Effect of the type of gasifying agent on gas composition in a bubbling ﬂuidized bed reactor Emir Aydar * , Serhat Gul 1 , Namık Unlu 1 , Fehmi Akgun 2 , Haydar Livatyali 3 Q5 TUBITAK Marmara Research Center Gebze Campus Energy Institute, 41470 Kocaeli, Turkey Q1 article info Article history: Received 15 January 2013 Accepted 29 April 2013 Keywords: Coal gasiﬁcation Bubbling ﬂuidized bed Synthesis raw gas Steam Equivalence ratio abstract It is commonly accepted that gasiﬁcation of coal has a high potential for a more sustainable and clean way of coal utilization. In recent years, research and development in coal gasiﬁcation areas are mainly focused on the synthetic raw gas production, raw gas cleaning and, utilization of synthesis gas for different areas such as electricity, liquid fuels and chemicals productions within the concept of poly- generation applications. The most important parameter in the design phase of the gasiﬁcation process is the quality of the synthetic raw gas that depends on various parameters such as gasiﬁer reactor itself, type of gasiﬁcation agent and operational conditions. In this work, coal gasiﬁcation has been investigated in a laboratory scale atmospheric pressure bubbling ﬂuidized bed reactor, with a focus on the inﬂuence of the gasiﬁcation agents on the gas composition in the synthesis raw gas. Several tests were performed at continuous coal feeding of several kg/h. Gas quality (contents in H 2 , CO, CO 2 , CH 4 ,O 2 ) was analyzed by using online gas analyzer through experiments. Coal was crushed to a size below 1 mm. It was found that the gas produced through experiments had a maximum energy content of 5.28 MJ/Nm 3 at a bed tem- perature of approximately 800  C, with the equivalence ratio at 0.23 based on air as a gasiﬁcation agent for the coal feedstock. Furthermore, with the addition of steam, the yield of hydrogen increases in the synthesis gas with respect to the water–gas shift reaction. It was also found that the gas produced through experiments had a maximum energy content of 9.21 MJ/Nm 3 at a bed temperature range of approximately 800–950  C, with the equivalence ratio at 0.21 based on steam and oxygen mixtures as gasiﬁcation agents for the coal feedstock. The inﬂuence of gasiﬁcation agents, operational conditions of gasiﬁer, etc. on the quality of synthetic raw gas, gas production efﬁciency of gasiﬁer and coal conversion ratio are discussed in details. Ó Energy Institute. 1. Introduction The oil crisis and global environmental problems have become critical challenge worldwide; therefore, more and more attention has been paid to the clean coal technologies, among which the coal gasiﬁcation is one of the critical ones for efﬁcient utilization of coal. Compared to the coal combustion, there is a lower reaction rate in coal gasiﬁcation process. Coal gasiﬁcation is becoming an attractive alternative for power generation since it offers higher efﬁciency and improved environmental performance than conventional pulverized fuel technology [1]. Various types of gasiﬁers such as moving bed, entrained ﬂow, and ﬂuidized beds have been employed by industry, but intensive research activities for technology development and improvement are still ongoing. Fluidized bed reactors are much more suitable for low rank coal having mostly high ash, high sulfur and high moisture. Therefore, ﬂuidized bed gasiﬁers have the potential advantage that low rank coals can be processed more efﬁciently than in conventional pulverized coal boilers. The higher efﬁciency that coal gasiﬁcation offers could be used as a strategy for carbon abatement in the future. A potential disadvantage of * Corresponding author. Tel.: þ90 262 677 2820; fax: þ90 262 641 2309. Q2 E-mail addresses: emir.aydar@mam.gov.tr (E. Aydar), serhat.gul@mam.gov.tr (S. Gul), namik.unlu@mam.gov.tr (N. Unlu), fehmi.akgun@mam.gov.tr (F. Akgun), haydar.livatyali@mam.gov.tr (H. Livatyali). 1 Tel.: þ90 262 677 2791; fax: þ90 262 641 2309. Q3 2 Tel.: þ90 262 677 2771; fax: þ90 262 641 2309. 3 Tel.: þ90 262 677 2824; fax: þ90 262 641 2309. Contents lists available at ScienceDirect Journal of the Energy Institute journal homepage: http://www.journals.elsevier.com/journal-of-the-energy- institute http://dx.doi.org/10.1016/j.joei.2014.02.004 1743-9671/Ó Energy Institute. Journal of the Energy Institute xxx (2014) 1–8 JOEI5_proof ■ 3 March 2014 ■ 1/8 Please cite this article in press as: E. Aydar, et al., Effect of the type of gasifying agent on gas composition in a bubbling ﬂuidized bed reactor, Journal of the Energy Institute (2014), http://dx.doi.org/10.1016/j.joei.2014.02.004 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54