The Basic Studv Of Aluminum Recvcle System Based On Aluminum-water Reaction And Carbo-thermal Reduction

Energy crisis and environmental pollution are two main problems human faced,so it's very important to research new type of energy and hydrogen is a good option for its high calorific value,friendly to the environment and renewability.Aluminum-water reaction can produce hydrogen with much heat released,and can be used in various occasions.Improving the reaction efficiency has great significance to the aluminum energy system based on aluminum-water reaction and carbothermol-chlorination reduction reaction.The aluminum-based energy hydrogen production system has advantages in reducing energy consumption and environment protection,which is of great significance for the development of resource-saving and environment-friendly society.In this paper,the dynamic characteristics of aluminum water reaction and the promotion effect of magnesium lithium on the reaction were studied first.The experiments were conducted with THERMO CAHN's Thermax500 pressurized thermogravimetric analyzer.The Al content was settled at 85%,and the Mg and Al contents were adjusted from 0%to 15%.The addition of Li and Mg into A1 resulted in good hydrolysis performance,and the ratio of the reacted A1 to the total Al was over 50%and even reached up to 89%.The reaction process showed an obvious three-stage feature,and the three stages primarily corresponded to the reactions of Li,Mg,and Al.The products of hydrolysis in our tests were LiAlO₂,Li₂Al₄O₇,AL₂O₃,and MgO.The three different promotion mechanisms,local high temperature,reaction with oxidation production and physical collisions,of Li and Mg on the Al-H₂O reaction were also analyzedCarbo-thermal reduction aluminum is regarded as the future aluminum production method for its low energy consumption and low pollution.A thermodynamics analysis is performed,taking the Al-C two-step model as the objective.High temperature is beneficial to the reaction efficiency,but harmful to the exergy efficiency of the first reaction.The second reaction presents an opposite pattern.An optimal reaction temperature window exists for the AlCl mediated carbon reduction method.Heat recovery is significantly important in enhancing both exergy efficiency and energy consumption in actual processes.Energy consumption is reduced from 11,335 kW-h/t?Al?to 8063 kW·h/t?Al?when an ideal heat recovery is performed.Compared with electrolytic aluminum,carbothermol-chlorination reduction presents a significantly better performance in some condition.Moreover,67%of the exergy efficiency of the carbothermol-chlorination reduction is greater by 1.7 times than that of the electrolytic aluminum.The designed a aluminum recycled system is based on aluminum-water production and carbothermol-chlorination reduction,which use the alumina produced by aluminum-water reaction as main material of carbothermol-chlorination reduction to make a realization of recycling.The research made a life cycle assessment on the energy system.It's found that it can reduce 17.9%energy consumption,34.3%greenhouse gas emission and much of human toxicity potential.The results showed that CCRA has a good potential in environment protection and energy saving.