The Synergistic Effect On The Products Distribution In Co-pyrolysis Of Sargassum And Poplar

With the development of society,the dependence of fossil fuels is becoming more and more serious,and the energy crisis is becoming more and more conspicuous,so the development and utilization of clean energy is imperative.As a type of renewable energy with promising development potential,biomass has attracted extensive attention in recent years.China is an agricultural country with abundant biomass sources.It has a long coastline and a vast territory.Many scholars have done research on the separated pyrolysis biomass.However,it is still scarce to e research on mixed pyrolysis of large seaweed and forestry biomass,which has a potential to synergistically improve the yields and quality of bio-oil.This paper chose poplar with sargassum as raw material to explore the character of co-pyrolysis.The main research processes and conclusions are as follow:（1）The thermogravimetric analysis was used to analyze the co-pyrolysis characteristics of poplar and sargassum.The result showed that the initial pyrolysis temperature of poplar was higher and the final pyrolysis temperature was lower.The pyrolysis characteristics of sargassum were the opposite.With the addition of sargassum,the initial temperature of the mixed pyrolysis gradually decreased,the final temperature of the pyrolysis gradually increased,and the weight loo peak of the high temperature region gradually shifted to the right.（2）The time dependent trend of mixed pyrolysis products of poplar and sargassum was analyzed by on-line photoionization time-of-flight mass spectrometry.With the addition of sargassum,the signal intensity of the products gradually decreases.By analyzing some typical anhydrosugars,furans and linear carbonyl compounds,some typical products show a trend of increasing first and then decreasing,indicating that there is a synergistic effect between the co-pyrolysis of the two raw materials.At the same time,the addition of sargassum shorted the production time of some products.（3）The fixed bed reactor was used to analyze the co-pyrolysis characteristic of poplar and sargassum.The result show that the experiment values of product yields were different from the theoretical values,and the experimental values of solid phase product yields were higher than the theoretical values.The yield of liquid was lower than the theoretical values.Meanwhile,the co-pyrolysis promoted the formation of CO,CO₂,CH₄,C_n H_2n,C_n H_2n+2（n=2-3）,which reduced the content of H₂.The co-pyrolysis increased the phenol content in bio-oil significantly,as well as changing the carbon distribution of bio-oil.The specific surface of char was increased at a certain ratio.（4）The co-pyrolysis of poplar and washed sargassum was carried out on a fixed bed reactor.The yield of liquid was found to be significantly higher than theoretical value,and the yield of char was lower than the theoretical value.The co-pyrolysis promoted the formation of CO and CO₂,increased the yield of phenolic compounds,reduced the specific surface area and pore volume while increase the pore size of bio-char.