Homogeneous isotropic pitches with high softening points were prepared from vacuum-distilled heavy residue ethylene tar(ET-HR)by a two-step method of bromination and subsequent dehydrobromination/polycondensation.The ...Homogeneous isotropic pitches with high softening points were prepared from vacuum-distilled heavy residue ethylene tar(ET-HR)by a two-step method of bromination and subsequent dehydrobromination/polycondensation.The ET-HR was first brominated at 30 or 200℃,and then heat-treated at 350℃to enable the dehydrobromination/polycondensation reactions.GC/MS and LDI TOF/MS spectra indicated that the ET-HR was mainly composed of compounds containing 3-to 6-ring aromatic species with a considerable aliphatic chain content.Compared with thermal condensation alone,such a two-step method increased the softening point of the pitches from 152 to 264℃with a yield in the range of 62 wt.%-67 wt.%and a coking value in the range of 57 wt.%-77 wt.%,depending on the bromination temperature and the bromine content.Structural characterization of the as-prepared pitches by elemental analysis,1H NMR,FT-IR and LDI-TOF/MS showed increased aromatization and polymerization of the precursor during the dehydrobrominatio/polycondensation.All the homogeneous isotropic pitches showed an ability to transform into an anisotropic texture after coking at 800℃.展开更多
In the process of bromine production,because of lag adjustment methods,there are problems of adjusting delay,raw material wastage and low growth rate.By considering the nature of bromine production,with the help of fu...In the process of bromine production,because of lag adjustment methods,there are problems of adjusting delay,raw material wastage and low growth rate.By considering the nature of bromine production,with the help of fuzzy data processing method,computer detection and display technique,we designed an automatic detection instrument for the ratio of chlorine to bromine in oxidized liquid of bromine production.This instrument can be used to detect the different parameters of raw materials adjustment and control in real time,and afford assurance that raw materials will be adjusted in time.This paper briefly introduces the working mechanism,hardware and software design of the instrument.展开更多
文摘Homogeneous isotropic pitches with high softening points were prepared from vacuum-distilled heavy residue ethylene tar(ET-HR)by a two-step method of bromination and subsequent dehydrobromination/polycondensation.The ET-HR was first brominated at 30 or 200℃,and then heat-treated at 350℃to enable the dehydrobromination/polycondensation reactions.GC/MS and LDI TOF/MS spectra indicated that the ET-HR was mainly composed of compounds containing 3-to 6-ring aromatic species with a considerable aliphatic chain content.Compared with thermal condensation alone,such a two-step method increased the softening point of the pitches from 152 to 264℃with a yield in the range of 62 wt.%-67 wt.%and a coking value in the range of 57 wt.%-77 wt.%,depending on the bromination temperature and the bromine content.Structural characterization of the as-prepared pitches by elemental analysis,1H NMR,FT-IR and LDI-TOF/MS showed increased aromatization and polymerization of the precursor during the dehydrobrominatio/polycondensation.All the homogeneous isotropic pitches showed an ability to transform into an anisotropic texture after coking at 800℃.
文摘In the process of bromine production,because of lag adjustment methods,there are problems of adjusting delay,raw material wastage and low growth rate.By considering the nature of bromine production,with the help of fuzzy data processing method,computer detection and display technique,we designed an automatic detection instrument for the ratio of chlorine to bromine in oxidized liquid of bromine production.This instrument can be used to detect the different parameters of raw materials adjustment and control in real time,and afford assurance that raw materials will be adjusted in time.This paper briefly introduces the working mechanism,hardware and software design of the instrument.
