4-014 (P) The Joint International Conference on “Sustainable Energy and Environment (SEE)” 1-3 December 2004, Hua Hin, Thailand 476 1. INTRODUCTION In recent year, a lot of plastic wastes are accumulated because most plastics are not degraded. A common method to reduce plastic wastes is recycling. There are four types of recycling. Primary recycling is the reprocessing of scrap plastic. Secondary recycling is the remolding of plastic waste. Tertiary recycling is the conversion of plastic waste to petrochemical feedstock or fuel oil. The last one is quaternary recycling which produces energy from plastic wastes. The primary and the secondary recycling have limits in use because products from these recycling have low mechanical properties. The quaternary recycling produces air pollution from combustion reaction. Therefore, tertiary recycling is an appropriate method to reduce plastic waste. Pyrolysis reaction is a type of tertiary recycling. It is a thermal decomposition of organic materials in the absence of air [1]. Plastic waste is converted to fuel oil or feedstock. There are many researchers who study pyrolysis of plastic waste in different ways. Kaminsky and Kim [2] studied pyrolysis of mixed plastic in a lab scale fluidized bed reactor. They determined the composition of products and compared with technical process. The concentration of chloro-organic was lower in technical process due to long residence time. Wong and Broadbelt [3] studied pyrolysis of polypropylene and polystyrene binary mixture. The overall conversion of binary mixture was higher than the average conversion of pure case. Ciliz et.al. [4] pyrolyzed virgin and waste of polypropylene and polypropylene, polyethylene and polystyrene mixtures by thermal gravimetric technique for kinetic study. The results showed impurities in waste plastic affected liquid product. Pyrolysis of plastics has been developed to commercial scale. However, pyrolysis process has a problem if polyvinyl chloride (PVC) exists in plastic waste. Pyrolysis of PVC causes corrosion problem from the hydrogen chloride produced. Many researchers have studied different methods of hydrogen chloride removal in pyrolysis of plastic waste. Yoshioka et.al. [5] decomposed PVC by oxidative degradation NaOH solution. The PVC was converted to carboxylic acid. Some metal oxide can be used in hydrogen chloride removal. It was changed to metal chloride form. Bhaskar et.al. [6] used calcium carbonate carbon composite in hydrogen chloride adsorbent. This adsorbent showed high efficiency, it gave chlorine free liquid product for consecutive six batch processes. Zhou et.al. [7,8] studied Corresponding author: fengapd@nontri.ku.ac.th catalytic dechlorination using Al-Mg and Al-Zn composite oxide catalyst. However, these metal oxides have some cost when it is scaled up to a commercial plant. An alternative method of hydrogen chloride removal in low operating cost is investigated in this study. The non-value substance such as cattle manure can be used in hydrogen chloride removal. While the manure is heating, ammonia gas is produced and reacted with hydrogen chloride. Ammonium chloride is formed. This research is aimed to study copyrolysis of PVC with cattle manure to remove hydrogen chloride. 2. EXPERIMENT 2.1 Pyrolysis reaction Pyrolysis reaction was carried out in a semi-batch reactor. The 700 ml cylindrical stainless steel reactor was placed in an electrical furnace. The process diagram is shown in Fig 1. Polyvinyl chloride (PVC) was obtained from VinyThai Public Company, Thailand. It was mixed with cattle manure at various ratios and loaded in the reactor. The reaction was run in two steps. First step, the reactor was heated to 250 o C for dechlorination reaction and remained at this temperature for 30 min. After that the reactor was heated to pyrolysis temperature. Liquid was condensed by a condenser and collected in a flask. The gas product passed through sodium hydroxide solution. The remaining hydrogen chloride was absorbed and the gas products were collected in a gas sampling bag. 2.2 Analysis of product In pyrolysis reaction, there are three types of products; solid, liquid and gas. The proximate analysis of solid product was followed ASTM D3172-89. The heating value of liquid product was determined by bomb calorimeter (model PAR 1261) and gas product was analyzed by gas chromatograph (model varian CP3800). The amount of sodium hydroxide remained in the solution after the reaction was analyzed to determine hydrogen chloride removal efficiency. In Situ Removal of HCl in Copyrolysis Process of Fertilizer / Cattle Manure and Polyvinyl Chloride Chanatip Samart and Apinya Duangchan * Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok, Thailand Abstract: An alternative method of hydrogen chloride removal in PVC pyrolysis used cattle manure and fertilizer. Preliminary study of thermal decomposition of PVC, cattle manure and fertilizer showed decomposition at the range 230-320 o C. Releasing of HCl from PVC degradation and of ammonia from cattle manure and fertilizer degradation happened in this temperature. The ammonia reacts with HCl and becomes ammonium chloride. Copyrolysis of PVC and cattle manure or fertilizer was studied in a semi-batch reactor under nitrogen atmosphere. HCl was absorbed in sodium hydroxide and the removal efficiency was determined by back titration of the remaining sodium hydroxide. The HCl removal efficiencies increased from 40% to 80-85% when the amounts of cattle manure and fertilizer was increased from 1 to 6 times of PVC at 450 o C and the removal was nearly complete at 600 o C. Solid and liquid yield increased when the amount of manure fertilizer was increased. The main gas products were propane and carbon monoxide. The pH of the solid carbon was 5-6 for copyrolysis of PVC with fertilizer and 7 with cattle manure. Fixed carbon of the solid product was less than 20%. Keywords: HCl Removal, PVC, Copyrolysis, Cattle Manure, Manure Fertilizer.