Precipitation of nalkanes in diesel affects cold flow property With XRD pattern, shape of crystals is able to be studied But XRD pattern has not been applied to investigation of precipitation of crystals of n...Precipitation of nalkanes in diesel affects cold flow property With XRD pattern, shape of crystals is able to be studied But XRD pattern has not been applied to investigation of precipitation of crystals of nalkanes appearing in diesel In this paper, XRD pattern of a series of diesel flow improver(DFI), wax and mixture of wax and DFI are analyzed The relationship between character of XRD pattern and performance of DFI is studied When sharp peak between 10°～30° is little, shape of peak is ordered and curve of peak is smooth, performance of DFI is better XRD pattern of the mixture of wax and DFI shows noncrystalline structure has changed Hence it might be considered crystallization procedure of wax be affected by DFI This work is also helpful to the full understanding of the mechanism of展开更多
The improvement of the Cold Filter Plugging Point (CFPP) by an additive will depend on either the characteristics of the diesel or the additive itself. The ways in which cold flow improver interacts with the constitue...The improvement of the Cold Filter Plugging Point (CFPP) by an additive will depend on either the characteristics of the diesel or the additive itself. The ways in which cold flow improver interacts with the constituents of the fuels and the reasons for their efficiencies are far from fully elucidated. In this work , the contents of the n-paraffin in five kinds of diesels were tested by urea adduction, and the carbon distribution of n-paraffins was tested by temperature programmed gas chromatograph GC-14A and computed by the software for simulating distillation. Maximum likelihood method is applied to obtain μ and σ2 of the carbon distribution, and the deviation χ2 is computed. When the degrees of freedom is 4 and significance level (α) is 0.10, χ2_ 0.90(4)=7.779. If deviation χ2 is smaller than χ2_ 0.90(4), the hypothesis that the population is normal is accepted. The results show that the distributions of n-paraffin in these five kinds of diesels are normal. It can be found that the susceptibility of the diesel DQCH is weak and the variance σ2 of the carbon distribution in n-paraffin is only 1076.21 smaller than that for other diesels. The smaller the variance σ2 is, the weaker the susceptibility is. The susceptibility of the diesel LYL is also weak. The value of the statistic test quantity χ2 on the normal distribution of the n-paraffin in the diesel LYL is 4.112 bigger than other diesels . Statistic test quantity χ2 could reflect whether the carbon distribution of n-paraffin fits the normal distribution. When the carbon distribution of n-paraffin does not fit normal well, the wax settling does not match the agglomeration of flow improver. In this situation, the flow improver can’t interact with more wax crystal so that the CFPP of diesel can not be decreased.展开更多
文摘Precipitation of nalkanes in diesel affects cold flow property With XRD pattern, shape of crystals is able to be studied But XRD pattern has not been applied to investigation of precipitation of crystals of nalkanes appearing in diesel In this paper, XRD pattern of a series of diesel flow improver(DFI), wax and mixture of wax and DFI are analyzed The relationship between character of XRD pattern and performance of DFI is studied When sharp peak between 10°～30° is little, shape of peak is ordered and curve of peak is smooth, performance of DFI is better XRD pattern of the mixture of wax and DFI shows noncrystalline structure has changed Hence it might be considered crystallization procedure of wax be affected by DFI This work is also helpful to the full understanding of the mechanism of
文摘The improvement of the Cold Filter Plugging Point (CFPP) by an additive will depend on either the characteristics of the diesel or the additive itself. The ways in which cold flow improver interacts with the constituents of the fuels and the reasons for their efficiencies are far from fully elucidated. In this work , the contents of the n-paraffin in five kinds of diesels were tested by urea adduction, and the carbon distribution of n-paraffins was tested by temperature programmed gas chromatograph GC-14A and computed by the software for simulating distillation. Maximum likelihood method is applied to obtain μ and σ2 of the carbon distribution, and the deviation χ2 is computed. When the degrees of freedom is 4 and significance level (α) is 0.10, χ2_ 0.90(4)=7.779. If deviation χ2 is smaller than χ2_ 0.90(4), the hypothesis that the population is normal is accepted. The results show that the distributions of n-paraffin in these five kinds of diesels are normal. It can be found that the susceptibility of the diesel DQCH is weak and the variance σ2 of the carbon distribution in n-paraffin is only 1076.21 smaller than that for other diesels. The smaller the variance σ2 is, the weaker the susceptibility is. The susceptibility of the diesel LYL is also weak. The value of the statistic test quantity χ2 on the normal distribution of the n-paraffin in the diesel LYL is 4.112 bigger than other diesels . Statistic test quantity χ2 could reflect whether the carbon distribution of n-paraffin fits the normal distribution. When the carbon distribution of n-paraffin does not fit normal well, the wax settling does not match the agglomeration of flow improver. In this situation, the flow improver can’t interact with more wax crystal so that the CFPP of diesel can not be decreased.
