频率响应法研究噻吩在HZSM-5分子筛上的吸附行为

采用频率响应技术和智能重量分析仪研究了噻吩在HZSM-5分子筛上的吸附行为.利用智能重量分析仪测得噻吩在373 K的吸附等温线.在(0.2～6.0)×133.3 Pa压力范围及302～602 K温度范围内,利用频率响应技术测得了噻吩在HZSM-5分子筛上吸附的频率响应谱.结果显示,噻吩在HZSM-5分子筛上的传质过程的速率控制步骤为吸附过程,同时存在高频吸附和低频吸附两个不同的吸附过程.结合吸附等温线和Langmuir速率方程得出,高频吸附符合Langmuir模型,为单层吸附,高频吸附位N(2)5为0.922 mmol/g,高频吸附作用为噻吩和SiOH之间的作用;低频吸附不符合Langmuir模型,低频吸附位M(1)3为0.588 mmol/g,低频吸附作用为噻吩和SiOHAl之间的作用.噻吩在HZSM-5分子筛上的吸附以高频吸附为主.     

针入度对室温的敏感性与PI或PVN的关系

选用国内最具代表性的８种沥青，按照国际（ＧＢ／Ｔ４９０５）对针入度进行测定，通过平行实验和重度性试验，探讨了针入度对室温的敏感性与ＰＩ或ＰＶＮ的关系。     

CHARACTERIZATION OF PAVING ASPHALTS BY DIFFERENTIAL SCANNING CALORIMETRY

Differential Scanning Calorimetry (D.S.C.) has been used to characterize the thermal behavior of various paving asphalts and their chromatographic fractions. In a single determination, several parameters, such as the glass transition temperature of the hydrocarbon matrix and the crystallized fractions, may be determined with good reproducibility. The glass transition is attributed to the aromatic and one part of the saturated fractions. The rest of the satured fraction has been found responsible for the endoihermal effect observed on warming which corresponds to the dissolution into the matrix. A method of determination of the crystallized fractions is described, and a comparison with the L.C.P.C. (Laboratoire Central des Ponts et Chaussdes - French Highway Administration Laboratory) method is made. The L.C.P.C. method was found to underestimate the real percentage of the crystallized fractions.     

CHARACTERIZATION OF PAVING ASPHALTS BY DIFFERENTIAL SCANNING CALORIMETRY

ABSTRACT

Differential Scanning Calorimetry (D.S.C.) has been used to characterize the thermal behavior of various paving asphalts and their chromatographic fractions. In a single determination, several parameters, such as the glass transition temperature of the hydrocarbon matrix and the crystallized fractions, may be determined with good reproducibility. The glass transition is attributed to the aromatic and one part of the saturated fractions. The rest of the satured fraction has been found responsible for the endoihermal effect observed on warming which corresponds to the dissolution into the matrix. A method of determination of the crystallized fractions is described, and a comparison with the L.C.P.C. (Laboratoire Central des Ponts et Chaussdes - French Highway Administration Laboratory) method is made. The L.C.P.C. method was found to underestimate the real percentage of the crystallized fractions.     

聚合物改性沥青的的试验与评价

详细介绍了几种与聚合物改性沥青的储存稳定性、弹性等性能有关的试验与评价方法，简单列举其它一些特殊的试验与评价方法。     

PHYSICAL PROPERTIES AND CHARACTERIZATION OF VENEZUELAN HEAVY AND EXTRAHEAVY CRUDES AND BITUMENS

ABSTRACT

Several Venezuelan heavy and extraheavy crude oils and bitumens have been evaluated for various physical properties, namely, density, viscosity, thermal conductivity, specific heat and vapor pressure. The API gravity of the oils considered are in the range of 8 to 12° API. In addition, blends of these oils and bitumens, and dilutions with reflnary distillates and light crude oils (20 to 54° API) have also been analized. It was found that, with the exception of viscosity, there is no functional relation between the API gravity and the other physical properties studied. A dividend of this finding is that it allows for a simple correlation between the viscosity and diluent content, for mixtures of heavy and light crude oils.     

REACTION OF PHOSPHORIC ACID WITH THERMAL RESIDUES AND BITUMENS

ABSTRACT

The purpose of the work was to study the effect of the addition of small quantities of phosphoric acid (or P₂O₅), on the physical and chemical behaviour of petroleum residues and bitumens.

Phosphoric acid (and P₂O₅) reacts only with thermal products such as visbreaker (VB) residues and bitumens, and do not react with straight run (SR) products.

The unstable constituents of VB residues, i.e. carbonaceous material and part of the asphaltenes, contain significant amounts of free radicals which easily share electrons with phosphorous.

The resulting condensed particles are higher molecular wighht, polar material no longher soluble in the bitumen, and flocculate.

This reaction confirms the presence of stable free radicals in thermal bitumens and residues, suggests a way to neutralize their destabilizing effect.     

重油和沥青的结构基团分析方法

建立了一个从核磁共振谱和化学选择性氧化芳碳得到的烷链分布的数据以完整地估计重油和沥青的结构基团浓度及一系列结构参数的方法。结构基团包括环烷亚甲基、环烷桥头碳、环烷芳香碳、芳环桥头碳、α－亚甲基、环烷环上烷基取代碳等１７种碳型。结构参数包括单元芳环片环数、单元环烷环片环数、芳环上烷基取代度、环烷环上烷基取代度、桥链数等。给出了Ａｌｂｅｒｔａ４种沥青质和ＣｏｌｄＬａｋｅ瓦斯油的结构基团分析结果。     

AN INTEGRATED PROCESS FOR STABILIZATION AND UPGRADING OF RESIDUES AND BITUMENS

A three step process is proposed for stabilizing thermal residues and bitumens, such as visbreaker residues, and for upgrading SR bitumens used to produce stable polymer-modified bitumens.

The process is based on the addition of phosphorus compounds such as phosphoric or polyphosphoric acid to VB residues and bitumens, and to the utilization of the insoluble by-product for upgrading SR bitumens or for the preparation of very stable polymer modified bitumens.     

THEORETICAL BASIS OF THE STRUCTURE OF BITUMENS AND OTHER ORGANIC BINDERS

Abstract

For the development of a general theory, organic binders (OB) are considered as two-phase disperse systems. The particle of the dispersed phase (Ph) is a nucleus (asphaltene, polymer, other filler) which immobilizes a part of the dispersing medium (M). Ph is a whole in heat motion and deformation.

The type of the disperse structure (DS) in OB and the properties of OB depend on the Ph volume (C_v ) equal to the product of the weight content of Ph, voluminosity coefficient λ (a relationship of volumes of Ph and their nuclei), the relationship of Ph densities and their nuclei.

C_v is a criterion of the general classification of OB on types of DS. At C_v = 0.487 and C_v = 0.613 we supposed and observed structural transitions. This is the basis of the method of designing OB with the required DS.

In theory the C_v -reduced highest Newtonian viscosity curve has been desdribed, the rheological method for determining basic parameters of DS of binders has been developed. Parameters of DS of 18 model bitumens containing various asphaltenes have been calculated. An adhesive ability of OB is conditioned by Van der Waals forces between particles of the dispersed phase and determined by the interaction constant we proposed.     

CHARACTERIZATION OF ASPHALTS CEMENTS BY THERMOMICROSCOPY AND DIFFERENTIAL SCANNING CALORIMETRY: CORRELATION TO CLASSIC PHYSICAL PROPERTIES

ABSTRACT

Numerous thcrmoanalyttcal methods can be used to evaluate asphalt cements. Optical thermomicroscopy techniques such as phase contrast microscopy and polarized light microscopy have been used to directly observe the in situ crystallization of aliphatic, waxy fractions, and to monitor any changes in structure that occur with temperature. These visual changes are then correlated with enthalpy changes resulting from precipitation/dissolution as measured by Differential Scanning Calorimetry (DSC) to better understand their thermal behavior. Temperature cycling studies show the phenomenon of crystallization to be completely reversible.

Finally, the Tg and % crystallizable fraction as quantitatively determined by DSC are compared to classic physical properties of the asphalt cement. The Tg compares favorably to the glass transition temperature as measured by a dynamic mechanical analyzer at low frequencies, but correlations with the Fraass Brittle Temperature are lower than expected. Asphalts with large amounts of crystallizable material as measured by DSC show significant aberrations from a rheological mastercurve typical of homogeneous viscoelastic fluids, and these results become more pronounced with time. These same asphalts also exhibit changing rheological behavior as the thermal treatment of the sample is varied prior to testing. suggesting that crystallization requires time and fluidity for molecular agglomeration to occur.

Hence, asphalt can and docs exist as a beterogcncous, biphasic liquid at ambient temperatures when sufficient crystallizable fractions are present. DSC offers a rapid, accurate technique to quantify this phenomenon and predict its effect on asphalt performance     

GEOCHEMICAL CHARACTERIZATION AND RELATIONSHIP OF OILS AND SOLID BITUMENS FROM SE TURKEY

Solid bitumens from the Seridhalivein, occurring in the Upper Cretaceous—Palaeocene Germav Formation, and five oils from different oilfields in SE Turkey, were investigated by a variety of organic geochemical methods. Based on biomarker distributions (pristane/phytane, carbon number preference (CPI), Norhopane/hopane, extended hopane distribution, pregnanes/regular steranes), a marine carbonate depositional environment is inferred for the source of these oils. The oils are "early mature', as indicated by their ethylcholestane 20S/20S + 20R ratios, and the 17α(H), 21β(H)-bishomohopane 22S/22S + 22R ratios. Differences in relative abundance of some compounds typical of higher salinities in the depositional environment (docosane, pregnane) suggest different sources of facies variations within a common source. No aromatic sulfur compounds were detected in the oils.
The solid bitumens were characterized by a high abundance of dibenzothiophenes, naphthalenes, phenanthrenes and their alkyl-substituted homologues in the aromatic fractions, and an abundance of n-alkanes in the saturate fraction. The high maturity of the solid bitumen (epi-impsonite, R %equiv. ∽ 1.2) makes an interpretation on the origin of these substances difficult. An origin due to biodegradation of sulfur-rich oil is excluded, since the alkane and aromatic fractions do not show signs of a severe microbial degradation. The absence of sulfur compounds in the oil extracts and the pyrolysis products of the asphaltene fraction show genetic differences between the oils and solid bitumens of SE Turkey. Pyrolysis of the asphaltenes from the bitumen extracts and of the unextracted bitumens produced sulfur compounds similar to those found in the aromatic fraction.     

REACTION OF PHOSPHORIC ACID WITH THERMAL RESIDUES AND BITUMENS

The purpose of the work was to study the effect of the addition of small quantities of phosphoric acid (or P₂O₅), on the physical and chemical behaviour of petroleum residues and bitumens.

Phosphoric acid (and P₂O₅) reacts only with thermal products such as visbreaker (VB) residues and bitumens, and do not react with straight run (SR) products.

The unstable constituents of VB residues, i.e. carbonaceous material and part of the asphaltenes, contain significant amounts of free radicals which easily share electrons with phosphorous.

The resulting condensed particles are higher molecular wighht, polar material no longher soluble in the bitumen, and flocculate.

This reaction confirms the presence of stable free radicals in thermal bitumens and residues, suggests a way to neutralize their destabilizing effect.     

AN INTEGRATED PROCESS FOR STABILIZATION AND UPGRADING OF RESIDUES AND BITUMENS

ABSTRACT

A three step process is proposed for stabilizing thermal residues and bitumens, such as visbreaker residues, and for upgrading SR bitumens used to produce stable polymer-modified bitumens.

The process is based on the addition of phosphorus compounds such as phosphoric or polyphosphoric acid to VB residues and bitumens, and to the utilization of the insoluble by-product for upgrading SR bitumens or for the preparation of very stable polymer modified bitumens.     

INVESTIGATION OF RHEOLOGICAL AND PHYSICO-MECHANICAL PROPERTIES OF STRUCTURE -FORMATION COMPONENTS OF ROAD BITUMENS

This paper describes the interrelationship of the structure and properties of bitumen that are necessary for the design of high quality bituminous mixtures.     

REACTION OF VISBREAKER BITUMENS WITH SULFUR

The utilization of sulfur in bituminous binders started many years ago: a number of roads were paved in U.S. with SA (sulfur-asphalt) mixtures. Literature reports that, when mixing sulfur and asphalt, H₂S evolution starts at temperatures higher than 150°C.

By using thermal analysis techniques, the present paper shows that H₂S evolution begins at about 130°C for most types of bitumens. Kinetics of reaction between sulfur and visbreaker bitumens were also studied: the reaction order with respect to sulfur is equal to 0.5 for the three visbreaker bitumens considered in this work.     

A NEW SCHEME FOR THE FORMATION AND CLASSIFICATION OF BITUMENS

This paper discusses models of bitumen formation. Most liquid bitumens are formed during the middle stages of catagenesis (between approx. Ro equivalents of 0.4 and 1.15, respectively). "Progressive" naphthide formation is a process whereby organic matter and its derivatives gradually pass through a number of stages of alteration — three stages are generally recognized. By contrast , "regressive" naphthide formation is a "superimposed" process, involving microbial alteration and biochemical oxidation.
In addition to the above two general processes, three other, less important schemes of naphthide formation are recognised:
"Pyrodestructive bitumogenesis" results in the formation of "naphthoids"; these are bitumens generated close to an intruded heat source, which causes thermal destruction of organic matter.
"Dynamic-hydrothermal bitumogenesis" results in the generation of a complex group of bitumens, known as "naphthido-naphthoids", which are formed under conditions of dynamic metamorphism and hydrothermal activity accompanied by metasomatism.
Thirdly, the process of "phase-migrational" bitumogenesis results in the formation of two groups of bitumens: "asphaltenites" and "beta-asphaltenites".
This paper summarizes the Author's views on bitumen formation, based on new geological and geochemical data.     

INVESTIGATION OF RHEOLOGICAL AND PHYSICO-MECHANICAL PROPERTIES OF STRUCTURE -FORMATION COMPONENTS OF ROAD BITUMENS

ABSTRACT

This paper describes the interrelationship of the structure and properties of bitumen that are necessary for the design of high quality bituminous mixtures.     

CHARACTERIZATION STUDIES ON VISBREAKER RESIDUES AND BITUMENS

To better characterize the visbreaker (VB) residues and bitumens, and to study the differences between visbreaker and stright run (SR) products, four groups of samples (VB and SR residues and bitumens) were produced in some italian refineries. The samples were tested and analysed in order to know their viscosity at various temperatures, and their composition (chemical analysis and nmr). Adhesion, stability to oxidation, flow resistance of asphalt concrete were also evaluated for the bitumens. The study showed that nmr-aromaticity of the visbreaker residues and bitumens was increased by the visbreaking operation. Visbreaker bitumens were sensitive to oxidation and gave higher Marshall resistances. The susceptibility of penetration and viscosity to temperature changes was higer for visbreaker bitumens.     

CHARACTERIZATION STUDIES ON VISBREAKER RESIDUES AND BITUMENS

ABSTRACT

To better characterize the visbreaker (VB) residues and bitumens, and to study the differences between visbreaker and stright run (SR) products, four groups of samples (VB and SR residues and bitumens) were produced in some italian refineries. The samples were tested and analysed in order to know their viscosity at various temperatures, and their composition (chemical analysis and nmr). Adhesion, stability to oxidation, flow resistance of asphalt concrete were also evaluated for the bitumens. The study showed that nmr-aromaticity of the visbreaker residues and bitumens was increased by the visbreaking operation. Visbreaker bitumens were sensitive to oxidation and gave higher Marshall resistances. The susceptibility of penetration and viscosity to temperature changes was higer for visbreaker bitumens.