Key Technology Of Scattering System And Property Development Of Oil Drag Reducing Agent

The requirements for energy are more and more with the development of economy. The mineral oil is the important part of energy utilization technology. In five main transportation modes such as railway, road, airport, pipeline transportation developed fast because of rapid constructing speed, small floor area, environmental protection, low energy consumption, unlimitations by weather conditions and geography. At present, more than 90% of crude oil and end products are transported by pipeline.But the pipeline transportation also has serious defect that its elastic transportation capability is lower than other transportation systems. It is hard to forecast the oil reserves exactly during oil exploration, andthere are some unsure factors during the development of oil field. Even if the reserves of oil field will be accurately measured in future, the oil field also has developing stage, producing stage and decreasing stage. And the demand of oil products in every area will be various because of the economical development and the updating of oil Products. So it is demanded that the elastic pipeline has elastic throughput. Otherwise, the pipeline must have certain adjusting ability to throughput, when the pressure tightness decreases caused by the aging of pipeline, and when parallel pipelines are needed to be examined and repaired because of accidents with assurance of the flow rate.The best method to above questions is to use oil drag reducing agent. The drag reducing agent is a chemistry additives that can decrease the flow resistance and increasing the throughput. The oil drag reducing agent is used specially in oil transportation pipeline. The throughput of oil can be increased about 20%-30% adding several ppm oil drag reducing agent in it. The oil drag reducing agent is synthesized by long chainα-olefin coordinating polymerization. The molecular weight of oil drag reducing agent is about 6 million and it is in elastic state in room temperature. Before applying the oil drag reducing agent, it must be cooled to glass state, ground to powders in low temperature and scattered into dispersion. But the oil drag reducing agent particles in dispersion system sometimes stick together because of storage and environmental factors. In addition, the drag reducing ability of poly-α-olefin is irreversible, i.e. when the molecules of it encountered higher shear stress created by pipeline transportation pressure instruments, it can't have the drag reducing ability because of molecular degradation.Because of above reasons, several countries pay attention to the post-processing engineering technology and the theory and experimental study of anti-shear stress ability of drag reducing agent.This article studied deeply about the post-processing theory and the molecular design of new style anti-shear stress drag reducing polymer basing on prophase work. And on the basis of above theory studies, the exploitation of applying technologies was carried out. The main works can be summarized as the following:1. The theory study of post-processing of polymer drag reducing agentThe ideas of surface modification to poly-a-olefin particles were proposed in accordance with the defect of post-processing of polymer drag reducing agent. The theory of settlement and stratification of oil drag reducing agent in scattering process and interaction mechanism of molecules in microencapsulating process were analyzed by molecular dynamics and dissipative particle dynamics on basis of microencapsulation of poly-a-olefin particles.2. Development of post-processing technology of polymer drag reducing agentThe experimental study of microencapsulation of poly-a-olefin particles was carried out by adopting particle microencapsulation technology on basis of theory study of post-processing of polymer drag reducing agent. The microcapsules containing poly-a-olefin particles were prepared. Basing above studies, the pilot experiment of microencapsulation of poly-a-olefin oil drag reducing agent particles was carried out for purpose of preparation of oil drag reducing agent which can be stored stably and have environmental protection character for industry application.3. Molecular design of new style anti-shear stress drag reducing polymerThe special interactions of high molecules, i.e. hydrogen bonds and ion-ion bonds were deeply studied by molecular dynamics for purpose of perfect anti-shear stress character of oil drag reducing agent.4. Synthesis of new style anti-shear stress drag reducing polymerNew style anti-shear stress drag reducing polymer in which the inter-molecular reaction was the anti-shear stress unit was synthesized by adopting different ratio of non-polar and polar monomers on basis of theory study of it. The characters of anti-shear stress, drag reduction and rheology of new style anti-shear stress drag reducing polymer was detected for next studying of drag reduction mechanism. Basing on above researches, this article has several innovative achievements as following:1. The accumulative morphology of drag reducing copolymer in dissoluble alcohol was affected by temperature and concentration. The simulation results coincided with the stratification and accumulation phenomenon of suspension of traditional oil drag reducing agent. The molecules with branched chains maybe the best microencapsulating materials for absorbing on surface of drag reducing agent particles, long-chain alkyl sodium sulfate and sodium sulfonate were the choices of isolation agent molecular design.2. The microencapsulations of drag reducing agent by urea-formaldehyde polymerization and poly-urethane synthesis were determined as technology pilot experimental schemes. Two microcapsules containing oil drag reducing agent were prepared. The microcapsules prepared by pilot experiment had better particles size, morphology and storage stability than uncoated oil drag reducing agent particles as well as the microencapsulation have no influence to drag reducing rate. The suspension with pilot experimental samples had better thermo stability and vibrating stability than suspension with uncoated drag reducing agent. The methods and technologies of microencapsulation of oil drag reducing agent by urea-formaldehyde polymerization and poly-urethane synthesis were determined as the alternative schemes of microencapsulating industry application of oil drag reducing agent. The main technology parameters of these two technologies were determined and the technology process of microencapsulation by urea-formaldehyde polymerization was identified. 3. In the molecular design process of hydrogen bond anti-shear stress drag reducing polymer, the intensity of multiple hydrogen bonds on it synthesized by suitable monomers must be lower than that of covalent bonds, and they can be cracked earlier than covalent bonds in order to buffer the stress to the main chains of oil drag reducing agent. The single and double hydrogen bonds systems maybe the important choices. The molecular weight of drag reducing polymer can be increased by applying the binding energy and stability of multiple hydrogen bonds. The polar monomer choices of proton donor polymer of anti-shear stress oil drag reducing polymer maybe the high molecules with hydroxyl or weak acidic groups such as carboxyl groups. The polar monomer choices of proton accepter polymer of anti-shear stress oil drag reducing polymer maybe poly vinyl pyridine, poly ester with amino groups, poly oxyethylene, polyethylene pyrrole or polyacrylamide.4. The component of ion bonds anti-shear stress drag reducing polymer maybe a nonionic main chain on which there are some ionic unit. The branched chains are hydroxyl groups or quaternary ammonium salts. The anti-shear stress drag reducing polymer can be synthesized by copolymerization of different monomers. Anionic and cationic in pyridine type ion liquid can form intensive special interaction, so pyridine olefin may be the monomer choice of ion bonds anti-shear stress drag reducing polymer.5. In simulation of modification of poly--α-olefin molecules to ion bonds anti-shear stress drag reducing polymer, there were intensive interaction between oxygen atom of methanol, imidazole anion and other cations as well as between cellulose molecules, imidazole anion and other cations. Imidazole anion and other cations were important donor and accepter of formation of hydrogen bonds, which can be the additives of modification of poly--α-olefin molecules.6. Anti-shear stress polymers were synthesized by emulsion polymerization, in which proton donor polymer was dodecyl methacrylate/Methacrylate copolymer (LMA/MMA), and proton accepter polymers were dodecyl methacrylate/dimethylamino ethyl methacrylate copolymer (LMA/DMA) and dodecyl methacrylate/styrene/4-vinyl pyridine copolymer (LMA/S/4-VP). 7. The coordination of proton donor polymer and proton accepter polymer was helpful to accumulation of polymer molecules. The accumulating degree was increased with concentration. Proton donor polymer and proton accepter polymer in coordination polymer had synergy effect. The coordination polymer had better drag reducing rate and anti-shear stress stability than proton donor polymer and proton accepter polymer.8. The solutions of proton donor polymer and proton accepter polymer were typical pseudoplastic fluids. The solution of coordination polymer coincided with power law equation of pseudoplastic fluid in high shear rates. When it in low viscosity, it's nonlinear character increased. The rigidity of coordination polymer increased with polar monomer rate increasing. The relationship of reduced viscosity and concentration of solutions of proton donor polymer and proton accepter polymer was linear and coincided with typical Huggins equation, and that of coordination polymer coincided with description about special interaction polymer's relationship of reduced viscosity and concentration in Huggins equation.9. The design results of pilot experimental apparatus in anti-shear stress drag reducing polymer preparation technology confirmed that, there are only determination of materials and circumstances in emulsion polymerization and there is no technology problem in pilot experiment, so the chemistry engineering problem in amplification may not be considered.