Iron-rich Copper Concentrate Is Used In The Study Of Methane Chemical Chain Combustion

Chemical looping combustion?CLC?is an emerging and energy-saving combustion technology that uses fossil fuels to oxidize oxygen storage materials to produce CO₂ and H₂O during the recycling process,while capturing high concentrations of carbon dioxide from tail gas.As a result,it greatly reducing industrial costs and improving energy efficiency.Oxygen carrier?OC?play a very important role in chemical looping combustion technology,so the manufacture and selection of suitable oxygen carriers will significantly affect the cost of the chemical looping combustion process and the overall system combustion efficiency.The iron-rich copper concentrate not only has the natural advantage of the double metal oxygen carrier but also has the economic advantage of the mineral oxygen carrier,which makes it have great potential in the future industrialization of oxygen carrier.In this paper,the use of iron-rich copper concentrate as oxygen carrier for methane chemical looping combustion can not only rationalize the utilization of mineral resources,but also greatly reduce the production cost of oxygen carrier.In this paper,the original iron-rich copper concentrate is first calcined to achieve the basic requirements as an oxygen carrier.In the constant temperature cycle reaction experiment,methane was used as a reducing raw material,and a series of evaluations were made on the reactivity and cycleability of the oxygen carrier.It was found that the copper ore oxygen carrier had a CO₂selectivity of 95%when the reaction temperature was 900°C,and it was also very satisfactory in the subsequent stability test.A series of characterizations were also performed on the samples after the cycle and before the cycle,demonstrating that the reducibility of the copper ore oxygen carrier was improved after the cycle.The kinetics of the reduction process of iron-rich copper concentrate in the atmosphere of methane reduction was also studied.From the kinetic study of the thermogravimetric analyzer method,it can be found that the reduction reaction of the oxygen-rich copper concentrate oxygen carrier can be divided into a reduction of a faster reaction of Cu species and a reaction of a slower reaction of Fe species.The reduction process is controlled by a two-dimensional growth kernel model mechanism and a diffusion control mechanism,respectively.The activation energies of the two reduction processes were calculated to be 56.49 kJ/mol and 109.56 kJ/mol,respectively.It is comparable to the results reported in other literatures using synthetic copper-iron based oxides.This indicates that the reaction behavior of iron-rich copper concentrate with methane is similar to that of other copper-containing iron-based oxygen carrier materials.Due to the special structure and complex composition,the iron-rich copper concentrate oxygen carrier will have a lower stability during the cycle.Therefore,the copper ore oxygen carrier needs to be improved by means of modification which is effective without increasing its cost.Reaction performance and cycle performance.In this paper,the iron-rich copper ore is modified with red mud to obtain a composite oxygen carrier with excellent performance.Experiments have shown that the reactivity of oxygen carrier after mixing copper ore with red mud in an appropriate ratio?7:3?is effectively improved.The average conversion of CH₄ and the average selectivity of CO₂ are 86%and 95%,respectively.In addition,the composite oxygen carrier also has more stable cycle characteristics than the original copper ore oxygen carrier during the cycle.The SEM characterization also proves that the sintering phenomenon of the original copper ore oxygen carrier after the addition of red mud is obviously improved.The composite oxygen carrier mixed with copper ore and red mud has great potential for industrial chemical chain combustion,both in terms of economics and reaction performance.