce liquid fuels from poultry dissolved air flotation (DAF) skimmings, a waste material generated during poultry processing. Raw DAF-derived solids were dried and subjected to pyrolysis at 400, 500, 600 or 700 ◦ C to thermally crack the material into three physical phases; a gas, solid, and liquid. The liquid phase, DAF bio- oil, was further processed in an attempt to produce a liquid fuel capable of powering a diesel engine. After catalytic processing and collection, the DAF bio-oil exhibited a higher heating value (HHV) of 36 MJ kg -1 , which is less than the reported HHV of diesel (45.7 MJ kg -1 ), similar to biodiesel (36–40 MJ kg -1 ), but much higher than the HHV of bio-oil produced from the bioconversion of woody biomass (20 MJ kg -1 ). DAF bio- oil analysis generated measurements of HHV (MJ kg -1 ), cloud point ( ◦ C), viscosity (mm 2 s -1 at 40 ◦ C), and water content (%) revealed values of 36, 61.7, 37.8, and 4.72, respectively. After catalytic cracking, HHV increased to 40.2 MJ kg -1 , cloud point decreased to -2.7 ◦ C, viscosity decreased to 1.6 mm 2 s -1 , and water content decreased to 1.9% making it comparable to conventional fuels. The upgraded DAF bio-oil could be utilized as a fuel for direct combustion in industrial boilers for steam generating, blended with petroleum fuels as an additive, or used directly as diesel transportation fuel. © 2010 Elsevier B.V. All rights reserved. 1. Introduction Dissolved air flotation (DAF) is often used in the meat process- ing industry (poultry, swine, and bovine) to clarify wastewater by suspending and removing solids and oils. The byproduct of this pro- cess is a sludge with high moisture content (∼70%) that consists primarily of fats and proteins. After the removal of organic mate- rial using DAF, wastewater can then be treated in conventional wastewater treatment systems. As an alternative, Sena et al. [1] showed that DAF processing followed by an advanced oxidation process could effectively generate an effluent with organic loads acceptable for discharge. However, the issue of what to do with DAF solid waste still remains. Much of the DAF waste is land-filled, land-applied as fertilizer or rendered for animal feed. All of these disposal methods present their own problems such as transporta- tion and materials handling costs. In addition, high water content in DAF also poses a problem in rendering applications where addi- tional fees for dewatering can be incurred. According to Render Magazine’s 2006 Market Report, 4.3 mil tonnes of fat and grease were generated in the U.S. from the animal slaughter industry in 2006 [2]. The USDA publication, “Poultry – Production and Value ∗ Corresponding author at: Bioconversion and Carbon Cycling Program, Driftmier Engineering Center, United States. Tel.: +1 706 542 6681; fax: +1 706 542 8806. E-mail address: rog@uga.edu (R. Hilten). 2008 Summary” [3], states that 8.9 bil broiler birds were produced in the U.S. in 2008. Based on an estimate of 34 g of DAF skimmings generated per bird [4], 303,000 tonnes of wet DAF was generated in 2008 from broiler production. As an alternative to disposal or rendering, this material could be converted into a liquid transporta- tion fuel to help eliminate any disposal problems and would also serve as a value-added, marketable product derived from a waste stream. Thermochemical approaches are often used to generate value- added products including liquid and gaseous fuels and activated carbons from a wide range of waste materials including fats and grease [5–8], wood [9–11], seed/nut waste [12–15], and agricul- tural residues [16,17]. Pyrolysis and catalytic cracking are two commonly utilized thermochemical conversion techniques. Each process generates products in three physical phases; a solid, liq- uid and gas. The solid phase remaining after pyrolysis contains most of the minerals, or ash, that if left in the material could pose problems in fuel applications. The removal of ash is partic- ularly important in DAF upgrading due to relatively high levels (2%) that are present as a result of the use of polymers of acry- lamide and ferric chloride which are used as flocculating agents [18]. The liquid phase evolved during pyrolysis and catalytic crack- ing can, when condensed, be used as a liquid fuel. Also evolved during thermal process, permanent gases may include CO, CO 2 ,H 2 , and CH 4 along with many others including C 2 -C 6 gases in small concentrations. 0165-2370/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.jaap.2010.02.007