Thermodynamic Analysis of Ethanol Dry Reforming: Effect of Combined Parameters

The prospect of ethanol dry reforming process to utilize CO2 for conversion to hydrogen, syngas, and carbon nanofilaments using abundantly available biofuel—ethanol, and widely available environmental pollutant CO2 is very enthusiastic. A thermodynamic analysis of ethanol CO2 reforming process is done using Gibbs free energy minimization methodology within the temperature range 300–900°C, 1–10 bar pressure, and CO2 to carbon (in ethanol) ratio (CCER) 1–5. The effect of individual as well as combined effect of process parameters such as temperature, pressure, and CCER was determined on the product distribution. Optimum process conditions for maximising desired products and minimizing undesired products for applications such as gas to liquids (GTL) via fischer tropsch synthesis, syngas generation for Solid oxide fuel cells, and carbon nanofilament manufacture were found in this study. 1. Introduction CO2 reforming (also known as dry reforming) is a useful way to utilize CO2 to transform it into valuable species such as hydrogen, syngas, and carbon (nanofilaments). CO2 reforming is analogous to steam reforming which has been widely used to produce hydrogen for different applications. Although dry reforming (DR) is a known process in the chemical literature, catalyst deactivation due to carbon formation was its major drawback. However, with increase in CO2 pollution awareness, researchers have started fresh studies in dry reforming to utilize (and thus sequester) CO2. This move has come with a bonus: carbon nanofilament formation was reported in some experimental studies of dry reforming. Dry reforming of natural gas was a major research area. Many research studies on dry reforming of methane have been reported [1–6]. Dry reforming of butanol [7], glycerol [8], and coke oven gas [9] has also been studied by some researchers. The popularity of biofuels and use of biomass has brought an alternative to natural gas. Ethanol is cheaply available in many countries. It is easily manufactured by biomass fermentation can be stored and transported safely. Hence, ethanol is a potential fuel that can be easily used in dry reforming processes. Dry reforming of ethanol has been studied by some researchers: De Oliveira-Vigier et al. [10] have experimentally studied the dry reforming of ethanol using a recyclable and long-lasting SS 316 catalyst and have obtained a hydrogen yield that is 98% of the theoretical value. Blanchard et al. [11] have experimentally studied the ethanol dry reforming using a carbon steel catalyst to produce syngas and nanocarbons. Bellido et al.