Synthesis And Performance Evaluation Of Polysiloxane Heavy Oil Demulsifier

At present, the world energy crisis becomes increasingly serious, and easily mined reserves of conventional crude oil continues to decline, so more and more countries are beginning to pay attention to the exploitation of heavy oil. According to statistics, in the whole world, heavy oil reserves are far greater than conventional crude oil reserves. Reserves of heavy oil resources are rich in our country. Reserve of heavy oil proven is from 15% to 20% of total oil reserve. Compared with the conventional crude oil, heavy oil contains high asphaltene and glioma, and its adsorption on the oil-water interface to form a solid interfacial film, thus heavy oil emulsion is much more difficult than ordinary crude oil emulsion dehydration. Conventional crude oil demulsifier has been not met the requirements of today’s heavy oil emulsion breaking, so the research and development of heavy oil demulsifier has important economic and social significance.The silicone polymer with side chain that methyl has the outstanding characteristics of low surface tension, and the side chains bonded hydrophilic lipophilic group make it have both hydrophilic performance and lipophilic performance. By adjusting the proportion of various hydrophilic lipophilic can synthesize a variety of silicone demulsifier. The basic structure of glioma and asphaltene molecules are composed of a plurality of aromatic rings fused aromatic hydrocarbons as the center, around the connections of a plurality of naphthenic ring and aromatic ring. Demulsifier with aromatic ring structure will have a good dissolution diffusion properties in heavy oil, which reflects the advantage of dehydration rate is fast and high dewatering rate.Firstly intermediate acrylic nonylphenol polyoxyethylene polyoxypropylene ester was synthesized by esterification, and then a new type of polysiloxane heavy oil demulsifier was synthesized by using methyl terminated polyether and self-made polyether ester modified silicone oil containing hydrogen. The process conditions of synthesis of intermediates and polysiloxane heavy oil demulsifier were studied and the demulsification performance of self-made heavy oil demulsifier was evaluated. the mian contents are as follows:(1) Under the catalysis of p-toluenesulfonic acid, intermediate acrylic nonylphenol polyoxyethylene polyoxypropylene ester was synthesized by esterification taking acrylic acidand nonylphenol polyoxyethylene polyoxypropylene etheras raw materials. The process conditions of synthesis of intermediate were discussed and its structure was characterized. The optimum synthesis condition are as follows: the reaction time was 6h, the reaction temperature was 130℃, the molar ratio of acrylic acid and nonylphenol polyoxyethylene polyoxypropylene ether was 5.0:1, catalyst dosage was 3%, and inhibitor dosage was 0.8%. Under this condition, the esterification rate reached 97.9%.(2) Under the catalysis of chloroplatinic acid, a polysiloxane heavy oil demulsifier was synthesized taking methyl terminated polyethe, self-made polyether ester(the molar ratio of polyether ester and methyl terminated polyether was 1:1) and 0.08% silicone oil containing hydrogen as raw materials. The process conditions of synthesis of demulsifier were discussed and its structure was characterized. The optimum synthesis condition are as follows: the reaction time was 8h, the reaction temperature was 95℃, the mole ratio of silicon hydrogen bond with the double bond was 1:1.20, and the amount of catalyst was 50μg/g. Under this condition, the Si-H conversion reached 93.5%. Surface tension test of polysiloxane heavy oil demulsifier aqueous solution showed that the critical micelle concentration was 0.8g/L,the lowest surface tension was 27.035 m N/m, and surface tension showed a trend of decrease with the increase of the molar ratio of polyether ester and methyl terminated polyether.(3) The demulsification of polysiloxane demulsifier on Chen Zhuang heavy oil emulsion was discussed. The optimum demulsification condition are as follows: the demulsifier-dosage was 200mg/L, the temperature was 75℃, the time was 2.5h, and the molar ratio of polyether ester and methyl terminated polyether was 3:1. Under this condition, the dehydration rate reached 83.5%. Compared with commercial demulsifiers as PFA8311、AE2010、PR4041 and SP169, it can be concluded that polysiloxane demulsifier on one hand reflects the advantage of high dehydration rate and high dewatering rate, on the other hand shows the disadvantage that oil-water interface is not neat and water is yellow after dehydrating.(4) The polysiloxane heavy oil demulsifier compounded with AE2010 was used for demulsification. Demulsification effect was the best when the dosage of homemade demulsifier was 120mg/L and the dosage of AE2010 was 80mg/L. Under the distribution proportion, the breaking temperature was 75℃, the breaking time was 2h, the dehydration rate reached 92.4%, and the oil-water interface was neat and water was clear after dehydrating.