Study On The Regulation Of Biomass Components On Phenolic Products In Bio-oil

Cellulose,hemicellulose,lignin and alkali and alkaline earth metallic species(AAEMs)are the main component of biomass.Through fast pyrolysis technology,biomass can produce pyrolysis gas,bio-oil and char.Bio-oil is rich in hundreds of organic compounds,of which phenolic compounds that is a high value-added chemicals can be used as part of the phenolic resin instead of adhesive,disinfectant,developer,and so on.Lignin is the main source of phenolic products in bio-oil.In this paper,the phenolic compounds were used as the target products,and the characteristics of phenol production by lignin pyrolysis were studied.Microcrystalline cellulose,xylan,alkaline lignin,corn stalks,potassium chloride and calcium chloride were used as experimental materials.Cellulose-lignin and xylan-lignin were mixed with different mass ratios(3:1,2:1,1:1),the corn stalks were pretreated with hydrochloric acid solution,and the lignin was mixed with potassium chloride and calcium chloride with different mass fraction(0.2,2,20wt%),respectively.The pyrolysis experiments were conducted in a fixed bed tubular furnace ranging from 450°C to 600°C.The effects of cellulose,hemicellulose and AAEMs on the pyrolysis products distribution and phenolic compounds production of lignin pyrolysis products were investigated.The changes of phenolic products in bio-oil produced by lignin pyrolysis provide valuable basic data for the conversion and utilization of bio-oil to high grade chemicals.The results show that with the increase of temperature,the bio-oil yield of the cellulose-lignin mixture and xylan-lignin mixture increase first and then decrease,and the highest oil yield was obtained at 500°C.When cellulose and lignin co-pyrolysis,the interaction of these contributes to the production of pyrolysis gas and inhibits the production of bio-oil and char,and the effects on the product increases with the increase of cellulose content.With the increase of xylan content,the inhibitory effect of xylan and lignin on pyrolysis was enhanced.At the same time,pyrolysis of xylan and lignin inhibited the production of coke and promoted the generation of gas.The influence of cellulose and xylan on the phenolic products distribution of lignin was studied by means of the overall evaluation method,the superposition method and the peak area ratio method.The results show that the effects of cellulose and xylan on the phenols produced by lignin pyrolysis are enhanced with the increase of temperature.With the increase of cellulose or xylan content,the effects of cellulose and xylan on the pyrolysis of lignin are weakening.For hydroxy phenols,guaiacols,and syringls,the cellulose promotes the increase in the yields of them derived from lignin,and the promotion on the three phenolic products is enhanced as the cellulose content increase.With the increase in xylan content,the formation of guaiacols and syringls is inhibited,and the production of hydroxy phenols is promoted.After treated corn stalk with HCl,the results show that AAEMs have significant effects on the distribution of pyrolysis products and phenolic products.AAEMs promote the pyrolysis of corn stalks to produce char and gas products,but inhibit the production of bio-oil.The results also show that the AAEMs promote the production of phenolic products,especially the effects on hydroxy phenols and guaiacols.The effects of potassium chloride and calcium chloride on the pyrolysis characteristics of lignin and its phenol production were investigated.Potassium chloride and calcium chloride promote lignin pyrolysis to produce gas and char products,inhibite the production of bio-oil,and the role of potassium chloride is stronger than calcium chloride.Potassium chloride promotes the formation of guaiacol,and the effect of calcium chloride on the formation of guaiacol is not obvious.With the increases of the content of potassium chloride and calcium chloride,the promoting effect of hydroxy phenols is also enhanced.