Hydrogen rich gas production from catalytic gasification of biomass Mohamed A. Hamad a, ** , Aly M. Radwan a, * , Dalia A. Heggo a , Tarek Moustafa b a National Research Center, Chemical Engineering & Pilot Plant Department, Cairo, Egypt b Faculty of Engineering, Chemical Engineering Department, Cairo University, Egypt article info Article history: Received 12 February 2015 Received in revised form 26 July 2015 Accepted 27 July 2015 Available online xxx Keywords: Gasification Biomass Hydrogen Catalysts abstract Production of hydrogen rich gas from gasification of biomass was studied at bench-scale using oxygen as the gasifying agent. A series of experiments were performed to investigate the effects of different operating parameters on the performance of the gasification process. These included the oxygen to fuel equivalence ratio (0.12e0.4), reaction temperature (700e850  C), reaction residence time (45e120 min), and catalyst type. The catalysts selected are marly clay, calcium hydroxide, dolomite, and cement kiln dust. Within the range of the experimental conditions tested, the results suggest that the best operating conditions for the gasification process are; temperature, 800  C, an oxygen to fuel ratio of 0.25, a reaction time of 90 min, and calcined cement kiln dust as a catalyst. The results have also demonstrated that the product gas from gasification of cotton stalks with calcium hydroxide has higher H 2 and CO concen- tration (45 and 33%). In addition gasification of cotton stalks with calcined cement kiln dust resulted in higher hydrogen and CO enrichment as well as higher overall gas yield (39vol%, 33vol%, and 1.5 m 3 /kg) compared to other agriculture residues of corn stalks and rice straw. © 2015 Published by Elsevier Ltd. 1. Introduction Gasification of biomass is an attractive alternative for the production of synthesis gas. A number of researchers have investigated the potential of biomass gasification for the pro- duction of synthesis gas. These studies can be categorized ac- cording the type of biomass used, type of reactor, the type and addition of catalyst, end products, and gasifying medium [1e12]. The types of biomass that have been tested include residue from municipal solid waste, saw dust, black liquor, and agricultural wastes [3,6]. Different types of reactors have been studied such as fixed-bed gasifiers, down-draft gasifiers, updraft gasifiers, Texaco gasifier, dual-bed gasifiers, and fluidized-bed gasifiers [1e5]. A wide variety of catalysts have been employed in gasifi- cation processes in literature such as dolomite, potassium min- eral, and nickel-based compounds [5e10]. One of the main challenges for gasification process is to apply a catalyst that can effectively improve the process, increase the gas production amount and quality at low cost. As for the gasifying medium, steam, air and oxygen have been used. In addition, the gasifica- tion process requires heat sources. Electrical energy, combustion heat of fossil fuel, and biomass have been reportedly used as a source of heat. Selection of the gasifier is dictated by specific features. A fixed-bed gasifier has been selected for this study due to its simplicity and relatively high hydrogen content in the gaseous product. The designed reactor is constructed from swa- gelock tubes and fittings to facilitate the assembling procedures. The effects of operating conditions such as temperature, resi- dence time, oxygen/biomass equivalence ratio, type of catalysts, and type of biomass on the performance of the gasification sys- tem have been investigated. The study focused on gasification of cotton stalks and determination of the optimum operating con- ditions. A special attention was devoted to the selection of effective catalyst with low cost. 2. Materials and methods 2.1. Biomass samples Cotton stalks, corn stalks, and rice straw were obtained from a farm in Sharkia Governorate, Egypt. Cotton stalks were used as a model biomass sample for the gasification experiments. They were screened to minimize particle size distribution effects. The mean * Corresponding author. National Research Center, Chemical Engineering and Pilot Plant Department, Tahrier St., Cairo, Egypt. ** Corresponding author. National Research Center, Chemical Engineering and Pilot Plant Department, Tahrier St., Cairo, Egypt. E-mail addresses: hamadnrc@hotmail.com (M.A. Hamad), radwnnrc@hotmail. com (A.M. Radwan). Contents lists available at ScienceDirect Renewable Energy journal homepage: www.elsevier.com/locate/renene http://dx.doi.org/10.1016/j.renene.2015.07.082 0960-1481/© 2015 Published by Elsevier Ltd. Renewable Energy 85 (2016) 1290e1300