Study On The Characteristics Of Copper Slag Catalytic Pyrolysis Of Biodiese

In the context of China’s transformation of energy development and vigorous development of non-fossil energy,energy transformation and upgrading is a necessary part of the future development of the non-ferrous metal smelting industry,and is of great significance to the successful achievement of China’s carbon neutral goals.Biodiesel from biomass liquid fuels is a biodegradable and environmentally sustainable energy source that has the potential to become an alternative energy source to petroleum diesel.Therefore,this study proposes a new idea to replace the conventional fuel and reducing agent used in the copper smelting process with biodiesel based on the fact that high temperature and excellent heat and mass transfer conditions in the copper melting pool will make the biodiesel rapidly pyrolysis.This study takes waste cooking oil biodiesel（WCO-Biodiesel）as the research object,focusing on the rapid pyrolysis and product formation mechanism of WCO-Biodiesel under the high temperature environment of copper bath melting,analyzing the catalytic pyrolysis characteristics of copper slag（CS）on WCO-Biodiesel,and providing the theoretical basis for the successful application of biomass liquid fuels in metallurgical industry.The study started with a thermogravimetric analysis（TGA）of WCO-Biodiesel and a mixture of WCO-Biodiesel and CS（mass ratio 1:10）.Based on the TGA analysis,the kinetic and thermodynamic parameters of the non-catalytic pyrolysis of WCO-Biodiesel and the CS-catalyzed WCO-Biodiesel pyrolysis were calculated using the Starink（STR）,Kissinger-Akahira-Sunose（KAS）and Flynn-Wall-Ozawa（FWO）methods.The activation energy（Eα）of non-catalytic pyrolysis ranged from 105.25 to218.86 k J/mol;the pre-exponential factor（A）was 2.86×10⁹ to 2.53×10²⁰ s^-1.The Eαof CS-catalyzed pyrolysis was 62.87 to 101.48 k J/mol;A was 2.12×10⁵ to 1.51×10⁹s^-1.The results indicated that CS reduces the Eαof the pyrolysis reaction.The pyrolysis reaction mechanism did not change significantly due to the effect of CS,and the trend of the reaction mechanism with conversion remained consistent with the nucleation and diffusion models（number of levels=1）Secondly,WCO-Biodiesel non-catalytic high-temperature fast pyrolysis and CS-catalyzed WCO-Biodiesel high-temperature fast pyrolysis experiments were conducted to investigate the effects of temperature and CS on the distribution of gas,liquid and solid products of WCO-Biodiesel pyrolysis,the release characteristics of gas products,the composition of liquid products and the physical and chemical properties of carbon accumulation products.The results showed that the long-chain products would be further pyrolyzed under the catalytic effect of CS,which promoted the formation of more gaseous products,reduced the formation of liquid products and carbon accumulation products,and changed the particle size of carbon accumulation products.With the increase of temperature,the components in the liquid products will be further transformed into PAHs under the influence of CS,and PAHs will then form carbon accumulation.Finally,the reduction of FeO in CS by the pyrolysis products of WCO-Biodiesel was investigated.In the reduction of Fe₃O₄ to FeO by Coke,the reduction reaction starts at 960.76℃.The apparent activation energy Eαvalue of 439.53 k J/mol and A value of 4.54×10¹² s^-1 were calculated according to the model fitting method（Coats-Redfern）.the reduction process follows the interface as the limiting surface reaction with order n=2（R2）.