Study On The Preparation And Decalcification Properties Of Amino Acid-terminated Polyether Phosphorus-free Copolymer Decalcifying Agent

In recent years,due to the shortage of crude oil resources,the deep exploitation of crude oil in the domestic and overseas was increased,which cause the crude oil becoming heavier and poorer in quality and the heavy metal content is also increasing.Calcium and other metals in crude oil and their compounds have great influence on the process of heavy oil processing and its product quality,which can easily lead to poisoning inactivation.In recent years,chelating decalcification technology,which was the focus of study,only need adding a specific chelating decalcifying agent into the crude oil during the desalination process to complete decalcification of crude oil.However,there are a series of problems such as poor adaptability to crude oil,low decalcification rate,high dosage,strong corrosive,poor water solubility and serious pollution problems.Therefore,the development of novel,efficient,environmentally friendly,corrosive and controlled,low-cost crude oil decalcifying agent is of great significance for the development of crude oil pretreatment process and the sustainable development of society.In this paper,allyl polyoxyethylene ether（APEG）,maleic anhydride（MA）,hydroxyethyl acrylate（HEA）and natural water-soluble amino acids using as raw materials,through green chemical design for the reaction route,reaction monomer,reaction conditions,a series of environmentally friendly ternary copolymer crude oil decalcifying agent was prepared.In this paper,Yichang pipeline crude oil was used to discuss decalcify of the decalcifying agent during the process of desalination and pretreatment of crude oil.And the mechanism of decalcifying of decalcifying agent of crude oil was discussed.The main research contents are exhibited as follows:（1）For APEAA-HEA-MA,it is found that the best synthesis condition of APEAA-HEA-MA is as following:the monomer molar ratio was n（APEAA）:n（HEA）:n（MA）=1:2:5,the polymerization temperature was 85oC,the reaction time was 2.0 h,the content for initiator was 5 wt%,and the content for chain transfer agent was 5 wt%.And the best conditions for electric desalting process is as following:the water content was 7%,the dosage for decalcifying agent was 100 ppm,and the desalting temperature was 135oC/130oC,and the calcium removal efficiency could reach up to 95%;（2）A series of amino acid-terminated polyethers terpolymer decalcifying agent was prepared using water-soluble amino acid with different structures,APEG,HEA and MA as raw materials,and the decalcifying agent named as APEGA-HEA-MA,APEGln-HEA-MA,APEThr-HEA-MA and APEAspn-HEA-MA.Yichang pipeline crude oil was used to discuss decalcify of the decalcifying agent during the process of desalination and pretreatment of crude oil.And the mechanism of decalcifying for amino acid-terminated polyethers terpolymer decalcifying agent of crude oil was proposed.（3）In order to enhance the decalcifying performance and lower the cost,several complex monomer including HPMA（15 wt%）,PAA（15 wt%）,NH₂CH₂SO₃H（20wt%）,（NH₄）₂C₂O₄（15 wt%）,DTAB（1 wt%）and C₄H₁₀O₂（4 wt%）were introduced to form a series of complex decalcifying agents with APEAA-HEA-MA and the results showed the aforementioned complex decalcifying agent C-18 exhibited the best decalcifying performance.When the C-18 was applied in the dynamic electric desalination evaluation device to complete the continuous decalcification of crude oil pilot test,the decalcification rate of 90%.And when the C-18 was applied in the electric desalination process in the Sinopec company workplace,the average calcium removal efficiency was 74.05%when the dosage was 80 ppm and the average calcium removal efficiency was 83.47%when the dosage was 100 ppm.