Kun Chen

The Distribution of Ni and V in Resin and Asphaltene Subfractions and Its Variation During Thermal Processes

Ni and V deactivate catalysts and promote coking during heavy oil upgrading. Distribution of metals and metalloporphyrins, and its variation in thermal process, would benefit the more efficient upgrading. Majority of metals concentrate in resins and asphaltenes. To thoroughly study the metals distribution in these fractions, both were subdivided. It is indicated that the interactions between metalloporphyrins and asphaltenes play a significant role in metals distribution. Variation of metals distribution showed that the trend metals concentrated into heavier subfractions and was enhanced by thermal treatment and inhibited by hydrogen sources. Synergism was observed between hydrogen and hydrogen donor for the inhibition.

Ni, V, and Porphyrinic V Distribution and Its Role in Aggregation of Asphaltenes

Information on distribution of metals and metalloporphyrins can help to understand molecular interaction presented by metals and asphaltenes and possible participation of metals in aggregation of asphaltenes. Therefore, contents of metals and metalloporphyrins were determined in three asphaltene subfractions separated based on solubility. Compositions of the subfractions were confirmed by elemental analysis, vapor pressure osometry molecular weight, and 1H NMR, and molecular structures were simulated. The correlation between distribution of metals and metalloporphyrins and molecular composition was discussed. It indicates that metals interacting loosely with asphaltenes tend to be preferentially extracted into lighter fractions and present as metalloporphyrins, while a great portion of metals concentrates into the heavier fraction and presents as metal-nonporphyrins apparently due to strong interaction with asphaltenes. This suggests that distribution of metals plays a key role in determining the polarity and solubility of subfractions, and thus affects aggregation of asphaltenes. GRAPHICAL ABSTRACT

Synergism of Hydrogen and Oil Composition in Noncatalytic Upgrading of Petroleum Residues

Synergism of hydrogen and composition of oils in noncatalytic upgrading of different petroleum residues were analyzed. Residues were upgraded under temperature of 400°C and initial pressure of 4 MPa for 20 min in the presence of hydrogen or nitrogen, respectively. In addition, anthracene was used as chemical probe to quantify the hydrogen-donating ability of the three feedstocks and the contribution of hydrogen gas. Results show that hydrogen has better synergism with the residue that contains more naphthenic aromatic structure, heteroatom, and metals. Moreover, hydrogen activation possibilities limit the effect of the hydrogen solubility of the oils on upgrading.

Ethylene and propylene production from ethanol over Sr or Bi modified ZrO2 catalysts

The Sr or Bi modified ZrO2 catalysts were prepared by the co-precipitation method. The synthesized catalysts were characterized by X-ray diffraction, temperature programmed desorption, and N2 adsorption/desorption methods. All the synthesized catalysts were tested in the conversion of ethanol to light olefins. The results show that Sr or Bi modified ZrO2 catalysts have a remarkable effect on the surface area, crystalline phase, and acid–base properties. The total maximum yield of ethylene and propylene reaches 80.8% over Sr(1)/ZrO2. The catalytic stability over Sr(1)/ZrO2 is better than ZrO2 catalyst for the conversion of ethanol. The high catalytic selectivity of ethylene and propylene over Sr or Bi modified ZrO2 corresponds to the introduction of O vacancies. The mechanism may be related to acid and basic sites and redox reaction.

Compatibility of Heavy Blends Evaluated by Fouling and Its Relationship With Colloidal Stability

To predict oil compatibility is crucial because incompatibility could cause severe deposition and fouling problems. Therefore, compatibility of heavy oils and blends in different ratios were evaluated by fouling at heat transfer conditions. Thermal resistance and fouling rates were obtained on a fouling loop. Effect of colloidal stability based on asphaltene precipitation and SARA composition on fouling was also discussed. Results showed that different variations of fouling rate versus blending ratio were observed for these blending systems. For oils whose viscosities approach at heat conditions, the lower colloidal stability of blends is the higher fouling rate is. However, for oils with greatly different viscosities, inconsistency was observed between compatibility by the two indicators, which is attributed to remarkable change of flow condition. This indicates that both colloidal stability and flow condition play key roles in fouling. Oil compatibility at heat transfer condition is favored being predicted by fouling instead of correlating with the colloidal stability.

High Performance SiO2–ZrO2 Binary Oxide for Ethanol Conversion to Ethylene

Zirconia catalysts doped with Si were prepared by co-precipitation method. The effects of zirconium precursor, precipitant and Si on the selective conversion of ethanol to ethylene over zirconia catalysts were investigated. The addition of Si afforded high surface area and enlarged amount of acidic sites. Higher ethanol conversion and ethylene yield were obtained over SiO2–ZrO2 catalysts. The highest yield of ethylene reached 95.9% over SiO2–ZrO2 synthesized by ZrO(NO3)2·2H2O and (NH2CH2)2.Graphical Abstract

Effect of characteristics of inferior residues on thermal coke induction periods

Abstract Using 4 inferior residual oils as raw materials, the effect of feedstock properties on the characteristics of coke formation during initial thermal conversion process was studied. The results show that the influence for coke induction period of different oils affected by temperature can be measured with the sensitivity parameters. The shorter the coke induction period of the residue, the bigger the sensitivity parameter. The coke induction period has a higher decrease rate with the reaction temperature rising. The coke formation property generally depends on feedstocks basic properties, and the influence of various properties of inferior residual oils on coke formation is different under the same reaction conditions. Carbon residue, ash, relative molecular mass, asphaltene precipitation onset point and stability parameter have strong correlations with the coke induction period, especially for the colloidal stability of oil reflected by asphaltene precipitation onset point and stability parameter. The colloidal stability of the inferior residual oils is related to the coke formation characteristics. The worse the stability of the residue, the more likely the coke is to form. The coke forming process is a gradual destruction of the colloid system during thermal reaction.

Upgrading of Heavy Oil by Thermal Treatment with a Hydrogen Donor in a Continuous Flow Reactor

Thermal treatment of an inferior residue in the presence of a potential industrial hydrogen donor was conducted in a continuous flow reactor. Properties of liquid products and SARA compositions of residuals were analyzed. Moreover, stability of residuals was characterized by colloidal stability index. The results showed that in the presence of the hydrogen donor, the viscosities of product oils were reduced to a much lower point, the asphaltene formation of residuals was supressed and the stability of residuals was improved.