Removal of tar component over cracking catalysts from high temperature fuel gas Binlin Dou a, * , Weiguo Pan a , Jianxing Ren a , Bingbing Chen a , Jungho Hwang b , Tae-U Yu c a Department of Energy and Environment Engineering, Shanghai University of Electric Power, Shanghai, PR China b Department of Mechanical Engineering, Yonsei University, Seoul, Republic of Korea c Korea Institute of Industrial Technology, Chunan, Republic of Korea Received 1 November 2006; received in revised form 12 June 2007; accepted 31 January 2008 Available online 14 March 2008 Abstract Five catalysts were evaluated for removal of tar components in high temperature fuel gas cleaning. 1-Methylnaphthalene was chosen as a model of the tar components. The NiMo catalyst having the highest surface area exhibited the highest activity of tar removal among the five catalysts. The effects of reaction temperature and space velocity on tar removal were studied in the range of 250–650 °C and 3000–9000 h 1 , respectively. A lumped kinetic model was developed to describe the removal process. A sequential method to estimate the rate constants in the lumped kinetic model was adopted, which greatly simplifies the data treatments. Kinetic constants and activa- tion energies were determined by a nonlinear regression program. The results showed that the predicted yields were very close to the experimental ones. Ó 2008 Elsevier Ltd. All rights reserved. Keywords: Tar removal; Catalyst; Kinetic model 1. Introduction The removal of tar components is one of the most cru- cial problems in developing biomass energy and the clean- est advanced power technology including high temperature molten carbonate fuel cells (MCFC) and integrated coal gasification combined cycles (IGCC). The tars are not readily removed from the fuel gas in these processes by conventional means and, as a consequence, often result in plugged filters or fouled fuel cells, turbines, or sorbents [1]. Several types of catalysts such as HZSM-5, silica–alu- mina and nickel based catalysts have been found to be very effective catalysts for cracking tars generated from fuel gases [2–7]. Kinetic studies on catalytic cracking reactions have been conducted in fluidized catalytic cracking (FCC) units. Because of the thousands of compounds involved, the system is simplified as a group or lumping the com- pounds into a group according to their boiling points and/or their molecular characteristics. A 3 lump kinetic model was first developed by Weekman [8], comprised of unconverted feed, gasoline and gas plus coke as the 3 lumps. Since these studies, more complex kinetic models for the FCC process including 4 lump [9,10], 5 lump [11], 6 lump [12] and 10 lump [13] models have been developed. One of the major difficulties in the development of a kinetic model is the description of the rapid deactivation of the catalyst as a result of coke formation [14]. These polyaro- matic species block active sites. Coke deposition has been proposed as one of several reasons responsible for the rapid deactivation of catalysts [7]. So, it is of significance to understand the removal kinetics, especially the mechanism of tar removal and coke formation. In the present work, we evaluate five catalysts for removal of tar components in high temperature fuel gas cleaning and adopt a new kinetic method for removal of tars with which method the coke formation can be predicted separately. This sequential method decreases the number of simultaneously estimated 0196-8904/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.enconman.2008.01.027 * Corresponding author. Tel.: +86 21 65497221. E-mail addresses: doubinlin@hotmail.com (B. Dou). www.elsevier.com/locate/enconman Available online at www.sciencedirect.com Energy Conversion and Management 49 (2008) 2247–2253