| The pour point depressant (PPD) of diesel called low temperature flow improver,there has been a lot of reports on the study of the pour point depressant of diesel athome and abroad, but the sensitivity of diesel closely related to the n-paraffin of thediesel, and n-paraffin of the diesel of various regions was different in nature, so eachrefinery according to the characteristics of the difference study on pour pointdepressant. This paper took the refinery Urumqi petrochemical company diesel as thestudy subjects, studied on the reasons for different effects of depression of cold filterplugging point worked by PPD, compounded pour point depressant at the same time.At last, studied on the viscosity-temperature characteristics and the rheologicalproperties of diesel untreated and treated by PPD.The research mainly consists of three parts:(1) This part was focused on the compounding of PPD, took vinyl acetatecopolymer (EVA) as primary agent, four surfactants and four nitrogen compounds asassistant, compounded respectively.It found that the cold filter plugging point ofreconcile diesel has reduced8℃which treated by PPD. The PPD was made up of twoagents: EVA and sorbitan monooleate, and it compounded with proportion of3:1, andthe dosage of primary agent was500μg.g-1.Compareded the depression effect withT-1804PPD, and the results showed that blended diesel got same depression effectwith dose for750μg.g-1.(2)The part contributed to research the influence of n-paraffin of diesel on thesensitivity of diesel. Results showed that n-paraffin content and the distribution ofn-paraffin carbon number were two major factors on the sensitivity of diesel. Thesensitivity of diesel got worse gradually within the content of n-paraffin increased.When the diesel has met the following three conditions, diesel got bettersensitivity from PPD, these three conditions as followed: a. the distribution ofn-paraffin carbon number was approximated to normal distribution law; b. the ratio between the content of n-paraffin of carbon number greater than eighteen and contentof total n-paraffin less than25%; c. the content of n-paraffin was5%.(3) The part was concentrated on the viscosity versus-temperature propertiesand rheological properties of diesel with untreated diesel and diesel treated by PPD.As we known, RFCC diesel and blended diesel have batter sensitivity on PPD, and theresults indicated that viscosity of diesel treated by PPD less than the viscosity ofdiesel untreated by PPD at the same temperature when temperature dropped to coldfilter plugging point of diesel untreated by PPD. From the fitting rheologicalequations, which broadened the area of pseudo plastic fluid after addingadditives.straight-run diesel has bad sensitivity on PPD, so there were no changeabout the viscosity versus-temperature properties and rheological properties. |
