Study On Characteristics Of Steam Gasification Of Fruit Waste And Enhanced Hydrogen Production By Ni/Kaolin

At present,China has begun to implement a waste classification system,which provides powerful conditions for the energy and resource utilization of waste.Gasification technology is used to treat kitchen waste,which can not only use the water in the kitchen waste as a gasification agent to participate in the reaction,but also produce hydrogen.Kitchen waste,such as fruit waste,has been widely concerned because of its great gasification reaction performance,but its hydrogen production capacity and change rules are not yet clear during gasification reaction.This paper carries out research on the above issues,which has an important guiding role in promoting the energy utilization of fruit waste.In this paper,orange peel is used as a representative component of fruit waste.The hydrogen production performance of steam gasification of orange peel,waste paper,PET,cotton and pine wood were studied in a fixed-bed gasification reaction system.The effect of reaction conditions on the characteristics of orange peel gasification was investigated,and the synergistic effect of water-carbon ratio（S/C）and reaction temperature on gas production of orange peel gasification was analyzed.Kaolin is used as a carrier to prepare a highly active catalyst.Investigated the relationship between the physicochemical properties of the catalyst and its catalytic activity.The effect of Ni loading on the activity of Ni/kaolin catalyst was investigated.The main conclusions obtained from this research are as follows:（1）This research has shown that orange peel has excellent hydrogen production capacity by gasification.Under the same reaction conditions（reaction temperature is1073 K,S/C=14.4）,the carbon conversion efficiency and hydrogen concentration of the orange peel gasification reaction were 61.22%and 56.36%,which were higher than that of waste paper,PET,cotton cloth,and pine wood chips.（2）The effect of key gasification parameters on the hydrogen production performance of orange peel gasification was clarified.The increase of S/C is beneficial to improve the carbon conversion efficiency,H₂concentration and yield,but too much steam will cause the decrease of carbon conversion efficiency;The changing trend of H₂concentration and yield with the reaction temperature is related to S/C.When S/C=0,because the carbon conversion efficiency is low,the temperature can effectively promote the cracking of tar and improve the carbon conversion efficiency,so it contributes to the increase of H₂concentration and yield;When S/C=14.4 and the temperature is higher than 1073 K,the promoting effect of temperature on tar cracking is not obvious,but the reverse water gas reaction was obviously promoted,resulting in a decrease in H₂yield.（3）The characteristic of Ni/kaolin enhanced hydrogen production from fruit waste steam gasification was obtained and revealed the reason for the high catalytic activity of Ni/Kaolin.The catalytic activity of Ni/kaolin catalysts is higher than that of Ni/Si O₂,Ni/γ-Al₂O₃and Ni/（Si O₂+Al₂O₃）catalysts,because Ni generates uniform tetrahedral clusters on the surface of kaolin,which can fully expose Ni（111）on the surface of kaolin,and Ni（111）can effectively break the C-C bond and C-H bond of tar,thus effectively promoted hydrocarbon reforming reaction and tar cracking reaction,and improved carbon conversion efficiency and H₂yield.The optimal loading of Ni/kaolin is 14%.When the Ni loading is 14%,during the orange peel gasification reaction,the carbon conversion efficiency reached 88.62%,and the generated H₂concentration and yield reach 68.37%and 409.43 ml/g,respectively.H₂yield reached 91.62%of theoretical maximum hydrogen yield。...