Experiment And Simulation Of Thermochemical Hydrogen Production From Copper Chlorid

Hydrogen is a clean energy with broad application prospects.It can not only be used as a high-energy fuel and a raw material for the petrochemical industry,but also as a reducing agent in the metallurgical industry and a protective gas in the high-temperature processing of metals.Hydrogen production methods and efficiency have always been the focus of research.At present,industrial hydrogen production methods include fossil fuel hydrogen production technology,water splitting hydrogen production,and biomass hydrogen production.These technologies have high energy consumption,low efficiency,and are not environmentally friendly.Find a new way to produce hydrogen.In this paper,the two-step copper-chlorine thermochemical hydrogen production technology was studied from the perspectives of experimental research,thermodynamics,and microscopic kinetics.（1）This paper conducts a detailed study on the CuCl₂hydrolysis step in the Cu-Cl thermochemical cycle:systematically combing and calculating the thermodynamics of possible reactions in the hydrolysis reaction;characterizing the hydrolyzate by XRD analysis,it is proved that at 400℃Copper oxide and other by-products exist at the same time,and the reaction is completely carried out at 600℃.The effects of the particle size of copper chloride powder,carrier gas flow rate and steam molar ratio on the hydrolysis yield were studied.The results showed that the hydrolysis yield of ball milling for 6 hours was the highest,the yield showed an increasing trend when the carrier gas flow rate increased from 65 ml/min to 95 ml/min.However,when the carrier gas flow rate exceeds 95 ml/min,the contact time between the reactants is shortened,and the water molecules in the steam cannot fully react with CuCl₂,resulting in a decrease in yield;Meanwhile,the higher the ratio of H₂O/CuCl₂,the higher the conversion rate.（2）Using cuprous chloride and hydrochloric acid as raw materials,the electrolysis reaction of Cu-Cl thermochemical cycle was studied.The gas obtained from the electrolysis experiment was detected by gas chromatography and the stability of the system was tested.The effects of different electrolysis voltages,electrolysis temperatures,and current densities on electrolysis hydrogen production were experimentally studied.The results showed that the hydrogen production remained stable after 5 hours,and reached 370 ml/min.The hydrogen production of the system increased with the increase of the electrolysis voltage,and increased with the increase of the temperature,but the influence of the voltage greater than the degree of influence of temperature.In addition,the hydrogen generation rate is proportional to the current density,and the voltage increases from 3.75 V to 7.85 V after the current density increases from 1000 A/m²to3000 A/m².（3）In order to explore the mechanism of side reactions in the hydrolysis experiments,density functional theory（DFT）based calculations were used to discuss the adsorption and dissociation behaviors of Cl₂on Cu O（111）perfect surfaces and oxygen vacancy surfaces.The adsorption behavior and reaction mechanism of Cl₂directly adsorbed on two Cu O（111）surfaces were analyzed by calculating the adsorption structure,adsorption energy,charge density difference,and density of states（DOS）of the system.The calculation results show that the most favorable adsorption site of Cl₂on the perfect Cu O（111）surface is the bridge site between two Cusub atoms.However,on the Cu O（111）surface with oxygen vacancies,two Cl atoms dissociate from Cl₂molecules and bind to Cu sites after optimization.The presence of oxygen vacancies is highly chemically reactive when it comes to the dissociation of Cl₂,which can significantly enhance the activity of Cu O.