Experimental Research And Chemical Instrument Analysis On Characteristics And Reaction Mechanism Of Hydrogenated Palm Oil Pyrolysis

Hydrogenated Palm Oil?HPO?obtained from the hydrogenation reaction of palm oil was selected as the research object to investigate the pyrolysis characteristics and the pyrolysis mechanism.Additionally,the effects of different catalysts on the pyrolysis were also investigated.Thus,the pyrolysis mechanism of palm oil will be perfected.For preliminary understanding of the thermal properties of raw materials,the means of TG-DTG?TG-FTIR?RS-FTIR?TG-MS and Py-GC-MS were used to investigate the HPO.According to the effect of pyrolysis temperature on the distribution of the product determined by pyrolysis experiments,the process of saturated components cracking was divided into three stages,with 350?and 550?as the boundary points respectively.In addition,the chemical composition of bio-fuel oil in the pyrolytic products was confirmed by the means of FT-IR,NMR and GC-MS.It was found that the content of aromatic compounds decreased,the carbon chains of alkanes and olefins lengthened and the gas products decreased compared with pyrolysis results of palm oil.During the progress of pyrolysis,isomerization and alkylation reactions were observed obviously accompanied by the production of branched chain compounds.At the same time,the advanced means of ESI-FT-ICR MS analysis technique was used to detect the long-chain compounds with strong polarity in the bio-fuel oil to perfect the migration process of oxygen atom during the pyrolysis of vegetable oil combined with existing conclusions of that.To investigate the effects of different catalysts on the pyrolysis of HPO,catalytic pyrolysis experiments of the mixture powder of catalyst and HPO were carried out with three kinds of catalysts including alkaline catalyst,acid catalyst and molecular sieve catalyst,respectively.The bio-fuel oils obtained from catalytic pyrolysis were detected by GC-MS.And the results were analysed in three aspects including the changes of compositions and carbon distribution of bio-fuel oil,the changes of carbon distribution of main compositions and specific analysis of compounds with large change in content.It was found that KOH promoted the formation of fatty acids and long chain olefin,but inhibited the production of ketones,aldehydes,esters and other oxygen-containing compounds.Additionally,the inhibition of carbon bond breaking during the formation of alkenes and alcohols and the opposite effect during the formation of saturated aliphatic groups and ketones were observed.Acid catalyst Al₂O₃ promoted the formation of alcohols in pyrolysis process and inhibited the formation of long chain olefin and ketones.In addition,the carbon bond breaking of saturated aliphatic,long chain olefin and ketones was promoted,but the carbon bond breaking of fatty acids and alcohols was inhibited,which made the carbon distribution of bio-fuel oil tend to disperse.Molecular sieve catalyst MCM-41 can promote decarbonylation and deoxidation of alcohols during pyrolysis process,inhibit the formation of ketones and alcohols,and facilitate the concentration of carbon distribution of bio-fuel oil.In this paper,the means of RS-FTIR was first utilized to monitor pyrolysis reaction.Two model compounds,glyceryl mono-stearate and stearic acid were utilized to determine the initial temperature for deoxidation,dehydrogenation,and carbon bond breaking.The initial temperature of dehydrogenation reaction at 322?and the initial deoxidation reaction at 350?were observed.Additionally,decarbonylation was the dominant reaction of the deoxidation progress.The investigation of saturated components in palm oil was favorable for the research on the pyrolysis of palm oil and contribute to the pyrolysis transformation of palm oil and other vegetable oils.