Jiaojiao Fang,Ting Zheng,Zhenyu Wu,Lihang Wu,Qinglong Xie,Fan Xia,Meizhen Lu,Yong Nie,Jianbing Ji
Epoxidized oils are eco-friendly plasticizers, which are industrially produced through the epoxidation reaction in a formic acid-hydrogen peroxide autocatalyzed system. The fundamental knowledge to describe the phase equilibrium of systems after epoxidation reaction is lacking, which is crucial for the design of the purification facilities. This work reported experimental data for the liquid–liquid equilibrium of three systems, i.e., epoxidized fatty acid methyl esters + formic acid + water, epoxidized fatty acid 2-ethylhexyl esters + formic acid + water, and epoxidized soybean oil + formic acid + water, in the temperature range (303.15–348.15) K under atmospheric pressure. The results indicated that the liquid–liquid equilibrium constant of formic acid in the systems followed the order of epoxidized fatty acid 2-ethylhexyl esters > epoxidized fatty acid methyl esters > epoxidized soybean oil. Moreover, the obtained experimental data were correlated using nonrandom two liquid (NRTL) and universal quasi chemical (UNIQUAC) models. The maximum root mean square deviation (RMSD) values as low as 0.0052 and 0.0263 were estimated using the NRTL and UNIQUAC model, respectively. The NRTL model is more suitable than the UNIQUAC model to describe the liquid–liquid equilibrium behavior of these ternary systems.
Luo Chen,Liu Huiqing,Zhou Song,Li Jingpeng,Li Xiang,Huang Yaowei
This study evaluated this thermal reaction behavior of oxidized and pyrolyzed oils containing diverse clay minerals by means of differential scanning calorimetry (DSC) technology. The catalytic role of various clay minerals for thermal reaction processes involving oxidized oil and pyrolyzed oil during in situ combustion (ISC) was investigated in conjunction with kinetic calculation methods as well. The results demonstrated that all four clay minerals could shorten its temperature region of oxidized oil low-temperature oxidation (LTO) stage, with the peak temperature during the LTO stage of oxidized oil containing montmorillonite being dramatically reduced. The catalytic role of montmorillonite and illite on oxidized oil is more powerful in the high-temperature oxidation (HTO) stage with higher peak heat flow. The Lewis acid sites within clay minerals affect free radical reactions within the crude oil pyrolysis process, and in situ reforming performance of 400°C pyrolyzed oils containing clay minerals is less effective, along with low heat release in the LTO stage. Clay minerals can considerably minimize the activation energy during thermal reaction of oxidized oil, contributing to the coke generation and conversion in the fuel deposition (FD) stage and boosting the success rate of the ISC procedure. The catalytic role of clay minerals in the oxidation and pyrolysis reactions of crude oil contributes to the prediction of fuel deposition and the expansion of the combustion front during ISC under diverse types of rock conditions.