Research On The Co-processing Behavior Of D.tertiolecta And Polypropylene

Renewable energy is significant to solve the environment problem caused by excessive use of fossil energy,and has been focused in the field of energy.Because of the advantages like strong photosynthesis,do not take up the cultivated land and short of the growth cycle,the microalgae as the third generation of biofuels has broad development prospects.However,the bio-oil translate directly by microalgae is still has some disadvantages,such as low calorific value,high oxygen content and high acid value,seriously hindered the practical application of the bio-oil.Therefore,improving the quality of bio-oil is a key way for the development of biomass energy.As a kind of effective method,co-processing of plastic and biomass has received the widespread attention.So far,the co-processing object of plastic focuses on the terrestrial biomass?such as cellulose,etc.?,microalgae and plastic is less reported.At the same time,the interaction mechanism of plastic co-processing with biomass is not yet clear.Based on above,this paper select D.tertiolecta and polypropylene?PP?as the research object,respectively investigates the co-pyrolysis and co-liquefaction processes of microalgae and plastic,the main results were as follows:Thermogravimetric analysis results show that D.tertiolecta mainly cracking in the range of 200-600?,PP thermolysis between 350-550?.The co-pyrolysis of D.tertiolecta and PP is obviously a segmented process.In total co-pyrolysis process,D.tertiolecta mainly pyrolysis between 150-410?,while PP mainly pyrolysis 410-600?.When the particle size of PP small enough?below 120 mesh?,add PP can reduce the pyrolysis temperature and the reaction activation energy of D.tertiolecta,while the existence of D.tertiolecta will higher the pyrolysis temperature and activation energy of PP.Shows that PP has a certain role in promoting the thermolysis of D.tertiolecta.When PP: D.tertiolecta = 6:4,the interactions between them is most obvious.At this time,the pyrolysis activation energy of D.tertiolecta decreased to 142.9 k J/mol from 166.9 k J/mol.TG-FTIR and TG-MS analysis found that the existence of PP can reduce CO₂ produced by D.tertiolecta pyrolysis,shows that PP may react with CO₂ or the carbonyl compound generate CO₂.In co-liquefaction process,maximum synergistic effect between PP and D.tertiolecta was found when the ratio of PP and the algae is 2:8,show that solvent has great influence on the interaction between two raw materials.PP almost does not decompose in 340-370?,therefore,the addition of PP has little influence on the bio-oil production rate,but mainly impact the composition of the liquefaction oil products.When D.tertiolecta liquefied individually,the relative content of acid in the oil product can reach 18.73%,and add PP can greatly reduce acid content,when the ratio of PP and D.tertiolecta is 8:2,the acid content of oil products is lower than the detection limit of GC-MS?lower than 100ppm?.Finally,in this paper,the reaction pathways of the main components of the microalgae?carbohydrate,lipid,and protein?in the co-liquefaction process and their interaction mechanism with PP have been studied.The results indicate that the addition of PP has significant effect on the transform and decomposition pathways of sugar in microalgae as well as the Maillard reaction of nitrogen compounds.