Study On Catalytic Co-pyrolysis Performance And Life Cycle Evaluation Of Nitrogen Doped Porous Carbon Based Corn Stover

Faced with the rapid depletion of non-renewable resources and increasingly prominent climate change,people focus on the use of renewable energy.Biomass is the only renewable energy that can be directly converted into fuel.The development and utilization can not only make up for the demand of low-carbon energy,but also reduce environmental pollution.At present,there is still a gap between the development of biomass energy technology in China and the related fields abroad,and there are some problems,such as lower emission pollution and biomass conversion rate.Catalytic transformation has attracted more and more attention because of it’s high conversion rate and high value added chemicals and fuels.Previous study was conducted by increasing the conversion activity of loaded metal catalytic,but there is a higher cost and metal fall off to add pollution problem,so the study focused on the related areas of biomass carbon base catalyst,but the activity of ascension and aperture structure still need to improve,ensuring high selectivity and reducing pollution and so on.In this paper,KMn O₄was used as an activator to improve the pore structure of carbon,and the melamine was used as a nitrogen-doped raw material to enhance the activity,and a nitrogen-doped carbon-based catalyst was prepared.Through the influence of potassium permanganate and nitrogen doping on the pyrolysis products of corn stover,the best parameters of catalyst preparation were determined,and different proportions of potassium permanganate（CM=1:1,1:1.5,1:2）and different amounts of nitrogen doping（CMN=1:0.25,1:0.5,1:1）were set to optimize the production process.The influence trend of the proportion change on the product was analyzed,so as to determine the optimum proportion parameters for the preparation of catalyst,and applied to catalyze corn stover（CS）and pine nut husk（PNS）.Finally,the life cycle assessment of the catalyst preparation process was carried out to evaluate the impact of the process on the environment.The results showed that in the regulation of corn stover by potassium permanganate,the mass ratio of corn stover to potassium permanganate was 1:1.5,and the pyrolysis temperature was700℃.The results of Py-GCMS showed that the pyrolysis products were mainly oxygen-containing compounds after adding potassium permanganate.Among them,phenols accounted for 22-37%,and when the proportion was CM-1.5,the increased amount of phenolic substances was about 13.8%.In the study of nitrogen doping and temperature regulation on the products,the ratio of corn stover to nitrogen doping is 1:0.5,and the pyrolysis temperature is700℃.From the analysis of liquid components,it can be found that the product distribution trend is similar to that when potassium permanganate was added before,with oxygenated substances accounting for 50-70%of the main part,and phenolic substances accounting for 70-80%.The aromatic and phenolic contents of CMN-0.5 were higher than those of the other two groups,especially the phenolic substances accounted for about 44%.The kinetic calculation of the catalytic process shows that the reaction temperature is 500℃.The main diagram of catalysis is consistent with the F3 model,and the function of catalytic process can be obtained as g（a）=（1/2）[1/（1-a）^-2-1].Combined with the characterization results,CMN-0.5-700 was selected as the optimal catalyst for phenolic production.When the ratio of catalyst to pine nut husk and corn stover was 4:1,the best effect was achieved,and the content of phenol was 51.90%,which was9.78%higher than that without catalysis.When corn stover/catalyst=4:1,the phenol content is48.98%,which is 32.94%higher than that without catalysis,and the content of 4-vinyl-phenol is19.13%.In the life-cycle assessment of the preparation and catalytic process of nitrogenous doped catalysts,through the environmental assessment of four indicators,such as climate change（GWP）,primary energy consumption（PED）,Resource Depletion-water（WU）and acidification（AP）,The pyrolysis process has a great impact on the environment.In summary,the process parameters of nitrogen-doped carbon-based catalysts were determined according to the distribution characteristics of the products.The catalyst was CMN-0.5-700,the catalytic temperature was 500℃,and the ratio of biomass to catalyst was 4:1,which were the optimal phenolic catalytic parameters.