Study On Methane Conversion Over Transition Metal Doped Mesoporous Carbon Cooperated With Plasma

With the increasing shortage of petroleum and coal resources,the proportion of natural gas resources in the energy structure is becoming higher and higher.Moreover,the reserves of natural gas and shale gas resources are abundant.And the energy pressure could be alleviated by making full use of natural gas.However,the direct chemical utilization of natural gas and shale gas is still in the early ages.The catalytically direct conversion natural gas and shale gas to C1 oxygen-containing compound with high added value,such as methanol,possesses important basic research significance and practical value.The main component of natural gas and shale gas is methane.Although the conversion and utilization of methane have been studied for a long time,the utilization way to achieve the industrial level is still indirect conversion methane,i.e.,the conversion of methane to syngas firstly,then the production of t methanol by using the obtained syngas.However,the cost of industrial syngas is too high,so it is extremely important to find a direct way to convert methane directly.Methane is particularly difficult to be activated due to its particular stability.In recent years,with the increasing usage of plasma in the field of chemistry,and the excellent activation capacity of plasma discharge,the experiment in this paper mainly converts directly methane into methanol under the conditions of plasma.Firstly,the pure plasma was used to study the methane-to-methanol,and an ideal experimental condition would be found by changing the input power,the flow rate of feed gas and the distribution ratio of feed gas.The experimental results showed that the methanol yield could achieve 6.2%at 200℃with 30 W of input power,t 30 m L/min of the total feed gas flow and N₂:CH₄:O₂=3:2:1 of the distribution ratio.The kinds of products for the oxidation of methane and plasma to methanol were complex and the selectivity of products were difficult to control.Based on the large amount of CO generated in the previous experiment,of the transition metal doped mesoporous carbon materials were filled into the discharge interval according to the Fischer-Tropsch synthesis principle,so as to whether the initial product could be further transformed on the packing surface for improving the selectivity of methanol.The transition metal incorporated mesoporous carbon materials were prepared by a simple template method,,and the ordered mesoporous materials,named OMC,were successfully prepared.In addition,a series of characterizations were performed.The prepared method saved the time compared with the traditional hard template method.The addition of fillers has an effect on the discharge area.And by tuning the experimental conditions including reaction temperature,metal doping amount and the length of the discharge interval,the synergistic effect could generate between the plasma and mesoporous carbon material.The experimental results showed that t the selectivity of methanol could be improved by adding the iron-doped mesoporous carbon materials.When the input power is 14W and the reaction temperature is150℃,the total feed gas flow rate is 60m L/min,and the distribution ratio is N₂:CH₄:O₂=3:2:1,The methanol selectivity over 3.76%Fe-OMC can achieve 21%,and the methanol yield was 1.5%for a feed gas of N₂:CH₄:O₂=3:2:1 and total feed gas flow rate of 60 m L/min at 150℃and the input power of 14 W.