The effect of recycled plastics and cooking oil on coke quality Liséte Celina Lange ⇑ , Alison Frederico Medeiros Ferreira Federal University of Minas Gerais (UFMG), School of Engineering, Pampulha Campus, Department of Sanitary and Environmental Engineering, Block 2, Room 4628, Av. Antônio Carlos, 6627, Pampulha, Belo Horizonte, Minas Gerais CEP: 31.270-901, Brazil article info Article history: Received 7 July 2015 Revised 13 April 2016 Accepted 31 August 2016 Available online xxxx Keywords: Plastics Vegetable oil waste Coke Energy recycling Box test Hearth heating furnace abstract This study assessed the effects of adding plastics and waste vegetable oil on the quality of coke in the coking process, on a pilot scale. A typical composition of the main plastics found in municipal solid waste was prepared using 33% HDPE, 5% LDPE, 10% PP, 21% PET, 24.8% PS, 5.2% PVC, 1% cellulose and also a 0.5% waste vegetable oil was added. The wastes were added to the coal blends in the proportions of 1%, 2% and 3% for plastics and 0.5% for vegetable oil. Two types of experiments were performed. The first was carried out in a hearth heating furnace (HHF) at temperatures of up to 900 °C for a 7 h period. The second was a box test, which consists of heating coal blends in 18 L cans using a pilot coking oven, for approximately 20 h at temperatures between 1050 and 1100 °C. The quality parameters used for the assessment were the CSR (coke strength after reaction), CRI (coke reactivity index), ash, volatile matter and sulfur in order to identify the effect of plastic and vegetable oil on coke quality. Results for CSR in the HHF averaged 52.3%, and 56.63% in box test trials. The CRI results ranged from 26.6% to 35.7%. Among the different percentages of plastics used, 3% plastic blends provided the most stable CSR results. The industrial furnaces work at temperatures between 1100 and 1350 °C and time coking 21–24 h, compared to the test conditions achieved in the HHF and pilot furnace with box test. It was concluded that the results of CSR and CRI are consistent with the tests confirming the feasibility of using plastic in the steelmaking process. Ó 2016 Elsevier Ltd. All rights reserved. 1. Introduction The increasing consumption of resins and plastics in recent years has led to a large amount of plastic waste being generated. This has contributed to an increase in municipal solid waste (MSW), as plastics represent a considerable percentage of the waste produced. According to Plastics Europe (2014), 25.2 million tons of plastic waste were generated in Europe in 2012, of which 62.0% was recovered through recycling and energy recovering pro- cesses and 38.0% discarded. In Japan, 9.52 million tons of plastic waste were produced in 2011, with 4.65 million tons coming from urban waste and 4.86 million coming from industrial waste (PWMI, 2013). Estimates for Brazil indicate approximately 6.6 mil- lion tons of plastic waste were generated in 2010. Despite the large amount of existing resins, low-density polyethylene (LDPE), high- density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET) and polyvinyl chloride (PVC) account for 85% of plastic consumption in Brazil and around the world, and are therefore more common in MSW (ABRELPE, 2010). Among the materials in MSW, plastic has one of the largest energy potentials in terms of kcal/kg. Moreover, when evaluating energy potential by resin type, polyethylene displays the greatest value among plastics, a noteworthy property considering that polyethylene is the most abundant polymer in MSW in Brazil. The country with the highest percentage of energy recovery from MSW is Japan. According to PWMI (2013), their plastic recycling rate reaches 78%, corresponding to 7.44 million tons. Among the several recycling technologies at their disposal, electricity generat- ing incineration accounts for 34% of the plastic recycling rate and is the leading technique in Japan, followed by mechanical recycling (22%) and other processes (22%). These other technologies, which can be divided into chemical recycling and recycling of raw mate- rials, include blast furnaces, coke plants, gasification and liquefac- tion. In Brazil, mechanical recycling is the most utilized process and yields a recycling rate of 19.4% for plastic waste (ABRELPE, 2010). The major thermoplastics begin softening and melting between 70 and 170 °C, depending on the type of resin, purity of material and presence of additives. Thermal polymer degradation occurs when molecules are broken down by the depolymerization of plastics, which occurs between 200 and 500 °C(Kato et al., 2002). However, plastics decompose at a much lower temperature than coal. Coal begins its decomposition process at 450 °C. Therefore, adding plastics to coal helps reduce its softening temperature and is considered a positive effect (Diez et al., 2009). http://dx.doi.org/10.1016/j.wasman.2016.08.039 0956-053X/Ó 2016 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: lisete@desa.ufmg.br (L.C. Lange). Waste Management xxx (2016) xxx–xxx Contents lists available at ScienceDirect Waste Management journal homepage: www.elsevier.com/locate/wasman Please cite this article in press as: Lange, L.C., Ferreira, A.F.M. The effect of recycled plastics and cooking oil on coke quality. Waste Management (2016), http://dx.doi.org/10.1016/j.wasman.2016.08.039