Study On Composition And Properties Of Liaohe Atmospheric Residue And Heavy Traffic Asphalt

Although the penetration property of straight-run residue of Liaohe ultraheavy oil can meet the quality standards of national heavy traffic paving petroleum asphalt,but it shows poor performance at flash point and evaporation losses.The modified residue of Liaohe ultraheavy oil can be qualified.In order to compare the differences of the properties,composition and performance of the two kinds of asphalt,and to explain the failure of evaporation at molecular level in depth,corresponding researches were conducted in this thesis.The molecular weight distribution curve,structural changing trend and FT-ICR MS characterization results of LHSHO AR(Liaohe ultraheavy oil)and modified LHSHO AR were compared.Then the two kinds of AR were fractionated into subfractions by SFEF(Superctitical fluid extraction and fractionation)with C5 as the solvent,properties,compositions and structures of two groups of subfractions were analyzed.The O2 species in the straight AR are mainly bicyclic,tricyclic,tetracyclic naphthenic acid or benzoic acid,which maybe the main compound affecting the loss in evaporation.For the structural composition,long side chain of modified AR was fractured partly,resulting in the reduction of evaporation loss after modification.The alcohol-alkali method was used to separate and purify the petroleum acid in AR.The refined petroleum acid was then characterized by FT-IR,elemental analysis,NMR and negative ions ESI FT-ICR MS.Composition and structure information were obtained by these analytical methods.The structural parameters of petroleum acid hydrocarbon groups were calculated using improved B-L method to further analyze the molecular structure of petroleum acid.The decarboxylation reaction of the carboxyl group,which is not directly connected with the ring,is easily occured during the thermal reforming process,this explains why the evaporation loss of modified AR is less than that of straight-run AR from the molecular level.Besides,the negative ion ESI FT-ICR MS results of the samples before and after alcohol and alkali extraction treatment proved this method is more suitable for extracting petroleum carboxylic acid from petroleum acid,especially for the petroleum carboxylic acid and the petroleum phenol with high condensation degree and high carbon number.In the last part,the properties and performance change of asphalt during the aging process was meticulous analyzed.The results show that the aging process is mainly dueto the polymerization of unsaturated bonds formed by dehydrogenation.In the molecular level,the carbon center of either N1 species or O2 species in AR were all concentrated.Poly-condensation reaction occurred of the O2 species at the late stage of aging process of AR.During the aging process of modified AR,that is because the O2 species may have some mild side-chain broken and open-loop reaction in the early stage,but no condensation reaction occurred in late period.The carboxyl carbon chain,which is directly linked to the ring,is more prone to break during the aging process,while the modification of AR also exacerbated this feature,the aging petroleum acid intends to possess more ring and shorter side chains.In addition,the property change of asphalt is closely related to its chemical composition and colloidal structure during the aging process.For the asphalt performance(to sum up): the modification process is not conducive to the improvement of asphalt performance.