Fuel Ethanol Special Adsorbent Thermodynamic Study

The sources of energy is the driving power of existent of the nation and societies, if we see from a long term, the energy sources of China is insufficient. For this reason, the international community has followed to search and study the renewable energy, the fuel ethanol is a kind of renewable energy, which can be used to the additive of automobile fuel, and replace to the part of the mineral fuel, and reduce the pollution at the same time, and has been paid more attention widespread. In the United States and Brazil of etc. fuel ethanol has already got a popularization of the first step, so our country also started to realize the importance and have already started to carry the development of fuel ethanol.However the biggest energy waste of producing the fuel ethanol is the separation of ethanol and water currently, because when the consistency of ethanol(quantity) get to 95.57%, ethanol and water exist a common boiling point(78.15℃).For this, on the industry, people can adopt the common boiling point rectify, extraction rectify with salt, the method of membrane separation...etc. but the energy waste of all these methods is high, however the adsorption methods of biomass get a lower energy waste than other methods, adsorbing water with selectivity, this method is used in many corporations of different regions in recent years. Now we can only see some single materials to research the adsorption, such as corn starch and the wheat powder...etc. The components of the fuel ethanol special adsorbent did not appear in newspaper at nation or abroad.Experimental materials is the fuel ethanol special adsorbent of the center of biology chemistry engineering of Zhengzhou university and other biologic materials(sweet potato), this experiment adopted the inverse gas chromatography method, filled the GC column with special adsorbent, by calculating the interrelated GC thermodynamics parameters, for example, retention value of GC, adsorption heat, adsorption free energy of etc, and researched some influences (granularity temperature) of five different granularities (-80, 80-100, 100-120, 120-140, 140-mesh) of the fuel ethanol special adsorbents, at the base of that, experiment also studied the dehydration capability of sweet potato (80- 100 100- 120mesh), and drew conclusions: the lower temperature, the greater adsorption for water within the scope of 70-150℃; the smaller granularities, the higher adsorption within the scope of -80-140-mesh. The adsorption heat of the fuel ethanol special adsorbent for ethanol on five granularities is closed to each other, about -4.45(kJ·mol^-1); but for water, the adsorption heat exist some differences on five granularities, from -37.4(kJ·mol^-1) of 80mesh went up to -51.63(kJ·mol^-1) of 140-mesh. The adsorption heat of sweet potato for ethanol is also closed to each other, about -3.37(kJ·mol^-1); For water, because of only just two granularities, we can not analyze the influence of the granularities, the adsorption heat for water is about -48.47(kJ·mol^-1). So, the adsorption capability of the sweet potato for water is also very strong, this can provide some data references for optimizing the special adsorbent.